WorldWideScience

Sample records for network media access

  1. Adaptive Media Access Control for Energy Harvesting - Wireless Sensor Networks

    DEFF Research Database (Denmark)

    Fafoutis, Xenofon; Dragoni, Nicola

    2012-01-01

    ODMAC (On-Demand Media Access Control) is a recently proposed MAC protocol designed to support individual duty cycles for Energy Harvesting — Wireless Sensor Networks (EH-WSNs). Individual duty cycles are vital for EH-WSNs, because they allow nodes to adapt their energy consumption to the ever...

  2. Media access control and resource allocation for next generation passive optical networks

    CERN Document Server

    Ansari, Nirwan

    2013-01-01

    This book focuses on various Passive optical networks (PONs)  types, including currently deployed Ethernet PON (EPON) and Gigabit PON (GPON) as well as next generation WDM PON and OFDM PON. Also this book examines the integrated optical and wireless access networks. Concentrating on two issues in these networks: media access control (MAC) and resource allocation. These two problems can greatly affect performances of PONs such as network resource utilization and QoS of end users. Finally this book will discuss various solutions to address the MAC and resource allocation issues in various PON networks.

  3. Fairness problems at the media access level for high-speed networks

    Science.gov (United States)

    Maly, Kurt J.; Zhang, L.; Game, David

    1990-01-01

    Most lower speed (approx. 10 Mbps) local area networks use adaptive or random access protocols like Ethernet. Others at higher speed use demand assignment like token or slotted rings. These include Cambridge ring and electronic token ring systems. Fairness issues in representatives of such protocols are discussed. In particular, Fiber Distributed Data Interface (FDDI) was selected as a demand access protocol using tokens, Carrier Sensed Multiple Access/Ring Network (CSMA/RN) a random access protocol, and Distributed Queue Dual Bus (DQDB) a demand access protocol using reservations. Fairness at the media access level was the focus, i.e., attaining access or being excessively delayed when a message is queued to be sent as a function of network location. Within that framework, the essential fairness of FDDI was observed along with severe fairness problems in DQDB and some problems for CSMA/RN. Several modifications were investigated and their ameliorative effect is shown. Finally, a unified presentation which allows comparisons of the three protocols' fairness when normalized to their capacity is given.

  4. One4All Cooperative Media Access Strategy in Infrastructure Based Distributed Wireless Networks

    DEFF Research Database (Denmark)

    Zhang, Qi; Fitzek, Frank H.P.; Iversen, Villy Bæk

    2008-01-01

    a cooperative cluster using their short-range air interface and one device contends the channel for all the devices within the cluster. This strategy reduces the number of mobile devices involved in the collision process for the wireless medium resulting in larger throughput, smaller access delay, and less......In this paper we propose the one4all cooperative access strategy to introduce a more efficient media access strategy for wireless networks. The one4all scheme is designed for the infrastructure based distributed wireless network architecture. The basic idea is that mobile devices can form...... energy consumption. Based on an analytical model, the proposed strategy is compared with the two existing strategies RTS/CTS (request to send/ clear to send) and packet aggregation. The results show that the proposed cooperative scheme has similar throughput performance as packet aggregation and it has...

  5. An energy-efficient rate adaptive media access protocol (RA-MAC) for long-lived sensor networks.

    Science.gov (United States)

    Hu, Wen; Chen, Quanjun; Corke, Peter; O'Rourke, Damien

    2010-01-01

    We introduce an energy-efficient Rate Adaptive Media Access Control (RA-MAC) algorithm for long-lived Wireless Sensor Networks (WSNs). Previous research shows that the dynamic and lossy nature of wireless communications is one of the major challenges to reliable data delivery in WSNs. RA-MAC achieves high link reliability in such situations by dynamically trading off data rate for channel gain. The extra gain that can be achieved reduces the packet loss rate which contributes to reduced energy expenditure through a reduced numbers of retransmissions. We achieve this at the expense of raw bit rate which generally far exceeds the application's link requirement. To minimize communication energy consumption, RA-MAC selects the optimal data rate based on the estimated link quality at each data rate and an analytical model of the energy consumption. Our model shows how the selected data rate depends on different channel conditions in order to minimize energy consumption. We have implemented RA-MAC in TinyOS for an off-the-shelf sensor platform (the TinyNode) on top of a state-of-the-art WSN Media Access Control Protocol, SCP-MAC, and evaluated its performance by comparing our implementation with the original SCP-MAC using both simulation and experiment.

  6. Optical Access Networks

    Science.gov (United States)

    Zheng, Jun; Ansari, Nirwan

    2005-06-01

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

  7. Optical Access Networks

    Science.gov (United States)

    Zheng, Jun; Ansari, Nirwan

    2005-01-01

    Call for Papers: Optical Access Networks Guest Editors Jun Zheng, University of Ottawa Nirwan Ansari, New Jersey Institute of Technology Submission Deadline: 1 June 2005 h2>Backgroundh2> With the wide deployment of fiber-optic technology over the past two decades, we have witnessed a tremendous growth of bandwidth capacity in the backbone networks of today's telecommunications infrastructure. However, access networks, which cover the "last-mile" areas and serve numerous residential and small business users, have not been scaled up commensurately. The local subscriber lines for telephone and cable television are still using twisted pairs and coaxial cables. Most residential connections to the Internet are still through dial-up modems operating at a low speed on twisted pairs. As the demand for access bandwidth increases with emerging high-bandwidth applications, such as distance learning, high-definition television (HDTV), and video on demand (VoD), the last-mile access networks have become a bandwidth bottleneck in today's telecommunications infrastructure. To ease this bottleneck, it is imperative to provide sufficient bandwidth capacity in the access networks to open the bottleneck and thus present more opportunities for the provisioning of multiservices. Optical access solutions promise huge bandwidth to service providers and low-cost high-bandwidth services to end users and are therefore widely considered the technology of choice for next-generation access networks. To realize the vision of optical access networks, however, many key issues still need to be addressed, such as network architectures, signaling protocols, and implementation standards. The major challenges lie in the fact that an optical solution must be not only robust, scalable, and flexible, but also implemented at a low cost comparable to that of existing access solutions in order to increase the economic viability of many potential high-bandwidth applications. In recent years, optical access

  8. Fixed Access Network Sharing

    Science.gov (United States)

    Cornaglia, Bruno; Young, Gavin; Marchetta, Antonio

    2015-12-01

    Fixed broadband network deployments are moving inexorably to the use of Next Generation Access (NGA) technologies and architectures. These NGA deployments involve building fiber infrastructure increasingly closer to the customer in order to increase the proportion of fiber on the customer's access connection (Fibre-To-The-Home/Building/Door/Cabinet… i.e. FTTx). This increases the speed of services that can be sold and will be increasingly required to meet the demands of new generations of video services as we evolve from HDTV to "Ultra-HD TV" with 4k and 8k lines of video resolution. However, building fiber access networks is a costly endeavor. It requires significant capital in order to cover any significant geographic coverage. Hence many companies are forming partnerships and joint-ventures in order to share the NGA network construction costs. One form of such a partnership involves two companies agreeing to each build to cover a certain geographic area and then "cross-selling" NGA products to each other in order to access customers within their partner's footprint (NGA coverage area). This is tantamount to a bi-lateral wholesale partnership. The concept of Fixed Access Network Sharing (FANS) is to address the possibility of sharing infrastructure with a high degree of flexibility for all network operators involved. By providing greater configuration control over the NGA network infrastructure, the service provider has a greater ability to define the network and hence to define their product capabilities at the active layer. This gives the service provider partners greater product development autonomy plus the ability to differentiate from each other at the active network layer.

  9. Accessibility in complex networks

    Science.gov (United States)

    Travençolo, B. A. N.; da F. Costa, L.

    2008-12-01

    This Letter describes a method for the quantification of the diversity of non-linear dynamics in complex networks as a consequence of self-avoiding random walks. The methodology is analyzed in the context of theoretical models and illustrated with respect to the characterization of the accessibility in urban streets.

  10. A quantum access network.

    Science.gov (United States)

    Fröhlich, Bernd; Dynes, James F; Lucamarini, Marco; Sharpe, Andrew W; Yuan, Zhiliang; Shields, Andrew J

    2013-09-05

    The theoretically proven security of quantum key distribution (QKD) could revolutionize the way in which information exchange is protected in the future. Several field tests of QKD have proven it to be a reliable technology for cryptographic key exchange and have demonstrated nodal networks of point-to-point links. However, until now no convincing answer has been given to the question of how to extend the scope of QKD beyond niche applications in dedicated high security networks. Here we introduce and experimentally demonstrate the concept of a 'quantum access network': based on simple and cost-effective telecommunication technologies, the scheme can greatly expand the number of users in quantum networks and therefore vastly broaden their appeal. We show that a high-speed single-photon detector positioned at a network node can be shared between up to 64 users for exchanging secret keys with the node, thereby significantly reducing the hardware requirements for each user added to the network. This point-to-multipoint architecture removes one of the main obstacles restricting the widespread application of QKD. It presents a viable method for realizing multi-user QKD networks with efficient use of resources, and brings QKD closer to becoming a widespread technology.

  11. Metropolitan Access Network

    Directory of Open Access Journals (Sweden)

    Slavko Šarić

    2003-11-01

    Full Text Available The optical fibre is the highest quality transmission mediumfor broadband services, and therefore the new access cablenetwork has to be realized to the greatest extent and as closeas possible to the subscriber by means of the optical fibre cables,in accordance with the possibilities of the telecommunicationoperator. The development of digital technology in commutations,supported by the increasingly powerful systems of processorcontrol, development of optical communications andtransport technologies in the framework of SDH concepts, arereflected on the access telecommunication networks of the urbanareas. Urban areas are the most profitable regions in telecommunications.In planning of urban optical networks the fact should betaken as a guideline that only a well-organised urban networkwill allow high quality of service provision of the leased cablesto the end points of business customers.Business customers have greater requirements for the networkreliability, flexibility and maintainability, for the sake ofundisturbed telecommunication traffic.The optical medium based technology- FITL (fiber in theloop, provides almost limitless upgrading of the system regardingthe transmission bandwidths, as well as adaptation to allthe future customers' requirements.Considering the increase in the price of installing the coppercables, the prices of electronics and optical components arecontinuously falling. The application of the optical medium isincreasing and becoming more cost-effective, and due to higherreliability of the optical transmission systems the maintenancecosts are reduced.

  12. Multi-Channel Multi-Radio Using 802.11 Based Media Access for Sink Nodes in Wireless Sensor Networks

    Directory of Open Access Journals (Sweden)

    Kok-Keong Loo

    2011-05-01

    Full Text Available The next generation surveillance and multimedia systems will become increasingly deployed as wireless sensor networks in order to monitor parks, public places and for business usage. The convergence of data and telecommunication over IP-based networks has paved the way for wireless networks. Functions are becoming more intertwined by the compelling force of innovation and technology. For example, many closed-circuit TV premises surveillance systems now rely on transmitting their images and data over IP networks instead of standalone video circuits. These systems will increase their reliability in the future on wireless networks and on IEEE 802.11 networks. However, due to limited non-overlapping channels, delay, and congestion there will be problems at sink nodes. In this paper we provide necessary conditions to verify the feasibility of round robin technique in these networks at the sink nodes by using a technique to regulate multi-radio multichannel assignment. We demonstrate through simulations that dynamic channel assignment scheme using multi-radio, and multichannel configuration at a single sink node can perform close to optimal on the average while multiple sink node assignment also performs well. The methods proposed in this paper can be a valuable tool for network designers in planning network deployment and for optimizing different performance objectives.

  13. REACT: REcommending Access Control decisions To social media users

    OpenAIRE

    Misra, Gaurav; Such, Jose M.

    2017-01-01

    The problems that social media users have in appropriately controlling access to their content has been well documented in previous research. A promising method of providing assistance to users is by learning from the access control decisions made by them and making future recommendations. In this paper, we present REACT, a learning mechanism which utilizes information available in the social network in conjunction with information about the content to be shared to provide users with access c...

  14. Networks in the news media

    DEFF Research Database (Denmark)

    Bro, Peter

    When news reporters connect people in a single news story or in a series of coherent news stories they essentially construct networks in the news media. Networks through which social actors are aligned symbolically in written, visible or audible form. These socio-symbolic networks not only copy...... more formal types of social networks, but also complement or even substitute social networking elsewhere, and as such this particular type of social network offers people both inside and outside the news room new potentials - and problems. This article describe the basic vision of networks in the news...... media and discuss the importance of this analytical framework when it comes to understanding prevailing forms and norms in contemporary journalism....

  15. Network Access Control For Dummies

    CERN Document Server

    Kelley, Jay; Wessels, Denzil

    2009-01-01

    Network access control (NAC) is how you manage network security when your employees, partners, and guests need to access your network using laptops and mobile devices. Network Access Control For Dummies is where you learn how NAC works, how to implement a program, and how to take real-world challenges in stride. You'll learn how to deploy and maintain NAC in your environment, identify and apply NAC standards, and extend NAC for greater network security. Along the way you'll become familiar with what NAC is (and what it isn't) as well as the key business drivers for deploying NAC.Learn the step

  16. Unscrewing social media networks, twice

    DEFF Research Database (Denmark)

    Birkbak, Andreas

    2017-01-01

    Social media are often claimed to be an important new force in politics. One way to investigate such a claim is to follow an early call made in actor-network theory (ANT) to “unscrew” those entities that are assumed to be important and show how they are made up of heterogeneous networks of many...... different actors (Callon and Latour 1981). In this article I take steps towards unscrewing seven Facebook pages that were used to mobilize citizens for and against road pricing in Copenhagen in 2011-2012. But I encounter the difficulty that social media are already explicitly understood in Internet Studies...... that it can be combined with liberal notions of a singular public sphere (Somers 1995b; 1995a). In order to unscrew social media as a political force, I suggest that we need to work through both the assembling of social media networks and attend to corresponding reconstructions of liberal political narratives...

  17. The impact of wireless device access on content delivery networks

    OpenAIRE

    Denney, Justin; Race, Nicholas

    2003-01-01

    Content delivery network architectures are initiatives designed to support the effective delivery of continuous and discrete media to end-users. Mobile devices are now capable of exploiting services such as content delivery, but with the protocols governing the content delivery networks designed for wired networked topologies; an assessment of the impact of mobile devices on the network has never been undertaken. Wireless devices access causes significant issues in the ability of the media tr...

  18. Media and youth: access, exposure, and privatization.

    Science.gov (United States)

    Roberts, D F

    2000-08-01

    To describe U.S. youth's access and exposure to the full array of media, as well as the social contexts in which media exposure occurs. A cross-sectional national random sample of 2065 adolescents aged 8 through 18 years, including oversamples of African-American and Hispanic youth, completed questionnaires about use of television, videotapes, movies, computers, video games, radio, compact discs, tape players, books, newspapers, and magazines. U.S. youngsters are immersed in media. Most households contain most media (computers and video game systems are the exception); the majority of youth have their own personal media. The average youth devotes 6 3/4 h to media; simultaneous use of multiple media increases exposure to 8 h of media messages daily. Overall, media exposure and exposure to individual media vary as a function of age, gender, race/ethnicity, and family socioeconomic level. Television remains the dominant medium. About one-half of the youth sampled uses a computer daily. A substantial proportion of children's and adolescents' media use occurs in the absence of parents. American youth devote more time to media than to any other waking activity, as much as one-third of each day. This demands increased parental attention and research into the effects of such extensive exposure.

  19. Internet Access in School Library Media Centers.

    Science.gov (United States)

    Everhart, Nancy

    1997-01-01

    Examines Internet resources available for elementary school children and discusses why Internet access should be provided through school library media centers. Highlights include appropriate Web sites, a case study, equity of access, censorship, integrating Internet resources into the curriculum, Internet usage guidelines, and identification and…

  20. Personalised Access to Social Media

    NARCIS (Netherlands)

    M. Clements (Maarten)

    2010-01-01

    htmlabstractOn many websites users can personally contribute information, ranging from short text messages to photos and videos. Users can see the information contributed by others and respond to it. These social media actively engage their community in the structuring of the collection by making

  1. Personalised Access to Social Media

    NARCIS (Netherlands)

    Clements, M.

    2010-01-01

    On many websites users can personally contribute information, ranging from short text messages to photos and videos. Users can see the information contributed by others and respond to it. These social media actively engage their community in the structuring of the collection by making use of

  2. Signed Networks in Social Media

    CERN Document Server

    Leskovec, Jure; Kleinberg, Jon

    2010-01-01

    Relations between users on social media sites often reflect a mixture of positive (friendly) and negative (antagonistic) interactions. In contrast to the bulk of research on social networks that has focused almost exclusively on positive interpretations of links between people, we study how the interplay between positive and negative relationships affects the structure of on-line social networks. We connect our analyses to theories of signed networks from social psychology. We find that the classical theory of structural balance tends to capture certain common patterns of interaction, but that it is also at odds with some of the fundamental phenomena we observe --- particularly related to the evolving, directed nature of these on-line networks. We then develop an alternate theory of status that better explains the observed edge signs and provides insights into the underlying social mechanisms. Our work provides one of the first large-scale evaluations of theories of signed networks using on-line datasets, as ...

  3. International networking: connecting midwives through social media.

    Science.gov (United States)

    Stewart, S; Sidebotham, M; Davis, D

    2012-09-01

    This article reports on the 'Virtual International Day of the Midwife E-vent', an innovative initiative that uses social media to provide opportunities for learning and networking internationally. This e-vent was conceived of and initiated in 2009 by a small group of midwives with an interest in social media. The e-vent uses web conferencing software and schedules a presentation every hour for a 24-h period so as to reach midwives or other interested parties in all time zones of the globe. The authors draw on their experiences to describe the e-vent including the e-vent aims and organizing processes, and to report on participation trends over the 3-year period. The e-vent has seen significant growth over a 3-year period with participation increasing from an average of five participants per session to 50. The organizing committee has expanded to include an international team and they have extended the reach of the project by establishing a Facebook page. While the use of social media has its limitations, projects such as the International Day of the Midwife E-vent have real potential to increase access to educational materials and provide opportunities for international networking. © 2012 The Authors. International Nursing Review © 2012 International Council of Nurses.

  4. One Health in social networks and social media.

    Science.gov (United States)

    Mekaru, S R; Brownstein, J S

    2014-08-01

    In the rapidly evolving world of social media, social networks, mobile applications and citizen science, online communities can develop organically and separately from larger or more established organisations. The One Health online community is experiencing expansion from both the bottom up and the top down. In this paper, the authors review social media's strengths and weaknesses, earlier work examining Internet resources for One Health, the current state of One Health in social media (e.g. Facebook, Twitter, YouTube) and online social networking sites (e.g. LinkedIn and ResearchGate), as well as social media in One Health-related citizen science projects. While One Health has a fairly strong presence on websites, its social media presence is more limited and has an uneven geographic distribution. In work following the Stone Mountain Meeting,the One Health Global Network Task Force Report recommended the creation of an online community of practice. Professional social networks as well as the strategic use of social media should be employed in this effort. Finally, One Health-related research projects using volunteers (citizen science) often use social media to enhance their recruitment. Including these researchers in a community of practitioners would take full advantage of their existing social media presence. In conclusion, the interactive nature of social media, combined with increasing global Internet access, provides the One Health community with opportunities to meaningfully expand their community and promote their message.

  5. Social Media Networks and Gen Y

    OpenAIRE

    Manimekalai Jambulingam; Caroline Sumathi Selvarajah; Ambikai S. Thuraisingam

    2014-01-01

    This study aims to explore the various social media platforms and to investigate gender differences in the use of social media networks. For the past 10 years, the use of social media has grown tremendously, ultimately becoming an important part of our lives. A total of 142 undergraduates to participated in the study. All data were collected by using quantitative methods. The information obtained from this study can provide a guideline for understanding the usage of social media among members...

  6. Pandora's Box? Companion Papers on Motivation, Access and the Media.

    Science.gov (United States)

    Sargant, Naomi; Tuckett, Alan

    These two papers address the challenge of harnessing the most appropriate media technology to help learning and teaching into the next century. "Motivation, Access, and the Media," presents the case for greater access for learners to the various technologies. The paper makes the case for access to be free at the point of use and argues…

  7. Determining Open Education Related Social Media Usage Trends in Turkey Using a Holistic Social Network Analysis

    Science.gov (United States)

    Firat, Mehmet; Altinpulluk, Hakan; Kilinç, Hakan; Büyük, Köksal

    2017-01-01

    The aim of this study is to reveal Open Education related social media usage in Turkey through social network analyses. To this end, the most widely used social media network in Turkey, Facebook, was chosen. All the pages and groups created on Facebook related to Open Education were found. A total of 207 groups and 521 pages were accessed and…

  8. Optical Subsystems for Next Generation Access Networks

    DEFF Research Database (Denmark)

    Lazaro, J.A; Polo, V.; Schrenk, B.

    2011-01-01

    Recent optical technologies are providing higher flexibility to next generation access networks: on the one hand, providing progressive FTTx and specifically FTTH deployment, progressively shortening the copper access network; on the other hand, also opening fixed-mobile convergence solutions in ...

  9. Integration of Education: Using Social Media Networks to Engage Students

    Directory of Open Access Journals (Sweden)

    Risa Blair

    2014-10-01

    Full Text Available Any educator today will tell you that the strategies used in the classroom have evolved and changed with the access everyone has to technology. In a world with constant changes and shifts because of immediate access to information, the way course content is delivered must evolve and adjust to the new ways students learn. Engagement of students in course content and reaching learning objectives are the key elements educators strive for in every course. Enter social media networks and the ability to leverage the user activity with these applications in education. Now, educators can provide content which engages students and meets learning objectives the way students want to learn. By reviewing social media networks: Facebook, Pinterest, Instagram, Blogs, Twitter, and Evernote, educators can position themselves to be as technology-savvy as today's students.

  10. Empathic Cyberactivism: The Potential of Hyperconnected Social Media Networks and Empathic Virtual Reality for Feminism

    National Research Council Canada - National Science Library

    Penelope Kemekenidou

    2016-01-01

    ...: with the ubiquity and accessibility of ‘immortal’ online information, harassment and discrimination, shared via hyperconnected social media networks, can be taken to a new, much more visible level...

  11. Unscrewing social media networks, twice

    DEFF Research Database (Denmark)

    Birkbak, Andreas

    2017-01-01

    different actors (Callon and Latour 1981). In this article I take steps towards unscrewing seven Facebook pages that were used to mobilize citizens for and against road pricing in Copenhagen in 2011-2012. But I encounter the difficulty that social media are already explicitly understood in Internet Studies...

  12. Mission-Aware Medium Access Control in Random Access Networks

    OpenAIRE

    Park, Jaeok; Van Der Schaar, Mihaela

    2009-01-01

    We study mission-critical networking in wireless communication networks, where network users are subject to critical events such as emergencies and crises. If a critical event occurs to a user, the user needs to send necessary information for help as early as possible. However, most existing medium access control (MAC) protocols are not adequate to meet the urgent need for information transmission by users in a critical situation. In this paer, we propose a novel class of MAC protocols that u...

  13. Patterns of ownership and accessibility to information and media facilities in democratizing the media in Nigeria.

    Science.gov (United States)

    Okwudishu, C

    1988-01-01

    Nigeria needs to embrace technology and pursue private media ownership in order to achieve a democratic media. In recent years, mass media in Africa has become a force with augmenting power that has influenced government and regimes. A democratization of the African media is reliant on media ownership and accessibility of information. Within Nigeria, there is a government monopoly of the media and therefore a road block in the free flow of information. As well, Nigeria's current economic situation has made media accessibility an extravagance. The electronic media is far from effective as many areas have poor reception, no electricity, or face a language barrier. Because most of the print media is written in English, many Nigerians cannot comprehend the printed news.

  14. Secure Media Independent Handover Message Transport in Heterogeneous Networks

    Directory of Open Access Journals (Sweden)

    Cho Choong-Ho

    2009-01-01

    Full Text Available The IEEE 802.21 framework for Media Independent Handover (MIH provides seamless vertical handover support for multimode mobile terminals. MIH messages are exchanged over various wireless media between mobile terminals and access networks to facilitate seamless handover. This calls for the need to secure MIH messages against network security threats in the wireless medium. In this paper, we first analyze IPSec/IKEv2 and DTLS security solution for secure MIH message transport. We show that handover latency can be an impediment to the use of IPSec and DTLS solutions. To overcome the handover overhead and hence minimize authentication time, a new secure MIH message transport solution, referred as MIHSec in this paper, is proposed. Experimental results are obtained for MIH between WLAN and Ethernet networks and the impacts of MIH message security on the handover latency are evaluated for IPSec, DTLS, and MIHSec security solutions. The effectiveness of MIHSec is demonstrated.

  15. Design of a control-channel-based media-access-control protocol for HORNET

    Science.gov (United States)

    White, Ian M.; Rogge, Matthew S.; Shrikhande, Kapil; Kazovsky, Leonid G.

    2002-12-01

    The HORNET (hybrid optoelectronic ring network) architecture is a packet-over-WDM ring network that utilizes fast-tunable packet transmitters and wavelength routing to enable it to scale cost-effectively to ultrahigh capacities. Here we present the design of a novel control-channel-based media-access-control (MAC) protocol, which is optimized for variable-sized IP packets and addresses inherent fairness control issues in multiple-access ring networks. The design of the control channel, including the frame structure and a frame-synchronization protocol, is described in detail.

  16. THE DISTRIBUTION NETWORK DEVELOPEMENT IN PRINT MEDIA

    Directory of Open Access Journals (Sweden)

    Loredana Iordache

    2012-09-01

    Full Text Available In this article, we identify the characteristics of the distribution networks in print media and the features ofmarketing in mass media, emphasising the attempts initiated by the press in the context of the financial crisis. Theresearch was conducted through a case study on regional newspaper,, Gazeta de Sud'' The main problems analyzedwere decreasing newspaper circulation and advertising. The research taken into account trends and developmentsworldwide print media as well as print media particularities of Romania, with a focus on identifying factors thatcontributed to the closure of a significant number of newspapers, or their transition from printed version online format.The paper is mainly focused on some practical issues related to the way of organizing the print media sales networks,the authors elaborating proposals for the implementation of certain measures to increase the circulation, on the onehand, and on the hand, to increase the sale of ad space in the newspaper. Compared with other products, thenewspaper has unique characteristics caused by daily changing content, and therefore the product itself. Having ahighly perishable, the content of media products should always seen in relation to time, which requires more rapiddistribution and continuous production.

  17. Quality guaranteed media delivery over advanced network

    NARCIS (Netherlands)

    Zhao, Z.; Grosso, P.; van der Ham, J.; de Laat, C.; Fortino, G.; Palau, C.E.

    2012-01-01

    Moving large quantities of data between distributed parties is a frequently invoked process in data intensive applications, such as collaborative digital media development. These transfers often have high quality requirements on the network services, especially when they involve user interactions or

  18. Distributed medium access control in wireless networks

    CERN Document Server

    Wang, Ping

    2013-01-01

    This brief investigates distributed medium access control (MAC) with QoS provisioning for both single- and multi-hop wireless networks including wireless local area networks (WLANs), wireless ad hoc networks, and wireless mesh networks. For WLANs, an efficient MAC scheme and a call admission control algorithm are presented to provide guaranteed QoS for voice traffic and, at the same time, increase the voice capacity significantly compared with the current WLAN standard. In addition, a novel token-based scheduling scheme is proposed to provide great flexibility and facility to the network servi

  19. Achieving universal access to next generation networks

    DEFF Research Database (Denmark)

    Falch, Morten; Henten, Anders

    The paper examines investment dimensions of next generation networks in a universal service perspective in a European context. The question is how new network infrastructures for getting access to communication, information and entertainment services in the present and future information society...

  20. Optimizing the next generation optical access networks

    DEFF Research Database (Denmark)

    Amaya Fernández, Ferney Orlando; Soto, Ana Cardenas; Tafur Monroy, Idelfonso

    2009-01-01

    Several issues in the design and optimization of the next generation optical access network (NG-OAN) are presented. The noise, the distortion and the fiber optic nonlinearities are considered to optimize the video distribution link in a passive optical network (PON). A discussion of the effect of...

  1. THE IMAGE OF BALI TOURISM IN SOCIAL NETWORKING MEDIA

    Directory of Open Access Journals (Sweden)

    Ni Gusti Ayu Dewi Paramita Arisandi

    2016-03-01

    Full Text Available Tourism is growing very rapidly with the development of technology, especially information technology .Through information technology people can easily get access to information about various destinations and tourist attractions as well as hotel by online media communication. Therefore, this study was trying to use social media such as facebook and twitter, where both social media were widely used by companies engaged in tourism in the world as well as in Bali. Internet consists of several websites, but the most effective one to conduct the research on tourism such as webseries 2.0 or commonly called as social networking media. Social medias - Facebook and Twitter - both were wildly used by the companies running in the sector of tourism in Bali, such as Hotels, Villas, Restaurants, Spas, Travel Agents, Airlines, and Tourist Attraction Managements, to advertised their products and services in their respective field. Through those social media, tourists will be able to access the comments or reviews about the companies. The problem raised in this research is how Bali’s tourism data in social networking media were used and considered, and how was the image of Bali’s tourism in their point of viewbased on the research. The method used here was descriptive qualitative method which describes this phenomenon descriptively by analyzing the obtained comments on social networking media such as facebook and twitter, and then classified in the form of comments positive, negative, and unidentified comment. Afterwards comments were re-analyzed through 4A Approach which consist of Attraction, amenities, Ancillary, and Accessibility. Data which has been obtained re-analyzed via the data obtained from the homepage of (TripAdvisor and Agoda.com. In addition, to strengthen the research data obtained from the homepage of TripAdvisor and Agoda.com , then it has been elaborated on the point rating system which indicatedthat the company were registered in both of

  2. Personalizing Access to Learning Networks

    DEFF Research Database (Denmark)

    Dolog, Peter; Simon, Bernd; Nejdl, Wolfgang

    2008-01-01

    In this article, we describe a Smart Space for Learning™ (SS4L) framework and infrastructure that enables personalized access to distributed heterogeneous knowledge repositories. Helping a learner to choose an appropriate learning resource or activity is a key problem which we address in this fra......In this article, we describe a Smart Space for Learning™ (SS4L) framework and infrastructure that enables personalized access to distributed heterogeneous knowledge repositories. Helping a learner to choose an appropriate learning resource or activity is a key problem which we address...... in this framework, enabling personalized access to federated learning repositories with a vast number of learning offers. Our infrastructure includes personalization strategies both at the query and the query results level. Query rewriting is based on learning and language preferences; rule-based and ranking...

  3. Scalable Lunar Surface Networks and Adaptive Orbit Access Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Innovative network architecture, protocols, and algorithms are proposed for both lunar surface networks and orbit access networks. Firstly, an overlaying...

  4. Quantum secured gigabit optical access networks

    Science.gov (United States)

    Fröhlich, Bernd; Dynes, James F.; Lucamarini, Marco; Sharpe, Andrew W.; Tam, Simon W.-B.; Yuan, Zhiliang; Shields, Andrew J.

    2015-12-01

    Optical access networks connect multiple endpoints to a common network node via shared fibre infrastructure. They will play a vital role to scale up the number of users in quantum key distribution (QKD) networks. However, the presence of power splitters in the commonly used passive network architecture makes successful transmission of weak quantum signals challenging. This is especially true if QKD and data signals are multiplexed in the passive network. The splitter introduces an imbalance between quantum signal and Raman noise, which can prevent the recovery of the quantum signal completely. Here we introduce a method to overcome this limitation and demonstrate coexistence of multi-user QKD and full power data traffic from a gigabit passive optical network (GPON) for the first time. The dual feeder implementation is compatible with standard GPON architectures and can support up to 128 users, highlighting that quantum protected GPON networks could be commonplace in the future.

  5. Survey on Cloud Radio Access Network

    Directory of Open Access Journals (Sweden)

    Reeta Chhatani

    2016-01-01

    Full Text Available The existing wireless network will face the challenge of data tsunami in the near future. Densification of network will deal huge data traffic but will increase the interferences and network cost. At the same time, the existing wireless network is underutilized due to dynamic traffic. To deal with this adverse scenario, a change in the current network architecture is required. Based on virtualization, Cloud Radio Access Network (CRAN was proposed for wireless network. In CRAN the functionality of base station will be distributed into base band unit (BBU and remote radio heads (RRH which will achieve benefits of centralization. This paper presents a survey on CRAN centring on optimized resource allocation, energy efficiency and throughput maximization under fronthaul capacity. The existing solution and future opportunities in CRAN are also summarized.

  6. Efficient Access Control in Multimedia Social Networks

    Science.gov (United States)

    Sachan, Amit; Emmanuel, Sabu

    Multimedia social networks (MMSNs) have provided a convenient way to share multimedia contents such as images, videos, blogs, etc. Contents shared by a person can be easily accessed by anybody else over the Internet. However, due to various privacy, security, and legal concerns people often want to selectively share the contents only with their friends, family, colleagues, etc. Access control mechanisms play an important role in this situation. With access control mechanisms one can decide the persons who can access a shared content and who cannot. But continuously growing content uploads and accesses, fine grained access control requirements (e.g. different access control parameters for different parts in a picture), and specific access control requirements for multimedia contents can make the time complexity of access control to be very large. So, it is important to study an efficient access control mechanism suitable for MMSNs. In this chapter we present an efficient bit-vector transform based access control mechanism for MMSNs. The proposed approach is also compatible with other requirements of MMSNs, such as access rights modification, content deletion, etc. Mathematical analysis and experimental results show the effectiveness and efficiency of our proposed approach.

  7. Digital Neural Networks for New Media

    Science.gov (United States)

    Spaanenburg, Lambert; Malki, Suleyman

    Neural Networks perform computationally intensive tasks offering smart solutions for many new media applications. A number of analog and mixed digital/analog implementations have been proposed to smooth the algorithmic gap. But gradually, the digital implementation has become feasible, and the dedicated neural processor is on the horizon. A notable example is the Cellular Neural Network (CNN). The analog direction has matured for low-power, smart vision sensors; the digital direction is gradually being shaped into an IP-core for algorithm acceleration, especially for use in FPGA-based high-performance systems. The chapter discusses the next step towards a flexible and scalable multi-core engine using Application-Specific Integrated Processors (ASIP). This topographic engine can serve many new media tasks, as illustrated by novel applications in Homeland Security. We conclude with a view on the CNN kaleidoscope for the year 2020.

  8. Streaming movies, media, and instant access

    CERN Document Server

    Dixon, Wheeler Winston

    2013-01-01

    Film stocks are vanishing, but the iconic images of the silver screen remain -- albeit in new, sleeker formats. Today, viewers can instantly stream movies on televisions, computers, and smartphones. Gone are the days when films could only be seen in theaters or rented at video stores: movies are now accessible at the click of a button, and there are no reels, tapes, or discs to store. Any film or show worth keeping may be collected in the virtual cloud and accessed at will through services like Netflix, Hulu, and Amazon Instant.The movies have changed, and we are changing with them.

  9. [Pathology in social media networks. Recruitment campaign].

    Science.gov (United States)

    Alcaraz Mateos, Eduardo; Guerra Pastrián, Laura; Pijuan Andújar, Lara; López Solache, Laura; Zucchiatti, Adriana; García Ángel, Rubén; Prieto Cuadra, Juan Daniel; Labiano Miravalles, Tania; Carvalho, Rita; Gardner, Jerad M; Terrádez, Cristina; de Álava, Enrique

    Pathology is a speciality that is often poorly understood, not only by the general public, but also by clinicians. However, the recent widespread use of social media provides an opportunity to increase the visibility and comprehension of our profession. A working group was formed to carry out this task. The members of the Spanish Society of Pathology were contacted through its Communication and Social Projection Subcommittee to engage in the campaign #IWantYouForSEAP, to form a network on Twitter. The recruitment period was one month (August, 2016). The resulting project, developed during the XXVIII Congress of the SEAP-IAP, was registered using the analytical tools Symplur and Tweet Binder. 32 applications (29 pathologists, 2 histotechnicians, 1 administrative personnel) were received from all over Spain, including participants from 14 of the 17 Autonomous Regions, from 22 cities and 25 medical centres. The activity in relation to the hashtag #SEAP2017V used in the congress included 685 participants with 6704 tweets and 8,837,435 impressions. 28 of the 32 recruited by the #IWantYouForSEAP campaign participated, contributing with 2410 tweets, and generating 2,090,423 impressions (36% and 24% of the total, respectively). It is possible to promote and motivate teamwork within our discipline through social media networks. This preliminary experience of the use of social media networks in our scientific community has had encouraging results which have raised high expectations among participants. An appropriate use of social media networks could help to narrow the gap between pathologists and society. Copyright © 2017 Sociedad Española de Anatomía Patológica. Publicado por Elsevier España, S.L.U. All rights reserved.

  10. Protocol and networking design issues for local access WDM networks

    NARCIS (Netherlands)

    Salvador, M.R.; Heemstra de Groot, S.M.; Niemegeers, I.G.M.M.

    This report gives an overview of some of the protocol and networking design issues that have been addressed in Flamingo, a major ongoing project which investigates the use of WDM optical technology in local access networks. Quality of service delivery and wavelength assignment are focused on in this

  11. TCP Performance Enhancement for UMTS Access Network

    DEFF Research Database (Denmark)

    Hu, Liang

    2008-01-01

    is between UMTS access network and Internet. The split proxy divides the bandwidth delay product into two parts, resulting in two TCP connections with smaller bandwidth delay products. Simulation results show, the split TCP proxy can significantly improve the TCP performance under high bit rate DCH channel......We aim at optimize the TCP performance over UMTS access network challenged by the large delay bandwidth product that is mainly caused by the latency from the link layer ARQ retransmissions and diversity technique at physical layer. We propose to place a split TCP proxy at GGSN nodes which...

  12. Social Network Privacy via Evolving Access Control

    Science.gov (United States)

    di Crescenzo, Giovanni; Lipton, Richard J.

    We study the problem of limiting privacy loss due to data shared in a social network, where the basic underlying assumptions are that users are interested in sharing data and cannot be assumed to constantly follow appropriate privacy policies. Note that if these two assumptions do not hold, social network privacy is theoretically very easy to achieve; for instance, via some form of access control and confidentiality transformation on the data.

  13. Cloud Radio Access Network architecture. Towards 5G mobile networks

    DEFF Research Database (Denmark)

    Checko, Aleksandra

    Cloud Radio Access Network (C-RAN) is a novel mobile network architecture which can address a number of challenges that mobile operators face while trying to support ever-growing end-users’ needs towards 5th generation of mobile networks (5G). The main idea behind C-RAN is to split the base......, and for the analyzed scenario it can assure synchronization on the nanosecond level, fulfilling mobile network requirements. Furthermore, mechanisms to lower delay and jitter have been identified, namely: source scheduling and preemption. An innovative source scheduling scheme which can minimize jitter has been...

  14. Evaluation of Crosstalk Attacks in Access Networks

    DEFF Research Database (Denmark)

    Wagner, Christoph; Eiselt, Michael; Grobe, Klaus

    2016-01-01

    WDM-PON systems regained interest as low-cost solution for metro and access networks. We present a comparative analysis of resilience of wavelength-selective and wavelength-routed architectures against crosstalk attackers. We compare the vulnerability of these architectures against attacks...

  15. Spectrum access games for cognitive radio networks

    CSIR Research Space (South Africa)

    Masonta, MT

    2010-09-01

    Full Text Available received a wide acceptance in next generation and intelligent wireless communication systems. In this paper the authors make use of game theory approach to model and analyze cognitive radio networks in order to allow dynamic spectrum access in broadband...

  16. Think tanks in Denmark - Media Visibility and Network Relations

    DEFF Research Database (Denmark)

    Ørsten, Mark; Nørgaard Kristensen, Nete

    and the social democratic think thank the Economic Council of the Labor Movement (ECLM), and their influence on two of the three arenas: the media arena and the administrative arena. Theoretically, we draw on theories of neo-corporatism (Rommetvedt et al., 2012) and mediatization (Hjarvard, 2013; Strömbäck...... & Esser, 2014), and argue that media visibility and attention have become increasingly important for political actors seeking to influence decision makers (Rich & Weaver, 2000), but that corporatist networks and access to the administrative sphere are also still important arenas of influence (Binderkrantz...... have necessitated that actors seeking to influence political decisions mak-ing, such as interest groups, have had to find new ways of influencing policy making (Rom-metvedt et al., 2012). Studies of special interest groups in Denmark have pointed towards three important arenas of influence...

  17. Library Media Centers: Accessibility Issues in Rural Missouri

    Science.gov (United States)

    Cox, John E.; Lynch, Debra M.

    2006-01-01

    Based on a study by Cox (2004), this article deals with the needs of students with visual, hearing, and orthopedic impairments in terms of full access to school library media centers. Fictitious vignettes of student concerns as well as possible answers and thought-provoking questions expand Cox's rural Missouri-based study to a much wider audience…

  18. Who Gets to Play? Access, Popular Media and Participatory Literacies

    Science.gov (United States)

    Wohlwend, Karen E.

    2017-01-01

    Early literacy is often over-simplified as a set of skills for beginning reading, an approach which overlooks the ways that children play their way into cultures, using play as a literacy that accesses popular media as rich literary repertoires of characters and storylines. This article examines how children's play reveals their participatory…

  19. Local Poultry Farmers' Media Use, Access and Understanding of ...

    African Journals Online (AJOL)

    A two stage household based cluster sampling was conducted in Kaduna State to investigate local poultry farmers' media use, access and understanding to highly pathogenic avian influenza educational materials. Radio and television were appropriate channels for information dissemination to farmers. Television was ...

  20. Influence of Access to Media Resources on Adolescents' Attitude to ...

    African Journals Online (AJOL)

    This study investigated the influence of adolescents' access to media resources on attitude to sexual and reproductive health. The survey research design was adopted while the questionnaire was. used as the major instrument of data collection. Sixty copies of questionnaire were administered to the adolescents that were ...

  1. Networked Artworks: Complex Connections in New Media Art Education

    OpenAIRE

    Sweeny, Robert W

    2009-01-01

    This paper draws upon the notion of the networked artwork in order to suggest possibilities for new media art education, informed by research in complexity and systems theory, participatory media, and critical pedagogy.

  2. A Survey of Signed Network Mining in Social Media

    OpenAIRE

    Tang, Jiliang; Chang, Yi; Aggarwal, Charu; Liu, Huan

    2015-01-01

    Many real-world relations can be represented by signed networks with positive and negative links, as a result of which signed network analysis has attracted increasing attention from multiple disciplines. With the increasing prevalence of social media networks, signed network analysis has evolved from developing and measuring theories to mining tasks. In this article, we present a review of mining signed networks in the context of social media and discuss some promising research directions an...

  3. Social network media exposure and adolescent eating pathology in Fiji.

    Science.gov (United States)

    Becker, Anne E; Fay, Kristen E; Agnew-Blais, Jessica; Khan, A Nisha; Striegel-Moore, Ruth H; Gilman, Stephen E

    2011-01-01

    Mass media exposure has been associated with an increased risk of eating pathology. It is unknown whether indirect media exposure--such as the proliferation of media exposure in an individual's social network--is also associated with eating disorders. To test hypotheses that both individual (direct) and social network (indirect) mass media exposures were associated with eating pathology in Fiji. We assessed several kinds of mass media exposure, media influence, cultural orientation and eating pathology by self-report among adolescent female ethnic Fijians (n=523). We fitted a series of multiple regression models of eating pathology, assessed by the Eating Disorder Examination Questionnaire (EDE-Q), in which mass media exposures, sociodemographic characteristics and body mass index were entered as predictors. Both direct and indirect mass media exposures were associated with eating pathology in unadjusted analyses, whereas in adjusted analyses only social network media exposure was associated with eating pathology. This result was similar when eating pathology was operationalised as either a continuous or a categorical dependent variable (e.g. odds ratio OR=1.60, 95% CI 1.15-2.23 relating social network media exposure to upper-quartile EDE-Q scores). Subsequent analyses pointed to individual media influence as an important explanatory variable in this association. Social network media exposure was associated with eating pathology in this Fijian study sample, independent of direct media exposure and other cultural exposures. Findings warrant further investigation of its health impact in other populations.

  4. Accessibility and delay in random temporal networks

    Science.gov (United States)

    Tajbakhsh, Shahriar Etemadi; Coon, Justin P.; Simmons, David E.

    2017-09-01

    In a wide range of complex networks, the links between the nodes are temporal and may sporadically appear and disappear. This temporality is fundamental to analyzing the formation of paths within such networks. Moreover, the presence of the links between the nodes is a random process induced by nature in many real-world networks. In this paper, we study random temporal networks at a microscopic level and formulate the probability of accessibility from a node i to a node j after a certain number of discrete time units T . While solving the original problem is computationally intractable, we provide an upper and two lower bounds on this probability for a very general case with arbitrary time-varying probabilities of the links' existence. Moreover, for a special case where the links have identical probabilities across the network at each time slot, we obtain the exact probability of accessibility between any two nodes. Finally, we discuss scenarios where the information regarding the presence and absence of links is initially available in the form of time duration (of presence or absence intervals) continuous probability distributions rather than discrete probabilities over time slots. We provide a method for transforming such distributions to discrete probabilities, which enables us to apply the given bounds in this paper to a broader range of problem settings.

  5. Security Evaluation of Wireless Network Access Points

    Directory of Open Access Journals (Sweden)

    Kalniņš Rūdolfs

    2017-05-01

    Full Text Available The paper focuses on the real-world usage of IEEE 802.11 wireless network encryption and Wi-Fi Protected Setup (WPS function. A brief history on the development of encryption methods and WPS is given. Wireless scanning of 802.11 networks in a capital city has been performed, and the results of it have been analysed. To ascertain the knowledge about the security of wireless networks of the average user, an online survey has been conducted. To test the security of encryption methods and WPS function, practical attacks against private test wireless networks have been made. The authors conclude that the safest way to set up 802.11 network with a pre-shared key is to use Wi-Fi Protected Access 2 (WPA2 encryption without support for WPS function. Statistics in Riga shows that networks are often configured otherwise and thus vulnerable to attacks. Survey results prove that respondents are not well informed regarding the security of wireless networks.

  6. Access to Media and HIV Knowledge in India

    Directory of Open Access Journals (Sweden)

    Smriti Agarwal

    2014-06-01

    Full Text Available This paper aims to better understand the relationship between HIV knowledge and media exposure in India. We use a two-stage hurdle model to estimate the effect of media sources such as newspapers, radios and television on AIDS-related knowledge among Indian men and women using demographic health survey data. Overall, access to newspapers, radio, or television increases the likelihood of better HIV knowledge in both males and females by an order between 2% and 12%. These findings, albeit quantitatively small, suggest, even if indirectly, possible problems faced by AIDS campaigns and government programs in combating the HIV epidemic in India.

  7. Network value and optimum analysis on the mode of networked marketing in TV media

    Directory of Open Access Journals (Sweden)

    Xiao Dongpo

    2012-12-01

    Full Text Available Purpose: With the development of the networked marketing in TV media, it is important to do the research on network value and optimum analysis in this field.Design/methodology/approach: According to the research on the mode of networked marketing in TV media and Correlation theory, the essence of media marketing is creating, spreading and transferring values. The Participants of marketing value activities are in network, and value activities proceed in networked form. Network capability is important to TV media marketing activities.Findings: This article raises the direction of research of analysis and optimization about network based on the mode of networked marketing in TV media by studying TV media marketing Development Mechanism , network analysis and network value structure.

  8. Reliability monitoring of broadband access networks

    Directory of Open Access Journals (Sweden)

    Perlicki Krzysztof

    2017-06-01

    Full Text Available One of the critical issues for broadband accesss is how to test the access network infrastructure and quality of optical signal. The installation and powering up of an optical fiber access networks requires measurement techniques for verifying the link has been configured properly and that its constituent components are functioning correctly. Maintenance functions for a broadband optical access network are classified in two main categories: preventive maintenance and post-fault maintenance. The first one consists of: surveillance (to detect degradation in optical fiber components, or any other anomalous condition not preventing the signal transmission,, testing (to measure and locate any detected degradation or anomalous condition and control (fiber identification and fiber transfer to allow the testing of the link.. In turn second one consisits of: surveillance (to detect alarms or trouble reports and activate a procedure for restoration, testing (to locate the fault and/or verify the carrier performances after the restoration and remedy (fiber identification, fiber repair or fiber transfer to restore the link.

  9. Optical technologies in extended-reach access networks

    DEFF Research Database (Denmark)

    Wong, Elaine; Amaya Fernández, Ferney Orlando; Tafur Monroy, Idelfonso

    2009-01-01

    The merging of access and metro networks has been proposed as a solution to lower the unit cost of customer bandwidth. This paper reviews some of the recent advances and challenges in extended-reach optical access networks....

  10. Social networks as ICT collaborative and supportive learning media ...

    African Journals Online (AJOL)

    ... ICT collaborative and supportive learning media utilisation within the Nigerian educational system. The concept of ICT was concisely explained vis-à-vis the social network concept, theory and collaborative and supportive learning media utilisation. Different types of social network are highlighted among which Facebook, ...

  11. Social Media and Social Networking Applications for Teaching and Learning

    Science.gov (United States)

    Yeo, Michelle Mei Ling

    2014-01-01

    This paper aims to better understand the experiences of the youth and the educators with the tapping of social media like YouTube videos and the social networking application of Facebook for teaching and learning. This paper is interested in appropriating the benefits of leveraging of social media and networking applications like YouTube and…

  12. The Impact of Social Network Media on Brand Equity in SMEs

    OpenAIRE

    Mohammad Reza Nemat Gorgani

    2016-01-01

    Given the virtual world’s controlling role in everyday life, no one can ignore its crucial impacts on the physical world. In this term social network media play a considerable role in peoples’ daily lives and business by information sharing and the impressions of friends’ comments on own view. Dealing with change, continuing to develop in the dynamic marketplace furthermore, access to information on a level never experienced before are possible benefits to companies;Social media influences co...

  13. Research on optical access network remote management technology

    Science.gov (United States)

    Wang, Wayne; Zou, Chen; Luo, Wenyi

    2008-11-01

    This paper goal is to provide a framework for the remote configuration and management of services for PON (Passive Optical Network) access and fiber access. Also it defines how Auto-Configuration Servers (ACS) in the network can remotely configure, troubleshoot and manage a Passive Optical Network (PON) optical network termination (ONT) with layer 3 capabilities using the CPE WAN management protocol, TR-069.

