Sample records for radio network collaborative

  1. Multi-Beam Radio Frequency (RF) Aperture Arrays Using Multiplierless Approximate Fast Fourier Transform (FFT)

    DTIC Science & Technology

    2017-08-01

    filtering, correlation and radio- astronomy . In this report approximate transforms that closely follow the DFT have been studied and found. The approximate...communications, data networks, sensor networks, cognitive radio, radar and beamforming, imaging, filtering, correlation and radio- astronomy . FFTs efficiently...public release; distribution is unlimited. 4.3 Digital Hardware and Design Architectures Collaboration for Astronomy Signal Processing and Electronics

  2. Securing Collaborative Spectrum Sensing against Untrustworthy Secondary Users in Cognitive Radio Networks

    NASA Astrophysics Data System (ADS)

    Wang, Wenkai; Li, Husheng; Sun, Yan(Lindsay); Han, Zhu

    2009-12-01

    Cognitive radio is a revolutionary paradigm to migrate the spectrum scarcity problem in wireless networks. In cognitive radio networks, collaborative spectrum sensing is considered as an effective method to improve the performance of primary user detection. For current collaborative spectrum sensing schemes, secondary users are usually assumed to report their sensing information honestly. However, compromised nodes can send false sensing information to mislead the system. In this paper, we study the detection of untrustworthy secondary users in cognitive radio networks. We first analyze the case when there is only one compromised node in collaborative spectrum sensing schemes. Then we investigate the scenario that there are multiple compromised nodes. Defense schemes are proposed to detect malicious nodes according to their reporting histories. We calculate the suspicious level of all nodes based on their reports. The reports from nodes with high suspicious levels will be excluded in decision-making. Compared with existing defense methods, the proposed scheme can effectively differentiate malicious nodes and honest nodes. As a result, it can significantly improve the performance of collaborative sensing. For example, when there are 10 secondary users, with the primary user detection rate being equal to 0.99, one malicious user can make the false alarm rate [InlineEquation not available: see fulltext.] increase to 72%. The proposed scheme can reduce it to 5%. Two malicious users can make [InlineEquation not available: see fulltext.] increase to 85% and the proposed scheme reduces it to 8%.

  3. Training School Pupils in the Scientific Method: Student Participation in an International VLF Radio Experiment

    ERIC Educational Resources Information Center

    Denton, J. J.; Denton, M. H.; Kavanagh, A. J.; Harron, H.; Ulich, T.; Denton, J. S.

    2012-01-01

    We report on a school-university collaboration to involve students in the deployment, testing, and operation of a very low frequency (VLF) radio receiver as part of an international network of such experiments. A background to the collaboration is presented, along with a summary of planning and development, and the ultimate deployment of the…

  4. ERCMExpress. Volume 2, Issue 4

    ERIC Educational Resources Information Center

    US Department of Education, 2006

    2006-01-01

    This issue of ERCMExpress alerts readers of the All-Hazard NOAA weather radio (NWR) network upgrade. In 2004, The National Oceanic and Atmospheric Administration NOAA and the U.S. Department of Homeland Security (DHS) collaborated to enable DHS to disseminate homeland security-related information over the NWR network. DHS's goal was to produce an…

  5. All Over the World: Mid-Twentieth Century Radio Astronomy and the Origin of the International SETI Network

    NASA Astrophysics Data System (ADS)

    Charbonneau, Rebecca

    2018-01-01

    Cold War mythology is rife with stories about secrecy, competition, espionage, and animosity. Yet the history behind the myth-- the overlooked scientists collaborating outside of the aims of the state-- also tells an interesting story. This paper examines the challenges of international scientific collaboration during the Cold War, focusing especially on a case study concerning Soviet radio astronomer Iosif Samuilovich Shklovskii and U.S. astrophysicist Carl Sagan, and their collaborative work on the search for extraterrestrial intelligence (SETI). Despite the hyper-politics that instigated and fueled the Space Race, SETI was held up as an ideal internationalist science, with the lofty goal of uniting all of humanity by situating it within a cosmic community. Although the internationalism of SETI discourse is not entirely unfounded due to its roots in international collaboration, further research indicates that such internationalism was in reality instilled with geopolitics, international conflict, and even espionage. That said, however, the cultural and philosophical perspectives of individual SETI scientists led them to operate within the tensions between national and ideological restraints and their own personal philosophical perspectives. In reviewing the letters of correspondence, conference proceedings, interviews, transcripts of lectures, and autobiographical writings of early-SETI radio astronomers, this paper ultimately argues that, although SETI was not the ideal internationalist science it was portrayed as, SETI pioneers were able to connect and form international networks within a contentious system which often centred on the restriction of free information and international collaboration through their mutual unconventional scientific interests, and facilitated by their personal utopian futurist philosophies.

  6. mDARAL: A Multi-Radio Version for the DARAL Routing Algorithm.

    PubMed

    Estévez, Francisco José; Castillo-Secilla, José María; González, Jesús; Olivares, Joaquín; Glösekötter, Peter

    2017-02-09

    Smart Cities are called to change the daily life of human beings. This concept permits improving the efficiency of our cities in several areas such as the use of water, energy consumption, waste treatment, and mobility both for people as well as vehicles throughout the city. This represents an interconnected scenario in which thousands of embedded devices need to work in a collaborative way both for sensing and modifying the environment properly. Under this scenario, the majority of devices will use wireless protocols for communicating among them, representing a challenge for optimizing the use of the electromagnetic spectrum. When the density of deployed nodes increases, the competition for using the physical medium becomes harder and, in consequence, traffic collisions will be higher, affecting data-rates in the communication process. This work presents mDARAL , a multi-radio routing algorithm based on the Dynamic and Adaptive Radio Algorithm ( DARAL ), which has the capability of isolating groups of nodes into sub-networks. The nodes of each sub-network will communicate among them using a dedicated radio frequency, thus isolating the use of the radio channel to a reduced number of nodes. Each sub-network will have a master node with two physical radios, one for communicating with its neighbours and the other for being the contact point among its group and other sub-networks. The communication among sub-networks is done through master nodes in a dedicated radio frequency. The algorithm works to maximize the overall performance of the network through the distribution of the traffic messages into unoccupied frequencies. The obtained results show that mDARAL achieves great improvement in terms of the number of control messages necessary to connect a node to the network, convergence time and energy consumption during the connection phase compared to DARAL .

  7. mDARAL: A Multi-Radio Version for the DARAL Routing Algorithm

    PubMed Central

    Estévez, Francisco José; Castillo-Secilla, José María; González, Jesús; Olivares, Joaquín; Glösekötter, Peter

    2017-01-01

    Smart Cities are called to change the daily life of human beings. This concept permits improving the efficiency of our cities in several areas such as the use of water, energy consumption, waste treatment, and mobility both for people as well as vehicles throughout the city. This represents an interconnected scenario in which thousands of embedded devices need to work in a collaborative way both for sensing and modifying the environment properly. Under this scenario, the majority of devices will use wireless protocols for communicating among them, representing a challenge for optimizing the use of the electromagnetic spectrum. When the density of deployed nodes increases, the competition for using the physical medium becomes harder and, in consequence, traffic collisions will be higher, affecting data-rates in the communication process. This work presents mDARAL, a multi-radio routing algorithm based on the Dynamic and Adaptive Radio Algorithm (DARAL), which has the capability of isolating groups of nodes into sub-networks. The nodes of each sub-network will communicate among them using a dedicated radio frequency, thus isolating the use of the radio channel to a reduced number of nodes. Each sub-network will have a master node with two physical radios, one for communicating with its neighbours and the other for being the contact point among its group and other sub-networks. The communication among sub-networks is done through master nodes in a dedicated radio frequency. The algorithm works to maximize the overall performance of the network through the distribution of the traffic messages into unoccupied frequencies. The obtained results show that mDARAL achieves great improvement in terms of the number of control messages necessary to connect a node to the network, convergence time and energy consumption during the connection phase compared to DARAL. PMID:28208760

  8. Delay/Disruption Tolerant Networks for Human Space Flight Video Project

    NASA Technical Reports Server (NTRS)

    Fink, Patrick W.; Ngo, Phong; Schlesinger, Adam

    2010-01-01

    The movie describes collaboration between NASA and Vint Cerf on the development of Disruption Tolerant Networks (DTN) for use in space exploration. Current evaluation efforts at Johnson Space Center are focused on the use of DTNs in space communications. Tests include the ability of rovers to store data for later display, tracking local and remote habitat inventory using radio-frequency identification tags, and merging networks.

  9. The Radio JOVE Project: A Worldwide, Ground-Based, Amateur, Decameter-Wavelength Radio Observatory Network

    NASA Astrophysics Data System (ADS)

    Thieman, J.; Higgins, C.; Flagg, R.; Sky, J.

    2003-05-01

    The Radio JOVE project began over four years ago as an education-centered program to inspire secondary school students' interest in space science through hands-on radio astronomy. Students build a radio receiver and antenna kit capable of receiving Jovian, solar, and galactic emissions at a frequency of 20.1 MHz. More than 500 of these kits have been distributed to students and interested observers (ages 10 through adult) in 24 countries. For those who are not comfortable building their own kit, the Radio JOVE project has made it possible to monitor real-time data and streaming audio online from professional radio telescopes in Florida (http://jupiter.kochi-ct.jp) and Hawaii (http://jupiter.wcc.hawaii.edu/newradiojove/main.html). Freely downloadable software called Radio-Skypipe (http://radiosky.com) emulates a chart recorder to monitor ones own radio telescope or the telescopes of other observers worldwide who send out their data over the Internet. A built-in chat feature allows the users to discuss their observations and results in real time. New software is being developed to allow network users to interactively view a multi-frequency spectroscopic display of the Hawaii radio telescope. The Radio JOVE project is also partnering with NASA's Student Observation Network (http://sunearth.gsfc.nasa.gov/sunearthday/2003/networkintro.htm) in an effort to use online collaborations to monitor and track solar storms as a hands-on science experience for students. We believe the amateur network data to be of value to the research community and would like to have students more directly connected to ongoing research projects to enhance their interest in participating. Results of the project and plans for the future will be highlighted.

  10. GDTN: Genome-Based Delay Tolerant Network Formation in Heterogeneous 5G Using Inter-UA Collaboration.

    PubMed

    You, Ilsun; Sharma, Vishal; Atiquzzaman, Mohammed; Choo, Kim-Kwang Raymond

    2016-01-01

    With a more Internet-savvy and sophisticated user base, there are more demands for interactive applications and services. However, it is a challenge for existing radio access networks (e.g. 3G and 4G) to cope with the increasingly demanding requirements such as higher data rates and wider coverage area. One potential solution is the inter-collaborative deployment of multiple radio devices in a 5G setting designed to meet exacting user demands, and facilitate the high data rate requirements in the underlying networks. These heterogeneous 5G networks can readily resolve the data rate and coverage challenges. Networks established using the hybridization of existing networks have diverse military and civilian applications. However, there are inherent limitations in such networks such as irregular breakdown, node failures, and halts during speed transmissions. In recent years, there have been attempts to integrate heterogeneous 5G networks with existing ad hoc networks to provide a robust solution for delay-tolerant transmissions in the form of packet switched networks. However, continuous connectivity is still required in these networks, in order to efficiently regulate the flow to allow the formation of a robust network. Therefore, in this paper, we present a novel network formation consisting of nodes from different network maneuvered by Unmanned Aircraft (UA). The proposed model utilizes the features of a biological aspect of genomes and forms a delay tolerant network with existing network models. This allows us to provide continuous and robust connectivity. We then demonstrate that the proposed network model has an efficient data delivery, lower overheads and lesser delays with high convergence rate in comparison to existing approaches, based on evaluations in both real-time testbed and simulation environment.

  11. GDTN: Genome-Based Delay Tolerant Network Formation in Heterogeneous 5G Using Inter-UA Collaboration

    PubMed Central

    2016-01-01

    With a more Internet-savvy and sophisticated user base, there are more demands for interactive applications and services. However, it is a challenge for existing radio access networks (e.g. 3G and 4G) to cope with the increasingly demanding requirements such as higher data rates and wider coverage area. One potential solution is the inter-collaborative deployment of multiple radio devices in a 5G setting designed to meet exacting user demands, and facilitate the high data rate requirements in the underlying networks. These heterogeneous 5G networks can readily resolve the data rate and coverage challenges. Networks established using the hybridization of existing networks have diverse military and civilian applications. However, there are inherent limitations in such networks such as irregular breakdown, node failures, and halts during speed transmissions. In recent years, there have been attempts to integrate heterogeneous 5G networks with existing ad hoc networks to provide a robust solution for delay-tolerant transmissions in the form of packet switched networks. However, continuous connectivity is still required in these networks, in order to efficiently regulate the flow to allow the formation of a robust network. Therefore, in this paper, we present a novel network formation consisting of nodes from different network maneuvered by Unmanned Aircraft (UA). The proposed model utilizes the features of a biological aspect of genomes and forms a delay tolerant network with existing network models. This allows us to provide continuous and robust connectivity. We then demonstrate that the proposed network model has an efficient data delivery, lower overheads and lesser delays with high convergence rate in comparison to existing approaches, based on evaluations in both real-time testbed and simulation environment. PMID:27973618

  12. Engineering processes for the African VLBI network

    NASA Astrophysics Data System (ADS)

    Thondikulam, Venkatasubramani L.; Loots, Anita; Gaylard, Michael

    2013-04-01

    The African VLBI Network (AVN) is an initiative by the SKA-SA and HartRAO, business units of the National Research Foundation (NRF), Department of Science and Technology (DST), South Africa. The aim is to fill the existing gap of Very Long Baseline Interferometry (VLBI)-capable radio telescopes in the African continent by a combination of new build as well as conversion of large redundant telecommunication antennas through an Inter-Governmental collaborative programme in Science and Technology. The issue of human capital development in the Continent in the techniques of radio astronomy engineering and science is a strong force to drive the project and is expected to contribute significantly to the success of Square Kilometer Array (SKA) in the Continent.

  13. Collaboration in a Wireless Grid Innovation Testbed by Virtual Consortium

    NASA Astrophysics Data System (ADS)

    Treglia, Joseph; Ramnarine-Rieks, Angela; McKnight, Lee

    This paper describes the formation of the Wireless Grid Innovation Testbed (WGiT) coordinated by a virtual consortium involving academic and non-academic entities. Syracuse University and Virginia Tech are primary university partners with several other academic, government, and corporate partners. Objectives include: 1) coordinating knowledge sharing, 2) defining key parameters for wireless grids network applications, 3) dynamically connecting wired and wireless devices, content and users, 4) linking to VT-CORNET, Virginia Tech Cognitive Radio Network Testbed, 5) forming ad hoc networks or grids of mobile and fixed devices without a dedicated server, 6) deepening understanding of wireless grid application, device, network, user and market behavior through academic, trade and popular publications including online media, 7) identifying policy that may enable evaluated innovations to enter US and international markets and 8) implementation and evaluation of the international virtual collaborative process.

  14. Design, Development and Pre-Flight Testing of the Communications, Navigation, and Networking Reconfigurable Testbed (Connect) to Investigate Software Defined Radio Architecture on the International Space Station

    NASA Technical Reports Server (NTRS)

    Over, Ann P.; Barrett, Michael J.; Reinhart, Richard C.; Free, James M.; Cikanek, Harry A., III

    2011-01-01

    The Communication Navigation and Networking Reconfigurable Testbed (CoNNeCT) is a NASA-sponsored mission, which will investigate the usage of Software Defined Radios (SDRs) as a multi-function communication system for space missions. A softwaredefined radio system is a communication system in which typical components of the system (e.g., modulators) are incorporated into software. The software-defined capability allows flexibility and experimentation in different modulation, coding and other parameters to understand their effects on performance. This flexibility builds inherent redundancy and flexibility into the system for improved operational efficiency, real-time changes to space missions and enhanced reliability/redundancy. The CoNNeCT Project is a collaboration between industrial radio providers and NASA. The industrial radio providers are providing the SDRs and NASA is designing, building and testing the entire flight system. The flight system will be integrated on the Express Logistics Carrier (ELC) on the International Space Station (ISS) after launch on the H-IIB Transfer Vehicle in 2012. This paper provides an overview of the technology research objectives, payload description, design challenges and pre-flight testing results.

  15. Using Trust to Establish a Secure Routing Model in Cognitive Radio Network.

    PubMed

    Zhang, Guanghua; Chen, Zhenguo; Tian, Liqin; Zhang, Dongwen

    2015-01-01

    Specific to the selective forwarding attack on routing in cognitive radio network, this paper proposes a trust-based secure routing model. Through monitoring nodes' forwarding behaviors, trusts of nodes are constructed to identify malicious nodes. In consideration of that routing selection-based model must be closely collaborative with spectrum allocation, a route request piggybacking available spectrum opportunities is sent to non-malicious nodes. In the routing decision phase, nodes' trusts are used to construct available path trusts and delay measurement is combined for making routing decisions. At the same time, according to the trust classification, different responses are made specific to their service requests. By adopting stricter punishment on malicious behaviors from non-trusted nodes, the cooperation of nodes in routing can be stimulated. Simulation results and analysis indicate that this model has good performance in network throughput and end-to-end delay under the selective forwarding attack.

  16. Effects of the 2017 Solar Eclipse on HF Radio Propagation and the D-Region Ionosphere: Citizen Science Investigation

    NASA Astrophysics Data System (ADS)

    Fry, C. D.; Adams, M.; Gallagher, D. L.; Habash Krause, L.; Rawlins, L.; Suggs, R. M.; Anderson, S. C.

    2017-12-01

    August 21, 2017 provided a unique opportunity to investigate the effects of the total solar eclipse on high frequency (HF) radio propagation and ionospheric variability. In Marshall Space Flight Center's partnership with the US Space and Rocket Center (USSRC) and Austin Peay State University (APSU), we engaged students and citizen scientists in an investigation of the eclipse effects on the mid-latitude ionosphere. The Amateur Radio community has developed several automated receiving and reporting networks that draw from widely-distributed, automated and manual radio stations to build a near-real time, global picture of changing radio propagation conditions. We used these networks and employed HF radio propagation modeling in our investigation. A Ham Radio Science Citizen Investigation (HamSCI) collaboration with the American Radio Relay League (ARRL) ensured that many thousands of amateur radio operators would be "on the air" communicating on eclipse day, promising an extremely large quantity of data would be collected. Activities included implementing and configuring software, monitoring the HF Amateur Radio frequency bands and collecting radio transmission data on days before, the day of, and days after the eclipse to build a continuous record of changing propagation conditions as the moon's shadow marched across the United States. Our expectations were the D-Region ionosphere would be most impacted by the eclipse, enabling over-the-horizon radio propagation on lower HF frequencies (3.5 and 7 MHz) that are typically closed during the middle of the day. Post-eclipse radio propagation analysis provided insights into ionospheric variability due to the eclipse. We report on results, interpretation, and conclusions of these investigations.

  17. Collaboration and Development of Radio Astronomy in Australasia and South-Pacific Region: New Zealand Perspectives

    NASA Astrophysics Data System (ADS)

    Gulyaev, S.; Natusch, T.

    2006-08-01

    Radio telescopes in the Asia-Pacific region form a natural network for VLBI observations, similar to the very successful networks in North America (Network Users Group) and Europe (European VLBI Network). New Zealand's VLBI facility, which we are developing since 2005, has the potential to strengthen the Asian-Pacific VLBI network and its role in astronomy, geodesy and geoscience. It will positively influence regional and international activities in geoscience and geodesy that advance New Zealand's national interests. A self-contained radio astronomy system for VLBI, including a 1.658 GHz (centre frequency), 16 MHz bandwidth RF system (feed and downconversion system locked to a Rubidium maser and GPS clock), an 8-bit sampler/digitisation system, and a disk-based recording system built around a commodity PC was developed in New Zealand Centre for Radiophysics and Space Research. This was designed as a portable system for use on various radio telescopes. A number of Trans-Tasman tests has been conducted in 2005-2006 between the CRSR system installed on a 6 metre dish located in Auckland and the Australia Telescope Compact Array in Narrabri, Australia. This work has been successful, with fringes located from the recorded data and high resolution image of the quasar PKS1921-231 obtained. Experiments were recently conducted with Japan; new tests are planned with Korea and Fiji. Plans have been made to build a new 16.5 m antenna in New Zealand's North Island and to upgrade an 11 m dish in the South Island. A possible future of New Zealand's participation in the SKA is being discussed.

  18. Can You Hear Us Now? Investigating the Effects of a Wireless Grid Social Radio Station on Collaboration and Communication in Fragile Populations

    ERIC Educational Resources Information Center

    Chauncey, Sarah A.

    2012-01-01

    The ability to interact with peers and coworkers in online digital networks is essential in learning and business environments. Our digital participatory culture is based on communication in response to purposeful activity and is facilitated by information and communication technologies (ICT). Students with emotional, behavioral, and learning…

  19. A Student's Hands-on Introduction to Radio Astronomy With the Simple Construction, Operation and Testing, Utilizing Commonly Available Materials, of a Functioning Solar Radio Telescope

    NASA Astrophysics Data System (ADS)

    Knight, D.

    2016-12-01

    Our study of the Sun, an object that provides life to this planet but also is a serious threat to the existence we now enjoy, is frequently limited in hands-on activities by the unavailability of the necessary observational tools. While small optical telescopes are more easily obtained, telescopes that work the other regions of the electromagnetic spectrum, such as the radio frequencies, are unusual. Radio emissions from solar storms, however, can be "viewed" by a student constructing a simple, tunable and inexpensive radio telescope designed to receive the most common radio frequencies broadcast from the Sun during such a storm. The apparatus employs normally available materials and technology in new purposes. Utilizing this telescope, students have the ability to test and modify its design for changes in frequency and signal amplitude, and therefore examine a wide spectrum of radio emission emanating from our star. This engaging introduction to radio electronics not only involves the study of the electrical circuit involved, but also sets the student up for detailed study in the form of specific research projects focusing on solar activity in the radio wavelengths. So far, my students have been actively involved in varying the electrical properties of a simple one-transistor circuit that selects the observational frequencies of the solar radio telescope they have constructed. Student research projects also have examined antenna design in terms of directionality and signal strength gain. In the future, collaboration is possible to link student observers in different locations on this planet, allowing for significant peer evaluation and cooperation. NASA's "Project Jove", a program that Sonoma Valley High School and Robert Ferguson Observatory have been connected with since about the year 2000, already has a worldwide collaboration network in place for similar student-operated radio telescopes for primarily studying Jupiter. Because of the higher frequencies with most of the solar storm radio spectrum, our apparatus is correspondingly much smaller and easier to manipulate, thus promoting student research on a much larger scale.

  20. Collaborative localization in wireless sensor networks via pattern recognition in radio irregularity using omnidirectional antennas.

    PubMed

    Jiang, Joe-Air; Chuang, Cheng-Long; Lin, Tzu-Shiang; Chen, Chia-Pang; Hung, Chih-Hung; Wang, Jiing-Yi; Liu, Chang-Wang; Lai, Tzu-Yun

    2010-01-01

    In recent years, various received signal strength (RSS)-based localization estimation approaches for wireless sensor networks (WSNs) have been proposed. RSS-based localization is regarded as a low-cost solution for many location-aware applications in WSNs. In previous studies, the radiation patterns of all sensor nodes are assumed to be spherical, which is an oversimplification of the radio propagation model in practical applications. In this study, we present an RSS-based cooperative localization method that estimates unknown coordinates of sensor nodes in a network. Arrangement of two external low-cost omnidirectional dipole antennas is developed by using the distance-power gradient model. A modified robust regression is also proposed to determine the relative azimuth and distance between a sensor node and a fixed reference node. In addition, a cooperative localization scheme that incorporates estimations from multiple fixed reference nodes is presented to improve the accuracy of the localization. The proposed method is tested via computer-based analysis and field test. Experimental results demonstrate that the proposed low-cost method is a useful solution for localizing sensor nodes in unknown or changing environments.

  1. An IT-enabled supply chain model: a simulation study

    NASA Astrophysics Data System (ADS)

    Cannella, Salvatore; Framinan, Jose M.; Barbosa-Póvoa, Ana

    2014-11-01

    During the last decades, supply chain collaboration practices and the underlying enabling technologies have evolved from the classical electronic data interchange (EDI) approach to a web-based and radio frequency identification (RFID)-enabled collaboration. In this field, most of the literature has focused on the study of optimal parameters for reducing the total cost of suppliers, by adopting operational research (OR) techniques. Herein we are interested in showing that the considered information technology (IT)-enabled structure is resilient, that is, it works well across a reasonably broad range of parameter settings. By adopting a methodological approach based on system dynamics, we study a multi-tier collaborative supply chain. Results show that the IT-enabled supply chain improves operational performance and customer service level. Nonetheless, benefits for geographically dispersed networks are of minor entity.

  2. Cognitive radio wireless sensor networks: applications, challenges and research trends.

    PubMed

    Joshi, Gyanendra Prasad; Nam, Seung Yeob; Kim, Sung Won

    2013-08-22

    A cognitive radio wireless sensor network is one of the candidate areas where cognitive techniques can be used for opportunistic spectrum access. Research in this area is still in its infancy, but it is progressing rapidly. The aim of this study is to classify the existing literature of this fast emerging application area of cognitive radio wireless sensor networks, highlight the key research that has already been undertaken, and indicate open problems. This paper describes the advantages of cognitive radio wireless sensor networks, the difference between ad hoc cognitive radio networks, wireless sensor networks, and cognitive radio wireless sensor networks, potential application areas of cognitive radio wireless sensor networks, challenges and research trend in cognitive radio wireless sensor networks. The sensing schemes suited for cognitive radio wireless sensor networks scenarios are discussed with an emphasis on cooperation and spectrum access methods that ensure the availability of the required QoS. Finally, this paper lists several open research challenges aimed at drawing the attention of the readers toward the important issues that need to be addressed before the vision of completely autonomous cognitive radio wireless sensor networks can be realized.

  3. Collaborative Wideband Compressed Signal Detection in Interplanetary Internet

    NASA Astrophysics Data System (ADS)

    Wang, Yulin; Zhang, Gengxin; Bian, Dongming; Gou, Liang; Zhang, Wei

    2014-07-01

    As the development of autonomous radio in deep space network, it is possible to actualize communication between explorers, aircrafts, rovers and satellites, e.g. from different countries, adopting different signal modes. The first mission to enforce the autonomous radio is to detect signals of the explorer autonomously without disturbing the original communication. This paper develops a collaborative wideband compressed signal detection approach for InterPlaNetary (IPN) Internet where there exist sparse active signals in the deep space environment. Compressed sensing (CS) can be utilized by exploiting the sparsity of IPN Internet communication signal, whose useful frequency support occupies only a small portion of an entirely wide spectrum. An estimate of the signal spectrum can be obtained by using reconstruction algorithms. Against deep space shadowing and channel fading, multiple satellites collaboratively sense and make a final decision according to certain fusion rule to gain spatial diversity. A couple of novel discrete cosine transform (DCT) and walsh-hadamard transform (WHT) based compressed spectrum detection methods are proposed which significantly improve the performance of spectrum recovery and signal detection. Finally, extensive simulation results are presented to show the effectiveness of our proposed collaborative scheme for signal detection in IPN Internet. Compared with the conventional discrete fourier transform (DFT) based method, our DCT and WHT based methods reduce computational complexity, decrease processing time, save energy and enhance probability of detection.

  4. Cognitive Radio Wireless Sensor Networks: Applications, Challenges and Research Trends

    PubMed Central

    Joshi, Gyanendra Prasad; Nam, Seung Yeob; Kim, Sung Won

    2013-01-01

    A cognitive radio wireless sensor network is one of the candidate areas where cognitive techniques can be used for opportunistic spectrum access. Research in this area is still in its infancy, but it is progressing rapidly. The aim of this study is to classify the existing literature of this fast emerging application area of cognitive radio wireless sensor networks, highlight the key research that has already been undertaken, and indicate open problems. This paper describes the advantages of cognitive radio wireless sensor networks, the difference between ad hoc cognitive radio networks, wireless sensor networks, and cognitive radio wireless sensor networks, potential application areas of cognitive radio wireless sensor networks, challenges and research trend in cognitive radio wireless sensor networks. The sensing schemes suited for cognitive radio wireless sensor networks scenarios are discussed with an emphasis on cooperation and spectrum access methods that ensure the availability of the required QoS. Finally, this paper lists several open research challenges aimed at drawing the attention of the readers toward the important issues that need to be addressed before the vision of completely autonomous cognitive radio wireless sensor networks can be realized. PMID:23974152

  5. Underwater Electromagnetic Sensor Networks, Part II: Localization and Network Simulations

    PubMed Central

    Zazo, Javier; Valcarcel Macua, Sergio; Zazo, Santiago; Pérez, Marina; Pérez-Álvarez, Iván; Jiménez, Eugenio; Cardona, Laura; Brito, Joaquín Hernández; Quevedo, Eduardo

    2016-01-01

    In the first part of the paper, we modeled and characterized the underwater radio channel in shallow waters. In the second part, we analyze the application requirements for an underwater wireless sensor network (U-WSN) operating in the same environment and perform detailed simulations. We consider two localization applications, namely self-localization and navigation aid, and propose algorithms that work well under the specific constraints associated with U-WSN, namely low connectivity, low data rates and high packet loss probability. We propose an algorithm where the sensor nodes collaboratively estimate their unknown positions in the network using a low number of anchor nodes and distance measurements from the underwater channel. Once the network has been self-located, we consider a node estimating its position for underwater navigation communicating with neighboring nodes. We also propose a communication system and simulate the whole electromagnetic U-WSN in the Castalia simulator to evaluate the network performance, including propagation impairments (e.g., noise, interference), radio parameters (e.g., modulation scheme, bandwidth, transmit power), hardware limitations (e.g., clock drift, transmission buffer) and complete MAC and routing protocols. We also explain the changes that have to be done to Castalia in order to perform the simulations. In addition, we propose a parametric model of the communication channel that matches well with the results from the first part of this paper. Finally, we provide simulation results for some illustrative scenarios. PMID:27999309

  6. Capabilities and prospects of the East Asia Very Long Baseline Interferometry Network

    NASA Astrophysics Data System (ADS)

    An, T.; Sohn, B. W.; Imai, H.

    2018-02-01

    The very long baseline interferometry (VLBI) technique offers angular resolutions superior to any other instruments at other wavelengths, enabling unique science applications of high-resolution imaging of radio sources and high-precision astrometry. The East Asia VLBI Network (EAVN) is a collaborative effort in the East Asian region. The EAVN currently consists of 21 telescopes with diverse equipment configurations and frequency setups, allowing flexible subarrays for specific science projects. The EAVN provides the highest resolution of 0.5 mas at 22 GHz, allowing the fine imaging of jets in active galactic nuclei, high-accuracy astrometry of masers and pulsars, and precise spacecraft positioning. The soon-to-be-operational Five-hundred-meter Aperture Spherical radio Telescope (FAST) will open a new era for the EAVN. This state-of-the-art VLBI array also provides easy access to and crucial training for the burgeoning Asian astronomical community. This Perspective summarizes the status, capabilities and prospects of the EAVN.