  14. Army Social Media: Harnessing the Power of Networked Communications

    Science.gov (United States)

    2011-09-01

    9/1/2011 Army Social Media : harnessing the power of networked communications Report Documentation Page Form ApprovedOMB No. 0704-0188 Public...4. TITLE AND SUBTITLE Army Social Media : harnessing the power of networked communications 5a. CONTRACT NUMBER 5b. GRANT NUMBER 5c. PROGRAM...the Chief of Public Affairs,Online and Social Media Division,1500 Pentagon,Washington,DC,20301 8. PERFORMING ORGANIZATION REPORT NUMBER 9

  15. Softward-Defined Networking in Heterogeneous Radio Access Networks

    DEFF Research Database (Denmark)

    Yu, Hao

    2014-01-01

    Integrating diff erent wireless access technologies to provide users with data service will definitely result in a heterogeneous radio access network. Moving from one wireless domain to another causes traffic being switched from one interface to another. This results in a reestablishment of TCP c....... This paper provides a possible solution architecture and research direction for vertical handover problem by leveraging the concept of software - defined networking together with existing proposals....... connection due to the change of the assigned IP address. Frequent handovers may force users to perform re - logins or application restarts, which undoubtedly jeopardize the quality of experience. This vertical handover problem will not be trivial as mobility is becomin g a dominant factor in communications...

  16. Approximate Networking for Universal Internet Access

    Directory of Open Access Journals (Sweden)

    Junaid Qadir

    2017-12-01

    Full Text Available Despite the best efforts of networking researchers and practitioners, an ideal Internet experience is inaccessible to an overwhelming majority of people the world over, mainly due to the lack of cost-efficient ways of provisioning high-performance, global Internet. In this paper, we argue that instead of an exclusive focus on a utopian goal of universally accessible “ideal networking” (in which we have a high throughput and quality of service as well as low latency and congestion, we should consider providing “approximate networking” through the adoption of context-appropriate trade-offs. In this regard, we propose to leverage the advances in the emerging trend of “approximate computing” that rely on relaxing the bounds of precise/exact computing to provide new opportunities for improving the area, power, and performance efficiency of systems by orders of magnitude by embracing output errors in resilient applications. Furthermore, we propose to extend the dimensions of approximate computing towards various knobs available at network layers. Approximate networking can be used to provision “Global Access to the Internet for All” (GAIA in a pragmatically tiered fashion, in which different users around the world are provided a different context-appropriate (but still contextually functional Internet experience.

  17. Social media for professional development and networking opportunities in academia

    OpenAIRE

    Donelan, Helen

    2016-01-01

    The research reported on in this article explores the use of social media for work-related or professional purposes. In particular, it focuses on the perceptions and use of social media by academics in the UK. The purpose of the research was to explore the potential social media has to facilitate the changing landscape of higher education and support the individual academic in their role. Of particular interest is how specific social media tools are being used to enhance networking opportunit...

  18. Network interventions - How citizens’ social media networks influence their political participation

    DEFF Research Database (Denmark)

    Ohme, Jakob; de Vreese, Claes Holger; Albæk, Erik

    Social media platforms are special places of information exposure because they are structured around a user’s social network and not around content, like other news media. Studies could show that news exposure on social media can affect citizens’ political participation due to the personalized, t...... direct effects of social media exposure on participation but results indeed indicate that such effects are dependent on citizens’ network consistency.......Social media platforms are special places of information exposure because they are structured around a user’s social network and not around content, like other news media. Studies could show that news exposure on social media can affect citizens’ political participation due to the personalized......, targeted, & inadvertent exposure. However, previous research did not strongly focus on how the characteristics of a citizens’ social media network might alter this relationship. We tests how political information exposure via three different media channels affects political participation among Danish...

  19. Location-aware network operation for cloud radio access network

    KAUST Repository

    Wang, Fanggang

    2017-06-20

    One of the major challenges in effectively operating a cloud radio access network (C-RAN) is the excessive overhead signaling and computation load that scale rapidly with the size of the network. In this paper, the exploitation of location information of the mobile devices is proposed to address this challenge. We consider an approach in which location-assisted channel state information (CSI) acquisition methods are introduced to complement conventional pilot-based CSI acquisition methods and avoid excessive overhead signaling. A low-complexity algorithm is designed to maximize the sum rate. An adaptive algorithm is also proposed to address the uncertainty issue in CSI acquisition. Both theoretical and numerical analyses show that location information provides a new dimension to improve throughput for next-generation massive cooperative networks.

  20. Optical solutions for unbundled access network

    Science.gov (United States)

    Bacîş Vasile, Irina Bristena

    2015-02-01

    The unbundling technique requires finding solutions to guarantee the economic and technical performances imposed by the nature of the services that can be offered. One of the possible solutions is the optic one; choosing this solution is justified for the following reasons: it optimizes the use of the access network, which is the most expensive part of a network (about 50% of the total investment in telecommunications networks) while also being the least used (telephone traffic on the lines has a low cost); it increases the distance between the master station/central and the terminal of the subscriber; the development of the services offered to the subscribers is conditioned by the subscriber network. For broadband services there is a need for support for the introduction of high-speed transport. A proper identification of the factors that must be satisfied and a comprehensive financial evaluation of all resources involved, both the resources that are in the process of being bought as well as extensions are the main conditions that would lead to a correct choice. As there is no single optimal technology for all development scenarios, which can take into account all access systems, a successful implementation is always done by individual/particularized scenarios. The method used today for the selection of an optimal solution is based on statistics and analysis of the various, already implemented, solutions, and on the experience that was already gained; the main evaluation criterion and the most unbiased one is the ratio between the cost of the investment and the quality of service, while serving an as large as possible number of customers.

  1. Authentication Issues in Multi-Service Residential Access Networks

    OpenAIRE

    Rossebo, Judith; Ronan, John; Walsh, Kristian

    2003-01-01

    Multi-service residential access networks allow residential customers to choose amongst a variety of service offerings, over a range of Core Networks and subject to user requirements such as QoS, mobility, cost and availability. These issues place requirements on authentication for network access, with a need for mutual authentication of the residential gateway (RG) to the local access point (LAP). The EU-IST project TORRENT is building a testbed providing for multi-service residential access...

  2. Content, Accessibility, and Dissemination of Disaster Information via Social Media During the 2016 Louisiana Floods.

    Science.gov (United States)

    Scott, Katherine K; Errett, Nicole A

    2017-12-27

    Social media is becoming increasingly integrated into disaster response communication strategies of public health and emergency response agencies. We sought to assess the content, accessibility, and dissemination of social media communications made by government agencies during a disaster response. A cross-sectional analysis of social media posts made by federal, state, and local government, public health and emergency management agencies before, during, and after the 2016 Louisiana floods was conducted to determine their content, accessibility, and dissemination by level of government and time relative to disaster onset. Facebook and/or Twitter posts made by public agencies involved in the response to the 2016 Louisiana Flooding events (FEMA Disaster Declaration [DR-4277]) published between August 4 and September 16, 2016, publicly available online between February 21 and March 31, 2017, were included in the analysis. Content: The text of each post was assessed to determine whether it contained information on provision of situational awareness; addressing misconception, actionable requests; mental, behavioral, and emotional support; and/or recovery and rebuilding resources. Accessibility: A Flesh-Kincaid grade level of each post was calculated, and information on post language, originality, hyperlinks, visuals, videos, or hash tag was recorded. Dissemination: The average number of reacts/likes, shares/retweets, and comments per post was calculated. Most posts contained information related to situational awareness and recovery resources. There was an increase in messages during the first week of the disaster at all levels. Few posts were made in languages other than English. Compared with state and federal posts, local Facebook posts averaged fewer reacts, comments, and shares throughout the analysis period. Government agencies may maximize the use of social media platforms for disaster communications by establishing their social media network in advance of a

  3. Resource Allocation for Cloud Radio Access Networks

    KAUST Repository

    Dhifallah, Oussama

    2016-04-01

    Cloud-radio access network (CRAN) is expected to be the core network architecture for next generation mobile radio system. In CRANs, joint signal processing is performed at multiple cloud computing centers (clouds) that are connected to several base stations (BSs) via high capacity backhaul links. As a result, large-scale interference management and network power consumption reduction can be effectively achieved. Unlike recent works on CRANs which consider a single cloud processing and treat inter-cloud interference as background noise, the first part of this thesis focuses on the more practical scenario of the downlink of a multi-cloud radio access network where BSs are connected to each cloud through wireline backhaul links. Assume that each cloud serves a set of pre-known single-antenna mobile users (MUs). This part focuses on minimizing the network total power consumption subject to practical constraints. The problems are solved using sophisticated techniques from optimization theory (e.g. Dual Decomposition-based algorithm and the alternating direction method of multipliers (ADMM)-based algorithm). One highlight of this part is that the proposed solutions can be implemented in a distributed fashion by allowing a reasonable information exchange between the coupled clouds. Additionally, feasible solutions of the considered optimization problems can be estimated locally at each iteration. Simulation results show that the proposed distributed algorithms converge to the centralized algorithms in a reasonable number of iterations. To further account of the backhaul congestion due to densification in CRANs, the second part of this thesis considers the downlink of a cache-enabled CRAN where each BS is equipped with a local-cache with limited size used to store the popular files without the need for backhauling. Further, each cache-enabled BS is connected to the cloud via limited capacity backhaul link and can serve a set of pre-known single antenna MUs. This part

  4. Social network media exposure and adolescent eating pathology in Fiji

    Science.gov (United States)

    Becker, Anne E.; Fay, Kristen E.; Agnew-Blais, Jessica; Khan, A. Nisha; Striegel-Moore, Ruth H.; Gilman, Stephen E.

    2011-01-01

    Background Mass media exposure has been associated with an increased risk of eating pathology. It is unknown whether indirect media exposure – such as the proliferation of media exposure in an individual’s social network – is also associated with eating disorders. Aims To test hypotheses that both individual (direct) and social network (indirect) mass media exposures were associated with eating pathology in Fiji. Method We assessed several kinds of mass media exposure, media influence, cultural orientation and eating pathology by self-report among adolescent female ethnic Fijians (n = 523). We fitted a series of multiple regression models of eating pathology, assessed by the Eating Disorder Examination Questionnaire (EDE–Q), in which mass media exposures, sociodemographic characteristics and body mass index were entered as predictors. Results Both direct and indirect mass media exposures were associated with eating pathology in unadjusted analyses, whereas in adjusted analyses only social network media exposure was associated with eating pathology. This result was similar when eating pathology was operationalised as either a continuous or a categorical dependent variable (e.g. odds ratio OR = 1.60, 95% CI 1.15–2.23 relating social network media exposure to upper-quartile EDE–Q scores). Subsequent analyses pointed to individual media influence as an important explanatory variable in this association. Conclusions Social network media exposure was associated with eating pathology in this Fijian study sample, independent of direct media exposure and other cultural exposures. Findings warrant further investigation of its health impact in other populations. PMID:21200076

  5. A Unified Access Model for Interconnecting Heterogeneous Wireless Networks

    Science.gov (United States)

    2015-05-01

    validation of the proposed network design for unified network access, and it lays the foundation for implementing a Software-Defined Networking ( SDN ...testing real-world applications. Most importantly, our simulation serves as a template for implementing a unified MAC layer network using SDN . SDN ...is a network program with a programmable, centralized control plane.4 SDN protocols can be used to mediate access between nodes of an HN. The method

  6. Investigating communication networks contextually: Qualitative network analysis as cross-media research

    Directory of Open Access Journals (Sweden)

    Andreas Hepp

    2016-06-01

    Full Text Available This article introduces the approach of contextualised communication network analysis as a qualitative procedure for researching communicative relationships realised through the media. It combines qualitative interviews on media appropriation, egocentric network maps, and media diaries. Through the triangulation of these methods of data collection, it is possible to gain a differentiated insight into the specific meanings, structures and processes of communication networks across a variety of media. The approach is illustrated using a recent study dealing with the mediatisation of community building among young people. In this context, the qualitative communication network analysis has been applied to distinguish “localists” from “centrists”, “multilocalists”, and “pluralists”. These different “horizons of mediatised communitisation” are connected to distinct communication networks. Since this involves today a variety of different media, the contextual analysis of communication networks necessarily has to imply a cross-media perspective.

  7. Optical-router-based dynamically reconfigurable photonic access network

    NARCIS (Netherlands)

    Roy, R.

    2014-01-01

    The Broadband photonics (BBP) project under the Freeband consortium of projects investigated the design of a dynamically reconfigurable photonic access network. Access networks form a key link in ensuring optimal bandwidth to the end user without which any improvements deeper in the network in the

  8. Analysis and Comparison on Novel Sensor Network Security Access Technology

    Directory of Open Access Journals (Sweden)

    Ping LIU

    2014-01-01

    Full Text Available The article introduces against technical defects of traditional network access control system, detail NAC, NAP, UAC and TNC four kinds of new network security access technology, and this article analyzes and compares them. Security framework for wireless sensor networks SPINS defines the mechanism and algorithm of complete and effective in confidentiality, point-to-point message authentication, integrity, authentication, broadcast authentication.

  9. Models of network access using feedback fluid queues

    NARCIS (Netherlands)

    Mandjes, M.R.H.; Mitra, Debasis; Scheinhardt, Willem R.W.

    At the access to networks, in contrast to the core, distances and feedback delays, as well as link capacities are small, which has network engineering implications that are investigated in this paper. We consider a single point in the access network which multiplexes several bursty users. The users

  10. Models of network access using feedback fluid queues

    NARCIS (Netherlands)

    M.R.H. Mandjes (Michel); D. Mitra; W.R.W. Scheinhardt (Werner)

    2002-01-01

    htmlabstractAt the access to networks, in contrast to the core, distances and feedback delay s, as well as link capacities are small, which has network engineering implications that are investigated in this paper. We consider a single point in the access network which multiplexes several bursty

  11. Radio Access Sharing Strategies for Multiple Operators in Cellular Networks

    DEFF Research Database (Denmark)

    Popovska Avramova, Andrijana; Iversen, Villy Bæk

    2015-01-01

    deployments (required for coverage enhancement), increased base station utilization, and reduced overall power consumption. Today, network sharing in the radio access part is passive and limited to cell sites. With the introduction of Cloud Radio Access Network and Software Defined Networking adoption......Mobile operators are moving towards sharing network capacity in order to reduce capital and operational expenditures, while meeting the increasing demand for mobile broadband data services. Radio access network sharing is a promising technique that leads to reduced number of physical base station...... to the radio access network, the possibility for sharing baseband processing and radio spectrum becomes an important aspect of network sharing. This paper investigates strategies for active sharing of radio access among multiple operators, and analyses the individual benefits depending on the sharing degree...

  12. Quantitative analysis of access strategies to remoteinformation in network services

    DEFF Research Database (Denmark)

    Olsen, Rasmus Løvenstein; Schwefel, Hans-Peter; Hansen, Martin Bøgsted

    2006-01-01

    Remote access to dynamically changing information elements is a required functionality for various network services, including routing and instances of context-sensitive networking. Three fundamentally different strategies for such access are investigated in this paper: (1) a reactive approach in......, network delay characterization) and specific requirements on mismatch probability, traffic overhead, and access delay. Finally, the analysis is applied to the use-case of context-sensitive service discovery....

  13. Media, social networking, and pediatric obesity.

    Science.gov (United States)

    Vandewater, Elizabeth A; Denis, Laurence M

    2011-12-01

    The 5 years leading up to 2011 witnessed unprecedented transformations in the technology and media available to American consumers. These changes have led to major paradigmatic shifts in the way people think about media, how they use it, and the role they expect it to play in their lives. This article discusses the new media landscape and summarizes the evidence regarding media influences on pediatric obesity. Various effects on pediatric obesity are discussed and some conclusions and implications are provided, including possibilities and future directions for clinical practice and research. Copyright © 2011. Published by Elsevier Inc.

  14. Open and Accessible: The Relationship between Closures and Circulation in School Library Media Centers

    Science.gov (United States)

    Dickinson, Gail; Gavigan, Karen; Pribesh, Shana

    2008-01-01

    A hallmark of school library media best practice is for the library media center to be open and accessible to patron use before, during, and after the school day and throughout the entire school year. Anecdotal evidence and informal discussion among school library media specialists indicate that library media facilities are sometimes used for…

  15. The impacts of post-media networks on the traditional media

    Directory of Open Access Journals (Sweden)

    Dr. Francisco Campos Freire

    2008-01-01

    Full Text Available The fast and successful penetration in society of the so-called social networks in the past two or three years has alarmed the traditional media. The new phenomenon reaches a wider audience, enhances advertising, achieves customization, and breaches some of the barriers of traditional media. The new communication channel is used already by millions of Internet users as their main source of information and entertainment. This research paper analyses the structure of eleven global social networks, which feature contents in Spanish and other languages, in relation to the electronic version (e-version of the main Spanish newspapers. The aim is to prove if the so-called social networks are a new type of media, a new platform for social relationships and post-media contents, which look more like the audiovisual media than the traditional newspapers.

  16. Service delivery aspects in a reconfigurable photonic access network

    NARCIS (Netherlands)

    Roy, R.; Manhoudt, Gert; van Etten, Wim

    2008-01-01

    We discuss service delivery aspects in a reconfigurable photonic access network. The network is viewed as a stack of logical PONs in which a DWDM overlay is used over TDM PONs operating in their native format. The use of optical routers in the network allows for a dynamic change in the network

  17. Digital Humanities and networked digital media

    DEFF Research Database (Denmark)

    Finnemann, Niels Ole

    2014-01-01

    This article discusses digital humanities and the growing diversity of digital media, digital materials and digital methods. The first section describes the humanities computing tradition formed around the interpretation of computation as a rule-based process connected to a concept of digital...... of software-supported methods. This is so, in part, because of the complexity of the world and, in part, because digital media remain open to the projection of new epistemologies onto the functional architecture of these media. The third section discusses the heterogeneous character of digital materials...

  18. Signed Link Analysis in Social Media Networks

    OpenAIRE

    Beigi, Ghazaleh; Tang, Jiliang; Liu, Huan

    2016-01-01

    Numerous real-world relations can be represented by signed networks with positive links (e.g., trust) and negative links (e.g., distrust). Link analysis plays a crucial role in understanding the link formation and can advance various tasks in social network analysis such as link prediction. The majority of existing works on link analysis have focused on unsigned social networks. The existence of negative links determines that properties and principles of signed networks are substantially dist...

  19. Broadband Access Network Planning Optimization Considering Real Copper Cable Lengths

    Science.gov (United States)

    Peternel, Blaž Kos, Andrej

    Broadband access network planning strategies with techno-economic calculations are important topics, when optimal broadband network deployments are considered. This paper analyzes optimal deployment combination of digital subscriber line technologies (xDSL) and fiber to the home technologies (FTTx), following different user bandwidth demand scenarios. For this reason, optimal placement of remote digital subscriber line multiplexer (RDSLAM) is examined. Furthermore, the article also discusses the economy of investments, depending on certain investment threshold and the reach of different xDSL technologies. Finally, the difference between broadband network deployment in a characteristic urban and rural area in Republic of Slovenia, in terms of required optical cable dig length per household is shown. A tree structure network model of a traditional copper access network is introduced. A dynamic programming logic, with recursion as a basis of a tree structure examination and evaluation of optimal network elements placement is used. The tree structure network model considers several real network parameters (e. g.: copper cable lengths, user coordinates, node coordinates). The main input for the optimization is a local loop distance between each user and a candidate node for RDSLAM placement. Modelling of copper access networks with a tree structure makes new extensions in planning optimization of broadband access networks. Optimization of network elements placement has direct influence on efficiency and profitability of broadband access telecommunication networks.

  20. A Method for Automated Planning of FTTH Access Network Infrastructures

    DEFF Research Database (Denmark)

    Riaz, Muhammad Tahir; Pedersen, Jens Myrup; Madsen, Ole Brun

    2005-01-01

    In this paper a method for automated planning of Fiber to the Home (FTTH) access networks is proposed. We introduced a systematic approach for planning access network infrastructure. The GIS data and a set of algorithms were employed to make the planning process more automatic. The method explains...

  1. Applications of social media and social network analysis

    CERN Document Server

    Kazienko, Przemyslaw

    2015-01-01

    This collection of contributed chapters demonstrates a wide range of applications within two overlapping research domains: social media analysis and social network analysis. Various methodologies were utilized in the twelve individual chapters including static, dynamic and real-time approaches to graph, textual and multimedia data analysis. The topics apply to reputation computation, emotion detection, topic evolution, rumor propagation, evaluation of textual opinions, friend ranking, analysis of public transportation networks, diffusion in dynamic networks, analysis of contributors to commun

  2. Access network evolution: optical fibre to the subscribers and impact on the metropolitan and home networks

    Science.gov (United States)

    Chanclou, P.; Belfqih, Z.; Charbonnier, B.; Duong, T.; Frank, F.; Genay, N.; Huchard, M.; Guignard, P.; Guillo, L.; Landousies, B.; Pizzinat, A.; Ramanitra, H.; Saliou, F.; Durel, S.; Urvoas, P.; Ouzzif, M.; Le Masson, J.

    2008-11-01

    This article describes broadband optical access network evolution including high speed interfaces for fixed and mobile services. The impact of network access evolution on network architecture and transmission equipment localization on the metropolitan network is also mentioned. Some technical challenges are also discussed, namely concerning the optical extended budget, as well as the impact of access evolution on the metropolitan network. The access bit rate evolution has also an impact on the home network by the necessity of offering connectivity to customers at 1 Gbit/s, for example, over plastic optical fibre. To cite this article: P. Chanclou et al., C. R. Physique 9 (2008).

  3. Effects of network node consolidation in optical access and aggregation networks on costs and power consumption

    Science.gov (United States)

    Lange, Christoph; Hülsermann, Ralf; Kosiankowski, Dirk; Geilhardt, Frank; Gladisch, Andreas

    2010-01-01

    The increasing demand for higher bit rates in access networks requires fiber deployment closer to the subscriber resulting in fiber-to-the-home (FTTH) access networks. Besides higher access bit rates optical access network infrastructure and related technologies enable the network operator to establish larger service areas resulting in a simplified network structure with a lower number of network nodes. By changing the network structure network operators want to benefit from a changed network cost structure by decreasing in short and mid term the upfront investments for network equipment due to concentration effects as well as by reducing the energy costs due to a higher energy efficiency of large network sites housing a high amount of network equipment. In long term also savings in operational expenditures (OpEx) due to the closing of central office (CO) sites are expected. In this paper different architectures for optical access networks basing on state-of-the-art technology are analyzed with respect to network installation costs and power consumption in the context of access node consolidation. Network planning and dimensioning results are calculated for a realistic network scenario of Germany. All node consolidation scenarios are compared against a gigabit capable passive optical network (GPON) based FTTH access network operated from the conventional CO sites. The results show that a moderate reduction of the number of access nodes may be beneficial since in that case the capital expenditures (CapEx) do not rise extraordinarily and savings in OpEx related to the access nodes are expected. The total power consumption does not change significantly with decreasing number of access nodes but clustering effects enable a more energyefficient network operation and optimized power purchase order quantities leading to benefits in energy costs.

  4. Pore network extraction for fractured porous media

    Science.gov (United States)

    Jiang, Z.; van Dijke, M. I. J.; Geiger, S.; Ma, J.; Couples, G. D.; Li, X.

    2017-09-01

    Although flow through fractured rocks involves many different length-scales, it is crucial for the prediction of continuum-scale single- and multi-phase flow functions to understand, at the pore-scale, the interaction between the rock matrix and fractures. Here we present a pore-network extraction method in which the pore diameters and fracture apertures are of similar size. The method involves a shrinking algorithm to extract a hybrid skeleton of medial axes and surfaces, and it includes a workflow to convert the medial surfaces of fractures into dense networks of virtual medial axes, allowing generation of an integrated pore-network for the entire pore space. Appropriate single- and two-phase flow properties are assigned to network elements representing the fractures. We validate the method via comparisons between pore network flow simulations and an analytical solution, direct flow simulations and experimental observations. The network calculations are several orders of magnitude faster than the direct simulations.

  5. Digital Humanities and networked digital media

    Directory of Open Access Journals (Sweden)

    Niels Ole Finnemann

    2014-10-01

    Full Text Available This article discusses digital humanities and the growing diversity of digital media, digital materials and digital methods. The first section describes the humanities computing tradition formed around the interpretation of computation as a rule-based process connected to a concept of digital materials centred on the digitisation of non-digital, finite works, corpora and oeuvres. The second section discusses “the big tent” of contemporary digital humanities. It is argued that there can be no unifying interpretation of digital humanities above the level of studying digital materials with the help of software-supported methods. This is so, in part, because of the complexity of the world and, in part, because digital media remain open to the projection of new epistemologies onto the functional architecture of these media. The third section discusses the heterogeneous character of digital materials and proposes that the study of digital materials should be established as a field in its own right.

  6. Digital Humanities and networked digital media

    Directory of Open Access Journals (Sweden)

    Niels Ole Finnemann

    2014-12-01

    Full Text Available This article discusses digital humanities and the growing diversity of digital media, digital materials and digital methods. The first section describes the humanities computing tradition formed around the interpretation of computation as a rule-based process connected to a concept of digital materials centred on the digitisation of non-digital, finite works, corpora and oeuvres. The second section discusses “the big tent” of contemporary digital humanities. It is argued that there can be no unifying interpretation of digital humanities above the level of studying digital materials with the help of software-supported methods. This is so, in part, because of the complexity of the world and, in part, because digital media remain open to the projection of new epistemologies onto the functional architecture of these media. The third section discusses the heterogeneous character of digital materials and proposes that the study of digital materials should be established as a field in its own right.

  7. Cooperative Media Streaming Using Adaptive Network Compression

    DEFF Research Database (Denmark)

    Møller, Janus Heide; Sørensen, Jesper Hemming; Krigslund, Rasmus

    2008-01-01

    Media content distribution constitutes a growing share of the services on the Internet. Two distinct distribution approaches used today are Layered Coding (LC) and Multiple Description Coding (MDC). Current wireless connection technologies, e.g. Wimax, have properties which make them unsuitable...... for media distribution using traditional approaches. In particular, the asymmetric relationship between the uplink and the downlink bandwidth makes the cooperative distribution difficult. A promising concept, termed MDC with Conditional Compression (MDC-CC), has been proposed [11], which essentially acts...

  8. C-Aware: A Cache Management Algorithm Considering Cache Media Access Characteristic in Cloud Computing

    Directory of Open Access Journals (Sweden)

    Zhu Xudong

    2013-01-01

    Full Text Available Data congestion and network delay are the important factors that affect performance of cloud computing systems. Using local disk of computing nodes as a cache can sometimes get better performance than accessing data through the network. This paper presents a storage cache placement algorithm—C-Aware, which traces history access information of cache and data source, adaptively decides whether to cache data according to cache media characteristic and current access environment, and achieves good performance under different workload on storage server. We implement this algorithm in both simulated and real environments. Our simulation results using OLTP and WebSearch traces demonstrate that C-Aware achieves better adaptability to the changes of server workload. Our benchmark results in real system show that, in the scenario where the size of local cache is half of data set, C-Aware gets nearly 80% improvement compared with traditional methods when the server is not busy and still presents comparable performance when there is high workload on server side.

  9. Securing Social Media : A Network Structure Approach

    NARCIS (Netherlands)

    Chiluka, N.J.

    2013-01-01

    Due to its democratized nature, online social media (OSM) attracts millions of users to publish and share their content with friends as well as a wider audience at little cost. Such a vast user base and a wealth of content, however, presents its own challenges. First, the amount of user-generated

  10. Mass media influence spreading in social networks with community structure

    Science.gov (United States)

    Candia, Julián; Mazzitello, Karina I.

    2008-07-01

    We study an extension of Axelrod's model for social influence, in which cultural drift is represented as random perturbations, while mass media are introduced by means of an external field. In this scenario, we investigate how the modular structure of social networks affects the propagation of mass media messages across a society. The community structure of social networks is represented by coupled random networks, in which two random graphs are connected by intercommunity links. Considering inhomogeneous mass media fields, we study the conditions for successful message spreading and find a novel phase diagram in the multidimensional parameter space. These findings show that social modularity effects are of paramount importance for designing successful, cost-effective advertising campaigns.

  11. The utilization of social networking as promotion media (Case study: Handicraft business in Palembang)

    OpenAIRE

    Rahadi, Dedi Rianto; Abdillah, Leon Andretti

    2013-01-01

    Nowadays social media (Twitter, Facebook, etc.), not only simply as communication media, but also for promotion. Social networking media offers many business benefits for companies and organizations. Research purposes is to determine the model of social network media utilization as a promotional media for handicraft business in Palembang city. Qualitative and quantitative research design are used to know how handicraft business in Palembang city utilizing social media networking as a promotio...

  12. Examining the use of evidence-based and social media supported tools in freely accessible physical activity intervention websites

    OpenAIRE

    Vandelanotte, Corneel; Kirwan, Morwenna; Rebar, Amanda; Alley, Stephanie; Short, Camille; Fallon, Luke; Buzza, Gavin; Schoeppe, Stephanie; Maher, Carol; Duncan, Mitch J

    2014-01-01

    Background It has been shown that physical activity is more likely to increase if web-based interventions apply evidence-based components (e.g. self-monitoring) and incorporate interactive social media applications (e.g. social networking), but it is unclear to what extent these are being utilized in the publicly available web-based physical activity interventions. The purpose of this study was to evaluate whether freely accessible websites delivering physical activity interventions use evide...

  13. Social Media for Networking, Professional Development, and Patient Engagement.

    Science.gov (United States)

    Markham, Merry Jennifer; Gentile, Danielle; Graham, David L

    2017-01-01

    Social media has become an established method of communication, and many physicians are finding these interactive tools and platforms to be useful for both personal and professional use. Risks of social media, or barriers to its use, include perceived lack of time, privacy concerns, and the risk of damage to one's reputation by unprofessional behavior. Of the social media platforms, Twitter has become favored by physicians and other health care professionals. Although one of the most obvious uses of social media is for rapid dissemination and receipt of information, oncologists are finding that social media is important for networking through blogs, Facebook, and Twitter. These platforms also have potential for providing opportunities for professional development, such as finding collaborators through networking, participation in Twitter journal clubs, and participating in online case-based tumor boards. Social media can also be used for patient engagement, such as through participation in tweet chats. There is emerging data that patient engagement through these platforms may lead to improvement in some health-related outcomes; however, data are sparse for oncology-specific outcomes. Efforts are underway to determine how to assess how social media engagement impacts health outcomes in oncology patients.

  14. Access Network Selection Based on Fuzzy Logic and Genetic Algorithms

    Directory of Open Access Journals (Sweden)

    Mohammed Alkhawlani

    2008-01-01

    Full Text Available In the next generation of heterogeneous wireless networks (HWNs, a large number of different radio access technologies (RATs will be integrated into a common network. In this type of networks, selecting the most optimal and promising access network (AN is an important consideration for overall networks stability, resource utilization, user satisfaction, and quality of service (QoS provisioning. This paper proposes a general scheme to solve the access network selection (ANS problem in the HWN. The proposed scheme has been used to present and design a general multicriteria software assistant (SA that can consider the user, operator, and/or the QoS view points. Combined fuzzy logic (FL and genetic algorithms (GAs have been used to give the proposed scheme the required scalability, flexibility, and simplicity. The simulation results show that the proposed scheme and SA have better and more robust performance over the random-based selection.

  15. Designing Broadband Access Networks with Triple Redundancy

    DEFF Research Database (Denmark)

    Pedersen, Jens Myrup; Riaz, Muhammad Tahir; Knudsen, Thomas Phillip

    2005-01-01

    provided by some wireless solution. Based on experience with planning Fiber To The Home, the architecture is designed to meet a number of demands, making it practicable and useful in realworld network planning. The proposed wired topology is planar, and suitable for being fitted onto the road network...... without compromising line independency, and it can be implemented stepwise, the first step being based on a simple ring/tree topology. The double ring is used for the distribution network, ensuring 3-connectivity and making it feasible to use for connecting the base stations of the wireless network...

  16. A Method for Upper Bounding on Network Access Speed

    DEFF Research Database (Denmark)

    Knudsen, Thomas Phillip; Patel, A.; Pedersen, Jens Myrup

    2004-01-01

    This paper presents a method for calculating an upper bound on network access speed growth and gives guidelines for further research experiments and simulations. The method is aimed at providing a basis for simulation of long term network development and resource management.......This paper presents a method for calculating an upper bound on network access speed growth and gives guidelines for further research experiments and simulations. The method is aimed at providing a basis for simulation of long term network development and resource management....

  17. Rural women and violence situation: access and accessibility limits to the healthcare network.

    Science.gov (United States)

    Costa, Marta Cocco da; Silva, Ethel Bastos da; Soares, Joannie Dos Santos Fachinelli; Borth, Luana Cristina; Honnef, Fernanda

    2017-07-13

    To analyze the access and accessibility to the healthcare network of women dwelling in rural contexts undergoing violence situation, as seen from the professionals' speeches. A qualitative, exploratory, descriptive study with professionals from the healthcare network services about coping with violence in four municipalities in the northern region of Rio Grande do Sul. The information derived from interviews, which have been analyzed by thematic modality. (Lack of) information of women, distance, restricted access to transportation, dependence on the partner and (lack of) attention by professionals to welcome women undergoing violence situation and (non)-articulation of the network are factors that limit the access and, as a consequence, they result in the lack of confrontation of this problem. To bring closer the services which integrate the confrontation network of violence against women and to qualify professionals to welcome these situations are factors that can facilitate the access and adhesion of rural women to the services.

  18. 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

  19. User Expectations for Media Sharing Practices in Open Display Networks

    Directory of Open Access Journals (Sweden)

    Rui Jose

    2015-07-01

    Full Text Available Open Display Networks have the potential to allow many content creators to publish their media to an open-ended set of screen displays. However, this raises the issue of how to match that content to the right displays. In this study, we aim to understand how the perceived utility of particular media sharing scenarios is affected by three independent variables, more specifically: (a the locativeness of the content being shared; (b how personal that content is and (c the scope in which it is being shared. To assess these effects, we composed a set of 24 media sharing scenarios embedded with different treatments of our three independent variables. We then asked 100 participants to express their perception of the relevance of those scenarios. The results suggest a clear preference for scenarios where content is both local and directly related to the person that is publishing it. This is in stark contrast to the types of content that are commonly found in public displays, and confirms the opportunity that open displays networks may represent a new media for self-expression. This novel understanding may inform the design of new publication paradigms that will enable people to share media across the display networks.

  20. User Expectations for Media Sharing Practices in Open Display Networks.

    Science.gov (United States)

    Jose, Rui; Cardoso, Jorge C S; Hong, Jason

    2015-07-06

    Open Display Networks have the potential to allow many content creators to publish their media to an open-ended set of screen displays. However, this raises the issue of how to match that content to the right displays. In this study, we aim to understand how the perceived utility of particular media sharing scenarios is affected by three independent variables, more specifically: (a) the locativeness of the content being shared; (b) how personal that content is and (c) the scope in which it is being shared. To assess these effects, we composed a set of 24 media sharing scenarios embedded with different treatments of our three independent variables. We then asked 100 participants to express their perception of the relevance of those scenarios. The results suggest a clear preference for scenarios where content is both local and directly related to the person that is publishing it. This is in stark contrast to the types of content that are commonly found in public displays, and confirms the opportunity that open displays networks may represent a new media for self-expression. This novel understanding may inform the design of new publication paradigms that will enable people to share media across the display networks.

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

    DEFF Research Database (Denmark)

    Wang, Jiayuan; Yan, Ying; Dittmann, Lars

    2013-01-01

    This paper presents a Software Defined Networking (SDN) control plane based on an overlay GMPLS control model. The SDN control platform manages optical core networks (WDM/DWDM networks) and the associated access networks (GPON networks), which makes it possible to gather global information...

  2. Modeling of Bandwidth Aggregation over Heterogeneous Wireless Access Networks

    DEFF Research Database (Denmark)

    Popovska Avramova, Andrijana; Dittmann, Lars

    2012-01-01

    Motivated by the multihomming capability of the mobile devices and the fact that the heterogeneous wireless access networks overlap in coverage, mobile operators are looking for solutions that will benefit by simultaneous use of the available multiple access interfaces. Multipath or multilink...... applications. The analysis is performed on a multipath model developed with OPNET Modeler, which is an advanced research tool that supports modeling and integration of various kinds of built-in networks....

  3. Spatial Tiling and Streaming in an Immersive Media Delivery Network

    NARCIS (Netherlands)

    Niamut, O.A.; Prins, M.J.; Brandenburg, R. van; Havekes, A.

    2011-01-01

    Within the EU FP7 project FascinatE, a capture, production and delivery system capable of supporting pan/tilt/zoom interaction with immersive media is being developed. Intelligent networks with processing components are needed to repurpose the content to suit different device types and framing

  4. Semantic network analysis of vaccine sentiment in online social media.

    Science.gov (United States)

    Kang, Gloria J; Ewing-Nelson, Sinclair R; Mackey, Lauren; Schlitt, James T; Marathe, Achla; Abbas, Kaja M; Swarup, Samarth

    2017-06-22

    To examine current vaccine sentiment on social media by constructing and analyzing semantic networks of vaccine information from highly shared websites of Twitter users in the United States; and to assist public health communication of vaccines. Vaccine hesitancy continues to contribute to suboptimal vaccination coverage in the United States, posing significant risk of disease outbreaks, yet remains poorly understood. We constructed semantic networks of vaccine information from internet articles shared by Twitter users in the United States. We analyzed resulting network topology, compared semantic differences, and identified the most salient concepts within networks expressing positive, negative, and neutral vaccine sentiment. The semantic network of positive vaccine sentiment demonstrated greater cohesiveness in discourse compared to the larger, less-connected network of negative vaccine sentiment. The positive sentiment network centered around parents and focused on communicating health risks and benefits, highlighting medical concepts such as measles, autism, HPV vaccine, vaccine-autism link, meningococcal disease, and MMR vaccine. In contrast, the negative network centered around children and focused on organizational bodies such as CDC, vaccine industry, doctors, mainstream media, pharmaceutical companies, and United States. The prevalence of negative vaccine sentiment was demonstrated through diverse messaging, framed around skepticism and distrust of government organizations that communicate scientific evidence supporting positive vaccine benefits. Semantic network analysis of vaccine sentiment in online social media can enhance understanding of the scope and variability of current attitudes and beliefs toward vaccines. Our study synthesizes quantitative and qualitative evidence from an interdisciplinary approach to better understand complex drivers of vaccine hesitancy for public health communication, to improve vaccine confidence and vaccination coverage

  5. Network accessibility & the evoluation of urban employment.

    Science.gov (United States)

    2011-06-01

    This research examines the impact of accessibility on the growth of employment centers in the : Los Angeles Region between 1980 and 2000. There is extensive empirical documentation of : polycentricity the presence of multiple concentrations of em...

  6. Beyond Access and Exposure: Implications of Sneaky Media Use for Preschoolers' Sleep Behavior.

    Science.gov (United States)

    Moorman, Jessica D; Harrison, Kristen

    2018-01-09

    Greater consumption of and access to screen media are known correlates of unhealthy sleep behavior in preschoolers. What remains unknown, however, is the role a child's media use plays in this association. Parents and guardians of U.S. preschoolers (N = 278, average child age 56 months) provided information about their child's nightly duration of sleep, daily duration of nap, quantity of screen media use, sneaky media use, and the presence of a screen media device in the bedroom. We assessed four media: television, DVD/VCRs, video games, and computer/Internet. Based on rationales of sleep displacement, the forbidden fruit hypothesis, and social cognitive theory, we predicted that increased consumption of and access to media, along with sneaky media use, would predict a shorter duration of nightly sleep and longer duration of daily nap across the four screen media. In correlational analyses, a clear pattern emerged with quantity of media use, screen media in the bedroom, and sneaky media use associated with shorter nightly duration of sleep and longer duration of daily nap. In regression analyses, only weekday evening television viewing and sneaky media use predicted shorter nightly sleep duration; weekend morning and evening DVD use predicted longer naps.

  7. Security Issues in Networks with Internet Access

    National Research Council Canada - National Science Library

    Landwehr, Carl E; Goldschlag, David M

    1997-01-01

    .... The principles are illustrated by describing the security issues a hypothetical company faces as the networks that support its operations evolve from strictly private, through a mix of Internet...

  8. Approximate Networking for Universal Internet Access

    National Research Council Canada - National Science Library

    Junaid Qadir; Arjuna Sathiaseelan; Umar Bin Farooq; Muhammad Usama; Muhammad Ali Imran; Muhammad Shafique

    2017-01-01

    Despite the best efforts of networking researchers and practitioners, an ideal Internet experience is inaccessible to an overwhelming majority of people the world over, mainly due to the lack of cost...

  9. Analytical Modeling of Medium Access Control Protocols in Wireless Networks

    Science.gov (United States)

    2006-03-01

    Imperatives and chal- lenges. Ad Hoc Networks, 1(1):13–64, July 2003. [28] I. Chlamtac and A. Faragó. Making transmission schedules immune to topology changes...P. Karn. MACA - a new channel access method for packet radio. In ARRL/CRRL Amateur Radio 9th Computer Networking Conference, pages 134–140, 1990

  10. Robust and Flexible Wavelength Division Multiplexed Optical Access Networks

    DEFF Research Database (Denmark)

    Wagner, Christoph; Eiselt, Michael; Grobe, Klaus

    Future wavelength division multiplexed (WDM) access networks should be as flexible as possible. One flexibility is port wavelength-agnosticism at the optical network unit (ONU) interface, achieved via tunable laser. At the same time such systems needs to be robust against crosstalk impairments...

  11. Discrete Network Modeling for Field-Scale Flow and Transport Through Porous Media

    National Research Council Canada - National Science Library

    Howington, Stacy

    1997-01-01

    .... Specifically, a stochastic, high-resolution, discrete network model is developed and explored for simulating macroscopic flow and conservative transport through macroscopic porous media Networks...

  12. Learning for Work and Professional Development: The Significance of Informal Learning Networks of Digital Media Industry Professionals

    Science.gov (United States)

    Campana, Joe

    2014-01-01

    Informal learning networks play a key role in the skill and professional development of professionals, working in micro-businesses within Australia's digital media industry, as they do not have access to learning and development or human resources sections that can assist in mapping their learning pathway. Professionals working in this environment…

  13. Greening radio access networks using distributed base station architectures

    DEFF Research Database (Denmark)

    Kardaras, Georgios; Soler, José; Dittmann, Lars

    2010-01-01

    . However besides this, increasing energy efficiency represents a key factor for reducing operating expenses and deploying cost effective mobile networks. This paper presents how distributed base station architectures can contribute in greening radio access networks. More specifically, the advantages...... energy saving. Different subsystems have to be coordinated real-time and intelligent network nodes supporting complicated functionalities are necessary. Distributed base station architectures are ideal for this purpose mainly because of their high degree of configurability and self...

  14. Social network in patient safety: Social media visibility

    Directory of Open Access Journals (Sweden)

    Azucena Santillán García

    2011-11-01

    Full Text Available Internet social network (social media is a powerful communication tool, and its use is expanding significantly. This paper seeks to know the current state of visibility in online social networks of active citizen talking about patient safety. This is an observational cross-sectional study whose target population is the websites Facebook, Twitter and Tuenti in Spain. By three consecutive cuts social profiles were found using the searching terms “seguridad+paciente” and “safety+patient”. There were found 5 profiles on Facebook that met the search criteria, 6 on Twitter and none were found on Tuenti. It is concluded that although there is evidence of the rise of social networking, citizen network involved in patient safety appears not to be significantly represented within the social networks examined.

  15. USE AND USE INTENSITY OF SOCIAL MEDIA NETWORKING SYSTEMS BY NIGERIAN AGRO-ENTREPRENEURS

    Directory of Open Access Journals (Sweden)

    Joseph Omotoso AJAYI

    2015-04-01

    Full Text Available Agro-entrepreneurs are key to the Nigerian economy as they constitute the majority of the work force, providing food and employment opportunities for more than 60% of the largest black nation on earth. Nigeria’s social media networking system which is the largest in Africa has got its usefulness in many conventional and contemporary applications in the recent times. Social media has become the fastest, cheapest and unrestricted communication and marketing tool of this jet age. This study therefore focused on the use and use intensity of social media networking systems by Nigerian agro-entrepreneurs. The study made use of mainly primary data. Primary data were collected with the aid of well-structured questionnaires assisted with interview schedules. Field data collection was conducted between June and September, 2014. Multi-stage sampling technique was used to select three hundred and sixty (360 respondents across the three (3 highly ICT compliant states (Lagos, Ondo and Oyo. Data collected were analysed using descriptive statistics and multiple regression model. The results of the regression model indicate that education, availability of power supply and customer base of the agro-entrepreneurs positively influenced use intensity of social media by the agro-entrepreneurs while age and cost of access data negatively influenced their use intensity of social media.

  16. Reliability Demands in FTTH Access Networks

    DEFF Research Database (Denmark)

    Pedersen, Jens Myrup; Knudsen, Thomas Phillip; Madsen, Ole Brun

    2004-01-01

    In this paper reliability and bandwidth demands of existing, new and expected classes of applications running over Fiber To The Home (FTTH) networks to private users and small enterprises are analyzed and discussed. Certain applications such as home security and telemedicine are likely to require...

  17. Reliability Demands in FTTH Access Networks

    DEFF Research Database (Denmark)

    Pedersen, Jens Myrup; Knudsen, Thomas Phillip; Madsen, Ole Brun

    2005-01-01

    In this paper reliability and bandwidth demands of existing, new and expected classes of applications running over Fiber To The Home (FTTH) networks to private users and small enterprises are analysed and discussed. Certain applications such as home security and telemedicine are likely to require...

  18. Feasibility of using existing open access networks to support the harmonization of open access

    OpenAIRE

    Linde, Peter; Wessels, Bridgette; Smallwood, Rod; Price, Lada; Noorman, Merel; Wyatt, Sally; Sondervan, Jeroen

    2015-01-01

    In this report we identify and assess different options for bringing together and mobilizing relevant stakeholders in the open access arena. This builds on previous work done in the RECODE project about the open access stakeholder ecosystem, the barriers and the enablers for open access to research data as well as on the RECODE overarching policy recommendations set out in the RECODE work package 5. We have identified a sample of existing networks and organizations to determine whether they a...

  19. Opinion dynamics on interacting networks: media competition and social influence

    Science.gov (United States)

    Quattrociocchi, Walter; Caldarelli, Guido; Scala, Antonio

    2014-01-01

    The inner dynamics of the multiple actors of the informations systems – i.e, T.V., newspapers, blogs, social network platforms, – play a fundamental role on the evolution of the public opinion. Coherently with the recent history of the information system (from few main stream media to the massive diffusion of socio-technical system), in this work we investigate how main stream media signed interaction might shape the opinion space. In particular we focus on how different size (in the number of media) and interaction patterns of the information system may affect collective debates and thus the opinions' distribution. We introduce a sophisticated computational model of opinion dynamics which accounts for the coexistence of media and gossip as separated mechanisms and for their feedback loops. The model accounts also for the effect of the media communication patterns by considering both the simple case where each medium mimics the behavior of the most successful one (to maximize the audience) and the case where there is polarization and thus competition among media memes. We show that plurality and competition within information sources lead to stable configurations where several and distant cultures coexist. PMID:24861995

  20. Opinion dynamics on interacting networks: media competition and social influence.

    Science.gov (United States)

    Quattrociocchi, Walter; Caldarelli, Guido; Scala, Antonio

    2014-05-27

    The inner dynamics of the multiple actors of the informations systems - i.e, T.V., newspapers, blogs, social network platforms, - play a fundamental role on the evolution of the public opinion. Coherently with the recent history of the information system (from few main stream media to the massive diffusion of socio-technical system), in this work we investigate how main stream media signed interaction might shape the opinion space. In particular we focus on how different size (in the number of media) and interaction patterns of the information system may affect collective debates and thus the opinions' distribution. We introduce a sophisticated computational model of opinion dynamics which accounts for the coexistence of media and gossip as separated mechanisms and for their feedback loops. The model accounts also for the effect of the media communication patterns by considering both the simple case where each medium mimics the behavior of the most successful one (to maximize the audience) and the case where there is polarization and thus competition among media memes. We show that plurality and competition within information sources lead to stable configurations where several and distant cultures coexist.

  1. Opinion dynamics on interacting networks: media competition and social influence

    Science.gov (United States)

    Quattrociocchi, Walter; Caldarelli, Guido; Scala, Antonio

    2014-05-01

    The inner dynamics of the multiple actors of the informations systems - i.e, T.V., newspapers, blogs, social network platforms, - play a fundamental role on the evolution of the public opinion. Coherently with the recent history of the information system (from few main stream media to the massive diffusion of socio-technical system), in this work we investigate how main stream media signed interaction might shape the opinion space. In particular we focus on how different size (in the number of media) and interaction patterns of the information system may affect collective debates and thus the opinions' distribution. We introduce a sophisticated computational model of opinion dynamics which accounts for the coexistence of media and gossip as separated mechanisms and for their feedback loops. The model accounts also for the effect of the media communication patterns by considering both the simple case where each medium mimics the behavior of the most successful one (to maximize the audience) and the case where there is polarization and thus competition among media memes. We show that plurality and competition within information sources lead to stable configurations where several and distant cultures coexist.

  2. Social media networking in pediatric hydrocephalus: a point-prevalence analysis of utilization.

    Science.gov (United States)

    Elkarim, Ghassan Awad; Alotaibi, Naif M; Samuel, Nardin; Wang, Shelly; Ibrahim, George M; Fallah, Aria; Weil, Alexander G; Kulkarni, Abhaya V

    2017-08-01

    OBJECTIVE A recent survey has shown that caregivers of children with shunt-treated hydrocephalus frequently use social media networks for support and information gathering. The objective of this study is to describe and assess social media utilization among users interested in hydrocephalus. METHODS Publicly accessible accounts and videos dedicated to the topic of hydrocephalus were comprehensively searched across 3 social media platforms (Facebook, Twitter, and YouTube) throughout March 2016. Summary statistics were calculated on standard metrics of social media popularity. A categorization framework to describe the purpose of pages, groups, accounts, channels, and videos was developed following the screening of 100 titles. Categorized data were analyzed using nonparametric tests for statistical significance. RESULTS The authors' search identified 30 Facebook pages, 213 Facebook groups, 17 Twitter accounts, and 253 YouTube videos. These platforms were run by patients, caregivers, nonprofit foundations, and patient support groups. Most accounts were from the United States (n = 196), followed by the United Kingdom (n = 31), Canada (n = 17), India (n = 15), and Germany (n = 12). The earliest accounts were created in 2007, and a peak of 65 new accounts were created in 2011. The total number of users in Facebook pages exceeded those in Facebook groups (p media use in the topic of hydrocephalus. Users interested in hydrocephalus seek privacy for support communications and are attracted to treatment procedure and surgical products videos. These findings provide insight into potential avenues of hydrocephalus outreach, support, or advocacy in social media.

  3. Recommending access control decisions to social media users

    OpenAIRE

    Misra, Gaurav

    2017-01-01

    Social media has become an integral part of the Internet and has revolutionized interpersonal communication. The lines of separation between content creators and content consumers have blurred as normal users have platforms such as social media sites, blogs and microblogs at their disposal on which they can create and consume content as well as have the opportunity to interact with other users. This change has also led to several well documented privacy problems for the users. The privacy pro...

  4. Access Denied: School Librarians' Responses to School District Policies on the Use of Social Media Tools

    Science.gov (United States)

    DiScala, Jeffrey; Weeks, Ann Carlson

    2013-01-01

    Public school districts often block access to online social media tools. While considered a preventive measure to ensure student safety and limit district liability, this policy strips school librarians and their collaborating teachers of opportunities to instruct students in using social media tools creatively and responsibly. Using one school…

  5. The Role of Social Media Tools: Accessible Tourism for Disabled Citizens

    Science.gov (United States)

    Altinay, Zehra; Saner, Tulen; Bahçelerli, Nesrin M.; Altinay, Fahriye

    2016-01-01

    Knowledge sharing becomes important to accomplish digital citizenship. Social media tools become popular to share and diffuse the knowledge in the digitalization. This social media learning and knowledge sharing platforms provides accessibility to the services within societies especially for disabled citizens. This research study aims to evaluate…

  6. Fast Distributed Dynamics of Semantic Networks via Social Media

    Directory of Open Access Journals (Sweden)

    Facundo Carrillo

    2015-01-01

    Full Text Available We investigate the dynamics of semantic organization using social media, a collective expression of human thought. We propose a novel, time-dependent semantic similarity measure (TSS, based on the social network Twitter. We show that TSS is consistent with static measures of similarity but provides high temporal resolution for the identification of real-world events and induced changes in the distributed structure of semantic relationships across the entire lexicon. Using TSS, we measured the evolution of a concept and its movement along the semantic neighborhood, driven by specific news/events. Finally, we showed that particular events may trigger a temporary reorganization of elements in the semantic network.

  7. Social Media Use and Access to Digital Technology in US Young Adults in 2016.

    Science.gov (United States)

    Villanti, Andrea C; Johnson, Amanda L; Ilakkuvan, Vinu; Jacobs, Megan A; Graham, Amanda L; Rath, Jessica M

    2017-06-07

    In 2015, 90% of US young adults with Internet access used social media. Digital and social media are highly prevalent modalities through which young adults explore identity formation, and by extension, learn and transmit norms about health and risk behaviors during this developmental life stage. The purpose of this study was to provide updated estimates of social media use from 2014 to 2016 and correlates of social media use and access to digital technology in data collected from a national sample of US young adults in 2016. Young adult participants aged 18-24 years in Wave 7 (October 2014, N=1259) and Wave 9 (February 2016, N=989) of the Truth Initiative Young Adult Cohort Study were asked about use frequency for 11 social media sites and access to digital devices, in addition to sociodemographic characteristics. Regular use was defined as using a given social media site at least weekly. Weighted analyses estimated the prevalence of use of each social media site, overlap between regular use of specific sites, and correlates of using a greater number of social media sites regularly. Bivariate analyses identified sociodemographic correlates of access to specific digital devices. In 2014, 89.42% (weighted n, 1126/1298) of young adults reported regular use of at least one social media site. This increased to 97.5% (weighted n, 965/989) of young adults in 2016. Among regular users of social media sites in 2016, the top five sites were Tumblr (85.5%), Vine (84.7%), Snapchat (81.7%), Instagram (80.7%), and LinkedIn (78.9%). Respondents reported regularly using an average of 7.6 social media sites, with 85% using 6 or more sites regularly. Overall, 87% of young adults reported access or use of a smartphone with Internet access, 74% a desktop or laptop computer with Internet access, 41% a tablet with Internet access, 29% a smart TV or video game console with Internet access, 11% a cell phone without Internet access, and 3% none of these. Access to all digital devices with

  8. An evaluation of Access Tier local area network switches.

    Energy Technology Data Exchange (ETDEWEB)

    Eldridge, John M.; Olsberg, Ronald R.

    2004-06-01

    This reports tabulates the Test and Evaluation results of the Access Class Switch tests conducted by members of Department 9336. About 15 switches were reviewed for use in the enterprise network as access tier switches as defined in a three tier architecture. The Access Switch Tier has several functions including: aggregate customer desktop ports, preserve and apply QoS tags, provide switched LAN access, provide VLAN assignment, as well as others. The typical switch size is 48 or less user ports. The evaluation team reviewed network switch evaluation reports from the Tolly Group as well as other sources. We then used these reports as a starting point to identify particular switches for evaluation. In general we reviewed the products of dominant equipment manufacturers. Also, based on architectural design requirements, the majority of the switches tested were of relatively small monolithic unit variety.

  9. How social network heterogeneity facilitates lexical access and lexical prediction.

    Science.gov (United States)

    Lev-Ari, Shiri; Shao, Zeshu

    2017-04-01

    People learn language from their social environment. As individuals differ in their social networks, they might be exposed to input with different lexical distributions, and these might influence their linguistic representations and lexical choices. In this article we test the relation between linguistic performance and 3 social network properties that should influence input variability, namely, network size, network heterogeneity, and network density. In particular, we examine how these social network properties influence lexical prediction, lexical access, and lexical use. To do so, in Study 1, participants predicted how people of different ages would name pictures, and in Study 2 participants named the pictures themselves. In both studies, we examined how participants' social network properties related to their performance. In Study 3, we ran simulations on norms we collected to see how age variability in one's network influences the distribution of different names in the input. In all studies, network age heterogeneity influenced performance leading to better prediction, faster response times for difficult-to-name items, and less entropy in input distribution. These results suggest that individual differences in social network properties can influence linguistic behavior. Specifically, they show that having a more heterogeneous network is associated with better performance. These results also show that the same factors influence lexical prediction and lexical production, suggesting the two might be related.

  10. Auction pricing of network access for North American railways

    DEFF Research Database (Denmark)

    Harrod, Steven

    2013-01-01

    The question of pricing train paths for "open access" railway networks in North America is discussed. An auction process is suggested as necessary to maintain transparency in the contracting process. Multiple random samples of auction pricing for a single track railway line demonstrate that the i......The question of pricing train paths for "open access" railway networks in North America is discussed. An auction process is suggested as necessary to maintain transparency in the contracting process. Multiple random samples of auction pricing for a single track railway line demonstrate...

  11. Outward Accessibility in Urban Street Networks: Characterization and Improvements

    OpenAIRE

    Travençolo, Bruno Augusto Nassif; Costa, Luciano da Fontoura

    2008-01-01

    The dynamics of transportation through towns and cities is strongly affected by the topology of the connections and routes. The current work describes an approach combining complex networks and self-avoiding random walk dynamics in order to quantify in objective and accurate manner, along a range of spatial scales, the accessibility of places in towns and cities. The transition probabilities are estimated for several lengths of the walks and used to calculate the outward accessibility of each...

  12. Social media as a means to access millennial wine consumers

    OpenAIRE

    R. Fuentes Fernández; Vriesekoop, F.; Urbano, B.; Bruwer, J.

    2017-01-01

    Purpose \\ud The purpose of this research is to gain insights of\\ud the use of social media (SM) in the wine industry. From the theoretical viewpoint to analyze wineries’ social media segmentation, targeting and positioning (STP) to help the wine industry to improve the effectiveness of SM communication. \\ud Design/methodology/approach \\ud An observational study of Spanish wineries’ SM presence and traffic was carried out during a three-month period in 2013 and repeated in 2016. During this pe...

  13. Scheduling Data Access in Smart Grid Networks Utilizing Context Information

    DEFF Research Database (Denmark)

    Findrik, Mislav; Grønbæk, Jesper; Olsen, Rasmus Løvenstein

    2014-01-01

    managing this fast flexibility requires two-way data exchange between a controller and sensors/meters via communication networks. In this paper we investigated scheduling of data collection utilizing meta-data from sensors that are describing dynamics of information. We show the applicability...... of this approach for a constraint communication networks of the smart grid and compared three general data access mechanisms, namely, push, pull and event-based....

  14. A Survey of Access Control Models in Wireless Sensor Networks

    Directory of Open Access Journals (Sweden)

    Htoo Aung Maw

    2014-06-01

    Full Text Available Wireless sensor networks (WSNs have attracted considerable interest in the research community, because of their wide range of applications. However, due to the distributed nature of WSNs and their deployment in remote areas, these networks are vulnerable to numerous security threats that can adversely affect their proper functioning. Resource constraints in sensor nodes mean that security mechanisms with a large overhead of computation and communication are impractical to use in WSNs; security in sensor networks is, therefore, a challenge. Access control is a critical security service that offers the appropriate access privileges to legitimate users and prevents illegitimate users from unauthorized access. However, access control has not received much attention in the context of WSNs. This paper provides an overview of security threats and attacks, outlines the security requirements and presents a state-of-the-art survey on access control models, including a comparison and evaluation based on their characteristics in WSNs. Potential challenging issues for access control schemes in WSNs are also discussed.

  15. Proposal of using wireless optical mesh networks and integrated VDSL for broadband access networks

    Science.gov (United States)

    Zhang, Jinlong

    2001-11-01

    The proposal addresses the wireless optical broadband access networks architecture by deploying mesh network structure, which could be the alternatives to FTTx (home or node, etc) architecture. Instead of fiber used as the transmission medium in the distribution plant, here we suggest to use the free space optic links to construct the optical mesh network. The practical connections are depending on the services provided. For Video-on-Demand (VoD) service, the final connection could use twisted pair by integrated VDSL technology. The distributed bandwidth can reach 25-32 Mbps per end user. In this paper we give some comments for designing a broadband access network using optical mesh network structure. It includes the traffic estimation, transmission network design and access node design suggestions.

  16. Media access and reliability for forest conservation support ...

    African Journals Online (AJOL)

    This study therefore reports the media in use or that could be employed to effectively keep Anambra State residents' abreast on environmental amelioration issues. The study employed multistage stratified random sampling technique where the state was stratified into three senatorial districts. One local government area ...

  17. Enabling Access to Digital Media for the Profoundly Disabled Project

    Data.gov (United States)

    National Aeronautics and Space Administration — The system proposed in this effort will allow the handicapped individual with hand/arm motor impairment to use the computer and access digital libraries on the...

  18. Spectrum access and management for cognitive radio networks

    CERN Document Server

    2017-01-01

    This book presents cutting-edge research contributions that address various aspects of network design, optimization, implementation, and application of cognitive radio technologies. It demonstrates how to make better utilization of the available spectrum, cognitive radios and spectrum access to achieve effective spectrum sharing between licensed and unlicensed users. The book provides academics and researchers essential information on current developments and future trends in cognitive radios for possible integration with the upcoming 5G networks. In addition, it includes a brief introduction to cognitive radio networks for newcomers to the field.

  19. Modified network simulation model with token method of bus access

    Directory of Open Access Journals (Sweden)

    L.V. Stribulevich

    2013-08-01

    Full Text Available Purpose. To study the characteristics of the local network with the marker method of access to the bus its modified simulation model was developed. Methodology. Defining characteristics of the network is carried out on the developed simulation model, which is based on the state diagram-layer network station with the mechanism of processing priorities, both in steady state and in the performance of control procedures: the initiation of a logical ring, the entrance and exit of the station network with a logical ring. Findings. A simulation model, on the basis of which can be obtained the dependencies of the application the maximum waiting time in the queue for different classes of access, and the reaction time usable bandwidth on the data rate, the number of network stations, the generation rate applications, the number of frames transmitted per token holding time, frame length was developed. Originality. The technique of network simulation reflecting its work in the steady condition and during the control procedures, the mechanism of priority ranking and handling was proposed. Practical value. Defining network characteristics in the real-time systems on railway transport based on the developed simulation model.

  20. Access, fronthaul and backhaul networks for 5G and beyond

    CERN Document Server

    Imran, Muhammad Ali; Shakir, Muhammad Zeeshan

    2017-01-01

    This book provides an overview from both academic and industrial stakeholders of innovative backhaul/fronthaul solutions, covering a wide spectrum of underlying themes ranging from the recent thrust in edge caching for backhaul relaxation to mmWave based fronthauling for radio access networks.

  1. Requirements and Algorithms for Cooperation of Heterogeneous Radio Access Networks

    DEFF Research Database (Denmark)

    Mihovska, Albena D.; Tragos, Elias; Mino, Emilio

    2009-01-01

    This paper defines the requirements for cooperation of heterogeneous radio access networks (RANs) and proposes a novel radio resource management (RRM) framework for support of mobility and quality of service (QoS) in a heterogeneous communication environment comprising IMT-Advanced and legacy...

  2. Random Access with Physical-layer Network Coding

    NARCIS (Netherlands)

    Goseling, J.; Gastpar, M.C.; Weber, J.H.

    2013-01-01

    Leveraging recent progress in compute-and-forward we propose an approach to random access that is based on physical-layer network coding: When packets collide, it is possible to recover a linear combination of the packets at the receiver. Over many rounds of transmission, the receiver can thus

  3. Ubiquitous access control and policy management in personal networks

    DEFF Research Database (Denmark)

    Kyriazanos, Dimitris M.; Stassinopoulos, George I.; Prasad, Neeli R.

    2006-01-01

    In this paper the authors present the challenges for enabling Security Policies Management and subsequent Ubiquitous Access Control on the Personal Network (PN) environment. A solution based on Security Profiles is proposed, supporting both partially distributed architectures-having in this case...

  4. Network Asymmetries and Access Pricing in Cellular Telecommunications

    NARCIS (Netherlands)

    V. Kocsis

    2005-01-01

    textabstractNetwork shares and retail prices are not symmetric in the telecommunications market with multiple bottlenecks which give rise to new questions of access fee regulation. In this paper we consider a model with two types of asymmetry arising from different entry timing, i.e. a larger

  5. Adaptive spectrum decision framework for heterogeneous dynamic spectrum access networks

    CSIR Research Space (South Africa)

    Masonta, M

    2015-09-01

    Full Text Available Spectrum decision is the ability of a cognitive radio (CR) system to select the best available spectrum band to satisfy dynamic spectrum access network (DSAN) users¿ quality of service (QoS) requirements without causing harmful interference...

  6. Knowledge in Access in Rural Interconnected Areas Network Phase ...

    International Development Research Centre (IDRC) Digital Library (Canada)

    This project provides support for the Knowledge Access in Rural Interconnected Areas Network (KariaNet). Phases I and II ran from 2004 to 2013. The goal of Phase III is to mainstream knowledge management and sharing on local food systems to enable rural and agricultural development professionals to improve project ...

  7. High Dimensional Modulation and MIMO Techniques for Access Networks

    DEFF Research Database (Denmark)

    Binti Othman, Maisara

    Exploration of advanced modulation formats and multiplexing techniques for next generation optical access networks are of interest as promising solutions for delivering multiple services to end-users. This thesis addresses this from two different angles: high dimensionality carrierless amplitudep...... wired-wireless access networks....... the capacity per wavelength of the femto-cell network. Bit rate up to 1.59 Gbps with fiber-wireless transmission over 1 m air distance is demonstrated. The results presented in this thesis demonstrate the feasibility of high dimensionality CAP in increasing the number of dimensions and their potentially...... to be utilized for multiple service allocation to different users. MIMO multiplexing techniques with OFDM provides the scalability in increasing spectral efficiency and bit rates for RoF systems. High dimensional CAP and MIMO multiplexing techniques are two promising solutions for supporting wired and hybrid...

  8. On the Need of Novel Medium Access Control Schemes for Network Coding enabled Wireless Mesh Networks

    DEFF Research Database (Denmark)

    Paramanathan, Achuthan; Pahlevani, Peyman; Roetter, Daniel Enrique Lucani

    2013-01-01

    This paper advocates for a new Medium Access Control (MAC) strategy for wireless meshed networks by identifying overload scenarios in order to provide additional channel access priority to the relay. The key behind our MAC protocol is that the relay will adjust its back off window size according...... that network coding will improve the throughput in such systems, but our novel medium access scheme improves the performance in the cross topology by another 66 % for network coding and 150 % for classical forwarding in theory. These gains translate in a theoretical gain of 33 % of network coding over...... classical forwarding when both systems implement the improved MAC. However, our measurement results show an even larger gain for network coding, namely, up to 65 % over forwarding, as it copes better with channel losses under high load scenarios....

  9. A news media analysis of economic sanction effects on access to medicine in Iran

    Science.gov (United States)

    Kheirandish, Mehrnaz; Rashidian, Arash; Bigdeli, Maryam

    2015-01-01

    Objective: In the past decades economic sanctions have been used by different countries or international organizations in order to deprive target countries of some transactions. While the sanctions do not target health care systems or public health structures, they may, in fact, affect the availability of health care in target countries. In this study, we used media analysis to assess the impacts of recent sanctions imposed by the Central Bank of Iran in 2012 on access to medicines in Iran. Methods: We searched different sources of written news media including a database of nonspecialized weeklies and magazines, online news sources, web pages of daily newspapers and healthcare oriented weeklies from 2011 to 2013. We searched the sources using the general term “medicine” to reduce the chances of missing relevant items. The identified news media were read, and categorized under three groups of items announcing “shortage of medicines,” “medicines related issues” and “no shortage.” We conducted trend analyzes to see whether the news media related to access to medicines were affected by the economic sanctions. Findings: A total number of 371 relevant news media were collected. The number of news media related to medicines substantially increased in the study period: 30 (8%), 161 (43%) and 180 (49%) were published in 2011, 2012 and 2013, respectively. While 145 (39%) of media items referred to the shortage of medicines, 97 (26%) reported no shortage or alleviating of concerns. Conclusion: Media analysis suggests a clear increase in the number of news media reporting a shortage in Iran after the sanctions. In 2013, there were accompanying increases in the number of news media reporting alleviation of the shortages of medicines. Our analysis provides evidence of negative effects of the sanctions on access to medicines in Iran. PMID:26645026

  10. A news media analysis of economic sanction effects on access to medicine in Iran.

    Science.gov (United States)

    Kheirandish, Mehrnaz; Rashidian, Arash; Bigdeli, Maryam

    2015-01-01

    In the past decades economic sanctions have been used by different countries or international organizations in order to deprive target countries of some transactions. While the sanctions do not target health care systems or public health structures, they may, in fact, affect the availability of health care in target countries. In this study, we used media analysis to assess the impacts of recent sanctions imposed by the Central Bank of Iran in 2012 on access to medicines in Iran. We searched different sources of written news media including a database of nonspecialized weeklies and magazines, online news sources, web pages of daily newspapers and healthcare oriented weeklies from 2011 to 2013. We searched the sources using the general term "medicine" to reduce the chances of missing relevant items. The identified news media were read, and categorized under three groups of items announcing "shortage of medicines," "medicines related issues" and "no shortage." We conducted trend analyzes to see whether the news media related to access to medicines were affected by the economic sanctions. A total number of 371 relevant news media were collected. The number of news media related to medicines substantially increased in the study period: 30 (8%), 161 (43%) and 180 (49%) were published in 2011, 2012 and 2013, respectively. While 145 (39%) of media items referred to the shortage of medicines, 97 (26%) reported no shortage or alleviating of concerns. Media analysis suggests a clear increase in the number of news media reporting a shortage in Iran after the sanctions. In 2013, there were accompanying increases in the number of news media reporting alleviation of the shortages of medicines. Our analysis provides evidence of negative effects of the sanctions on access to medicines in Iran.

  11. Framing access to medicines in developing countries: an analysis of media coverage of Canada's Access to Medicines Regime

    Directory of Open Access Journals (Sweden)

    Cosio Andrea

    2010-01-01

    Full Text Available Abstract Background In September 2003, the Canadian government committed to developing legislation that would facilitate greater access to affordable medicines for developing countries. Over the course of eight months, the legislation, now known as Canada's Access to Medicines Regime (CAMR, went through a controversial policy development process and the newspaper media was one of the major venues in which the policy debates took place. The purpose of this study was to examine how the media framed CAMR to determine how policy goals were conceptualized, which stakeholder interests controlled the public debate and how these variables related to the public policy process. Methods We conducted a qualitative content analysis of newspaper coverage of the CAMR policy and implementation process from 2003-2008. The primary theoretical framework for this study was framing theory. A total of 90 articles from 11 Canadian newspapers were selected for inclusion in our analysis. A team of four researchers coded the articles for themes relating to access to medicines and which stakeholders' voice figured more prominently on each issue. Stakeholders examined included: the research-based industry, the generic industry, civil society, the Canadian government, and developing country representatives. Results The most frequently mentioned themes across all documents were the issues of drug affordability, intellectual property, trade agreements and obligations, and development. Issues such as human rights, pharmaceutical innovation, and economic competitiveness got little media representation. Civil society dominated the media contents, followed far behind by the Canadian government, the research-based and generic pharmaceutical industries. Developing country representatives were hardly represented in the media. Conclusions Media framing obscured the discussion of some of the underlying policy goals in this case and failed to highlight issues which are now significant

  12. Framing access to medicines in developing countries: an analysis of media coverage of Canada's Access to Medicines Regime

    Science.gov (United States)

    2010-01-01

    Background In September 2003, the Canadian government committed to developing legislation that would facilitate greater access to affordable medicines for developing countries. Over the course of eight months, the legislation, now known as Canada's Access to Medicines Regime (CAMR), went through a controversial policy development process and the newspaper media was one of the major venues in which the policy debates took place. The purpose of this study was to examine how the media framed CAMR to determine how policy goals were conceptualized, which stakeholder interests controlled the public debate and how these variables related to the public policy process. Methods We conducted a qualitative content analysis of newspaper coverage of the CAMR policy and implementation process from 2003-2008. The primary theoretical framework for this study was framing theory. A total of 90 articles from 11 Canadian newspapers were selected for inclusion in our analysis. A team of four researchers coded the articles for themes relating to access to medicines and which stakeholders' voice figured more prominently on each issue. Stakeholders examined included: the research-based industry, the generic industry, civil society, the Canadian government, and developing country representatives. Results The most frequently mentioned themes across all documents were the issues of drug affordability, intellectual property, trade agreements and obligations, and development. Issues such as human rights, pharmaceutical innovation, and economic competitiveness got little media representation. Civil society dominated the media contents, followed far behind by the Canadian government, the research-based and generic pharmaceutical industries. Developing country representatives were hardly represented in the media. Conclusions Media framing obscured the discussion of some of the underlying policy goals in this case and failed to highlight issues which are now significant barriers to the use of the

  13. Framing access to medicines in developing countries: an analysis of media coverage of Canada's Access to Medicines Regime.

    Science.gov (United States)

    Esmail, Laura C; Phillips, Kaye; Kuek, Victoria; Cosio, Andrea Perez; Kohler, Jillian Clare

    2010-01-04

    In September 2003, the Canadian government committed to developing legislation that would facilitate greater access to affordable medicines for developing countries. Over the course of eight months, the legislation, now known as Canada's Access to Medicines Regime (CAMR), went through a controversial policy development process and the newspaper media was one of the major venues in which the policy debates took place. The purpose of this study was to examine how the media framed CAMR to determine how policy goals were conceptualized, which stakeholder interests controlled the public debate and how these variables related to the public policy process. We conducted a qualitative content analysis of newspaper coverage of the CAMR policy and implementation process from 2003-2008. The primary theoretical framework for this study was framing theory. A total of 90 articles from 11 Canadian newspapers were selected for inclusion in our analysis. A team of four researchers coded the articles for themes relating to access to medicines and which stakeholders' voice figured more prominently on each issue. Stakeholders examined included: the research-based industry, the generic industry, civil society, the Canadian government, and developing country representatives. The most frequently mentioned themes across all documents were the issues of drug affordability, intellectual property, trade agreements and obligations, and development. Issues such as human rights, pharmaceutical innovation, and economic competitiveness got little media representation. Civil society dominated the media contents, followed far behind by the Canadian government, the research-based and generic pharmaceutical industries. Developing country representatives were hardly represented in the media. Media framing obscured the discussion of some of the underlying policy goals in this case and failed to highlight issues which are now significant barriers to the use of the legislation. Using the media to engage

  14. Secure Processing Offload in Recombining Media Segments for Mobile Access

    NARCIS (Netherlands)

    Veugen, P.J.M.; Stokking, H.M.

    2013-01-01

    We develop an architecture for a federation of home gateways. We distinguish inner and outer circle friends and describe a mechanism for social-aware backup of content and sharing with friends. To facilitate remote access, content can be segmented and redundantly stored at gateways of friends. We

  15. Alternatives for Monitoring and Limiting Network Access to Students in Network-Connected Classrooms

    Science.gov (United States)

    Almeroth, Kevin; Zhang, Hangjin

    2013-01-01

    With the advent of laptop computers and network technology, many classrooms are now being equipped with Internet connections, either through wired connections or wireless infrastructure. Internet access provides students an additional source from which to obtain course-related information. However, constant access to the Internet can be a…

  16. Optimal Guaranteed Services Timed Token (OGSTT) Media Access ...

    African Journals Online (AJOL)

    In order to provide better support for both real-time traffic and non-real-time on the same local area network, OGSTT employs the timed-token mechanisms in the Timely-Token protocol along with that of Budget Sharing Token (BuST) protocol. Some bounds on the behavior of OGSTT protocol are discussed along with the ...

  17. Online Activities, Digital Media Literacy, and Networked Individualism of Korean Youth

    Science.gov (United States)

    Park, Sora; Kim, Eun-mee; Na, Eun-Yeong

    2015-01-01

    Networked individualism enables Internet users to connect and socialize via their loose and transient multiple networks, whereas digital media literacy is a precondition of effective Internet use. In this study, an attempt has been made to find the link between networked individualism, digital media literacy, and young people's perception of their…

  18. A Service Oriented Architecture for Personalized Universal Media Access

    Directory of Open Access Journals (Sweden)

    Ingo Brunkhorst

    2011-04-01

    Full Text Available Multimedia streaming means delivering continuous data to a plethora of client devices. Besides the actual data transport, this also needs a high degree of content adaptation respecting the end users’ needs given by content preferences, transcoding constraints, and device capabilities. Such adaptations can be performed in many ways, usually on the media server. However, when it comes to content editing, like mixing in subtitles or picture-in-picture composition, relying on third party service providers may be necessary. For economic reasons this should be done in a service-oriented way, because a lot of adaptation modules can be reused within different adaptation workflows. Although service-oriented architectures have become widely accepted in the Web community, the multimedia environment is still dominated by monolithic systems. The main reason is the insufficient support for working with continuous data: generally the suitability of Web services for handling complex data types and state-full applications is still limited. In this paper we discuss extensions of Web service frameworks, and present a first implementation of a service-oriented framework for media streaming and digital item adaptation. The focus lies on the technical realization of the services. Our experimental results show the practicality of the actual deployment of service-oriented multimedia frameworks.

  19. Sport, Media and Sponsor: the Shifting Balance of Power in the Sports Network

    OpenAIRE

    Wolfe, Rosita; Meenaghan, Tony; O?Sullivan, Paul

    1997-01-01

    As sport has become an important social and economic activity it is increasingly the subject of management analysis. This article adopts a network perspective to examine developments in the sports network. In particular, it examines relationships between network "actors" such as corporate sponsors, media and the owners of sport and analyses the changing balance of power in the sports network. Key media drivers of change in the network such as cable and satellite television, pay-per-view and d...

  20. Scalable and Media Aware Adaptive Video Streaming over Wireless Networks

    Science.gov (United States)

    Tizon, Nicolas; Pesquet-Popescu, Béatrice

    2008-12-01

    This paper proposes an advanced video streaming system based on scalable video coding in order to optimize resource utilization in wireless networks with retransmission mechanisms at radio protocol level. The key component of this system is a packet scheduling algorithm which operates on the different substreams of a main scalable video stream and which is implemented in a so-called media aware network element. The concerned type of transport channel is a dedicated channel subject to parameters (bitrate, loss rate) variations on the long run. Moreover, we propose a combined scalability approach in which common temporal and SNR scalability features can be used jointly with a partitioning of the image into regions of interest. Simulation results show that our approach provides substantial quality gain compared to classical packet transmission methods and they demonstrate how ROI coding combined with SNR scalability allows to improve again the visual quality.

  1. Evaluating Social Media Networks in Medicines Safety Surveillance: Two Case Studies.

    Science.gov (United States)

    Coloma, Preciosa M; Becker, Benedikt; Sturkenboom, Miriam C J M; van Mulligen, Erik M; Kors, Jan A

    2015-10-01

    There is growing interest in whether social media can capture patient-generated information relevant for medicines safety surveillance that cannot be found in traditional sources. The aim of this study was to evaluate the potential contribution of mining social media networks for medicines safety surveillance using the following associations as case studies: (1) rosiglitazone and cardiovascular events (i.e. stroke and myocardial infarction); and (2) human papilloma virus (HPV) vaccine and infertility. We collected publicly accessible, English-language posts on Facebook, Google+, and Twitter until September 2014. Data were queried for co-occurrence of keywords related to the drug/vaccine and event of interest within a post. Messages were analysed with respect to geographical distribution, context, linking to other web content, and author's assertion regarding the supposed association. A total of 2537 posts related to rosiglitazone/cardiovascular events and 2236 posts related to HPV vaccine/infertility were retrieved, with the majority of posts representing data from Twitter (98 and 85%, respectively) and originating from users in the US. Approximately 21% of rosiglitazone-related posts and 84% of HPV vaccine-related posts referenced other web pages, mostly news items, law firms' websites, or blogs. Assertion analysis predominantly showed affirmation of the association of rosiglitazone/cardiovascular events (72%; n = 1821) and of HPV vaccine/infertility (79%; n = 1758). Only ten posts described personal accounts of rosiglitazone/cardiovascular adverse event experiences, and nine posts described HPV vaccine problems related to infertility. Publicly available data from the considered social media networks were sparse and largely untrackable for the purpose of providing early clues of safety concerns regarding the prespecified case studies. Further research investigating other case studies and exploring other social media platforms are necessary to further characterise

  2. The Vulnerability of Social Networking Media and the Insider Threat: New Eyes for Bad Guys

    Science.gov (United States)

    2011-09-01

    34 Figure 2. Steps to Exploit Social Networking Media of Information-Gathering This social networking media and “ deep Web ” search9 information...networking media to discover that the CEO and junior manager having a strong 9 Deep web search engines...were not feasible for widespread use for a large organization’s employees. Two of the respondents, with firms that conduct deep Web searches and

  3. An Efficient Channel Access Scheme for Vehicular Ad Hoc Networks

    Directory of Open Access Journals (Sweden)

    Syed Asad Hussain

    2017-01-01

    Full Text Available Vehicular Ad Hoc Networks (VANETs are getting more popularity due to the potential Intelligent Transport Systems (ITS technology. It provides many efficient network services such as safety warnings (collision warning, entertainment (video and voice, maps based guidance, and emergency information. VANETs most commonly use Road Side Units (RSUs and Vehicle-to-Vehicle (V2V referred to as Vehicle-to-Infrastructure (V2I mode for data accessing. IEEE 802.11p standard which was originally designed for Wireless Local Area Networks (WLANs is modified to address such type of communication. However, IEEE 802.11p uses Distributed Coordination Function (DCF for communication between wireless nodes. Therefore, it does not perform well for high mobility networks such as VANETs. Moreover, in RSU mode timely provision of data/services under high density of vehicles is challenging. In this paper, we propose a RSU-based efficient channel access scheme for VANETs under high traffic and mobility. In the proposed scheme, the contention window is dynamically varied according to the times (deadlines the vehicles are going to leave the RSU range. The vehicles with shorter time deadlines are served first and vice versa. Simulation is performed by using the Network Simulator (NS-3 v. 3.6. The simulation results show that the proposed scheme performs better in terms of throughput, backoff rate, RSU response time, and fairness.

  4. Preferred access in packet-switching radio networks

    Science.gov (United States)

    Shacham, N.

    Channel-access protocols that provide prioritized access to a common channel in a packet switching network are considered. The elements of such protocols are discussed and a specific protocol that integrates two types of packets is proposed. A probabilistic model of the protocol is presented, and its analysis yields the throughput-delay characteristics of the two classes and the interaction between them. The model is analyzed by a method similar to the one used in priority queues; this method allows consideration of each class separately, thus reducing the computational effort substantially.

  5. A Fuzzy Preprocessing Module for Optimizing the Access Network Selection in Wireless Networks

    Directory of Open Access Journals (Sweden)

    Faisal Kaleem

    2013-01-01

    Full Text Available A heterogeneous wireless network is characterized by the presence of different wireless access technologies that coexist in an overlay fashion. These wireless access technologies usually differ in terms of their operating parameters. On the other hand, Mobile Stations (MSs in a heterogeneous wireless network are equipped with multiple interfaces to access different types of services from these wireless access technologies. The ultimate goal of these heterogeneous wireless networks is to provide global connectivity with efficient ubiquitous computing to these MSs based on the Always Best Connected (ABC principle. This is where the need for intelligent and efficient Vertical Handoffs (VHOs between wireless technologies in a heterogeneous environment becomes apparent. This paper presents the design and implementation of a fuzzy multicriteria based Vertical Handoff Necessity Estimation (VHONE scheme that determines the proper time for VHO, while considering the continuity and quality of the currently utilized service, and the end-users' satisfaction.

  6. Empathic Cyberactivism: The Potential of Hyperconnected Social Media Networks and Empathic Virtual Reality for Feminism

    Directory of Open Access Journals (Sweden)

    Penelope Kemekenidou

    2016-10-01

    Full Text Available The rise of misogyny on social networks feels both devastating and endless. Whether one believes that misogyny has risen to a new level, or that it has simply become more visible through the internet, one thing is clear: with the ubiquity and accessibility of ‘immortal’ online information, harassment and discrimination, shared via hyperconnected social media networks, can be taken to a new, much more visible level. Hyperconnectivity enables sexism to multiply on the web – but it can also be the solution to fight it. In the context of activism, hyperconnectivity can be a major force to combat inequality—given that this hyperconnectivity is linked to empathy and not aggression. If this is the case, I argue, new technologies, for example virtual reality, open up new spaces of empathetic interaction.

  7. A spontaneous ad hoc network to share www access

    OpenAIRE

    Lloret Jaime; Garcia Miguel; Peñalver Lourdes; Lacuesta Raquel

    2010-01-01

    In this paper, we propose a secure spontaneous ad-hoc network, based on direct peer-to-peer interaction, to grant a quick, easy, and secure access to the users to surf the Web. The paper shows the description of our proposal, the procedure of the nodes involved in the system, the security algorithms implemented, and the designed messages. We have taken into account the security and its performance. Although some people have defined and described the main features of spontaneous ad-hoc network...

  8. Fiber-Wireless (FiWi Broadband Access Networks in an Age of Convergence: Past, Present, and Future

    Directory of Open Access Journals (Sweden)

    Martin Maier

    2014-01-01

    Full Text Available After describing the beginnings and state of the art of integrated fiber-wireless (FiWi broadband access networks in great detail, we briefly review recent progress and point to various ongoing research activities, including the design of energy-efficient “green” FiWi access networks, advanced survivability techniques, and integration of wireless and fiber optic sensors, towards realizing adaptable, dependable, and ecoconscious future-proof broadband access networks based on both wireless and shared passive fiber media. Furthermore, we discuss service, application, business, and operation related aspects, which motivate access technology to move into a substantially different direction in the long run than continued capacity provisioning. Given that most 4G cellular mobile network researches so far have been focusing on the achievable performance gains in the wireless front-end only without looking into the details of backhaul implementations and possible backhaul bottlenecks, we identify open key research challenges for FiWi broadband access networks. We explore ways of how they can be deployed across relevant economic sectors other than telecommunications per se, taking major paradigm shifts such as the Third Industrial Revolution, Energy Internet, smart grid, and explosion of mobile data traffic in today’s cellular networks into account.

  9. Social Network, Surgeon, and Media Influence on the Decision to Undergo Contralateral Prophylactic Mastectomy.

    Science.gov (United States)

    Venetis, Maria K; MacGeorge, Erina L; Baptiste, Dadrie F; Mouton, Ashton; Friley, Lorin B; Pastor, Rebekah; Hatten, Kristen; Lagoo, Janaka; Bowling, Monet W; Clare, Susan E

    2016-07-26

    The rate of contralateral prophylactic mastectomy (CPM) has risen sharply in the past decade. The current study was designed to examine social network, surgeon, and media influence on patients' CPM decision-making, examining not only who influenced the decision, and to what extent, but also the type of influence exerted. Patients (N=113) who underwent CPM at 4 Indiana University-affiliated hospitals between 2008 and 2012 completed structured telephone interviews in 2013. Questions addressed the involvement and influence of the social network (family, friends, and nonsurgeon health professionals), surgeon, and media on the CPM decision. Spouses, children, family, friends, and health professionals were reported as exerting a meaningful degree of influence on patients' decisions, largely in ways that were positive or neutral toward CPM. Most surgeons were regarded as providing options rather than encouraging or discouraging CPM. Media influence was present, but limited. Patients who choose CPM do so with influence and support from members of their social networks. Reversing the increasing choice of CPM will require educating these influential others, which can be accomplished by encouraging patients to include them in clinical consultations, and by providing patients with educational materials that can be shared with their social networks. Surgeons need to be perceived as having an opinion, specifically that CPM should be reserved for those patients for whom it is medically indicated.This is an open-access article distributed under the terms of the Creative Commons Attribution-Non Commercial-No Derivatives License 4.0 (CCBY-NC-ND), where it is permissible to download and share the work provided it is properly cited. The work cannot be changed in any way or used commercially. http://creativecommons.org/licenses/by-nc-nd/4.0/.

  10. Adaptive Information Access on Multiple Applications Support Wireless Sensor Networks

    DEFF Research Database (Denmark)

    Tobgay, Sonam; Olsen, Rasmus Løvenstein; Prasad, Ramjee

    2014-01-01

    is used for safety and security monitoring purposes. In this paper, we evaluate different access strategies to remote dynamic information and compare between achieving information reliability (mismatch probability) and the associated power consumption. Lastly, based on the models, we propose an adaptive......Accessing information remotely to dynamically changing information elements cannot be avoided and has become a required functionality for various network services. Most applications require up-to-date information which is reliable and accurate. The information reliability in terms of using correct...... information is challenged by dynamic nature of information elements. These challenges are more prominent in case of wireless sensor network (WSN) applications, as the information that the sensor node collects are mostly dynamic in nature (say, temperature). Therefore, it is likely that there can be a mismatch...

  11. A Network Access Control Framework for 6LoWPAN Networks

    Science.gov (United States)

    Oliveira, Luís M. L.; Rodrigues, Joel J. P. C.; de Sousa, Amaro F.; Lloret, Jaime

    2013-01-01

    Low power over wireless personal area networks (LoWPAN), in particular wireless sensor networks, represent an emerging technology with high potential to be employed in critical situations like security surveillance, battlefields, smart-grids, and in e-health applications. The support of security services in LoWPAN is considered a challenge. First, this type of networks is usually deployed in unattended environments, making them vulnerable to security attacks. Second, the constraints inherent to LoWPAN, such as scarce resources and limited battery capacity, impose a careful planning on how and where the security services should be deployed. Besides protecting the network from some well-known threats, it is important that security mechanisms be able to withstand attacks that have not been identified before. One way of reaching this goal is to control, at the network access level, which nodes can be attached to the network and to enforce their security compliance. This paper presents a network access security framework that can be used to control the nodes that have access to the network, based on administrative approval, and to enforce security compliance to the authorized nodes. PMID:23334610

  12. Predicting Social Networking Site Use and Online Communication Practices among Adolescents: The Role of Access and Device Ownership

    Directory of Open Access Journals (Sweden)

    Drew P. Cingel

    2014-06-01

    Full Text Available Given adolescents' heavy social media use, this study examined a number of predictors of adolescent social media use, as well as predictors of online communication practices. Using data collected from a national sample of 467 adolescents between the ages of 13 and 17, results indicate that demographics, technology access, and technology ownership are related to social media use and communication practices. Specifically, females log onto and use more constructive com-munication practices on Facebook compared to males. Additionally, adolescents who own smartphones engage in more constructive online communication practices than those who share regular cell phones or those who do not have access to a cell phone. Overall, results imply that ownership of mobile technologies, such as smartphones and iPads, may be more predictive of social networking site use and online communication practices than general ownership of technology.

  13. Predicting Social Networking Site Use and Online Communication Practices among Adolescents: The Role of Access and Device Ownership

    Directory of Open Access Journals (Sweden)

    Drew P. Cingel

    2014-01-01

    Full Text Available Given adolescents' heavy social media use, this study examined a number of predictors of adolescent social media use, as well as predictors of online communication practices. Using data collected from a national sample of 467 adolescents between the ages of 13 and 17, results indicate that demographics, technology access, and technology ownership are related to social media use and communication practices. Specifically, females log onto and use more constructive communication practices on Facebook compared to males. Additionally, adolescents who own smartphones engage in more constructive online communication practices than those who share regular cell phones or those who do not have access to a cell phone. Overall, results imply that ownership of mobile technologies, such as smartphones and iPads, may be more predictive of social networking site use and online communication practices than general ownership of technology.

  14. Network Performance and Quality of Experience of Remote Access Laboratories

    Directory of Open Access Journals (Sweden)

    Alexander A. Kist

    2012-11-01

    Full Text Available Remote Access Laboratories (RAL have become important learning and teaching tools. This paper presents a performance study that targets a specific remote access architecture implemented within a universities operational environment. This particular RAL system provides globally authenticated and arbitrated remote access to virtualized computers as well as computer controlled hardware experiments. This paper presents system performance results that have been obtained utilizing both a set of automated and human subject tests. Principle objectives of the study were: To gain a better understanding of the nature of network traffic caused by experimental activity usage; to obtain an indication of user expectations of activity performance; and to develop a measure to predict Quality of Experience, based on easily measurable Quality of Service parameters. The study emulates network layer variation of access-bandwidth and round-trip-time of typical usage scenarios and contrasts against user perception results that allow classifying expected user performance. It demonstrates that failure rate is excellent measure of usability, and that round-trip-time predominantly affects user experience. Thin-client and remote desktop architectures are popular to separate the location of users and the actual data processing and use similar structures, hence results of this study to be applied in these application areas as well.

  15. Monday 9 January 2006: RESTRICTED ACCESS to the Technical Network

    CERN Multimedia

    CNIC Users Exchange and IT/CS

    2005-01-01

    As of Monday 9 January 2006, Ethernet access from the general CERN network to the Technical Network (TN) will be restricted in order to improve security on the TN. As a result, all Ethernet communication between the General Purpose Network (GPN) and the TN will be filtered. Only communication lines to the general IT services such as DNS, TP, NICE, DFS, AFS, Antivirus, Linux installation servers, License servers, OracleDB, TSM backup servers and dedicated AB and TS servers on the GPN will remain open. Please make sure that all your devices are registered properly in the network database (LANDB): http://network.cern.ch/. You are encouraged to make proper use of the 'Tag' and 'Description' fields in order to identify your system later on. If your system depends on special services on the GPN or is split between the GPN and the TN, e.g. consists of devices (PCs, PLCs, VME crates, webcams, etc.) connected to both the TN and the GPN, please contact the Technical-Network.Administrator@cern.ch . They will include...

  16. Distributed cloud association in downlink multicloud radio access networks

    KAUST Repository

    Dahrouj, Hayssam

    2015-03-01

    This paper considers a multicloud radio access network (M-CRAN), wherein each cloud serves a cluster of base-stations (BS\\'s) which are connected to the clouds through high capacity digital links. The network comprises several remote users, where each user can be connected to one (and only one) cloud. This paper studies the user-to-cloud-assignment problem by maximizing a network-wide utility subject to practical cloud connectivity constraints. The paper solves the problem by using an auction-based iterative algorithm, which can be implemented in a distributed fashion through a reasonable exchange of information between the clouds. The paper further proposes a centralized heuristic algorithm, with low computational complexity. Simulations results show that the proposed algorithms provide appreciable performance improvements as compared to the conventional cloud-less assignment solutions. © 2015 IEEE.

  17. Participation and Autonomy for Users with ABI Through Easy Social Media Access.

    Science.gov (United States)

    Dirks, Susanne; Bühler, Christian

    2017-01-01

    The Mediata app is a mobile application providing easy access to internet and social media for persons with acquired brain injury. This paper presents design, working hypotheses and expected results of a participative user experience study to evaluate the impact of the Mediata application on participation and autonomy of users with acquired brain injury.

  18. Preference for and access to media resources as predictors of in ...

    African Journals Online (AJOL)

    The study investigated the extent to which preference for and access to media resources predicts knowledge of in-school adolescents to sexual and reproductive health issues in Lagos Mainland Local Government Area of Lagos State, Nigeria. A population of 526 in-school adolescents participates in the study while ...

  19. Joint Hybrid Backhaul and Access Links Design in Cloud-Radio Access Networks

    KAUST Repository

    Dhifallah, Oussama Najeeb

    2015-09-06

    The cloud-radio access network (CRAN) is expected to be the core network architecture for next generation mobile radio systems. In this paper, we consider the downlink of a CRAN formed of one central processor (the cloud) and several base station (BS), where each BS is connected to the cloud via either a wireless or capacity-limited wireline backhaul link. The paper addresses the joint design of the hybrid backhaul links (i.e., designing the wireline and wireless backhaul connections from the cloud to the BSs) and the access links (i.e., determining the sparse beamforming solution from the BSs to the users). The paper formulates the hybrid backhaul and access link design problem by minimizing the total network power consumption. The paper solves the problem using a two-stage heuristic algorithm. At one stage, the sparse beamforming solution is found using a weighted mixed 11/12 norm minimization approach; the correlation matrix of the quantization noise of the wireline backhaul links is computed using the classical rate-distortion theory. At the second stage, the transmit powers of the wireless backhaul links are found by solving a power minimization problem subject to quality-of-service constraints, based on the principle of conservation of rate by utilizing the rates found in the first stage. Simulation results suggest that the performance of the proposed algorithm approaches the global optimum solution, especially at high signal-to-interference-plus-noise ratio (SINR).

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

    Directory of Open Access Journals (Sweden)

    Misun Ahn

    2017-12-01

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

  1. A Fine-Grained Data Access Control System in Wireless Sensor Network

    National Research Council Canada - National Science Library

    Boniface K. Alese; Sylvester O. Olatunji; Oluwatoyin C. Agbonifo; Aderonke F. Thompson

    2015-01-01

    .... Consequently, data insecurity becomes a big concern. This study, therefore, proposes a fine-grained access control system which only requires the right set of users to access a particular data, based on their access privileges in the sensor networks...

  2. Supporting Dynamic Spectrum Access in Heterogeneous LTE+ Networks

    Energy Technology Data Exchange (ETDEWEB)

    Luiz A. DaSilva; Ryan E. Irwin; Mike Benonis

    2012-08-01

    As early as 2014, mobile network operators’ spectral capac- ity is expected to be overwhelmed by the demand brought on by new devices and applications. With Long Term Evo- lution Advanced (LTE+) networks likely as the future one world 4G standard, network operators may need to deploy a Dynamic Spectrum Access (DSA) overlay in Heterogeneous Networks (HetNets) to extend coverage, increase spectrum efficiency, and increase the capacity of these networks. In this paper, we propose three new management frameworks for DSA in an LTE+ HetNet: Spectrum Accountability Client, Cell Spectrum Management, and Domain Spectrum Man- agement. For these spectrum management frameworks, we define protocol interfaces and operational signaling scenar- ios to support cooperative sensing, spectrum lease manage- ment, and alarm scenarios for rule adjustment. We also quan- tify, through integer programs, the benefits of using DSA in an LTE+ HetNet, that can opportunistically reuse vacant TV and GSM spectrum. Using integer programs, we consider a topology using Geographic Information System data from the Blacksburg, VA metro area to assess the realistic benefits of DSA in an LTE+ HetNet.

  3. Performance of SON for RSRP-based LTE/WLAN access network selection

    NARCIS (Netherlands)

    Kovács, I.Z.; Laselva, D.; Michaelsen, P.H.; Wang, Y.; Djapic, R.; Spaey, K.

    2014-01-01

    Carrier-grade Wireless Local Area Network (WLAN) is becoming an important complementary system to cellular networks for Mobile Network Operators (MNOs). Network controlled access network selection between cellular and WLAN is an essential functionality to optimize network performance and user

  4. Extending AAA operational model for profile-based access control in ethernet-based Neutral Access Networks

    NARCIS (Netherlands)

    Matias, J.; Jacob, E.; Demchenko, Y.; de Laat, C.; Gommans, L.; Macías López, E.M.; Bogliolo, A.; Perry, M.; Ran, M

    2010-01-01

    Neutral Access Networks (NAN) have appeared as a new model to overcome some restrictions and lack of flexibility that are present currently in broadband access networks. NAN brings new business opportunities by opening this market to new stakeholders. Although the NAN model is accepted, there are

  5. Professional Online Presence and Learning Networks: Educating for Ethical Use of Social Media

    Science.gov (United States)

    Forbes, Dianne

    2017-01-01

    In a teacher education context, this study considers the use of social media for building a professional online presence and learning network. This article provides an overview of uses of social media in teacher education, presents a case study of key processes in relation to professional online presence and learning networks, and highlights…

  6. 77 FR 36305 - Stream Communications Network & Media, Inc.; Order of Suspension of Trading

    Science.gov (United States)

    2012-06-18

    ... From the Federal Register Online via the Government Publishing Office SECURITIES AND EXCHANGE COMMISSION Stream Communications Network & Media, Inc.; Order of Suspension of Trading June 14, 2012. It... concerning the securities of Stream Communications Network & Media, Inc. because it has not filed any...