  7. 12th European VLBI Network Symposium and Users Meeting

    NASA Astrophysics Data System (ADS)

    Tarchi, Andrea; Giroletti, Marcello; Feretti, Luigina

    The Istituto di Radioastronomia (IRA) di Bologna and the Osservatorio Astronomico di Cagliari (OAC), on behalf of the European VLBI Consortium, hosted the 12th European VLBI Network (EVN) Symposium and Users Meeting. The Conference was held from 7th to 10th of October at the Hotel Regina Margherita, in the center of Cagliari. The latest scientific results and technical developments from VLBI, and, in particular, e-VLBI and space-VLBI (RadioAstron) outcomes were reported. The timing of this meeting coincided with the first successful observational tests of the Sardinia Radio Telescopes within the EVN, and with a number of results from new and upgraded radio facilities around the globe, such as e-MERLIN, ALMA, and the SKA pathfinders. The symposium was attended by 133 participants from all over the world, with the Asian community represented by more than 20 colleagues. The program of the meeting consisted of 70 oral contributions (including 8 invited speakers) and 50 poster that covered a very wide range of VLBI topics both in galactic and extragalactic astrophysics (e.g., AGN, stellar evolution from birth to death, astrometry, and planetary science) as well as technological developments and future international collaborations. The scientific program also included a visit to the 64-m Sardinia Radio Telescope (SRT) and the EVN Users Meeting, where astronomers have provided useful feedback on various matters regarding EVN operations. The research leading to these results has received funding from the European Commission Seventh Framework Programme (FP/2007-2013) under grant agreement No 283393 (RadioNet3). EDITORIAL BOARD: Andrea Tarchi, Marcello Giroletti, Luigina Feretti

  8. A general method for radio spectrum efficiency defining

    NASA Astrophysics Data System (ADS)

    Ramadanovic, Ljubomir M.

    1986-08-01

    A general method for radio spectrum efficiency defining is proposed. Although simple it can be applied to various radio services. The concept of spectral elements, as information carriers, is introduced to enable the organization of larger spectral spaces - radio network models - characteristic for a particular radio network. The method is applied to some radio network models, concerning cellular radio telephone systems and digital radio relay systems, to verify its unified approach capability. All discussed radio services operate continuously.

  9. Amateur Radio Communications with a Deep Space Probe (Yes, It's Possible)

    NASA Astrophysics Data System (ADS)

    Cudnik, Brian; Rahman, Mahmudur; Saganti, Seth; Erickson, Gary M.; Saganti, Premkumar

    2015-05-01

    Prairie View A&M University through the collaboration with NASA-Johnson Space Center has partnered with the Kyushu Institute of Technology (KIT), Japan and developed a payload for the Shinen-2 spacecraft that was launched from Japan on December 3, 2014 as part of the Hayabusa2 mission. The main purpose of the Shinen-2 spacecraft is deep space communication experiment to test the feasibility of deep-space radio communications from the spacecraft to Earth without the need of the Deep Space Network (DSN) of NASA. This presents an opportunity to the wider community of amateur astronomers, ham radio operators, and other research personnel in that they will have the opportunity to work with deep space communication such as Shinen-2 spacecraft. It should be possible to detect a signal as an increased strength from Shinen-2 spacecraft at a rest frequency of 437.385 MHz, using commercially available equipment procured at low-cost, when the spacecraft approaches to within 3,000,000 km of the Earth during December 2015.

  10. Navigation of the space VLBI mission-HALCA

    NASA Technical Reports Server (NTRS)

    You, Tung Han; Ellis, Jordan; Mottinger, Neil

    1998-01-01

    In February 1997, the Japanese Space Agency ISAS launched the first space VLBI satellite, HALCA, with an 8 meter diameter wire mesh antenna and radio astronomy receivers capable of observing at 1.6, 4.8, and 22 Ghz. In a 560 by 21000 km orbit with a 6 hour period and 31 degree inclination, it observes celestial radio sources in conjunction with a world wide network of ground radio telescopes as part of an international collaborative effort which includes facilities in Japan, the U.S., Canada, Australia, and Europe. JPL is providing tracking and navigation support using a dedicated subnet of 11 meter antennas as well as co-observations using the DSN 70 meter antennas. This paper describes the spacecraft dynamics model and orbit determination strategies developed to meet the stringent trajectory accuracy requirements for generating predictions for the transfer of a stable uplink frequency to the spacecraft and for determining reconstructed orbits for delivery to the NRAO VLBI correlator and the international VLBI science community.

  11. Hands-on Universe - Europe

    NASA Astrophysics Data System (ADS)

    Ferlet, R.

    2006-08-01

    The EU-HOU project aims at re-awakening the interest for science through astronomy and new technologies, by challenging middle and high schools pupils. It relies on real observations acquired through an internet-based network of robotic optical and radio telescopes or with didactical tools such as Webcam. Pupils manipulate and measure images in the classroom environment, using the specifically designed software SalsaJ, within pedagogical trans-disciplinary resources constructed in close collaboration between researchers and teachers. Gathering eight European countries coordinated in France, EU-HOU is partly funded by the European Union. All its outputs are freely available on the Web, in English and the other languages involved. A European network of teachers is being developed through training sessions.

  12. Hands-on Universe - Europe

    NASA Astrophysics Data System (ADS)

    Ferlet, R.

    The EU-HOU project aims at re-awakening the interest for science through astronomy and new technologies, by challenging middle and high schools pupils. It relies on real observations acquired through an internet-based network of robotic optical and radio telescopes or with didactical tools such as Webcam. Pupils manipulate and measure images in the classroom environment, using the specifically designed software SalsaJ, within pedagogical trans-disciplinary resources constructed in close collaboration between researchers and teachers. Gathering eight European countries coordinated in France, EU-HOU is partly funded by the European Union. All its outputs are freely available on the Web, in English and the other languages involved. A European network of teachers is being developed through training sessions.

  13. New results on the exotic galaxy `Speca' and discovering many more Specas with RAD@home network

    NASA Astrophysics Data System (ADS)

    Hota, Ananda; Croston, Judith H.; Ohyama, Youichi; Stalin, C. S.; Hardcastle, Martin J.; Konar, Chiranjib; Aravind, R. P.; Agarwal, Sheena M.; Dharmik Bhoga, Sai Arun; Dabhade, Pratik; Kamble, Amit A.; Mohanty, Pradeepta K.; Mukherjee, Alok; Pandey, Akansha V.; Patra, Alakananda; Pechetti, Renuka; Raut, Shrishail S.; Sushma, V.; Vaddi, Sravani; Verma, Nishchhal

    We present the first report on an innovative new project named "RAD@home", a citizen-science research collaboratory built on free web-services like Facebook, Google, Skype, NASA Skyview, NED, TGSS etc.. This is the first of its kind in India, a zero-funded, zero-infrastructure, human-resource network to educate and directly involve in research, hundreds of science-educated under-graduate population of India, irrespective of their official employment and home-location with in the country. Professional international collaborators are involved in follow up observation and publication of the objects discovered by the collaboratory. We present here ten newly found candidate episodic radio galaxies, already proposed to GMRT, and ten more interesting cases which includes, bent-lobe radio galaxies located in new Mpc-scale filaments, likely tracing cosmological cluster accretion from the cosmic web. Two new Speca-like rare spiral-host large radio galaxies have also been been reported here. Early analyses from our follow up observations with the Subaru and XMM-Newton telescopes have revealed that Speca is likely a new entry to the cluster and is a fast rotating, extremely massive, star forming disk galaxy. Speca-like massive galaxies with giant radio lobes, are possibly remnants of luminous quasars in the early Universe or of first supermassive black holes with in first masssve galaxies. As discoveries of Speca-like galaxies did not require new data from big telescopes, but free archival radio-optical data, these early results demonstrate the discovery potential of RAD@home and how it can help resource-rich professionals, as well as demonstrate a model of academic-growth for resource-poor people in the underdeveloped regions via Internet.

  14. AN/VRC 118 Mid-Tier Networking Vehicular Radio (MNVR) and Joint Enterprise Network Manager (JENM) Early Fielding Report

    DTIC Science & Technology

    2017-01-18

    1 AN/VRC 118 Mid-Tier Networking Vehicular Radio and Joint Enterprise Network Manager Early Fielding Report This report provides my assessment of...the AN/VRC-118 Mid-Tier Networking Vehicular Radio (MNVR) and the Joint Enterprise Network Manager (JENM) in support of the Army’s fielding of low...September 2016 ADM does not address the JENM, which must be fielded with MNVR to allow soldiers to configure and manage the software- defined radio

  15. A Practical Terrestrial Packet Radio Network.

    DTIC Science & Technology

    1983-11-01

    12 Howard Frank, Israel Gitman and Richard Van Slyke , "Packet Radio System--Network Considerations," AFIPS Conference Proceedings, Anaheim, 1975...p, 1396. 33 Howard Frank, Israel Gitman and Richard Van Slyke, "Packet Radio System--Network Considerations," AFIPS...44, 1975 NCC, Anaheim, pp. 233-242. J 149 I : Frank, Howard, Israel Gitman and Richard Van Slyke, "Packet Radio System — Network

  16. GLOBECOM '89 - IEEE Global Telecommunications Conference and Exhibition, Dallas, TX, Nov. 27-30, 1989, Conference Record. Volumes 1, 2, & 3

    NASA Astrophysics Data System (ADS)

    The present conference discusses topics in multiwavelength network technology and its applications, advanced digital radio systems in their propagation environment, mobile radio communications, switching programmability, advancements in computer communications, integrated-network management and security, HDTV and image processing in communications, basic exchange communications radio advancements in digital switching, intelligent network evolution, speech coding for telecommunications, and multiple access communications. Also discussed are network designs for quality assurance, recent progress in coherent optical systems, digital radio applications, advanced communications technologies for mobile users, communication software for switching systems, AI and expert systems in network management, intelligent multiplexing nodes, video and image coding, network protocols and performance, system methods in quality and reliability, the design and simulation of lightwave systems, local radio networks, mobile satellite communications systems, fiber networks restoration, packet video networks, human interfaces for future networks, and lightwave networking.

  17. The Ilgarijiri Project: A collaboration between Aboriginal communities and radio astronomers in the Murchison Region of Western Australia

    NASA Astrophysics Data System (ADS)

    Goldsmith, John

    2014-07-01

    The international radio astronomy initiative known as the Square Kilometre Array is a cutting-edge science project, aimed atdramatically expanding our vision and understanding of the Universe. The $2billion+ international project is being shared between Southern Africa and Australia. The Australian component, centred in the Murchison region of Western Australia, is based upon collaboration with Aboriginal communities. A collaborative project called "Ilgarijiri- Things Belonging to the Sky" shared scientific and Aboriginal knowledge of the night sky. Through a series of collaborative meetings and knowledge sharing, the Ilgarijiri project developed and showcased Aboriginal knowledge of the night sky, via an international touring Aboriginal art exhibition, in Australia, South Africa, the USA and Europe. The Aboriginal art exhibition presents Aboriginal stories relating to the night sky, which prominently feature the 'Seven Sisters' and the 'Emu', as well as the collaborative experience with radio astronomers. The success of the Ilgarijiri collaborative project is based upon several principles, which can help to inform and guide future cultural collaborative projects.

  18. The RadioSat (sm) network

    NASA Technical Reports Server (NTRS)

    Noreen, Gary K.

    1991-01-01

    The RadioSat network under development by radio Satellite Corporation will use mobile satellite (MSAT) technology to provide diverse personal communications, broadcast, and navigation services. The network will support these services simultaneously for integrated mobile radios throughout Canada and the United States. The RadioSat network takes advantage of several technological breakthroughs, all coming to fruition by the time the first MSAT satellite is launched in 1994. The most important of these breakthroughs is the enormous radiated power of each MSAT spacecraft - orders of magnitude greater than the radiated power of previous L-band spacecraft. Another important breakthrough is the development of advanced digital audio compression algorithms, enabling the transmission of broadcast quality music at moderate data rates. Finally, continuing dramatic increases in VLSI capabilities permit the production of complex, multi-function mobile satellite radios in very large quantities at prices little more than those of conventional car radios. In addition to performance breakthroughs and their economic implications to RadioSat, the design of the RadioSat network is reviewed.

  19. The Deep Space Network: An instrument for radio astronomy research

    NASA Technical Reports Server (NTRS)

    Renzetti, N. A.; Levy, G. S.; Kuiper, T. B. H.; Walken, P. R.; Chandlee, R. C.

    1988-01-01

    The NASA Deep Space Network operates and maintains the Earth-based two-way communications link for unmanned spacecraft exploring the solar system. It is NASA's policy to also make the Network's facilities available for radio astronomy observations. The Network's microwave communication systems and facilities are being continually upgraded. This revised document, first published in 1982, describes the Network's current radio astronomy capabilities and future capabilities that will be made available by the ongoing Network upgrade. The Bibliography, which includes published papers and articles resulting from radio astronomy observations conducted with Network facilities, has been updated to include papers to May 1987.

  20. RadioSource.NET: Case-Study of a Collaborative Land-Grant Internet Audio Project.

    ERIC Educational Resources Information Center

    Sohar, Kathleen; Wood, Ashley M.; Ramirez, Roberto

    2002-01-01

    Provides a case study of RadioSource.NET, an Internet broadcasting venture developed collaboratively by land-grant university communication departments to share resources, increase online distribution, and promote access to agricultural and natural and life science research. Describes planning, marketing, and implementation processes. (Contains 18…

  1. International Agreement Will Advance Radio Astronomy

    NASA Astrophysics Data System (ADS)

    2007-12-01

    Two of the world's leading astronomical institutions have formalized an agreement to cooperate on joint efforts for the technical and scientific advancement of radio astronomy. The National Radio Astronomy Observatory (NRAO) in the United States and the Max-Planck Institute for Radioastronomy (MPIfR) in Germany concluded a Memorandum of Understanding outlining planned collaborative efforts to enhance the capabilities of each other's telescopes and to expand their cooperation in scientific research. The VLBA The VLBA CREDIT: NRAO/AUI/NSF In the first project pursued under this agreement, the MPIfR will contribute $299,000 to upgrade the continent-wide Very Long Baseline Array's (VLBA) capability to receive radio emissions at a frequency of 22 GHz. This improvement will enhance the VLBA's scientific productivity and will be particularly important for cutting-edge research in cosmology and enigmatic cosmic objects such as gamma-ray blazars. "This agreement follows many years of cooperation between our institutions and recognizes the importance of international collaboration for the future of astronomical research," said Fred K.Y. Lo, NRAO Director. "Our two institutions have many common research goals, and joining forces to keep all our telescopes at the forefront of technology will be highly beneficial for the science," said Anton Zensus, Director at MPIfR. In addition to the VLBA, the NRAO operates the Very Large Array (VLA) in New Mexico and the Robert C. Byrd Green Bank Telescope (GBT) in West Virginia. The MPIfR operates the 100-meter Effelsberg Radio Telescope in Germany and the 12-meter APEX submillimeter telescope in 5100 m altitude in the Cilean Atacama desert (together with the European Southern Observatory and the Swedish Onsala Space Observatory). With the 100-meter telescope, it is part of the VLBA network in providing transatlantic baselines. Both institutions are members of a global network of telescopes (the Global VLBI Network) that uses simultaneous observations to produce extremely high-resolution images, and another network (the High Sensitivity Array) that uses the same technique with large telescopes to observe particularly faint celestial objects. With this technique, NRAO telescopes work with MPIfR's Effelsberg telescope to produce images hundreds of times more detailed than those from the Hubble Space Telescope. Both institutions also are part of the international collaboration building the Atacama Large Millimeter/submillimeter Array (ALMA) in Chile and of the international planning effort to build a Square Kilometer Array. The VLBA is a system of ten antennas, each with a dish 25 meters in diameter. From Mauna Kea on the Big Island of Hawaii to St. Croix in the U.S. Virgin Islands, the VLBA spans more than 8000 kilometers. Under the new agreement, the two institutions will continue their previous observational collaborations, and in addition will share resources to improve the technical capabilities of each other's telescopes, particularly at short wavelengths, They also will collaborate in the peer-reviewed process each uses to allocate observing time, and agree to mutually maintain an "open skies" policy allowing open access to each other's telescopes on a peer-reviewed basis. The agreement notes the report of the U.S. National Science Foundation's (NSF) Senior Review committee, which called upon the NRAO to seek partners to contribute to the operation of the VLBA. The MPIfR affirms its strong interest in maintaining the VLBA's unique scientific capabilities, and its monetary contribution toward the 22 GHz upgrade of the VLBA is a solid sign of that commitment. "The VLBA provides the greatest resolving power of any instrument in astronomy, and the MPIfR's contribution to enhancing its capabilities is an important validation of the VLBA's importance to frontier astrophysics," Lo said. The joint VLBA project calls for the MPIfR to fund the receiving-system upgrades and the NRAO to perform the work. The project is scheduled to be complete, with all 10 VLBA antennas upgraded, in August of 2008. The upgrade will make the VLBA's receiving system for 22 GHz 30 percent more sensitive. This will enhance the VLBA's capability to advance a key area of science using rotating disks of water molecules at the cores of distant galaxies to make precise measurements of the distances to those galaxies. This technique, first used in the late 1990s, can measure large cosmic distances directly, without relying on various assumptions required for more indirect techniques. The improved precision is important to resolving a number of frontier astrophysical problems, including the nature of the mysterious "dark energy" that appears to be accelerating the expansion of the Universe. This research project involves scientists from both MPIfR and NRAO, and, in addition to the VLBA, the Effelsberg telescope, the GBT and the VLA. The National Radio Astronomy Observatory is a facility of the National Science Foundation, operated under cooperative agreement by Associated Universities, Inc. The Max Planck Institute for Radio Astronomy is one of about 80 research institutes of the Max Planck Society for the Promotion of Research in Germany.

  2. A terrain based simulation system to predict the interference caused by networks of spread spectrum systems

    NASA Astrophysics Data System (ADS)

    Hagen, William E.; Holtzman, Julian C.

    The Army Terrain Integrated Interference Prediction System (ATIIPS), a CAD terrain based simulation tool for determining the degradation effects on a network on nonspread spectrum radios caused by a network of spread spectrum radios is presented. A brief overview of the program is given, with typical graphics displays shown. Typical results for both a link simulation of interference and for a network simulation, using a slow hopped FM/FSK spread spectrum interfering radio network on a narrow band FM/FSK fixed frequency digital radio are presented.

  3. Performance Evaluation of Multihop Packet Radio Networks by Simulation

    DTIC Science & Technology

    1987-03-01

    Multihop Packet Radio Networks," Proc. IEEE, Vol. 75, No. 1, January 1987. [15] 1. Gitman , "On the Capacity of Slotted ALOHA Networks and Some Design...Networks in the Presence of Noise," Proc. Infocom, Washington D. C., April 1985 [40] H. Frank, I. Gitman and R. Van Slyke, " Packet Radio System

  4. Mesh Network Architecture for Enabling Inter-Spacecraft Communication

    NASA Technical Reports Server (NTRS)

    Becker, Christopher; Merrill, Garrick

    2017-01-01

    To enable communication between spacecraft operating in a formation or small constellation, a mesh network architecture was developed and tested using a time division multiple access (TDMA) communication scheme. The network is designed to allow for the exchange of telemetry and other data between spacecraft to enable collaboration between small spacecraft. The system uses a peer-to-peer topology with no central router, so that it does not have a single point of failure. The mesh network is dynamically configurable to allow for addition and subtraction of new spacecraft into the communication network. Flight testing was performed using an unmanned aerial system (UAS) formation acting as a spacecraft analogue and providing a stressing environment to prove mesh network performance. The mesh network was primarily devised to provide low latency, high frequency communication but is flexible and can also be configured to provide higher bandwidth for applications desiring high data throughput. The network includes a relay functionality that extends the maximum range between spacecraft in the network by relaying data from node to node. The mesh network control is implemented completely in software making it hardware agnostic, thereby allowing it to function with a wide variety of existing radios and computing platforms..

  5. Creating a Collaborative "Hot Clock": Using Smart Phones to Motivate Students' Learning in News Interviewing and Reporting

    ERIC Educational Resources Information Center

    Wei, Fang-Yi Flora

    2016-01-01

    This unit activity is integrated into the chapters on radio of the appropriate course--Survey of Mass Media, Broadcast Journalism, News Writing, Media Programing, or Communication Technology. Employing the concept of a "hot-clock radio format," the purpose of this unit activity is to motivate students' collaborative learning in news…

  6. HISPANIC ENVIRONMENTAL AND WASTE MANAGEMENT OUTREACH PROJECT

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Sebastian Puente

    The Department of Energy Office of Environmental Management (DOE-EM) in cooperation with the Self Reliance Foundation (SRF) is conducting the Hispanic Environmental and Waste Management Outreach Project (HEWMO) to increase science and environmental literacy, specifically that related to nuclear engineering and waste management in the nuclear industry, among the US Hispanic population. The project will encourage Hispanic youth and young adults to pursue careers through the regular presentation of Spanish-speaking scientists and engineers and other role models, as well as career information on nationally broadcast radio programs reaching youth and parents. This project will encourage making science, mathematics, and technologymore » a conscious part of the everyday life experiences of Hispanic youth and families. The SRF in collaboration with the Hispanic Radio Network (HRN) produces and broadcasts radio programs to address the topics and meet the objectives as outlined in the Environmental Literacy Plan and DOE-EM Communications Plan in this document. The SRF has in place a toll-free ''800'' number Information and Resource Referral (I and RR) service that national radio program listeners can call to obtain information and resource referrals as well as give their reactions to the radio programs that will air. HRN uses this feature to put listeners in touch with local organizations and resources that can provide them with further information and assistance on the related program topics.« less

  7. Foundations of data-intensive science: Technology and practice for high throughput, widely distributed, data management and analysis systems

    NASA Astrophysics Data System (ADS)

    Johnston, William; Ernst, M.; Dart, E.; Tierney, B.

    2014-04-01

    Today's large-scale science projects involve world-wide collaborations depend on moving massive amounts of data from an instrument to potentially thousands of computing and storage systems at hundreds of collaborating institutions to accomplish their science. This is true for ATLAS and CMS at the LHC, and it is true for the climate sciences, Belle-II at the KEK collider, genome sciences, the SKA radio telescope, and ITER, the international fusion energy experiment. DOE's Office of Science has been collecting science discipline and instrument requirements for network based data management and analysis for more than a decade. As a result of this certain key issues are seen across essentially all science disciplines that rely on the network for significant data transfer, even if the data quantities are modest compared to projects like the LHC experiments. These issues are what this talk will address; to wit: 1. Optical signal transport advances enabling 100 Gb/s circuits that span the globe on optical fiber with each carrying 100 such channels; 2. Network router and switch requirements to support high-speed international data transfer; 3. Data transport (TCP is still the norm) requirements to support high-speed international data transfer (e.g. error-free transmission); 4. Network monitoring and testing techniques and infrastructure to maintain the required error-free operation of the many R&E networks involved in international collaborations; 5. Operating system evolution to support very high-speed network I/O; 6. New network architectures and services in the LAN (campus) and WAN networks to support data-intensive science; 7. Data movement and management techniques and software that can maximize the throughput on the network connections between distributed data handling systems, and; 8. New approaches to widely distributed workflow systems that can support the data movement and analysis required by the science. All of these areas must be addressed to enable large-scale, widely distributed data analysis systems, and the experience of the LHC can be applied to other scientific disciplines. In particular, specific analogies to the SKA will be cited in the talk.

  8. High fidelity wireless network evaluation for heterogeneous cognitive radio networks

    NASA Astrophysics Data System (ADS)

    Ding, Lei; Sagduyu, Yalin; Yackoski, Justin; Azimi-Sadjadi, Babak; Li, Jason; Levy, Renato; Melodia, Tammaso

    2012-06-01

    We present a high fidelity cognitive radio (CR) network emulation platform for wireless system tests, measure- ments, and validation. This versatile platform provides the configurable functionalities to control and repeat realistic physical channel effects in integrated space, air, and ground networks. We combine the advantages of scalable simulation environment with reliable hardware performance for high fidelity and repeatable evaluation of heterogeneous CR networks. This approach extends CR design only at device (software-defined-radio) or lower-level protocol (dynamic spectrum access) level to end-to-end cognitive networking, and facilitates low-cost deployment, development, and experimentation of new wireless network protocols and applications on frequency- agile programmable radios. Going beyond the channel emulator paradigm for point-to-point communications, we can support simultaneous transmissions by network-level emulation that allows realistic physical-layer inter- actions between diverse user classes, including secondary users, primary users, and adversarial jammers in CR networks. In particular, we can replay field tests in a lab environment with real radios perceiving and learning the dynamic environment thereby adapting for end-to-end goals over distributed spectrum coordination channels that replace the common control channel as a single point of failure. CR networks offer several dimensions of tunable actions including channel, power, rate, and route selection. The proposed network evaluation platform is fully programmable and can reliably evaluate the necessary cross-layer design solutions with configurable op- timization space by leveraging the hardware experiments to represent the realistic effects of physical channel, topology, mobility, and jamming on spectrum agility, situational awareness, and network resiliency. We also provide the flexibility to scale up the test environment by introducing virtual radios and establishing seamless signal-level interactions with real radios. This holistic wireless evaluation approach supports a large-scale, het- erogeneous, and dynamic CR network architecture and allows developing cross-layer network protocols under high fidelity, repeatable, and scalable wireless test scenarios suitable for heterogeneous space, air, and ground networks.

  9. Cross layer optimization for cloud-based radio over optical fiber networks

    NASA Astrophysics Data System (ADS)

    Shao, Sujie; Guo, Shaoyong; Qiu, Xuesong; Yang, Hui; Meng, Luoming

    2016-07-01

    To adapt the 5G communication, the cloud radio access network is a paradigm introduced by operators which aggregates all base stations computational resources into a cloud BBU pool. The interaction between RRH and BBU or resource schedule among BBUs in cloud have become more frequent and complex with the development of system scale and user requirement. It can promote the networking demand among RRHs and BBUs, and force to form elastic optical fiber switching and networking. In such network, multiple stratum resources of radio, optical and BBU processing unit have interweaved with each other. In this paper, we propose a novel multiple stratum optimization (MSO) architecture for cloud-based radio over optical fiber networks (C-RoFN) with software defined networking. Additionally, a global evaluation strategy (GES) is introduced in the proposed architecture. MSO can enhance the responsiveness to end-to-end user demands and globally optimize radio frequency, optical spectrum and BBU processing resources effectively to maximize radio coverage. The feasibility and efficiency of the proposed architecture with GES strategy are experimentally verified on OpenFlow-enabled testbed in terms of resource occupation and path provisioning latency.

  10. Cross stratum resources protection in fog-computing-based radio over fiber networks for 5G services

    NASA Astrophysics Data System (ADS)

    Guo, Shaoyong; Shao, Sujie; Wang, Yao; Yang, Hui

    2017-09-01

    In order to meet the requirement of internet of things (IoT) and 5G, the cloud radio access network is a paradigm which converges all base stations computational resources into a cloud baseband unit (BBU) pool, while the distributed radio frequency signals are collected by remote radio head (RRH). A precondition for centralized processing in the BBU pool is an interconnection fronthaul network with high capacity and low delay. However, it has become more complex and frequent in the interaction between RRH and BBU and resource scheduling among BBUs in cloud. Cloud radio over fiber network has been proposed in our previous work already. In order to overcome the complexity and latency, in this paper, we first present a novel cross stratum resources protection (CSRP) architecture in fog-computing-based radio over fiber networks (F-RoFN) for 5G services. Additionally, a cross stratum protection (CSP) scheme considering the network survivability is introduced in the proposed architecture. The CSRP with CSP scheme can effectively pull the remote processing resource locally to implement the cooperative radio resource management, enhance the responsiveness and resilience to the dynamic end-to-end 5G service demands, and globally optimize optical network, wireless and fog resources. The feasibility and efficiency of the proposed architecture with CSP scheme are verified on our software defined networking testbed in terms of service latency, transmission success rate, resource occupation rate and blocking probability.

  11. A multidisciplinary monitoring network at Mayon volcano, Philippines: A collaborative effort between PHIVOLCS and EOS

    NASA Astrophysics Data System (ADS)

    Schwandner, F. M.; Hidayat, D.; Laguerta, E. P.; Baloloy, A. V.; Valerio, R.; Vaquilar, R.; Arpa, M. C.; Marcial, S. S.; Novianti, M. L.

    2012-04-01

    Mount Mayon in Albay province (Philippines) is an openly-degassing basaltic-andesitic stratovolcano, located on the northern edge of the northwest-trending OAS graben. Its latest eruptions were in Aug-Sept 2006 and Dec 2009. Mayon's current status is PHIVOLCS' level 1 with low seismicity dominated mostly local and regional tectonic earthquakes and continuous emission of SO2 from its summit crater. A research collaboration between the Earth Observatory of Singapore-NTU and the Philippine Institute of Volcanology and Seismology (PHIVOLCS) was initiated in 2009, aimed at developing a multi-disciplinary monitoring network around Mayon. The network design comprises a network of co-located geophysical, geochemical, hydrological and meteorological sensors, in both radial and circular arrangements. Radially arranged stations are intended to capture and distinguish vertical conduit processes, while the circular station design (including existing PHIVOLCS stations in cooperation with JICA, Japan) is meant to distinguish locations and sector activity of subsurface events. Geophysical instrumentation from EOS currently includes 4 broadband seismographs (in addition to 3 existing broadbands and 3 short period instruments from PHIVOLCS & JICA), and 5 tiltmeters. Four continuous cGPS stations will be installed in 2012, complementing 5 existing PHIVOLCS stations. Stations are also designed to house a multi-sensor package of static subsurface soil CO2 monitoring stations, the first of which was installed in early 2012, and which include subsoil sensors for heat flux, temperature, and moisture, as well as meteorological stations (with sonic anemometers and contact rain gages). These latter sensors are all controlled from one control box per station. Meteorological stations will help us to validate tilt, gas permeability, and also know lahar initiation potential. Since early 2011, separate stations downwind of the two prevailing wind directions from the summit continuously monitor the SO2 plume during daylight (the first Asian NOVAC dual-channel mini-DOAS). One unused agricultural well and one boxed spring were equipped with multi-sensor probes, installed in spring and summer 2011, to detect bulk volumetric strain and changes in chemical composition in high-gain and low-gain mode. All stations are autonomous in terms of their power source (solar), and are designed to withstand typhoons, break-in attempts and direct/indirect lightning strikes. To telemeter the data from these instruments to the local PHIVOLCS observatory at Lignon Hill (Legazpi), we use spread-spectrum radios with our own repeater stations, GSM/GPRS radio modems, and 3G broadband Internet. High rate data including seismic and NOVAC SO2 data are transmitted via spread-spectrum radio, whereas tilt, ground CO2, meteorology, hydrology and soil parameters are transmitted via 3G and SMS. We designed a low-cost datalogger system, which has been operating since Jan 2011, performing continuous data acquisition with sampling rate of 20 minute/sample and transmitted through GSM network, for tilt data. The receiving station is the PHIVOLCS Lignon Hill Observatory (LHO), where an off-grid power system has been installed to ensure continuous operation of the monitoring computers and radios. Local pre-processing by observatory staff and local archiving ensures close to immediate availability of data products in times of crisis. The data are also forwarded via TCP/IP to servers at PHIVOLCS headquarters and at EOS. Network infrastructure and data flows will be completed in 2012.