  7. How Many "Friends" Do You Need? Teaching Students How to Network Using Social Media

    Science.gov (United States)

    Sacks, Michael Alan; Graves, Nikki

    2012-01-01

    Student reliance on social media is undeniable. However, while we largely regard social media as a new phenomena, the concepts underlying it come directly from social network theory in sociology and organizational behavior. In this article, the authors examine how the social network concepts of size, quality, complexity, diffusion, and distance…

  8. Navigating Social Networking and Social Media in School Psychology: Ethical and Professional Considerations in Training Programs

    Science.gov (United States)

    Pham, Andy V.

    2014-01-01

    Social networking and social media have undoubtedly proliferated within the past decade, allowing widespread communication and dissemination of user-generated content and information. Some psychology graduate programs, including school psychology, have started to embrace social networking and media for instructional and training purposes; however,…

  9. Research on Acceptance Effect of Ideological and Political Education among College Students Based on Network Media

    National Research Council Canada - National Science Library

    Jia Li; Huichuan Zhang; Xinli Lu

    2016-01-01

    ... the realistic significance of research on acceptance effect of ideological and political education among college students based on network media by starting from analyzing the practical problems and through checking literature material from summarizing the meaning, features and current development situation of network media. At the same time, ...

  10. Accessing Wireless Sensor Networks Via Dynamically Reconfigurable Interaction Models

    Directory of Open Access Journals (Sweden)

    Maria Cecília Gomes

    2012-12-01

    Full Text Available The Wireless Sensor Networks (WSNs technology is already perceived as fundamental for science across many domains, since it provides a low cost solution for environment monitoring. WSNs representation via the service concept and its inclusion in Web environments, e.g. through Web services, supports particularly their open/standard access and integration. Although such Web enabled WSNs simplify data access, network parameterization and aggregation, the existing interaction models and run-time adaptation mechanisms available to clients are still scarce. Nevertheless, applications increasingly demand richer and more flexible accesses besides the traditional client/server. For instance, applications may require a streaming model in order to avoid sequential data requests, or the asynchronous notification of subscribed data through the publish/subscriber. Moreover, the possibility to automatically switch between such models at runtime allows applications to define flexible context-based data acquisition. To this extent, this paper discusses the relevance of the session and pattern abstractions on the design of a middleware prototype providing richer and dynamically reconfigurable interaction models to Web enabled WSNs.

  11. Non-Orthogonal Multiple Access for Ubiquitous Wireless Sensor Networks.

    Science.gov (United States)

    Anwar, Asim; Seet, Boon-Chong; Ding, Zhiguo

    2018-02-08

    Ubiquitous wireless sensor networks (UWSNs) have become a critical technology for enabling smart cities and other ubiquitous monitoring applications. Their deployment, however, can be seriously hampered by the spectrum available to the sheer number of sensors for communication. To support the communication needs of UWSNs without requiring more spectrum resources, the power-domain non-orthogonal multiple access (NOMA) technique originally proposed for 5th Generation (5G) cellular networks is investigated for UWSNs for the first time in this paper. However, unlike 5G networks that operate in the licensed spectrum, UWSNs mostly operate in unlicensed spectrum where sensors also experience cross-technology interferences from other devices sharing the same spectrum. In this paper, we model the interferences from various sources at the sensors using stochastic geometry framework. To evaluate the performance, we derive a theorem and present new closed form expression for the outage probability of the sensors in a downlink scenario under interference limited environment. In addition, diversity analysis for the ordered NOMA users is performed. Based on the derived outage probability, we evaluate the average link throughput and energy consumption efficiency of NOMA against conventional orthogonal multiple access (OMA) technique in UWSNs. Further, the required computational complexity for the NOMA users is presented.

  12. Amplified CWDM-based Next Generation Broadband Access Networks

    Science.gov (United States)

    Peiris, Sasanthi Chamarika

    The explosive growth of both fixed and mobile data-centric traffic along with the inevitable trend towards all-IP/Ethernet transport protocols and packet switched networks will ultimately lead to an all-packet-based converged fixed-mobile optical transport network from the core all the way out to the access network. To address the increasing capacity and speed requirements in the access networks, Wavelength-Division Multiplexed (WDM) and/or Coarse WDM (CWDM)-based Passive Optical Networks (PONs) are expected to emerge as the next-generation optical access infrastructures. However, due to several techno-economic hurdles, CWDM-PONs are still considered an expensive solution and have not yet made any significant inroads into the current access area. One of the key technology hurdles is the scalability of the CWDM-based PONs. Passive component optical insertion losses limit the reach of the network or the number of served optical network units (ONUs). In the recent years, optical amplified CWDM approaches have emerged and new designs of optical amplifiers have been proposed and demonstrated. The critical design parameter for these amplifiers is the very wide optical amplification bandwidth (e.g., 340 nm combined for both directions). The objective of this PhD dissertation work is first to engineer ring and tree-ring based PON architectures that can achieve longer unamplified PON reach and/or provide service to a greater number of ONUs and customers. Secondly is to develop new novel optical amplifier schemes to further address the scalability limitation of the CWDM-based PONs. Specifically, this work proposes and develops novel ultra wide-band hybrid Raman-Optical parametric amplifier (HROPA) schemes that operate over nearly the entire specified CWDM band to provide 340 nm bidirectional optical gain bandwidth over the amplified PON's downstream and upstream CWDM wavelength bands (about 170 nm in each direction). The performance of the proposed HROPA schemes is assessed

  13. Symmetric reconfigurable capacity assignment in a bidirectional DWDM access network.

    Science.gov (United States)

    Ortega, Beatriz; Mora, José; Puerto, Gustavo; Capmany, José

    2007-12-10

    This paper presents a novel architecture for DWDM bidirectional access networks providing symmetric dynamic capacity allocation for both downlink and uplink signals. A foldback arrayed waveguide grating incorporating an optical switch enables the experimental demonstration of flexible assignment of multiservice capacity. Different analog and digital services, such as CATV, 10 GHz-tone, 155Mb/s PRBS and UMTS signals have been transmitted in order to successfully test the system performance under different scenarios of total capacity distribution from the Central Station to different Base Stations with two reconfigurable extra channels for each down and upstream direction.

  14. Journalists' Perceptions of Nomenklatura Networks and Media Ownership in Post-communist Bulgaria

    Directory of Open Access Journals (Sweden)

    Lada Trifonova Price

    2015-06-01

    Full Text Available This article discusses the role of the former communist party elite (the nomenklatura in the Bulgarian post-communist media landscape in relation to media ownership and the origin of media outlets’ capital. The spotlight is on Bulgarian journalists’ perceptions explored in semi-structured interviews with media professionals from the capital city, Sofia. The findings indicate that Bulgarian journalists are strongly interested in, and concerned with, the influence of members of the former nomenklatura and their informal networks on the Bulgarian media landscape and particularly on the way Bulgarian media in Bulgaria have been owned and financed since 1989.

  15. A Spontaneous Ad Hoc Network to Share WWW Access

    Directory of Open Access Journals (Sweden)

    Raquel Lacuesta

    2010-01-01

    Full Text Available In this paper, we propose a secure spontaneous ad-hoc network, based on direct peer-to-peer interaction, to grant a quick, easy, and secure access to the users to surf the Web. The paper shows the description of our proposal, the procedure of the nodes involved in the system, the security algorithms implemented, and the designed messages. We have taken into account the security and its performance. Although some people have defined and described the main features of spontaneous ad-hoc networks, nobody has published any design and simulation until today. Spontaneous networking will enable a more natural form of wireless computing when people physically meet in the real world. We also validate the success of our proposal through several simulations and comparisons with a regular architecture, taking into account the optimization of the resources of the devices. Finally, we compare our proposal with other caching techniques published in the related literature. The proposal has been developed with the main objective of improving the communication and integration between different study centers of low-resource communities. That is, it lets communicate spontaneous networks, which are working collaboratively and which have been created on different physical places.

  16. More Voices Than Ever? Quantifying Media Bias in Networks

    OpenAIRE

    Lin, Yu-Ru; Bagrow, James P.; Lazer, David

    2011-01-01

    Social media, such as blogs, are often seen as democratic entities that allow more voices to be heard than the conventional mass or elite media. Some also feel that social media exhibits a balancing force against the arguably slanted elite media. A systematic comparison between social and mainstream media is necessary but challenging due to the scale and dynamic nature of modern communication. Here we propose empirical measures to quantify the extent and dynamics of social (blog) and mainstre...

  17. Social media and professional networking: a case of information professionals in the SCECSAL region

    OpenAIRE

    Chisenga, Justin; Chande-Mallya, Rehema

    2012-01-01

    The purpose of the study was to establish the extent to which library and information professionals in the Standing Conference of Eastern, Central and Southern Africa Library and Information Associations (SCECSAL) region are using social media applications for professional networking. The findings show that although the professionals are adopting social media applications, its use is more for social networking than professional networking purposes. Among those using the applications for profe...

  18. Misoprostol: percursos, mediações e redes sociais para o acesso ao aborto medicamentoso em contextos de ilegalidade no Estado de São Paulo Misoprostol: pathways, mediation and social networks for access to abortion using medication in the context of illegality in the State of Sao Paulo

    Directory of Open Access Journals (Sweden)

    Margareth Martha Arilha

    2012-07-01

    are illegally traded in Brazil, in different ways and in different contexts. As a result, women are exposed to different degrees of vulnerability depending directly on the steps taken, types of mediation used and social networks they belong to. These are the ways in which women and men obtain access to the use of misoprostol for abortion, the outcome of which may be successful or not.

  19. Design, Implementation and Optimization of Innovative Internet Access Networks, based on Fog Computing and Software Defined Networking

    OpenAIRE

    Iotti, Nicola

    2017-01-01

    1. DESIGN In this dissertation we introduce a new approach to Internet access networks in public spaces, such as Wi-Fi network commonly known as Hotspot, based on Fog Computing (or Edge Computing), Software Defined Networking (SDN) and the deployment of Virtual Machines (VM) and Linux containers, on the edge of the network. In this vision we deploy specialized network elements, called Fog Nodes, on the edge of the network, able to virtualize the physical infrastructure and expose APIs to e...

  20. Enhancing Sensing and Channel Access in Cognitive Radio Networks

    KAUST Repository

    Hamza, Doha R.

    2014-06-18

    Cognitive radio technology is a promising technology to solve the wireless spectrum scarcity problem by intelligently allowing secondary, or unlicensed, users access to the primary, licensed, users\\' frequency bands. Cognitive technology involves two main tasks: 1) sensing the wireless medium to assess the presence of the primary users and 2) designing secondary spectrum access techniques that maximize the secondary users\\' benefits while maintaining the primary users\\' privileged status. On the spectrum sensing side, we make two contributions. First, we maximize a utility function representing the secondary throughput while constraining the collision probability with the primary below a certain value. We optimize therein the channel sensing time, the sensing decision threshold, the channel probing time, together with the channel sensing order for wideband primary channels. Second, we design a cooperative spectrum sensing technique termed sensing with equal gain combining whereby cognitive radios simultaneously transmit their sensing results to the fusion center over multipath fading reporting channels. The proposed scheme is shown to outperform orthogonal reporting systems in terms of achievable secondary throughput and to be robust against phase and synchronization errors. On the spectrum access side, we make four contributions. First, we design a secondary scheduling scheme with the goal of minimizing the secondary queueing delay under constraints on the average secondary transmit power and the maximum tolerable primary outage probability. Second, we design another secondary scheduling scheme based on the spectrum sensing results and the primary automatic repeat request feedback. The optimal medium access probabilities are obtained via maximizing the secondary throughput subject to constraints that guarantee quality of service parameters for the primary. Third, we propose a three-message superposition coding scheme to maximize the secondary throughput without

  1. Design of a of a survivable multi-wavelength photonic access network

    NARCIS (Netherlands)

    Roy, R.; van Etten, Wim

    2007-01-01

    This paper investigates the design of protection schemes in an extended access network. The network is modeled as a stack of quasi independent logical passive optical networks(PONs), each operating the IEEE Ethernet passive optical networks (EPON) protocol. The dynamics of the network operation when

  2. SON for LTE-WLAN access network selection : design and performance

    NARCIS (Netherlands)

    Willemen, P.; Laselva, D.; Wang, Y.; Kovács, I.; Djapic, R.; Moerman, I.

    2016-01-01

    Mobile network operators (MNOs) are deploying carrier-grade Wireless Local Area Network (WLAN) as an important complementary system to cellular networks. Access network selection (ANS) between cellular and WLAN is an essential component to improve network performance and user quality-of-service

  3. Social Media as Seismic Networks for the Earthquake Damage Assessment

    Science.gov (United States)

    Meletti, C.; Cresci, S.; La Polla, M. N.; Marchetti, A.; Tesconi, M.

    2014-12-01

    The growing popularity of online platforms, based on user-generated content, is gradually creating a digital world that mirrors the physical world. In the paradigm of crowdsensing, the crowd becomes a distributed network of sensors that allows us to understand real life events at a quasi-real-time rate. The SoS-Social Sensing project [http://socialsensing.it/] exploits the opportunistic crowdsensing, involving users in the sensing process in a minimal way, for social media emergency management purposes in order to obtain a very fast, but still reliable, detection of emergency dimension to face. First of all we designed and implemented a decision support system for the detection and the damage assessment of earthquakes. Our system exploits the messages shared in real-time on Twitter. In the detection phase, data mining and natural language processing techniques are firstly adopted to select meaningful and comprehensive sets of tweets. Then we applied a burst detection algorithm in order to promptly identify outbreaking seismic events. Using georeferenced tweets and reported locality names, a rough epicentral determination is also possible. The results, compared to Italian INGV official reports, show that the system is able to detect, within seconds, events of a magnitude in the region of 3.5 with a precision of 75% and a recall of 81,82%. We then focused our attention on damage assessment phase. We investigated the possibility to exploit social media data to estimate earthquake intensity. We designed a set of predictive linear models and evaluated their ability to map the intensity of worldwide earthquakes. The models build on a dataset of almost 5 million tweets exploited to compute our earthquake features, and more than 7,000 globally distributed earthquakes data, acquired in a semi-automatic way from USGS, serving as ground truth. We extracted 45 distinct features falling into four categories: profile, tweet, time and linguistic. We run diagnostic tests and

  4. Examining the use of evidence-based and social media supported tools in freely accessible physical activity intervention websites.

    Science.gov (United States)

    Vandelanotte, Corneel; Kirwan, Morwenna; Rebar, Amanda; Alley, Stephanie; Short, Camille; Fallon, Luke; Buzza, Gavin; Schoeppe, Stephanie; Maher, Carol; Duncan, Mitch J

    2014-08-17

    It has been shown that physical activity is more likely to increase if web-based interventions apply evidence-based components (e.g. self-monitoring) and incorporate interactive social media applications (e.g. social networking), but it is unclear to what extent these are being utilized in the publicly available web-based physical activity interventions. The purpose of this study was to evaluate whether freely accessible websites delivering physical activity interventions use evidence-based behavior change techniques and provide social media applications. In 2013, a systematic search strategy examined 750 websites. Data was extracted on a wide range of variables (e.g. self-monitoring, goal setting, and social media applications). To evaluate website quality a new tool, comprising three sub-scores (Behavioral Components, Interactivity and User Generated Content), was developed to assess implementation of behavior change techniques and social media applications. An overall website quality scored was obtained by summing the three sub-scores. Forty-six publicly available websites were included in the study. The use of self-monitoring (54.3%), goal setting (41.3%) and provision of feedback (46%) was relatively low given the amount of evidence supporting these features. Whereas the presence of features allowing users to generate content (73.9%), and social media components (Facebook (65.2%), Twitter (47.8%), YouTube (48.7%), smartphone applications (34.8%)) was relatively high considering their innovative and untested nature. Nearly all websites applied some behavioral and social media applications. The average Behavioral Components score was 3.45 (±2.53) out of 10. The average Interactivity score was 3.57 (±2.16) out of 10. The average User Generated Content Score was 4.02 (±2.77) out of 10. The average overall website quality score was 11.04 (±6.92) out of 30. Four websites (8.7%) were classified as high quality, 12 websites (26.1%) were classified as moderate

  5. Random access procedures and radio access network (RAN) overload control in standard and advanced long-term evolution (LTE and LTE-A) networks

    DEFF Research Database (Denmark)

    Kiilerich Pratas, Nuno; Thomsen, Henning; Popovski, Petar

    2015-01-01

    In this chapter, we describe and discuss the current LTE random access procedure and the Radio Access Network Load Control solution within LTE/LTE-A. We provide an overview of the several considered load control solutions and give a detailed description of the standardized Extended Access Class B...

  6. Software Defined Networking for Next Generation Converged Metro-Access Networks

    Science.gov (United States)

    Ruffini, M.; Slyne, F.; Bluemm, C.; Kitsuwan, N.; McGettrick, S.

    2015-12-01

    While the concept of Software Defined Networking (SDN) has seen a rapid deployment within the data center community, its adoption in telecommunications network has progressed slowly, although the concept has been swiftly adopted by all major telecoms vendors. This paper presents a control plane architecture for SDN-driven converged metro-access networks, developed through the DISCUS European FP7 project. The SDN-based controller architecture was developed in a testbed implementation targeting two main scenarios: fast feeder fiber protection over dual-homed Passive Optical Networks (PONs) and dynamic service provisioning over a multi-wavelength PON. Implementation details and results of the experiment carried out over the second scenario are reported in the paper, showing the potential of SDN in providing assured on-demand services to end-users.

  7. The Social Network: Keeping in Touch with Alumni through Online Media

    Science.gov (United States)

    Bunker, Matt

    2011-01-01

    Not all social-networking tools are created equal. Knowing where alumni are and what they're doing online is key when deciding what social networks to use. Knowing how to address and employ social networking can change the way institutions engage alumni. Social media help institutions connect with alumni; these tools help build, sustain, and even…

  8. Social Networking Media: An Approach for the Teaching of International Business

    Science.gov (United States)

    Barczyk, Casimir C.; Duncan, Doris G.

    2012-01-01

    Internet technology and Web 2.0 applications have enabled social networking media to expand in ways that link people globally. By fostering communication, social networks hold immense potential for the enhancement of teaching, especially in the business arena. This article defines social networking and provides a framework for understanding the…

  9. Multirate IP traffic transmission in flexible access networks based on optical FFH-CDMA

    DEFF Research Database (Denmark)

    Raddo, Thiago R.; Sanches, Anderson L.; Tafur Monroy, Idelfonso

    2016-01-01

    In this paper, we propose a new IP transmission architecture over optical fast frequency hopping code-division multiple-access (OFFH-CDMA) network capable of supporting multirate transmissions for applications in flexible optical access networks. The proposed network architecture is independent...

  10. 47 CFR 51.311 - Nondiscriminatory access to unbundled network elements.

    Science.gov (United States)

    2010-10-01

    ... elements. 51.311 Section 51.311 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) COMMON... § 51.311 Nondiscriminatory access to unbundled network elements. (a) The quality of an unbundled network element, as well as the quality of the access to the unbundled network element, that an incumbent...

  11. Social Media for Professional Development and Networking Opportunities in Academia

    Science.gov (United States)

    Donelan, Helen

    2016-01-01

    The research reported on in this article explores the use of social media for work-related or professional purposes. In particular, it focuses on the perceptions and use of social media by academics in the UK. The purpose of the research was to explore the potential social media has to facilitate the changing landscape of higher education and…

  12. Optimizing Cooperative Cognitive Radio Networks with Opportunistic Access

    KAUST Repository

    Zafar, Ammar

    2012-09-16

    Optimal resource allocation for cooperative cognitive radio networks with opportunistic access to the licensed spectrum is studied. Resource allocation is based on minimizing the symbol error rate at the receiver. Both the cases of all-participate relaying and selective relaying are considered. The objective function is derived and the constraints are detailed for both scenarios. It is then shown that the objective functions and the constraints are nonlinear and nonconvex functions of the parameters of interest, that is, source and relay powers, symbol time, and sensing time. Therefore, it is difficult to obtain closed-form solutions for the optimal resource allocation. The optimization problem is then solved using numerical techniques. Numerical results show that the all-participate system provides better performance than its selection counterpart, at the cost of greater resources. © 2012 Ammar Zafar et al.

  13. JavaScript Access to DICOM Network and Objects in Web Browser.

    Science.gov (United States)

    Drnasin, Ivan; Grgić, Mislav; Gogić, Goran

    2017-10-01

    Digital imaging and communications in medicine (DICOM) 3.0 standard provides the baseline for the picture archiving and communication systems (PACS). The development of Internet and various communication media initiated demand for non-DICOM access to PACS systems. Ever-increasing utilization of the web browsers, laptops and handheld devices, as opposed to desktop applications and static organizational computers, lead to development of different web technologies. The DICOM standard officials accepted those subsequently as tools of alternative access. This paper provides an overview of the current state of development of the web access technology to the DICOM repositories. It presents a different approach of using HTML5 features of the web browsers through the JavaScript language and the WebSocket protocol by enabling real-time communication with DICOM repositories. JavaScript DICOM network library, DICOM to WebSocket proxy and a proof-of-concept web application that qualifies as a DICOM 3.0 device were developed.

  14. The New Digital Media Value Network: Proposing an Interactive Model of Digital Media Value Activities

    Directory of Open Access Journals (Sweden)

    Sylvia Chan-Olmsted

    2016-07-01

    Full Text Available This study models the dynamic nature of today’s media markets using the framework of value-adding activities in the provision and consumption of media products. The proposed user-centric approach introduces the notion that the actions of external users, social media, and interfaces affect the internal value activities of media firms via a feedback loop, and therefore should themselves be considered value activities. The model also suggests a more comprehensive list of indicators for value assessment.

  15. Steep optical filtering for next generation optical access networks

    Science.gov (United States)

    Korček, Dušan; Müllerová, Jarmila

    2012-01-01

    Future development of optical access technologies expects increasing traffic and bandwidth. The first candidates to improve Gigabit-capable passive optical networks (GPON) are 10-Gigabit-PON (XG-PON) and wavelength-division multiplexing PON (WDM PON). Another possibility for increasing penetration of current PON branch is to extend number of channels provided on one optical fiber for one PON technology. Coexistence of GPON, XG-PON and WDM-PON in the same infrastructure is a most discussed issue concerning passive optical networks nowadays. Therefore, extensive studies are necessary to design proper and low-cost candidates. International Telecommunication Union (ITU) allocates specific wavelength bands for the present status quo and the future development of access technologies. However, within coexistence, it is necessary to protect signals from various PON technologies from interference. A potential barrier to deploying XG-GPONs and WDM PONs with current GPONs is the usage of broadband light sources and sophisticated optical methods of slicing the light source emission into specific wavelength channels. Protective measures comprise the exact allocation of upstream and downstream signal bands for each technology; the so-called guard bands within the wavelength allocation scheme to protect signals; and optionally the usage of wavelength blocking filters. In this contribution, bandpass thin-film filters are numerically presented for hybrid time division/wavelength division multiplexing TDM/WDM (TWDM) and for simple operation. They have been designed to be tunable and as steep as possible to reject the wavelength bands outside those allocated to TWDM-PON. The TWDM-PON filters are proposed to guarantee steep transmission curves in the vicinity of cut-on/cut-off wavelengths of the specific allocated wavelength bands and facilitate migration from legacy GPON and XG-PON to TWDM-PON. Their deployment protects the allocated wavelength bands from the undesirable interference.

  16. Analyzing Social Media and Learning through Content and Social Network Analysis: A Faceted Methodological Approach

    Science.gov (United States)

    Gruzd, Anatoliy; Paulin, Drew; Haythornthwaite, Caroline

    2016-01-01

    In just a short period, social media have altered many aspects of our daily lives, from how we form and maintain social relationships to how we discover, access, and share information online. Now social media are also affecting how we teach and learn. In this paper, we discuss methods that can help researchers and educators evaluate and understand…

  17. Support networks and people with physical disabilities: social inclusion and access to health services

    National Research Council Canada - National Science Library

    Holanda, Cristina Marques de Almeida; De Andrade, Fabienne Louise Juvêncio Paes; Bezerra, Maria Aparecida; Nascimento, João Paulo da Silva; Neves, Robson da Fonseca; Alves, Simone Bezerra; Ribeiro, Kátia Suely Queiroz Silva

    2015-01-01

    This study seeks to identify the formation of social support networks of people with physical disabilities, and how these networks can help facilitate access to health services and promote social inclusion...

  18. Repeated Exposure to Media Violence Is Associated with Diminished Response in an Inhibitory Frontolimbic Network

    OpenAIRE

    Kelly, Christopher R.; Jack Grinband; Joy Hirsch

    2007-01-01

    BACKGROUND: Media depictions of violence, although often claimed to induce viewer aggression, have not been shown to affect the cortical networks that regulate behavior. METHODOLOGY/PRINCIPAL FINDINGS: Using functional magnetic resonance imaging (fMRI), we found that repeated exposure to violent media, but not to other equally arousing media, led to both diminished response in right lateral orbitofrontal cortex (right ltOFC) and a decrease in right ltOFC-amygdala interaction. Reduced function...

  19. The influence of repressive legislation on the structure of a social media network

    OpenAIRE

    Marcoux, Marianne; Lusseau, David

    2013-01-01

    Social media have been widely used to organize citizen movements. In 2012, 75% university and college students in Quebec, Canada, participated in mass protests against an increase in tuition fees, mainly organized using social media. To reduce public disruption, the government introduced special legislation designed to impede protest organization. Here, we show that the legislation changed the behaviour of social media users but not the overall structure of their social network on Twitter. Th...

  20. Evaluation of accessible mineral surface areas for improved prediction of mineral reaction rates in porous media

    Science.gov (United States)

    Beckingham, Lauren E.; Steefel, Carl I.; Swift, Alexander M.; Voltolini, Marco; Yang, Li; Anovitz, Lawrence M.; Sheets, Julia M.; Cole, David R.; Kneafsey, Timothy J.; Mitnick, Elizabeth H.; Zhang, Shuo; Landrot, Gautier; Ajo-Franklin, Jonathan B.; DePaolo, Donald J.; Mito, Saeko; Xue, Ziqiu

    2017-05-01

    The rates of mineral dissolution reactions in porous media are difficult to predict, in part because of a lack of understanding of mineral reactive surface area in natural porous media. Common estimates of mineral reactive surface area used in reactive transport models for porous media are typically ad hoc and often based on average grain size, increased to account for surface roughness or decreased by several orders of magnitude to account for reduced surface reactivity of field as opposed to laboratory samples. In this study, accessible mineral surface areas are determined for a sample from the reservoir formation at the Nagaoka pilot CO2 injection site (Japan) using a multi-scale image analysis based on synchrotron X-ray microCT, SEM QEMSCAN, XRD, SANS, and FIB-SEM. This analysis not only accounts for accessibility of mineral surfaces to macro-pores, but also accessibility through connected micro-pores in smectite, the most abundant clay mineral in this sample. While the imaging analysis reveals that most of the micro- and macro-pores are well connected, some pore regions are unconnected and thus inaccessible to fluid flow and diffusion. To evaluate whether mineral accessible surface area accurately reflects reactive surface area a flow-through core experiment is performed and modeled at the continuum scale. The core experiment is performed under conditions replicating the pilot site and the evolution of effluent solutes in the aqueous phase is tracked. Various reactive surface area models are evaluated for their ability to capture the observed effluent chemistry, beginning with parameter values determined as a best fit to a disaggregated sediment experiment (Beckingham et al., 2016) described previously. Simulations that assume that all mineral surfaces are accessible (as in the disaggregated sediment experiment) over-predict the observed mineral reaction rates, suggesting that a reduction of RSA by a factor of 10-20 is required to match the core flood

  1. The Effect of Information Access Strategy on Power Consumption and Reliability in Wireless Sensor Network

    DEFF Research Database (Denmark)

    Tobgay, Sonam; Olsen, Rasmus Løvenstein; Prasad, Ramjee

    2013-01-01

    This paper examines the effect of different information access strategies on power consumption and information reliability, considering the wireless sensor network as the source of information. Basically, the paper explores three different access strategies, namely; reactive, periodic and hybrid...... and computes power consumption and mismatch probability [1] in each of these access strategies. Based on our study, we make some recommendations when and where, which access strategy is suitable depending upon the application's requirements and network behavior. It also provides the model implementation...

  2. The Public Manager 2.0 : Preparing the Social Media Generation for a Networked Workplace

    OpenAIRE

    Mergel, Ines

    2012-01-01

    This article provides the design of a new student-centered information management course to teach the effective use of social media technologies in the public sector as part of public affairs programs. The goal of this “Government 2.0” course is to provide students with analytical and technological skills to navigate the challenges future public managers are facing in a networked workplace. Social media technologies, such as wikis, blogs, microblogging services, or social networking sites, ha...

  3. Brand interactions and social media: enhancing user loyalty through social networking sites

    OpenAIRE

    Nisar, T.M.; Whitehead, C

    2016-01-01

    This paper aims to investigate how user loyalty can be achieved and maintained through social networking sites. More specifically, we intend to test the relationships between brands, user loyalty and social media. The research thus provides insights into user-brand relationships through social media and argues how loyal customers can be through social networking websites. Although there are considerable numbers of studies about loyalty; there exists very limited work studying user loyalty thr...

  4. Integration of QoS provisioning in home and access networks

    DEFF Research Database (Denmark)

    Popov, Mikhail; Gavler, A.; Sköldström, P.

    2010-01-01

    Approaches for QoS provisioning using UPnP for home networks and GMPLS for access networks are described. A solution for interworking the UPnP and the GMPLS at the residential gateway is proposed.......Approaches for QoS provisioning using UPnP for home networks and GMPLS for access networks are described. A solution for interworking the UPnP and the GMPLS at the residential gateway is proposed....

  5. Examining the use of evidence-based and social media supported tools in freely accessible physical activity intervention websites

    National Research Council Canada - National Science Library

    Vandelanotte, Corneel; Kirwan, Morwenna; Rebar, Amanda; Alley, Stephanie; Short, Camille; Fallon, Luke; Buzza, Gavin; Schoeppe, Stephanie; Maher, Carol; Duncan, Mitch J

    2014-01-01

    ...) and incorporate interactive social media applications (e.g. social networking), but it is unclear to what extent these are being utilized in the publicly available web-based physical activity interventions...

  6. A coevolving model based on preferential triadic closure for social media networks.

    Science.gov (United States)

    Li, Menghui; Zou, Hailin; Guan, Shuguang; Gong, Xiaofeng; Li, Kun; Di, Zengru; Lai, Choy-Heng

    2013-01-01

    The dynamical origin of complex networks, i.e., the underlying principles governing network evolution, is a crucial issue in network study. In this paper, by carrying out analysis to the temporal data of Flickr and Epinions-two typical social media networks, we found that the dynamical pattern in neighborhood, especially the formation of triadic links, plays a dominant role in the evolution of networks. We thus proposed a coevolving dynamical model for such networks, in which the evolution is only driven by the local dynamics-the preferential triadic closure. Numerical experiments verified that the model can reproduce global properties which are qualitatively consistent with the empirical observations.

  7. Differences in media access and use between rural Native American and White children.

    Science.gov (United States)

    Hswen, Yulin; Naslund, John A; Bickham, David S

    2014-01-01

    Native American children experience greater disparities in the number and magnitude of health-related diseases than White children. Multimedia-based health interventions may afford valuable opportunities for reaching this underserved demographic; however, limited data are available describing the use of media technologies among Native Americans. This study characterized diverse media access and use between rural Native American and White children. Surveys were administered to students (n=477) aged 10-15 years in grades 6-8 across four public middle schools in the rural Upper Peninsula of the Midwestern USA state of Michigan. Native American children (n=41) were more likely than White children (n=436) to have a video game system in their bedroom (65.9% vs 45.4%; p=0.01) and watch more minutes of television on Saturdays (110.3±91.7 vs 80.7±80.8; p=0.03). Native American children also had fewer computers within the home (1.20±0.81 vs 1.68±1.21; p=0.01) than White children and less household internet access (75.6% vs 87.1%; p=0.04), but demonstrated more use in minutes after school (79.9±97.9 vs 51.1±71.6; p=0.02) and on Saturdays (92.6±107.4 vs 60.0±85.1; p=0.02). This represents the first cross-cultural comparison of media access and use between Native American and White children from rural Michigan. Greater computer and internet use observed among the Native American children surveyed in this study supports the use of web-based public health initiatives aimed at reducing health disparities within this vulnerable group.

  8. Mapping Russian Media Network: Media’s Role in Russian Foreign Policy and Decision-making

    Science.gov (United States)

    2017-06-14

    influence strategy. In addition, we highlight Russian decision-making and messaging through four distinct past and future scenarios along the spectrum of...instrument and lever of influence . The role of media in promoting Russian foreign policy and exerting the influence of President Vladimir Putin has...examine the role that Russia’s media and messaging plays in external influence . In addition, we highlight that while media is a key instrument of

  9. Tensions between Individual Use and Network Adoption of Social Media Platforms

    DEFF Research Database (Denmark)

    Srinivasan, Nikhil; Damsgaard, Jan

    2013-01-01

    by interviewing individuals within a university context. An analysis of the vignettes and individual use behaviors highlights the tension between network-based adoption of social media platforms and the constraints that the network places on individual use of the platform.......Social media have diffused into the everyday lives of many but still pose challenges to individuals regarding use of these platforms. This paper explores the multiple manners in which social media platforms gets employed by individuals based on an examination of 4 vignettes generated...

  10. A Hub Location Problem with Fully Interconnected Backbone and Access Networks

    DEFF Research Database (Denmark)

    Thomadsen, Tommy; Larsen, Jesper

    2007-01-01

    This paper considers the design of two-layered fully interconnected networks. A two-layered network consists of clusters of nodes, each defining an access network and a backbone network. We consider the integrated problem of determining the access networks and the backbone network simultaneously...... problems. We obtain superior bounds using the column generation approach than with the linear programming relaxation. The column generation method is therefore developed into an exact approach using the Branch-and-Price framework. With this approach we are able to solve problems consisting of up to 25...

  11. GPON: the next big thing in optical access networks

    Science.gov (United States)

    Marmur, Oren; Shraga, Eyal

    2004-04-01

    This paper contains a comprehensive review of the various Passive Optical Network (PON) technologies in the marketplace today, namely APON, EPON and GPON, and draws an in-depth comparison between them. Following a review of the history of the various PON flavors, as well as the service requirements set forth by service providers, the emerging Gigabit PON (GPON) technology is examined in detail. System performance between the various protocols is compared using efficiency and scalability factors, and conclusions are drawn as to the overall throughput efficiency of and cost influence on the solution. GPON carries a two-fold promise of both higher bit rates and higher efficiency when carrying multiple services over the PON. It offers a scalable framing structure from 622Mb/s to 2.5Gb/s, as well as support for asymmetric bit rates, exceptionally high bandwidth utilization for any type of service and a variant of standard ITU-T Generic Framing Protocol (GFP) encapsulation of any type of service (both TDM and packet) onto a synchronous transport protocol. It is shown that in the worst-case scenario, based upon the most conservative assumptions regarding traffic distribution, GPON is substantially more efficient, with an overall efficiency of 93% compared to 71% with APON and 49% with EPON. Using a more detailed analysis based upon a traffic model provided by the service providers within the full service access networks (FSAN) consortium, it is shown in quantitative terms that GPON offers exceptionally higher bandwidth for the entire range of applications when compared to both APON and, especially, EPON, resulting in substantially lower cost per bit and a much faster payback period.

  12. Access pricing for transmission networks: Hypotheses and empirical evidence

    Energy Technology Data Exchange (ETDEWEB)

    Martoccia, Maria [Decision Technology Centre, London (United Kingdom)

    1999-08-01

    The sectors characterised by the use of transmission or transport networks as inputs of production (electricity, gas, telecommunications) have long been considered as natural monopolies. Thanks to the technological innovations which have modified the economics of production (as in electricity generation) or that have driven the development of high value added services (as in telecommunications), the boundaries of the old natural monopolies have been eroded by the presence of operators potentially able to compete in national and international markets. The objective is to delineate, by analysing the more significant theoretical contributions and some of the restructuring experiences of the sector in question, the possible regulatory solutions which, in the perspective of a `European market` for electricity, makes the management and the expansion of the transmission networks adequate for the `open access` of national electricity sectors. The analysis of some mature experiences, such as in Chile, Argentina, the UK and Norway, in the second section, will offer a useful support to this evaluation. The regulatory solution here adopted will be analysed, in particular, with reference to the two main problems outlined above: on the one hand, the problem of providing through prices the necessary information about the opportunities of using the transmission assets; and on the other hand, the problem of defining an efficient incentive mechanism for the behaviour of the monopolist (the owner of the transmission assets). Finally, by considering the limits found in the solutions explored in these models, we will try, in the third section, to delineate the evolution that the regulation of the analysed sectors could follow, in an attempt to make the optimal solution defined in the first section consistent with the imperfections of the real scenarios. (EHS)

  13. Repeated exposure to media violence is associated with diminished response in an inhibitory frontolimbic network.

    Science.gov (United States)

    Kelly, Christopher R; Grinband, Jack; Hirsch, Joy

    2007-12-05

    Media depictions of violence, although often claimed to induce viewer aggression, have not been shown to affect the cortical networks that regulate behavior. Using functional magnetic resonance imaging (fMRI), we found that repeated exposure to violent media, but not to other equally arousing media, led to both diminished response in right lateral orbitofrontal cortex (right ltOFC) and a decrease in right ltOFC-amygdala interaction. Reduced function in this network has been previously associated with decreased control over a variety of behaviors, including reactive aggression. Indeed, we found reduced right ltOFC responses to be characteristic of those subjects that reported greater tendencies toward reactive aggression. Furthermore, the violence-induced reduction in right ltOFC response coincided with increased throughput to behavior planning regions. These novel findings establish that even short-term exposure to violent media can result in diminished responsiveness of a network associated with behaviors such as reactive aggression.

  14. Labeling Actors and Uncovering Causal Accounts of Their States in Social Networks and Social Media

    Science.gov (United States)

    Bui, Ngot P.

    2016-01-01

    The emergence of social networks and social media has resulted in exponential increase in the amount of data that link diverse types of richly structured digital objects e.g., individuals, articles, images, videos, music, etc. Such data are naturally represented as heterogeneous networks with multiple types of objects e.g., actors, video,…

  15. Pore-network modeling of solute transport and biofilm growth in porous media

    NARCIS (Netherlands)

    Qin, Chao Zhong; Hassanizadeh, S. Majid

    2015-01-01

    In this work, a pore-network (PN) model for solute transport and biofilm growth in porous media was developed. Compared to previous studies of biofilm growth, it has two new features. First, the constructed pore network gives a better representation of a porous medium. Second, instead of using a

  16. Design of Active Queue Management for Robust Control on Access Router for Heterogeneous Networks

    Directory of Open Access Journals (Sweden)

    Åhlund Christer

    2011-01-01

    Full Text Available The Internet architecture is a packet switching technology that allows dynamic sharing of bandwidth among different flows with in an IP network. Packets are stored and forwarded from one node to the next until reaching their destination. Major issues in this integration are congestion control and how to meet different quality of service requirements associated with various services. In other words streaming media quality degrades with increased packet delay and jitter caused by network congestion. To mitigate the impact of network congestion, various techniques have been used to improve multimedia quality and one of those techniques is Active Queue Management (AQM. Access routers require a buffer to hold packets during times of congestion. A large buffer can absorb the bursty arrivals, and this tends to increase the link utilizations but results in higher queuing delays. Traffic burstiness has a considerable negative impact on network performance. AQM is now considered an effective congestion control mechanism for enhancing transport protocol performance over wireless links. In order to have good link utilization, it is necessary for queues to adapt to varying traffic loads. This paper considers a particular scheme which is called Adaptive AQM (AAQM and studies its performance in the presence of feedback delays and its ability to maintain a small queue length as well as its robustness in the presence of traffic burstiness. The paper also presents a method based on the well-known Markov Modulated Poisson Process (MPP to capture traffic burstiness and buffer occupancy. To demonstrate the generality of the presented method, an analytic model is described and verified by extensive simulations of different adaptive AQM algorithms. The analysis and simulations show that AAQM outperforms the other AQMs with respect to responsiveness and robustness.

  17. Algorithmic PON/P2P FTTH Access Network Design for CAPEX Minimization

    DEFF Research Database (Denmark)

    Papaefthimiou, Kostantinos; Tefera, Yonas; Mihylov, Dimitar

    2013-01-01

    Due to the emergence of high bandwidth-requiring services, telecommunication operators (telcos) are called to upgrade their fixed access network. In order to keep up with the competition, they must consider different optical access network solutions with Fiber To The Home (FTTH) as the prevailing...

  18. Peer Relations and Access to Capital in the Mathematics Classroom: A Bourdieusian Social Network Analysis

    Science.gov (United States)

    Choudry, Sophina; Williams, Julian; Black, Laura

    2017-01-01

    The aim of this article is to explore the structure of social capital in peer networks and its relation to the unequal access of educational resources within mathematics classrooms. We hypothesise that learners can gain access to mathematics through friendship networks which provide more or less help from peers that might sustain (or curtail)…

  19. Energy Efficiency in TDMA-Based Next-Generation Passive Optical Access Networks

    KAUST Repository

    Dhaini, Ahmad R.

    2014-06-01

    Next-generation passive optical network (PON) has been considered in the past few years as a cost-effective broadband access technology. With the ever-increasing power saving concern, energy efficiency has been an important issue in its operations. In this paper, we propose a novel sleep-time sizing and scheduling framework for the implementation of green bandwidth allocation (GBA) in TDMA-PONs. The proposed framework leverages the batch-mode transmission feature of GBA to minimize the overhead due to frequent ONU on-off transitions. The optimal sleeping time sequence of each ONU is determined in every cycle without violating the maximum delay requirement. With multiple ONUs possibly accessing the shared media simultaneously, a collision may occur. To address this problem, we propose a new sleep-time sizing mechanism, namely Sort-And-Shift (SAS), in which the ONUs are sorted according to their expected transmission start times, and their sleep times are shifted to resolve any possible collision while ensuring maximum energy saving. Results show the effectiveness of the proposed framework and highlight the merits of our solutions.

  20. Detection of strong attractors in social media networks

    National Research Council Canada - National Science Library

    Qasem, Ziyaad; Jansen, Marc; Hecking, Tobias; Hoppe, H Ulrich

    2016-01-01

    Detection of influential actors in social media such as Twitter or Facebook plays an important role for improving the quality and efficiency of work and services in many fields such as education and marketing...

  1. Power, surveillance and digital network media in organizations

    DEFF Research Database (Denmark)

    Tække, Jesper

    With the focus on organizations, this article describes power in relation to mediated surveillance using Luhmann’s systems theory, poststructuralist theory and theory of media sociography. It aims to sketch out the main issues in contemporary surveillance discourse and illustrate the current...... situation, as well as discuss surveillance from the perspective of poststructuralist theory in relation to Luhmann’s concepts of trust, risk and especially power. The underlying media sociographical question is which storing-, retrieving-, localisation- and temporal possibilities for communication...

  2. Knowledge Access in Rural Inter-connected Areas Network ...

    International Development Research Centre (IDRC) Digital Library (Canada)

    This phase will endeavor to expand the existing network to include two thematic networks on food security and rural enterprise, respectively. A third thematic network - on knowledge management strategies - will play an advisory and support role to the larger network. Project activities will include a call for research proposals ...

  3. How Researchers Use Social Media to Promote their Research and Network with Industry

    Directory of Open Access Journals (Sweden)

    Päivi Jaring

    2017-08-01

    Full Text Available Social media is now an essential information and interaction channel. Companies advertise and sell their products and services through social media, but this channel has not been so commonly applied to the task of selling knowledge and research work. This article studies the use of social media by researchers to promote their research and network with product developers in industry, and it presents a model of the use of social media by researchers. The data for this research was obtained by interviewing individual researchers of a research organization and surveying product developers from industry. The findings show that social media is seen as a good source of new information and contacts, and it is suitable for promoting awareness of research services and results. The results show that the speed and intensity of social media present challenges for researchers, but by being active in posting content and participating in discussions, researchers can derive benefits and enhance their personal reputations.

  4. Modeling Dynamics of Diffusion Across Heterogeneous Social Networks: News Diffusion in Social Media

    OpenAIRE

    Peter Christen; David Newth; Minkyoung Kim

    2013-01-01

    Diverse online social networks are becoming increasingly interconnected by sharing information. Accordingly, emergent macro-level phenomena have been observed, such as the synchronous spread of information across different types of social media. Attempting to analyze the emergent global behavior is impossible from the examination of a single social platform, and dynamic influences between different social networks are not negligible. Furthermore, the underlying structural property of networks...

  5. Exploratory Social Network Analysis of Management Faculty students on social media Facebook

    OpenAIRE

    Loušová, Petra

    2013-01-01

    The aim of the bachelor thesis is the introduction of modern approaches in analysis social networks. In theoretical part there is characterized various social media used in both the Czech Republic and in the world. Additionally discussed are fundamental elements of social networking and the ability of analysis using software. In practical part are these basic approaches applied for an exploratory analysis of the social network of students of University of Economics, Faculty of Management in s...

  6. Enhancing Access to Land Remote Sensing Data through Mainstream Social Media Channels

    Science.gov (United States)

    Sohre, T.; Maiersperger, T.

    2011-12-01

    Social media tools are changing the way that people discover information, communicate, and collaborate. Government agencies supporting the Land Remote Sensing user community have begun taking advantage of standard social media tools and capabilities. National Aeronautics and Space Administration (NASA) Earth Observing System (EOS) data centers have started providing outreach utilizing services including Facebook, Twitter, and YouTube videos. Really Simple Syndication (RSS) Feeds have become more standard means of sharing information, and a DataCasting tool was created as a NASA Technology Infusion effort to make RSS-based technology for accessing Earth Science information available. The United States Geological Survey (USGS) has also started using social media to allow the community access to news feeds and real-time earthquake alerts; listen to podcasts; get updates on new USGS publications, videos, and photographs; and more. Twitter feeds have been implemented in 2011 for the USGS Land Cover and Landsat user communities. In early 2011, the NASA Land Processes Distributed Active Archive Center (LP DAAC) user working group suggested the investigation of concepts for creating and distributing "bundles" of data, which would aggregate theme-based data sets from multiple sources. The LP DAAC is planning to explore the use of standard social bookmarking tools to support community developed bundles through the use of tools such as Delicious, Digg, or StumbleUpon. This concept would allow science users to organize and discover common links to data resources based on community developed tags, or a folksonomy. There are challenges that will need to be addressed such as maintaining the quality of tags but a social bookmarking system may have advantages over traditional search engines or formal ontologies for identifying and labeling various data sets relevant to a theme. As classification is done by the community of scientists who understand the data, the tagged data sets

  7. Forecasting influenza-like illness dynamics for military populations using neural networks and social media.

    Directory of Open Access Journals (Sweden)

    Svitlana Volkova

    Full Text Available This work is the first to take advantage of recurrent neural networks to predict influenza-like illness (ILI dynamics from various linguistic signals extracted from social media data. Unlike other approaches that rely on timeseries analysis of historical ILI data and the state-of-the-art machine learning models, we build and evaluate the predictive power of neural network architectures based on Long Short Term Memory (LSTMs units capable of nowcasting (predicting in "real-time" and forecasting (predicting the future ILI dynamics in the 2011 - 2014 influenza seasons. To build our models we integrate information people post in social media e.g., topics, embeddings, word ngrams, stylistic patterns, and communication behavior using hashtags and mentions. We then quantitatively evaluate the predictive power of different social media signals and contrast the performance of the-state-of-the-art regression models with neural networks using a diverse set of evaluation metrics. Finally, we combine ILI and social media signals to build a joint neural network model for ILI dynamics prediction. Unlike the majority of the existing work, we specifically focus on developing models for local rather than national ILI surveillance, specifically for military rather than general populations in 26 U.S. and six international locations., and analyze how model performance depends on the amount of social media data available per location. Our approach demonstrates several advantages: (a Neural network architectures that rely on LSTM units trained on social media data yield the best performance compared to previously used regression models. (b Previously under-explored language and communication behavior features are more predictive of ILI dynamics than stylistic and topic signals expressed in social media. (c Neural network models learned exclusively from social media signals yield comparable or better performance to the models learned from ILI historical data, thus

  8. Forecasting influenza-like illness dynamics for military populations using neural networks and social media.

    Science.gov (United States)

    Volkova, Svitlana; Ayton, Ellyn; Porterfield, Katherine; Corley, Courtney D

    2017-01-01

    This work is the first to take advantage of recurrent neural networks to predict influenza-like illness (ILI) dynamics from various linguistic signals extracted from social media data. Unlike other approaches that rely on timeseries analysis of historical ILI data and the state-of-the-art machine learning models, we build and evaluate the predictive power of neural network architectures based on Long Short Term Memory (LSTMs) units capable of nowcasting (predicting in "real-time") and forecasting (predicting the future) ILI dynamics in the 2011 - 2014 influenza seasons. To build our models we integrate information people post in social media e.g., topics, embeddings, word ngrams, stylistic patterns, and communication behavior using hashtags and mentions. We then quantitatively evaluate the predictive power of different social media signals and contrast the performance of the-state-of-the-art regression models with neural networks using a diverse set of evaluation metrics. Finally, we combine ILI and social media signals to build a joint neural network model for ILI dynamics prediction. Unlike the majority of the existing work, we specifically focus on developing models for local rather than national ILI surveillance, specifically for military rather than general populations in 26 U.S. and six international locations., and analyze how model performance depends on the amount of social media data available per location. Our approach demonstrates several advantages: (a) Neural network architectures that rely on LSTM units trained on social media data yield the best performance compared to previously used regression models. (b) Previously under-explored language and communication behavior features are more predictive of ILI dynamics than stylistic and topic signals expressed in social media. (c) Neural network models learned exclusively from social media signals yield comparable or better performance to the models learned from ILI historical data, thus, signals from

  9. Formal Specification and Validation of Secure Connection Establishment in a Generic Access Network Scenario

    DEFF Research Database (Denmark)

    Fleischer, Paul; Kristensen, Lars Michael

    2008-01-01

    The Generic Access Network (GAN) architecture is defined by the 3rd Generation Partnership Project (3GPP), and allows telephone services, such as SMS and voice-calls, to be accessed via generic IP networks. The main usage of this is to allow mobile phones to use WiFi in addition to the usual GSM...... network. The GAN specification relies on the Internet Protocol Security layer (IPSec) and the Internet Key Exchange protocol (IKEv2) to provide encryption across IP networks, and thus avoid compromising the security of the telephone networks. The detailed usage of these two Internet protocols (IPSec...

  10. Experimental realization of an entanglement access network and secure multi-party computation

    Science.gov (United States)

    Chang, Xiuying; Deng, Donglin; Yuan, Xinxing; Hou, Panyu; Huang, Yuanyuan; Duan, Luming; Department of Physics, University of Michigan Collaboration; Center for Quantum Information in Tsinghua University Team

    2017-04-01

    To construct a quantum network with many end users, it is critical to have a cost-efficient way to distribute entanglement over different network ends. We demonstrate an entanglement access network, where the expensive resource, the entangled photon source at the telecom wavelength and the core communication channel, is shared by many end users. Using this cost-efficient entanglement access network, we report experimental demonstration of a secure multiparty computation protocol, the privacy-preserving secure sum problem, based on the network quantum cryptography.

  11. The Role of Social Network Locations in the College Access Mentoring of Urban Youth

    Science.gov (United States)

    Ahn, June

    2010-01-01

    This study uses social network analysis to describe the social network of college mentors in a college access program. Urban students in the program are paired with college mentors-students, professors, and other institutional agents-to help improve their college going process. The study analyzes the social networks within which the mentors are…

  12. Integrated self-management for future radio access networks: Vision and key challenges

    NARCIS (Netherlands)

    Eisenblätter, A.; Conzalez Rodríguez, B.; Gunnarsson, F.; Kürner, T.; Litjens, R.; Sas, B.; Sayrac, B.; Schmelz, L.C.; Willcock, C.

    2013-01-01

    Future radio access networks will require new self-management solutions to handle the increasing operational complexity caused by multi-technology and multi-layer deployments. Current networks already include stand-alone SON (Self-Organizing Networks) solutions, but these are not sufficient to

  13. Provision of metro ethernet services using a reconfigurable photonic access network

    NARCIS (Netherlands)

    Roy, R.; van Etten, Wim

    2007-01-01

    The paper proposes a design for traffic engineering to provide Ethernet services using an extended access network. Ethernet has remained the dominant technology for Local Area and Enterprise Networks, the use of Ethernet in metro networks has seen significant interest of late to provide for end to

  14. Mapping Russian Media Network: Media’s Role in Russian Foreign Policy and Decision-Making

    Science.gov (United States)

    2017-06-14

    New Zealand ), but also in non-Western countries where other languages are predominant, such as India, Pakistan, and Hong Kong. Of course, English is...press conference. July 10, 2015. http://kremlin.ru/events/president/ news /49909/photos Approved by: June 2017 Ken E. Gause, Director...Russia’s media and messaging plays in external influence. In addition, we highlight that while media is a key instrument of influence, culture , politics

  15. COLLABORATIVE PROBLEM SOLVING USING PUBLIC SOCIAL NETWORK MEDIA: ANALYZING STUDENT INTERACTION AND ITS IMPACT TO LEARNING PROCESS

    OpenAIRE

    Melvin Ballera; Ismail Ateya Lukandu; Abdalla Radwan

    2013-01-01

    This paper examines the use of social network media at three aspects in African and Libyan perspective. Firstly, to use social network media as an open network learning environment that provide service for interaction necessary for learners to support socialization and collaboration during problem solving. Secondly, to use social media as a tool to support blended learning in e-learning system and encourage non-native English students to express their ideas and fill the gap of communication p...

  16. User recommendation in healthcare social media by assessing user similarity in heterogeneous network.

    Science.gov (United States)

    Jiang, Ling; Yang, Christopher C

    2017-09-01

    The rapid growth of online health social websites has captured a vast amount of healthcare information and made the information easy to access for health consumers. E-patients often use these social websites for informational and emotional support. However, health consumers could be easily overwhelmed by the overloaded information. Healthcare information searching can be very difficult for consumers, not to mention most of them are not skilled information searcher. In this work, we investigate the approaches for measuring user similarity in online health social websites. By recommending similar users to consumers, we can help them to seek informational and emotional support in a more efficient way. We propose to represent the healthcare social media data as a heterogeneous healthcare information network and introduce the local and global structural approaches for measuring user similarity in a heterogeneous network. We compare the proposed structural approaches with the content-based approach. Experiments were conducted on a dataset collected from a popular online health social website, and the results showed that content-based approach performed better for inactive users, while structural approaches performed better for active users. Moreover, global structural approach outperformed local structural approach for all user groups. In addition, we conducted experiments on local and global structural approaches using different weight schemas for the edges in the network. Leverage performed the best for both local and global approaches. Finally, we integrated different approaches and demonstrated that hybrid method yielded better performance than the individual approach. The results indicate that content-based methods can effectively capture the similarity of inactive users who usually have focused interests, while structural methods can achieve better performance when rich structural information is available. Local structural approach only considers direct connections

  17. Uncovering the differences in linguistic network dynamics of book and social media texts.

    Science.gov (United States)

    Türker, İlker; Şehirli, Eftal; Demiral, Emrullah

    2016-01-01

    Complex network studies span a large variety of applications including linguistic networks. To investigate the differences in book and social media texts in terms of linguistic typology, we constructed both sequential and sentence collocation networks of book, Facebook and Twitter texts with undirected and weighted edges. The comparisons are performed using the basic parameters like average degree, modularity, average clustering coefficient, average path length, diameter, average link weight etc. We also presented the distribution graphs for node degrees, edge weights and maximum degree differences of the pairing nodes. The degree difference occurrences are furtherly detailed with the grayscale percentile plots with respect to the edge weights. We linked the network analysis with linguistic aspects like word and sentence length distributions. We concluded that linguistic typology demonstrates a formal usage in book that slightly deviates to informal in Twitter. Facebook interpolates between these media by the means of network parameters, while the informality of Twitter is mostly influenced by the character limitations.

  18. Self-management for unified heterogeneous radio access networks

    NARCIS (Netherlands)

    Litjens, R.; Gunnarsson, F.; Sayrac, B.; Spaey, K.; Willcock, C.; Eisenblätter, A.; Rodríguez, B.G.; Kürner, T.

    2013-01-01

    The development of self-management solutions for (multi-technology, multi-layer) mobile communication networks is driven by their increasing operational complexity. Initial stand-alone SON (Self-Organizing Networks) solutions are already available, but are not sufficient to handle the networks of

  19. A Context-Aware Adaptive Streaming Media Distribution System in a Heterogeneous Network with Multiple Terminals

    Directory of Open Access Journals (Sweden)

    Yepeng Ni

    2016-01-01

    Full Text Available We consider the problem of streaming media transmission in a heterogeneous network from a multisource server to home multiple terminals. In wired network, the transmission performance is limited by network state (e.g., the bandwidth variation, jitter, and packet loss. In wireless network, the multiple user terminals can cause bandwidth competition. Thus, the streaming media distribution in a heterogeneous network becomes a severe challenge which is critical for QoS guarantee. In this paper, we propose a context-aware adaptive streaming media distribution system (CAASS, which implements the context-aware module to perceive the environment parameters and use the strategy analysis (SA module to deduce the most suitable service level. This approach is able to improve the video quality for guarantying streaming QoS. We formulate the optimization problem of QoS relationship with the environment parameters based on the QoS testing algorithm for IPTV in ITU-T G.1070. We evaluate the performance of the proposed CAASS through 12 types of experimental environments using a prototype system. Experimental results show that CAASS can dynamically adjust the service level according to the environment variation (e.g., network state and terminal performances and outperforms the existing streaming approaches in adaptive streaming media distribution according to peak signal-to-noise ratio (PSNR.

  20. The influence of repressive legislation on the structure of a social media network

    CERN Document Server

    Marcoux, Marianne

    2013-01-01

    Social media have been widely used to organize citizen movements. In 2012, 75% university and college students in Quebec, Canada, participated in mass protests against an increase in tuition fees, mainly organized using social media. To reduce public disruption, the government introduced special legislation designed to impede protest organization. Here, we show that the legislation changed the behaviour of social media users but not the overall structure of their social network on Twitter. Thus, users were still able to spread information to efficiently organize demonstrations using their social network. This natural experiment shows the power of social media in political mobilization, as well as behavioural flexibility in information flow over a large number of individuals.

  1. #YesYouCanHazPDF: How Social Media and Networking Are Changing the Research Process

    OpenAIRE

    Gardner, Gabriel; Gardner, Carolyn C.

    2014-01-01

    Social media is being used by libraries and archives in several innovative ways to drive users to unique collections and other content. At the same time, social networking (broadly understood) is changing online research, mainly by people circumventing libraries (on one end of a transaction) in order to obtain copyrighted information via crowd-sourcing. Finally, social media is changing the conception of a "good" or "influential" article - the rise of alternative metrics to citation counting,...

  2. New mothers and media use: associations between blogging, social networking, and maternal well-being.

    Science.gov (United States)

    McDaniel, Brandon T; Coyne, Sarah M; Holmes, Erin K

    2012-10-01

    Drawing on Bronfenbrenner's ecological theory and prior empirical research, the current study examines the way that blogging and social networking may impact feelings of connection and social support, which in turn could impact maternal well-being (e.g., marital functioning, parenting stress, and depression). One hundred and fifty-seven new mothers reported on their media use and various well-being variables. On average, mothers were 27 years old (SD = 5.15) and infants were 7.90 months old (SD = 5.21). All mothers had access to the Internet in their home. New mothers spent approximately 3 hours on the computer each day, with most of this time spent on the Internet. Findings suggested that frequency of blogging predicted feelings of connection to extended family and friends which then predicted perceptions of social support. This in turn predicted maternal well-being, as measured by marital satisfaction, couple conflict, parenting stress, and depression. In sum, blogging may improve new mothers' well-being, as they feel more connected to the world outside their home through the Internet.

  3. Experimental demonstration of OpenFlow-enabled media ecosystem architecture for high-end applications over metro and core networks.

    Science.gov (United States)

    Ntofon, Okung-Dike; Channegowda, Mayur P; Efstathiou, Nikolaos; Rashidi Fard, Mehdi; Nejabati, Reza; Hunter, David K; Simeonidou, Dimitra

    2013-02-25

    In this paper, a novel Software-Defined Networking (SDN) architecture is proposed for high-end Ultra High Definition (UHD) media applications. UHD media applications require huge amounts of bandwidth that can only be met with high-capacity optical networks. In addition, there are requirements for control frameworks capable of delivering effective application performance with efficient network utilization. A novel SDN-based Controller that tightly integrates application-awareness with network control and management is proposed for such applications. An OpenFlow-enabled test-bed demonstrator is reported with performance evaluations of advanced online and offline media- and network-aware schedulers.

  4. Logical optical line terminal technologies towards flexible and highly reliable metro- and access-integrated networks

    Science.gov (United States)

    Okamoto, Satoru; Sato, Takehiro; Yamanaka, Naoaki

    2017-01-01

    In this paper, flexible and highly reliable metro and access integrated networks with network virtualization and software defined networking technologies will be presented. Logical optical line terminal (L-OLT) technologies and active optical distribution networks (ODNs) are the key to introduce flexibility and high reliability into the metro and access integrated networks. In the Elastic Lambda Aggregation Network (EλAN) project which was started in 2012, a concept of the programmable optical line terminal (P-OLT) has been proposed. A role of the P-OLT is providing multiple network services that have different protocols and quality of service requirements by single OLT box. Accommodated services will be Internet access, mobile front-haul/back-haul, data-center access, and leased line. L-OLTs are configured within the P-OLT box to support the functions required for each network service. Multiple P-OLTs and programmable optical network units (P-ONUs) are connected by the active ODN. Optical access paths which have flexible capacity are set on the ODN to provide network services from L-OLT to logical ONUs (L-ONUs). The L-OLT to L-ONU path on the active ODN provides a logical connection. Therefore, introducing virtualization technologies becomes possible. One example is moving an L-OLT from one P-OLT to another P-OLT like a virtual machine. This movement is called L-OLT migration. The L-OLT migration provides flexible and reliable network functions such as energy saving by aggregating L-OLTs to a limited number of P-OLTs, and network wide optical access path restoration. Other L-OLT virtualization technologies and experimental results will be also discussed in the paper.

  5. Design mobile satellite system architecture as an integral part of the cellular access digital network

    Science.gov (United States)

    Chien, E. S. K.; Marinho, J. A.; Russell, J. E., Sr.

    1988-01-01

    The Cellular Access Digital Network (CADN) is the access vehicle through which cellular technology is brought into the mainstream of the evolving integrated telecommunications network. Beyond the integrated end-to-end digital access and per call network services provisioning of the Integrated Services Digital Network (ISDN), the CADN engenders the added capability of mobility freedom via wireless access. One key element of the CADN network architecture is the standard user to network interface that is independent of RF transmission technology. Since the Mobile Satellite System (MSS) is envisioned to not only complement but also enhance the capabilities of the terrestrial cellular telecommunications network, compatibility and interoperability between terrestrial cellular and mobile satellite systems are vitally important to provide an integrated moving telecommunications network of the future. From a network standpoint, there exist very strong commonalities between the terrestrial cellular system and the mobile satellite system. Therefore, the MSS architecture should be designed as an integral part of the CADN. This paper describes the concept of the CADN, the functional architecture of the MSS, and the user-network interface signaling protocols.

  6. A cost model for broadband access networks: FTTx versus WiMAX

    Science.gov (United States)

    Pereira, João Paulo Ribeiro

    2007-09-01

    Local communities and governments are taking various steps to fight the so-called "digital divide" between well served urban communities and undeserved areas. In order to make broadband access available to these under served areas, several technical solutions are available with the capacity to provide high speed Internet access, video, telephony services, etc. This paper presents a cost-model and a tool for the evaluation of broadband access technologies (xDSL, HFC, FTTx, WiMAX, PLC and satellite), and compares two technologies: FTTx and WiMAX. Our tool compares these different access technologies in different scenarios, and examining the capital expense and deployment of building access networks with the same requisite performance using each technology. The cost model is limited to the access part of the network. The results obtained by our evaluation tool give the possibility to compare several BB access technologies, and support the decision about which is the better technological solution for a given scenario

  7. A multi-scale network method for two-phase flow in porous media

    Energy Technology Data Exchange (ETDEWEB)

    Khayrat, Karim, E-mail: khayratk@ifd.mavt.ethz.ch; Jenny, Patrick

    2017-08-01

    Pore-network models of porous media are useful in the study of pore-scale flow in porous media. In order to extract macroscopic properties from flow simulations in pore-networks, it is crucial the networks are large enough to be considered representative elementary volumes. However, existing two-phase network flow solvers are limited to relatively small domains. For this purpose, a multi-scale pore-network (MSPN) method, which takes into account flow-rate effects and can simulate larger domains compared to existing methods, was developed. In our solution algorithm, a large pore network is partitioned into several smaller sub-networks. The algorithm to advance the fluid interfaces within each subnetwork consists of three steps. First, a global pressure problem on the network is solved approximately using the multiscale finite volume (MSFV) method. Next, the fluxes across the subnetworks are computed. Lastly, using fluxes as boundary conditions, a dynamic two-phase flow solver is used to advance the solution in time. Simulation results of drainage scenarios at different capillary numbers and unfavourable viscosity ratios are presented and used to validate the MSPN method against solutions obtained by an existing dynamic network flow solver.

  8. Modeling Dynamics of Diffusion Across Heterogeneous Social Networks: News Diffusion in Social Media

    Directory of Open Access Journals (Sweden)

    Peter Christen

    2013-10-01

    Full Text Available Diverse online social networks are becoming increasingly interconnected by sharing information. Accordingly, emergent macro-level phenomena have been observed, such as the synchronous spread of information across different types of social media. Attempting to analyze the emergent global behavior is impossible from the examination of a single social platform, and dynamic influences between different social networks are not negligible. Furthermore, the underlying structural property of networks is important, as it drives the diffusion process in a stochastic way. In this paper, we propose a macro-level diffusion model with a probabilistic approach by combining both the heterogeneity and structural connectivity of social networks. As real-world phenomena, we explore instances of news diffusion across different social media platforms from a dataset that contains over 386 million web documents covering a one-month period in early 2011. We find that influence between different media types is varied by the context of information. News media are the most influential in the arts and economy categories, while social networking sites (SNS and blog media are in the politics and culture categories, respectively. Furthermore, controversial topics, such as political protests and multiculturalism failure, tend to spread concurrently across social media, while entertainment topics, such as film releases and celebrities, are more likely driven by interactions within single social platforms. We expect that the proposed model applies to a wider class of diffusion phenomena in diverse fields and that it provides a way of interpreting the dynamics of diffusion in terms of the strength and directionality of influences among populations.

  9. Transport network extensions for accessibility analysis in geographic information systems

    NARCIS (Netherlands)

    Jong, Tom de; Tillema, T.

    2005-01-01

    In many developed countries high quality digital transport networks are available for GIS based analysis. Partly this is due to the requirements of route planning software for internet and car navigation systems. Properties of these networks consist among others of road quality attributes,

  10. Resource Sharing in Heterogeneous and Cloud Radio Access Networks

    DEFF Research Database (Denmark)

    Zakrzewska, Anna; Iversen, Villy Bæk

    2012-01-01

    This paper analyzes performance of cellular systems with shared resources, where the network with overlapping cells is modeled as a circuit switched network with direct routing. The influence of the degree of sharing, represented by cell overlap percentage, on the call blocking probability is inv...

  11. Detecting Rumors Through Modeling Information Propagation Networks in a Social Media Environment.

    Science.gov (United States)

    Liu, Yang; Xu, Songhua; Tourassi, Georgia

    2015-01-01

    In the midst of today's pervasive influence of social media content and activities, information credibility has increasingly become a major issue. Accordingly, identifying false information, e.g. rumors circulated in social media environments, attracts expanding research attention and growing interests. Many previous studies have exploited user-independent features for rumor detection. These prior investigations uniformly treat all users relevant to the propagation of a social media message as instances of a generic entity. Such a modeling approach usually adopts a homogeneous network to represent all users, the practice of which ignores the variety across an entire user population in a social media environment. Recognizing this limitation of modeling methodologies, this study explores user-specific features in a social media environment for rumor detection. The new approach hypothesizes that whether a user tends to spread a rumor is dependent upon specific attributes of the user in addition to content characteristics of the message itself. Under this hypothesis, information propagation patterns of rumors versus those of credible messages in a social media environment are systematically differentiable. To explore and exploit this hypothesis, we develop a new information propagation model based on a heterogeneous user representation for rumor recognition. The new approach is capable of differentiating rumors from credible messages through observing distinctions in their respective propagation patterns in social media. Experimental results show that the new information propagation model based on heterogeneous user representation can effectively distinguish rumors from credible social media content.

  12. Asynchronous Free-Space Optical CDMA Communications System for Last-mile Access Network

    DEFF Research Database (Denmark)

    Jurado-Navas, Antonio; Raddo, Thiago R.; Sanches, Anderson L.

    2016-01-01

    We propose a new hybrid asynchronous OCDMA-FSO communications system for access network solutions. New ABER expressions are derived under gamma-gamma scintillation channels, where all users can surprisingly achieve error-free transmissions when FEC is employed....

  13. ABCDecision: A Simulation Platform for Access Selection Algorithms in Heterogeneous Wireless Networks

    Directory of Open Access Journals (Sweden)

    Guy Pujolle

    2010-01-01

    Full Text Available We present a simulation platform for access selection algorithms in heterogeneous wireless networks, called “ABCDecision”. The simulator implements the different parts of an Always Best Connected (ABC system, including Access Technology Selector (ATS, Radio Access Networks (RANs, and users. After describing the architecture of the simulator, we show an overview of the existing decision algorithms for access selection. Then we propose a new selection algorithm in heterogeneous networks and we run a set of simulations to evaluate the performance of the proposed algorithm in comparison with the existing ones. The performance results, in terms of the occupancy rate, show that our algorithm achieves a load balancing distribution between networks by taking into consideration the capacities of the available cells.

  14. Medium Access Control for Wireless Sensor Networks based on Impulse Radio Ultra Wideband

    OpenAIRE

    Berthe, Abdoulaye; Lecointre, Aubin; Dragomirescu, Daniela; Plana, Robert

    2010-01-01

    This paper describes a detailed performance evaluation of distributed Medium Access Control (MAC) protocols for Wireless Sensor Networks based on Impulse Radio Ultra Wideband (IR-UWB) Physical layer (PHY). Two main classes of Medium Access Control protocol have been considered: Slotted and UnSlotted with reliability. The reliability is based on Automatic Repeat ReQuest (ARQ). The performance evaluation is performed using a complete Wireless Sensor Networks (WSN) simulator built on the Global ...

  15. System Architecture and Key Technologies for 5G Heterogeneous Cloud Radio Access Networks

    OpenAIRE

    Peng, Mugen; Li, Yong; Zhao, Zhongyuan; Wang, Chonggang

    2014-01-01

    Compared with the fourth generation (4G) cellular systems, the fifth generation wireless communication systems (5G) are anticipated to provide spectral and energy efficiency growth by a factor of at least 10, and the area throughput growth by a factor of at least 25. To achieve these goals, a heterogeneous cloud radio access network (H-CRAN) is presented in this article as the advanced wireless access network paradigm, where cloud computing is used to fulfill the centralized large-scale coope...

  16. Strategies of Legitimacy Through Social Media: The Networked Strategy

    DEFF Research Database (Denmark)

    Castelló, Itziar; Etter, Michael; Nielsen, Finn Årup

    2016-01-01

    How can corporations develop legitimacy when coping with stakeholders who have multiple, often conflicting sustainable development (SD) agendas? We address this question by conducting an in-depth longitudinal case study of a corporation's stakeholder engagement in social media and propose......, legitimacy gains may increase when firms are able to reduce the control over the engagements and relate non-hierarchically with their publics. We contribute to the extant literature on political corporate social responsibility and legitimacy by providing an understanding of a new context for engagement...

  17. Open Educational Social Media Content Groups and Networks within the Arts, Design & Media Education

    OpenAIRE

    Atkinson, Sarah Anne; Follows, Chris

    2012-01-01

    This paper presents two case study perspectives of the role of open technologies in encouraging sharing and reuse of open content from SCORE fellows Sarah Atkinson and Chris Follows. Virtual Learning Environments (VLEs) and Institutional repositories are rarely built to support social media content communities, as a result many learning and teaching materials are being independently dispersed across the web using more familiar and everyday user friendly web 2.0 environments. Good quality lear...

  18. Enabling multimode wireless access networks using remote radio heads

    DEFF Research Database (Denmark)

    Kardaras, Georgios; Soler, José; Dittmann, Lars

    2012-01-01

    The deployment of 4G networks is spreading rapidly providing mobile broadband services to the public. 4G technologies are designed to overlay existing 3G networks enabling reusability of several network components. In this way, the coexistence of 3G/4G standards is facilitated. This paper describes...... and management plane. Switching between wireless standards becomes easily feasible through firmware upgrading. Finally, real-time configuration of radio functionalities, such as transmit power, receiver gain, carrier frequency, channel bandwidth and others result in a modular software defined radio platform....... © 2012 ICST Institute for Computer Science, Social Informatics and Telecommunications Engineering....

  19. Impact of pore size variability and network coupling on electrokinetic transport in porous media

    Science.gov (United States)

    Alizadeh, Shima; Bazant, Martin Z.; Mani, Ali

    2016-11-01

    We have developed and validated an efficient and robust computational model to study the coupled fluid and ion transport through electrokinetic porous media, which are exposed to external gradients of pressure, electric potential, and concentration. In our approach a porous media is modeled as a network of many pores through which the transport is described by the coupled Poisson-Nernst-Planck-Stokes equations. When the pore sizes are random, the interactions between various modes of transport may provoke complexities such as concentration polarization shocks and internal flow circulations. These phenomena impact mixing and transport in various systems including deionization and filtration systems, supercapacitors, and lab-on-a-chip devices. In this work, we present simulations of massive networks of pores and we demonstrate the impact of pore size variation, and pore-pore coupling on the overall electrokinetic transport in porous media.

  20. A Review Paper On Exploring Text Link And Spacial-Temporal Information In Social Media Networks

    Directory of Open Access Journals (Sweden)

    Dr. Mamta Madan

    2015-03-01

    Full Text Available ABSTRACT The objective of this paper is to have a literature review on the various methods to mine the knowledge from the social media by taking advantage of embedded heterogeneous information. Specifically we are trying to review different types of mining framework which provides us useful information from these networks that have heterogeneous data types including text spacial-temporal and data association LINK information. Firstly we will discuss the link mining to study the link structure with respect to Social Media SM. Secondly we summarize the various text mining models thirdly we shall review spacial as well the temporal models to extract or detect the frequent related topics from SM. Fourthly we will try to figure out few improvised models that take advantage of the link textual temporal and spacial information which motivates to discover progressive principles and fresh methodologies for DM Data Mining in social media networks SMNs.

  1. Social/Electronic Media Use of Children and Adolescents Who Attend the Pediatric Weight Management Programs of the COMPASS Network.

    Science.gov (United States)

    Siegel, Robert; Fals, Angela; Mirza, Nazrat; Datto, George; Stratbucker, William; Ievers-Landis, Carolyn E; Christison, Amy; Wang, Yu; Woolford, Susan J

    2015-10-01

    Obesity is a major healthcare problem in youth and their social/electronic media (SEM) use has been described as a risk factor. Though much is known about the newer technologies youth use to communicate, little is known about what is used by those in weight management programs. The aim of this study was to determine what types of SEM, including sedentary and active video games, youth in weight management programs use and which they prefer for communicating with healthcare providers. This was a multisite study using a 24-question online SurveyMonkey® questionnaire. Youth, 12-17 years old, attending pediatric weight management programs at seven participating centers in the Childhood Obesity Multi Program Analysis and Study System network were eligible. There were 292 responders with a mean age of 14.2 years. Fifty-four percent were female, 36% Caucasian, 35% African American, and 33% were Hispanic. Ninety-four percent had access to a computer, 71% had Internet access, and 63% had smartphones. Whereas 87% had at least one gaming system at home, 50% reported they never played sedentary video games (71% of females vs. 25% males; p social media (6%). Face-to-face communication with healthcare providers is the preferred method for youth in pediatric weight management programs. They self-reported video game use less than previously described.

  2. Achieving College Access Goals: The Relevance of New Media in Reaching First-Generation and Low-Income Teens

    Science.gov (United States)

    Krywosa, Jessica

    2008-01-01

    With so much interest around the use of new media, many people concerned with improving college access are striving to master this emerging set of resources in order to better reach students, who without encouragement, are unlikely to pursue higher education. But, how much do individuals understand about the way low-income, first-generation, and…

  3. Community access networks: how to connect the next billion to the ...

    International Development Research Centre (IDRC) Digital Library (Canada)

    Community access networks: how to connect the next billion to the Internet. Despite recent progress with mobile technology diffusion, more than four billion people worldwide are unconnected and have limited access to global communication infrastructure. The cost of implementing connectivity infrastructure in underserved ...

  4. An Ounce of Prevention: Technologists Use Network-Access Control to Protect System Resources, Students

    Science.gov (United States)

    Bolch, Matt

    2009-01-01

    Whether for an entire district, a single campus, or one classroom, allowing authorized access to a computer network can be fraught with challenges. The login process should be fairly seamless to approved users, giving them speedy access to approved Web sites, databases, and other sources of information. It also should be tough on unauthorized…

  5. The Cybermobile: A Gateway for Public Access to Network-Based Information.

    Science.gov (United States)

    Drumm, John E.; Groom, Frank M.

    1997-01-01

    Though the bookmobile has fallen on hard times, the cybermobile, a technology platform combining personal computing, CD-ROMs, fiber network, and wireless access to the Internet, may be the next step in mobile library services. Discusses standard vehicle, computer hardware, software, wireless access, and alliances with users, vendors, and community…

  6. An Efficient Medium Access Control Strategy for High Speed WDM Multiaccess Networks

    NARCIS (Netherlands)

    Laarhuis, Jan H.; Laarhuis, Jan; Koonen, A.M.J.

    1993-01-01

    A medium access control (MAC) strategy that accounts for the limited tunability of present-day lasers and filters and yet supports a large total number of wavelengths in the network is proposed. Full interconnectivity, contention-free access and a high value of concurrency are achieved by dividing

  7. Transport capacity of wireless networks: benefits from multi-access computation coding

    NARCIS (Netherlands)

    Goseling, Jasper; Gastpar, Michael; Weber, Jos H.

    2009-01-01

    We consider the effect on the transport capacity of wireless networks of different physical layer coding mechanisms. We compare the performance of traditional channel coding techniques, turning the wireless network in reliable point-to-point channels, with multi-access computation coding, in which

  8. The Changing Role of Community Networks in Providing Citizen Access to the Internet.

    Science.gov (United States)

    Keenan, Thomas P.; Trotter, David Mitchell

    1999-01-01

    Examines the changing role of community network associations or freenets in providing Internet access by examining the case of the Calgary Community Network Association (CCNA) in Alberta, Canada. Discusses the withdrawal of states from the telecommunications field, priorities of the Canadian government, and the role of the private sector.…

  9. mCRAN: A radio access network architecture for 5G indoor ccommunications

    NARCIS (Netherlands)

    Chandra, Kishor; Cao, Zizheng; Bruintjes, Tom; Prasad, R.V.; Karagiannis, Georgios; Tangdiongga, E.; van den Boom, H.P.A.; Kokkeler, Andre B.J.

    2015-01-01

    Millimeter wave (mmWave) communication is being seen as a disruptive technology for 5G era. In particular, 60GHz frequency band has emerged as a promising candidate for multi-Gbps connectivity in indoor and hotspot areas. In terms of network architecture, cloud radio access network (CRAN) has

  10. Hybrid InP-SiGe photoreceiver for the access network

    NARCIS (Netherlands)

    Urban, P.J.; Leijtens, X.J.M.; Smalbrugge, E.; Vries, T. de; Noetzel, R.; Oei, Y.S.; Xu, L.; Heijningen, M. van; Bent, G. van der; Waardt, H. de; Smit, M.K.

    2008-01-01

    In this paper, we present a low cost and polarization independent photoreceiver which is part of the optical network unit (ONU) for the fiber access network. It consists of one InPphotodetector and a low cost SiGe amplifier. It operates error free with 223 − 1 PRBS word length at 1.25 Gbit/s with

  11. Converged wireline and wireless signal distribution in optical fiber access networks

    DEFF Research Database (Denmark)

    Prince, Kamau

    This thesis presents results obtained during the course of my doctoral studies into the transport of fixed and wireless signaling over a converged otpical access infrastructure. In the formulation, development and assessment of a converged paradigma for multiple-services delivery via optical access...... networking infrastructure, I have demonstrated increased functionalities with existing optical technologies and commercially available optoelectronic devices. I have developed novel systems for extending the range of optical access systems, and have demonstrated the repurposing of standard digital devices...

  12. Youth access, creation, and content of smokeless tobacco ("dip") videos in social media.

    Science.gov (United States)

    Seidenberg, Andrew B; Rodgers, Elizabeth J; Rees, Vaughan W; Connolly, Gregory N

    2012-04-01

    Smokeless tobacco (SLT) use among white adolescent males has increased in recent years, and prevalence of SLT use among adolescent males exceeds that for smoking in several U.S. states. Recent reports have described the presence of cigarette-related content on social media Web sites popular among youth; however, little has been reported on SLT content. The YouTube video search engine was searched for the popular SLT brand Skoal, and the first 50 search results were downloaded. Video statistics data were collected for and content analysis was performed on all videos featuring smokeless use (82%). Access to SLT YouTube videos by youth was also determined by assessing whether YouTube permits youth viewing and creation of SLT videos. Mean number of views for videos analyzed was 15,422, and the most watched video had 124,276 views. Descriptions of SLT flavor/smell and social references/interactions were found in 48.8% and 63.4% of videos, respectively. By contrast, references to drug (nicotine) effects (12.2%) and public health messaging (9.8%) were less common. None of the SLT videos in the sample had restrictions that would block youth viewing. In addition, evidence of self-identified youth creating SLT videos was found for 13% of unique users in the sample. YouTube does not restrict youth from creating or viewing "dip videos." Proactive efforts are needed to ensure that YouTube and other online media do not become influential vehicles for tobacco promotion to youth. Copyright © 2012 Society for Adolescent Health and Medicine. Published by Elsevier Inc. All rights reserved.

  13. Social Media Tools for Teaching and Learning

    Science.gov (United States)

    Wagner, Ronald

    2011-01-01

    According to Wikipedia, "social media is the media designed to be disseminated through social interaction, created using highly accessible scalable techniques. Social media is the use of web-based and mobile technologies to turn communication into interactive dialogue." Social networks, such as Facebook and Twitter, contain millions of members who…

  14. Navigating the massive world of reddit: using backbone networks to map user interests in social media

    Directory of Open Access Journals (Sweden)

    Randal S. Olson

    2015-05-01

    Full Text Available In the massive online worlds of social media, users frequently rely on organizing themselves around specific topics of interest to find and engage with like-minded people. However, navigating these massive worlds and finding topics of specific interest often proves difficult because the worlds are mostly organized haphazardly, leaving users to find relevant interests by word of mouth or using a basic search feature. Here, we report on a method using the backbone of a network to create a map of the primary topics of interest in any social network. To demonstrate the method, we build an interest map for the social news web site reddit and show how such a map could be used to navigate a social media world. Moreover, we analyze the network properties of the reddit social network and find that it has a scale-free, small-world, and modular community structure, much like other online social networks such as Facebook and Twitter. We suggest that the integration of interest maps into popular social media platforms will assist users in organizing themselves into more specific interest groups, which will help alleviate the overcrowding effect often observed in large online communities.

  15. Making the Most out of Direct-Access Network Attached Storage

    OpenAIRE

    Fedorova, Alexandra; Magoutis, Kostas; Addetia, Salimah; Seltzer, Margo

    2003-01-01

    The performance of high-speed network-attached storage applications is often limited by end-system overhead, caused primarily by memory copying and network protocol processing. In this paper, we examine alternative strategies for reducing overhead in such systems. We consider optimizations to remote procedure call (RPC)-based data transfer using either remote direct memory access (RDMA) or network interface support for pre-posting of application receive buffers. We demonstrate that b...

  16. Decision dynamics in complex networks subject to mass media and social contact transmission mechanisms

    CERN Document Server

    Lucatero, Carlos Rodríguez; Jaquez, Roberto Bernal; Schaum, Alexander

    2012-01-01

    The dynamics of decisions in complex networks is studied within a Markov process framework using numerical simulations combined with mathematical insight into the process mechanisms. A mathematical discrete-time model is derived based on a set of basic assumptions on the convincing mechanisms associated to two opinions. The model is analyzed with respect to multiplicity of critical points, illustrating in this way the main behavior to be expected in the network. Particular interest is focussed on the effect of social network and exogenous mass media-based influences on the decision behavior. A set of numerical simulation results is provided illustrating how these mechanisms impact the final decision results. The analysis reveals (i) the presence of fixed-point multiplicity (with a maximum of four different fixed points), multistability, and sensitivity with respect to process parameters, and (ii) that mass media have a strong impact on the decision behavior.

  17. Multiple access protocol for supporting multimedia services in wireless ATM networks

    DEFF Research Database (Denmark)

    Liu, Hong; Dittmann, Lars; Gliese, Ulrik Bo

    1999-01-01

    The furture broadband wireless asynchronous transfer mode (ATM) networks must provide seamless extension of multimedia services from the wireline ATM networks. This requires an effecient wireless access protocol to fulfill varying Quality-og-Service (QoS) requirements for multimedia applications....... In this paper, we propose a multiple access protocol using centralized and distributed channel access control techniques to provide QoS guarantees for multimedia services by taking advantage of the characteristics of different kinds of ATM traffics. Multimedia traffic, including constant bit rate (CBR...

  18. Reconfigurable radio access unit to dynamically distribute W-band signals in 5G wireless access networks

    DEFF Research Database (Denmark)

    Rodríguez Páez, Juan Sebastián; Rommel, Simon; Vegas Olmos, Juan José

    2017-01-01

    In this paper a new type of radio access unit is proposed and demonstrated. This unit is composed only of the reduced amount of components (compared to conventional unit designs) to optically generate wireless signals on the W-band (75–110 GHz) in combination with a switching system. The proposed...... system not only achieves BER values below the FEC limit, but gives an extra level of flexibility to the network by easing the redirection of the signal to different antennas....

  19. Establishing a Social Media Presence and Network for the Pennsylvania Earth Science Teachers Association (PAESTA)

    Science.gov (United States)

    Guertin, L. A.; Merkel, C.

    2011-12-01

    as a way to build participation and membership in the online PAESTA community. Part of the approach guiding the developing of the virtual community was to provide a number of ways for teachers to access PAESTA content. We needed to find ways to establish a presence in venues where our users regularly go to find information rather than expecting them to visit our website. This includes experiments with a variety of social networking platforms including Facebook and Twitter. We also make use of sites that allow users to collect and share information such as bookmarks (Diigo), citations (Mendeley), and reading lists (Goodreads). Such sites allow us to reach new audiences with an affinity for the content that we are producing who may not otherwise find us. The tension in this approach is in maintaining information and a consistent presence across a variety of platforms. It is too early to tell which social media tools and strategies will be the most effective in creating a sense of community and interactivity among PAESTA members. Monitoring usage statistics and patterns across platforms should assist us in identifying which social media tool(s) will be most effective to continue with the mission of PAESTA.

  20. Improved Data Transmission Scheme of Network Coding Based on Access Point Optimization in VANET

    Directory of Open Access Journals (Sweden)

    Zhe Yang

    2014-01-01

    Full Text Available VANET is a hot spot of intelligent transportation researches. For vehicle users, the file sharing and content distribution through roadside access points (AP as well as the vehicular ad hoc networks (VANET have been an important complement to that cellular network. So the AP deployment is one of the key issues to improve the communication performance of VANET. In this paper, an access point optimization method is proposed based on particle swarm optimization algorithm. The transmission performances of the routing protocol with random linear network coding before and after the access point optimization are analyzed. The simulation results show the optimization model greatly affects the VANET transmission performances based on network coding, and it can enhance the delivery rate by 25% and 14% and reduce the average delay of transmission by 38% and 33%.

  1. African Copyright and Access to Knowledge Network (ACA2K ...

    International Development Research Centre (IDRC) Digital Library (Canada)

    Africa is a net importer of intellectual property covered by copyright rules. The African Comparative Copyright Review (ACCR) believes that a stringent copyright climate could limit access to knowledge goods and thereby hinder the emergence of local innovation and learning. This project will allow the ACCR to bring ...

  2. African Copyright and Access to Knowledge Network (ACA2K ...

    International Development Research Centre (IDRC) Digital Library (Canada)

    Legislative review : review of IPR Act and regulations : Intellectual Property Rights from Publically Financed Research and Development Act, Act No. 51 of 2008, Republic of South Africa. Download PDF. Journal articles. Copyright and education : lessons on African copyright and access to knowledge. Download PDF ...

  3. Repeated exposure to media violence is associated with diminished response in an inhibitory frontolimbic network.

    Directory of Open Access Journals (Sweden)

    Christopher R Kelly

    Full Text Available BACKGROUND: Media depictions of violence, although often claimed to induce viewer aggression, have not been shown to affect the cortical networks that regulate behavior. METHODOLOGY/PRINCIPAL FINDINGS: Using functional magnetic resonance imaging (fMRI, we found that repeated exposure to violent media, but not to other equally arousing media, led to both diminished response in right lateral orbitofrontal cortex (right ltOFC and a decrease in right ltOFC-amygdala interaction. Reduced function in this network has been previously associated with decreased control over a variety of behaviors, including reactive aggression. Indeed, we found reduced right ltOFC responses to be characteristic of those subjects that reported greater tendencies toward reactive aggression. Furthermore, the violence-induced reduction in right ltOFC response coincided with increased throughput to behavior planning regions. CONCLUSIONS: These novel findings establish that even short-term exposure to violent media can result in diminished responsiveness of a network associated with behaviors such as reactive aggression.

  4. The decision to access patient information from a social media site: what would you do?

    Science.gov (United States)

    Jent, Jason F; Eaton, Cyd K; Merrick, Melissa T; Englebert, Nicole E; Dandes, Susan K; Chapman, Ana V; Hershorin, Eugene R

    2011-10-01

    The current study examined the prevalence with which healthcare providers use a social media site (SMS) account (e.g., Facebook), the extent to which they use SMSs in clinical practice, and their decision-making process after accessing patient information from an SMS. Pediatric faculty and trainees from a medical school campus were provided a SMS history form and seven fictional SMS adolescent profile vignettes that depicted concerning information. Participants were instructed to rate their personal use and beliefs about SMSs and to report how they would respond if they obtained concerning information about an adolescent patient from their public SMS profile. Healthcare providers generally believed it not to be an invasion of privacy to conduct an Internet/SMS search of someone they know. A small percentage of trainees reported a personal history of conducting an Internet search (18%) or an SMS search (14%) for a patient. However, no faculty endorsed a history of conducting searches for patients. Faculty and trainees also differed in how they would respond to concerning SMS adolescent profile information. The findings that trainees are conducting Internet/SMS searches of patients and that faculty and trainees differ in how they would respond to concerning profile information suggest the need for specific guidelines regarding the role of SMSs in clinical practice. Practice, policy, and training implications are discussed. Copyright © 2011 Society for Adolescent Health and Medicine. Published by Elsevier Inc. All rights reserved.

  5. Calcium-decorated carbyne networks as hydrogen storage media.

    Science.gov (United States)

    Sorokin, Pavel B; Lee, Hoonkyung; Antipina, Lyubov Yu; Singh, Abhishek K; Yakobson, Boris I

    2011-07-13

    Among the carbon allotropes, carbyne chains appear outstandingly accessible for sorption and very light. Hydrogen adsorption on calcium-decorated carbyne chain was studied using ab initio density functional calculations. The estimation of surface area of carbyne gives the value four times larger than that of graphene, which makes carbyne attractive as a storage scaffold medium. Furthermore, calculations show that a Ca-decorated carbyne can adsorb up to 6 H(2) molecules per Ca atom with a binding energy of ∼0.2 eV, desirable for reversible storage, and the hydrogen storage capacity can exceed ∼8 wt %. Unlike recently reported transition metal-decorated carbon nanostructures, which suffer from the metal clustering diminishing the storage capacity, the clustering of Ca atoms on carbyne is energetically unfavorable. Thermodynamics of adsorption of H(2) molecules on the Ca atom was also investigated using equilibrium grand partition function.

  6. Virtual Community, social network and media environment of Canary Isands regional digital newspapers

    Directory of Open Access Journals (Sweden)

    Dr. Francisco Manuel Mateos Rodríguez

    2008-01-01

    Full Text Available The impact of the new communication and information technologies has favoured the creation of multiple local newspaper websites in the Canary Islands, thus making the regional press emerge as an alternative on the rise. This tendency affects significantly both traditional and new editions of the different regional and local newspapers from the Canaries and motivates a different distribution, positioning and development within the local media environment in which these media share a novel dimension of communication with a specific virtual community and social network within the World Wide Web.

  7. Improving Feature Representation Based on a Neural Network for Author Profiling in Social Media Texts.

    Science.gov (United States)

    Gómez-Adorno, Helena; Markov, Ilia; Sidorov, Grigori; Posadas-Durán, Juan-Pablo; Sanchez-Perez, Miguel A; Chanona-Hernandez, Liliana

    2016-01-01

    We introduce a lexical resource for preprocessing social media data. We show that a neural network-based feature representation is enhanced by using this resource. We conducted experiments on the PAN 2015 and PAN 2016 author profiling corpora and obtained better results when performing the data preprocessing using the developed lexical resource. The resource includes dictionaries of slang words, contractions, abbreviations, and emoticons commonly used in social media. Each of the dictionaries was built for the English, Spanish, Dutch, and Italian languages. The resource is freely available.

  8. Social Sensor Analytics: Making Sense of Network Models in Social Media

    Energy Technology Data Exchange (ETDEWEB)

    Dowling, Chase P.; Harrison, Joshua J.; Sathanur, Arun V.; Sego, Landon H.; Corley, Courtney D.

    2015-07-27

    Social networks can be thought of as noisy sensor networks mapping real world information to the web. Owing to the extensive body of literature in sensor network analysis, this work sought to apply several novel and traditional methods in sensor network analysis for the purposes of efficiently interrogating social media data streams from raw data. We carefully revisit our definition of a social media signal from previous work both in terms of time-varying features within the data and the networked nature of the medium. Further, we detail our analysis of global patterns in Twitter over the months of November 2013 and June 2014, detect and categorize events, and illustrate how these analyses can be used to inform graph-based models of Twitter, namely using a recent network influence model called PhySense: similar to PageRank but tuned to behavioral analysis by leveraging a sociologically inspired probabilistic model. We ultimately identify forms of information dissemination via analysis of time series and dynamic graph spectra and corroborate these findings through manual investigation of the data as a requisite step in modeling the diffusion process with PhySense. We hope to sufficiently characterize global behavior in a medium such as Twitter as a means of learning global model parameters one may use to predict or simulate behavior on a large scale. We have made our time series and dynamic graph analytical code available via a GitHub repository https://github.com/cpatdowling/salsa and our data are available upon request.

  9. PIMS Data Storage, Access, and Neural Network Processing

    Science.gov (United States)

    McPherson, Kevin M.; Moskowitz, Milton E.

    1998-01-01

    The Principal Investigator Microgravity Services (PIMS) project at NASA's Lewis Research Center has supported microgravity science Principal Investigator's (PIs) by processing, analyzing, and storing the acceleration environment data recorded on the NASA Space Shuttles and the Russian Mir space station. The acceleration data recorded in support of the microgravity science investigated on these platforms has been generated in discrete blocks totaling approximately 48 gigabytes for the Orbiter missions and 50 gigabytes for the Mir increments. Based on the anticipated volume of acceleration data resulting from continuous or nearly continuous operations, the International Space Station (ISS) presents a unique set of challenges regarding the storage of and access to microgravity acceleration environment data. This paper presents potential microgravity environment data storage, access, and analysis concepts for the ISS era.

  10. Responses to a self-presented suicide attempt in social media: a social network analysis.

    Science.gov (United States)

    Fu, King-Wa; Cheng, Qijin; Wong, Paul W C; Yip, Paul S F

    2013-01-01

    The self-presentation of suicidal acts in social media has become a public health concern. This article centers on a Chinese microblogger who posted a wrist-cutting picture that was widely circulated in Chinese social media in 2011. This exploratory study examines written reactions of a group of Chinese microbloggers exposed to the post containing a self-harming message and photo. In addition, we investigate the pattern of information diffusion via a social network. We systematically collected and analyzed 5,971 generated microblogs and the network of information diffusion. We found that a significant portion of written responses (36.6%) could help vulnerable netizens by providing peer-support and calls for help. These responses were reposted and diffused via an online social network with markedly more clusters of users--and at a faster pace-- than a set of randomly generated networks. We conclude that social media can be a double-edged sword: While it may contagiously affect others by spreading suicidal thoughts and acts, it may also play a positive role by assisting people at risk for suicide, providing rescue or support. More research is needed to learn how suicidally vulnerable people interact with online suicide information, and how we can effectively intervene.

  11. Opportunistic Access in Frequency Hopping Cognitive Radio Networks

    Science.gov (United States)

    2014-03-27

    frequency hopping radio to mitigate the interference caused by other transmitters in a contentious environment such as the unlicensed 2.4 GHz region...Avionics Circle WPAFB, OH 45433 vasu.chakravarthy@us.af.mil 937- 528 -8269 AFRL/RYWE 12. DISTRIBUTION / AVAILABILITY STATEMENT DISTRIBUTION STATEMENT A...unlicensed 2.4 GHz region. Additionally, this work demonstrates how dynamic spectrum access techniques can be used not only to prevent interfering with

  12. Admission Control and Interference Management in Dynamic Spectrum Access Networks

    Directory of Open Access Journals (Sweden)

    Jorge Martinez-Bauset

    2010-01-01

    Full Text Available We study two important aspects to make dynamic spectrum access work in practice: the admission policy of secondary users (SUs to achieve a certain degree of quality of service and the management of the interference caused by SUs to primary users (PUs. In order to limit the forced termination probability of SUs, we evaluate the Fractional Guard Channel reservation scheme to give priority to spectrum handovers over new arrivals. We show that, contrary to what has been proposed, the throughput of SUs cannot be maximized by configuring the reservation parameter. We also study the interference caused by SUs to PUs. We propose and evaluate different mechanisms to reduce the interference, which are based on simple spectrum access algorithms for both PUs and SUs and channel repacking algorithms for SUs. Numerical results show that the reduction can be of one order of magnitude or more with respect to the random access case. Finally, we propose an adaptive admission control scheme that is able to limit simultaneously the forced termination probability of SUs and what we define as the probability of interference. Our scheme does not require any configuration parameters beyond the probability objectives. Besides, it is simple to implement and it can operate with any arrival process and distribution of the session duration.

  13. Reconstruction of three-dimensional porous media using generative adversarial neural networks

    Science.gov (United States)

    Mosser, Lukas; Dubrule, Olivier; Blunt, Martin J.

    2017-10-01

    To evaluate the variability of multiphase flow properties of porous media at the pore scale, it is necessary to acquire a number of representative samples of the void-solid structure. While modern x-ray computer tomography has made it possible to extract three-dimensional images of the pore space, assessment of the variability in the inherent material properties is often experimentally not feasible. We present a method to reconstruct the solid-void structure of porous media by applying a generative neural network that allows an implicit description of the probability distribution represented by three-dimensional image data sets. We show, by using an adversarial learning approach for neural networks, that this method of unsupervised learning is able to generate representative samples of porous media that honor their statistics. We successfully compare measures of pore morphology, such as the Euler characteristic, two-point statistics, and directional single-phase permeability of synthetic realizations with the calculated properties of a bead pack, Berea sandstone, and Ketton limestone. Results show that generative adversarial networks can be used to reconstruct high-resolution three-dimensional images of porous media at different scales that are representative of the morphology of the images used to train the neural network. The fully convolutional nature of the trained neural network allows the generation of large samples while maintaining computational efficiency. Compared to classical stochastic methods of image reconstruction, the implicit representation of the learned data distribution can be stored and reused to generate multiple realizations of the pore structure very rapidly.