  12. 77 FR 16800 - Radio Broadcasting Services; Dermott, AR, and Cleveland, MS

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-03-22

    ... FEDERAL COMMUNICATIONS COMMISSION 47 CFR Part 73 [MB Docket No. 12-53; RM-11658; DA 12-328] Radio... petition filed by Delta Radio Network, LLC, proposing to amend the Table of Allotments by substituting..., interested parties should serve petitioner as follows: Larry J. Fuss, President, Delta Radio Network, LLC...

  13. CMS Centres Worldwide - a New Collaborative Infrastructure

    NASA Astrophysics Data System (ADS)

    Taylor, Lucas

    2011-12-01

    The CMS Experiment at the LHC has established a network of more than fifty inter-connected "CMS Centres" at CERN and in institutes in the Americas, Asia, Australasia, and Europe. These facilities are used by people doing CMS detector and computing grid operations, remote shifts, data quality monitoring and analysis, as well as education and outreach. We present the computing, software, and collaborative tools and videoconferencing systems. These include permanently running "telepresence" video links (hardware-based H.323, EVO and Vidyo), Webcasts, and generic Web tools such as CMS-TV for broadcasting live monitoring and outreach information. Being Web-based and experiment-independent, these systems could easily be extended to other organizations. We describe the experiences of using CMS Centres Worldwide in the CMS data-taking operations as well as for major media events with several hundred TV channels, radio stations, and many more press journalists simultaneously around the world.

  14. Analysis of interference performance of tactical radio network

    NASA Astrophysics Data System (ADS)

    Nie, Hao; Cai, Xiaoxia; Chen, Hong

    2017-08-01

    Mobile Ad hoc network has a strong military background for its development as the core technology of the backbone network of US tactical Internet. And which tactical radio network, is the war in today's tactical use of the Internet more mature form of networking, mainly used in brigade and brigade following forces. This paper analyzes the typical protocol AODV in the tactical radio network, and then carries on the networking. By adding the interference device to the whole network, the battlefield environment is simulated, and then the throughput, delay and packet loss rate are analyzed, and the performance of the whole network and the single node before and after the interference is obtained.

  15. The NOIRE Study

    NASA Astrophysics Data System (ADS)

    Cecconi, B.; Laurens, A.; Briand, C.; Girard, J.; Bucher, M.; Puy, D.; Segret, B.; Bentum, M.

    2016-12-01

    NOIRE (Nanosats pour un Observatoire Interférométrique Radio dans l'Espace; Nanosats for a space borne interferometric radio observatory) is an ongoing feasibility study with CNES and in collaboration with Dutch colleagues. The goal is to assess the feasibility of a low frequency space radio interferometer using nanosatellites.

  16. Experimental demonstration of multi-dimensional resources integration for service provisioning in cloud radio over fiber network

    NASA Astrophysics Data System (ADS)

    Yang, Hui; Zhang, Jie; Ji, Yuefeng; He, Yongqi; Lee, Young

    2016-07-01

    Cloud radio access network (C-RAN) becomes a promising scenario to accommodate high-performance services with ubiquitous user coverage and real-time cloud computing in 5G area. However, the radio network, optical network and processing unit cloud have been decoupled from each other, so that their resources are controlled independently. Traditional architecture cannot implement the resource optimization and scheduling for the high-level service guarantee due to the communication obstacle among them with the growing number of mobile internet users. In this paper, we report a study on multi-dimensional resources integration (MDRI) for service provisioning in cloud radio over fiber network (C-RoFN). A resources integrated provisioning (RIP) scheme using an auxiliary graph is introduced based on the proposed architecture. The MDRI can enhance the responsiveness to dynamic end-to-end user demands and globally optimize radio frequency, optical network and processing resources effectively to maximize radio coverage. The feasibility of the proposed architecture is experimentally verified on OpenFlow-based enhanced SDN testbed. The performance of RIP scheme under heavy traffic load scenario is also quantitatively evaluated to demonstrate the efficiency of the proposal based on MDRI architecture in terms of resource utilization, path blocking probability, network cost and path provisioning latency, compared with other provisioning schemes.

  17. Experimental demonstration of multi-dimensional resources integration for service provisioning in cloud radio over fiber network.

    PubMed

    Yang, Hui; Zhang, Jie; Ji, Yuefeng; He, Yongqi; Lee, Young

    2016-07-28

    Cloud radio access network (C-RAN) becomes a promising scenario to accommodate high-performance services with ubiquitous user coverage and real-time cloud computing in 5G area. However, the radio network, optical network and processing unit cloud have been decoupled from each other, so that their resources are controlled independently. Traditional architecture cannot implement the resource optimization and scheduling for the high-level service guarantee due to the communication obstacle among them with the growing number of mobile internet users. In this paper, we report a study on multi-dimensional resources integration (MDRI) for service provisioning in cloud radio over fiber network (C-RoFN). A resources integrated provisioning (RIP) scheme using an auxiliary graph is introduced based on the proposed architecture. The MDRI can enhance the responsiveness to dynamic end-to-end user demands and globally optimize radio frequency, optical network and processing resources effectively to maximize radio coverage. The feasibility of the proposed architecture is experimentally verified on OpenFlow-based enhanced SDN testbed. The performance of RIP scheme under heavy traffic load scenario is also quantitatively evaluated to demonstrate the efficiency of the proposal based on MDRI architecture in terms of resource utilization, path blocking probability, network cost and path provisioning latency, compared with other provisioning schemes.

  18. Performance evaluation of multi-stratum resources optimization with network functions virtualization for cloud-based radio over optical fiber networks.

    PubMed

    Yang, Hui; He, Yongqi; Zhang, Jie; Ji, Yuefeng; Bai, Wei; Lee, Young

    2016-04-18

    Cloud radio access network (C-RAN) has become a promising scenario to accommodate high-performance services with ubiquitous user coverage and real-time cloud computing using cloud BBUs. In our previous work, we implemented cross stratum optimization of optical network and application stratums resources that allows to accommodate the services in optical networks. In view of this, this study extends to consider the multiple dimensional resources optimization of radio, optical and BBU processing in 5G age. We propose a novel multi-stratum resources optimization (MSRO) architecture with network functions virtualization for cloud-based radio over optical fiber networks (C-RoFN) using software defined control. A global evaluation scheme (GES) for MSRO in C-RoFN is introduced based on the proposed architecture. The MSRO can enhance the responsiveness to dynamic end-to-end user demands and globally optimize radio frequency, optical and BBU resources effectively to maximize radio coverage. The efficiency and feasibility of the proposed architecture are experimentally demonstrated on OpenFlow-based enhanced SDN testbed. The performance of GES under heavy traffic load scenario is also quantitatively evaluated based on MSRO architecture in terms of resource occupation rate and path provisioning latency, compared with other provisioning scheme.

  19. Experimental demonstration of multi-dimensional resources integration for service provisioning in cloud radio over fiber network

    PubMed Central

    Yang, Hui; Zhang, Jie; Ji, Yuefeng; He, Yongqi; Lee, Young

    2016-01-01

    Cloud radio access network (C-RAN) becomes a promising scenario to accommodate high-performance services with ubiquitous user coverage and real-time cloud computing in 5G area. However, the radio network, optical network and processing unit cloud have been decoupled from each other, so that their resources are controlled independently. Traditional architecture cannot implement the resource optimization and scheduling for the high-level service guarantee due to the communication obstacle among them with the growing number of mobile internet users. In this paper, we report a study on multi-dimensional resources integration (MDRI) for service provisioning in cloud radio over fiber network (C-RoFN). A resources integrated provisioning (RIP) scheme using an auxiliary graph is introduced based on the proposed architecture. The MDRI can enhance the responsiveness to dynamic end-to-end user demands and globally optimize radio frequency, optical network and processing resources effectively to maximize radio coverage. The feasibility of the proposed architecture is experimentally verified on OpenFlow-based enhanced SDN testbed. The performance of RIP scheme under heavy traffic load scenario is also quantitatively evaluated to demonstrate the efficiency of the proposal based on MDRI architecture in terms of resource utilization, path blocking probability, network cost and path provisioning latency, compared with other provisioning schemes. PMID:27465296

  20. THE POSITION/STRUCTURE STABILITY OF FOUR ICRF2 SOURCES

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Fomalont, Ed; Johnston, Kenneth; Fey, Alan

    2011-03-15

    Four close radio sources in the International Celestial Reference Frame (ICRF) catalog were observed using phase referencing with the VLBA at 43, 23, and 8.6 GHz, and with VERA at 23 GHz over a one-year period. The goal was to determine the stability of the radio cores and to assess structure effects associated with positions in the ICRF. Although the four sources were compact at 8.6 GHz, the VLBA images at 43 GHz with 0.3 mas resolution showed that all were composed of several components. A component in each source was identified as the radio core using some or allmore » of the following emission properties: compactness, spectral index, location at the end of the extended emission region, and stationary in the sky. Over the observing period, the relative positions between the four radio cores were constant to 0.02 mas, the phase-referencing positional accuracy obtained at 23 and 43 GHz among the sources, suggesting that once a radio core is identified, it remains stationary in the sky to this accuracy. Other radio components in two of the four sources had detectable motion in the radio jet direction. Comparison of the 23 and 43 GHz VLBA images with the VLBA 8.6 GHz images and the ICRF positions suggests that some ICRF positions are dominated by a moving jet component; hence, they can be displaced up to 0.5 mas from the radio core and may also reflect the motion of the jet component. Future astrometric efforts to determine a more accurate quasar reference frame at 23 and 43 GHz and from the VLBI2010 project are discussed, and supporting VLBA or European VLBI Network observations of ICRF sources at 43 GHz are recommended in order to determine the internal structure of the sources. A future collaboration between the radio (ICRF) and the optical frame of GAIA is discussed.« less

  1. Unveiling the radio cosmos

    NASA Astrophysics Data System (ADS)

    Vanderlinde, Keith

    2017-02-01

    Using a radio telescope with no moving parts, the dark energy speeding up the expansion of the Universe can be probed in unprecedented detail, says Keith Vanderlinde, on behalf of the CHIME collaboration.

  2. An Approach to Command and Control Using Emerging Technologies

    DTIC Science & Technology

    2013-06-01

    communicating in disadvantaged networks like fielded tactical radio networks. With the emergence and proliferation of new tactical radios capable of...undesirable, particularly on disadvantaged radio links, so in the return CoT message HTTP links are provided so the client may download the chips

  3. Performance Analysis of Optical Mobile Fronthaul for Cloud Radio Access Networks

    NASA Astrophysics Data System (ADS)

    Zhang, Jiawei; Xiao, Yuming; Li, Hui; Ji, Yuefeng

    2017-10-01

    Cloud radio access networks (C-RAN) separates baseband units (BBU) of conventional base station to a centralized pool which connects remote radio heads (RRH) through mobile fronthaul. Mobile fronthaul is a new network segment of C-RAN, it is designed to transport digital sampling data between BBU and RRH. Optical transport networks that provide large bandwidth and low latency is a promising fronthaul solution. In this paper, we discuss several optical transport networks which are candidates for mobile fronthaul, analyze their performances including the number of used wavelength, round-trip latency and wavelength utilization.

  4. A radio-aware routing algorithm for reliable directed diffusion in lossy wireless sensor networks.

    PubMed

    Kim, Yong-Pyo; Jung, Euihyun; Park, Yong-Jin

    2009-01-01

    In Wireless Sensor Networks (WSNs), transmission errors occur frequently due to node failure, battery discharge, contention or interference by objects. Although Directed Diffusion has been considered as a prominent data-centric routing algorithm, it has some weaknesses due to unexpected network errors. In order to address these problems, we proposed a radio-aware routing algorithm to improve the reliability of Directed Diffusion in lossy WSNs. The proposed algorithm is aware of the network status based on the radio information from MAC and PHY layers using a cross-layer design. The cross-layer design can be used to get detailed information about current status of wireless network such as a link quality or transmission errors of communication links. The radio information indicating variant network conditions and link quality was used to determine an alternative route that provides reliable data transmission under lossy WSNs. According to the simulation result, the radio-aware reliable routing algorithm showed better performance in both grid and random topologies with various error rates. The proposed solution suggested the possibility of providing a reliable transmission method for QoS requests in lossy WSNs based on the radio-awareness. The energy and mobility issues will be addressed in the future work.

  5. Local area networking in a radio quiet environment

    NASA Astrophysics Data System (ADS)

    Childers, Edwin L.; Hunt, Gareth; Brandt, Joseph J.

    2002-11-01

    The Green Bank facility of the National Radio Astronomy Observatory is spread out over 2,700 acres in the Allegheny Mountains of West Virginia. Good communication has always been needed between the radio telescopes and the control buildings. The National Radio Quiet Zone helps protect the Green Bank site from radio transmissions that interfere with the astronomical signals. Due to stringent Radio Frequency Interference (RFI) requirements, a fiber optic communication system was used for Ethernet transmissions on the site and coaxial cable within the buildings. With the need for higher speed communications, the entire network has been upgraded to use optical fiber with modern Ethernet switches. As with most modern equipment, the implementation of the control of the newly deployed Green Bank Telescope (GBT) depends heavily on TCP/IP. In order to protect the GBT from the commodity Internet, the GBT uses a non-routable network. Communication between the control building Local Area Network (LAN) and the GBT is implemented using a Virtual LAN (VLAN). This configuration will be extended to achieve isolation between trusted local user systems, the GBT, and other Internet users. Legitimate access to the site, for example by remote observers, is likely to be implemented using a virtual private network (VPN).

  6. Indoor radio measurement and planning for UMTS/HSDPA with antennas

    NASA Astrophysics Data System (ADS)

    Eheduru, Marcellinus

    Over the last decade, mobile communication networks have evolved tremendously with a key focus on providing high speed data services in addition to voice. The third generation of mobile networks in the form of Universal Mobile Telecommunications System (UMTS) is already offering revolutionary mobile broadband experience to its users by deploying High Speed Downlink Packet Access (HSDPA) as its packet-data technology. With data speeds up to 14.4 Mbps and ubiquitous mobility, HSDPA is anticipated to become a preferred broadband access medium for end-users via mobile phones, laptops etc. While majority of these end-users are located indoors most of the time, approximately 70-80% of the HSDPA traffic is estimated to originate from inside buildings. Thus for network operators, indoor coverage has become a necessity for technical and business reasons. Macro-cellular (outdoor) to indoor coverage is a natural inexpensive way of providing network coverage inside the buildings. However, it does not guarantee sufficient link quality required for optimal HSDPA operation. On the contrary, deploying a dedicated indoor system may be far too expensive from an operator's point of view. In this thesis, the concept is laid for the understanding of indoor radio wave propagation in a campus building environment which could be used to plan and improve outdoor-to-indoor UMTS/HSDPA radio propagation performance. It will be shown that indoor range performance depends not only on the transmit power of an indoor antenna, but also on the product's response to multipath and obstructions in the environment along the radio propagation path. An extensive measurement campaign will be executed in different indoor environments analogous to easy, medium and hard radio conditions. The effects of walls, ceilings, doors and other obstacles on measurement results would be observed. Chapter one gives a brief introduction to the evolution of UMTS and HSDPA. It goes on to talk about radio wave propagation and some important properties of antennas which must be considered when choosing an antenna for indoor radio propagation. The challenges of in-building network coverage and also the objectives of this thesis are also mentioned in this chapter. The evolution and standardization, network architecture, radio features and most importantly, the radio resource management features of UMTS/HSDPA are given in chapter two. In this chapter, the reason why Wideband Code Division Multiple Access (WCDMA) was specified and selected for 3G (UMTS) systems would be seen. The architecture of the radio access network, interfaces with the radio access network between base stations and radio network controllers (RNC), and the interface between the radio access network and the core network are also described in this chapter. The main features of HSDPA are mentioned at the end of the chapter. In chapter three the principles of the WCDMA air interface, including spreading, Rake reception, signal fading, power control and handovers are introduced. The different types and characteristics of the propagation environments and how they influence radio wave propagation are mentioned. UMTS transport, logical and physical channels are also mentioned, highlighting their significance and relationship in and with the network. Radio network planning for UMTS is discussed in chapter four. The outdoor planning process which includes dimensioning, detailed planning, optimization and monitoring is outlined. Indoor radio planning with distributed antenna systems (DAS), which is the idea and motivation behind this thesis work, is also discussed. The various antennas considered and the antenna that was selected for this thesis experiment was discussed in chapter five. The antenna radiation pattern, directivity, gain and input impedance were the properties of the antenna that were taken into consideration. The importance of the choice of the antenna for any particular type of indoor environment is also mentioned. In chapter six, the design and fabrication of the monopole antennas used for the experimental measurement is mentioned. The procedure for measurement and the equipment used are also discussed. The results gotten from the experiment are finally analyzed and discussed. In this chapter the effect of walls, floors, doors, ceilings and other obstacles on radio wave propagation will be seen. Finally, chapter seven concludes this thesis work and gives some directions for future work.

  7. A Bibliography of Packet Radio Literature.

    DTIC Science & Technology

    1984-03-01

    r r* C.C.4. W . . . . . . . . .. . . . Gafni, E. and D. Bertsekas, "Distributed Algorithms for Generating Loop-Free Routes in Networks with Frequently...December 1980). Leiner, B., K. Klemba, and J. Tornow , "Packet Radio Networking," Computer World, pp. 26-37, 30, (September 27, 1982). Liu, J...34Distributed Routing and Relay Management in Mobile Packet Radio Networks," Proceedings IEEE COMPCON Fall 󈨔, p. 235-243 (1980). MacGregor, W ., J. Westcott, and

  8. Portable Wireless LAN Device and Two-way Radio Threat Assessment for Aircraft Navigation Radios

    NASA Technical Reports Server (NTRS)

    Nguyen, Truong X.; Koppen, Sandra V.; Ely, Jay J.; Williams, Reuben A.; Smith, Laura J.; Salud, Maria Theresa P.

    2003-01-01

    Measurement processes, data and analysis are provided to address the concern for Wireless Local Area Network devices and two-way radios to cause electromagnetic interference to aircraft navigation radio systems. A radiated emission measurement process is developed and spurious radiated emissions from various devices are characterized using reverberation chambers. Spurious radiated emissions in aircraft radio frequency bands from several wireless network devices are compared with baseline emissions from standard computer laptops and personal digital assistants. In addition, spurious radiated emission data in aircraft radio frequency bands from seven pairs of two-way radios are provided, A description of the measurement process, device modes of operation and the measurement results are reported. Aircraft interference path loss measurements were conducted on four Boeing 747 and Boeing 737 aircraft for several aircraft radio systems. The measurement approach is described and the path loss results are compared with existing data from reference documents, standards, and NASA partnerships. In-band on-channel interference thresholds are compiled from an existing reference document. Using these data, a risk assessment is provided for interference from wireless network devices and two-way radios to aircraft systems, including Localizer, Glideslope, Very High Frequency Omnidirectional Range, Microwave Landing System and Global Positioning System. The report compares the interference risks associated with emissions from wireless network devices and two-way radios against standard laptops and personal digital assistants. Existing receiver interference threshold references are identified as to require more data for better interference risk assessments.

  9. Routing to preserve energy in wireless networks

    NASA Astrophysics Data System (ADS)

    Block, Frederick J., IV

    Many applications for wireless radio networks require that some or all radios in the network rely on batteries as energy sources. In many cases, battery replacement is infeasible, expensive, or impossible. Communication protocols for such networks should be designed to preserve limited energy supplies. Because the choice of a route to a traffic sink influences how often radios must transmit and receive, poor route selection can quickly deplete the batteries of certain nodes. Previous work has shown that a network's lifetime can be extended by assigning higher routing costs to nodes with little remaining energy and nodes that must use high transmitter power to reach neighbor radios. Although using remaining energy levels in routing metrics can increase network lifetime, in practice, there may be significant error in a node's estimate of its battery level. The effect of battery level uncertainty on routing is examined. Routing metrics are presented that are designed to explicitly account for uncertainty in remaining energy. Simulation results using several statistical models for this uncertainty show that the proposed metrics perform well. In addition to knowledge of current battery levels, estimates of how quickly radios are consuming energy may be helpful in extending network lifetime. We present a family of routing metrics that incorporate a radio's rate of energy consumption. Simulation results show that the proposed family of metrics performs well under a variety of traffic models and network topologies. Route selection can also be complicated by time-varying link conditions. Radios may be subject to interference from other nearby communication systems, hostile jammers, and other, non-communication sources of noise. A route that first appears to have only a small cost may later require much greater energy expenditure when transmitting packets. Frequent route selection can help radios avoid using links with interference, but additional routing control messages increase energy consumption. We investigate the effects of time-varying interference on the lifetime of ad hoc networks. It is shown that there is a tradeoff between packet delay and node lifetime. We show that it is possible to design the system to perform well under a wide variety of channel conditions.

  10. HamSCI: The Ham Radio Science Citizen Investigation

    NASA Astrophysics Data System (ADS)

    Frissell, N. A.; Moses, M. L.; Earle, G. D.; McGwier, R. W.; Miller, E. S.; Kaeppler, S. R.; Silver, H. W.; Ceglia, F.; Pascoe, D.; Sinanis, N.; Smith, P.; Williams, R.; Shovkoplyas, A.; Gerrard, A. J.

    2016-12-01

    Amateur (or "ham") radio operators are individuals with a non-pecuniary interest in radio technology, engineering, communications, science, and public service. They are licensed by their national governments to transmit on amateur radio frequencies. In many jurisdictions, there is no age requirement for a ham radio license, and operators from diverse backgrounds participate. There are more than 740,000 hams in the US, and over 3 million (estimated) worldwide. Many amateur communications are conducted using transionospheric links and thus affected by space weather and ionospheric processes. Recent technological advances have enabled the development of automated ham radio observation networks (e.g. the Reverse Beacon Network, www.reversebeacon.net) and specialized operating modes for the study of weak-signal propagation. The data from these networks have been shown to be useful for the study of ionospheric processes. In order to connect professional researchers with the volunteer-based ham radio community, HamSCI (Ham Radio Science Citizen Investigation, www.hamsci.org) has been established. HamSCI is a platform for publicizing and promoting projects that are consistent with the following objectives: (1) Advance scientific research and understanding through amateur radio activities. (2) Encourage the development of new technologies to support this research. (3) Provide educational opportunities for the amateur community and the general public. HamSCI researchers are working with the American Radio Relay League (ARRL, www.arrl.org) to publicize these objectives and recruit interested hams. The ARRL is the US national organization for amateur radio with a membership of over 170,000 and a monthly magazine, QST. HamSCI is currently preparing to support ionospheric research connected to the 21 Aug 2017 Total Solar Eclipse by expanding coverage of the Reverse Beacon Network and organizing a large-scale ham radio operating event ("QSO Party") to generate data during the eclipse.

  11. An Examination of Application of Artificial Neural Network in Cognitive Radios

    NASA Astrophysics Data System (ADS)

    Bello Salau, H.; Onwuka, E. N.; Aibinu, A. M.

    2013-12-01

    Recent advancement in software radio technology has led to the development of smart device known as cognitive radio. This type of radio fuses powerful techniques taken from artificial intelligence, game theory, wideband/multiple antenna techniques, information theory and statistical signal processing to create an outstanding dynamic behavior. This cognitive radio is utilized in achieving diverse set of applications such as spectrum sensing, radio parameter adaptation and signal classification. This paper contributes by reviewing different cognitive radio implementation that uses artificial intelligence such as the hidden markov models, metaheuristic algorithm and artificial neural networks (ANNs). Furthermore, different areas of application of ANNs and their performance metrics based approach are also examined.

  12. The TF1 Radio Astronomy Working Group in the Andean ROAD: goals and challenges for 2025

    NASA Astrophysics Data System (ADS)

    Chaparro Molano, G.

    2017-07-01

    Since the creation of the Andean Regional Office of Astronomy for Development (OAD) of the International Astronomical Union, one of the main goals has been to foster a scientific culture of radio astronomy in countries of the central and northern Andes (Bolivia, Colombia, Ecuador, Perú, and Venezuela). For this reason, Andean ROAD Task Force 1 (Research and Education in Universities) created the Radio Astronomy Working Group to set a path along which collaborative endeavors can grow and yield scientific results. The first official meeting of the Working Group took place in Bogotá, Colombia during the 2nd Astronomá en los Andes Workshop (2015) where scientists actively developing projects in radio astronomy set goals for the near future, such as improving mobility for researchers and students, developing collaborations in related areas such as engineering and data science, and building transnational collaborations aiming at developing VLBI across the countries of the Andean ROAD and beyond. In this poster, I present current projects and associated research groups (ROAS - Perú, SiAMo - Colombia, Alfa-Orion UTP - Colombia, RAIG - Chile) and discuss goalposts and current challenges in the development of transnational radioastronomical projects. As a case study, I present the development and early astronomical results of the privately funded UECCI 4m Radio Telescope for 21 cm line observations in Bogotá, Colombia.

  13. 75 FR 32508 - Harris Stratex Networks Corporation, Currently Known As Aviat U.S., Inc., dba Aviat Networks, Inc...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-06-08

    ... workers of the subject firm. The workers were engaged in the production of Truepoint 5000 XCVR microwave radios and are separately identifiable from workers producing other microwave radios. New information... Division, engaged in employment related to the production of Truepoint 5000 XCVR microwave radios...

  14. tf_unet: Generic convolutional neural network U-Net implementation in Tensorflow

    NASA Astrophysics Data System (ADS)

    Akeret, Joel; Chang, Chihway; Lucchi, Aurelien; Refregier, Alexandre

    2016-11-01

    tf_unet mitigates radio frequency interference (RFI) signals in radio data using a special type of Convolutional Neural Network, the U-Net, that enables the classification of clean signal and RFI signatures in 2D time-ordered data acquired from a radio telescope. The code is not tied to a specific segmentation and can be used, for example, to detect radio frequency interference (RFI) in radio astronomy or galaxies and stars in widefield imaging data. This U-Net implementation can outperform classical RFI mitigation algorithms.

  15. GPs’ use of defibrillators and the national radio network in emergency primary healthcare in Norway

    PubMed Central

    Zakariassen, Erik; Hunskaar, Steinar

    2008-01-01

    Objective To study the geographic size of out-of-hours districts, the availability of defibrillators and use of the national radio network in Norway. Design Survey. Setting The emergency primary healthcare system in Norway. Subjects A total of 282 host municipalities responsible for 260 out-of-hours districts. Main outcome measures Size of out-of-hours districts, use of national radio network and access to a defibrillator in emergency situations. Results The out-of-hours districts have a wide range of areas, which gives a large variation in driving time for doctors on call. The median longest transport time for doctors in Norway is 45 minutes. In 46% of out-of-hours districts doctors bring their own defibrillator on emergency callouts. Doctors always use the national radio network in 52% of out-of-hours districts. Use of the radio network and access to a defibrillator are significantly greater in out-of-hours districts with a host municipality of fewer then 5000 inhabitants compared with host municipalities of more than 20 000 inhabitants. Conclusion In half of out-of-hours districts doctors on call always use the national radio network. Doctors in out-of-hours districts with a host municipality of fewer than 5000 inhabitants are in a better state of readiness to attend an emergency, compared with doctors working in larger host municipalities. PMID:18570012

  16. FIRESTORM: a collaborative network suite application for rapid sensor data processing and precise decisive responses

    NASA Astrophysics Data System (ADS)

    Kaniyantethu, Shaji

    2011-06-01

    This paper discusses the many features and composed technologies in Firestorm™ - a Distributed Collaborative Fires and Effects software. Modern response management systems capitalize on the capabilities of a plethora of sensors and its output for situational awareness. Firestorm utilizes a unique networked lethality approach by integrating unmanned air and ground vehicles to provide target handoff and sharing of data between humans and sensors. The system employs Bayesian networks for track management of sensor data, and distributed auction algorithms for allocating targets and delivering the right effect without information overload to the Warfighter. Firestorm Networked Effects Component provides joint weapon-target pairing, attack guidance, target selection standards, and other fires and effects components. Moreover, the open and modular architecture allows for easy integration with new data sources. Versatility and adaptability of the application enable it to devise and dispense a suitable response to a wide variety of scenarios. Recently, this application was used for detecting and countering a vehicle intruder with the help of radio frequency spotter sensor, command driven cameras, remote weapon system, portable vehicle arresting barrier, and an unmanned aerial vehicle - which confirmed the presence of the intruder, as well as provided lethal/non-lethal response and battle damage assessment. The completed demonstrations have proved Firestorm's™ validity and feasibility to predict, detect, neutralize, and protect key assets and/or area against a variety of possible threats. The sensors and responding assets can be deployed with numerous configurations to cover the various terrain and environmental conditions, and can be integrated to a number of platforms.

  17. 47 CFR 73.4154 - Network/AM, FM station affiliation agreements.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 47 Telecommunication 4 2011-10-01 2011-10-01 false Network/AM, FM station affiliation agreements. 73.4154 Section 73.4154 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) BROADCAST RADIO SERVICES RADIO BROADCAST SERVICES Rules Applicable to All Broadcast Stations § 73.4154 Network/AM...

  18. 47 CFR 73.4154 - Network/AM, FM station affiliation agreements.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 47 Telecommunication 4 2010-10-01 2010-10-01 false Network/AM, FM station affiliation agreements. 73.4154 Section 73.4154 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) BROADCAST RADIO SERVICES RADIO BROADCAST SERVICES Rules Applicable to All Broadcast Stations § 73.4154 Network/AM...

  19. Radio frequency interference mitigation using deep convolutional neural networks

    NASA Astrophysics Data System (ADS)

    Akeret, J.; Chang, C.; Lucchi, A.; Refregier, A.

    2017-01-01

    We propose a novel approach for mitigating radio frequency interference (RFI) signals in radio data using the latest advances in deep learning. We employ a special type of Convolutional Neural Network, the U-Net, that enables the classification of clean signal and RFI signatures in 2D time-ordered data acquired from a radio telescope. We train and assess the performance of this network using the HIDE &SEEK radio data simulation and processing packages, as well as early Science Verification data acquired with the 7m single-dish telescope at the Bleien Observatory. We find that our U-Net implementation is showing competitive accuracy to classical RFI mitigation algorithms such as SEEK's SUMTHRESHOLD implementation. We publish our U-Net software package on GitHub under GPLv3 license.

  20. Collaborative Beamfocusing Radio (COBRA)

    NASA Astrophysics Data System (ADS)

    Rode, Jeremy P.; Hsu, Mark J.; Smith, David; Husain, Anis

    2013-05-01

    A Ziva team has recently demonstrated a novel technique called Collaborative Beamfocusing Radios (COBRA) which enables an ad-hoc collection of distributed commercial off-the-shelf software defined radios to coherently align and beamform to a remote radio. COBRA promises to operate even in high multipath and non-line-of-sight environments as well as mobile applications without resorting to computationally expensive closed loop techniques that are currently unable to operate with significant movement. COBRA exploits two key technologies to achieve coherent beamforming. The first is Time Reversal (TR) which compensates for multipath and automatically discovers the optimal spatio-temporal matched filter to enable peak signal gains (up to 20 dB) and diffraction-limited focusing at the intended receiver in NLOS and severe multipath environments. The second is time-aligned buffering which enables TR to synchronize distributed transmitters into a collaborative array. This time alignment algorithm avoids causality violations through the use of reciprocal buffering. Preserving spatio-temporal reciprocity through the TR capture and retransmission process achieves coherent alignment across multiple radios at ~GHz carriers using only standard quartz-oscillators. COBRA has been demonstrated in the lab, aligning two off-the-shelf software defined radios over-the-air to an accuracy of better than 2 degrees of carrier alignment at 450 MHz. The COBRA algorithms are lightweight, with computation in 5 ms on a smartphone class microprocessor. COBRA also has low start-up latency, achieving high accuracy from a cold-start in 30 ms. The COBRA technique opens up a large number of new capabilities in communications, and electronic warfare including selective spatial jamming, geolocation and anti-geolocation.

  1. An Energy-Efficient Game-Theory-Based Spectrum Decision Scheme for Cognitive Radio Sensor Networks

    PubMed Central

    Salim, Shelly; Moh, Sangman

    2016-01-01

    A cognitive radio sensor network (CRSN) is a wireless sensor network in which sensor nodes are equipped with cognitive radio. In this paper, we propose an energy-efficient game-theory-based spectrum decision (EGSD) scheme for CRSNs to prolong the network lifetime. Note that energy efficiency is the most important design consideration in CRSNs because it determines the network lifetime. The central part of the EGSD scheme consists of two spectrum selection algorithms: random selection and game-theory-based selection. The EGSD scheme also includes a clustering algorithm, spectrum characterization with a Markov chain, and cluster member coordination. Our performance study shows that EGSD outperforms the existing popular framework in terms of network lifetime and coordination overhead. PMID:27376290

  2. An Energy-Efficient Game-Theory-Based Spectrum Decision Scheme for Cognitive Radio Sensor Networks.

    PubMed

    Salim, Shelly; Moh, Sangman

    2016-06-30

    A cognitive radio sensor network (CRSN) is a wireless sensor network in which sensor nodes are equipped with cognitive radio. In this paper, we propose an energy-efficient game-theory-based spectrum decision (EGSD) scheme for CRSNs to prolong the network lifetime. Note that energy efficiency is the most important design consideration in CRSNs because it determines the network lifetime. The central part of the EGSD scheme consists of two spectrum selection algorithms: random selection and game-theory-based selection. The EGSD scheme also includes a clustering algorithm, spectrum characterization with a Markov chain, and cluster member coordination. Our performance study shows that EGSD outperforms the existing popular framework in terms of network lifetime and coordination overhead.

  3. Collaborative visual analytics of radio surveys in the Big Data era

    NASA Astrophysics Data System (ADS)

    Vohl, Dany; Fluke, Christopher J.; Hassan, Amr H.; Barnes, David G.; Kilborn, Virginia A.

    2017-06-01

    Radio survey datasets comprise an increasing number of individual observations stored as sets of multidimensional data. In large survey projects, astronomers commonly face limitations regarding: 1) interactive visual analytics of sufficiently large subsets of data; 2) synchronous and asynchronous collaboration; and 3) documentation of the discovery workflow. To support collaborative data inquiry, we present encube, a large-scale comparative visual analytics framework. encube can utilise advanced visualization environments such as the CAVE2 (a hybrid 2D and 3D virtual reality environment powered with a 100 Tflop/s GPU-based supercomputer and 84 million pixels) for collaborative analysis of large subsets of data from radio surveys. It can also run on standard desktops, providing a capable visual analytics experience across the display ecology. encube is composed of four primary units enabling compute-intensive processing, advanced visualisation, dynamic interaction, parallel data query, along with data management. Its modularity will make it simple to incorporate astronomical analysis packages and Virtual Observatory capabilities developed within our community. We discuss how encube builds a bridge between high-end display systems (such as CAVE2) and the classical desktop, preserving all traces of the work completed on either platform - allowing the research process to continue wherever you are.

  4. Hierarchical Organization for Large, Dynamic Radio Networks.

    DTIC Science & Technology

    1988-01-01

    January 1985. [3] N. Shacharm and J. Tornow . Future Directions in Packet Radio Technology. In - Proc. of IEEE INFOCOM󈨙, Washington, D.C., 1985. [4] J.J...Freeman and Company, 1979. [7] J. Jubin and J. Tornow . The DARPA Packet Radio Network Protocols. Proceed- inga of the IEEE, 75(1):21-32, January 1987... Tornow . Future Directions in Packet Radio Technology. In Proc. of IEEE INFOCOM󈨙, Washington, D.C., 1985. [28] N. Shacham and J. Westcott. Future

  5. Properties of centralized cooperative sensing in cognitive radio networks

    NASA Astrophysics Data System (ADS)

    Skokowski, Paweł; Malon, Krzysztof; Łopatka, Jerzy

    2017-04-01

    Spectrum sensing is a functionality that enables network creation in the cognitive radio technology. Spectrum sensing is use for building the situation awareness knowledge for better use of radio resources and to adjust network parameters in case of jamming, interferences from legacy systems, decreasing link quality caused e.g. by nodes positions changes. This paper presents results from performed tests to compare cooperative centralized sensing versus local sensing. All tests were performed in created simulator developed in Matlab/Simulink environment.

  6. A Method of the UMTS-FDD Network Design Based on Universal Load Characteristics

    NASA Astrophysics Data System (ADS)

    Gajewski, Slawomir

    In the paper an original method of the UMTS radio network design was presented. The method is based on simple way of capacity-coverage trade-off estimation for WCDMA/FDD radio interface. This trade-off is estimated by using universal load characteristics and normalized coverage characteristics. The characteristics are useful for any propagation environment as well as for any service performance requirements. The practical applications of these characteristics on radio network planning and maintenance were described.

  7. Assessing Routing Strategies for Cognitive Radio Sensor Networks

    PubMed Central

    Zubair, Suleiman; Fisal, Norsheila; Baguda, Yakubu S.; Saleem, Kashif

    2013-01-01

    Interest in the cognitive radio sensor network (CRSN) paradigm has gradually grown among researchers. This concept seeks to fuse the benefits of dynamic spectrum access into the sensor network, making it a potential player in the next generation (NextGen) network, which is characterized by ubiquity. Notwithstanding its massive potential, little research activity has been dedicated to the network layer. By contrast, we find recent research trends focusing on the physical layer, the link layer and the transport layers. The fact that the cross-layer approach is imperative, due to the resource-constrained nature of CRSNs, can make the design of unique solutions non-trivial in this respect. This paper seeks to explore possible design opportunities with wireless sensor networks (WSNs), cognitive radio ad-hoc networks (CRAHNs) and cross-layer considerations for implementing viable CRSN routing solutions. Additionally, a detailed performance evaluation of WSN routing strategies in a cognitive radio environment is performed to expose research gaps. With this work, we intend to lay a foundation for developing CRSN routing solutions and to establish a basis for future work in this area. PMID:24077319

  8. Hybrid Mobile Communication Networks for Planetary Exploration

    NASA Technical Reports Server (NTRS)

    Alena, Richard; Lee, Charles; Walker, Edward; Osenfort, John; Stone, Thom

    2007-01-01

    A paper discusses the continuing work of the Mobile Exploration System Project, which has been performing studies toward the design of hybrid communication networks for future exploratory missions to remote planets. A typical network could include stationary radio transceivers on a remote planet, mobile radio transceivers carried by humans and robots on the planet, terrestrial units connected via the Internet to an interplanetary communication system, and radio relay transceivers aboard spacecraft in orbit about the planet. Prior studies have included tests on prototypes of these networks deployed in Arctic and desert regions chosen to approximate environmental conditions on Mars. Starting from the findings of the prior studies, the paper discusses methods of analysis, design, and testing of the hybrid communication networks. It identifies key radio-frequency (RF) and network engineering issues. Notable among these issues is the study of wireless LAN throughput loss due to repeater use, RF signal strength, and network latency variations. Another major issue is that of using RF-link analysis to ensure adequate link margin in the face of statistical variations in signal strengths.

  9. Radio/FADS/IMU integrated navigation for Mars entry

    NASA Astrophysics Data System (ADS)

    Jiang, Xiuqiang; Li, Shuang; Huang, Xiangyu

    2018-03-01

    Supposing future orbiting and landing collaborative exploration mission as the potential project background, this paper addresses the issue of Mars entry integrated navigation using radio beacon, flush air data sensing system (FADS), and inertial measurement unit (IMU). The range and Doppler information sensed from an orbiting radio beacon, the dynamic pressure and heating data sensed from flush air data sensing system, and acceleration and attitude angular rate outputs from an inertial measurement unit are integrated in an unscented Kalman filter to perform state estimation and suppress the system and measurement noise. Computer simulations show that the proposed integrated navigation scheme can enhance the navigation accuracy, which enables precise entry guidance for the given Mars orbiting and landing collaborative exploration mission.

  10. An MF/HF radio array for radio and radar imaging of the ionosphere

    NASA Astrophysics Data System (ADS)

    Isham, Brett; Gustavsson, Bjorn; Belyey, Vasyl; Bullett, Terrence

    2016-07-01

    The Aguadilla Radio Array will be installed at the Interamerican University Aguadilla Campus, located in northwestern Puerto Rico. The array is intended for broad-band medium and high-frequency (MF/HF, roughly 2 to 25 MHz) radio and bistatic radar observations of the ionosphere. The main array consists of 20 antenna elements, arranged in a semi-random pattern providing a good distribution of baseline vectors, with 6-meter minimum spacing to eliminate spacial aliasing. A relocatable 6-element array is also being developed, in which each element consists of a crossed pair of active electric dipoles and all associated electronics for phase-coherent radio measurements. A primary scientific goal of the array is to create images of the region of ionospheric radio emissions stimulated by the new Arecibo Observatory high-power high-frequency radio transmitter. A second primary goal is the study of ionospheric structure and dynamics via coherent radar imaging of the ionosphere in collaboration with the University of Colorado / NOAA Versatile Interferometric Pulsed Ionospheric Radar (VIPIR), located at the USGS San Juan Observatory in Cayey, Puerto Rico. In addition to ionospheric research in collaboration with the Cayey and Arecibo Observatories, the goals of the project include the development of radio sounding, polarization, interferometry, and imaging techniques, and training of students at the university and high school levels.

  11. A Robust and Energy-Efficient Transport Protocol for Cognitive Radio Sensor Networks

    PubMed Central

    Salim, Shelly; Moh, Sangman

    2014-01-01

    A cognitive radio sensor network (CRSN) is a wireless sensor network in which sensor nodes are equipped with cognitive radio. CRSNs benefit from cognitive radio capabilities such as dynamic spectrum access and transmission parameters reconfigurability; but cognitive radio also brings additional challenges and leads to higher energy consumption. Motivated to improve the energy efficiency in CRSNs, we propose a robust and energy-efficient transport protocol (RETP). The novelties of RETP are two-fold: (I) it combines distributed channel sensing and channel decision with centralized schedule-based data transmission; and (II) it differentiates the types of data transmission on the basis of data content and adopts different acknowledgment methods for different transmission types. To the best of our knowledge, no transport layer protocols have yet been designed for CRSNs. Simulation results show that the proposed protocol achieves remarkably longer network lifetime and shorter event-detection delay compared to those achieved with a conventional transport protocol, while simultaneously preserving event-detection reliability. PMID:25333288

  12. Wireless Sensor Network Radio Power Management and Simulation Models

    DTIC Science & Technology

    2010-01-01

    The Open Electrical & Electronic Engineering Journal, 2010, 4, 21-31 21 1874-1290/10 2010 Bentham Open Open Access Wireless Sensor Network Radio...Air Force Institute of Technology, Wright-Patterson AFB, OH, USA Abstract: Wireless sensor networks (WSNs) create a new frontier in collecting and...consumption. Keywords: Wireless sensor network , power management, energy-efficiency, medium access control (MAC), simulation pa- rameters. 1

  13. The Telecommunications and Data Acquisition Report

    NASA Technical Reports Server (NTRS)

    Posner, E. C. (Editor)

    1984-01-01

    Developments in space communications, radio navigation, radio science, ground-base radio astronomy, reports on the Deep Space Network (DSN) and its Ground Communications Facility (GCF), and applications of radio interferometry at microwave frequencies are discussed.

  14. [Coauthorship networks and institutional collaboration in Revista de Neurología].

    PubMed

    González-Alcaide, G; Alonso-Arroyo, A; González de Dios, J; Sempere, A P; Valderrama-Zurián, J C; Aleixandre-Benavent, R

    Scientific cooperation is essential for the advance of science. Bibliometrics and social network analysis offer evaluation indicators to analyse collaboration in scientific papers. The aim of this study is to characterize scientific collaboration patterns in Revista de Neurología between 2002 and 2006. Coauthorships and institutional relationships of papers published in Revista de Neurología have been identified. Collaboration Index, the most productive authors' and institutional collaboration patterns and the types of institutional collaborations have been quantified. Also, it has been constructed the coauthorship networks and the institutional collaboration network. Networks have been identified and represented using Access and Pajek software tools. The Collaboration Index was 4.01. 56.54% of papers involved institutional collaboration. The collaboration between institutions of the same country prevails (52.7%), followed by collaborations between departments, services or units of the same institution (40.47%) and international collaboration (6.83%). 45 coauthorship networks involving 149 investigators with a high intensity of collaboration and a large institutional network involved 80 centres were observed. Revista de Neurología covers scientific production of a high number of research groups. It has been observed a positive evolution in the collaboration patterns over the time. Nevertheless, it is essential to encourage inter-regional and international collaboration.

  15. Pervasive Radio Mapping of Industrial Environments Using a Virtual Reality Approach

    PubMed Central

    Nedelcu, Adrian-Valentin; Machedon-Pisu, Mihai; Talaba, Doru

    2015-01-01

    Wireless communications in industrial environments are seriously affected by reliability and performance issues, due to the multipath nature of obstacles within such environments. Special attention needs to be given to planning a wireless industrial network, so as to find the optimum spatial position for each of the nodes within the network, and especially for key nodes such as gateways or cluster heads. The aim of this paper is to present a pervasive radio mapping system which captures (senses) data regarding the radio spectrum, using low-cost wireless sensor nodes. This data is the input of radio mapping algorithms that generate electromagnetic propagation profiles. Such profiles are used for identifying obstacles within the environment and optimum propagation pathways. With the purpose of further optimizing the radio planning process, the authors propose a novel human-network interaction (HNI) paradigm that uses 3D virtual environments in order to display the radio maps in a natural, easy-to-perceive manner. The results of this approach illustrate its added value to the field of radio resource planning of industrial communication systems. PMID:26167533

  16. Pervasive Radio Mapping of Industrial Environments Using a Virtual Reality Approach.

    PubMed

    Nedelcu, Adrian-Valentin; Machedon-Pisu, Mihai; Duguleana, Mihai; Talaba, Doru

    2015-01-01

    Wireless communications in industrial environments are seriously affected by reliability and performance issues, due to the multipath nature of obstacles within such environments. Special attention needs to be given to planning a wireless industrial network, so as to find the optimum spatial position for each of the nodes within the network, and especially for key nodes such as gateways or cluster heads. The aim of this paper is to present a pervasive radio mapping system which captures (senses) data regarding the radio spectrum, using low-cost wireless sensor nodes. This data is the input of radio mapping algorithms that generate electromagnetic propagation profiles. Such profiles are used for identifying obstacles within the environment and optimum propagation pathways. With the purpose of further optimizing the radio planning process, the authors propose a novel human-network interaction (HNI) paradigm that uses 3D virtual environments in order to display the radio maps in a natural, easy-to-perceive manner. The results of this approach illustrate its added value to the field of radio resource planning of industrial communication systems.

  17. Sensor Research Targets Smart Building Technology Using Radio-Frequency

    Science.gov Websites

    a battery-free radio-frequency identification (RFID) sensor network with spatiotemporal pattern network based data fusion system for human presence sensing, with ARPA-E awarding the team $2 million over

  18. Network Collaboration with UNIX.

    ERIC Educational Resources Information Center

    Horn, Wm. Dennis

    1993-01-01

    Discusses networking as a collaboration tool in the teaching of technical writing. Argues that some degree of collaboration is innate to all writing, that word processing already facilitates that collaboration, and that networking is the next enhancement to the collaborative process. (RS)

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

    PubMed

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

    2015-04-01

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

  20. Diversity of multilayer networks and its impact on collaborating epidemics

    NASA Astrophysics Data System (ADS)

    Min, Yong; Hu, Jiaren; Wang, Weihong; Ge, Ying; Chang, Jie; Jin, Xiaogang

    2014-12-01

    Interacting epidemics on diverse multilayer networks are increasingly important in modeling and analyzing the diffusion processes of real complex systems. A viral agent spreading on one layer of a multilayer network can interact with its counterparts by promoting (cooperative interaction), suppressing (competitive interaction), or inducing (collaborating interaction) its diffusion on other layers. Collaborating interaction displays different patterns: (i) random collaboration, where intralayer or interlayer induction has the same probability; (ii) concentrating collaboration, where consecutive intralayer induction is guaranteed with a probability of 1; and (iii) cascading collaboration, where consecutive intralayer induction is banned with a probability of 0. In this paper, we develop a top-bottom framework that uses only two distributions, the overlaid degree distribution and edge-type distribution, to model collaborating epidemics on multilayer networks. We then state the response of three collaborating patterns to structural diversity (evenness and difference of network layers). For viral agents with small transmissibility, we find that random collaboration is more effective in networks with higher diversity (high evenness and difference), while the concentrating pattern is more suitable in uneven networks. Interestingly, the cascading pattern requires a network with moderate difference and high evenness, and the moderately uneven coupling of multiple network layers can effectively increase robustness to resist cascading failure. With large transmissibility, however, we find that all collaborating patterns are more effective in high-diversity networks. Our work provides a systemic analysis of collaborating epidemics on multilayer networks. The results enhance our understanding of biotic and informative diffusion through multiple vectors.

  1. The Deep Space Network

    NASA Technical Reports Server (NTRS)

    1988-01-01

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

  2. From Sensor Networks to Internet of Things. Bluetooth Low Energy, a Standard for This Evolution

    PubMed Central

    Hortelano, Diego; Olivares, Teresa; Ruiz, M. Carmen; Garrido-Hidalgo, Celia; López, Vicente

    2017-01-01

    Current sensor networks need to be improved and updated to satisfy new essential requirements of the Internet of Things, where cutting-edge applications will appear. These requirements are: total coverage, zero fails (high performance), scalability and sustainability (hardware and software). We are going to evaluate Bluetooth Low Energy as wireless transmission technology and as the ideal candidate for these improvements, due to its low power consumption, its low cost radio chips and its ability to communicate with users directly, using their smartphones or smartbands. However, this technology is relatively recent, and standard network topologies are not able to fulfil its new requirements. To address these shortcomings, the implementation of other more flexible topologies (as the mesh topology) will be very interesting. After studying it in depth, we have identified certain weaknesses, for example, specific devices are needed to provide network scalability, and the need to choose between high performance or sustainability. In this paper, after presenting the studies carried out on these new technologies, we propose a new packet format and a new BLE mesh topology, with two different configurations: Individual Mesh and Collaborative Mesh. Our results show how this topology improves the scalability, sustainability, coverage and performance. PMID:28216560

  3. From Sensor Networks to Internet of Things. Bluetooth Low Energy, a Standard for This Evolution.

    PubMed

    Hortelano, Diego; Olivares, Teresa; Ruiz, M Carmen; Garrido-Hidalgo, Celia; López, Vicente

    2017-02-14

    Current sensor networks need to be improved and updated to satisfy new essential requirements of the Internet of Things, where cutting-edge applications will appear. These requirements are: total coverage, zero fails (high performance), scalability and sustainability (hardware and software). We are going to evaluate Bluetooth Low Energy as wireless transmission technology and as the ideal candidate for these improvements, due to its low power consumption, its low cost radio chips and its ability to communicate with users directly, using their smartphones or smartbands. However, this technology is relatively recent, and standard network topologies are not able to fulfil its new requirements. To address these shortcomings, the implementation of other more flexible topologies (as the mesh topology) will be very interesting. After studying it in depth, we have identified certain weaknesses, for example, specific devices are needed to provide network scalability, and the need to choose between high performance or sustainability. In this paper, after presenting the studies carried out on these new technologies, we propose a new packet format and a new BLE mesh topology, with two different configurations: Individual Mesh and Collaborative Mesh . Our results show how this topology improves the scalability, sustainability, coverage and performance.

  4. Cognitive Radio for Tactical Wireless Communication Networks

    DTIC Science & Technology

    2011-10-09

    Pursley. Demodulator Statistics for Enhanced Soft-Decision Decoding in CDMA Packet Radio Systems, ICC 2010 - 2010 IEEE International Conference on...likelihood ratio (LLR) metrics and distance metrics. In [BPR08], [BoP09], and [BPR11], we investigated direct-sequence spread-spectrum ( DS -SS...modulation formats, which are among the most robust formats for tactical cognitive radio networks. DS -SS modulation with adaptive soft-decision decoding is

  5. The Telecommunications and Data Acquisition Report. [Deep Space Network

    NASA Technical Reports Server (NTRS)

    Posner, E. C. (Editor)

    1988-01-01

    In space communications, radio navigation, radio science, and ground based radio and radar astronomy, activities of the Deep Space Network and its associated Ground Communications Facility in planning, in supporting research and technology, in implementation, and in operations are reported. Also included is TDA funded activity at JPL on data and information systems and reimbursable DSN work performed for other space agencies through NASA.

  6. A Review on Radio-Over-Fiber Technology-Based Integrated (Optical/Wireless) Networks

    NASA Astrophysics Data System (ADS)

    Rajpal, Shivika; Goyal, Rakesh

    2017-06-01

    In the present paper, radio-over-fiber (RoF) technology has been proposed, which is the integration of the optical and radio networks. With a high transmission capacity, comparatively low cost and low attenuation, optical fiber provides an ideal solution for accomplishing the interconnections. In addition, a radio system enables the significant mobility, flexibility and easy access. Therefore, the system integration can meet the increasing demands of subscribers for voice, data and multimedia services that require the access network to support high data rates at any time and any place inexpensively. RoF has the potentiality to the backbone of the wireless access network and it has gained significant momentum in the last decade as a potential last-mile access scheme. This paper gives the comprehensive review of RoF technology used in the communication system. Concept, applications, advantages and limitations of RoF technology are also discussed in this paper.

  7. The Deep Space Network as an instrument for radio science research

    NASA Technical Reports Server (NTRS)

    Asmar, S. W.; Renzetti, N. A.

    1993-01-01

    Radio science experiments use radio links between spacecraft and sensor instrumentation that is implemented in the Deep Space Network. The deep space communication complexes along with the telecommunications subsystem on board the spacecraft constitute the major elements of the radio science instrumentation. Investigators examine small changes in the phase and/or amplitude of the radio signal propagating from a spacecraft to study the atmospheric and ionospheric structure of planets and satellites, planetary gravitational fields, shapes, masses, planetary rings, ephemerides of planets, solar corona, magnetic fields, cometary comae, and such aspects of the theory of general relativity as gravitational waves and gravitational redshift.

  8. Space Communication and Navigation Testbed Communications Technology for Exploration

    NASA Technical Reports Server (NTRS)

    Reinhart, Richard

    2013-01-01

    NASA developed and launched an experimental flight payload (referred to as the Space Communication and Navigation Test Bed) to investigate software defined radio, networking, and navigation technologies, operationally in the space environment. The payload consists of three software defined radios each compliant to NASAs Space Telecommunications Radio System Architecture, a common software interface description standard for software defined radios. The software defined radios are new technology developed by NASA and industry partners. The payload is externally mounted to the International Space Station truss and available to NASA, industry, and university partners to conduct experiments representative of future mission capability. Experiment operations include in-flight reconfiguration of the SDR waveform functions and payload networking software. The flight system communicates with NASAs orbiting satellite relay network, the Tracking, Data Relay Satellite System at both S-band and Ka-band and to any Earth-based compatible S-band ground station.

  9. EVA Radio DRATS 2011 Report

    NASA Technical Reports Server (NTRS)

    Swank, Aaron J.; Bakula, Casey J.

    2012-01-01

    In the Fall of 2011, National Aeronautics and Space Administration (NASA) Glenn Research Center (GRC) participated in the Desert Research and Technology Studies (DRATS) field experiments held near Flagstaff, Arizona. The objective of the DRATS outing is to provide analog mission testing of candidate technologies for space exploration, especially those technologies applicable to human exploration of extra- terrestrial rocky bodies. These activities are performed at locations with similarities to extra-terrestrial conditions. This report describes the Extravehicular Activity (EVA) Dual-Band Radio Communication System which was demonstrated during the 2011 outing. The EVA radio system is designed to transport both voice and telemetry data through a mobile ad hoc wireless network and employs a dual-band radio configuration. Some key characteristics of this system include: 1. Dual-band radio configuration. 2. Intelligent switching between two different capability wireless networks. 3. Self-healing network. 4. Simultaneous data and voice communication.

  10. Cognitive radio based optimal channel sensing and resources allocation

    NASA Astrophysics Data System (ADS)

    Vijayasarveswari, V.; Khatun, S.; Fakir, M. M.; Nayeem, M. N.; Kamarudin, L. M.; Jakaria, A.

    2017-03-01

    Cognitive radio (CR) is the latest type of wireless technoloy that is proposed to mitigate spectrum saturation problem. İn cognitve radio, secondary user will use primary user's spectrum during primary user's absence without interupting primary user's transmission. This paper focuses on practical cognitive radio network development process using Android based smart phone for the data transmission. Energy detector based sensing method was proposed and used here because it doesnot require primary user's information. Bluetooth and Wi-fi are the two available types of spectrum that was sensed for CR detection. Simulation showed cognitive radio network can be developed using Android based smart phones. So, a complete application was developed using Java based Android Eclipse program. Finally, the application was uploaded and run on Android based smart phone to form and verify CR network for channel sensing and resource allocation. The observed efficiency of the application was around 81%.

  11. Networks of Collaboration among Scientists in a Center for Diabetes Translation Research

    PubMed Central

    Harris, Jenine K.; Wong, Roger; Thompson, Kellie; Haire-Joshu, Debra; Hipp, J. Aaron

    2015-01-01

    Background Transdisciplinary collaboration is essential in addressing the translation gap between scientific discovery and delivery of evidence-based interventions to prevent and treat diabetes. We examined patterns of collaboration among scientists at the Washington University Center for Diabetes Translation Research. Methods Members (n = 56) of the Washington University Center for Diabetes Translation Research were surveyed about collaboration overall and on publications, presentations, and grants; 87.5% responded (n = 49). We used traditional and network descriptive statistics and visualization to examine the networks and exponential random graph modeling to identify predictors of collaboration. Results The 56 network members represented nine disciplines. On average, network members had been affiliated with the center for 3.86 years (s.d. = 1.41). The director was by far the most central in all networks. The overall and publication networks were the densest, while the overall and grant networks were the most centralized. The grant network was the most transdisciplinary. The presentation network was the least dense, least centralized, and least transdisciplinary. For every year of center affiliation, network members were 10% more likely to collaborate (OR: 1.10; 95% CI: 1.00–1.21) and 13% more likely to write a paper together (OR: 1.13; 95% CI: 1.02–1.25). Network members in the same discipline were over twice as likely to collaborate in the overall network (OR: 2.10; 95% CI: 1.40–3.15); however, discipline was not associated with collaboration in the other networks. Rank was not associated with collaboration in any network. Conclusions As transdisciplinary centers become more common, it is important to identify structural features, such as a central leader and ongoing collaboration over time, associated with scholarly productivity and, ultimately, with advancing science and practice. PMID:26301873

  12. Networks of Collaboration among Scientists in a Center for Diabetes Translation Research.

    PubMed

    Harris, Jenine K; Wong, Roger; Thompson, Kellie; Haire-Joshu, Debra; Hipp, J Aaron

    2015-01-01

    Transdisciplinary collaboration is essential in addressing the translation gap between scientific discovery and delivery of evidence-based interventions to prevent and treat diabetes. We examined patterns of collaboration among scientists at the Washington University Center for Diabetes Translation Research. Members (n = 56) of the Washington University Center for Diabetes Translation Research were surveyed about collaboration overall and on publications, presentations, and grants; 87.5% responded (n = 49). We used traditional and network descriptive statistics and visualization to examine the networks and exponential random graph modeling to identify predictors of collaboration. The 56 network members represented nine disciplines. On average, network members had been affiliated with the center for 3.86 years (s.d. = 1.41). The director was by far the most central in all networks. The overall and publication networks were the densest, while the overall and grant networks were the most centralized. The grant network was the most transdisciplinary. The presentation network was the least dense, least centralized, and least transdisciplinary. For every year of center affiliation, network members were 10% more likely to collaborate (OR: 1.10; 95% CI: 1.00-1.21) and 13% more likely to write a paper together (OR: 1.13; 95% CI: 1.02-1.25). Network members in the same discipline were over twice as likely to collaborate in the overall network (OR: 2.10; 95% CI: 1.40-3.15); however, discipline was not associated with collaboration in the other networks. Rank was not associated with collaboration in any network. As transdisciplinary centers become more common, it is important to identify structural features, such as a central leader and ongoing collaboration over time, associated with scholarly productivity and, ultimately, with advancing science and practice.

  13. Performance evaluation of cognitive radio in advanced metering infrastructure communication

    NASA Astrophysics Data System (ADS)

    Hiew, Yik-Kuan; Mohd Aripin, Norazizah; Din, Norashidah Md

    2016-03-01

    Smart grid is an intelligent electricity grid system. A reliable two-way communication system is required to transmit both critical and non-critical smart grid data. However, it is difficult to locate a huge chunk of dedicated spectrum for smart grid communications. Hence, cognitive radio based communication is applied. Cognitive radio allows smart grid users to access licensed spectrums opportunistically with the constraint of not causing harmful interference to licensed users. In this paper, a cognitive radio based smart grid communication framework is proposed. Smart grid framework consists of Home Area Network (HAN) and Advanced Metering Infrastructure (AMI), while AMI is made up of Neighborhood Area Network (NAN) and Wide Area Network (WAN). In this paper, the authors only report the findings for AMI communication. AMI is smart grid domain that comprises smart meters, data aggregator unit, and billing center. Meter data are collected by smart meters and transmitted to data aggregator unit by using cognitive 802.11 technique; data aggregator unit then relays the data to billing center using cognitive WiMAX and TV white space. The performance of cognitive radio in AMI communication is investigated using Network Simulator 2. Simulation results show that cognitive radio improves the latency and throughput performances of AMI. Besides, cognitive radio also improves spectrum utilization efficiency of WiMAX band from 5.92% to 9.24% and duty cycle of TV band from 6.6% to 10.77%.