  14. Market opening and third party access in district heating networks

    Energy Technology Data Exchange (ETDEWEB)

    Soederholm, Patrik; Waarell, Linda [Luleaa University of Technology, Department of Business Administration and Social Sciences, Economics Unit, SE-971 87 Luleaa (Sweden)

    2011-02-15

    The purpose of this paper is to analyse the possible effects of introducing TPA in district heating networks by identifying and scrutinizing a number of possible scenarios for increased competition. The analysis builds on a theoretical discussion of economic efficiency in district heating operations, and the possible impacts on consumer prices of a market opening. An important conclusion is that regulated TPA may have small positive effects on competition, and at the same time it can have a negative impact on the possibility to run the integrated district heating operations in a cost-effective manner. This conclusion stems in part from the observation that most district heating networks are local in scope. Moreover, district heating operations are highly interdependent in, for instance, that the level of the return temperature of the water will affect the efficiency of combined heat and power plants. For these reasons, the introduction of the so-called single-buyer model or, perhaps even more preferable, an extended and more transparent producer market could represent more efficient market designs. Moreover, in networks with clear natural monopoly characteristics an ex ante price regulation must be considered. (author)

  15. On the development of online cities and neighborhoods: an exploration of cumulative and segmentive network effects in social media

    NARCIS (Netherlands)

    Maris, I.; Huizinga, A; Bouman, W.; Tuunainen, V.K.; Rossi, M.; Nandhakumar, J.

    2011-01-01

    This paper outlines a research in progress set to study network effects in social media. The focus is on outlining the theoretical framework in which this study is embedded. The concepts of cumulative network effects and segmentive network effects are introduced to explain the processes by which

  16. Using LinkedIn in the Marketing Classroom: Exploratory Insights and Recommendations for Teaching Social Media/Networking

    Science.gov (United States)

    McCorkle, Denny E.; McCorkle, Yuhua Li

    2012-01-01

    With the rapid growth of social networking and media comes their consideration for use in the marketing classroom. Social networking skills are becoming essential for personal branding (e.g., networking, self-marketing) and corporate/product branding (e.g., marketing communication). This paper addresses the use of LinkedIn (i.e., an online…

  17. Deployment of a Testbed in a Brazilian Research Network using IPv6 and Optical Access Technologies

    Science.gov (United States)

    Martins, Luciano; Ferramola Pozzuto, João; Olimpio Tognolli, João; Chaves, Niudomar Siqueira De A.; Reggiani, Atilio Eduardo; Hortêncio, Claudio Antonio

    2012-04-01

    This article presents the implementation of a testbed and the experimental results obtained with it on the Brazilian Experimental Network of the government-sponsored "GIGA Project." The use of IPv6 integrated to current and emerging optical architectures and technologies, such as dense wavelength division multiplexing and 10-gigabit Ethernet on the core and gigabit capable passive optical network and optical distribution network on access, were tested. These protocols, architectures, and optical technologies are promising and part of a brand new worldwide technological scenario that has being fairly adopted in the networks of enterprises and providers of the world.

  18. Analysis of physical layer performance of hybrid optical-wireless access network

    Science.gov (United States)

    Shaddad, R. Q.; Mohammad, A. B.; Al-hetar, A. M.

    2011-09-01

    The hybrid optical-wireless access network (HOWAN) is a favorable architecture for next generation access network. It is an optimal combination of an optical backhaul and a wireless front-end for an efficient access network. In this paper, the HOWAN architecture is designed based on a wavelengths division multiplexing/time division multiplexing passive optical network (WDM/TDM PON) at the optical backhaul and a wireless fidelity (WiFi) technology at the wireless front-end. The HOWAN is proposed that can provide blanket coverage of broadband and flexible connection for end-users. Most of the existing works, based on performance evaluation are concerned on network layer aspects. This paper reports physical layer performance in terms of the bit error rate (BER), eye diagram, and signal-to-noise ratio (SNR) of the communication system. It accommodates 8 wavelength channels with 32 optical network unit/wireless access points (ONU/APs). It is demonstrated that downstream and upstream of 2 Gb/s can be achieved by optical backhaul for each wavelength channel along optical fiber length of 20 km and a data rate of 54 Mb/s per ONU/AP along a 50 m outdoor wireless link.

  19. Adaptive Information Access in Multiple Applications Support Wireless Sensor Network

    DEFF Research Database (Denmark)

    Tobgay, Sonam; Olsen, Rasmus Løvenstein; Prasad, Ramjee

    2012-01-01

    set of requirements. Lastly, the paper suggests a mechanism by which the information access or acquisition can be adapted as per the requirements of the application. The main parameters focused in this paper are mismatch probability [1] and power dissipation with respect to sampling rate....... specific WSN considering its resource constraints, neglecting the return-of-investment and usefulness of the system. In this paper, we bring out the WSN scenario which supports multiple applications and study the challenges that would pose in implementation as each specific application has its own specific...

  20. The Strategic Combination of Open-Access Peer-Review, Mainstream Media and Social Media to Improve Public Climate Literacy (Invited)

    Science.gov (United States)

    Cook, J.; Nuccitelli, D. A.; Jacobs, P.

    2013-12-01

    The Skeptical Science website began in 2007, with the goal of refuting climate misinformation with peer-reviewed science. It achieved this by embracing a diversity of message formats and delivery methods. Myth rebuttals are available at beginner, intermediate and advanced levels, spanning from long, technical treatments to tweetable one-liners. Content has been translated into 20 different languages and made available via the web, an iPhone app and books while adopted by third parties in textbooks, university and MOOC curricula, books, Senate testimonies and TV documentaries. While social media has been a fruitful medium, we experimented with a new model in 2013, employing the strategic combination of open-access peer-review, mainstream media outreach and social media marketing. This strategy was adopted with the release of a paper quantifying the level of scientific consensus in published climate papers, resulting in broad mainstream media attention as well as acknowledgement from key public figures such as Al Gore, the UK Minister for Energy Edward Davey and President Obama. Our approach was informed by psychological research into both the importance of scientific consensus and how to reduce the influence of misconceptions. While multiple methods of delivery are important, equally important is the construction of the messages themselves. I will examine the science of crafting compelling messages and how combination with diverse message delivery can lead to impactful outcomes.

  1. Setting Access Permission through Transitive Relationship in Web-based Social Networks

    Science.gov (United States)

    Hong, Dan; Shen, Vincent Y.

    The rising popularity of various social networking websites has created a huge problem on Internet privacy. Although it is easy to post photos, comments, opinions on some events, etc. on the Web, some of these data (such as a person’s location at a particular time, criticisms of a politician, etc.) are private and should not be accessed by unauthorized users. Although social networks facilitate sharing, the fear of sending sensitive data to a third party without knowledge or permission of the data owners discourages people from taking full advantage of some social networking applications. We exploit the existing relationships on social networks and build a ‘‘trust network’’ with transitive relationship to allow controlled data sharing so that the privacy and preferences of data owners are respected. The trust network linking private data owners, private data requesters, and intermediary users is a directed weighted graph. The permission value for each private data requester can be automatically assigned in this network based on the transitive relationship. Experiments were conducted to confirm the feasibility of constructing the trust network from existing social networks, and to assess the validity of permission value assignments in the query process. Since the data owners only need to define the access rights of their closest contacts once, this privacy scheme can make private data sharing easily manageable by social network participants.

  2. Social features of online networks: the strength of weak ties in online social media

    CERN Document Server

    Grabowicz, Przemyslaw A; Moro, Esteban; Pujol, Josep; Eguiluz, Victor M

    2011-01-01

    An increasing fraction of today social interactions occurs using online social media as communication channels. Recent worldwide events, such as the revolts in Middle East or the recent social movements in Spain, reflect their capacity to boost people coordination. Online networks display, in general, a rich internal structure where users can choose among different types and intensity of interactions. Despite of this and their growing popularity, there are still open questions regarding the social value of online relations. For example, the existence of users with thousands or millions of online friends sheds doubts on the relevance of these connections. In this work, we focus on Twitter, one of the most popular online social networks, and find that the network formed by the basic type of relations is organized in groups. The activity of the users in the network is related to the landscape determined by such groups. Twitter's distinction between different types o interactions allows us to establish a parallel...

  3. Passive Optical Access Networks: State of the Art and Future Evolution

    Directory of Open Access Journals (Sweden)

    Tommaso Muciaccia

    2014-10-01

    Full Text Available In the very last years, optical access networks are growing very rapidly, from both the network operators and the research interests points of view. Fiber To The Home (FTTH is already a reality in plenty of real contexts and there has been a further stimulus to the proposal of new solutions and the investigation of new possibilities, in order to optimize network performance and reduce capital and operational expenditure. A complete and systematic overview of passive optical access networks is presented in this paper, concerning both the hot research topics and the main operative issues about the design guidelines and the deployment of Passive Optical Networks (PON architectures, nowadays the most commonly implemented approach to realize optical fiber links in the access networks. A comparison of advantages and disadvantages of different multiplexing techniques is discussed, with specific reference to WDM-based networks, almost universally considered as the enabling technology for future proof bandwidth requirements. An exhaustive summary is also given about the-state-of-the-art of modulation and encoding techniques recently proposed by the scientific community, as well as the open challenges (such as colorless and coolerless ONUs for telecom companies and international standardization compliance.

  4. Do online social media cut through the constraints that limit the size of offline social networks?

    Science.gov (United States)

    Dunbar, R I M

    2016-01-01

    The social brain hypothesis has suggested that natural social network sizes may have a characteristic size in humans. This is determined in part by cognitive constraints and in part by the time costs of servicing relationships. Online social networking offers the potential to break through the glass ceiling imposed by at least the second of these, potentially enabling us to maintain much larger social networks. This is tested using two separate UK surveys, each randomly stratified by age, gender and regional population size. The data show that the size and range of online egocentric social networks, indexed as the number of Facebook friends, is similar to that of offline face-to-face networks. For one sample, respondents also specified the number of individuals in the inner layers of their network (formally identified as support clique and sympathy group), and these were also similar in size to those observed in offline networks. This suggests that, as originally proposed by the social brain hypothesis, there is a cognitive constraint on the size of social networks that even the communication advantages of online media are unable to overcome. In practical terms, it may reflect the fact that real (as opposed to casual) relationships require at least occasional face-to-face interaction to maintain them.

  5. Capability-based Access Control Delegation Model on the Federated IoT Network

    DEFF Research Database (Denmark)

    Anggorojati, Bayu; Mahalle, Parikshit N.; Prasad, Neeli R.

    2012-01-01

    Flexibility is an important property for general access control system and especially in the Internet of Things (IoT), which can be achieved by access or authority delegation. Delegation mechanisms in access control that have been studied until now have been intended mainly for a system that has...... no resource constraint, such as a web-based system, which is not very suitable for a highly pervasive system such as IoT. To this end, this paper presents an access delegation method with security considerations based on Capability-based Context Aware Access Control (CCAAC) model intended for federated...... machine-to-machine communication or IoT networks. The main idea of our proposed model is that the access delegation is realized by means of a capability propagation mechanism, and incorporating the context information as well as secure capability propagation under federated IoT environments. By using...

  6. A novel root-index based prioritized random access scheme for 5G cellular networks

    Directory of Open Access Journals (Sweden)

    Taehoon Kim

    2015-12-01

    Full Text Available Cellular networks will play an important role in realizing the newly emerging Internet-of-Everything (IoE. One of the challenging issues is to support the quality of service (QoS during the access phase, while accommodating a massive number of machine nodes. In this paper, we show a new paradigm of multiple access priorities in random access (RA procedure and propose a novel root-index based prioritized random access (RIPRA scheme that implicitly embeds the access priority in the root index of the RA preambles. The performance evaluation shows that the proposed RIPRA scheme can successfully support differentiated performance for different access priority levels, even though there exist a massive number of machine nodes.

  7. Network interdependency between social media and stock trading activities: Evidence from China

    Science.gov (United States)

    Lin, Shen; Ren, Da; Zhang, Wei; Zhang, Yongjie; Shen, Dehua

    2016-06-01

    The emergence of social media accelerates the research on information dissemination and its corresponding influence on trading tendency. Based on empirical study of the dynamic relationship between the ratio of re-post microblog and original microblog (RRO) and average volume per transaction (VPT), we find the following results: (1) In microblog network, stocks with high RRO are often accompanied with low statistical VPT; (2) When the discussion about one stock is quite lively in microblog network (such as the blog postings reach a summit), it does not statistically cause the fluctuations of VPT of the stock; (3) Overall speaking, RRO plays a significant role in inverting u-shaped relationship with VPT.

  8. Analyzing Social Media Networks with NodeXL Insights from a Connected World

    CERN Document Server

    Hansen, Derek; Smith, Marc A

    2010-01-01

    Businesses, entrepreneurs, individuals, and government agencies alike are looking to social network analysis (SNA) tools for insight into trends, connections, and fluctuations in social media. Microsoft's NodeXL is a free, open-source SNA plug-in for use with Excel. It provides instant graphical representation of relationships of complex networked data. But it goes further than other SNA tools -- NodeXL was developed by a multidisciplinary team of experts that bring together information studies, computer science, sociology, human-computer interaction, and over 20 years of visual analytic theor

  9. Cognitive radio networks medium access control for coexistence of wireless systems

    CERN Document Server

    Bian, Kaigui; Gao, Bo

    2014-01-01

    This book gives a comprehensive overview of the medium access control (MAC) principles in cognitive radio networks, with a specific focus on how such MAC principles enable different wireless systems to coexist in the same spectrum band and carry out spectrum sharing.  From algorithm design to the latest developments in the standards and spectrum policy, readers will benefit from leading-edge knowledge of how cognitive radio systems coexist and share spectrum resources.  Coverage includes cognitive radio rendezvous, spectrum sharing, channel allocation, coexistence in TV white space, and coexistence of heterogeneous wireless systems.   • Provides a comprehensive reference on medium access control (MAC)-related problems in the design of cognitive radio systems and networks; • Includes detailed analysis of various coexistence problems related to medium access control in cognitive radio networks; • Reveals novel techniques for addressing the challenges of coexistence protocol design at a higher level ...

  10. A Brief Survey of Media Access Control, Data Link Layer, and Protocol Technologies for Lunar Surface Communications

    Science.gov (United States)

    Wallett, Thomas M.

    2009-01-01

    This paper surveys and describes some of the existing media access control and data link layer technologies for possible application in lunar surface communications and the advanced wideband Direct Sequence Code Division Multiple Access (DSCDMA) conceptual systems utilizing phased-array technology that will evolve in the next decade. Time Domain Multiple Access (TDMA) and Code Division Multiple Access (CDMA) are standard Media Access Control (MAC) techniques that can be incorporated into lunar surface communications architectures. Another novel hybrid technique that is recently being developed for use with smart antenna technology combines the advantages of CDMA with those of TDMA. The relatively new and sundry wireless LAN data link layer protocols that are continually under development offer distinct advantages for lunar surface applications over the legacy protocols which are not wireless. Also several communication transport and routing protocols can be chosen with characteristics commensurate with smart antenna systems to provide spacecraft communications for links exhibiting high capacity on the surface of the Moon. The proper choices depend on the specific communication requirements.

  11. A Prescription for Internet Access: Appealing to Middle-Aged and Older Racial and Ethnic Minorities Through Social Network Sites to Combat Colorectal Cancer.

    Science.gov (United States)

    Lumpkins, Crystal Y; Mabachi, Natabhona; Lee, Jaehoon; Pacheco, Christina; Greiner, K Allen; Geana, Mugur

    2017-07-01

    The popularity and usage of social media networks or SNS (social networking sites) among American Internet users age 50 and over doubled between 2009 and 2010 and has steadily climbed. Part of this increased access may be the result of older adults who are living with a chronic disease and are reaching out for online support. Colorectal cancer (CRC) risk is among those concerns, particularly among middle-age and older minority populations where disparities exist. This exploratory study investigates information seeking behavior related to cancer factors (e.g. testing for colon cancer, cancer fatalism) and current social media usage among racial and ethnic minority groups (African American and Latinos) and Whites age 50 and older. The secondary data from the 2012 Health Information National Trends Survey (HINTS) was analyzed to compare these populations. Results show that African Americans and Latinos were only slightly more likely to use social network sites to seek out cancer information compared to Whites. However, Whites were more likely to use the Internet to seek health information compared to African Americans and Latinos. In this sample, Whites were also more likely to be informed by a physician about CRC testing (p social media networks, Internet sites) have increased among older Americans and can serve as critical channels for cancer information and education.

  12. Cross-layer design for radio resource allocation based on priority scheduling in OFDMA wireless access network

    Directory of Open Access Journals (Sweden)

    Chen Yen-Wen

    2011-01-01

    Full Text Available Abstract The orthogonal frequency-division multiple access (OFDMA system has the advantages of flexible subcarrier allocation and adaptive modulation with respect to channel conditions. However, transmission overhead is required in each frame to broadcast the arrangement of radio resources to all mobile stations within the coverage of the same base station. This overhead greatly affects the utilization of valuable radio resources. In this paper, a cross layer scheme is proposed to reduce the number of traffic bursts at the downlink of an OFDMA wireless access network so that the overhead of the media access protocol (MAP field can be minimized. The proposed scheme considers the priorities and the channel conditions of quality of service (QoS traffic streams to arrange for them to be sent with minimum bursts in a heuristic manner. In addition, the trade-off between the degradation of the modulation level and the reduction of traffic bursts is investigated. Simulation results show that the proposed scheme can effectively reduce the traffic bursts and, therefore, increase resource utilization.

  13. Transformation of Traditional Marketing Communications in to Paradigms of Social Media Networking

    OpenAIRE

    Nair, T. R. Gopalakrishnan; Subramaniam, Kumarashvari

    2012-01-01

    Effective Communication for marketing is a vital field in business organizations, which is used to convey the details about their products and services to the market segments and subsequently to build long lasting customer relationships. This paper focuses on an emerging component of the integrated marketing communication, ie. social media networking, as it is increasingly becoming the trend. In 21st century, the marketing communication platforms show a tendency to shift towards innovative te...

  14. Utilizing neural networks in magnetic media modeling and field computation: A review

    OpenAIRE

    Amr A. Adly; Abd-El-Hafiz, Salwa K.

    2013-01-01

    Magnetic materials are considered as crucial components for a wide range of products and devices. Usually, complexity of such materials is defined by their permeability classification and coupling extent to non-magnetic properties. Hence, development of models that could accurately simulate the complex nature of these materials becomes crucial to the multi-dimensional field-media interactions and computations. In the past few decades, artificial neural networks (ANNs) have been utilized in ma...

  15. Microarchitecture and Implementation of Networks-on-Chip with a Flexible Concept for Communication Media Sharing

    OpenAIRE

    Samman, Faizal Arya

    2010-01-01

    This thesis proposes a concept, VLSI microarchitecture and implementation of a network on-chip (NoC) supporting a flexible communication media share methodology. The concept and methodology are based on a variable dynamic local identity tag (ID-tag) management technique, where different messages can be interleaved at flit-level on the same communication channel. Each message is multiplexed and allocated to a local ID slot on the shared channel. In order to implement the concept and methodolog...

  16. Impact of green technologies in optical networks case study: green wireless optical broadband access network

    Science.gov (United States)

    Puche, William S.; Sierra, Javier E.

    2014-09-01

    This article analyzes the current state of green technologies in optical telecommunications networks, analyzing in detail the basic structure of a hybrid network (Optical-Wireless), taking into account energy consumption by proposing a mathematical model is presented to establish the optimum number of ONUs in a network.

  17. Building a multimodal network and determining individual accessibility by public transportation

    DEFF Research Database (Denmark)

    Djurhuus, Sune; Hansen, Henning Sten; Aadahl, Mette

    2016-01-01

    time thresholds. The method is used successfully to create a multimodal travel-time network model of the Capital Region of Denmark comprising bus, train, light rail, metro, and ferry as well as integrating walking or cycling to stops. Here, the individual accessibility is defined as accessibility areas......The increased availability of transit schedules from web sites or travel planners as well as more disaggregate data has led to a growing interest in creating individual public transportation accessibility measures. However, used extensively, standard GIS software does not have direct capabilities...... to integrate transit schedules into multimodal networks and measure space–time-based accessibility. This has caused authors to either simplify travel time elements or develop tools to overcome these challenges. In this paper we aim to describe and implement a method that enables integrating time-table data...

  18. A Framework Design for Load-balanced Green Access Networks supporting GSM Femtocell

    Directory of Open Access Journals (Sweden)

    Ray-Guang Cheng

    2015-02-01

    Full Text Available Reducing the energy consumption and carbon footprint emissions to improve the global climate change has become the global concern. However, CO2 generated from the current mobile devices and infrastructure has increased. Many researchers intended to develop the communication systems with low energy-consumption technologies, called the green communication. This paper proposes a framework of the load balanced green access network supporting the GSM femtocell service. By using the USRP software-defined radio device, we can build a GSM femtocell base station by software configuration. Besides, the proposed network can also extend the coverage of base stations by integrating with radio over fiber technology. With the load balancer, the proposed green access network can accomplish low power consumption, high energy efficiency, and easy to maintain. The experimental results showed that it can effectively save 24% energy consumption for the overall network and meet the quality-of-service of user when the proposed framework is applied.

  19. Performance Evaluation of 5G Millimeter-Wave Cellular Access Networks Using a Capacity-Based Network Deployment Tool

    Directory of Open Access Journals (Sweden)

    Michel Matalatala

    2017-01-01

    Full Text Available The next fifth generation (5G of wireless communication networks comes with a set of new features to satisfy the demand of data-intensive applications: millimeter-wave frequencies, massive antenna arrays, beamforming, dense cells, and so forth. In this paper, we investigate the use of beamforming techniques through various architectures and evaluate the performance of 5G wireless access networks, using a capacity-based network deployment tool. This tool is proposed and applied to a realistic area in Ghent, Belgium, to simulate realistic 5G networks that respond to the instantaneous bit rate required by the active users. The results show that, with beamforming, 5G networks require almost 15% more base stations and 4 times less power to provide more capacity to the users and the same coverage performances, in comparison with the 4G reference network. Moreover, they are 3 times more energy efficient than the 4G network and the hybrid beamforming architecture appears to be a suitable architecture for beamforming to be considered when designing a 5G cellular network.

  20. A Method for Upper Bounding Long Term Growth of Network Access Speed

    DEFF Research Database (Denmark)

    Knudsen, Thomas Phillip; Pedersen, Jens Myrup; Madsen, Ole Brun

    2004-01-01

    The development in home Internet access speed has shown an exponential development with growth rates averaging 25% per year. For resource management in network provisioning it becomes an urgent question how long such growth can continue. This paper presents a method for calculating an upper bound...... to visual content driven growth, proceeding from datarate requirements for a full virtual environment. Scenarios and approaches for reducing datarate requirements are considered and discussed. The presented figures for an upper bound on network access speed are discussed and perspectives on further research...

  1. MAC Protocols for Optimal Information Retrieval Pattern in Sensor Networks with Mobile Access

    Directory of Open Access Journals (Sweden)

    Dong Min

    2005-01-01

    Full Text Available In signal field reconstruction applications of sensor network, the locations where the measurements are retrieved from affect the reconstruction performance. In this paper, we consider the design of medium access control (MAC protocols in sensor networks with mobile access for the desirable information retrieval pattern to minimize the reconstruction distortion. Taking both performance and implementation complexity into consideration, besides the optimal centralized scheduler, we propose three decentralized MAC protocols, namely, decentralized scheduling through carrier sensing, Aloha scheduling, and adaptive Aloha scheduling. Design parameters for the proposed protocols are optimized. Finally, performance comparison among these protocols is provided via simulations.

  2. A Novel Dynamic Spectrum Access Framework Based on Reinforcement Learning for Cognitive Radio Sensor Networks.

    Science.gov (United States)

    Lin, Yun; Wang, Chao; Wang, Jiaxing; Dou, Zheng

    2016-10-12

    Cognitive radio sensor networks are one of the kinds of application where cognitive techniques can be adopted and have many potential applications, challenges and future research trends. According to the research surveys, dynamic spectrum access is an important and necessary technology for future cognitive sensor networks. Traditional methods of dynamic spectrum access are based on spectrum holes and they have some drawbacks, such as low accessibility and high interruptibility, which negatively affect the transmission performance of the sensor networks. To address this problem, in this paper a new initialization mechanism is proposed to establish a communication link and set up a sensor network without adopting spectrum holes to convey control information. Specifically, firstly a transmission channel model for analyzing the maximum accessible capacity for three different polices in a fading environment is discussed. Secondly, a hybrid spectrum access algorithm based on a reinforcement learning model is proposed for the power allocation problem of both the transmission channel and the control channel. Finally, extensive simulations have been conducted and simulation results show that this new algorithm provides a significant improvement in terms of the tradeoff between the control channel reliability and the efficiency of the transmission channel.

  3. Channel Access and Power Control for Mobile Crowdsourcing in Device-to-Device Underlaid Cellular Networks

    Directory of Open Access Journals (Sweden)

    Yue Ma

    2018-01-01

    Full Text Available With the access of a myriad of smart handheld devices in cellular networks, mobile crowdsourcing becomes increasingly popular, which can leverage omnipresent mobile devices to promote the complicated crowdsourcing tasks. Device-to-device (D2D communication is highly desired in mobile crowdsourcing when cellular communications are costly. The D2D cellular network is more preferable for mobile crowdsourcing than conventional cellular network. Therefore, this paper addresses the channel access and power control problem in the D2D underlaid cellular networks. We propose a novel semidistributed network-assisted power and a channel access control scheme for D2D user equipment (DUE pieces. It can control the interference from DUE pieces to the cellular user accurately and has low information feedback overhead. For the proposed scheme, the stochastic geometry tool is employed and analytic expressions are derived for the coverage probabilities of both the cellular link and D2D links. We analyze the impact of key system parameters on the proposed scheme. The Pareto optimal access threshold maximizing the total area spectral efficiency is obtained. Unlike the existing works, the performances of the cellular link and D2D links are both considered. Simulation results show that the proposed method can improve the total area spectral efficiency significantly compared to existing schemes.

  4. Basics of Computer Networking

    CERN Document Server

    Robertazzi, Thomas

    2012-01-01

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

  5. Predictors of Emerging Suicide Death Among Military Personnel on Social Media Networks.

    Science.gov (United States)

    Bryan, Craig J; Butner, Jonathan E; Sinclair, Sungchoon; Bryan, Anna Belle O; Hesse, Christina M; Rose, Andree E

    2017-07-28

    Suicide is a leading cause of death in the United States and is the second leading cause of death in the U.S. military. Previous research suggests that data obtained from social media networks may provide important clues for identifying at-risk individuals. To test this possibility, the social media profiles from 315 military personnel who died by suicide (n = 157) or other causes (n = 158) were coded for the presence of stressful life situations (i.e., triggers), somatic complaints or health issues (i.e., physical), maladaptive or avoidant coping strategies (i.e., behaviors), negative mood states (i.e., emotion), and/or negative cognitive appraisals (cognition). Content codes were subsequently analyzed using multilevel models from a dynamical systems perspective to identify temporal change processes characteristic of suicide death. Results identified temporal sequences unique to suicide, notably social media posts about triggers followed by more posts about cognitions, posts about cognitions followed by more posts about triggers, and posts about behaviors followed by fewer posts about cognitions. Results suggest that certain sequences in social media content may predict cause of death and provide an estimate of when a social media user is likely to die by suicide. © 2017 The American Association of Suicidology.

  6. Volume serving and media management in a networked, distributed client/server environment

    Science.gov (United States)

    Herring, Ralph H.; Tefend, Linda L.

    1993-01-01

    The E-Systems Modular Automated Storage System (EMASS) is a family of hierarchical mass storage systems providing complete storage/'file space' management. The EMASS volume server provides the flexibility to work with different clients (file servers), different platforms, and different archives with a 'mix and match' capability. The EMASS design considers all file management programs as clients of the volume server system. System storage capacities are tailored to customer needs ranging from small data centers to large central libraries serving multiple users simultaneously. All EMASS hardware is commercial off the shelf (COTS), selected to provide the performance and reliability needed in current and future mass storage solutions. All interfaces use standard commercial protocols and networks suitable to service multiple hosts. EMASS is designed to efficiently store and retrieve in excess of 10,000 terabytes of data. Current clients include CRAY's YMP Model E based Data Migration Facility (DMF), IBM's RS/6000 based Unitree, and CONVEX based EMASS File Server software. The VolSer software provides the capability to accept client or graphical user interface (GUI) commands from the operator's console and translate them to the commands needed to control any configured archive. The VolSer system offers advanced features to enhance media handling and particularly media mounting such as: automated media migration, preferred media placement, drive load leveling, registered MediaClass groupings, and drive pooling.

  7. Traffic Control Algorithm Offering Multi-Class Fairness in PON Based Access Networks

    Science.gov (United States)

    Okumura, Yasuyuki

    This letter proposes a dynamic bandwidth allocation algorithm for access networks based PON (Passive Optical Network). It considers the mixture of transport layer protocols when responding to traffic congestion at the SNI (Service Node Interface). Simulations on a mixture of TCP (Transmission Control Protocol), and UDP (User Datagram Protocol) traffic flows show that the algorithm increases the throughput of TCP, improves the fairness between the two protocols, and solves the congestion problem at the SNI.

  8. How to Cut the Electric Bill in Mobile Access Networks: A Mobile Operator's Perspective

    OpenAIRE

    Chatzimichail, Konstantinos

    2014-01-01

    One of the major challenges that mobile operators are facing is the increasing power consumption costs as a consequence of the network densication experienced in current and future mobile access networks. This power increase causes both financial and environmental concerns to operators, since both the operational expenses and the CO2 emissions are affected. This Master Thesis investigates and analyses various deployment architectures in urban and suburban areas, considering both the radio acc...

  9. Unsynchronized Energy-Efficient Medium Access Control and Routing in Wireless Sensor Networks

    Science.gov (United States)

    Hurni, Philipp

    This master thesis investigates optimizations on recently proposed fully unsynchronized power saving sensor MAC protocols. In contrast to many other sensor MAC protocols, unsynchronized sensor MAC protocols renounce on any kind of network- or cluster-wide synchronization for channel access coordination and maintenance of a common wake-sleep pattern, because in wireless sensor networks with low traffic requirements, the overhead for maintaining synchronization is likely to exceed the energy spent for the actual data traffic.

  10. ONU power saving modes in next generation optical access networks: progress, efficiency and challenges.

    Science.gov (United States)

    Dixit, Abhishek; Lannoo, Bart; Colle, Didier; Pickavet, Mario; Demeester, Piet

    2012-12-10

    The optical network unit (ONU), installed at a customer's premises, accounts for about 60% of power in current fiber-to-the-home (FTTH) networks. We propose a power consumption model for the ONU and evaluate the ONU power consumption in various next generation optical access (NGOA) architectures. Further, we study the impact of the power savings of the ONU in various low power modes such as power shedding, doze and sleep.

  11. Review of pore network modelling of porous media: Experimental characterisations, network constructions and applications to reactive transport

    Science.gov (United States)

    Xiong, Qingrong; Baychev, Todor G.; Jivkov, Andrey P.

    2016-09-01

    Pore network models have been applied widely for simulating a variety of different physical and chemical processes, including phase exchange, non-Newtonian displacement, non-Darcy flow, reactive transport and thermodynamically consistent oil layers. The realism of such modelling, i.e. the credibility of their predictions, depends to a large extent on the quality of the correspondence between the pore space of a given medium and the pore network constructed as its representation. The main experimental techniques for pore space characterisation, including direct imaging, mercury intrusion porosimetry and gas adsorption, are firstly summarised. A review of the main pore network construction techniques is then presented. Particular focus is given on how such constructions are adapted to the data from experimentally characterised pore systems. Current applications of pore network models are considered, with special emphasis on the effects of adsorption, dissolution and precipitation, as well as biomass growth, on transport coefficients. Pore network models are found to be a valuable tool for understanding and predicting meso-scale phenomena, linking single pore processes, where other techniques are more accurate, and the homogenised continuum porous media, used by engineering community.

  12. Social media in the public sector: a guide to participation, collaboration, and transparency in the networked world

    National Research Council Canada - National Science Library

    Mergel, Ines

    2013-01-01

    ..., networked governance, and information management. Comprehensive in scope, the book includes best practices, the strategic, managerial, administrative, and procedural aspects of using social media, and explains the theoretical dimensions of how...

  13. Social media in the public sector: a guide to participation, collaboration, and transparency in the networked world

    National Research Council Canada - National Science Library

    Mergel, Ines

    2013-01-01

    ..., networked governance, and information management. Comprehensive in scope, the book includes best practices, the strategic, managerial, administrative, and procedural aspects of using social media, and explains the theoretical dimensions...

  14. Media

    National Research Council Canada - National Science Library

    Emily Wexler

    2010-01-01

    .... Tradigital allows us to use online behaviour to track the effectiveness of online and offline media, not simply the correlation of TV airings with search activity, but also by employing a bevy...

  15. Efficient traffic grooming with dynamic ONU grouping for multiple-OLT-based access network

    Science.gov (United States)

    Zhang, Shizong; Gu, Rentao; Ji, Yuefeng; Wang, Hongxiang

    2015-12-01

    Fast bandwidth growth urges large-scale high-density access scenarios, where the multiple Passive Optical Networking (PON) system clustered deployment can be adopted as an appropriate solution to fulfill the huge bandwidth demands, especially for a future 5G mobile network. However, the lack of interaction between different optical line terminals (OLTs) results in part of the bandwidth resources waste. To increase the bandwidth efficiency, as well as reduce bandwidth pressure at the edge of a network, we propose a centralized flexible PON architecture based on Time- and Wavelength-Division Multiplexing PON (TWDM PON). It can provide flexible affiliation for optical network units (ONUs) and different OLTs to support access network traffic localization. Specifically, a dynamic ONU grouping algorithm (DGA) is provided to obtain the minimal OLT outbound traffic. Simulation results show that DGA obtains an average 25.23% traffic gain increment under different OLT numbers within a small ONU number situation, and the traffic gain will increase dramatically with the increment of the ONU number. As the DGA can be deployed easily as an application running above the centralized control plane, the proposed architecture can be helpful to improve the network efficiency for future traffic-intensive access scenarios.

  16. Future Scenarios for Software-Defined Metro and Access Networks and Software-Defined Photonics

    Directory of Open Access Journals (Sweden)

    Tommaso Muciaccia

    2017-01-01

    Full Text Available In recent years, architectures, devices, and components in telecommunication networks have been challenged by evolutionary and revolutionary factors which are drastically changing the traffic features. Most of these changes imply the need for major re-configurability and programmability not only in data-centers and core networks, but also in the metro-access segment. In a wide variety of contexts, this necessity has been addressed by the proposed introduction of the innovative paradigm of software-defined networks (SDNs. Several solutions inspired by the SDN model have been recently proposed also for metro and access networks, where the adoption of a new generation of software-defined reconfigurable integrated photonic devices is highly desirable. In this paper, we review the possible future application scenarios for software-defined metro and access networks and software-defined photonics (SDP, on the base of analytics, statistics, and surveys. This work describes the reasons underpinning the presented radical change of paradigm and summarizes the most significant solutions proposed in literature, with a specific emphasis to physical-layer reconfigurable networks and a focus on both architectures and devices.

  17. Service Class Resource Management For Green Wireless-Optical Broadband Access NetworksWOBAN

    Directory of Open Access Journals (Sweden)

    SRUTHY.S

    2015-08-01

    Full Text Available Abstract-Broadband access networks have become an essential part of worldwide communication systems because of the exponential growth of broadband services such as video on demand high definition TV internet protocol TV and video conferencing. Exponential growth in the volume of wireless data boosted by the growing popularity of mobile devices such as smartphone and tablets has forced the telecommunication industries to rethink the way networks are currently designed and to focus on the development of high-capacity mobile broadband networks. In response to this challenge researchers have been working toward the development of an integrated wireless optical broadband access network. Two major candidate technologies which are currently known for their high capacity as well as quality of service QoS for multimedia traffic are passive optical networks PON and fourth generation 4G wireless networks. PON is a wired access technology well known for its cost efficiency and high capacity whereas 4G is a wireless broadband access technology which has achieved broad market acceptance because of its ease of deployment ability to offer mobility and its cost efficiency. Integration of PON and 4G technologies in the form of wireless-optical broadband access networks offers advantages such as extension of networks in rural areas support for mobile broadband services and quick deployment of broadband networks. These two technologies however have different design architectures for handling broadband services that require quality of service. For example 4G networks use traffic classification for supporting different QoS demands whereas the PON architecture has no such mechanism to differentiate between types of traffic. These two technologies also differ in their power saving mechanisms. Propose a service class mapping for the integrated PON-4G network which is based on the MG1 queuing model and class-based power saving mechanism which significantly improves the

  18. Redirecting a client device from a first gateway to a second gateway for accessing a network node function

    NARCIS (Netherlands)

    Strijkers, R.J.; Norp, A.H.J.

    2014-01-01

    The present invention enables a network operator to select a gateway that provides desirable operational parameters to access a network node function in a network node requested by a client. A network service provider detects what service a client device is requesting or using and selects a gateway

  19. Inside the Digital Wild West: How School Leaders Both Access and Avoid Social Media

    Science.gov (United States)

    Corrigan, Laurie; Robertson, Lorayne

    2015-01-01

    This study examines the roles of Canadian school leaders in response to the rising phenomenon of student use of social media which impacts school climate and safety. The use of social media has resulted in more online text and image-based communication to multiple users and less face-to-face communication with single users. Adolescent…

  20. A hybrid medium access control for convergence of broadband wireless and wireline ATM networks

    DEFF Research Database (Denmark)

    Liu, Hong; Gliese, Ulrik Bo; Dittmann, Lars

    2000-01-01

    In this paper, we propose a hybrid medium access control protocol for supporting broadband integrated services in the wireless ATM networks. The integrated services include CBR, VBR and ABR traffic varying from low bit-rate to very high bit-rate. The proposed protocol is an excellent compromise...... of contention, reservation and polling access techniques based on the dynamic TDMA system. Extensive simulation results using realistic data traffic sources, show that the proposed medium access scheme may provide QoS guarantees to different ATM traffic including the realistic MPEG video traces with low cell...

  1. [Semantic Network Analysis of Online News and Social Media Text Related to Comprehensive Nursing Care Service].

    Science.gov (United States)

    Kim, Minji; Choi, Mona; Youm, Yoosik

    2017-12-01

    As comprehensive nursing care service has gradually expanded, it has become necessary to explore the various opinions about it. The purpose of this study is to explore the large amount of text data regarding comprehensive nursing care service extracted from online news and social media by applying a semantic network analysis. The web pages of the Korean Nurses Association (KNA) News, major daily newspapers, and Twitter were crawled by searching the keyword 'comprehensive nursing care service' using Python. A morphological analysis was performed using KoNLPy. Nodes on a 'comprehensive nursing care service' cluster were selected, and frequency, edge weight, and degree centrality were calculated and visualized with Gephi for the semantic network. A total of 536 news pages and 464 tweets were analyzed. In the KNA News and major daily newspapers, 'nursing workforce' and 'nursing service' were highly rated in frequency, edge weight, and degree centrality. On Twitter, the most frequent nodes were 'National Health Insurance Service' and 'comprehensive nursing care service hospital.' The nodes with the highest edge weight were 'national health insurance,' 'wards without caregiver presence,' and 'caregiving costs.' 'National Health Insurance Service' was highest in degree centrality. This study provides an example of how to use atypical big data for a nursing issue through semantic network analysis to explore diverse perspectives surrounding the nursing community through various media sources. Applying semantic network analysis to online big data to gather information regarding various nursing issues would help to explore opinions for formulating and implementing nursing policies.

  2. Optimal design of mixed-media packet-switching networks - Routing and capacity assignment

    Science.gov (United States)

    Huynh, D.; Kuo, F. F.; Kobayashi, H.

    1977-01-01

    This paper considers a mixed-media packet-switched computer communication network which consists of a low-delay terrestrial store-and-forward subnet combined with a low-cost high-bandwidth satellite subnet. We show how to route traffic via ground and/or satellite links by means of static, deterministic procedures and assign capacities to channels subject to a given linear cost such that the network average delay is minimized. Two operational schemes for this network model are investigated: one is a scheme in which the satellite channel is used as a slotted ALOHA channel; the other is a new multiaccess scheme we propose in which whenever a channel collision occurs, retransmission of the involved packets will route through ground links to their destinations. The performance of both schemes is evaluated and compared in terms of cost and average packet delay tradeoffs for some examples. The results offer guidelines for the design and optimal utilization of mixed-media networks.

  3. Measuring geographic access to health care: raster and network-based methods

    Directory of Open Access Journals (Sweden)

    Delamater Paul L

    2012-05-01

    Full Text Available Abstract Background Inequalities in geographic access to health care result from the configuration of facilities, population distribution, and the transportation infrastructure. In recent accessibility studies, the traditional distance measure (Euclidean has been replaced with more plausible measures such as travel distance or time. Both network and raster-based methods are often utilized for estimating travel time in a Geographic Information System. Therefore, exploring the differences in the underlying data models and associated methods and their impact on geographic accessibility estimates is warranted. Methods We examine the assumptions present in population-based travel time models. Conceptual and practical differences between raster and network data models are reviewed, along with methodological implications for service area estimates. Our case study investigates Limited Access Areas defined by Michigan’s Certificate of Need (CON Program. Geographic accessibility is calculated by identifying the number of people residing more than 30 minutes from an acute care hospital. Both network and raster-based methods are implemented and their results are compared. We also examine sensitivity to changes in travel speed settings and population assignment. Results In both methods, the areas identified as having limited accessibility were similar in their location, configuration, and shape. However, the number of people identified as having limited accessibility varied substantially between methods. Over all permutations, the raster-based method identified more area and people with limited accessibility. The raster-based method was more sensitive to travel speed settings, while the network-based method was more sensitive to the specific population assignment method employed in Michigan. Conclusions Differences between the underlying data models help to explain the variation in results between raster and network-based methods. Considering that the

  4. Comparison of a Ring On-Chip Network and a Code-Division Multiple-Access On-Chip Network

    OpenAIRE

    Xin Wang; Jari Nurmi

    2007-01-01

    Two network-on-chip (NoC) designs are examined and compared in this paper. One design applies a bidirectional ring connection scheme, while the other design applies a code-division multiple-access (CDMA) connection scheme. Both of the designs apply globally asynchronous locally synchronous (GALS) scheme in order to deal with the issue of transferring data in a multiple-clock-domain environment of an on-chip system. The two NoC designs are compared with each other by their network structures, ...

  5. Advance reservation access control using software-defined networking and tokens

    Energy Technology Data Exchange (ETDEWEB)

    Chung, Joaquin; Jung, Eun-Sung; Kettimuthu, Rajkumar; Rao, Nageswara S. V.; Foster, Ian T.; Clark, Russ; Owen, Henry

    2018-02-01

    Advance reservation systems allow users to reserve dedicated bandwidth connection resources from advanced high-speed networks. A common use case for such systems is data transfers in distributed science environments in which a user wants exclusive access to the reservation. However, current advance network reservation methods cannot ensure exclusive access of a network reservation to the specific flow for which the user made the reservation. We present here a novel network architecture that addresses this limitation and ensures that a reservation is used only by the intended flow. We achieve this by leveraging software-defined networking (SDN) and token-based authorization. We use SDN to orchestrate and automate the reservation of networking resources, end-to-end and across multiple administrative domains, and tokens to create a strong binding between the user or application that requested the reservation and the flows provisioned by SDN. We conducted experiments on the ESNet 100G SDN testbed, and demonstrated that our system effectively protects authorized flows from competing traffic in the network. (C) 2017 Elsevier B.V. All rights reserved.

  6. Automation in accession classification of Brazilian Capsicum germplasm through artificial neural networks

    Directory of Open Access Journals (Sweden)

    Mariane Gonçalves Ferreira

    Full Text Available ABSTRACT Germplasm classification by species requires specific knowledge on/of the culture of interest. Therefore, efforts aimed at automation of this process are necessary for the efficient management of collections. Automation of germplasm classification through artificial neural networks may be a viable and less laborious strategy. The aims of this study were to verify the classification potential of Capsicum accessions regarding/ the species based on morphological descriptors and artificial neural networks, and to establish the most important descriptors and the best network architecture for this purpose. Five hundred and sixty-four plants from 47 Brazilian Capsicum accessions were evaluated. Neural networks of multilayer perceptron type were used in order to automate the species identification through 17 morphological descriptors. Six network architectures were evaluated, and the number of neurons in the hidden layer ranged from 1 to 6. The relative importance of morphological descriptors in the classification process was established by Garson's method. Corolla color, corolla spot color, calyx annular constriction, fruit shape at pedicel attachment, and fruit color at mature stage were the most important descriptors. The network architecture with 6 neurons in the hidden layer is the most appropriate in this study. The possibility of classifying Capsicum plants regarding/ the species through artificial neural networks with 100 % accuracy was verified.

  7. Predicting social networking site use and online communication practices among adolescents: the role of Access and device ownership

    OpenAIRE

    Drew P. Cingel; Lauricella, Alexis R.; Ellen Wartella; Annie Conway

    2014-01-01

    Given adolescents' heavy social media use, this study examined a number of predictors of adolescent social media use, as well as predictors of online communication practices. Using data collected from a national sample of 467 adolescents between the ages of 13 and 17, results indicate that demographics, technology access, and technology ownership are related to social media use and communication practices. Specifically, females log onto and use more constructive com-munication practices on Fa...

  8. Predicting social networking site use and online communication practices among adolescents: the role of Access and device ownership

    OpenAIRE

    Drew P. Cingel; Lauricella, Alexis R.; Ellen Wartella; Annie Conway

    2013-01-01

    Given adolescents' heavy social media use, this study examined a number of predictors of adolescent social media use, as well as predictors of online communication practices. Using data collected from a national sample of 467 adolescents between the ages of 13 and 17, results indicate that demographics, technology access, and technology ownership are related to social media use and communication practices. Specifically, females log onto and use more constructive communication practices on Fac...

  9. QoS Provisioning Techniques for Future Fiber-Wireless (FiWi Access Networks

    Directory of Open Access Journals (Sweden)

    Martin Maier

    2010-04-01

    Full Text Available A plethora of enabling optical and wireless access-metro network technologies have been emerging that can be used to build future-proof bimodal fiber-wireless (FiWi networks. Hybrid FiWi networks aim at providing wired and wireless quad-play services over the same infrastructure simultaneously and hold great promise to mitigate the digital divide and change the way we live and work by replacing commuting with teleworking. After overviewing enabling optical and wireless network technologies and their QoS provisioning techniques, we elaborate on enabling radio-over-fiber (RoF and radio-and-fiber (R&F technologies. We describe and investigate new QoS provisioning techniques for future FiWi networks, ranging from traffic class mapping, scheduling, and resource management to advanced aggregation techniques, congestion control, and layer-2 path selection algorithms.

  10. Identifying Opinion Leaders to Promote Organ Donation on Social Media: Network Study.

    Science.gov (United States)

    Shi, Jingyuan; Salmon, Charles T

    2018-01-09

    In the recent years, social networking sites (SNSs, also called social media) have been adopted in organ donation campaigns, and recruiting opinion leaders for such campaigns has been found effective in promoting behavioral changes. The aim of this paper was to focus on the dissemination of organ donation tweets on Weibo, the Chinese equivalent of Twitter, and to examine the opinion leadership in the retweet network of popular organ donation messages using social network analysis. It also aimed to investigate how personal and social attributes contribute to a user's opinion leadership on the topic of organ donation. All messages about organ donation posted on Weibo from January 1, 2015 to December 31, 2015 were extracted using Python Web crawler. A retweet network with 505,047 nodes and 545,312 edges of the popular messages (n=206) was constructed and analyzed. The local and global opinion leaderships were measured using network metrics, and the roles of personal attributes, professional knowledge, and social positions in obtaining the opinion leadership were examined using general linear model. The findings revealed that personal attributes, professional knowledge, and social positions predicted individual's local opinion leadership in the retweet network of popular organ donation messages. Alternatively, personal attributes and social positions, but not professional knowledge, were significantly associated with global opinion leadership. The findings of this study indicate that health campaign designers may recruit peer leaders in SNS organ donation promotions to facilitate information sharing among the target audience. Users who are unverified, active, well connected, and experienced with information and communications technology (ICT) will accelerate the sharing of organ donation messages in the global environment. Medical professionals such as organ transplant surgeons who can wield a great amount of influence on their direct connections could also effectively

  11. A Low-Latency, Information-Centric Medium Access Protocol for Wireless Sensor Networks

    NARCIS (Netherlands)

    van Hoesel, L.F.W.; Havinga, Paul J.M.; Chatterjea, Supriyo

    In this paper we present a novel TDMA-based medium access control (MAC) protocol for wireless sensor networks. Unlike conventional MAC protocols which function independently of the application, we introduce an Adaptive, Information-centric and Lightweight MAC(AI-LMAC) protocol that adapts its

  12. Request-TDMA: A multiple-access protocol for wireless multimedia networks

    NARCIS (Netherlands)

    Linnenbank, G.R.J.; Havinga, Paul J.M.; Smit, Gerardus Johannes Maria; Mullender, Sape J.; Smulders, P.; van den Meerendonk, H.

    1995-01-01

    This paper describes a cellular multiple-access scheme based on TDMA for multimedia communication networks. The scheme proposes an admission control of two different multimedia application stream types: real-time and non-real-time. We do not consider interference between cells. The proposed

  13. Knowledge-Based Multiple Access Protocol in Broadband Wireless ATM Networks

    DEFF Research Database (Denmark)

    Liu, Hong; Gliese, Ulrik Bo; Dittmann, Lars

    1999-01-01

    In this paper, we propose a knowledge-based multiple access protocol for the extension of wireline ATM to wireless networks. The objective is to enable effecient transmission of all kinds of ATM traffic in the wireless channel with guaranteed QoS.The proposed protocol utilixes knowledge of the main...... guaranteed QoS requirements to a variety of ATM applications....

  14. Incentive Mechanism for P2P Content Sharing over Heterogenous Access Networks

    Science.gov (United States)

    Sato, Kenichiro; Hashimoto, Ryo; Yoshino, Makoto; Shinkuma, Ryoichi; Takahashi, Tatsuro

    In peer-to-peer (P2P) content sharing, users can share their content by contributing their own resources to one another. However, since there is no incentive for contributing contents or resources to others, users may attempt to obtain content without any contribution. To motivate users to contribute their resources to the service, incentive-rewarding mechanisms have been proposed. On the other hand, emerging wireless technologies, such as IEEE 802.11 wireless local area networks, beyond third generation (B3G) cellular networks and mobile WiMAX, provide high-speed Internet access for wireless users. Using these high-speed wireless access, wireless users can use P2P services and share their content with other wireless users and with fixed users. However, this diversification of access networks makes it difficult to appropriately assign rewards to each user according to their contributions. This is because the cost necessary for contribution is different in different access networks. In this paper, we propose a novel incentive-rewarding mechanism called EMOTIVER that can assign rewards to users appropriately. The proposed mechanism uses an external evaluator and interactive learning agents. We also investigate a way of appropriately controlling rewards based on the system service's quality and managing policy.

  15. Modeling the video distribution link in the Next Generation Optical Access Networks

    DEFF Research Database (Denmark)

    Amaya, F.; Cárdenas, A.; Tafur Monroy, Idelfonso

    2011-01-01

    In this work we present a model for the design and optimization of the video distribution link in the next generation optical access network. We analyze the video distribution performance in a SCM-WDM link, including the noise, the distortion and the fiber optic nonlinearities. Additionally, we c...

  16. Data Archiving and Networked Services (DANS) promotes sustained access to digital research data

    NARCIS (Netherlands)

    van Berchum, M.; Kraaikamp, Emilie

    2015-01-01

    Data Archiving and Networked Services (DANS) promotes sustained access to digital research data. For this purpose, DANS encourages researchers to archive and reuse data in a sustained form. In the online archiving system EASY research data is stored in a permanent and sustainable manner, according

  17. Dynamic optical fiber delivery of Ka-band packet transmissions for wireless access networks

    DEFF Research Database (Denmark)

    Rodríguez Páez, Juan Sebastián; Madsen, Peter; Tafur Monroy, Idelfonso

    2017-01-01

    A Reconfigurable Radio Access Unit is presented and experimentally demonstrated. In the unit, an optical switching system is set to dynamically deliver different packets to different points in the network. The packets are transmitted wirelesslty on the Ka-band (26–40 GHz), achieving BER values...

  18. Use and benefits of public access defibrillation in a nation-wide network

    DEFF Research Database (Denmark)

    Nielsen, Anne Møller; Folke, Fredrik; Lippert, Freddy Knudsen

    2013-01-01

    BACKGROUND: Automated External Defibrillators (AEDs) are known to increase survival after out-of-hospital cardiac arrest (OHCA). The aim of this study was to examine the use and benefit of public-access defibrillation (PAD) in a nation-wide network. We primarily sought to assess survival at 1 month...

  19. Analysis of the Decoupled Access for Downlink and Uplink in Wireless Heterogeneous Networks

    DEFF Research Database (Denmark)

    Smiljkovikj, K.; Popovski, Petar; Gavrilovska, L.

    2015-01-01

    Wireless cellular networks evolve towards a heterogeneous infrastructure, featuring multiple types of Base Stations (BSs), such as Femto BSs (FBSs) and Macro BSs (MBSs). A wireless device observes multiple points (BSs) through which it can access the infrastructure and it may choose to receive th...

  20. Optical network unit placement in Fiber-Wireless (FiWi) access network by Moth-Flame optimization algorithm

    Science.gov (United States)

    Singh, Puja; Prakash, Shashi

    2017-07-01

    Hybrid wireless-optical broadband access network (WOBAN) or Fiber-Wireless (FiWi) is the integration of wireless access network and optical network. This hybrid multi-domain network adopts the advantages of wireless and optical domains and serves the demand of technology savvy users. FiWi exhibits the properties of cost effectiveness, robustness, flexibility, high capacity, reliability and is self organized. Optical Network Unit (ONU) placement problem in FiWi contributes in simplifying the network design and enhances the performance in terms of cost efficiency and increased throughput. Several individual-based algorithms, such as Simulated Annealing (SA), Tabu Search, etc. have been suggested for ONU placement, but these algorithms suffer from premature convergence (trapping in a local optima). The present research work undertakes the deployment of FiWi and proposes a novel nature-inspired heuristic paradigm called Moth-Flame optimization (MFO) algorithm for multiple optical network units' placement. MFO is a population based algorithm. Population-based algorithms are better in handling local optima avoidance. The simulation results are compared with the existing Greedy and Simulated Annealing algorithms to optimize the position of ONUs. To the best of our knowledge, MFO algorithm has been used for the first time in this domain, moreover it has been able to provide very promising and competitive results. The performance of MFO algorithm has been analyzed by varying the 'b' parameter. MFO algorithm results in faster convergence than the existing strategies of Greedy and SA and returns a lower value of overall cost function. The results exhibit the dependence of the objective function on the distribution of wireless users also.

  1. CREATION OF THE SHUGHNANI DISCOURSE OF PUBLIC SPHERE IN THE MEDIA AND SOCIAL NETWORKS

    Directory of Open Access Journals (Sweden)

    П Ш Абдулхамидова

    2017-12-01

    Full Text Available Shughnani, one of the Pamiri languages of Tajikistan, is a minority language, and has no written script. Socio-economic and political changes in the lives of language speakers have affected the functioning of this small language, which was previously devoid of social significance. In the late 1980s, ideas began to emerge about the expansion of its functions, and attempts were made to use it in print media, television and radio. Observation of the functional development of Shugnani in these media led to the hypothesis of the emergence of a public sphere discourse, where it is possible to raise problems of social importance, and discuss them to search for eventual solutions. The main purpose of the article is to study attempts to create a discourse of the public sphere for Shugnani, in media and on the Facebook social network. The theoretical and methodological approaches of the study are based on the concept of the pub-lic sphere of Habermas, using the Critical Discourse Analysis paradigm (Fairclough. The data for the study were taken from Shughnani print media, from speeches on television and radio, and from postings by members of Shughnani Facebook groups. The findings reveal that the Shughnani presence in the media is limited, and construction of public opinion is more successfully carried out via Shughnani groups on Facebook. Analysis of the discursive practices involved shows that, despite the slow development of a media presence, the establishment of public discourse occurs through the creation of verbal units which have a journalistic character. Shugnani-speaking groups on Facebook contribute to the strengthening of the posi-tion of the language, through the formulation and discussion of issues relevant to members of the language community and the creation of language units that enhance confidence in the use of non-written Shugnani in the public sphere.

  2. Academic Social Networks and Open Access: French Researchers at the Crossroads

    Directory of Open Access Journals (Sweden)

    Christine Okret-Manville

    2016-01-01

    Full Text Available Researchers benefit from an increasing array of tools to enhance direct communication and the dissemination of their research findings. These include Open Access repositories, Open Access journals, or hybrid publishing. For some years, researchers have been using new ways to communicate and share their work by using academic social networks.In an attempt to foster the development of Open Access in France, the French consortium COUPERIN (Unified Consortium of Higher Education and Research Organizations for Access to Numerical Publications proposed that academic social networks could be used to convince researchers of becoming more involved in Open Access. To test this hypothesis, a nationwide survey was launched in 2014 to explore whether and how these academic social networks are used to share content, but also how they compare to other Open Access classic tools. Within a month (20 May to 20 June, 1,898 researchers answered this 28-question survey. It was fully completed by 1,698 of them. This provides COUPERIN with considerable data for analysis. The respondents roughly reflect the composition of the French academic community in terms of gender and research fields, with a slight overrepresentation of young researchers/ PhD candidates.This survey does not, however, cover the in-depth opinions of researchers on Open Access and academic social networks. It therefore only presents general tendencies. Nonetheless, the survey gives many indications as to how researchers apply Open Access. In addition, it shows how they feel about the usefulness of these networks compared to repositories when efficiently disseminating their work. This survey also takes the differences between disciplines into account and characterizes behaviour and opinions according to the different disciplinary communities and their research practices.Finally, this survey allows us to define the main characteristics of a tool which could meet French researchers’ needs for

  3. Partial Interference and Its Performance Impact on Wireless Multiple Access Networks

    Directory of Open Access Journals (Sweden)

    Lau WingCheong

    2010-01-01

    Full Text Available To determine the capacity of wireless multiple access networks, the interference among the wireless links must be accurately modeled. In this paper, we formalize the notion of the partial interference phenomenon observed in many recent wireless measurement studies and establish analytical models with tractable solutions for various types of wireless multiple access networks. In particular, we characterize the stability region of IEEE 802.11 networks under partial interference with two potentially unsaturated links numerically. We also provide a closed-form solution for the stability region of slotted ALOHA networks under partial interference with two potentially unsaturated links and obtain a partial characterization of the boundary of the stability region for the general M-link case. Finally, we derive a closed-form approximated solution for the stability region for general M-link slotted ALOHA system under partial interference effects. Based on our results, we demonstrate that it is important to model the partial interference effects while analyzing wireless multiple access networks. This is because such considerations can result in not only significant quantitative differences in the predicted system capacity but also fundamental qualitative changes in the shape of the stability region of the systems.

  4. Quantifying Network Dynamics and Information Flow Across Chinese Social Media During the African Ebola Outbreak.

    Science.gov (United States)

    Feng, Shihui; Hossain, Liaquat; Crawford, John W; Bossomaier, Terry

    2017-08-01

    Social media provides us with a new platform on which to explore how the public responds to disasters and, of particular importance, how they respond to the emergence of infectious diseases such as Ebola. Provided it is appropriately informed, social media offers a potentially powerful means of supporting both early detection and effective containment of communicable diseases, which is essential for improving disaster medicine and public health preparedness. The 2014 West African Ebola outbreak is a particularly relevant contemporary case study on account of the large number of annual arrivals from Africa, including Chinese employees engaged in projects in Africa. Weibo (Weibo Corp, Beijing, China) is China's most popular social media platform, with more than 2 billion users and over 300 million daily posts, and offers great opportunity to monitor early detection and promotion of public health awareness. We present a proof-of-concept study of a subset of Weibo posts during the outbreak demonstrating potential and identifying priorities for improving the efficacy and accuracy of information dissemination. We quantify the evolution of the social network topology within Weibo relating to the efficacy of information sharing. We show how relatively few nodes in the network can have a dominant influence over both the quality and quantity of the information shared. These findings make an important contribution to disaster medicine and public health preparedness from theoretical and methodological perspectives for dealing with epidemics. (Disaster Med Public Health Preparedness. 2017;page 1 of 12).

  5. Brand community integration and customer satisfaction of social media network sites among students

    Directory of Open Access Journals (Sweden)

    Hayford Amegbe

    2017-11-01

    Full Text Available The aim of the study was to examine how consumers integrate into brand communities on social media network sites (SNSs and how it affects overall satisfaction of social media sites users among students. The study depends on the service-dominant logic (SDL to develop the constructs for hypotheses testing. The study used a cross-sectional survey research design. The data were col-lected using a web-based survey of university of Nairobi Students. In all, a total of 608 students participated in the survey. The data was analyzed using structural equation modeling with AMOS software. The results revealed that frequency of usage of SNSs and duration of usage positively affect the self –perceived relevance of SNSs. Also, the self-perceived relevance leads to building brand community which finally leads to customer satisfaction. The research was limited to only students of Nairobi and selecting students in itself, which is a limitation as well as limiting it to uni-versity of Nairobi. The younger or the millennial are not the only users of SNSs. We have older generations as well, who also use SNSs for various activities such as professional development among others. Understanding why consumers of social media network site would integrate brand community is seminal for both local and foreign firms doing business in a developing country. This would enable marketing practitioners to craft marketing strategies best for community brand build-ing.

  6. Service-Oriented Access Control

    Science.gov (United States)

    2014-09-01

    Relay Chat LAN local area network MAC media access control mDNS Multicast DNS NAT network address translation OSPF Open Shortest Path First PDU protocol...Open Shortest Path First ( OSPF ), or Dynamic Host Configuration Protocol (DHCP)). An algorithm for SOAC must have control over all such organization

  7. Bandwidth Impacts of Localizing Peer-to-Peer IP Video Traffic in Access and Aggregation Networks

    Directory of Open Access Journals (Sweden)

    Kerpez Kenneth

    2008-01-01

    Full Text Available Abstract This paper examines the burgeoning impact of peer-to-peer (P2P traffic IP video traffic. High-quality IPTV or Internet TV has high-bandwidth requirements, and P2P IP video could severely strain broadband networks. A model for the popularity of video titles is given, showing that some titles are very popular and will often be available locally; making localized P2P attractive for video titles. The bandwidth impacts of localizing P2P video to try and keep traffic within a broadband access network area or within a broadband access aggregation network area are examined. Results indicate that such highly localized P2P video can greatly lower core bandwidth usage.

  8. Bandwidth Impacts of Localizing Peer-to-Peer IP Video Traffic in Access and Aggregation Networks

    Directory of Open Access Journals (Sweden)

    Kenneth Kerpez

    2008-10-01

    Full Text Available This paper examines the burgeoning impact of peer-to-peer (P2P traffic IP video traffic. High-quality IPTV or Internet TV has high-bandwidth requirements, and P2P IP video could severely strain broadband networks. A model for the popularity of video titles is given, showing that some titles are very popular and will often be available locally; making localized P2P attractive for video titles. The bandwidth impacts of localizing P2P video to try and keep traffic within a broadband access network area or within a broadband access aggregation network area are examined. Results indicate that such highly localized P2P video can greatly lower core bandwidth usage.

  9. Research on Czech firms’ marketing communication based on social media networks

    Directory of Open Access Journals (Sweden)

    Vít Chlebovský

    2012-01-01

    Full Text Available Objective of the research described in this article is to make an analysis of the usage of marketing communication using both traditional Internet communication channels as well as Social Media Networks by the Czech companies. Primary research was made through on-line questionnaire. Companies across the branches and size categories within the Czech economy were addressed. Companies were selected from the www.firmy.cz portal. Only companies with their own web domain were addressed. The typical respondents were mostly from middle management, especially managers from the marketing or commercial departments. The final number of questionnaire respondents covered in the research is 1009. The main research method was questioning. The questionnaire consisted of three sections with the scale answer questions mainly. Google Refine was used for data processing and Microsoft Excel for statistical processing and graphic outputs of the research. Evaluated results show significant gaps in usage of Internet communication tools in marketing of Czech companies and also deficiency between clear understanding of the respondents how Social Media should be used in marketing communication and real use in the companies. This deficiency was statistically tested and relation between respondents’ perception of the importance of Social Media use for bidirectional communication with stakeholders and non-use of Social Media for bidirectional communication with stakeholders by respondents’ company was confirmed.

  10. Stability of multiple access network control schemes with carrier sensing and exponential backoff

    Science.gov (United States)

    Barany, Ernest; Krupa, Maciej

    2006-05-01

    A new approach to determine the stability of multiple access network control schemes is presented. A “busy” network (the precise meaning of the term “busy” will be presented in the text) is modelled as a switched single-server hybrid dynamical system whose switching laws are stochastic and are based on typical multiple access network control protocols such as ALOHA and ethernet. The techniques are used to compute the critical ratio of traffic production per network node to total available bandwidth that ensures that data packets will not accumulate unboundedly in waiting queues at each node. This is a measure of stability of the network and is an emergent, global, property determined by decentralized, autonomous behavior of each node. The behavior of each individual node is regarded as “microscopic” and the collective behavior of the network as a whole are emergent consequences of such microscopic laws. The results follow from the stationary distribution property of ergodic Markov chains.

  11. ALPHA: Proposal of Mapping QoS Parameters between UPnP Home Network and GMPLS Access

    DEFF Research Database (Denmark)

    Brewka, Lukasz Jerzy; Sköldström, Pontus; Gavler, Anders

    2011-01-01

    This paper is treating the interdomain QoS signaling between the home and access domains with a focus on applying it for providing QoS between a UPnP-QoS based home network and GMPLS based access network. The work presented here is defining a possible approach for an interface between UPn...

  12. Network-based modeling and intelligent data mining of social media for improving care.

    Science.gov (United States)

    Akay, Altug; Dragomir, Andrei; Erlandsson, Bjorn-Erik

    2015-01-01

    Intelligently extracting knowledge from social media has recently attracted great interest from the Biomedical and Health Informatics community to simultaneously improve healthcare outcomes and reduce costs using consumer-generated opinion. We propose a two-step analysis framework that focuses on positive and negative sentiment, as well as the side effects of treatment, in users' forum posts, and identifies user communities (modules) and influential users for the purpose of ascertaining user opinion of cancer treatment. We used a self-organizing map to analyze word frequency data derived from users' forum posts. We then introduced a novel network-based approach for modeling users' forum interactions and employed a network partitioning method based on optimizing a stability quality measure. This allowed us to determine consumer opinion and identify influential users within the retrieved modules using information derived from both word-frequency data and network-based properties. Our approach can expand research into intelligently mining social media data for consumer opinion of various treatments to provide rapid, up-to-date information for the pharmaceutical industry, hospitals, and medical staff, on the effectiveness (or ineffectiveness) of future treatments.

  13. Retrieving quantifiable social media data from human sensor networks for disaster modeling and crisis mapping

    Science.gov (United States)

    Aulov, Oleg

    This dissertation presents a novel approach that utilizes quantifiable social media data as a human aware, near real-time observing system, coupled with geophysical predictive models for improved response to disasters and extreme events. It shows that social media data has the potential to significantly improve disaster management beyond informing the public, and emphasizes the importance of different roles that social media can play in management, monitoring, modeling and mitigation of natural and human-caused extreme disasters. In the proposed approach Social Media users are viewed as "human sensors" that are "deployed" in the field, and their posts are considered to be "sensor observations", thus different social media outlets all together form a Human Sensor Network. We utilized the "human sensor" observations, as boundary value forcings, to show improved geophysical model forecasts of extreme disaster events when combined with other scientific data such as satellite observations and sensor measurements. Several recent extreme disasters are presented as use case scenarios. In the case of the Deepwater Horizon oil spill disaster of 2010 that devastated the Gulf of Mexico, the research demonstrates how social media data from Flickr can be used as a boundary forcing condition of GNOME oil spill plume forecast model, and results in an order of magnitude forecast improvement. In the case of Hurricane Sandy NY/NJ landfall impact of 2012, we demonstrate how the model forecasts, when combined with social media data in a single framework, can be used for near real-time forecast validation, damage assessment and disaster management. Owing to inherent uncertainties in the weather forecasts, the NOAA operational surge model only forecasts the worst-case scenario for flooding from any given hurricane. Geolocated and time-stamped Instagram photos and tweets allow near real-time assessment of the surge levels at different locations, which can validate model forecasts, give

  14. Tobacco use, access, and exposure to tobacco in media among middle and high school students--United States, 2004.

    Science.gov (United States)

    2005-04-01

    Two of the national health objectives for 2010 are to reduce the prevalence of any tobacco use during the preceding month to cigarette use to students (objectives 27-2a and 27-2b). The National Youth Tobacco Survey (NYTS), conducted by CDC in 2004, provided estimates of current use of tobacco products and selected indicators related to tobacco use, including youth exposure to tobacco-related media and access to cigarettes. This report summarizes data from the 2004 NYTS and describes changes in tobacco use and indicators related to tobacco use since 2002. During 2002-2004, middle school students reported decreases in pipe use, seeing actors using tobacco on television or in movies, and seeing advertisements for tobacco products on the Internet. Among high school students, no changes were observed in the use of tobacco or in access to tobacco products; however, seeing actors using tobacco on television or in movies declined slightly, and seeing advertisements for tobacco products on the Internet increased. The lack of substantial decreases in the use of almost all tobacco products among middle and high school students underscores the need to fully implement evidence-based strategies (e.g., increasing the retail price of tobacco products, implementing smoking-prevention media campaigns, and decreasing minors' access as part of comprehensive tobacco-control programs) that are effective in preventing youth tobacco use.

  15. An Examination of Not-For-Profit Stakeholder Networks for Relationship Management: A Small-Scale Analysis on Social Media.

    Science.gov (United States)

    Wyllie, Jessica; Lucas, Benjamin; Carlson, Jamie; Kitchens, Brent; Kozary, Ben; Zaki, Mohamed

    2016-01-01

    Using a small-scale descriptive network analysis approach, this study highlights the importance of stakeholder networks for identifying valuable stakeholders and the management of existing stakeholders in the context of mental health not-for-profit services. We extract network data from the social media brand pages of three health service organizations from the U.S., U.K., and Australia, to visually map networks of 579 social media brand pages (represented by nodes), connected by 5,600 edges. This network data is analyzed using a collection of popular graph analysis techniques to assess the differences in the way each of the service organizations manage stakeholder networks. We also compare node meta-information against basic topology measures to emphasize the importance of effectively managing relationships with stakeholders who have large external audiences. Implications and future research directions are also discussed.

  16. An Examination of Not-For-Profit Stakeholder Networks for Relationship Management: A Small-Scale Analysis on Social Media.

    Directory of Open Access Journals (Sweden)

    Jessica Wyllie

    Full Text Available Using a small-scale descriptive network analysis approach, this study highlights the importance of stakeholder networks for identifying valuable stakeholders and the management of existing stakeholders in the context of mental health not-for-profit services. We extract network data from the social media brand pages of three health service organizations from the U.S., U.K., and Australia, to visually map networks of 579 social media brand pages (represented by nodes, connected by 5,600 edges. This network data is analyzed using a collection of popular graph analysis techniques to assess the differences in the way each of the service organizations manage stakeholder networks. We also compare node meta-information against basic topology measures to emphasize the importance of effectively managing relationships with stakeholders who have large external audiences. Implications and future research directions are also discussed.

  17. An Examination of Not-For-Profit Stakeholder Networks for Relationship Management: A Small-Scale Analysis on Social Media

    Science.gov (United States)

    Carlson, Jamie; Kitchens, Brent; Kozary, Ben; Zaki, Mohamed

    2016-01-01

    Using a small-scale descriptive network analysis approach, this study highlights the importance of stakeholder networks for identifying valuable stakeholders and the management of existing stakeholders in the context of mental health not-for-profit services. We extract network data from the social media brand pages of three health service organizations from the U.S., U.K., and Australia, to visually map networks of 579 social media brand pages (represented by nodes), connected by 5,600 edges. This network data is analyzed using a collection of popular graph analysis techniques to assess the differences in the way each of the service organizations manage stakeholder networks. We also compare node meta-information against basic topology measures to emphasize the importance of effectively managing relationships with stakeholders who have large external audiences. Implications and future research directions are also discussed. PMID:27711236

  18. Access, engagement, networks, and norms: Dimensions of social capital at work in a first grade classroom

    Science.gov (United States)

    Wexler-Robock, Stephanie

    Social capital refers to access and use of resources available through one's networks to solve problems, and the norms that reflect inclusive or exclusive access to those networks and resources. Research has found positive relationships between social capital, academic achievement, and attainment. Studies, however, have generally examined social capital through factors that occur outside the classroom; students who have social capital, acquired through their family and community relationships, seem to be more successful academically. Limited research has explored what if any factors within the classroom might impact the production, and nature of social capital, or its workings in a classroom. The purpose of this study was to explore the workings and nature of classroom social capital, including its possible relationships to engagement and cognition among 5 student participants. Using methods of qualitative data collection, mixed methods were used to analyze information resources, participants' networking, student work, and classroom discourse. Eight interdependent networking factors and 3 overarching patterns of norms were discovered. The networking factors reflected the structure, content, processes, purposes, and acceptability of participants' networking. The norms, also working interdependently, appeared to promote or inhibit among other things, engagement in networking, help seeking, access, sharing, and intertextual use of diverse, often complex sources of information. Through interaction of the 8 factors and 3 overarching norms, ongoing outcomes of networking appeared to include the creation of bridging (inclusive) and bonding (exclusive) forms of social capital, and depth of scientific conceptual understanding, in this case, about birds. Bridging social capital appeared related to willingness to engage in strong and weak tie networking, help seeking, intertextuality, and possibly to mastery goal orientation for all participants, regardless of reading level

  19. An Adaptive Channel Access Method for Dynamic Super Dense Wireless Sensor Networks.

    Science.gov (United States)

    Lei, Chunyang; Bie, Hongxia; Fang, Gengfa; Zhang, Xuekun

    2015-12-03

    Super dense and distributed wireless sensor networks have become very popular with the development of small cell technology, Internet of Things (IoT), Machine-to-Machine (M2M) communications, Vehicular-to-Vehicular (V2V) communications and public safety networks. While densely deployed wireless networks provide one of the most important and sustainable solutions to improve the accuracy of sensing and spectral efficiency, a new channel access scheme needs to be designed to solve the channel congestion problem introduced by the high dynamics of competing nodes accessing the channel simultaneously. In this paper, we firstly analyzed the channel contention problem using a novel normalized channel contention analysis model which provides information on how to tune the contention window according to the state of channel contention. We then proposed an adaptive channel contention window tuning algorithm in which the contention window tuning rate is set dynamically based on the estimated channel contention level. Simulation results show that our proposed adaptive channel access algorithm based on fast contention window tuning can achieve more than 95 % of the theoretical optimal throughput and 0 . 97 of fairness index especially in dynamic and dense networks.

  20. The role of social media networks in psychotic disorders: a case report.

    Science.gov (United States)

    Krishna, Nithin; Fischer, Bernard A; Miller, Moshe; Register-Brown, Kelly; Patchan, Kathleen; Hackman, Ann

    2013-01-01

    We report the case of a young man diagnosed with schizophrenia who presented with stalking behaviors that may have been caused by problematic use or participation in social media networks (SMN). We review the possible role of SMN in the formation of his romantic delusion and offer suggestions for clinicians around incorporation of SMN questions into assessments. It is imperative to identify populations at risk of SMN-related stalking behaviors to stratify mental health resources and interventions. Additional studies are needed to further clarify the role of SMN in psychotic disorders. Copyright © 2013 Elsevier Inc. All rights reserved.

  1. The Access Gap: Poverty and Characteristics of School Library Media Centers

    Science.gov (United States)

    Pribesh, Shana; Gavigan, Karen; Dickinson, Gail

    2011-01-01

    Stephen Krashen believes that schools can counter the effects of poverty in at least one area: access to books. However, little research has been done to determine whether students living in poverty have access to school library services comparable to those attending schools with low concentrations of students living in poverty. We examined the…

  2. A novel and efficient user access control scheme for wireless body area sensor networks

    Directory of Open Access Journals (Sweden)

    Santanu Chatterjee

    2014-07-01

    Full Text Available Wireless body area networks (WBANs can be applied to provide healthcare and patient monitoring. However, patient privacy can be vulnerable in a WBAN unless security is considered. Access to authorized users for the correct information and resources for different services can be provided with the help of efficient user access control mechanisms. This paper proposes a new user access control scheme for a WBAN. The proposed scheme makes use of a group-based user access ID, an access privilege mask, and a password. An elliptic curve cryptography-based public key cryptosystem is used to ensure that a particular legitimate user can only access the information for which he/she is authorized. We show that our scheme performs better than previously existing user access control schemes. Through a security analysis, we show that our scheme is secure against possible known attacks. Furthermore, through a formal security verification using the AVISPA (Automated Validation of Internet Security Protocols and Applications tool, we show that our scheme is also secure against passive and active attacks.

  3. Comparison of a Ring On-Chip Network and a Code-Division Multiple-Access On-Chip Network

    Directory of Open Access Journals (Sweden)

    Xin Wang

    2007-01-01

    Full Text Available Two network-on-chip (NoC designs are examined and compared in this paper. One design applies a bidirectional ring connection scheme, while the other design applies a code-division multiple-access (CDMA connection scheme. Both of the designs apply globally asynchronous locally synchronous (GALS scheme in order to deal with the issue of transferring data in a multiple-clock-domain environment of an on-chip system. The two NoC designs are compared with each other by their network structures, data transfer principles, network node structures, and their asynchronous designs. Both the synchronous and the asynchronous designs of the two on-chip networks are realized using a hardware-description language (HDL in order to make the entire designs suit the commonly used synchronous design tools and flow. The performance estimation and comparison of the two NoC designs which are based on the HDL realizations are addressed. By comparing the two NoC designs, the advantages and disadvantages of applying direct connection and CDMA connection schemes in an on-chip communication network are discussed.

  4. Tractable Stochastic Geometry Model for IoT Access in LTE Networks

    KAUST Repository

    Gharbieh, Mohammad

    2017-02-07

    The Internet of Things (IoT) is large-scale by nature. This is not only manifested by the large number of connected devices, but also by the high volumes of traffic that must be accommodated. Cellular networks are indeed a natural candidate for the data tsunami the IoT is expected to generate in conjunction with legacy human-type traffic. However, the random access process for scheduling request represents a major bottleneck to support IoT via LTE cellular networks. Accordingly, this paper develops a mathematical framework to model and study the random access channel (RACH) scalability to accommodate IoT traffic. The developed model is based on stochastic geometry and discrete time Markov chains (DTMC) to account for different access strategies and possible sources of inter-cell and intra-cell interferences. To this end, the developed model is utilized to assess and compare three different access strategies, which incorporate a combination of transmission persistency, back-off, and power ramping. The analysis and the results showcased herewith clearly illustrate the vulnerability of the random access procedure as the IoT intensity grows. Finally, the paper offers insights into effective scenarios for each transmission strategy in terms of IoT intensity and RACH detection thresholds.

  5. Switched-based interference reduction scheme for open-access overlaid cellular networks

    KAUST Repository

    Radaydeh, Redha Mahmoud Mesleh

    2012-06-01

    Femtocells have been proposed to enhance the spatial coverage and system capacity of existing cellular networks. However, this technology may result in significant performance loss due to the increase in co-channel interference, particularly when coordination between access points is infeasible. This paper targets interference management in such overlaid networks. It is assumed that the femtocells employ the open-access strategy to reduce cross-tier interference, and can share resources concurrently. It is also assumed that each end user (EU) can access one channel at a time, and transfer limited feedback. To reduce the effect of co-tier interference in the absence of the desired EU channel state information (CSI) at the serving access point as well as coordination between active access points, a switched scheme based on the interference levels associated with available channels is proposed. Through the analysis, the scheme modes of operation in under-loaded and over-loaded channels are studied, from which the statistics of the resulting interference power are quantified. The impact of the proposed scheme on the received desired power is thoroughly discussed. In addition, the effect of the switching threshold on the achieved performance of the desired EU is investigated. The results clarify that the proposed scheme can improve the performance while reducing the number of examined channels and feedback load. © 2012 IEEE.

  6. In situ bioremediation: A network model of diffusion and flow in granular porous media

    Energy Technology Data Exchange (ETDEWEB)

    Griffiths, S.K.; Nilson, R.H.; Bradshaw, R.W.

    1997-04-01

    In situ bioremediation is a potentially expedient, permanent and cost- effective means of waste site decontamination. However, permeability reductions due to the transport and deposition of native fines or due to excessive microorganism populations may severely inhibit the injection of supplemental oxygen in the contamination zone. To help understand this phenomenon, we have developed a micro-mechanical network model of flow, diffusion and particle transport in granular porous materials. The model differs from most similar models in that the network is defined by particle positions in a numerically-generated particle array. The model is thus widely applicable to computing effective transport properties for both ordered and realistic random porous media. A laboratory-scale apparatus to measure permeability reductions has also been designed, built and tested.

  7. PANATIKI: a network access control implementation based on PANA for IoT devices.

    Science.gov (United States)

    Moreno Sanchez, Pedro; Marin Lopez, Rafa; Gomez Skarmeta, Antonio F

    2013-11-01

    Internet of Things (IoT) networks are the pillar of recent novel scenarios, such as smart cities or e-healthcare applications. Among other challenges, these networks cover the deployment and interaction of small devices with constrained capabilities and Internet protocol (IP)-based networking connectivity. These constrained devices usually require connection to the Internet to exchange information (e.g., management or sensing data) or access network services. However, only authenticated and authorized devices can, in general, establish this connection. The so-called authentication, authorization and accounting (AAA) services are in charge of performing these tasks on the Internet. Thus, it is necessary to deploy protocols that allow constrained devices to verify their credentials against AAA infrastructures. The Protocol for Carrying Authentication for Network Access (PANA) has been standardized by the Internet engineering task force (IETF) to carry the Extensible Authentication Protocol (EAP), which provides flexible authentication upon the presence of AAA. To the best of our knowledge, this paper is the first deep study of the feasibility of EAP/PANA for network access control in constrained devices. We provide light-weight versions and implementations of these protocols to fit them into constrained devices. These versions have been designed to reduce the impact in standard specifications. The goal of this work is two-fold: (1) to demonstrate the feasibility of EAP/PANA in IoT devices; (2) to provide the scientific community with the first light-weight interoperable implementation of EAP/PANA for constrained devices in the Contiki operating system (Contiki OS), called PANATIKI. The paper also shows a testbed, simulations and experimental results obtained from real and simulated constrained devices.

  8. PANATIKI: A Network Access Control Implementation Based on PANA for IoT Devices

    Directory of Open Access Journals (Sweden)

    Antonio F. Gomez Skarmeta

    2013-11-01

    Full Text Available Internet of Things (IoT networks are the pillar of recent novel scenarios, such as smart cities or e-healthcare applications. Among other challenges, these networks cover the deployment and interaction of small devices with constrained capabilities and Internet protocol (IP-based networking connectivity. These constrained devices usually require connection to the Internet to exchange information (e.g., management or sensing data or access network services. However, only authenticated and authorized devices can, in general, establish this connection. The so-called authentication, authorization and accounting (AAA services are in charge of performing these tasks on the Internet. Thus, it is necessary to deploy protocols that allow constrained devices to verify their credentials against AAA infrastructures. The Protocol for Carrying Authentication for Network Access (PANA has been standardized by the Internet engineering task force (IETF to carry the Extensible Authentication Protocol (EAP, which provides flexible authentication upon the presence of AAA. To the best of our knowledge, this paper is the first deep study of the feasibility of EAP/PANA for network access control in constrained devices. We provide light-weight versions and implementations of these protocols to fit them into constrained devices. These versions have been designed to reduce the impact in standard specifications. The goal of this work is two-fold: (1 to demonstrate the feasibility of EAP/PANA in IoT devices; (2 to provide the scientific community with the first light-weight interoperable implementation of EAP/PANA for constrained devices in the Contiki operating system (Contiki OS, called PANATIKI. The paper also shows a testbed, simulations and experimental results obtained from real and simulated constrained devices.

  9. Gain transient control for wavelength division multiplexed access networks using semiconductor optical amplifiers

    DEFF Research Database (Denmark)

    Gibbon, Timothy Braidwood; Osadchiy, Alexey Vladimirovich; Kjær, Rasmus

    2009-01-01

    measurements how a near-saturated semiconductor optical amplifier (SOA) can be used to control these gain transients. An SOA is shown to reduce the penalty of transients originating in an EDFA from 2.3 dB to 0.2 dB for 10 Gb/s transmission over standard single mode fiber using a 231-1 PRBS pattern. The results......Gain transients can severely hamper the upstream network performance in wavelength division multiplexed (WDM) access networks featuring erbium doped fiber amplifiers (EDFAs) or Raman amplification. We experimentally demonstrate for the first time using 10 Gb/s fiber transmission bit error rate...

  10. New resource allocation scheme for cognitive relay networks with opportunistic access

    KAUST Repository

    Zafar, Ammar

    2012-06-01

    In this paper, a new resource allocation scheme to minimize Symbol Error rate (SER) for relay assisted cognitive radio networks is studied. A cognitive relay network with amplify-and-forward (AF) fixed gain relays and opportunistic access to the licensed spectrum is considered. The SER objective function and the optimization constraints are derived first. The resource allocation algorithm is then derived using the Langrangian multiplier method. Closed form expressions are derived for the source and relay powers and, symbol time. Analytical results show that the optimal power allocation follows an extended water-filling solution. © 2012 IEEE.

  11. The relative importance of social media for accessing, finding, and engaging with news

    DEFF Research Database (Denmark)

    Nielsen, Rasmus Kleis; Schrøder, Kim Christian

    2014-01-01

    , but also important country-to-country differences, in particular in terms of how widespread the more active and participatory forms of media use are. Surprisingly, these differences do not correspond to differences in levels of internet use, suggesting that more than mere availability shapes the role...

  12. Medium access control and network layer design for 60 GHz wireless personal area networks

    NARCIS (Netherlands)

    An, X.

    2010-01-01

    The unlicensed frequency band around 60 GHz is a very promising spectrum due to its potential to provide multiple gigabits per second based data rates for short range wireless communication. Hence, 60 GHz radio is an attractive candidate to enable ultra high rate Wireless Personal Area Networks

  13. Social features of online networks: the strength of intermediary ties in online social media.

    Directory of Open Access Journals (Sweden)

    Przemyslaw A Grabowicz

    Full Text Available An increasing fraction of today's social interactions occur using online social media as communication channels. Recent worldwide events, such as social movements in Spain or revolts in the Middle East, highlight their capacity to boost people's coordination. Online networks display in general a rich internal structure where users can choose among different types and intensity of interactions. Despite this, there are still open questions regarding the social value of online interactions. For example, the existence of users with millions of online friends sheds doubts on the relevance of these relations. In this work, we focus on Twitter, one of the most popular online social networks, and find that the network formed by the basic type of connections is organized in groups. The activity of the users conforms to the landscape determined by such groups. Furthermore, Twitter's distinction between different types of interactions allows us to establish a parallelism between online and offline social networks: personal interactions are more likely to occur on internal links to the groups (the weakness of strong ties; events transmitting new information go preferentially through links connecting different groups (the strength of weak ties or even more through links connecting to users belonging to several groups that act as brokers (the strength of intermediary ties.

  14. The neural correlates of persuasion: a common network across cultures and media.

    Science.gov (United States)

    Falk, Emily B; Rameson, Lian; Berkman, Elliot T; Liao, Betty; Kang, Yoona; Inagaki, Tristen K; Lieberman, Matthew D

    2010-11-01

    Persuasion is at the root of countless social exchanges in which one person or group is motivated to have another share its beliefs, desires, or behavioral intentions. Here, we report the first three functional magnetic resonance imaging studies to investigate the neurocognitive networks associated with feeling persuaded by an argument. In the first two studies, American and Korean participants, respectively, were exposed to a number of text-based persuasive messages. In both Study 1 and Study 2, feeling persuaded was associated with increased activity in posterior superior temporal sulcus bilaterally, temporal pole bilaterally, and dorsomedial prefrontal cortex. The findings suggest a discrete set of underlying mechanisms in the moment that the persuasion process occurs, and are strengthened by the fact that the results replicated across two diverse linguistic and cultural groups. Additionally, a third study using region-of-interest analyses demonstrated that neural activity in this network was also associated with persuasion when a sample of American participants viewed video-based messages. In sum, across three studies, including two different cultural groups and two types of media, persuasion was associated with a consistent network of regions in the brain. Activity in this network has been associated with social cognition and mentalizing and is consistent with models of persuasion that emphasize the importance of social cognitive processing in determining the efficacy of persuasive communication.

  15. Social features of online networks: the strength of intermediary ties in online social media.

    Science.gov (United States)

    Grabowicz, Przemyslaw A; Ramasco, José J; Moro, Esteban; Pujol, Josep M; Eguiluz, Victor M

    2012-01-01

    An increasing fraction of today's social interactions occur using online social media as communication channels. Recent worldwide events, such as social movements in Spain or revolts in the Middle East, highlight their capacity to boost people's coordination. Online networks display in general a rich internal structure where users can choose among different types and intensity of interactions. Despite this, there are still open questions regarding the social value of online interactions. For example, the existence of users with millions of online friends sheds doubts on the relevance of these relations. In this work, we focus on Twitter, one of the most popular online social networks, and find that the network formed by the basic type of connections is organized in groups. The activity of the users conforms to the landscape determined by such groups. Furthermore, Twitter's distinction between different types of interactions allows us to establish a parallelism between online and offline social networks: personal interactions are more likely to occur on internal links to the groups (the weakness of strong ties); events transmitting new information go preferentially through links connecting different groups (the strength of weak ties) or even more through links connecting to users belonging to several groups that act as brokers (the strength of intermediary ties).

  16. Social Features of Online Networks: The Strength of Intermediary Ties in Online Social Media

    Science.gov (United States)

    Grabowicz, Przemyslaw A.; Ramasco, José J.; Moro, Esteban; Pujol, Josep M.; Eguiluz, Victor M.

    2012-01-01

    An increasing fraction of today's social interactions occur using online social media as communication channels. Recent worldwide events, such as social movements in Spain or revolts in the Middle East, highlight their capacity to boost people's coordination. Online networks display in general a rich internal structure where users can choose among different types and intensity of interactions. Despite this, there are still open questions regarding the social value of online interactions. For example, the existence of users with millions of online friends sheds doubts on the relevance of these relations. In this work, we focus on Twitter, one of the most popular online social networks, and find that the network formed by the basic type of connections is organized in groups. The activity of the users conforms to the landscape determined by such groups. Furthermore, Twitter's distinction between different types of interactions allows us to establish a parallelism between online and offline social networks: personal interactions are more likely to occur on internal links to the groups (the weakness of strong ties); events transmitting new information go preferentially through links connecting different groups (the strength of weak ties) or even more through links connecting to users belonging to several groups that act as brokers (the strength of intermediary ties). PMID:22247773

  17. QUESTDONE APPLICATION WITH SOCIAL NETWORKING FEATURES AS THE ACTUAL WORLD INTERACTION MEDIA ON ANDROID SMARTPHONE

    Directory of Open Access Journals (Sweden)

    Rhio Sutoyo

    2012-10-01

    Full Text Available The purpose of this research is the design and implementation of an application that allows users to play and socialize at the same time and directly with the environment around the Android-based smart phone. This application is also expected to be a campaign media for a new product or specific event. The used method consists of two ways: the methods of analysis and design. The method of analysis includes the study of literatures, questionnaires, and comparisons with similar applications. The design method used for this research is Scrum. The obtained results are an application that helps users of Android-based smart phone to do social interaction and provide knowledge about the route that users will be addressed. It is also used as a new campaign media for entrepreneurs who want to promote a product or event. Furthermore, this application is also built with interesting but not complex design, thus allowing users to easily use it. The conclusions are this application provides experience for users to visit various places and can be a media campaign for a new product or specific event. It also becomes a tool of social interaction and useful for finding location of friends.Keywords: Applications; Social Networking; Interaction; Real World; Smartphone; Android

  18. Digital Media Platforms and Education: The Uses of Social Networking in the UAE and China

    Directory of Open Access Journals (Sweden)

    Badreya Aljenaibi

    2015-07-01

    Full Text Available Young people today are growing up in a digitalized environment.  What challenges do they face in navigating this content-rich, symbolic environment? In this article, the researcher reviews university students' perceptions of media literacy by examining the use of social networking platforms (SN in academic settings. The researcher distributed 1200 surveys evenly split between Chinese and UAE students and 998 were returned and analyzed. The findings reveal that while many students believe that media literacy should become a priority in modern curricula, this urgency is not felt by the majority of students.  The researcher reviews current views and methodologies in the literature related to media literacy and its status in current pedagogy.  The study draws from gravitation theory to place the use of SN tools within a broader background of communication.  The Uses and Gratification Theory is also invoked to explain how SN was made attractive to campus activists and protesters in the two countries.

  19. Convergent optical wired and wireless long-reach access network using high spectral-efficient modulation.

    Science.gov (United States)

    Chow, C W; Lin, Y H

    2012-04-09

    To provide broadband services in a single and low cost perform, the convergent optical wired and wireless access network is promising. Here, we propose and demonstrate a convergent optical wired and wireless long-reach access networks based on orthogonal wavelength division multiplexing (WDM). Both the baseband signal and the radio-over-fiber (ROF) signal are multiplexed and de-multiplexed in optical domain, hence it is simple and the operation speed is not limited by the electronic bottleneck caused by the digital signal processing (DSP). Error-free de-multiplexing and down-conversion can be achieved for all the signals after 60 km (long-reach) fiber transmission. The scalability of the system for higher bit-rate (60 GHz) is also simulated and discussed.

  20. Coalitional Games in Partition Form for Joint Spectrum Sensing and Access in Cognitive Radio Networks

    CERN Document Server

    Saad, Walid; Zheng, Rong; Hjørungnes, Are; Başar, Tamer; Poor, H Vincent

    2012-01-01

    Unlicensed secondary users (SUs) in cognitive radio networks are subject to an inherent tradeoff between spectrum sensing and spectrum access. Although each SU has an incentive to sense the primary user (PU) channels for locating spectrum holes, this exploration of the spectrum can come at the expense of a shorter transmission time, and, hence, a possibly smaller capacity for data transmission. This paper investigates the impact of this tradeoff on the cooperative strategies of a network of SUs that seek to cooperate in order to improve their view of the spectrum (sensing), reduce the possibility of interference among each other, and improve their transmission capacity (access). The problem is modeled as a coalitional game in partition form and an algorithm for coalition formation is proposed. Using the proposed algorithm, the SUs can make individual distributed decisions to join or leave a coalition while maximizing their utilities which capture the average time spent for sensing as well as the capacity achi...

  1. Design and implementation of fingerprint access control system based on ZigBee wireless network

    Directory of Open Access Journals (Sweden)

    Zhang Jin

    2017-01-01

    Full Text Available this paper mainly introduces a kind of fingerprint access control system based on ZigBee wireless network design and implementation method, specify when passengers should fingerprints collected and stored in the system at the information desk PC, and then assign rooms;Guests entered the room according to the fingerprint module, the system will be fingerprint information through ZigBee coordinator node module and network to transmit the fingerprint characteristic value to management system and the fingerprint information stored, if consistent with the electromagnetic lock open, allowed to enter the room, does not conform to the issued a warning sound.Additional access control system can control the corresponding fingerprint information storage room and remove, such as is required for a security incident broke in situation is special open mode can be set up.System software design consists of two aspects of the bottom and upper machine.

  2. Quantitative analysis of access strategies to remote information in network services

    DEFF Research Database (Denmark)

    Olsen, Rasmus Løvenstein; Schwefel, Hans-Peter; Hansen, Martin Bøgsted

    2006-01-01

    Remote access to dynamically changing information elements is a required functionality for various network services, including routing and instances of context-sensitive networking. Three fundamentally different strategies for such access are investigated in this paper: (1) a reactive approach...... initiated by the requesting entity, and two versions of proactive approaches in which the entity that contains the information element actively propagates its changes to potential requesters, either (2) periodically or triggered by changes of the information element (3). This paper first develops a set...... of analytic models to compute different performance metrics for these approaches, with special focus on the so-called mismatch probability. The results of the analytic models allow for design decisions on which strategy to implement for specific input parameters (change rate of the information element...

  3. The media and access issues: content analysis of Canadian newspaper coverage of health policy decisions

    National Research Council Canada - National Science Library

    Rachul, Christen; Caulfield, Timothy

    2015-01-01

    .... In order to test this hypothesis, we conducted a content analysis of 530 news articles about access to health therapies and technologies from 15 major Canadian newspapers over a 10-year period...

  4. Pore network modeling of drainage process in patterned porous media: a quasi-static study

    KAUST Repository

    Zhang, Tao

    2015-04-17

    This work represents a preliminary investigation on the role of wettability conditions on the flow of a two-phase system in porous media. Since such effects have been lumped implicitly in relative permeability-saturation and capillary pressure-saturation relationships, it is quite challenging to isolate its effects explicitly in real porous media applications. However, within the framework of pore network models, it is easy to highlight the effects of wettability conditions on the transport of two-phase systems. We employ quasi-static investigation in which the system undergo slow movement based on slight increment of the imposed pressure. Several numerical experiments of the drainage process are conducted to displace a wetting fluid with a non-wetting one. In all these experiments the network is assigned different scenarios of various wettability patterns. The aim is to show that the drainage process is very much affected by the imposed pattern of wettability. The wettability conditions are imposed by assigning the value of contact angle to each pore throat according to predefined patterns.

  5. Situational Awareness based Risk-Adapatable Access Control in Enterprise Networks

    OpenAIRE

    Lee, Brian; Vanickis, Roman; Rogelio, Franklin; Jacob, Paul

    2017-01-01

    As the computing landscape evolves towards distributed architectures such as Internet of Things (IoT),enterprises are moving away from traditional perimeter based security models toward so called zero trust networking (ZTN) models that treat both the intranet and Internet as equally untrustworthy. Such security models incorporate risk arising from dynamic and situational factors, such as device location and security risk level risk, into the access control decision. Researchers have developed...

  6. Optimizing data access for wind farm control over hierarchical communication networks

    DEFF Research Database (Denmark)

    Madsen, Jacob Theilgaard; Findrik, Mislav; Madsen, Tatiana Kozlova

    2016-01-01

    In this paper we investigate a centralized wind farm controller which runs periodically. The controller attempts to reduce the damage a wind turbine sustains during operation by estimating fatigue based on the wind turbine state. The investigation focuses on the impact of information access...... with respect to the communication network delays. These measurements are done in regards to packet loss and communication delays, and the simulations are rerun using either the traces from the measurements or scenarios constructed from the delay parameters....

  7. Cognitive Self-Scheduled Mechanism for Access Control in Noisy Vehicular Ad Hoc Networks

    Directory of Open Access Journals (Sweden)

    Mario Manzano

    2015-01-01

    Full Text Available Within the challenging environment of intelligent transportation systems (ITS, networked control systems such as platooning guidance of autonomous vehicles require innovative mechanisms to provide real-time communications. Although several proposals are currently under discussion, the design of a rapid, efficient, flexible, and reliable medium access control mechanism which meets the specific constraints of such real-time communications applications remains unsolved in this highly dynamic environment. However, cognitive radio (CR combines the capacity to sense the radio spectrum with the flexibility to adapt to transmission parameters in order to maximize system performance and has thus become an effective approach for the design of dynamic spectrum access (DSA mechanisms. This paper presents the enhanced noncooperative cognitive division multiple access (ENCCMA proposal combining time division multiple access (TDMA and frequency division multiple access (FDMA schemes with CR techniques to obtain a mechanism fulfilling the requirements of real-time communications. The analysis presented here considers the IEEE WAVE and 802.11p as reference standards; however, the proposed medium access control (MAC mechanism can be adapted to operate on the physical layer of different standards. The mechanism also offers the advantage of avoiding signaling, thus enhancing system autonomy as well as behavior in adverse scenarios.