  14. Plate Boundary Observatory GPS Network Status in California

    NASA Astrophysics Data System (ADS)

    Walls, C. P.; Austin, K. E.; Dittman, T.; Mann, D.; Basset, A.; Turner, R.; Lawrence, S.; Woolace, A. C.; Kasmer, D.; Hodgkinson, K. M.; Feaux, K.; Mattioli, G. S.

    2015-12-01

    The EarthScope PBO GPS network, funded by the NSF and operated by UNAVCO, is comprised of 599 permanent GPS stations spanning three principal tectonic regimes and is administered by separate management regions (Subduction - Pacific Northwest [91 sites], Extension - East [41 sites], Transform - Southwest [467 sites]). Since the close of construction in September 2008 various enhancements have been implemented through additional funding by the NSF, NOAA, and NASA and in collaboration with stakeholders such as Caltrans, Scripps, and the USGS. Initially, the majority of stations used first generation IP based cellular modems and radios capable of ~10KB/s data rates. The bandwidth limitation was a challenge for regional high-rate data downloads for GPS-seismology and airborne LiDAR surveys, and real-time data flow. Today, only 13 of the original cell modems remain with 297 upgraded cell modems providing 3G/4G/LTE data communications with transfer rates ranging from 80-400 KB/s. Ongoing radio network expansion and upgrades continue to harden communications. 32 VSAT and one manual download site remain. In CA, the network capabilities for 1Hz and 5Hz downloads or real-time streaming are ~95%, ~80% and ~65%, respectively. During the past year, uptime ranged from 94-99% with data return for 15 s data exceeding 99%. Real-time (1 Hz) data from 204 sites are distributed in BINEX and RTCM 2.3/3.1 formats with an average latency of 0.5 s and completion of 86%. A variety of geophysical sensors are co-located with the GPS stations and include: 21 MEMS accelerometers, 31 strong motion and broadband seismometers, 9 borehole strainmeters and 1 long baseline strainmeter. Vaisala meteorological instruments are located at 60 sites of which 38 stream GPS/Met data. In an effort to modernize the network, Trimble NetRS receivers are gradually being replaced with GNSS-capable/enabled receivers and antennas. Today, 11 stations are GLONASS enabled and 84 are GNSS capable.

  15. Facilitative Components of Collaborative Learning: A Review of Nine Health Research Networks.

    PubMed

    Leroy, Lisa; Rittner, Jessica Levin; Johnson, Karin E; Gerteis, Jessie; Miller, Therese

    2017-02-01

    Collaborative research networks are increasingly used as an effective mechanism for accelerating knowledge transfer into policy and practice. This paper explored the characteristics and collaborative learning approaches of nine health research networks. Semi-structured interviews with representatives from eight diverse US health services research networks conducted between November 2012 and January 2013 and program evaluation data from a ninth. The qualitative analysis assessed each network's purpose, duration, funding sources, governance structure, methods used to foster collaboration, and barriers and facilitators to collaborative learning. The authors reviewed detailed notes from the interviews to distill salient themes. Face-to-face meetings, intentional facilitation and communication, shared vision, trust among members and willingness to work together were key facilitators of collaborative learning. Competing priorities for members, limited funding and lack of long-term support and geographic dispersion were the main barriers to coordination and collaboration across research network members. The findings illustrate the importance of collaborative learning in research networks and the challenges to evaluating the success of research network functionality. Conducting readiness assessments and developing process and outcome evaluation metrics will advance the design and show the impact of collaborative research networks. Copyright © 2017 Longwoods Publishing.

  16. The Development of the Command and Control Centre for Trial Kondari

    DTIC Science & Technology

    2010-07-01

    the C2 centre inside a blue bubble whose modems have privately assigned IP addresses which are authenticated by Telstra’s radius server. No other sim...cards can communicate on this private network unless authorised by the radius server. The Next IP network is a network bubble within the larger Next...for all machines on the network.  EPLRS Network Manager (ENM) radio – authenticates and manages all the EPLRS radios. The basic plan’s final

  17. [Microstrip antenna design and system research of radio frequency identification temperature sensor].

    PubMed

    Yang, Hao; Yang, Xiaohe; Chen, Yuquan; Pan, Min

    2008-12-01

    Radio frequency identification sensor network, which is a product of integrating radio frequency identification (RFID) with wireless sensor network (WSN), is introduced in this paper. The principle of radio frequency identification sensor is analyzed, and the importance of the antenna is emphasized. Then three kinds of common antennae, namely coil antenna, dipole antenna and microstrip antenna, are discussed. Subsequently, according to requirement, we have designed a microstrip antenna in a wireless temperature-monitoring and controlling system. The measurement of factual effect showed the requirement was fulfilled.

  18. Exploiting the Use of Social Networking to Facilitate Collaboration in the Scientific Community

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Coppock, Edrick G.

    The goal of this project was to exploit social networking to facilitate scientific collaboration. The project objective was to research and identify scientific collaboration styles that are best served by social networking applications and to model the most effective social networking applications to substantiate how social networking can support scientific collaboration. To achieve this goal and objective, the project was to develop an understanding of the types of collaborations conducted by scientific researchers, through classification, data analysis and identification of unique collaboration requirements. Another technical objective in support of this goal was to understand the current state of technology inmore » collaboration tools. In order to test hypotheses about which social networking applications effectively support scientific collaboration the project was to create a prototype scientific collaboration system. The ultimate goal for testing the hypotheses and research of the project was to refine the prototype into a functional application that could effectively facilitate and grow collaboration within the U.S. Department of Energy (DOE) research community.« less

  19. Using Social Network Analysis to Assess Mentorship and Collaboration in a Public Health Network.

    PubMed

    Petrescu-Prahova, Miruna; Belza, Basia; Leith, Katherine; Allen, Peg; Coe, Norma B; Anderson, Lynda A

    2015-08-20

    Addressing chronic disease burden requires the creation of collaborative networks to promote systemic changes and engage stakeholders. Although many such networks exist, they are rarely assessed with tools that account for their complexity. This study examined the structure of mentorship and collaboration relationships among members of the Healthy Aging Research Network (HAN) using social network analysis (SNA). We invited 97 HAN members and partners to complete an online social network survey that included closed-ended questions about HAN-specific mentorship and collaboration during the previous 12 months. Collaboration was measured by examining the activity of the network on 6 types of products: published articles, in-progress manuscripts, grant applications, tools, research projects, and presentations. We computed network-level measures such as density, number of components, and centralization to assess the cohesiveness of the network. Sixty-three respondents completed the survey (response rate, 65%). Responses, which included information about collaboration with nonrespondents, suggested that 74% of HAN members were connected through mentorship ties and that all 97 members were connected through at least one form of collaboration. Mentorship and collaboration ties were present both within and across boundaries of HAN member organizations. SNA of public health collaborative networks provides understanding about the structure of relationships that are formed as a result of participation in network activities. This approach may offer members and funders a way to assess the impact of such networks that goes beyond simply measuring products and participation at the individual level.

  20. The Telecommunications and Data Acquisition Report. [Deep Space Network

    NASA Technical Reports Server (NTRS)

    Posner, E. C. (Editor)

    1986-01-01

    This publication, one of a series formerly titled The Deep Space Network Progress Report, documents DSN progress in flight project support, tracking and data acquisition research and technology, network engineering, hardware and software implementation, and operations. In addition, developments in Earth-based radio technology as applied to geodynamics, astrophysics and the radio search for extraterrestrial intelligence are reported.

  1. Improved Wireless Security through Physical Layer Protocol Manipulation and Radio Frequency Fingerprinting

    DTIC Science & Technology

    2014-09-18

    radios in a cognitive radio network using a radio frequency fingerprinting based method. In IEEE International Conference on Communications (ICC...IMPROVEDWIRELESS SECURITY THROUGH PHYSICAL LAYER PROTOCOL MANIPULATION AND RADIO FREQUENCY FINGERPRINTING DISSERTATION Benjamin W. Ramsey, Captain...PHYSICAL LAYER PROTOCOL MANIPULATION AND RADIO FREQUENCY FINGERPRINTING DISSERTATION Presented to the Faculty Graduate School of Engineering and

  2. Performance Analysis of Relay Subset Selection for Amplify-and-Forward Cognitive Relay Networks

    PubMed Central

    Qureshi, Ijaz Mansoor; Malik, Aqdas Naveed; Zubair, Muhammad

    2014-01-01

    Cooperative communication is regarded as a key technology in wireless networks, including cognitive radio networks (CRNs), which increases the diversity order of the signal to combat the unfavorable effects of the fading channels, by allowing distributed terminals to collaborate through sophisticated signal processing. Underlay CRNs have strict interference constraints towards the secondary users (SUs) active in the frequency band of the primary users (PUs), which limits their transmit power and their coverage area. Relay selection offers a potential solution to the challenges faced by underlay networks, by selecting either single best relay or a subset of potential relay set under different design requirements and assumptions. The best relay selection schemes proposed in the literature for amplify-and-forward (AF) based underlay cognitive relay networks have been very well studied in terms of outage probability (OP) and bit error rate (BER), which is deficient in multiple relay selection schemes. The novelty of this work is to study the outage behavior of multiple relay selection in the underlay CRN and derive the closed-form expressions for the OP and BER through cumulative distribution function (CDF) of the SNR received at the destination. The effectiveness of relay subset selection is shown through simulation results. PMID:24737980

  3. Social Network Analysis of Biomedical Research Collaboration Networks in a CTSA Institution

    PubMed Central

    Bian, Jiang; Xie, Mengjun; Topaloglu, Umit; Hudson, Teresa; Eswaran, Hari; Hogan, William

    2014-01-01

    BACKGROUND The popularity of social networks has triggered a number of research efforts on network analyses of research collaborations in the Clinical and Translational Science Award (CTSA) community. Those studies mainly focus on the general understanding of collaboration networks by measuring common network metrics. More fundamental questions about collaborations still remain unanswered such as recognizing “influential” nodes and identifying potential new collaborations that are most rewarding. METHODS We analyzed biomedical research collaboration networks (RCNs) constructed from a dataset of research grants collected at a CTSA institution (i.e. University of Arkansas for Medical Sciences (UAMS)) in a comprehensive and systematic manner. First, our analysis covers the full spectrum of a RCN study: from network modeling to network characteristics measurement, from key nodes recognition to potential links (collaborations) suggestion. Second, our analysis employs non-conventional model and techniques including a weighted network model for representing collaboration strength, rank aggregation for detecting important nodes, and Random Walk with Restart (RWR) for suggesting new research collaborations. RESULTS By applying our models and techniques to RCNs at UAMS prior to and after the CTSA, we have gained valuable insights that not only reveal the temporal evolution of the network dynamics but also assess the effectiveness of the CTSA and its impact on a research institution. We find that collaboration networks at UAMS are not scale-free but small-world. Quantitative measures have been obtained to evident that the RCNs at UAMS are moving towards favoring multidisciplinary research. Moreover, our link prediction model creates the basis of collaboration recommendations with an impressive accuracy (AUC: 0.990, MAP@3: 1.48 and MAP@5: 1.522). Last but not least, an open-source visual analytical tool for RCNs is being developed and released through Github. CONCLUSIONS Through this study, we have developed a set of techniques and tools for analyzing research collaboration networks and conducted a comprehensive case study focusing on a CTSA institution. Our findings demonstrate the promising future of these techniques and tools in understanding the generative mechanisms of research collaborations and helping identify beneficial collaborations to members in the research community. PMID:24560679

  4. Evolution of the research collaboration network in a productive department.

    PubMed

    Katerndahl, David

    2012-02-01

    Understanding collaboration networks can facilitate the research growth of new or developing departments. The purpose of this study was to use social network analysis to understand how the research collaboration network evolved within a productive department. Over a 13-year period, a departmental faculty completed an annual survey describing their research collaborations. Data were analyzed using social network analysis. Network measures focused on connectedness, distance, groupings and heterogeneity of distribution, while measures for the research director and external collaboration focused on centrality and roles within the network. Longitudinal patterns of network collaboration were assessed using Simulation Investigation for Empirical Network Analysis software (University of Groningen, Groningen, Netherlands). Based upon the number of active research projects, research development can be divided into three phases. The initial development phase was characterized by increasing centralization and collaboration focused within a single subject area. During the maintenance phase, measures went through cycles, possibly because of changes in faculty composition. While the research director was not a 'key player' within the network during the first several years, external collaboration played a central role during all phases. Longitudinal analysis found that forming ties was more likely when the opportunity for network closure existed and when those around you are principal investigators (PIs). Initial development of research relied heavily upon a centralized network involving external collaboration; a central position of the research director during research development was not important. Changes in collaboration depended upon faculty gender and tenure track as well as transitivity and the 'popularity of PIs'. © 2011 Blackwell Publishing Ltd.

  5. Passive Thermal Design Approach for the Space Communications and Navigation (SCaN) Testbed Experiment on the International Space Station (ISS)

    NASA Technical Reports Server (NTRS)

    Siamidis, John; Yuko, Jim

    2014-01-01

    The Space Communications and Navigation (SCaN) Program Office at NASA Headquarters oversees all of NASAs space communications activities. SCaN manages and directs the ground-based facilities and services provided by the Deep Space Network (DSN), Near Earth Network (NEN), and the Space Network (SN). Through the SCaN Program Office, NASA GRC developed a Software Defined Radio (SDR) testbed experiment (SCaN testbed experiment) for use on the International Space Station (ISS). It is comprised of three different SDR radios, the Jet Propulsion Laboratory (JPL) radio, Harris Corporation radio, and the General Dynamics Corporation radio. The SCaN testbed experiment provides an on-orbit, adaptable, SDR Space Telecommunications Radio System (STRS) - based facility to conduct a suite of experiments to advance the Software Defined Radio, Space Telecommunications Radio Systems (STRS) standards, reduce risk (Technology Readiness Level (TRL) advancement) for candidate Constellation future space flight hardware software, and demonstrate space communication links critical to future NASA exploration missions. The SCaN testbed project provides NASA, industry, other Government agencies, and academic partners the opportunity to develop and field communications, navigation, and networking technologies in the laboratory and space environment based on reconfigurable, software defined radio platforms and the STRS Architecture.The SCaN testbed is resident on the P3 Express Logistics Carrier (ELC) on the exterior truss of the International Space Station (ISS). The SCaN testbed payload launched on the Japanese Aerospace Exploration Agency (JAXA) H-II Transfer Vehicle (HTV) and was installed on the ISS P3 ELC located on the inboard RAM P3 site. The daily operations and testing are managed out of NASA GRC in the Telescience Support Center (TSC).

  6. The Quiet Skies Project

    ERIC Educational Resources Information Center

    Rapp, Steve

    2008-01-01

    To help promote student awareness of the connection between radio astronomy and radio frequency interference (RFI), an inquiry-based science curriculum was developed to allow high school students to determine RFI levels in their communities. The Quiet Skies Project--the result of a collaboration between the National Aeronautics and Space…

  7. Performance Analysis on the Coexistence of Multiple Cognitive Radio Networks

    DTIC Science & Technology

    2015-05-28

    the scarce spectrum resources. Cognitive radio is a key in minimizing the spectral congestion through its adaptability, where the radio parameters...static allocation of spectrum results in congestion in some parts of the spectrum and non use in some others, therefore, spectra utilization is...well as the secondary user (SU) activities in multiple CR networks. It is shown that the scheduler provided much needed gain during congestions . However

  8. Sensor Authentication in Collaborating Sensor Networks

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Bielefeldt, Jake Uriah

    2014-11-01

    In this thesis, we address a new security problem in the realm of collaborating sensor networks. By collaborating sensor networks, we refer to the networks of sensor networks collaborating on a mission, with each sensor network is independently owned and operated by separate entities. Such networks are practical where a number of independent entities can deploy their own sensor networks in multi-national, commercial, and environmental scenarios, and some of these networks will integrate complementary functionalities for a mission. In the scenario, we address an authentication problem wherein the goal is for the Operator O i of Sensor Network S imore » to correctly determine the number of active sensors in Network Si. Such a problem is challenging in collaborating sensor networks where other sensor networks, despite showing an intent to collaborate, may not be completely trustworthy and could compromise the authentication process. We propose two authentication protocols to address this problem. Our protocols rely on Physically Unclonable Functions, which are a hardware based authentication primitive exploiting inherent randomness in circuit fabrication. Our protocols are light-weight, energy efficient, and highly secure against a number of attacks. To the best of our knowledge, ours is the first to addresses a practical security problem in collaborating sensor networks.« less

  9. The Telecommunications and Data Acquisition Report

    NASA Technical Reports Server (NTRS)

    Posner, E. C. (Editor)

    1989-01-01

    Archival reports on developments in programs managed by the Jet Propulsion Laboratory's Office of Telecommunications and Data Acquisition are provided. Space communications, radio navigation, radio science, and ground based radio and radio astronomy are discussed. Deep Space Network projects are also discussed.

  10. Supporting Effective Collaboration: Using a Rearview Mirror to Look Forward

    ERIC Educational Resources Information Center

    McManus, Margaret M.; Aiken, Robert M.

    2016-01-01

    Our original research, to design and develop an Intelligent Collaborative Learning System (ICLS), yielded the creation of a Group Leader Tutor software system which utilizes a Collaborative Skills Network to monitor students working collaboratively in a networked environment. The Collaborative Skills Network was a conceptualization of…

  11. Pliable Cognitive MAC for Heterogeneous Adaptive Cognitive Radio Sensor Networks.

    PubMed

    Al-Medhwahi, Mohammed; Hashim, Fazirulhisyam; Ali, Borhanuddin Mohd; Sali, Aduwati

    2016-01-01

    The rapid expansion of wireless monitoring and surveillance applications in several domains reinforces the trend of exploiting emerging technologies such as the cognitive radio. However, these technologies have to adjust their working concepts to consider the common characteristics of conventional wireless sensor networks (WSNs). The cognitive radio sensor network (CRSN), still an immature technology, has to deal with new networks that might have different types of data, traffic patterns, or quality of service (QoS) requirements. In this paper, we design and model a new cognitive radio-based medium access control (MAC) algorithm dealing with the heterogeneous nature of the developed networks in terms of either the traffic pattern or the required QoS for the node applications. The proposed algorithm decreases the consumed power on several fronts, provides satisfactory levels of latency and spectrum utilization with efficient scheduling, and manages the radio resources for various traffic conditions. An intensive performance evaluation is conducted to study the impact of key parameters such as the channel idle time length, node density, and the number of available channels. The performance evaluation of the proposed algorithm shows a better performance than the comparable protocols. Moreover, the results manifest that the proposed algorithm is suitable for real time monitoring applications.

  12. Pliable Cognitive MAC for Heterogeneous Adaptive Cognitive Radio Sensor Networks

    PubMed Central

    Ali, Borhanuddin Mohd; Sali, Aduwati

    2016-01-01

    The rapid expansion of wireless monitoring and surveillance applications in several domains reinforces the trend of exploiting emerging technologies such as the cognitive radio. However, these technologies have to adjust their working concepts to consider the common characteristics of conventional wireless sensor networks (WSNs). The cognitive radio sensor network (CRSN), still an immature technology, has to deal with new networks that might have different types of data, traffic patterns, or quality of service (QoS) requirements. In this paper, we design and model a new cognitive radio-based medium access control (MAC) algorithm dealing with the heterogeneous nature of the developed networks in terms of either the traffic pattern or the required QoS for the node applications. The proposed algorithm decreases the consumed power on several fronts, provides satisfactory levels of latency and spectrum utilization with efficient scheduling, and manages the radio resources for various traffic conditions. An intensive performance evaluation is conducted to study the impact of key parameters such as the channel idle time length, node density, and the number of available channels. The performance evaluation of the proposed algorithm shows a better performance than the comparable protocols. Moreover, the results manifest that the proposed algorithm is suitable for real time monitoring applications. PMID:27257964

  13. Facilitative Components of Collaborative Learning: A Review of Nine Health Research Networks

    PubMed Central

    Rittner, Jessica Levin; Johnson, Karin E.; Gerteis, Jessie; Miller, Therese

    2017-01-01

    Objective: Collaborative research networks are increasingly used as an effective mechanism for accelerating knowledge transfer into policy and practice. This paper explored the characteristics and collaborative learning approaches of nine health research networks. Data sources/study setting: Semi-structured interviews with representatives from eight diverse US health services research networks conducted between November 2012 and January 2013 and program evaluation data from a ninth. Study design: The qualitative analysis assessed each network's purpose, duration, funding sources, governance structure, methods used to foster collaboration, and barriers and facilitators to collaborative learning. Data collection: The authors reviewed detailed notes from the interviews to distill salient themes. Principal findings: Face-to-face meetings, intentional facilitation and communication, shared vision, trust among members and willingness to work together were key facilitators of collaborative learning. Competing priorities for members, limited funding and lack of long-term support and geographic dispersion were the main barriers to coordination and collaboration across research network members. Conclusion: The findings illustrate the importance of collaborative learning in research networks and the challenges to evaluating the success of research network functionality. Conducting readiness assessments and developing process and outcome evaluation metrics will advance the design and show the impact of collaborative research networks. PMID:28277202

  14. Cognitive Radio Networks for Tactical Wireless Communications

    DTIC Science & Technology

    2014-12-01

    exists. Instead, security is an evolving process, as we have seen in the context of WLANs and 2G / 3G networks. New system vulnerabilities continue to...in the network configuration and radio parameters take place due to mobility of platforms, and variation in other users of the RF environment. CRNs...dynamic spectrum access experimentally, and it represents the largest military Mobile Ad hoc Network (MANET) as of today. The WNaN demonstrator has been

  15. GLOBECOM '85 - Global Telecommunications Conference, New Orleans, LA, December 2-5, 1985, Conference Record. Volumes 1, 2, & 3

    NASA Astrophysics Data System (ADS)

    Various papers on global telecommunications are presented. The general topics addressed include: multiservice integration with optical fibers, multicompany owned telecommunication networks, softworks quality and reliability, advanced on-board processing, impact of new services and systems on operations and maintenance, analytical studies of protocols for data communication networks, topics in packet radio networking, CCITT No. 7 to support new services, document processing and communication, antenna technology and system aspects in satellite communications. Also considered are: communication systems modelling methodology, experimental integrated local area voice/data nets, spread spectrum communications, motion video at the DS-0 rate, optical and data communications, intelligent work stations, switch performance analysis, novel radio communication systems, wireless local networks, ISDN services, LAN communication protocols, user-system interface, radio propagation and performance, mobile satellite system, software for computer networks, VLSI for ISDN terminals, quality management, man-machine interfaces in switching, and local area network performance.

  16. Development of NASA's Space Communications and Navigation Test Bed Aboard ISS to Investigate SDR, On-Board Networking and Navigation Technologies

    NASA Technical Reports Server (NTRS)

    Reinhart, Richard C.; Kacpura, Thomas J.; Johnson, Sandra K.; Lux, James P.

    2010-01-01

    NASA is developing an experimental flight payload (referred to as the Space Communication and Navigation (SCAN) Test Bed) to investigate software defined radio (SDR), networking, and navigation technologies, operationally in the space environment. The payload consists of three software defined radios each compliant to NASA s Space Telecommunications Radio System Architecture, a common software interface description standard for software defined radios. The software defined radios are new technology developments underway by NASA and industry partners. Planned for launch in early 2012, the payload will be externally mounted to the International Space Station truss and conduct experiments representative of future mission capability.

  17. Telecommunications and data acquisition

    NASA Technical Reports Server (NTRS)

    Renzetti, N. A. (Editor)

    1981-01-01

    Deep Space Network progress in flight project support, tracking and data acquisition research and technology, network engineering, hardware and software implementation, and operations is reported. In addition, developments in Earth based radio technology as applied to geodynamics, astrophysics, and the radio search for extraterrestrial intelligence are reported.

  18. A Collaboration Network Model Of Cytokine-Protein Network

    NASA Astrophysics Data System (ADS)

    Zou, Sheng-Rong; Zhou, Ta; Peng, Yu-Jing; Guo, Zhong-Wei; Gu, Chang-Gui; He, Da-Ren

    2008-03-01

    Complex networks provide us a new view for investigation of immune systems. We collect data through STRING database and present a network description with cooperation network model. The cytokine-protein network model we consider is constituted by two kinds of nodes, one is immune cytokine types which can be regarded as collaboration acts, the other one is protein type which can be regarded as collaboration actors. From act degree distribution that can be well described by typical SPL (shifted power law) functions [1], we find that HRAS, TNFRSF13C, S100A8, S100A1, MAPK8, S100A7, LIF, CCL4, CXCL13 are highly collaborated with other proteins. It reveals that these mediators are important in cytokine-protein network to regulate immune activity. Dyad in the collaboration networks can be defined as two proteins and they appear in one cytokine collaboration relationship. The dyad act degree distribution can also be well described by typical SPL functions. [1] Assortativity and act degree distribution of some collaboration networks, Hui Chang, Bei-Bei Su, Yue-Ping Zhou, Daren He, Physica A, 383 (2007) 687-702

  19. Examining the Emergence of Large-Scale Structures in Collaboration Networks: Methods in Sociological Analysis

    ERIC Educational Resources Information Center

    Ghosh, Jaideep; Kshitij, Avinash

    2017-01-01

    This article introduces a number of methods that can be useful for examining the emergence of large-scale structures in collaboration networks. The study contributes to sociological research by investigating how clusters of research collaborators evolve and sometimes percolate in a collaboration network. Typically, we find that in our networks,…

  20. Analysis of multiuser mixed RF/FSO relay networks for performance improvements in Cloud Computing-Based Radio Access Networks (CC-RANs)

    NASA Astrophysics Data System (ADS)

    Alimi, Isiaka A.; Monteiro, Paulo P.; Teixeira, António L.

    2017-11-01

    The key paths toward the fifth generation (5G) network requirements are towards centralized processing and small-cell densification systems that are implemented on the cloud computing-based radio access networks (CC-RANs). The increasing recognitions of the CC-RANs can be attributed to their valuable features regarding system performance optimization and cost-effectiveness. Nevertheless, realization of the stringent requirements of the fronthaul that connects the network elements is highly demanding. In this paper, considering the small-cell network architectures, we present multiuser mixed radio-frequency/free-space optical (RF/FSO) relay networks as feasible technologies for the alleviation of the stringent requirements in the CC-RANs. In this study, we use the end-to-end (e2e) outage probability, average symbol error probability (ASEP), and ergodic channel capacity as the performance metrics in our analysis. Simulation results show the suitability of deployment of mixed RF/FSO schemes in the real-life scenarios.

  1. Multi-channel distributed coordinated function over single radio in wireless sensor networks.

    PubMed

    Campbell, Carlene E-A; Loo, Kok-Keong Jonathan; Gemikonakli, Orhan; Khan, Shafiullah; Singh, Dhananjay

    2011-01-01

    Multi-channel assignments are becoming the solution of choice to improve performance in single radio for wireless networks. Multi-channel allows wireless networks to assign different channels to different nodes in real-time transmission. In this paper, we propose a new approach, Multi-channel Distributed Coordinated Function (MC-DCF) which takes advantage of multi-channel assignment. The backoff algorithm of the IEEE 802.11 distributed coordination function (DCF) was modified to invoke channel switching, based on threshold criteria in order to improve the overall throughput for wireless sensor networks (WSNs) over 802.11 networks. We presented simulation experiments in order to investigate the characteristics of multi-channel communication in wireless sensor networks using an NS2 platform. Nodes only use a single radio and perform channel switching only after specified threshold is reached. Single radio can only work on one channel at any given time. All nodes initiate constant bit rate streams towards the receiving nodes. In this work, we studied the impact of non-overlapping channels in the 2.4 frequency band on: constant bit rate (CBR) streams, node density, source nodes sending data directly to sink and signal strength by varying distances between the sensor nodes and operating frequencies of the radios with different data rates. We showed that multi-channel enhancement using our proposed algorithm provides significant improvement in terms of throughput, packet delivery ratio and delay. This technique can be considered for WSNs future use in 802.11 networks especially when the IEEE 802.11n becomes popular thereby may prevent the 802.15.4 network from operating effectively in the 2.4 GHz frequency band.

  2. Multi-Channel Distributed Coordinated Function over Single Radio in Wireless Sensor Networks

    PubMed Central

    Campbell, Carlene E.-A.; Loo, Kok-Keong (Jonathan); Gemikonakli, Orhan; Khan, Shafiullah; Singh, Dhananjay

    2011-01-01

    Multi-channel assignments are becoming the solution of choice to improve performance in single radio for wireless networks. Multi-channel allows wireless networks to assign different channels to different nodes in real-time transmission. In this paper, we propose a new approach, Multi-channel Distributed Coordinated Function (MC-DCF) which takes advantage of multi-channel assignment. The backoff algorithm of the IEEE 802.11 distributed coordination function (DCF) was modified to invoke channel switching, based on threshold criteria in order to improve the overall throughput for wireless sensor networks (WSNs) over 802.11 networks. We presented simulation experiments in order to investigate the characteristics of multi-channel communication in wireless sensor networks using an NS2 platform. Nodes only use a single radio and perform channel switching only after specified threshold is reached. Single radio can only work on one channel at any given time. All nodes initiate constant bit rate streams towards the receiving nodes. In this work, we studied the impact of non-overlapping channels in the 2.4 frequency band on: constant bit rate (CBR) streams, node density, source nodes sending data directly to sink and signal strength by varying distances between the sensor nodes and operating frequencies of the radios with different data rates. We showed that multi-channel enhancement using our proposed algorithm provides significant improvement in terms of throughput, packet delivery ratio and delay. This technique can be considered for WSNs future use in 802.11 networks especially when the IEEE 802.11n becomes popular thereby may prevent the 802.15.4 network from operating effectively in the 2.4 GHz frequency band. PMID:22346614

  3. CollaborationViz: Interactive Visual Exploration of Biomedical Research Collaboration Networks

    PubMed Central

    Bian, Jiang; Xie, Mengjun; Hudson, Teresa J.; Eswaran, Hari; Brochhausen, Mathias; Hanna, Josh; Hogan, William R.

    2014-01-01

    Social network analysis (SNA) helps us understand patterns of interaction between social entities. A number of SNA studies have shed light on the characteristics of research collaboration networks (RCNs). Especially, in the Clinical Translational Science Award (CTSA) community, SNA provides us a set of effective tools to quantitatively assess research collaborations and the impact of CTSA. However, descriptive network statistics are difficult for non-experts to understand. In this article, we present our experiences of building meaningful network visualizations to facilitate a series of visual analysis tasks. The basis of our design is multidimensional, visual aggregation of network dynamics. The resulting visualizations can help uncover hidden structures in the networks, elicit new observations of the network dynamics, compare different investigators and investigator groups, determine critical factors to the network evolution, and help direct further analyses. We applied our visualization techniques to explore the biomedical RCNs at the University of Arkansas for Medical Sciences – a CTSA institution. And, we created CollaborationViz, an open-source visual analytical tool to help network researchers and administration apprehend the network dynamics of research collaborations through interactive visualization. PMID:25405477

  4. The telecommunications and data acquisition report

    NASA Technical Reports Server (NTRS)

    Renzetti, N. A.

    1980-01-01

    Deep Space Network progress in flight project support, tracking and data acquisition research and technology, network engineering, hardware and software implemention, and operations is documented. In addition, developments in Earth based radio technology as applied to geodynamics, astrophysics, and the radio search for extraterrestrial intelligence are reported.

  5. The Telecommunications and Data Acquisition Report

    NASA Technical Reports Server (NTRS)

    Posner, E. C. (Editor)

    1986-01-01

    Deep Space Network progress in flight project support, tracking and data acquisition research and technology, network engineering, hardware and software implementation, and operations is documented. In addition, developments in Earth-based radio technology as applied to geodynamics, astrophysics and the radio search for extraterrestrial intelligence are reported.

  6. Space Communication and Navigation SDR Testbed, Overview and Opportunity for Experiments

    NASA Technical Reports Server (NTRS)

    Reinhart, Richard C.

    2013-01-01

    NASA has developed an experimental flight payload (referred to as the Space Communication and Navigation (SCAN) Test Bed) to investigate software defined radio (SDR) communications, networking, and navigation technologies, operationally in the space environment. The payload consists of three software defined radios each compliant to NASAs Space Telecommunications Radio System Architecture, a common software interface description standard for software defined radios. The software defined radios are new technology developments underway by NASA and industry partners launched in 2012. The payload is externally mounted to the International Space Station truss to conduct experiments representative of future mission capability. Experiment operations include in-flight reconfiguration of the SDR waveform functions and payload networking software. The flight system will communicate with NASAs orbiting satellite relay network, the Tracking and Data Relay Satellite System at both S-band and Ka-band and to any Earth-based compatible S-band ground station. The system is available for experiments by industry, academia, and other government agencies to participate in the SDR technology assessments and standards advancements.

  7. Blind Signal Classification via Spare Coding

    DTIC Science & Technology

    2016-04-10

    recall and 14.1% false alarm. I. INTRODUCTION Cognitive radios have emerged over the last decade as a new means to share radio spectrum, the most...utility of radio spectrum resources. Much of contemporary research has viewed cognitive radios as the secondary user of a licensed channel and...the applica- bility of cognitive radios for tactical networking seems even more adequate. The primary advocate for tactical cognitive radio systems

  8. Academic Cross-Pollination: The Role of Disciplinary Affiliation in Research Collaboration

    PubMed Central

    Dhand, Amar; Luke, Douglas A.; Carothers, Bobbi J.; Evanoff, Bradley A.

    2016-01-01

    Academic collaboration is critical to knowledge production, especially as teams dominate scientific endeavors. Typical predictors of collaboration include individual characteristics such as academic rank or institution, and network characteristics such as a central position in a publication network. The role of disciplinary affiliation in the initiation of an academic collaboration between two investigators deserves more attention. Here, we examine the influence of disciplinary patterns on collaboration formation with control of known predictors using an inferential network model. The study group included all researchers in the Institute of Clinical and Translational Sciences (ICTS) at Washington University in St. Louis. Longitudinal data were collected on co-authorships in grants and publications before and after ICTS establishment. Exponential-family random graph models were used to build the network models. The results show that disciplinary affiliation independently predicted collaboration in grant and publication networks, particularly in the later years. Overall collaboration increased in the post-ICTS networks, with cross-discipline ties occurring more often than within-discipline ties in grants, but not publications. This research may inform better evaluation models of university-based collaboration, and offer a roadmap to improve cross-disciplinary collaboration with discipline-informed network interventions. PMID:26760302

  9. ARO PECASE: Information Assurance for Energy-Constrained Wireless Sensor Networks

    DTIC Science & Technology

    2011-12-21

    Distribution, 18th Annual IEEE International Symposium on Personal, Indoor, and Mobile Radio Communications (PIMRC), September 2007. 2. 2010 IEEE...received the following awards: Student Best Paper Award at the IEEE International Symposium on Personal, Indoor, and Mobile Radio Communications (PIMRC...Localization in Wireless Ad Hoc Networks – Many current and future appli- cations of mobile ad hoc networks, including disaster response and event

  10. Classifying Radio Galaxies with the Convolutional Neural Network

    NASA Astrophysics Data System (ADS)

    Aniyan, A. K.; Thorat, K.

    2017-06-01

    We present the application of a deep machine learning technique to classify radio images of extended sources on a morphological basis using convolutional neural networks (CNN). In this study, we have taken the case of the Fanaroff-Riley (FR) class of radio galaxies as well as radio galaxies with bent-tailed morphology. We have used archival data from the Very Large Array (VLA)—Faint Images of the Radio Sky at Twenty Centimeters survey and existing visually classified samples available in the literature to train a neural network for morphological classification of these categories of radio sources. Our training sample size for each of these categories is ˜200 sources, which has been augmented by rotated versions of the same. Our study shows that CNNs can classify images of the FRI and FRII and bent-tailed radio galaxies with high accuracy (maximum precision at 95%) using well-defined samples and a “fusion classifier,” which combines the results of binary classifications, while allowing for a mechanism to find sources with unusual morphologies. The individual precision is highest for bent-tailed radio galaxies at 95% and is 91% and 75% for the FRI and FRII classes, respectively, whereas the recall is highest for FRI and FRIIs at 91% each, while the bent-tailed class has a recall of 79%. These results show that our results are comparable to that of manual classification, while being much faster. Finally, we discuss the computational and data-related challenges associated with the morphological classification of radio galaxies with CNNs.

  11. Homeland Security: There’s an App for That

    DTIC Science & Technology

    2017-03-01

    bombings at the country’s train station and airport, mobile and terrestrial radio networks began to fail.5 The Belgian officers were using the mobile...suicide bombings at the country’s train station and airport, mobile and terrestrial radio networks began to fail. One officer deployed to the event...63 Alberts and Hayes, Power to the Edge, 199. 64 Thom Dick, “Will a Smartphone Replace Your Mobile Radio?” EMS World, July 1, 2016, http

  12. A Deep Space Network Portable Radio Science Receiver

    NASA Technical Reports Server (NTRS)

    Jongeling, Andre P.; Sigman, Elliott H.; Chandra, Kumar; Trinh, Joseph T.; Navarro, Robert; Rogstad, Stephen P.; Goodhart, Charles E.; Proctor, Robert C.; Finley, Susan G.; White, Leslie A.

    2009-01-01

    The Radio Science Receiver (RSR) is an open-loop receiver installed in NASA s Deep Space Network (DSN), which digitally filters and records intermediate-frequency (IF) analog signals. The RSR is an important tool for the Cassini Project, which uses it to measure perturbations of the radio-frequency wave as it travels between the spacecraft and the ground stations, allowing highly detailed study of the composition of the rings, atmosphere, and surface of Saturn and its satellites.

  13. The Telecommunications and Data Acquisition Report

    NASA Technical Reports Server (NTRS)

    Posner, E. C. (Editor)

    1985-01-01

    Deep Space Network (DSN) progress in flight project support, tracking and data acquisition research and technology, network engineering, hardware and software implementation, and operation is discussed. In addition, developments in Earth-based radio technology as applied to geodynamics, astrophysics and the radio search for extraterrestrial intelligence are reported.

  14. Structure and Evolution of Scientific Collaboration Networks in a Modern Research Collaboratory

    ERIC Educational Resources Information Center

    Pepe, Alberto

    2010-01-01

    This dissertation is a study of scientific collaboration at the Center for Embedded Networked Sensing (CENS), a modern, multi-disciplinary, distributed laboratory involved in sensor network research. By use of survey research and network analysis, this dissertation examines the collaborative ecology of CENS in terms of three networks of…

  15. RadioActive101 Practices

    ERIC Educational Resources Information Center

    Brites, Maria José; Ravenscroft, Andrew; Dellow, James; Rainey, Colin; Jorge, Ana; Santos, Sílvio Correia; Rees, Angela; Auwärter, Andreas; Catalão, Daniel; Balica, Magda; Camilleri, Anthony F.

    2014-01-01

    In keeping with the overarching RadioActive101 (RA101) spirit and ethos, this report is the product of collaborative and joined-up thinking from within the European consortium spread across five countries. As such, it is not simply a single voice reporting on the experiences and knowledge gained during the project. Rather it is a range of…

  16. Communication devices for network-hopping communications and methods of network-hopping communications

    DOEpatents

    Buttles, John W [Idaho Falls, ID

    2011-12-20

    Wireless communication devices include a software-defined radio coupled to processing circuitry. The processing circuitry is configured to execute computer programming code. Storage media is coupled to the processing circuitry and includes computer programming code configured to cause the processing circuitry to configure and reconfigure the software-defined radio to operate on each of a plurality of communication networks according to a selected sequence. Methods for communicating with a wireless device and methods of wireless network-hopping are also disclosed.

  17. Communication devices for network-hopping communications and methods of network-hopping communications

    DOEpatents

    Buttles, John W

    2013-04-23

    Wireless communication devices include a software-defined radio coupled to processing circuitry. The system controller is configured to execute computer programming code. Storage media is coupled to the system controller and includes computer programming code configured to cause the system controller to configure and reconfigure the software-defined radio to operate on each of a plurality of communication networks according to a selected sequence. Methods for communicating with a wireless device and methods of wireless network-hopping are also disclosed.

  18. Testing the Pairs-Reflection Model with X-Ray Spectral Variability and X-Ray Properties of Complete Samples of Radio-Selected BL Lacertae Objects

    NASA Astrophysics Data System (ADS)

    Urry, C. Megan

    1997-01-01

    This grant was awarded to Dr. C. Megan Urry of the Space Telescope Science Institute in response to two successful ADP proposals to use archival Ginga and Rosat X-ray data for 'Testing the Pairs-Reflection model with X-Ray Spectral Variability' (in collaboration with Paola Grandi, now at the University of Rome) and 'X-Ray Properties of Complete Samples of Radio-Selected BL Lacertae Objects' (in collaboration with then-graduate student Rita Sambruna, now a post-doc at Goddard Space Flight Center). In addition, post-docs Joseph Pesce and Elena Pian, and graduate student Matthew O'Dowd, have worked on several aspects of these projects. The grant was originally awarded on 3/01/94; this report covers the full period, through May 1997. We have completed our project on the X-ray properties of radio-selected BL Lacs.

  19. The Telecommunications and Data Acquisition Report

    NASA Technical Reports Server (NTRS)

    Posner, E. C. (Editor)

    1985-01-01

    Reports on developments in space communications, radio navigation, radio science, and ground-based radio astronomy are presented. Activities of the Deep Space Network (DSN) are reported in the areas of planning, supporting research and technology, implementation and operations. The application of radio interferometry at microwave frequencies for geodynamic measurements is also discussed.

  20. Multilayer Statistical Intrusion Detection in Wireless Networks

    NASA Astrophysics Data System (ADS)

    Hamdi, Mohamed; Meddeb-Makhlouf, Amel; Boudriga, Noureddine

    2008-12-01

    The rapid proliferation of mobile applications and services has introduced new vulnerabilities that do not exist in fixed wired networks. Traditional security mechanisms, such as access control and encryption, turn out to be inefficient in modern wireless networks. Given the shortcomings of the protection mechanisms, an important research focuses in intrusion detection systems (IDSs). This paper proposes a multilayer statistical intrusion detection framework for wireless networks. The architecture is adequate to wireless networks because the underlying detection models rely on radio parameters and traffic models. Accurate correlation between radio and traffic anomalies allows enhancing the efficiency of the IDS. A radio signal fingerprinting technique based on the maximal overlap discrete wavelet transform (MODWT) is developed. Moreover, a geometric clustering algorithm is presented. Depending on the characteristics of the fingerprinting technique, the clustering algorithm permits to control the false positive and false negative rates. Finally, simulation experiments have been carried out to validate the proposed IDS.

  1. Building Research Collaboration Networks--An Interpersonal Perspective for Research Capacity Building

    ERIC Educational Resources Information Center

    Huang, Jun Song

    2014-01-01

    While collaboration is increasingly recognized to be important for research, researchers' collaboration networks are still not adequately recognized as a form of research capacity in the literature. Research is a knowledge creation activity and interpersonal research collaboration networks are important for knowledge cross-fertilization and…

  2. Are We Alone? GAVRT Search for Extra Terrestrial Intelligence (SETI) Project

    NASA Astrophysics Data System (ADS)

    Bensel, Holly; Cool, Ian; St. Mary's High School Astronomy Club; St. Mary's Middle School Astronomy Club

    2017-01-01

    The Goldstone Apple Valley Radio Telescope Program (GAVRT) is a partnership between NASA’s Jet Propulsion Laboratory and the Lewis Center for Educational Research. The program is an authentic science investigation program for students in grades K through 12 and offers them the ability to learn how to be a part of a science team while they are making a real contribution to scientific knowledge.Using the internet from their classroom, students take control of a 34-meter decommissioned NASA radio telescope located at the Goldstone Deep Space Network complex in California. Students collect data on strong radio sources and work in collaboration with professional radio astronomers to analyze the data.Throughout history man has wondered if we were alone in the Universe. SETI - or the Search for Extra Terrestrial Intelligence - is one of the programs offered through GAVRT that is designed to help answer that question. By participating in SETI, students learn about science by doing real science and maybe, if they get very lucky, they might make the most important discovery of our lifetime: Intelligent life beyond Earth!At St. Mary’s School, students in grades 6-12 have participated in the project since its inception. The St. Mary’s Middle School Astronomy Club is leading the way in their relentless search for ET and radio telescope studies. Students use the radio telescope to select a very small portion of the Milky Way Galaxy - or galactic plane - and scan across it over and over in the hopes of finding a signal that is not coming from humans or radio interference. The possibility of being the first to discover an alien signal has kept some students searching for the past three years. For them to discover something of this magnitude is like winning the lottery: small chance of winning - big payoff. To that end, the club is focusing on several portions of the Milky Way where they have detected a strong candidate in the past. The hope is to pick it up a second and third time. If that happens, the club will be one step closer to proving intelligent life does exist.

  3. Value Co-creation and Co-innovation: Linking Networked Organisations and Customer Communities

    NASA Astrophysics Data System (ADS)

    Romero, David; Molina, Arturo

    Strategic networks such as Collaborative Networked Organisations (CNOs) and Virtual Customer Communities (VCCs) show a high potential as drivers of value co-creation and collaborative innovation in today’s Networking Era. Both look at the network structures as a source of jointly value creation and open innovation through access to new skills, knowledge, markets and technologies by sharing risk and integrating complementary competencies. This collaborative endeavour has proven to be able to enhance the adaptability and flexibility of CNOs and VCCs value creating systems in order to react in response to external drivers such as collaborative (business) opportunities. This paper presents a reference framework for creating interface networks, also known as ‘experience-centric networks’, as enablers for linking networked organisations and customer communities in order to support the establishment of user-driven and collaborative innovation networks.

  4. The telecommunications and data acquisition report

    NASA Technical Reports Server (NTRS)

    Renzetti, N. A. (Editor)

    1982-01-01

    Developments in Earth-based radio technology are reported. The Deep Space Network is discussed in terms of its advanced systems, network and facility engineering and implementation, operations, and energy sources. Problems in pulse communication and radio frequency interference are addressed with emphasis on pulse position modulation and laser beam collimation.

  5. Service collaboration and hospital cost performance: direct and moderating effects.

    PubMed

    Proenca, E Jose; Rosko, Michael D; Dismuke, Clara E

    2005-12-01

    Growing reliance on service provision through systems and networks creates the need to better understand the nature of the relationship between service collaboration and hospital performance and the conditions that affect this relationship. We examine 1) the effects of service provision through health systems and health networks on hospital cost performance and 2) the moderating effects of market conditions and service differentiation on the collaboration-cost relationship. We used moderated regression analysis to test the direct and moderating effects. Data on 1368 private hospitals came from the 1998 AHA Annual Survey, Medicare Cost Reports, and Solucient. Service collaboration was measured as the proportion of hospital services provided at the system level and at the network level. Market conditions were measured by the levels of managed care penetration and competition in the hospital's market. The proportion of hospital services provided at the system level had a negative relationship with hospital cost. The relationship was curvilinear for network use. Degree of managed care penetration moderated the relationship between network-based collaboration and hospital cost. The benefits of service collaboration through systems and networks, as measured by reduced cost, depend on degree of collaboration rather than mere membership. In loosely structured collaborations such as networks, costs reduce initially but increase later as the extent of collaboration increases. The effect of network-based collaboration is also tempered by managed care penetration. These effects are not seen in more tightly integrated forms such as systems.

  6. The Telecommunications and Data Acquisition Report

    NASA Technical Reports Server (NTRS)

    Posner, E. C. (Editor)

    1990-01-01

    Archival reports on developments in programs managed by the Jet Propulsion Laboratory's (JPL) Office of Telecommunications and Data Acquisition (TDA) are given. Space communications, radio navigation, radio science, and ground-based radio and radar astronomy, activities of the Deep Space Network (DSN) and its associated Ground Communications Facility (GCF) in planning, supporting research and technology, implementation, and operations are reported. Also included is TDA-funded activity at JPL on data and information systems and reimbursable Deep Space Network (DSN) work performed for other space agencies through NASA.

  7. Advanced Techniques of Artificial Networks Design for Radio Signal Detection

    NASA Astrophysics Data System (ADS)

    Danilin, S. N.; Shchanikov, S. A.; Iventev, A. A.; Zuev, A. D.

    2018-05-01

    This paper is concerned with the issue of secure radio communication of data between manned aircrafts, unmanned drones and control services. It is indicated that the use of artificial neural networks (ANN) enables correct identification of messages transmitted through radio channels and enhances identification quality by every measure. The authors designed and implemented a simulation modeling technology for ANN development, which enables signal detection with required accuracy in the context of noise jamming, natural and other types of noise.

  8. An energy-efficient and compact clustering scheme with temporary support nodes for cognitive radio sensor networks.

    PubMed

    Salim, Shelly; Moh, Sangman; Choi, Dongmin; Chung, Ilyong

    2014-08-11

    A cognitive radio sensor network (CRSN) is a wireless sensor network whose sensor nodes are equipped with cognitive radio capability. Clustering is one of the most challenging issues in CRSNs, as all sensor nodes, including the cluster head, have to use the same frequency band in order to form a cluster. However, due to the nature of heterogeneous channels in cognitive radio, it is difficult for sensor nodes to find a cluster head. This paper proposes a novel energy-efficient and compact clustering scheme named clustering with temporary support nodes (CENTRE). CENTRE efficiently achieves a compact cluster formation by adopting two-phase cluster formation with fixed duration. By introducing a novel concept of temporary support nodes to improve the cluster formation, the proposed scheme enables sensor nodes in a network to find a cluster head efficiently. The performance study shows that not only is the clustering process efficient and compact but it also results in remarkable energy savings that prolong the overall network lifetime. In addition, the proposed scheme decreases both the clustering overhead and the average distance between cluster heads and their members.

  9. An Energy-Efficient and Compact Clustering Scheme with Temporary Support Nodes for Cognitive Radio Sensor Networks

    PubMed Central

    Salim, Shelly; Moh, Sangman; Choi, Dongmin; Chung, Ilyong

    2014-01-01

    A cognitive radio sensor network (CRSN) is a wireless sensor network whose sensor nodes are equipped with cognitive radio capability. Clustering is one of the most challenging issues in CRSNs, as all sensor nodes, including the cluster head, have to use the same frequency band in order to form a cluster. However, due to the nature of heterogeneous channels in cognitive radio, it is difficult for sensor nodes to find a cluster head. This paper proposes a novel energy-efficient and compact clustering scheme named clustering with temporary support nodes (CENTRE). CENTRE efficiently achieves a compact cluster formation by adopting two-phase cluster formation with fixed duration. By introducing a novel concept of temporary support nodes to improve the cluster formation, the proposed scheme enables sensor nodes in a network to find a cluster head efficiently. The performance study shows that not only is the clustering process efficient and compact but it also results in remarkable energy savings that prolong the overall network lifetime. In addition, the proposed scheme decreases both the clustering overhead and the average distance between cluster heads and their members. PMID:25116905

  10. The benefits of convergence.

    PubMed

    Chang, Gee-Kung; Cheng, Lin

    2016-03-06

    A multi-tier radio access network (RAN) combining the strength of fibre-optic and radio access technologies employing adaptive microwave photonics interfaces and radio-over-fibre (RoF) techniques is envisioned for future heterogeneous wireless communications. All-band radio spectrum from 0.1 to 100 GHz will be used to deliver wireless services with high capacity, high link speed and low latency. The multi-tier RAN will improve the cell-edge performance in an integrated heterogeneous environment enabled by fibre-wireless integration and networking for mobile fronthaul/backhaul, resource sharing and all-layer centralization of multiple standards with different frequency bands and modulation formats. In essence, this is a 'no-more-cells' architecture in which carrier aggregation among multiple frequency bands can be easily achieved with seamless handover between cells. In this way, current and future mobile network standards such as 4G and 5G can coexist with optimized and continuous cell coverage using multi-tier RoF regardless of the underlying network topology or protocol. In terms of users' experience, the future-proof approach achieves the goals of system capacity, link speed, latency and continuous heterogeneous cell coverage while overcoming the bandwidth crunch in next-generation communication networks. © 2016 The Author(s).

  11. Providing QoS guarantee in 3G wireless networks

    NASA Astrophysics Data System (ADS)

    Chuah, MooiChoo; Huang, Min; Kumar, Suresh

    2001-07-01

    The third generation networks and services present opportunities to offer multimedia applications and services that meet end-to-end quality of service requirements. In this article, we present UMTS QoS architecture and its requirements. This includes the definition of QoS parameters, traffic classes, the end-to-end data delivery model, and the mapping of end-to-end services to the services provided by the network elements of the UMTS. End-to-end QoS of a user flow is achieved by the combination of the QoS control over UMTS Domain and the IP core Network. In the Third Generation Wireless network, UMTS bearer service manager is responsible to manage radio and transport resources to QoS-enabled applications. The UMTS bearer service consists of the Radio Access Bearer Service between Mobile Terminal and SGSN and Core Network bearer service between SGSN and GGSN. The Radio Access Bearer Service is further realized by the Radio Bearer Service (mostly air interface) and Iu bearer service. For the 3G air interface, one can provide differentiated QoS via intelligent burst allocation scheme, adaptive spreading factor control and weighted fair queueing scheduling algorithms. Next, we discuss the requirements for the transport technologies in the radio access network to provide differentiated QoS to multiple classes of traffic. We discuss both ATM based and IP based transport solutions. Last but not least, we discuss how QoS mechanism is provided in the core network to ensure e2e quality of service requirements. We discuss how mobile terminals that use RSVP as QoS signaling mechanisms can be are supported in the 3G network which may implement only IETF diffserv mechanism. . We discuss how one can map UMTS QoS classes with IETF diffserv code points. We also discuss 2G/3G handover scenarios and how the 2G/3G QoS parameters can be mapped.

  12. Key technologies and concepts for beyond-3G networks

    NASA Astrophysics Data System (ADS)

    Pehkonen, Kari; Uskela, Sami; Kalliojarvi, Kari; Oksanen, Lauri; Rikkinen, Kari

    2001-10-01

    Standardization of 3rd Generation (3G) mobile communication systems has produced the first specification releases and the commercial deployment of the 3G systems has started. Whereas 1G and 2G focused on efficiently providing voice services, in 3G a lot of attention has been devoted to solutions that support both Circuit Switched (CS) and Packet Switched (PS) communication. That has called for very flexible air interface and network solutions. 3G will continue to evolve and there are already on-going standardization activities that will, for example, boost the peak data rates up to 5-10 Mbps and improve spectral efficiency by 2-4 times. In the future, 3G evolution will be going towards 10/100 Mbps peak data rates in wide/local are coverage, respectively. This will take place partly because of technical improvements of 3G radio interface solutions, but also due to network evolution which will allow the integration other radio access methods like radio LANs into the 3G system. In longer term the 3G network evolution will be going towards ALL-IP networks. As 3G evolution seems to be going towards 10 Mbps/100 Mbps peak data rates and ALL-IP networks any beyond 3G air interface or network solution should be clearly better in order to justify its technical and commercial feasibility. Given the long evolution time of 3G and integration of other radio access schemes with 3G radio we may not even see a new, complete beyond 3G system being developed. Maybe we will just witness the emergence of a new, more advanced radio access solution which will then be connected to the evolving 3G network. As 3G evolution will continue for several years to come the research targets for any beyond 3G solutions must be set very high. When it comes to air interface, we should aim at 100 Mbps peak data rates for wide area access with high mobility, and at 1 Gbps for local area access with low mobility. Regarding possible commercial launches of any beyond 3G systems or solutions they could then take place around year 2010 or even later.

  13. Reputation-based collaborative network biology.

    PubMed

    Binder, Jean; Boue, Stephanie; Di Fabio, Anselmo; Fields, R Brett; Hayes, William; Hoeng, Julia; Park, Jennifer S; Peitsch, Manuel C

    2015-01-01

    A pilot reputation-based collaborative network biology platform, Bionet, was developed for use in the sbv IMPROVER Network Verification Challenge to verify and enhance previously developed networks describing key aspects of lung biology. Bionet was successful in capturing a more comprehensive view of the biology associated with each network using the collective intelligence and knowledge of the crowd. One key learning point from the pilot was that using a standardized biological knowledge representation language such as BEL is critical to the success of a collaborative network biology platform. Overall, Bionet demonstrated that this approach to collaborative network biology is highly viable. Improving this platform for de novo creation of biological networks and network curation with the suggested enhancements for scalability will serve both academic and industry systems biology communities.

  14. The Future of NASA's Deep Space Network and Applications to Planetary Probe Missions

    NASA Technical Reports Server (NTRS)

    Deutsch, Leslie J.; Preston, Robert A.; Vrotsos, Peter

    2010-01-01

    NASA's Deep Space Network (DSN) has been an invaluable tool in the world's exploration of space. It has served the space-faring community for more than 45 years. The DSN has provided a primary communication pathway for planetary probes, either through direct- to-Earth links or through intermediate radio relays. In addition, its radiometric systems are critical to probe navigation and delivery to target. Finally, the radio link can also be used for direct scientific measurement of the target body ('radio science'). This paper will examine the special challenges in supporting planetary probe missions, the future evolution of the DSN and related spacecraft technology, the advantages and disadvantages of radio relay spacecraft, and the use of the DSN radio links for navigation and scientific measurements.

  15. OMEGA SYSTEM SYNCHRONIZATION.

    DTIC Science & Technology

    TIME SIGNALS, * SYNCHRONIZATION (ELECTRONICS)), NETWORKS, FREQUENCY, STANDARDS, RADIO SIGNALS, ERRORS, VERY LOW FREQUENCY, PROPAGATION, ACCURACY, ATOMIC CLOCKS, CESIUM, RADIO STATIONS, NAVAL SHORE FACILITIES

  16. Classifying Radio Galaxies with the Convolutional Neural Network

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Aniyan, A. K.; Thorat, K.

    We present the application of a deep machine learning technique to classify radio images of extended sources on a morphological basis using convolutional neural networks (CNN). In this study, we have taken the case of the Fanaroff–Riley (FR) class of radio galaxies as well as radio galaxies with bent-tailed morphology. We have used archival data from the Very Large Array (VLA)—Faint Images of the Radio Sky at Twenty Centimeters survey and existing visually classified samples available in the literature to train a neural network for morphological classification of these categories of radio sources. Our training sample size for each of these categoriesmore » is ∼200 sources, which has been augmented by rotated versions of the same. Our study shows that CNNs can classify images of the FRI and FRII and bent-tailed radio galaxies with high accuracy (maximum precision at 95%) using well-defined samples and a “fusion classifier,” which combines the results of binary classifications, while allowing for a mechanism to find sources with unusual morphologies. The individual precision is highest for bent-tailed radio galaxies at 95% and is 91% and 75% for the FRI and FRII classes, respectively, whereas the recall is highest for FRI and FRIIs at 91% each, while the bent-tailed class has a recall of 79%. These results show that our results are comparable to that of manual classification, while being much faster. Finally, we discuss the computational and data-related challenges associated with the morphological classification of radio galaxies with CNNs.« less

  17. National College Radio Study: Audience Research and National Programming.

    ERIC Educational Resources Information Center

    Sauls, Samuel J.

    A study profiled college radio stations and explored the feasibility of a college radio network. A mail survey was sent in April 1995 to 1,469 college radio stations (including broadcast stations, carrier current stations, closed-circuit campus stations, radiating cable FM, and cable television access stations). A total of 228 surveys were…

  18. INSPIRE: A VLF Radio Project for High School Students

    ERIC Educational Resources Information Center

    Marshall, Jill A.; Pine, Bill; Taylor, William W. L.

    2007-01-01

    Since 1988 the Interactive NASA Space Physics Ionospheric Radio Experiment, or INSPIRE, has given students the opportunity to build research-quality VLF radio receivers and make observations of both natural and stimulated radio waves in the atmosphere. Any high school science class is eligible to join the INSPIRE volunteer observing network and…

  19. Automated isotope identification algorithm using artificial neural networks

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Kamuda, Mark; Stinnett, Jacob; Sullivan, Clair

    There is a need to develop an algorithm that can determine the relative activities of radio-isotopes in a large dataset of low-resolution gamma-ray spectra that contains a mixture of many radio-isotopes. Low-resolution gamma-ray spectra that contain mixtures of radio-isotopes often exhibit feature over-lap, requiring algorithms that can analyze these features when overlap occurs. While machine learning and pattern recognition algorithms have shown promise for the problem of radio-isotope identification, their ability to identify and quantify mixtures of radio-isotopes has not been studied. Because machine learning algorithms use abstract features of the spectrum, such as the shape of overlapping peaks andmore » Compton continuum, they are a natural choice for analyzing radio-isotope mixtures. An artificial neural network (ANN) has be trained to calculate the relative activities of 32 radio-isotopes in a spectrum. Furthermore, the ANN is trained with simulated gamma-ray spectra, allowing easy expansion of the library of target radio-isotopes. In this paper we present our initial algorithms based on an ANN and evaluate them against a series measured and simulated spectra.« less

  20. Automated isotope identification algorithm using artificial neural networks

    DOE PAGES

    Kamuda, Mark; Stinnett, Jacob; Sullivan, Clair

    2017-04-12

    There is a need to develop an algorithm that can determine the relative activities of radio-isotopes in a large dataset of low-resolution gamma-ray spectra that contains a mixture of many radio-isotopes. Low-resolution gamma-ray spectra that contain mixtures of radio-isotopes often exhibit feature over-lap, requiring algorithms that can analyze these features when overlap occurs. While machine learning and pattern recognition algorithms have shown promise for the problem of radio-isotope identification, their ability to identify and quantify mixtures of radio-isotopes has not been studied. Because machine learning algorithms use abstract features of the spectrum, such as the shape of overlapping peaks andmore » Compton continuum, they are a natural choice for analyzing radio-isotope mixtures. An artificial neural network (ANN) has be trained to calculate the relative activities of 32 radio-isotopes in a spectrum. Furthermore, the ANN is trained with simulated gamma-ray spectra, allowing easy expansion of the library of target radio-isotopes. In this paper we present our initial algorithms based on an ANN and evaluate them against a series measured and simulated spectra.« less

  1. The European Hands-On Universe project

    NASA Astrophysics Data System (ADS)

    Ferlet, Roger

    2012-07-01

    The EU-HOU project is a wide collaboration of teachers and scientists with the purpose of creating a way for pupils to get excited by science, primarily through the use of astronomy. EU-HOU gives pupils the chance to use real astronomical data to investigate research questions such as how to detect an extrasolar planet, identify the black hole at the center of the Milky Way, or discover the existence of dark matter. EU-HOU provides also the opportunity of real time sky observations through networks of robotic optical and radio telescopes via the Internet, together with pupil-friendly software to analyse the data. EU-HOU offers teachers incentives and advice through class-ready resources directly inspired from modern research, which can engage students in the wonder of scientific discovery and develop their creative thinking.