  8. Trust-Based Access Control Model from Sociological Approach in Dynamic Online Social Network Environment

    Science.gov (United States)

    Kim, Seungjoo

    2014-01-01

    There has been an explosive increase in the population of the OSN (online social network) in recent years. The OSN provides users with many opportunities to communicate among friends and family. Further, it facilitates developing new relationships with previously unknown people having similar beliefs or interests. However, the OSN can expose users to adverse effects such as privacy breaches, the disclosing of uncontrolled material, and the disseminating of false information. Traditional access control models such as MAC, DAC, and RBAC are applied to the OSN to address these problems. However, these models are not suitable for the dynamic OSN environment because user behavior in the OSN is unpredictable and static access control imposes a burden on the users to change the access control rules individually. We propose a dynamic trust-based access control for the OSN to address the problems of the traditional static access control. Moreover, we provide novel criteria to evaluate trust factors such as sociological approach and evaluate a method to calculate the dynamic trust values. The proposed method can monitor negative behavior and modify access permission levels dynamically to prevent the indiscriminate disclosure of information. PMID:25374943

  9. Trust-Based Access Control Model from Sociological Approach in Dynamic Online Social Network Environment

    Directory of Open Access Journals (Sweden)

    Seungsoo Baek

    2014-01-01

    Full Text Available There has been an explosive increase in the population of the OSN (online social network in recent years. The OSN provides users with many opportunities to communicate among friends and family. Further, it facilitates developing new relationships with previously unknown people having similar beliefs or interests. However, the OSN can expose users to adverse effects such as privacy breaches, the disclosing of uncontrolled material, and the disseminating of false information. Traditional access control models such as MAC, DAC, and RBAC are applied to the OSN to address these problems. However, these models are not suitable for the dynamic OSN environment because user behavior in the OSN is unpredictable and static access control imposes a burden on the users to change the access control rules individually. We propose a dynamic trust-based access control for the OSN to address the problems of the traditional static access control. Moreover, we provide novel criteria to evaluate trust factors such as sociological approach and evaluate a method to calculate the dynamic trust values. The proposed method can monitor negative behavior and modify access permission levels dynamically to prevent the indiscriminate disclosure of information.

  10. Delay-aware adaptive sleep mechanism for green wireless-optical broadband access networks

    Science.gov (United States)

    Wang, Ruyan; Liang, Alei; Wu, Dapeng; Wu, Dalei

    2017-07-01

    Wireless-Optical Broadband Access Network (WOBAN) is capacity-high, reliable, flexible, and ubiquitous, as it takes full advantage of the merits from both optical communication and wireless communication technologies. Similar to other access networks, the high energy consumption poses a great challenge for building up WOBANs. To shot this problem, we can make some load-light Optical Network Units (ONUs) sleep to reduce the energy consumption. Such operation, however, causes the increased packet delay. Jointly considering the energy consumption and transmission delay, we propose a delay-aware adaptive sleep mechanism. Specifically, we develop a new analytical method to evaluate the transmission delay and queuing delay over the optical part, instead of adopting M/M/1 queuing model. Meanwhile, we also analyze the access delay and queuing delay of the wireless part. Based on such developed delay models, we mathematically derive ONU's optimal sleep time. In addition, we provide numerous simulation results to show the effectiveness of the proposed mechanism.

  11. An Access Control Protocol for Wireless Sensor Network Using Double Trapdoor Chameleon Hash Function

    Directory of Open Access Journals (Sweden)

    Tejeshwari Thakur

    2016-01-01

    Full Text Available Wireless sensor network (WSN, a type of communication system, is normally deployed into the unattended environment where the intended user can get access to the network. The sensor nodes collect data from this environment. If the data are valuable and confidential, then security measures are needed to protect them from the unauthorized access. This situation requires an access control protocol (ACP in the design of sensor network because of sensor nodes which are vulnerable to various malicious attacks during the authentication and key establishment and the new node addition phase. In this paper, we propose a secured ACP for such WSN. This protocol is based on Elliptic Curve Discrete Log Problem (ECDLP and double trapdoor chameleon hash function which secures the WSN from malicious attacks such as node masquerading attack, replay attack, man-in-the-middle attack, and forgery attacks. Proposed ACP has a special feature known as session key security. Also, the proposed ACP is more efficient as it requires only one modular multiplication during the initialization phase.

  12. The accessibility of Poland’s Space to the Trans-European Transport Network

    Directory of Open Access Journals (Sweden)

    Wiśniewski Szymon

    2017-09-01

    Full Text Available The aim of the article is to analyse the land transport accessibility of two trans-European corridors within the boundaries of Poland. The adjustment of the course of transport routes to the distribution of the population and the country’s land development (including economic potential and logistic infrastructure was outlined using measurements of cumulative accessibility. The results were presented in both cartographic form (isochrone approach and tabular form (cumulative approach. Research was conducted adopting different forms of transport used for relocation (including foot traffic, car, rail and multimodal transport and both the current and target layout of the transport network. This made it possible to determine the changes that will effectively run the process of investment in transport infrastructure on Polish territory. This allowed the identification of the areas of Poland which are particularly conveniently located in relation to domestic connections (in terms of the international network and those for which the European transport network remains difficult to access.

  13. FttC-Based Fronthaul for 5G Dense/Ultra-Dense Access Network: Performance and Costs in Realistic Scenarios

    Directory of Open Access Journals (Sweden)

    Franco Mazzenga

    2017-10-01

    Full Text Available One distinctive feature of the next 5G systems is the presence of a dense/ultra-dense wireless access network with a large number of access points (or nodes at short distances from each other. Dense/ultra-dense access networks allow for providing very high transmission capacity to terminals. However, the deployment of dense/ultra-dense networks is slowed down by the cost of the fiber-based infrastructure required to connect radio nodes to the central processing units and then to the core network. In this paper, we investigate the possibility for existing FttC access networks to provide fronthaul capabilities for dense/ultra-dense 5G wireless networks. The analysis is realistic in that it is carried out considering an actual access network scenario, i.e., the Italian FttC deployment. It is assumed that access nodes are connected to the Cabinets and to the corresponding distributors by a number of copper pairs. Different types of cities grouped in terms of population have been considered. Results focus on fronthaul transport capacity provided by the FttC network and have been expressed in terms of the available fronthaul bit rate per node and of the achievable coverage.

  14. How Turkish radiology residents access information related to their profession in this social media and smartphone era.

    Science.gov (United States)

    Ozutemiz, Can; Dicle, Oguz; Koremezli, Nevin

    2015-01-01

    To evaluate the frequency of mobile technology and social media usage among radiology residents and their access to professional information. A questionnaire consisting of 24 questions prepared using Google Drive was sent via e-mail to 550 radiology residents throughout the country. Of the 176 participating residents, 74 completed the survey via the internet, and 102 completed it at three different national radiology meetings. Response rates and its relationship with responses given to different questions were assessed. Hundred two male and 74 female residents participated in the survey. 141 (81.3%) residents thought that they had appropriate internet access in their department. The number of residents using a smartphone was 153 (86.9%). The android operating system (70, 45.8%) was the preferred operating system of respondants. Only 24 (15.7%) of the smartphone users thought that there were enough radiology related applications. "Radiology assistant" (18.9%), "Radiopedia" (7.8%) and "Radiographics" (7.8%) were the most utilized applications. Of the smartphone users, 87(56.9%) stated that they used cell phones in order to find radiological information, and the most used web pages were Google (165, 93.8%), Radiopaedia.org (129, 73.3%), Radiologyassistant.nl (135, 76.7%), and Pubmed (114, 64.8%). Social media usages were as follows: None (10, 5.7%), Facebook (139, 79%), Twitter (55, 31.3%), Google + (51, 29%) and YouTube (44, 25%). While smartphone usage rates among the residents were high, the use of radiology specific applications was not common. Social media usage was very common among residents.

  15. Assessment of micro-regional internal accessibility based on road network

    Science.gov (United States)

    Nie, Ting; Li, Manchun; Jiang, Zhixin; Huang, Kang

    2007-06-01

    Accessibility is an important indicator of regional land-use, social justice and quality of life. It means the convenience from one place to another in a specified kind of transportation system. Wide-region based, most of the present domestic accessibility research took the high-grade highway such as highway and railway as entirely open road, without considering the service that high-grade highway provides based on intersection and railway station. This study extended to put forward arithmetic to deal with this problem in a micro-regional study area. Taking New District, Wuxi City, Jiangsu Province as a study case, this study researched the assessment of micro-regional internal accessibility based on road network including closed road. This study provides a tool to regional economical and social decision, and introduces a new view for studying relationship between people and land-use in micro-district.

  16. Wireless and wireline service convergence in next generation optical access networks - the FP7 WISCON project

    DEFF Research Database (Denmark)

    Vegas Olmos, Juan José; Pang, Xiaodan; Lebedev, Alexander

    2014-01-01

    The next generation of information technology demands both high capacity and mobility for applications such as high speed wireless access capable of supporting broadband services. The transport of wireless and wireline signals is converging into a common telecommunication infrastructure. In this ......The next generation of information technology demands both high capacity and mobility for applications such as high speed wireless access capable of supporting broadband services. The transport of wireless and wireline signals is converging into a common telecommunication infrastructure...... radio-over-fiber (RoF) systems; this is a promising solution to implement broadband seamless wireless -wireline access networks. This project successfully concluded in autumn 2013, and is being follow up by another Marie Curie project entitled “flexible edge nodes for dynamic optical interconnection...

  17. FODA: a novel efficient multiple access protocol for highly dynamic self-organizing networks

    Science.gov (United States)

    Li, Hantao; Liu, Kai; Zhang, Jun

    2005-11-01

    Based on the concept of contention reservation for polling transmission and collision prevention strategy for collision resolution, a fair on-demand access (FODA) protocol for supporting node mobility and multihop architecture in highly dynamic self-organizing networks is proposed. In the protocol, a distributed clustering network architecture formed by self-organizing algorithm and a main idea of reserving channel resources to get polling service are adopted, so that the hidden terminal (HT) and exposed terminal (ET) problems existed in traffic transmission due to multihop architecture and wireless transmission can be eliminated completely. In addition, an improved collision prevention scheme based on binary countdown algorithm (BCA), called fair collision prevention (FCP) algorithm, is proposed to greatly eliminate unfair phenomena existed in contention access of newly active ordinary nodes and completely resolve access collisions. Finally, the performance comparison of the FODA protocol with carrier sense multiple access with collision avoidance (CSMA/CA) and polling protocols by OPNET simulation are presented. Simulation results show that the FODA protocol can overcome the disadvantages of CSMA/CA and polling protocols, and achieve higher throughput, lower average message delay and less average message dropping rate.

  18. Energy efficiency for cloud-radio access networks with imperfect channel state information

    KAUST Repository

    Al-Oquibi, Bayan

    2016-12-24

    The advent of smartphones and tablets over the past several years has resulted in a drastic increase of global carbon footprint, due to the explosive growth of data traffic. Improving energy efficiency (EE) becomes, therefore, a crucial design metric in next generation wireless systems (5G). Cloud radio access network (C-RAN), a promising 5G network architecture, provides an efficient framework for improving the EE performance, by means of coordinating the transmission across the network. This paper considers a C-RAN system formed by several clusters of remote radio heads (RRHs), each serving a predetermined set of mobile users (MUs), and assumes imperfect channel state information (CSI). The network performance becomes therefore a function of the intra-cluster and inter-cluster interference, as well as the channel estimation error. The paper optimizes the transmit power of each RRH in order to maximize the network global EE subject to MU service rate requirements and RRHs maximum power constraints. The paper proposes solving the optimization problem using a heuristic algorithm based on techniques from optimization theory via a two-stage iterative solution. Simulation results show that the proposed power allocation algorithm provides an appreciable performance improvement as compared to the conventional systems with maximum power transmission strategy. They further highlight the convergence of the proposed algorithm for different networks scenarios.

  19. The Effects of a Dynamic Spectrum Access Overlay in LTE-Advanced Networks

    Energy Technology Data Exchange (ETDEWEB)

    Juan D. Deaton; Ryan E. lrwin; Luiz A. DaSilva

    2011-05-01

    As early as 2014, wireless network operators spectral capacity will be overwhelmed by a data tsunami brought on by new devices and applications. To augment spectral capacity, operators could deploy a Dynamic Spectrum Access (DSA) overlay. In the light of the many planned Long Term Evolution (LTE) network deployments, the affects of a DSA overlay have not been fully considered into the existing LTE standards. Coalescing many different aspects of DSA, this paper develops the Spectrum Accountability (SA) framework. The SA framework defines specific network element functionality, protocol interfaces, and signaling flow diagrams for LTE to support service requests and enforce rights of responsibilities of primary and secondary users, respectively. We also include a network simulation to quantify the benefits of using DSA channels to augment capacity. Based on our simulation we show that, network operators can benefit up to %40 increase in operating capacity when sharing DSA bands to augment spectral capacity. With our framework, this paper could serve as an guide in developing future LTE network standards that include DSA.

  20. Integrating Authentic Earth Science Data in Online Visualization Tools and Social Media Networking to Promote Earth Science Education

    Science.gov (United States)

    Carter, B. L.; Campbell, B.; Chambers, L.; Davis, A.; Riebeek, H.; Ward, K.

    2008-12-01

    The Goddard Space Flight Center (GSFC) is one of the largest Earth Science research-based institutions in the nation. Along with the research comes a dedicated group of people who are tasked with developing Earth science research-based education and public outreach materials to reach the broadest possible range of audiences. The GSFC Earth science education community makes use of a wide variety of platforms in order to reach their goals of communicating science. These platforms include using social media networking such as Twitter and Facebook, as well as geo-spatial tools such as MY NASA DATA, NASA World Wind, NEO, and Google Earth. Using a wide variety of platforms serves the dual purposes of promoting NASA Earth Science research and making authentic data available to educational communities that otherwise might not otherwise be granted access. Making data available to education communities promotes scientific literacy through the investigation of scientific phenomena using the same data that is used by the scientific community. Data from several NASA missions will be used to demonstrate the ways in which Earth science data are made available for the education community.

  1. Resource allocation in heterogeneous cloud radio access networks: advances and challenges

    KAUST Repository

    Dahrouj, Hayssam

    2015-06-01

    Base station densification is increasingly used by network operators to provide better throughput and coverage performance to mobile subscribers in dense data traffic areas. Such densification is progressively diffusing the move from traditional macrocell base stations toward heterogeneous networks with diverse cell sizes (e.g., microcell, picocell, femotcell) and diverse radio access technologies (e.g., GSM, CDMA), and LTE). The coexistence of the different network entities brings an additional set of challenges, particularly in terms of the provisioning of high-speed communications and the management of wireless interference. Resource sharing between different entities, largely incompatible in conventional systems due to the lack of interconnections, becomes a necessity. By connecting all the base stations from different tiers to a central processor (referred to as the cloud) through wire/wireline backhaul links, the heterogeneous cloud radio access network, H-CRAN, provides an open, simple, controllable, and flexible paradigm for resource allocation. This article discusses challenges and recent developments in H-CRAN design. It proposes promising resource allocation schemes in H-CRAN: coordinated scheduling, hybrid backhauling, and multicloud association. Simulations results show how the proposed strategies provide appreciable performance improvement compared to methods from recent literature. © 2015 IEEE.

  2. Support networks and people with physical disabilities: social inclusion and access to health services

    Directory of Open Access Journals (Sweden)

    Cristina Marques de Almeida Holanda

    2015-01-01

    Full Text Available This study seeks to identify the formation of social support networks of people with physical disabilities, and how these networks can help facilitate access to health services and promote social inclusion. It is a cross-sectional study, with data collected via a form applied to physically disabled persons over eighteen years of age registered with the Family Health Teams of the municipal district of João Pessoa in the state of Paraíba. It was observed that the support networks of these individuals predominantly consist of family members (parents, siblings, children, spouses and people outside the family (friends and neighbors. However, 50% of the interviewees declared that they could not count on any support from outside the family. It was observed that the support network contributes to access to the services and participation in social groups. However, reduced social inclusion was detected, due to locomotion difficulties, this being the main barrier to social interaction. Among those individuals who began to interact in society, the part played by social support was fundamental.

  3. Distributed Robust Power Minimization for the Downlink of Multi-Cloud Radio Access Networks

    KAUST Repository

    Dhifallah, Oussama Najeeb

    2017-02-07

    Conventional cloud radio access networks assume single cloud processing and treat inter-cloud interference as background noise. This paper considers the downlink of a multi-cloud radio access network (CRAN) where each cloud is connected to several base-stations (BS) through limited-capacity wireline backhaul links. The set of BSs connected to each cloud, called cluster, serves a set of pre-known mobile users (MUs). The performance of the system becomes therefore a function of both inter-cloud and intra-cloud interference, as well as the compression schemes of the limited capacity backhaul links. The paper assumes independent compression scheme and imperfect channel state information (CSI) where the CSI errors belong to an ellipsoidal bounded region. The problem of interest becomes the one of minimizing the network total transmit power subject to BS power and quality of service constraints, as well as backhaul capacity and CSI error constraints. The paper suggests solving the problem using the alternating direction method of multipliers (ADMM). One of the highlight of the paper is that the proposed ADMM-based algorithm can be implemented in a distributed fashion across the multi-cloud network by allowing a limited amount of information exchange between the coupled clouds. Simulation results show that the proposed distributed algorithm provides a similar performance to the centralized algorithm in a reasonable number of iterations.

  4. Support networks and people with physical disabilities: social inclusion and access to health services.

    Science.gov (United States)

    Holanda, Cristina Marques de Almeida; De Andrade, Fabienne Louise Juvêncio Paes; Bezerra, Maria Aparecida; Nascimento, João Paulo da Silva; Neves, Robson da Fonseca; Alves, Simone Bezerra; Ribeiro, Kátia Suely Queiroz Silva

    2015-01-01

    This study seeks to identify the formation of social support networks of people with physical disabilities, and how these networks can help facilitate access to health services and promote social inclusion. It is a cross-sectional study, with data collected via a form applied to physically disabled persons over eighteen years of age registered with the Family Health Teams of the municipal district of João Pessoa in the state of Paraíba. It was observed that the support networks of these individuals predominantly consist of family members (parents, siblings, children, spouses) and people outside the family (friends and neighbors). However, 50% of the interviewees declared that they could not count on any support from outside the family. It was observed that the support network contributes to access to the services and participation in social groups. However, reduced social inclusion was detected, due to locomotion difficulties, this being the main barrier to social interaction. Among those individuals who began to interact in society, the part played by social support was fundamental.

  5. A Novel Architecture for Adaptive Traffic Control in Network on Chip using Code Division Multiple Access Technique

    OpenAIRE

    Fatemeh. Dehghani; Shahram. Darooei

    2016-01-01

    Network on chip has emerged as a long-term and effective method in Multiprocessor System-on-Chip communications in order to overcome the bottleneck in bus based communication architectures. Efficiency and performance of network on chip is so dependent on the architecture and structure of the network. In this paper a new structure and architecture for adaptive traffic control in network on chip using Code Division Multiple Access technique is presented. To solve the problem of synchronous acce...

  6. Experimental validation of a distributed algorithm for dynamic spectrum access in local area networks

    DEFF Research Database (Denmark)

    Tonelli, Oscar; Berardinelli, Gilberto; Tavares, Fernando Menezes Leitão

    2013-01-01

    activities with the Autonomous Component Carrier Selection (ACCS) algorithm, a distributed solution for interference management among small neighboring cells. A preliminary evaluation of the algorithm performance is provided considering its live execution on a software defined radio network testbed......Next generation wireless networks aim at a significant improvement of the spectral efficiency in order to meet the dramatic increase in data service demand. In local area scenarios user-deployed base stations are expected to take place, thus making the centralized planning of frequency resources...... among the cells, a non-viable solution. Cognitive Radio (CR) and Dynamic Spectrum Access (DSA) are the research paradigms which are expected to provide the network nodes the capabilities for an autonomous and efficient selection of the spectrum resources. In this paper we present the first experimental...

  7. On the Evaluation of a Secure Solution to Access 802.11 Networks

    Science.gov (United States)

    da Costa, Fernando; Gaspary, Luciano; Barbosa, Jorge; Cavalheiro, Gerson; Pfitscher, Luciano; Ramos, José Dirceu G.

    Despite offering the possibility to develop and distribute a new set of applications to its users, the widespread and unrestricted use of mobile computing depends on the provisioning of a secure network environment. Regarding the communication established from mobile devices such as PDAs (Personal Digital Assistants), one of the most currently used standards is the IEEE 802.11b, which presents known security flaws. To overcome them, some alternative setups are commonly deployed, based on link, network, transport or application-layer. In this paper we evaluate the impact on data reception rate and energy consumption of IPSec-based PDAs access to 802.11b (WiFi) wireless LANs. As a result of this work we identify the overhead imposed by the security mechanisms and the capacity of the device to run CPU and network-intensive applications.

  8. Statistics of the uplink co-tier interference in closed access heterogeneous networks

    KAUST Repository

    Tabassum, Hina

    2013-09-01

    In this paper, we derive a statistical model of the co-tier interference in closed access two tier heterogeneous wireless cellular networks with femtocell deployments. The derived model captures the impact of bounded path loss model, wall penetration loss, user distributions, random locations, and density of the femtocells. Firstly, we derive the analytical expressions for the probability density function (PDF) and moment generating function (MGF) of the co-tier interference considering a single femtocell interferer by exploiting the random disc line picking theory from geometric probability. We then derive the MGF of the cumulative interference from all femtocell interferers considering full spectral reuse in each femtocell. Orthogonal spectrum partitioning is assumed between the macrocell and femtocell networks to avoid any cross-tier interference. Finally, the accuracy of the derived expressions is validated through Monte-Carlo simulations and the expressions are shown to be useful in quantifying important network performance metrics such as ergodic capacity. © 2013 IEEE.

  9. FttC-Based Fronthaul for 5G Dense/Ultra-Dense Access Network: Performance and Costs in Realistic Scenarios

    OpenAIRE

    Franco Mazzenga; Romeo Giuliano; Francesco Vatalaro

    2017-01-01

    One distinctive feature of the next 5G systems is the presence of a dense/ultra-dense wireless access network with a large number of access points (or nodes) at short distances from each other. Dense/ultra-dense access networks allow for providing very high transmission capacity to terminals. However, the deployment of dense/ultra-dense networks is slowed down by the cost of the fiber-based infrastructure required to connect radio nodes to the central processing units and then to the core net...

  10. Domain decomposition approach to extract pore-network models from large 3D porous media images

    Science.gov (United States)

    Timofey, Sizonenko; Marina, Karsanina; Irina, Bayuk; Kirill, Gerke

    2017-04-01

    Pore-network are very useful and effective method to model porous media structure and properties such as permeability and multi-phase flow. Several methods for pore-network extraction were proposed to date, including median axis, maximal inscribed ball, watershed techniques and their modifications. Input data for pore-network extraction algorithms usually represent 3D binary image. Modern X-ray tomography devices can easily provide scans with dimensions of 4k x 4k x 10k voxels. For such large images extraction algorithms may hit the problem of memory (RAM) consumption or will too time consuming. To overcome such problems or create parallelizable algorithm here we propose to divide the whole volume into sub-volumes with smaller size and extract pore- network sequentially/in parallel manner separately. However, the problem of correct pore-network extraction at the sub-volume connection areas is challenging. In this contribution we address this issue in detail. We propose a method to merge such sub-volumes. Our method explores the slices of porous medium under study at the sub-volumes intersections. Each slice has its own geometric features and associated with a number of pores or throats. Characteristics of pore that associated with slice such as diameter, distance its center to the sub-domain boundary are also taken into account. Based on the pore element properties and also properties of aforementioned slices the algorithm makes decision about how pores from opposite sides of sub-volumes should be connected. There are 3 cases of merging: 1) building a throat between pores, 2) absorption of one pore by the other, 3) breaking connection (no pore or throat are built). We have tested our approach on several different binary 3D images, including soil, sandstones, and carbonates. We also compared this new approach against a conventional one where the extraction is performed using the whole domain without its decomposition into sub-domains. We show that our approach

  11. Advanced digital signal processing for short-haul and access network

    Science.gov (United States)

    Zhang, Junwen; Yu, Jianjun; Chi, Nan

    2016-02-01

    Digital signal processing (DSP) has been proved to be a successful technology recently in high speed and high spectrum-efficiency optical short-haul and access network, which enables high performances based on digital equalizations and compensations. In this paper, we investigate advanced DSP at the transmitter and receiver side for signal pre-equalization and post-equalization in an optical access network. A novel DSP-based digital and optical pre-equalization scheme has been proposed for bandwidth-limited high speed short-distance communication system, which is based on the feedback of receiver-side adaptive equalizers, such as least-mean-squares (LMS) algorithm and constant or multi-modulus algorithms (CMA, MMA). Based on this scheme, we experimentally demonstrate 400GE on a single optical carrier based on the highest ETDM 120-GBaud PDM-PAM-4 signal, using one external modulator and coherent detection. A line rate of 480-Gb/s is achieved, which enables 20% forward-error correction (FEC) overhead to keep the 400-Gb/s net information rate. The performance after fiber transmission shows large margin for both short range and metro/regional networks. We also extend the advanced DSP for short haul optical access networks by using high order QAMs. We propose and demonstrate a high speed multi-band CAP-WDM-PON system on intensity modulation, direct detection and digital equalizations. A hybrid modified cascaded MMA post-equalization schemes are used to equalize the multi-band CAP-mQAM signals. Using this scheme, we successfully demonstrates 550Gb/s high capacity WDMPON system with 11 WDM channels, 55 sub-bands, and 10-Gb/s per user in the downstream over 40-km SMF.

  12. Basset: learning the regulatory code of the accessible genome with deep convolutional neural networks.

    Science.gov (United States)

    Kelley, David R; Snoek, Jasper; Rinn, John L

    2016-07-01

    The complex language of eukaryotic gene expression remains incompletely understood. Despite the importance suggested by many noncoding variants statistically associated with human disease, nearly all such variants have unknown mechanisms. Here, we address this challenge using an approach based on a recent machine learning advance-deep convolutional neural networks (CNNs). We introduce the open source package Basset to apply CNNs to learn the functional activity of DNA sequences from genomics data. We trained Basset on a compendium of accessible genomic sites mapped in 164 cell types by DNase-seq, and demonstrate greater predictive accuracy than previous methods. Basset predictions for the change in accessibility between variant alleles were far greater for Genome-wide association study (GWAS) SNPs that are likely to be causal relative to nearby SNPs in linkage disequilibrium with them. With Basset, a researcher can perform a single sequencing assay in their cell type of interest and simultaneously learn that cell's chromatin accessibility code and annotate every mutation in the genome with its influence on present accessibility and latent potential for accessibility. Thus, Basset offers a powerful computational approach to annotate and interpret the noncoding genome. © 2016 Kelley et al.; Published by Cold Spring Harbor Laboratory Press.

  13. The task-dependent effect of tags and ratings on social media access

    NARCIS (Netherlands)

    M. Clements (Maarten); A.P. de Vries (Arjen); M.J.T. Reinders

    2010-01-01

    htmlabstractRecently, online social networks have emerged that allow people to share their multimedia files, retrieve interesting content, and discover like-minded people. These systems often provide the possibility to annotate the content with tags and ratings. Using a random walk through the

  14. Adaptation of AMO-FBMC-OQAM in optical access network for accommodating asynchronous multiple access in OFDM-based uplink transmission

    Science.gov (United States)

    Jung, Sun-Young; Jung, Sang-Min; Han, Sang-Kook

    2015-01-01

    Exponentially expanding various applications in company with proliferation of mobile devices make mobile traffic exploded annually. For future access network, bandwidth efficient and asynchronous signals converged transmission technique is required in optical network to meet a huge bandwidth demand, while integrating various services and satisfying multiple access in perceived network resource. Orthogonal frequency division multiplexing (OFDM) is highly bandwidth efficient parallel transmission technique based on orthogonal subcarriers. OFDM has been widely studied in wired-/wireless communication and became a Long term evolution (LTE) standard. Consequently, OFDM also has been actively researched in optical network. However, OFDM is vulnerable frequency and phase offset essentially because of its sinc-shaped side lobes, therefore tight synchronism is necessary to maintain orthogonality. Moreover, redundant cyclic prefix (CP) is required in dispersive channel. Additionally, side lobes act as interference among users in multiple access. Thus, it practically hinders from supporting integration of various services and multiple access based on OFDM optical transmission In this paper, adaptively modulated optical filter bank multicarrier system with offset QAM (AMO-FBMC-OQAM) is introduced and experimentally investigated in uplink optical transmission to relax multiple access interference (MAI), while improving bandwidth efficiency. Side lobes are effectively suppressed by using FBMC, therefore the system becomes robust to path difference and imbalance among optical network units (ONUs), which increase bandwidth efficiency by reducing redundancy. In comparison with OFDM, a signal performance and an efficiency of frequency utilization are improved in the same experimental condition. It enables optical network to effectively support heterogeneous services and multiple access.

  15. Decentralized Group Sparse Beamforming for Multi-Cloud Radio Access Networks

    KAUST Repository

    Dhifallah, Oussama Najeeb

    2015-12-06

    Recent studies on cloud-radio access networks (CRANs) assume the availability of a single processor (cloud) capable of managing the entire network performance; inter-cloud interference is treated as background noise. This paper considers the more practical scenario of the downlink of a CRAN formed by multiple clouds, where each cloud is connected to a cluster of multiple-antenna base stations (BSs) via high-capacity wireline backhaul links. The network is composed of several disjoint BSs\\' clusters, each serving a pre-known set of single-antenna users. To account for both inter- cloud and intra-cloud interference, the paper considers the problem of minimizing the total network power consumption subject to quality of service constraints, by jointly determining the set of active BSs connected to each cloud and the beamforming vectors of every user across the network. The paper solves the problem using Lagrangian duality theory through a dual decomposition approach, which decouples the problem into multiple and independent subproblems, the solution of which depends on the dual optimization problem. The solution then proceeds in updating the dual variables and the active set of BSs at each cloud iteratively. The proposed approach leads to a distributed implementation across the multiple clouds through a reasonable exchange of information between adjacent clouds. The paper further proposes a centralized solution to the problem. Simulation results suggest that the proposed algorithms significantly outperform the conventional per-cloud update solution, especially at high signal-to-interference-plus- noise ratio (SINR) target.

  16. Stochastic geometry model for multi-channel fog radio access networks

    KAUST Repository

    Emara, Mostafa

    2017-06-29

    Cache-enabled base station (BS) densification, denoted as a fog radio access network (F-RAN), is foreseen as a key component of 5G cellular networks. F-RAN enables storing popular files at the network edge (i.e., BS caches), which empowers local communication and alleviates traffic congestions at the core/backhaul network. The hitting probability, which is the probability of successfully transmitting popular files request from the network edge, is a fundamental key performance indicator (KPI) for F-RAN. This paper develops a scheduling aware mathematical framework, based on stochastic geometry, to characterize the hitting probability of F-RAN in a multi-channel environment. To this end, we assess and compare the performance of two caching distribution schemes, namely, uniform caching and Zipf caching. The numerical results show that the commonly used single channel environment leads to pessimistic assessment for the hitting probability of F-RAN. Furthermore, the numerical results manifest the superiority of the Zipf caching scheme and quantify the hitting probability gains in terms of the number of channels and cache size.

  17. Medium Access Control Protocols for Wireless Sensor Networks with Energy Harvesting

    CERN Document Server

    Iannello, Fabio; Spagnolini, Umberto

    2011-01-01

    The design of Medium Access Control (MAC) protocols for wireless sensor networks (WSNs) has been conventionally tackled by assuming battery-powered devices and by adopting the network lifetime as the main performance criterion. While WSNs operated by energy-harvesting (EH) devices are not limited by network lifetime, they pose new design challenges due to the uncertain amount of harvestable energy. Novel design criteria are thus required to capture the trade-offs between the potentially infinite network lifetime and the uncertain energy availability. This paper addresses the analysis and design of WSNs with EH devices by focusing on conventional MAC protocols, namely TDMA, Framed-ALOHA (FA) and Dynamic-FA (DFA), and by accounting for the performance trade-offs and design issues arising due to EH. A novel metric, referred to as delivery probability, is introduced to measure the capability of a MAC protocol to deliver the measure of any sensor in the network to the intended destination (or fusion center, FC). T...

  18. An Effective Massive Sensor Network Data Access Scheme Based on Topology Control for the Internet of Things.

    Science.gov (United States)

    Yi, Meng; Chen, Qingkui; Xiong, Neal N

    2016-11-03

    This paper considers the distributed access and control problem of massive wireless sensor networks' data access center for the Internet of Things, which is an extension of wireless sensor networks and an element of its topology structure. In the context of the arrival of massive service access requests at a virtual data center, this paper designs a massive sensing data access and control mechanism to improve the access efficiency of service requests and makes full use of the available resources at the data access center for the Internet of things. Firstly, this paper proposes a synergistically distributed buffer access model, which separates the information of resource and location. Secondly, the paper divides the service access requests into multiple virtual groups based on their characteristics and locations using an optimized self-organizing feature map neural network. Furthermore, this paper designs an optimal scheduling algorithm of group migration based on the combination scheme between the artificial bee colony algorithm and chaos searching theory. Finally, the experimental results demonstrate that this mechanism outperforms the existing schemes in terms of enhancing the accessibility of service requests effectively, reducing network delay, and has higher load balancing capacity and higher resource utility rate.

  19. Exposure Research Going Mobile: A Smartphone-Based Measurement of Media Exposure to Political Information in a Convergent Media Environment

    DEFF Research Database (Denmark)

    Ohme, J.; Albaek, E.; H. de Vreese, C.

    2016-01-01

    platform modes. The study furthermore confirms limitations of mere usage time measurements of social media platforms in effects research and explores a range of actual content types that citizens encounter in social networks. It recommends more frequent use of mobile exposure measurements and argues......In today’s convergent media environment, media exposure becomes increasingly channel-independent and social media-bound, and media content is more frequently accessed on mobile devices. This calls for new approaches to measuring media exposure. This study applies an innovative approach to survey (n...... for a content-related assessment of social media use in effects research. © 2016 Taylor & Francis....

  20. A Novel Approach for Transmission of 56 Gbit/s NRZ Signal in Access Network Using Spectrum Slicing Technique

    DEFF Research Database (Denmark)

    Spolitis, S.; Vegas Olmos, Juan José; Bobrovs, V.

    2013-01-01

    We present the spectrum slicing and stitching concept for high-capacity low optics complexity optical access networks. Spectrum slicing and stitching of a 56 Gbit/s NRZ electrical signal is experimentally demonstrated for the first time....

  1. SOCIAL NETWORKING AND ITS IMPACT ON STUDENT PERFORMANCE: MEDIA COLLAGE IN THI-QAR AS A CASE STUDY

    OpenAIRE

    Wisam Abduladheem Kamil*

    2017-01-01

    There may be no doubt that Social networking has gained wider acceptability and usefulness and is also becoming possibly the most important communication tools amongst college students particularly at the higher stage of instructional pursuit. Whilst, to up-date in the Arab countries used social media only protest and indignation of services. There are many studies has focused on the benefits of the social networking tools in educational institutions. Unfortunately, most of these studies cond...

  2. Businesswomen, dabblers, revivalists or conmen? : representation of selling and salespeople within academic, network marketing practitioner and media discourses

    OpenAIRE

    Oksanen-Ylikoski, Elina

    2006-01-01

    Representation of selling and salespeople within academic, network marketing practitioner and media discourses In this study, my purpose is to explore conflicting representations of selling and especially network marketing (NM). My first objective is to identify the fundamental features of sales discourses within academic and practitioner communities. The second objective is to understand in what ways the combination and contestation of these discourses produce ambiguous images of selling and...

  3. Social networking addiction, attachment style, and validation of the Italian version of the Bergen Social Media Addiction Scale

    OpenAIRE

    Monacis, Lucia; de Palo, Valeria; Griffiths, Mark D.; Sinatra, Maria

    2017-01-01

    Aim: Research into social networking addiction has greatly increased over the last decade. However, the number of\\ud validated instruments assessing addiction to social networking sites (SNSs) remains few, and none have been\\ud validated in the Italian language. Consequently, this study tested the psychometric properties of the Italian version of\\ud the Bergen Social Media Addiction Scale (BSMAS), as well as providing empirical data concerning the relationship\\ud between attachment styles and...

  4. Medium Access Control Protocols for Cognitive Radio Ad Hoc Networks: A Survey.

    Science.gov (United States)

    Zareei, Mahdi; Islam, A K M Muzahidul; Baharun, Sabariah; Vargas-Rosales, Cesar; Azpilicueta, Leyre; Mansoor, Nafees

    2017-09-16

    New wireless network paradigms will demand higher spectrum use and availability to cope with emerging data-hungry devices. Traditional static spectrum allocation policies cause spectrum scarcity, and new paradigms such as Cognitive Radio (CR) and new protocols and techniques need to be developed in order to have efficient spectrum usage. Medium Access Control (MAC) protocols are accountable for recognizing free spectrum, scheduling available resources and coordinating the coexistence of heterogeneous systems and users. This paper provides an ample review of the state-of-the-art MAC protocols, which mainly focuses on Cognitive Radio Ad Hoc Networks (CRAHN). First, a description of the cognitive radio fundamental functions is presented. Next, MAC protocols are divided into three groups, which are based on their channel access mechanism, namely time-slotted protocol, random access protocol and hybrid protocol. In each group, a detailed and comprehensive explanation of the latest MAC protocols is presented, as well as the pros and cons of each protocol. A discussion on future challenges for CRAHN MAC protocols is included with a comparison of the protocols from a functional perspective.

  5. An Optimal Medium Access Control with Partial Observations for Sensor Networks

    Directory of Open Access Journals (Sweden)

    Servetto Sergio D

    2005-01-01

    Full Text Available We consider medium access control (MAC in multihop sensor networks, where only partial information about the shared medium is available to the transmitter. We model our setting as a queuing problem in which the service rate of a queue is a function of a partially observed Markov chain representing the available bandwidth, and in which the arrivals are controlled based on the partial observations so as to keep the system in a desirable mildly unstable regime. The optimal controller for this problem satisfies a separation property: we first compute a probability measure on the state space of the chain, namely the information state, then use this measure as the new state on which the control decisions are based. We give a formal description of the system considered and of its dynamics, we formalize and solve an optimal control problem, and we show numerical simulations to illustrate with concrete examples properties of the optimal control law. We show how the ergodic behavior of our queuing model is characterized by an invariant measure over all possible information states, and we construct that measure. Our results can be specifically applied for designing efficient and stable algorithms for medium access control in multiple-accessed systems, in particular for sensor networks.

  6. Medium Access Control Protocols for Cognitive Radio Ad Hoc Networks: A Survey

    Science.gov (United States)

    Islam, A. K. M. Muzahidul; Baharun, Sabariah; Mansoor, Nafees

    2017-01-01

    New wireless network paradigms will demand higher spectrum use and availability to cope with emerging data-hungry devices. Traditional static spectrum allocation policies cause spectrum scarcity, and new paradigms such as Cognitive Radio (CR) and new protocols and techniques need to be developed in order to have efficient spectrum usage. Medium Access Control (MAC) protocols are accountable for recognizing free spectrum, scheduling available resources and coordinating the coexistence of heterogeneous systems and users. This paper provides an ample review of the state-of-the-art MAC protocols, which mainly focuses on Cognitive Radio Ad Hoc Networks (CRAHN). First, a description of the cognitive radio fundamental functions is presented. Next, MAC protocols are divided into three groups, which are based on their channel access mechanism, namely time-slotted protocol, random access protocol and hybrid protocol. In each group, a detailed and comprehensive explanation of the latest MAC protocols is presented, as well as the pros and cons of each protocol. A discussion on future challenges for CRAHN MAC protocols is included with a comparison of the protocols from a functional perspective. PMID:28926952

  7. Social Media-Based Collaborative Information Access: Analysis of Online Crisis-Related Twitter Conversations

    OpenAIRE

    Roth, Camille

    2016-01-01

    The notion of implicit (or explicit) collaborative information access refers to systems and practices allowing a group of users to unintentionally (respectively intentionally) seek, share and retrieve information to achieve similar (respectively shared) information-related goals. Despite an increasing adoption in social environments, collaboration behavior in information seeking and retrieval is mainly limited to small-sized groups, generally restricted to working spaces. Much remains to be l...

  8. Introduction to focus issue: Synchronization in large networks and continuous media-data, models, and supermodels.

    Science.gov (United States)

    Duane, Gregory S; Grabow, Carsten; Selten, Frank; Ghil, Michael

    2017-12-01

    The synchronization of loosely coupled chaotic systems has increasingly found applications to large networks of differential equations and to models of continuous media. These applications are at the core of the present Focus Issue. Synchronization between a system and its model, based on limited observations, gives a new perspective on data assimilation. Synchronization among different models of the same system defines a supermodel that can achieve partial consensus among models that otherwise disagree in several respects. Finally, novel methods of time series analysis permit a better description of synchronization in a system that is only observed partially and for a relatively short time. This Focus Issue discusses synchronization in extended systems or in components thereof, with particular attention to data assimilation, supermodeling, and their applications to various areas, from climate modeling to macroeconomics.

  9. Utilizing neural networks in magnetic media modeling and field computation: A review.

    Science.gov (United States)

    Adly, Amr A; Abd-El-Hafiz, Salwa K

    2014-11-01

    Magnetic materials are considered as crucial components for a wide range of products and devices. Usually, complexity of such materials is defined by their permeability classification and coupling extent to non-magnetic properties. Hence, development of models that could accurately simulate the complex nature of these materials becomes crucial to the multi-dimensional field-media interactions and computations. In the past few decades, artificial neural networks (ANNs) have been utilized in many applications to perform miscellaneous tasks such as identification, approximation, optimization, classification and forecasting. The purpose of this review article is to give an account of the utilization of ANNs in modeling as well as field computation involving complex magnetic materials. Mostly used ANN types in magnetics, advantages of this usage, detailed implementation methodologies as well as numerical examples are given in the paper.

  10. Utilizing neural networks in magnetic media modeling and field computation: A review

    Directory of Open Access Journals (Sweden)

    Amr A. Adly

    2014-11-01

    Full Text Available Magnetic materials are considered as crucial components for a wide range of products and devices. Usually, complexity of such materials is defined by their permeability classification and coupling extent to non-magnetic properties. Hence, development of models that could accurately simulate the complex nature of these materials becomes crucial to the multi-dimensional field-media interactions and computations. In the past few decades, artificial neural networks (ANNs have been utilized in many applications to perform miscellaneous tasks such as identification, approximation, optimization, classification and forecasting. The purpose of this review article is to give an account of the utilization of ANNs in modeling as well as field computation involving complex magnetic materials. Mostly used ANN types in magnetics, advantages of this usage, detailed implementation methodologies as well as numerical examples are given in the paper.

  11. Impact of Users Identities and Access Conditions on Downlink Performance in Closed Small-Cell Networks

    KAUST Repository

    Radaydeh, Redha

    2015-05-26

    This paper investigates the effect of various operation parameters on the downlink user performance in overlaid small-cell networks. The case study considers closed-access small cells (e.g., femtocells), wherein only active authorized user equipments (UEs) can be served, and each of which is allocated single downlink channel at a time. On the other hand, the macrocell base station can unconditionally serve macrocell UEs that exist inside its coverage space. The available channels can be shared simultaneously in the macrocell network and the femtocell network. Moreover, a channel can be reused only at the macrocell base station. The analysis provides quantitative approaches to model UEs identities, their likelihoods of being active, and their likelihoods of producing interference, considering UEs classifications, locations, and access capabilities. Moreover, it develops models for various interference sources observed from effective interference femtocells, considering femtocells capacities and operation conditions. The associated formulations to describe a desired UE performance and the impact of the number of available channels as well as the adopted channel assignment approach are thoroughly investigated. The results are generally presented for any channel models of interference sources as well as the desired source of the served UE. Moreover, specific channel models are then adopted, for which generalized closedform analytical results for the desired UE outage probability performance are obtained. Numerical and simulation results are presented to further clarify the main outcomes of the developed analysis.

  12. Hybrid Access Femtocells in Overlaid MIMO Cellular Networks with Transmit Selection under Poisson Field Interference

    KAUST Repository

    Abdel Nabi, Amr A

    2017-09-21

    This paper analyzes the performance of hybrid control-access schemes for small cells (such as femtocells) in the context of two-tier overlaid cellular networks. The proposed hybrid access schemes allow for sharing the same downlink resources between the small-cell network and the original macrocell network, and their mode of operations are characterized considering post-processed signal-to-interference-plus-noise ratios (SINRs) or pre-processed interference-aware operation. The work presents a detailed treatment of achieved performance of a desired user that benefits from MIMO arrays configuration through the use of transmit antenna selection (TAS) and maximal ratio combining (MRC) in the presence of Poisson field interference processes on spatial links. Furthermore, based on the interference awareness at the desired user, two TAS approaches are treated, which are the signal-to-noise (SNR)-based selection and SINR-based selection. The analysis is generalized to address the cases of highly-correlated and un-correlated aggregated interference on different transmit channels. In addition, the effect of delayed TAS due to imperfect feedback and the impact of arbitrary TAS processing are investigated. The analytical results are validated by simulations, to clarify some of the main outcomes herein.

  13. Network governance for dealing with IT-enabled Interorganizational cooperation : When should network IT - such as social media - be used and how to govern it

    NARCIS (Netherlands)

    Dr. Hugo Velthuijsen; F.J. de Graaf

    2012-01-01

    IT-based networking trends such as the rise of social media, crowd sourcing, open innovation, and cloud computing enable a profoundly different way of working and collaborating that challenges significantly traditional approaches of companies towards governance, i.e. the mechanisms a company

  14. Pore network modeling of the electrical signature of solute transport in dual-domain media

    Science.gov (United States)

    Day-Lewis, F. D.; Linde, N.; Haggerty, R.; Singha, K.; Briggs, M. A.

    2017-05-01

    Dual-domain models are used to explain anomalous solute transport behavior observed in diverse hydrologic settings and applications, from groundwater remediation to hyporheic exchange. To constrain such models, new methods are needed with sensitivity to both immobile and mobile domains. Recent experiments indicate that dual-domain transport of ionic tracers has an observable geoelectrical signature, appearing as a nonlinear, hysteretic relation between paired bulk and fluid electrical conductivity. Here we present a mechanistic explanation for this geoelectrical signature and evaluate assumptions underlying a previously published petrophysical model for bulk conductivity in dual-domain media. Pore network modeling of fluid flow, solute transport, and electrical conduction (1) verifies the geoelectrical signature of dual-domain transport, (2) reveals limitations of the previously used petrophysical model, and (3) demonstrates that a new petrophysical model, based on differential effective media theory, closely approximates the simulated bulk/fluid conductivity relation. These findings underscore the potential of geophysically based calibration of dual-domain models.

  15. Reactive transport in porous media: Pore-network model approach compared to pore-scale model

    Science.gov (United States)

    Varloteaux, Clément; Vu, Minh Tan; Békri, Samir; Adler, Pierre M.

    2013-02-01

    Accurate determination of three macroscopic parameters governing reactive transport in porous media, namely, the apparent solute velocity, the dispersion, and the apparent reaction rate, is of key importance for predicting solute migration through reservoir aquifers. Two methods are proposed to calculate these parameters as functions of the Péclet and the Péclet-Dahmköhler numbers. In the first method called the pore-scale model (PSM), the porous medium is discretized by the level set method; the Stokes and convection-diffusion equations with reaction at the wall are solved by a finite-difference scheme. In the second method, called the pore-network model (PNM), the void space of the porous medium is represented by an idealized geometry of pore bodies joined by pore throats; the flow field is computed by solving Kirchhoff's laws and transport calculations are performed in the asymptotic regime where the solute concentration undergoes an exponential evolution with time. Two synthetic geometries of porous media are addressed by using both numerical codes. The first geometry is constructed in order to validate the hypotheses implemented in PNM. PSM is also used for a better understanding of the various reaction patterns observed in the asymptotic regime. Despite the PNM approximations, a very good agreement between the models is obtained, which shows that PNM is an accurate description of reactive transport. PNM, which can address much larger pore volumes than PSM, is used to evaluate the influence of the concentration distribution on macroscopic properties of a large irregular network reconstructed from microtomography images. The role of the dimensionless numbers and of the location and size of the largest pore bodies is highlighted.

  16. Optimization of the matrices structural parameters for the synthesis of restricted access media (RAM) adsorbents for chromatography

    Science.gov (United States)

    Bogoslovskii, S. Yu; Echeistov, V. V.; Boldyrev, V. S.

    2017-11-01

    The geometric parameters of a matrix for the synthesis of restricted access media adsorbents are optimized, using mathematical modeling based on the basis of a globular model with tetrahedral and octahedral pores. For calculations were used the distribution curves of pore sizes obtained on the basis of the desorption branches of isotherms obtained via low temperature nitrogen adsorption. In contrast to the model of cylindrical pores, the calculation model of globular pores gives realistic values of the surface area of the silica with grafted hexadecylsilyl groups, due to the change of ratio of the amounts of tetrahedral and octahedral pores in the model. The obtained value of the surface area of the silica with grafted hexadecylsilyl groups is in good agreement with elemental analysis data. The obtained refined size of the mouth of the pores makes it possible to choose correctly the particle diameter of the external protective coating.

  17. The role of individual-media relationship and consumer personal factors on spanish teenagers´ mobile social networking sites usage

    OpenAIRE

    Ruiz Mafé, Carla; Sanz Blas, Silvia; MARTÍ PARREÑO, JOSÉ

    2014-01-01

    Social Networking Sites (SNS) are gaining momentum as powerful tools of marketing communications. Mobile phones are becoming one of the most popular devices for accessing Social Networking Sites. In Spain, 44% of Social Networking Sites users access these sites on a daily basis while 79% of them access these sites on a weekly basis. Furthermore, it is notable that over 70% of Social Networking Sites users talk about and recommend commercial brands. This justifies the interest of the study of ...

  18. Social Media as Avenue for Personal Learning for Educators: Personal Learning Networks Encourage Application of Knowledge and Skills

    Science.gov (United States)

    Eller, Linda S.

    2012-01-01

    Social media sites furnish an online space for a community of practice to create relationships and trust, collaboration and connections, and a personal learning environment. Social networking sites, both public and private, have common elements: member profiles, groups, discussions, and forums. A community of practice brings participants together…

  19. Association of School Social Networks' Influence and Mass Media Factors with Cigarette Smoking among Asthmatic Students

    Science.gov (United States)

    Kanamori, Mariano; Beck, Kenneth H.; Carter-Pokras, Olivia

    2015-01-01

    Background: Around 10% of adolescent students under 18 years have current asthma. Asthmatic adolescents smoke as much or more than non-asthmatic adolescents. We explored the association between exposure to mass media and social networks' influence with asthmatic student smoking, and variations of these exposures by sex. Methods: This study…

  20. Consequences of media and Internet use for offline and online network capital and well-being: A causal model approach

    NARCIS (Netherlands)

    Vergeer, M.R.M.; Pelzer, B.J.

    2009-01-01

    This study sets out to identify relations between people's media use, network capital as a resource, and loneliness. Unlike many studies on this topic, this study aimed to test hypotheses on a national sample, and used insights from empirical research and theoretical notions from different research