  2. DOE Office of Scientific and Technical Information (OSTI.GOV)

    Bordetsky, A; Dougan, A D; Nekoogar, F

    The paper addresses technological and operational challenges of developing a global plug-and-play Maritime Domain Security testbed for the Global War on Terrorism mission. This joint NPS-LLNL project is based on the NPS Tactical Network Topology (TNT) composed of long-haul OFDM networks combined with self-forming wireless mesh links to air, surface, ground, and underwater unmanned vehicles. This long-haul network is combined with ultra-wideband (UWB) communications systems for wireless communications in harsh radio propagation channels. LLNL's UWB communication prototypes are designed to overcome shortcomings of the present narrowband communications systems in heavy metallic and constricted corridors inside ships. In the center ofmore » our discussion are networking solutions for the Maritime Interdiction Operation (MIO) Experiments in which geographically distributed command centers and subject matter experts collaborate with the Boarding Party in real time to facilitate situational understanding and course of action selection. The most recent experiment conducted via the testbed extension to the Alameda Island exercised several key technologies aimed at improving MIO. These technologies included UWB communications from within the ship to Boarding Party leader sending data files and pictures, advanced radiation detection equipment for search and identification, biometric equipment to record and send fingerprint files to facilitate rapid positive identification of crew members, and the latest updates of the NPS Tactical Network Topology facilitating reachback to LLNL, Biometric Fusion Center, USCG, and DTRA experts.« less

  3. Designing a CTSA‐Based Social Network Intervention to Foster Cross‐Disciplinary Team Science

    PubMed Central

    McCarty, Christopher; Conlon, Michael; Nelson, David R.

    2015-01-01

    Abstract This paper explores the application of network intervention strategies to the problem of assembling cross‐disciplinary scientific teams in academic institutions. In a project supported by the University of Florida (UF) Clinical and Translational Science Institute, we used VIVO, a semantic‐web research networking system, to extract the social network of scientific collaborations on publications and awarded grants across all UF colleges and departments. Drawing on the notion of network interventions, we designed an alteration program to add specific edges to the collaboration network, that is, to create specific collaborations between previously unconnected investigators. The missing collaborative links were identified by a number of network criteria to enhance desirable structural properties of individual positions or the network as a whole. We subsequently implemented an online survey (N = 103) that introduced the potential collaborators to each other through their VIVO profiles, and investigated their attitudes toward starting a project together. We discuss the design of the intervention program, the network criteria adopted, and preliminary survey results. The results provide insight into the feasibility of intervention programs on scientific collaboration networks, as well as suggestions on the implementation of such programs to assemble cross‐disciplinary scientific teams in CTSA institutions. PMID:25788258

  4. Performance Evaluation and Comparative Analysis of SubCarrier Modulation Wake-up Radio Systems for Energy-Efficient Wireless Sensor Networks

    PubMed Central

    Oller, Joaquim; Demirkol, Ilker; Casademont, Jordi; Paradells, Josep; Gamm, Gerd Ulrich; Reindl, Leonhard

    2014-01-01

    Energy-efficient communication is one of the main concerns of wireless sensor networks nowadays. A commonly employed approach for achieving energy efficiency has been the use of duty-cycled operation of the radio, where the node's transceiver is turned off and on regularly, listening to the radio channel for possible incoming communication during its on-state. Nonetheless, such a paradigm performs poorly for scenarios of low or bursty traffic because of unnecessary activations of the radio transceiver. As an alternative technology, Wake-up Radio (WuR) systems present a promising energy-efficient network operation, where target devices are only activated in an on-demand fashion by means of a special radio signal and a WuR receiver. In this paper, we analyze a novel wake-up radio approach that integrates both data communication and wake-up functionalities into one platform, providing a reconfigurable radio operation. Through physical experiments, we characterize the delay, current consumption and overall operational range performance of this approach under different transmit power levels. We also present an actual single-hop WuR application scenario, as well as demonstrate the first true multi-hop capabilities of a WuR platform and simulate its performance in a multi-hop scenario. Finally, by thorough qualitative comparisons to the most relevant WuR proposals in the literature, we state that the proposed WuR system stands out as a strong candidate for any application requiring energy-efficient wireless sensor node communications. PMID:24451452

  5. Performance evaluation and comparative analysis of SubCarrier Modulation Wake-up Radio systems for energy-efficient wireless sensor networks.

    PubMed

    Oller, Joaquim; Demirkol, Ilker; Casademont, Jordi; Paradells, Josep; Gamm, Gerd Ulrich; Reindl, Leonhard

    2013-12-19

    Energy-efficient communication is one of the main concerns of wireless sensor networks nowadays. A commonly employed approach for achieving energy efficiency has been the use of duty-cycled operation of the radio, where the node's transceiver is turned off and on regularly, listening to the radio channel for possible incoming communication during its on-state. Nonetheless, such a paradigm performs poorly for scenarios of low or bursty traffic because of unnecessary activations of the radio transceiver. As an alternative technology, Wake-up Radio (WuR) systems present a promising energy-efficient network operation, where target devices are only activated in an on-demand fashion by means of a special radio signal and a WuR receiver. In this paper, we analyze a novel wake-up radio approach that integrates both data communication and wake-up functionalities into one platform, providing a reconfigurable radio operation. Through physical experiments, we characterize the delay, current consumption and overall operational range performance of this approach under different transmit power levels. We also present an actual single-hop WuR application scenario, as well as demonstrate the first true multi-hop capabilities of a WuR platform and simulate its performance in a multi-hop scenario. Finally, by thorough qualitative comparisons to the most relevant WuR proposals in the literature, we state that the proposed WuR system stands out as a strong candidate for any application requiring energy-efficient wireless sensor node communications.

  6. Identifying emerging research collaborations and networks: method development.

    PubMed

    Dozier, Ann M; Martina, Camille A; O'Dell, Nicole L; Fogg, Thomas T; Lurie, Stephen J; Rubinstein, Eric P; Pearson, Thomas A

    2014-03-01

    Clinical and translational research is a multidisciplinary, collaborative team process. To evaluate this process, we developed a method to document emerging research networks and collaborations in our medical center to describe their productivity and viability over time. Using an e-mail survey, sent to 1,620 clinical and basic science full- and part-time faculty members, respondents identified their research collaborators. Initial analyses, using Pajek software, assessed the feasibility of using social network analysis (SNA) methods with these data. Nearly 400 respondents identified 1,594 collaborators across 28 medical center departments resulting in 309 networks with 5 or more collaborators. This low-burden approach yielded a rich data set useful for evaluation using SNA to: (a) assess networks at several levels of the organization, including intrapersonal (individuals), interpersonal (social), organizational/institutional leadership (tenure and promotion), and physical/environmental (spatial proximity) and (b) link with other data to assess the evolution of these networks.

  7. GLOBECOM '87 - Global Telecommunications Conference, Tokyo, Japan, Nov. 15-18, 1987, Conference Record. Volumes 1, 2, & 3

    NASA Astrophysics Data System (ADS)

    The present conference on global telecommunications discusses topics in the fields of Integrated Services Digital Network (ISDN) technology field trial planning and results to date, motion video coding, ISDN networking, future network communications security, flexible and intelligent voice/data networks, Asian and Pacific lightwave and radio systems, subscriber radio systems, the performance of distributed systems, signal processing theory, satellite communications modulation and coding, and terminals for the handicapped. Also discussed are knowledge-based technologies for communications systems, future satellite transmissions, high quality image services, novel digital signal processors, broadband network access interface, traffic engineering for ISDN design and planning, telecommunications software, coherent optical communications, multimedia terminal systems, advanced speed coding, portable and mobile radio communications, multi-Gbit/second lightwave transmission systems, enhanced capability digital terminals, communications network reliability, advanced antimultipath fading techniques, undersea lightwave transmission, image coding, modulation and synchronization, adaptive signal processing, integrated optical devices, VLSI technologies for ISDN, field performance of packet switching, CSMA protocols, optical transport system architectures for broadband ISDN, mobile satellite communications, indoor wireless communication, echo cancellation in communications, and distributed network algorithms.

  8. Military Perspectives on Cyberpower

    DTIC Science & Technology

    2009-07-01

    PDAs) (such as the BlackBerry ), and global satellite and cable networks (including radio and TV), the impact of cyberspace on military operations has...phones, BlackBerries , telecoms, satellite and cable-based networks, radio, and TV. While it has developed the concepts of network-centric warfare to...domain may still be “outside the Maginot Line,” or may provide a tunnel to get under the line. Assuming that the line will be breached and the

  9. Software-Defined Radio Global System for Mobile Communications Transmitter Development for Heterogeneous Network Vulnerability Testing

    DTIC Science & Technology

    2013-12-01

    AbdelWahab, “ 2G / 3G Inter-RAT Handover Performance Analysis,” Second European Conference on Antennas and Propagation, pp. 1, 8, 11–16, Nov. 2007. [19] J...RADIO GLOBAL SYSTEM FOR MOBILE COMMUNICATIONS TRANSMITTER DEVELOPMENT FOR HETEROGENEOUS NETWORK VULNERABILITY TESTING by Carson C. McAbee... MOBILE COMMUNICATIONS TRANSMITTER DEVELOPMENT FOR HETEROGENEOUS NETWORK VULNERABILITY TESTING 5. FUNDING NUMBERS 6. AUTHOR(S) Carson C. McAbee

  10. Colonial modernity and networks in the Japanese empire: the role of Gotō Shinpei.

    PubMed

    Low, Morris

    2010-01-01

    This paper examines how Gotō Shinpei (1857-1929) sought to develop imperial networks emanating out of Tokyo in the fields of public health, railways, and communications. These areas helped define colonial modernity in the Japanese empire. In public health, Gotō's friendship with the bacteriologist Kitasato Shibasaburō led to the establishment of an Institute of Infectious Diseases in Tokyo. Key scientists from the institute took up positions in colonial medical colleges, creating a public health network that serviced the empire. Much of the empire itself was linked by a network of railways. Gotō was the first president of the South Manchuria Railway company (SMR). Communication technologies, especially radio, helped to bring the empire closer. By 1925, the Tokyo Broadcasting Station had begun its public radio broadcasts. Broadcasting soon came under the umbrella of the new organization, the Nippon Hōsō Kyōkai (NHK). Gotō was NHK's first president. The empire would soon be linked by radio, and it was by radio that Emperor Hirohito announced to the nation in 1945 that the empire had been lost.

  11. Process and data fragmentation-oriented enterprise network integration with collaboration modelling and collaboration agents

    NASA Astrophysics Data System (ADS)

    Li, Qing; Wang, Ze-yuan; Cao, Zhi-chao; Du, Rui-yang; Luo, Hao

    2015-08-01

    With the process of globalisation and the development of management models and information technology, enterprise cooperation and collaboration has developed from intra-enterprise integration, outsourcing and inter-enterprise integration, and supply chain management, to virtual enterprises and enterprise networks. Some midfielder enterprises begin to serve for different supply chains. Therefore, they combine related supply chains into a complex enterprise network. The main challenges for enterprise network's integration and collaboration are business process and data fragmentation beyond organisational boundaries. This paper reviews the requirements of enterprise network's integration and collaboration, as well as the development of new information technologies. Based on service-oriented architecture (SOA), collaboration modelling and collaboration agents are introduced to solve problems of collaborative management for service convergence under the condition of process and data fragmentation. A model-driven methodology is developed to design and deploy the integrating framework. An industrial experiment is designed and implemented to illustrate the usage of developed technologies in this paper.

  12. NASA Near Earth Network (NEN) Support for Lunar and L1/L2 CubeSats

    NASA Technical Reports Server (NTRS)

    Schaire, Scott; Altunc, Serhat; Wong, Yen; Shelton, Marta; Celeste, Peter; Anderson, Michael; Perrotto, Trish

    2017-01-01

    The NASA Near Earth Network (NEN) consists of globally distributed tracking stations, including NASA, commercial, and partner ground stations, that are strategically located to maximize the coverage provided to a variety of orbital and suborbital missions, including those in LEO, GEO, HEO, lunar and L1/L2 orbits. The NENs future mission set includes and will continue to include CubeSat missions. The majority of the CubeSat missions destined to fly on EM-1, launching in late 2018, many in a lunar orbit, will communicate with ground based stations via X-band and will utilize the NASA Jet Propulsion Laboratory (JPL) developed IRIS radio. The NEN recognizes the important role CubeSats are beginning to play in carrying out NASAs mission and is therefore investigating the modifications needed to provide IRIS radio compatibility. With modification, the NEN could potentially expand support to the EM-1 lunar CubeSats.The NEN could begin providing significant coverage to lunar CubeSat missions utilizing three to four of the NENs mid-latitude sites. This coverage would supplement coverage provided by the JPL Deep Space Network (DSN). The NEN, with smaller apertures than DSN, provides the benefit of a larger beamwidth that could be beneficial in the event of uncertain ephemeris data. In order to realize these benefits the NEN would need to upgrade stations targeted based on coverage ability and current configuration/ease of upgrade, to ensure compatibility with the IRIS radio. In addition, the NEN is working with CubeSat radio developers to ensure NEN compatibility with alternative CubeSat radios for Lunar and L1/L2 CubeSats. The NEN has provided NEN compatibility requirements to several radio developers who are developing radios that offer lower cost and, in some cases, more capabilities with fewer constraints. The NEN is ready to begin supporting CubeSat missions. The NEN is considering network upgrades to broaden the types of CubeSat missions that can be supported and is supporting both the CubeSat community and radio developers to ensure future CubeSat missions have multiple options when choosing a network for their communications support.

  13. The Challenges and Opportunities for International Cooperative Radio Science; Experience with Mars Express and Venus Express Missions

    NASA Technical Reports Server (NTRS)

    Holmes, Dwight P.; Thompson, Tommy; Simpson, Richard; Tyler, G. Leonard; Dehant, Veronique; Rosenblatt, Pascal; Hausler, Bernd; Patzold, Martin; Goltz, Gene; Kahan, Daniel; hide

    2008-01-01

    Radio Science is an opportunistic discipline in the sense that the communication link between a spacecraft and its supporting ground station can be used to probe the intervening media remotely. Radio science has recently expanded to greater, cooperative use of international assets. Mars Express and Venus Express are two such cooperative missions managed by the European Space Agency with broad international science participation supported by NASA's Deep Space Network (DSN) and ESA's tracking network for deep space missions (ESTRAK). This paper provides an overview of the constraints, opportunities, and lessons learned from international cross support of radio science, and it explores techniques for potentially optimizing the resultant data sets.

  14. The 'Moskva' satellite television broadcasting system

    NASA Astrophysics Data System (ADS)

    Kantor, L. Ia.; Minashin, V. P.; Povolotskii, I. S.; Sokolov, A. V.; Talyzin, N. V.

    1980-01-01

    The Moskva television broadcasting system which uses the high-power links from the Gorizont satellite is described. The transmitting device of the ground station is similar to that of the Ekran and Intersputnik systems. The system includes a special television signal processing unit, a unit for introducing dispersion signals, and transmitting equipment for the sound and radio-broadcasting channels. The signal translated by the satellite is received by a network of ground receiving stations and fed to a television transmitter with a power of 1, 10, or 100 W. The signal in the radio-broadcasting channel can be transmitted into the local radio repeater network or transmitted by a USW FM radio-broadcasting transmitter. The results of system tests are provided.

  15. A Framework for Implementing Virtual Collaborative Networks - Case Study on Automobile Components Production Industry

    NASA Astrophysics Data System (ADS)

    Parvinnia, Elham; Khayami, Raouf; Ziarati, Koorush

    Virtual collaborative networks are composed of small companies which take most advantage from the market opportunity and are able to compete with large companies. So some frameworks have been introduced for implementing this type of collaboration; although none of them has been standardized completely. In this paper we specify some instances that need to be standardized for implementing virtual enterprises. Then, a framework is suggested for implementing virtual collaborative networks. Finally, based on that suggestion, as a case study, we design a virtual collaborative network in automobile components production industry.

  16. Radio frequency sensing measurements and methods for location classification in wireless networks

    NASA Astrophysics Data System (ADS)

    Maas, Dustin C.

    The wireless radio channel is typically thought of as a means to move information from transmitter to receiver, but the radio channel can also be used to detect changes in the environment of the radio link. This dissertation is focused on the measurements we can make at the physical layer of wireless networks, and how we can use those measurements to obtain information about the locations of transceivers and people. The first contribution of this work is the development and testing of an open source, 802.11b sounder and receiver, which is capable of decoding packets and using them to estimate the channel impulse response (CIR) of a radio link at a fraction of the cost of traditional channel sounders. This receiver improves on previous implementations by performing optimized matched filtering on the field-programmable gate array (FPGA) of the Universal Software Radio Peripheral (USRP), allowing it to operate at full bandwidth. The second contribution of this work is an extensive experimental evaluation of a technology called location distinction, i.e., the ability to identify changes in radio transceiver position, via CIR measurements. Previous location distinction work has focused on single-input single-output (SISO) radio links. We extend this work to the context of multiple-input multiple-output (MIMO) radio links, and study system design trade-offs which affect the performance of MIMO location distinction. The third contribution of this work introduces the "exploiting radio windows" (ERW) attack, in which an attacker outside of a building surreptitiously uses the transmissions of an otherwise secure wireless network inside of the building to infer location information about people inside the building. This is possible because of the relative transparency of external walls to radio transmissions. The final contribution of this dissertation is a feasibility study for building a rapidly deployable radio tomographic (RTI) imaging system for special operations forces (SOF). We show that it is possible to obtain valuable tracking information using as few as 10 radios over a single floor of a typical suburban home, even without precise radio location measurements.

  17. How does network structure affect partnerships for promoting physical activity? Evidence from Brazil and Colombia.

    PubMed

    Parra, Diana C; Dauti, Marsela; Harris, Jenine K; Reyes, Lissette; Malta, Deborah C; Brownson, Ross C; Quintero, Mario A; Pratt, Michael

    2011-11-01

    The objective of this study was to describe the network structure and factors associated with collaboration in two networks that promote physical activity (PA) in Brazil and Colombia. Organizations that focus on studying and promoting PA in Brazil (35) and Colombia (53) were identified using a modified one-step reputational snowball sampling process. Participants completed an on-line survey between December 2008 and March 2009 for the Brazil network, and between April and June 2009 for the Colombia network. Network stochastic modeling was used to investigate the likelihood of reported inter-organizational collaboration. While structural features of networks were significant predictors of collaboration within each network, the coefficients and other network characteristics differed. Brazil's PA network was decentralized with a larger number of shared partnerships. Colombia's PA network was centralized and collaboration was influenced by perceived importance of peer organizations. On average, organizations in the PA network of Colombia reported facing more barriers (1.5 vs. 2.5 barriers) for collaboration. Future studies should focus on how these different network structures affect the implementation and uptake of evidence-based PA interventions. Copyright © 2011 Elsevier Ltd. All rights reserved.

  18. Multi-channel multi-radio using 802.11 based media access for sink nodes in wireless sensor networks.

    PubMed

    Campbell, Carlene E-A; Khan, Shafiullah; Singh, Dhananjay; Loo, Kok-Keong

    2011-01-01

    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.

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

    PubMed Central

    Campbell, Carlene E.-A.; Khan, Shafiullah; Singh, Dhananjay; Loo, Kok-Keong

    2011-01-01

    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. PMID:22163883

  20. Network effects on scientific collaborations.

    PubMed

    Uddin, Shahadat; Hossain, Liaquat; Rasmussen, Kim

    2013-01-01

    The analysis of co-authorship network aims at exploring the impact of network structure on the outcome of scientific collaborations and research publications. However, little is known about what network properties are associated with authors who have increased number of joint publications and are being cited highly. Measures of social network analysis, for example network centrality and tie strength, have been utilized extensively in current co-authorship literature to explore different behavioural patterns of co-authorship networks. Using three SNA measures (i.e., degree centrality, closeness centrality and betweenness centrality), we explore scientific collaboration networks to understand factors influencing performance (i.e., citation count) and formation (tie strength between authors) of such networks. A citation count is the number of times an article is cited by other articles. We use co-authorship dataset of the research field of 'steel structure' for the year 2005 to 2009. To measure the strength of scientific collaboration between two authors, we consider the number of articles co-authored by them. In this study, we examine how citation count of a scientific publication is influenced by different centrality measures of its co-author(s) in a co-authorship network. We further analyze the impact of the network positions of authors on the strength of their scientific collaborations. We use both correlation and regression methods for data analysis leading to statistical validation. We identify that citation count of a research article is positively correlated with the degree centrality and betweenness centrality values of its co-author(s). Also, we reveal that degree centrality and betweenness centrality values of authors in a co-authorship network are positively correlated with the strength of their scientific collaborations. Authors' network positions in co-authorship networks influence the performance (i.e., citation count) and formation (i.e., tie strength) of scientific collaborations.

  1. Implications of network structure on public health collaboratives.

    PubMed

    Retrum, Jessica H; Chapman, Carrie L; Varda, Danielle M

    2013-10-01

    Interorganizational collaboration is an essential function of public health agencies. These partnerships form social networks that involve diverse types of partners and varying levels of interaction. Such collaborations are widely accepted and encouraged, yet very little comparative research exists on how public health partnerships develop and evolve, specifically in terms of how subsequent network structures are linked to outcomes. A systems science approach, that is, one that considers the interdependencies and nested features of networks, provides the appropriate methods to examine the complex nature of these networks. Applying Mays and Scutchfields's categorization of "structural signatures" (breadth, density, and centralization), this research examines how network structure influences the outcomes of public health collaboratives. Secondary data from the Program to Analyze, Record, and Track Networks to Enhance Relationships (www.partnertool.net) data set are analyzed. This data set consists of dyadic (N = 12,355), organizational (N = 2,486), and whole network (N = 99) data from public health collaborations around the United States. Network data are used to calculate structural signatures and weighted least squares regression is used to examine how network structures can predict selected intermediary outcomes (resource contributions, overall value and trust rankings, and outcomes) in public health collaboratives. Our findings suggest that network structure may have an influence on collaborative-related outcomes. The structural signature that had the most significant relationship to outcomes was density, with higher density indicating more positive outcomes. Also significant was the finding that more breadth creates new challenges such as difficulty in reaching consensus and creating ties with other members. However, assumptions that these structural components lead to improved outcomes for public health collaboratives may be slightly premature. Implications of these findings for research and practice are discussed.

  2. Research in the Aloha system

    NASA Technical Reports Server (NTRS)

    Abramson, N.

    1974-01-01

    The Aloha system was studied and developed and extended to advanced forms of computer communications networks. Theoretical and simulation studies of Aloha type radio channels for use in packet switched communications networks were performed. Improved versions of the Aloha communications techniques and their extensions were tested experimentally. A packet radio repeater suitable for use with the Aloha system operational network was developed. General studies of the organization of multiprocessor systems centered on the development of the BCC 500 computer were concluded.

  3. Detecting and analyzing research communities in longitudinal scientific networks.

    PubMed

    Leone Sciabolazza, Valerio; Vacca, Raffaele; Kennelly Okraku, Therese; McCarty, Christopher

    2017-01-01

    A growing body of evidence shows that collaborative teams and communities tend to produce the highest-impact scientific work. This paper proposes a new method to (1) Identify collaborative communities in longitudinal scientific networks, and (2) Evaluate the impact of specific research institutes, services or policies on the interdisciplinary collaboration between these communities. First, we apply community-detection algorithms to cross-sectional scientific collaboration networks and analyze different types of co-membership in the resulting subgroups over time. This analysis summarizes large amounts of longitudinal network data to extract sets of research communities whose members have consistently collaborated or shared collaborators over time. Second, we construct networks of cross-community interactions and estimate Exponential Random Graph Models to predict the formation of interdisciplinary collaborations between different communities. The method is applied to longitudinal data on publication and grant collaborations at the University of Florida. Results show that similar institutional affiliation, spatial proximity, transitivity effects, and use of the same research services predict higher degree of interdisciplinary collaboration between research communities. Our application also illustrates how the identification of research communities in longitudinal data and the analysis of cross-community network formation can be used to measure the growth of interdisciplinary team science at a research university, and to evaluate its association with research policies, services or institutes.

  4. Detecting and analyzing research communities in longitudinal scientific networks

    PubMed Central

    Vacca, Raffaele; Kennelly Okraku, Therese; McCarty, Christopher

    2017-01-01

    A growing body of evidence shows that collaborative teams and communities tend to produce the highest-impact scientific work. This paper proposes a new method to (1) Identify collaborative communities in longitudinal scientific networks, and (2) Evaluate the impact of specific research institutes, services or policies on the interdisciplinary collaboration between these communities. First, we apply community-detection algorithms to cross-sectional scientific collaboration networks and analyze different types of co-membership in the resulting subgroups over time. This analysis summarizes large amounts of longitudinal network data to extract sets of research communities whose members have consistently collaborated or shared collaborators over time. Second, we construct networks of cross-community interactions and estimate Exponential Random Graph Models to predict the formation of interdisciplinary collaborations between different communities. The method is applied to longitudinal data on publication and grant collaborations at the University of Florida. Results show that similar institutional affiliation, spatial proximity, transitivity effects, and use of the same research services predict higher degree of interdisciplinary collaboration between research communities. Our application also illustrates how the identification of research communities in longitudinal data and the analysis of cross-community network formation can be used to measure the growth of interdisciplinary team science at a research university, and to evaluate its association with research policies, services or institutes. PMID:28797047

  5. Designing a CTSA-Based Social Network Intervention to Foster Cross-Disciplinary Team Science.

    PubMed

    Vacca, Raffaele; McCarty, Christopher; Conlon, Michael; Nelson, David R

    2015-08-01

    This paper explores the application of network intervention strategies to the problem of assembling cross-disciplinary scientific teams in academic institutions. In a project supported by the University of Florida (UF) Clinical and Translational Science Institute, we used VIVO, a semantic-web research networking system, to extract the social network of scientific collaborations on publications and awarded grants across all UF colleges and departments. Drawing on the notion of network interventions, we designed an alteration program to add specific edges to the collaboration network, that is, to create specific collaborations between previously unconnected investigators. The missing collaborative links were identified by a number of network criteria to enhance desirable structural properties of individual positions or the network as a whole. We subsequently implemented an online survey (N = 103) that introduced the potential collaborators to each other through their VIVO profiles, and investigated their attitudes toward starting a project together. We discuss the design of the intervention program, the network criteria adopted, and preliminary survey results. The results provide insight into the feasibility of intervention programs on scientific collaboration networks, as well as suggestions on the implementation of such programs to assemble cross-disciplinary scientific teams in CTSA institutions. © 2015 Wiley Periodicals, Inc.

  6. Preparing the Plate Boundary Observatory GNSS Network for the Future

    NASA Astrophysics Data System (ADS)

    Austin, K. E.; Walls, C. P.; Dittman, T.; Mann, D.; Boyce, E. S.; Basset, A.; Woolace, A. C.; Turner, R.; Lawrence, S.; Rhoades, S.; Pyatt, C.; Willoughby, H.; Feaux, K.; Mattioli, G. S.

    2017-12-01

    The EarthScope Plate Boundary Observatory (PBO) GNSS network, funded by the NSF and operated by UNAVCO, is comprised of 1100 permanent GPS and GNSS stations spanning three principal tectonic regimes and is administered by distinct management. The GPS-only network was initially designed for daily data file downloads primarily for tectonic analysis. This low data volume requirement and circa-2004 IP-based cellular/VSat modems provided significant freedom for station placement and enabled science-targeted installation of stations in some of the most remote and geologically interesting areas. Community requests for high-rate data downloads for GNSS seismology, airborne LiDAR surveys, meteorological/GNSS/seismic real-time data flow and other demands, however, require significantly increased bandwidth beyond the 5-20 kB/s transfer rates that were needed as part of the original design. Since the close of construction in September 2008, PBO enhancements have been implemented through additional funding by the NSF (ARRA/Cascadia), NOAA, and NASA and in collaboration with stakeholders such as Caltrans, ODOT, Scripps, and the USGS. Today, only 18 of the original cell modems remain, with 601 upgraded cell modems providing 3G/4G/LTE data communications that support transfer rates ranging from 80-400 kB/s. Radio network expansion and upgrades continue to harden communications using both 2.4 GHz and 5.8 GHz radios. 78 VSAT and 5 manual download sites remain. PBO-wide the network capabilities for 1 Hz & 5 Hz downloads or low latency 1 Hz streaming are 85%, 80% and 65% of PBO stations, respectively, with 708 active 1 Hz streams. Vaisala meteorological instruments are located at 140 sites most of which stream GPS/Met data in real time. GPS-only receivers are being replaced with GNSS receivers and antennas. Today, there are 279 stations in the PBO network with either GLONASS enabled Trimble NetR9 or full GNSS constellation Septentrio PolaRx5 receivers. Just as the scale and geographical density of the PBO project has opened up new and unexpected avenues for geophysical research across disciplines (e.g. atmosphere, meteorology, snow pack, tides, vegetation growth, drought monitoring, etc.), the coming decade under the NGEO banner will undoubtedly present new opportunities as the network continues to be modernized.

  7. [Scientific production in clinical medicine and international collaboration networks in South American countries].

    PubMed

    Huamaní, Charles; González A, Gregorio; Curioso, Walter H; Pacheco-Romero, José

    2012-04-01

    International collaboration is increasingly used in biomedical research. To describe the characteristics of scientific production in Latin America and the main international collaboration networks for the period 2000 to 2009. Search for papers generated in Latin American countries in the Clinical Medicine database of ISI Web of Knowledge v.4.10 - Current Contents Connect. The country of origin of the corresponding author was considered the producing country of the paper. International collaboration was analyzed calculating the number of countries that contributed to the generation of a particular paper. Collaboration networks were graphed to determine the centrality of each network. Twelve Latin American countries participated in the production of 253,362 papers. The corresponding author was South American in 79% of these papers. Sixteen percent of papers were on clinical medicine and 36% of these were carried out in collaboration. Brazil had the highest production (22,442 papers) and the lower percentage of international collaboration (31%). North America accounts for 63% of collaborating countries. Only 8% of collaboration is between South American countries. Brazil has the highest tendency to collaborate with other South American countries. Brazil is the South American country with the highest scientific production and indicators of centrality in South America. The most common collaboration networks are with North American countries.

  8. The Telecommunications and Data Acquisition Report

    NASA Technical Reports Server (NTRS)

    Posner, E. C. (Editor)

    1986-01-01

    This publication, one of a series formerly titled The Deep Space Network (DSN) Progress Report, documents DSN progress in flight project support, tracking and data acquisition research and technology, network engineering, hardware and software implementation, and operations. In addition, developments in Earth-based radio technology as applied to geodynamics, astrophysics, and the radio search for extraterrestrial intelligence are reported.

  9. The Telecommunications and Data Acquisition Report

    NASA Technical Reports Server (NTRS)

    Posner, E. C. (Editor)

    1984-01-01

    Activities in space communication, radio navigation, radio science, and ground-based astronomy are reported. Advanced systems for the Deep Space Network and its Ground-Communications Facility are discussed including station control and system technology. Network sustaining as well as data and information systems are covered. Studies of geodynamics, investigations of the microwave spectrum, and the search for extraterrestrial intelligence are reported.

  10. The Telecommunications and Data Acquisition Report

    NASA Technical Reports Server (NTRS)

    Posner, E. C. (Editor)

    1988-01-01

    This publication, one of a series formerly titled The Deep Space Network Progress Report, documents DSN progress in flight project support, tracking and data acquisition research and technology, network engineering, hardware and software implementation, and operations. In addition, developments in earth-based radio technology as applied to geodynamics, astrophysics, and the radio search for extraterrestrial intelligence are reported.

  11. Radio Electioneering in the American Presidential Campaigns of 1932 and 1936.

    ERIC Educational Resources Information Center

    Nicolaides, Becky M.

    1988-01-01

    Presents a study which focuses on the use of network radio in the presidential campaigns of 1932 and 1936. Discusses the use of performance skills and sales techniques in broadcasts made by the Democrats and Republicans over the two major networks: the Columbia Broadcasting System and the National Broadcasting System. Examines how radio…

  12. Mathematical modeling of a radio-frequency path for IEEE 802.11ah based wireless sensor networks

    NASA Astrophysics Data System (ADS)

    Tyshchenko, Igor; Cherepanov, Alexander; Dmitrii, Vakhnin; Popova, Mariia

    2017-09-01

    This article discusses the process of creating the mathematical model of a radio-frequency path for an IEEE 802.11ah based wireless sensor networks using M atLab Simulink CAD tools. In addition, it describes occurring perturbing effects and determining the presence of a useful signal in the received mixture.

  13. Portable control device for networked mobile robots

    DOEpatents

    Feddema, John T.; Byrne, Raymond H.; Bryan, Jon R.; Harrington, John J.; Gladwell, T. Scott

    2002-01-01

    A handheld control device provides a way for controlling one or multiple mobile robotic vehicles by incorporating a handheld computer with a radio board. The device and software use a personal data organizer as the handheld computer with an additional microprocessor and communication device on a radio board for use in controlling one robot or multiple networked robots.

  14. 11 CFR 100.29 - Electioneering communication (2 U.S.C. 434(f)(3)).

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... more; or (C) In the case of a communication transmitted by an AM radio broadcast station or network... case of a communication transmitted by an AM radio broadcast station or network, where a portion of the... requirements described in 11 CFR 100.132(a) and (b); (3) Constitutes an expenditure or independent expenditure...

  15. 11 CFR 100.29 - Electioneering communication (2 U.S.C. 434(f)(3)).

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... more; or (C) In the case of a communication transmitted by an AM radio broadcast station or network... case of a communication transmitted by an AM radio broadcast station or network, where a portion of the... requirements described in 11 CFR 100.132(a) and (b); (3) Constitutes an expenditure or independent expenditure...

  16. 11 CFR 100.29 - Electioneering communication (2 U.S.C. 434(f)(3)).

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... more; or (C) In the case of a communication transmitted by an AM radio broadcast station or network... case of a communication transmitted by an AM radio broadcast station or network, where a portion of the... requirements described in 11 CFR 100.132(a) and (b); (3) Constitutes an expenditure or independent expenditure...

  17. The Telecommunications and Data Acquisition Report

    NASA Technical Reports Server (NTRS)

    Posner, E. C. (Editor)

    1992-01-01

    Archival reports on developments in programs managed by JPL's Office of Telecommunications and Data Acquisition (TDA) are provided. In space communications, radio navigation, radio science, and ground-based radio and radar astronomy, it reports on activities of the Deep Space Network (DSN) in planning, in supporting research and technology, in implementation, and in operations. Also included is standards activity at JPL for space data and information. In the search for extraterrestrial intelligence (SETI), the TDA Progress Report reports on implementation and operations for searching the microwave spectrum. Topics covered include tracking and ground-based navigation; communications, spacecraft-ground; station control and system technology; capabilities for new projects; network upgrade and sustaining; network operations and operations support; and TDA program management and analysis.

  18. Cascaded neural networks for sequenced propagation estimation, multiuser detection, and adaptive radio resource control of third-generation wireless networks for multimedia services

    NASA Astrophysics Data System (ADS)

    Hortos, William S.

    1999-03-01

    A hybrid neural network approach is presented to estimate radio propagation characteristics and multiuser interference and to evaluate their combined impact on throughput, latency and information loss in third-generation (3G) wireless networks. The latter three performance parameters influence the quality of service (QoS) for multimedia services under consideration for 3G networks. These networks, based on a hierarchical architecture of overlaying macrocells on top of micro- and picocells, are planned to operate in mobile urban and indoor environments with service demands emanating from circuit-switched, packet-switched and satellite-based traffic sources. Candidate radio interfaces for these networks employ a form of wideband CDMA in 5-MHz and wider-bandwidth channels, with possible asynchronous operation of the mobile subscribers. The proposed neural network (NN) architecture allocates network resources to optimize QoS metrics. Parameters of the radio propagation channel are estimated, followed by control of an adaptive antenna array at the base station to minimize interference, and then joint multiuser detection is performed at the base station receiver. These adaptive processing stages are implemented as a sequence of NN techniques that provide their estimates as inputs to a final- stage Kohonen self-organizing feature map (SOFM). The SOFM optimizes the allocation of available network resources to satisfy QoS requirements for variable-rate voice, data and video services. As the first stage of the sequence, a modified feed-forward multilayer perceptron NN is trained on the pilot signals of the mobile subscribers to estimate the parameters of shadowing, multipath fading and delays on the uplinks. A recurrent NN (RNN) forms the second stage to control base stations' adaptive antenna arrays to minimize intra-cell interference. The third stage is based on a Hopfield NN (HNN), modified to detect multiple users on the uplink radio channels to mitigate multiaccess interference, control carrier-sense multiple-access (CSMA) protocols, and refine call handoff procedures. In the final stage, the Kohonen SOFM, operating in a hybrid continuous and discrete space, adaptively allocates the resources of antenna-based cell sectorization, activity monitoring, variable-rate coding, power control, handoff and caller admission to meet user demands for various multimedia services at minimum QoS levels. The performance of the NN cascade is evaluated through simulation of a candidate 3G wireless network using W-CDMA parameters in a small-cell environment. The simulated network consists of a representative number of cells. Mobile users with typical movement patterns are assumed. QoS requirements for different classes of multimedia services are considered. The proposed method is shown to provide relatively low probability of new call blocking and handoff dropping, while maintaining efficient use of the network's radio resources.

  19. A Survey of MAC Protocols for Cognitive Radio Body Area Networks.

    PubMed

    Bhandari, Sabin; Moh, Sangman

    2015-04-20

    The advancement in electronics, wireless communications and integrated circuits has enabled the development of small low-power sensors and actuators that can be placed on, in or around the human body. A wireless body area network (WBAN) can be effectively used to deliver the sensory data to a central server, where it can be monitored, stored and analyzed. For more than a decade, cognitive radio (CR) technology has been widely adopted in wireless networks, as it utilizes the available spectra of licensed, as well as unlicensed bands. A cognitive radio body area network (CRBAN) is a CR-enabled WBAN. Unlike other wireless networks, CRBANs have specific requirements, such as being able to automatically sense their environments and to utilize unused, licensed spectra without interfering with licensed users, but existing protocols cannot fulfill them. In particular, the medium access control (MAC) layer plays a key role in cognitive radio functions, such as channel sensing, resource allocation, spectrum mobility and spectrum sharing. To address various application-specific requirements in CRBANs, several MAC protocols have been proposed in the literature. In this paper, we survey MAC protocols for CRBANs. We then compare the different MAC protocols with one another and discuss challenging open issues in the relevant research.

  20. VLA radio upper limit on Type IIn Supernova 2008S

    NASA Astrophysics Data System (ADS)

    Chandra, Poonam; Soderberg, Alicia

    2008-02-01

    Poonam Chandra and Alicia Soderberg report on behalf of a larger collaboration: We observed type IIn supernova SN 2008S (CBET 1234) with the Very Large Array (VLA) on 2008, February 10.62 UT. We do not detect any radio emission at the supernova position (CBET 1234). The flux density at the supernova position is -62 +/- 36 uJy.

  1. An Overview of Geodetic and Astrometric VLBI at the Hartebeesthoek Radio Astronomy Observatory

    NASA Astrophysics Data System (ADS)

    de Witt, A.; Gaylard, M.; Quick, J.; Combrinck, L.

    2013-08-01

    For astronomical Very Long Baseline Interferometry (VLBI), the Hartebeesthoek Radio Astronomy Observatory (HartRAO), in South Africa operates as part of a number of networks including the European and Australian VLBI networks, global arrays and also space VLBI. HartRAO is the only African representative in the international geodetic VLBI network and participates in regular astrometric and geodetic VLBI programmes. HartRAO will play a major role in the realization of the next generation full-sky celestial reference frame, especially the improvement of the celestial reference frame in the South. The observatory also provides a base for developing the African VLBI Network (AVN), a project to convert redundant satellite Earth-station antennas across Africa to use for radio astronomy. The AVN would greatly facilitate VLBI observations of southern objects. We present an overview of the current capabilities as well as future opportunities for astrometric and geodetic VLBI at HartRAO.

  2. Security-Enhanced Autonomous Network Management

    NASA Technical Reports Server (NTRS)

    Zeng, Hui

    2015-01-01

    Ensuring reliable communication in next-generation space networks requires a novel network management system to support greater levels of autonomy and greater awareness of the environment and assets. Intelligent Automation, Inc., has developed a security-enhanced autonomous network management (SEANM) approach for space networks through cross-layer negotiation and network monitoring, analysis, and adaptation. The underlying technology is bundle-based delay/disruption-tolerant networking (DTN). The SEANM scheme allows a system to adaptively reconfigure its network elements based on awareness of network conditions, policies, and mission requirements. Although SEANM is generically applicable to any radio network, for validation purposes it has been prototyped and evaluated on two specific networks: a commercial off-the-shelf hardware test-bed using Institute of Electrical Engineers (IEEE) 802.11 Wi-Fi devices and a military hardware test-bed using AN/PRC-154 Rifleman Radio platforms. Testing has demonstrated that SEANM provides autonomous network management resulting in reliable communications in delay/disruptive-prone environments.

  3. Networked Leadership in Educational Collaborative Networks

    ERIC Educational Resources Information Center

    Díaz-Gibson, Jordi; Zaragoza, Mireia Civís; Daly, Alan J.; Mayayo, Jordi Longás; Romaní, Jordi Riera

    2017-01-01

    Educational Collaborative Networks (ECNs) aim to achieve educational goals at the community level and base their actions on collaborative partnering between schools and community organizations. These approaches are an emergent and innovative leadership and policy strategy being used increasingly across the globe, given the interconnected and…

  4. 77 FR 32141 - Privacy Act of 1974, as Amended; System of Records Notices

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-05-31

    ... records titled ``Internal Collaboration Network''. SUMMARY: The National Archives and Records... 43, the Internal Collaboration Network, which contains files with information on National Archives.... SUPPLEMENTARY INFORMATION: The Internal Collaboration Network is a web- based platform that allows users to...

  5. Competition in collaborative clothing: a qualitative case study of influences on collaborative quality improvement in the ICU.

    PubMed

    Dainty, Katie N; Scales, Damon C; Sinuff, Tasnim; Zwarenstein, Merrick

    2013-04-01

    Multiorganisational quality improvement (QI) collaborative networks are promoted for improving quality within healthcare. Recently, several large-scale QI initiatives have been conducted in the intensive care unit (ICU) environment with successful quantitative results. However, the mechanisms through which such networks lead to QI success remain uncertain. We aim to understand ICU staff perspectives on collaborative QI based on involvement in a multiorganisational improvement network and hypothesise about theoretical constructs that might explain the effect of collaboration in such networks. Qualitative study using a modified grounded theory approach. Key informant interviews were conducted with staff from 12 community hospital ICUs that participated in a cluster randomized control trial (RCT) of a QI intervention using a collaborative approach between 2006 and 2008. Data analysis followed the standard procedure for grounded theory using constant comparative methodology. The collaborative network was perceived to promote increased intrateam cooperation over interorganisational cooperation, but friendly competition with other ICUs appeared to be a prominent driver of behaviour change. Bedsides, clinicians reported that belonging to a collaborative network provided recognition for the high-quality patient care that they already provided. However, the existing communication structure was perceived to be ineffective for staff engagement since it was based on a hierarchical approach to knowledge transfer and project awareness. QI collaborative networks may promote behaviour change by improving intrateam communication, fostering competition with other institutions, and increasing recognition for providing high-quality care. Other commonly held assumptions about their potential impact, for instance, increasing interorganisational legitimisation, communication and collaboration, may be less important.

  6. Sensors Locate Radio Interference

    NASA Technical Reports Server (NTRS)

    2009-01-01

    After receiving a NASA Small Business Innovation Research (SBIR) contract from Kennedy Space Center, Soneticom Inc., based in West Melbourne, Florida, created algorithms for time difference of arrival and radio interferometry, which it used in its Lynx Location System (LLS) to locate electromagnetic interference that can disrupt radio communications. Soneticom is collaborating with the Federal Aviation Administration (FAA) to install and test the LLS at its field test center in New Jersey in preparation for deploying the LLS at commercial airports. The software collects data from each sensor in order to compute the location of the interfering emitter.

  7. Radio astronomy

    NASA Technical Reports Server (NTRS)

    Taylor, R. M.; Manchester, R. N.

    1980-01-01

    The activities of the Deep Space Network in support of radio and radar astronomy operations during July and August 1980 are reported. A brief update on the OSS-sponsored planetary radio astronomy experiment is provided. Also included are two updates, one each from Spain and Australia on current host country activities.

  8. Mapping the Growing Discipline of Dissemination and Implementation Science in Health

    PubMed Central

    Norton, Wynne E.; Lungeanu, Alina; Chambers, David A.; Contractor, Noshir

    2017-01-01

    Background The field of dissemination and implementation (D&I) research in health has grown considerably in the past decade. Despite the potential for advancing the science, limited research has focused on mapping the field. Methods We administered an online survey to individuals in the D&I field to assess participants’ demographics and expertise, as well as engagement with journals and conferences, publications, and grants. A combined roster–nomination method was used to collect data on participants’ advice networks and collaboration networks; participants’ motivations for choosing collaborators was also assessed. Frequency and descriptive statistics were used to characterize the overall sample; network metrics were used to characterize both networks. Among a sub-sample of respondents who were researchers, regression analyses identified predictors of two metrics of academic performance (i.e., publications and funded grants). Results A total of 421 individuals completed the survey, representing a 30.75% response rate of eligible individuals. Most participants were White (n = 343), female (n = 284, 67.4%), and identified as a researcher (n = 340, 81%). Both the advice and the collaboration networks displayed characteristics of a small world network. The most important motivations for selecting collaborators were aligned with advancing the science (i.e., prior collaborators, strong reputation, and good collaborators) rather than relying on human proclivities for homophily, proximity, and friendship. Among a sub-sample of 295 researchers, expertise (individual predictor), status (advice network), and connectedness (collaboration network) were significant predictors of both metrics of academic performance. Conclusions Network-based interventions can enhance collaboration and productivity; future research is needed to leverage these data to advance the field. PMID:29249842

  9. Mapping the Growing Discipline of Dissemination and Implementation Science in Health.

    PubMed

    Norton, Wynne E; Lungeanu, Alina; Chambers, David A; Contractor, Noshir

    2017-09-01

    The field of dissemination and implementation (D&I) research in health has grown considerably in the past decade. Despite the potential for advancing the science, limited research has focused on mapping the field. We administered an online survey to individuals in the D&I field to assess participants' demographics and expertise, as well as engagement with journals and conferences, publications, and grants. A combined roster-nomination method was used to collect data on participants' advice networks and collaboration networks; participants' motivations for choosing collaborators was also assessed. Frequency and descriptive statistics were used to characterize the overall sample; network metrics were used to characterize both networks. Among a sub-sample of respondents who were researchers, regression analyses identified predictors of two metrics of academic performance (i.e., publications and funded grants). A total of 421 individuals completed the survey, representing a 30.75% response rate of eligible individuals. Most participants were White (n = 343), female (n = 284, 67.4%), and identified as a researcher (n = 340, 81%). Both the advice and the collaboration networks displayed characteristics of a small world network. The most important motivations for selecting collaborators were aligned with advancing the science (i.e., prior collaborators, strong reputation, and good collaborators) rather than relying on human proclivities for homophily, proximity, and friendship. Among a sub-sample of 295 researchers, expertise (individual predictor), status (advice network), and connectedness (collaboration network) were significant predictors of both metrics of academic performance. Network-based interventions can enhance collaboration and productivity; future research is needed to leverage these data to advance the field.

  10. Involvement, Collaboration and Engagement: Social Networks through a Pedagogical Lens

    ERIC Educational Resources Information Center

    Seifert, Tami

    2016-01-01

    Social networks facilitate activities that promote involvement, collaboration and engagement. Modelling of best practices using social networks enhances its usage by participants, increases participants confidence as to its implementation and creates a paradigm shift to a more personalized, participatory and collaborative learning and a more…

  11. Dynamic spectrum management: an impact on EW systems

    NASA Astrophysics Data System (ADS)

    Gajewski, P.; Łopatka, J.; Suchanski, M.

    2017-04-01

    Rapid evolution of wireless systems caused an enormous growth of data streams transmitted through the networks and, as a consequence, an accompanying demand concerning spectrum resources (SR). An avoidance of advisable disturbances is one of the main demands in military communications. To solve the interference problems, dynamic spectrum management (DSM) techniques can be used. Two main techniques are possible: centralized Coordinated Dynamic Spectrum Access (CDSA) and distributed Opportunistic Spectrum Access (OSA). CDSA enables the wireless networks planning automation, and systems dynamic reaction to random changes of Radio Environment (RE). For OSA, cognitive radio (CR) is the most promising technology that enables avoidance of interference with the other spectrum users due to CR's transmission parameters adaptation to the current radio situation, according to predefined Radio Policies rules. If DSM techniques are used, the inherent changes in EW systems are also needed. On one hand, new techniques of jamming should be elaborated, on the other hand, the rules and protocols of cooperation between communication network and EW systems should be developed.

  12. A Spectrum Sensing Network for Cognitive PMSE Systems

    NASA Astrophysics Data System (ADS)

    Brendel, Johannes; Riess, Steffen; Stoeckle, Andreas; Rummel, Rafael; Fischer, Georg

    2012-09-01

    This article is about a Spectrum Sensing Network (SSN) which generates an accurate radio environment map (e.g. power over frequency, time, and location) from a given application area. It is intended to be used in combination with cognitive Program Making and Special Events (PMSE) devices (e.g. wireless microphones) to improve their operation reliability. The SSN consists of a distributed network of multiple scanning radio receivers and a central data management and storage unit. The parts of the SSN are presented in detail and the advantages and use cases of such a sensing network structure will be outlined.

  13. 5G: The Convergence of Wireless Communications.

    PubMed

    Chávez-Santiago, Raúl; Szydełko, Michał; Kliks, Adrian; Foukalas, Fotis; Haddad, Yoram; Nolan, Keith E; Kelly, Mark Y; Masonta, Moshe T; Balasingham, Ilangko

    As the rollout of 4G mobile communication networks takes place, representatives of industry and academia have started to look into the technological developments toward the next generation (5G). Several research projects involving key international mobile network operators, infrastructure manufacturers, and academic institutions, have been launched recently to set the technological foundations of 5G. However, the architecture of future 5G systems, their performance, and mobile services to be provided have not been clearly defined. In this paper, we put forth the vision for 5G as the convergence of evolved versions of current cellular networks with other complementary radio access technologies. Therefore, 5G may not be a single radio access interface but rather a "network of networks". Evidently, the seamless integration of a variety of air interfaces, protocols, and frequency bands, requires paradigm shifts in the way networks cooperate and complement each other to deliver data rates of several Gigabits per second with end-to-end latency of a few milliseconds. We provide an overview of the key radio technologies that will play a key role in the realization of this vision for the next generation of mobile communication networks. We also introduce some of the research challenges that need to be addressed.

  14. Applications of software-defined radio (SDR) technology in hospital environments.

    PubMed

    Chávez-Santiago, Raúl; Mateska, Aleksandra; Chomu, Konstantin; Gavrilovska, Liljana; Balasingham, Ilangko

    2013-01-01

    A software-defined radio (SDR) is a radio communication system where the major part of its functionality is implemented by means of software in a personal computer or embedded system. Such a design paradigm has the major advantage of producing devices that can receive and transmit widely different radio protocols based solely on the software used. This flexibility opens several application opportunities in hospital environments, where a large number of wired and wireless electronic devices must coexist in confined areas like operating rooms and intensive care units. This paper outlines some possible applications in the 2360-2500 MHz frequency band. These applications include the integration of wireless medical devices in a common communication platform for seamless interoperability, and cognitive radio (CR) for body area networks (BANs) and wireless sensor networks (WSNs) for medical environmental surveillance. The description of a proof-of-concept CR prototype is also presented.

  15. Empirical study on dyad act-degree distribution in some collaboration networks

    NASA Astrophysics Data System (ADS)

    Chang, Hui; Zhang, Pei-Pei; He, Yue; He, Da-Ren

    2006-03-01

    We (and cooperators) suggest studying the evolution of the extended collaboration networks by a dyad-act organizing model. The analytic and numeric studies of the model lead to a conclusion that most of the collaboration networks should show a dyad act-degree distribution (how many acts a dyad belongs to) between a power law and an exponential function, which can be described by a shifted power law. We have done an empirical study on dyad act-degree distribution in some collaboration networks. They are: the train networks in China, the bus network of Beijing, and traditional Chinese medical prescription formulation network. The results show good agreement with this conclusion. We also discuss what dyad act-degree implies in these networks and what are the possible applications of the study. The details will be published elsewhere.

  16. Deep Space Telecommunications

    NASA Technical Reports Server (NTRS)

    Kuiper, T. B. H.; Resch, G. M.

    2000-01-01

    The increasing load on NASA's deep Space Network, the new capabilities for deep space missions inherent in a next-generation radio telescope, and the potential of new telescope technology for reducing construction and operation costs suggest a natural marriage between radio astronomy and deep space telecommunications in developing advanced radio telescope concepts.

  17. Metsahovi Radio Observatory - IVS Network Station

    NASA Technical Reports Server (NTRS)

    Uunila, Minttu; Zubko, Nataliya; Poutanen, Markku; Kallunki, Juha; Kallio, Ulla

    2013-01-01

    In 2012, Metsahovi Radio Observatory together with Finnish Geodetic Institute officially became an IVS Network Station. Eight IVS sessions were observed during the year. Two spacecraft tracking and one EVN X-band experiment were also performed. In 2012, the Metsahovi VLBI equipment was upgraded with a Digital Base Band Converter, a Mark 5B+, a FILA10G, and a FlexBuff.

  18. Cable Television: End of a Dream. The Network Project Notebook Number Eight.

    ERIC Educational Resources Information Center

    Columbia Univ., New York, NY. Network Project.

    The Notebook is divided into two parts. The first half reprints the transcript of a radio documentary on cable television, one in a series of five MATRIX radio programs produced by the Network Project in 1974. It includes discussions of planning for the new technology and of its present control by corporate conglomerates, and forecasts a…

  19. Future Technology Themes: 2030 to 2060

    DTIC Science & Technology

    2013-07-01

    Rocket-Based Combined Cycle RF Radio Frequency RNA Ribonucleic Acid SA Situational Awareness SEAD Suppression of Enemy Air Defences SME...and re-routing light in information processing and optical communications ; or for processing radio signals in mobile phones [44]. UNCLASSIFIED DSTO...make use of network polymorphism technologies from 2020 onwards to create frequency -agile and adaptive14 communications links that would change network

  20. Cognitive Radio Cloud Networks: Assured Access In The Future Electromagnetic Operating Environment

    DTIC Science & Technology

    2017-04-04

    AIR COMMAND AND STAFF COLLEGE AIR UNIVERSITY COGNITIVE RADIO CLOUD NETWORKS: ASSURED ACCESS IN THE FUTURE ELECTROMAGNETIC OPERATING...3 Abstract The electromagnetic spectrum is a finite resource that is critical to the United States military’s...ability to gain superiority in the other five warfighting domains. The Department of Defense’s electromagnetic strategy is spectrum access when and

  1. Dynamic Spectrum Access for Internet of Things Service in Cognitive Radio-Enabled LPWANs

    PubMed Central

    Moon, Bongkyo

    2017-01-01

    In this paper, we focus on a dynamic spectrum access strategy for Internet of Things (IoT) applications in two types of radio systems: cellular networks and cognitive radio-enabled low power wide area networks (CR-LPWANs). The spectrum channel contention between the licensed cellular networks and the unlicensed CR-LPWANs, which work with them, only takes place within the cellular radio spectrum range. Our aim is to maximize the spectrum capacity for the unlicensed users while ensuring that it never interferes with the licensed network. Therefore, in this paper we propose a dynamic spectrum access strategy for CR-LPWANs operating in both licensed and unlicensed bands. The simulation and the numerical analysis by using a matrix geometric approach for the strategy are presented. Finally, we obtain the blocking probability of the licensed users, the mean dwell time of the unlicensed user, and the total carried traffic and combined service quality for the licensed and unlicensed users. The results show that the proposed strategy can maximize the spectrum capacity for the unlicensed users using IoT applications as well as keep the service quality of the licensed users independent of them. PMID:29206215

  2. Dynamic Spectrum Access for Internet of Things Service in Cognitive Radio-Enabled LPWANs.

    PubMed

    Moon, Bongkyo

    2017-12-05

    In this paper, we focus on a dynamic spectrum access strategy for Internet of Things (IoT) applications in two types of radio systems: cellular networks and cognitive radio-enabled low power wide area networks (CR-LPWANs). The spectrum channel contention between the licensed cellular networks and the unlicensed CR-LPWANs, which work with them, only takes place within the cellular radio spectrum range. Our aim is to maximize the spectrum capacity for the unlicensed users while ensuring that it never interferes with the licensed network. Therefore, in this paper we propose a dynamic spectrum access strategy for CR-LPWANs operating in both licensed and unlicensed bands. The simulation and the numerical analysis by using a matrix geometric approach for the strategy are presented. Finally, we obtain the blocking probability of the licensed users, the mean dwell time of the unlicensed user, and the total carried traffic and combined service quality for the licensed and unlicensed users. The results show that the proposed strategy can maximize the spectrum capacity for the unlicensed users using IoT applications as well as keep the service quality of the licensed users independent of them.

  3. Properties of four real world collaboration--competition networks

    NASA Astrophysics Data System (ADS)

    Fu, Chun-Hua; Xu, Xiu-Lian; He, Da-Ren

    2009-03-01

    Our research group has empirically investigated 9 real world collaboration networks and 25 real world cooperation-competition networks. Among the 34 real world systems, all the 9 real world collaboration networks and 6 real world cooperation-competition networks show the unimodal act-size distribution and the shifted power law distribution of degree and act-degree. We have proposed a collaboration network evolution model for an explanation of the rules [1]. The other 14 real world cooperation-competition networks show that the act-size distributions are not unimodal; instead, they take qualitatively the same shifted power law forms as the degree and act-degree distributions. The properties of four systems (the main land movie film network, Beijing restaurant network, 2004 Olympic network, and Tao-Bao notebook computer sale network) are reported in detail as examples. Via a numerical simulation, we show that the new rule can still be explained by the above-mentioned model. [1] H. Chang, B. B. Su, et al. Phsica A, 2007, 383: 687-702.

  4. The Telecommunications and Data Acquisition

    NASA Technical Reports Server (NTRS)

    Renzetti, N. A. (Editor)

    1981-01-01

    Progress in the development and operations of the Deep Space Network is reported including developments in Earth based radio technology as applied to other research programs. These programs include application of radio interferometry at microwave frequencies to geodetic measurements and geodynamics, use of deep space stations individually and in pairs as an interferometer by radio astronomers for astrophysics research by direct observations of radio sources, and radio search for extraterrestrial intelligence in the microwave region of the electromagnetic spectrum.

  5. The Telecommunications and Data Acquisition Report

    NASA Technical Reports Server (NTRS)

    Yuen, Joseph H. (Editor)

    1993-01-01

    This quarterly publication provides archival reports on developments in programs managed by JPL's Office of Telecommunications and Data Acquisition (TDA). In space communications, radio navigation, radio science, and ground-based radio and radar astronomy, it reports on activities of the Deep Space Network (DSN) in planning, supporting research and technology, implementation, and operations. Also included are standards activity at JPL for space data and information systems and reimbursable DSN work performed for other space agencies through NASA. The papers included in this document cover satellite tracking and ground-based navigation, spacecraft-ground communications, and optical communication systems for the Deep Space Network.

  6. Software-defined Radio Based Measurement Platform for Wireless Networks

    PubMed Central

    Chao, I-Chun; Lee, Kang B.; Candell, Richard; Proctor, Frederick; Shen, Chien-Chung; Lin, Shinn-Yan

    2015-01-01

    End-to-end latency is critical to many distributed applications and services that are based on computer networks. There has been a dramatic push to adopt wireless networking technologies and protocols (such as WiFi, ZigBee, WirelessHART, Bluetooth, ISA100.11a, etc.) into time-critical applications. Examples of such applications include industrial automation, telecommunications, power utility, and financial services. While performance measurement of wired networks has been extensively studied, measuring and quantifying the performance of wireless networks face new challenges and demand different approaches and techniques. In this paper, we describe the design of a measurement platform based on the technologies of software-defined radio (SDR) and IEEE 1588 Precision Time Protocol (PTP) for evaluating the performance of wireless networks. PMID:27891210

  7. Software-defined Radio Based Measurement Platform for Wireless Networks.

    PubMed

    Chao, I-Chun; Lee, Kang B; Candell, Richard; Proctor, Frederick; Shen, Chien-Chung; Lin, Shinn-Yan

    2015-10-01

    End-to-end latency is critical to many distributed applications and services that are based on computer networks. There has been a dramatic push to adopt wireless networking technologies and protocols (such as WiFi, ZigBee, WirelessHART, Bluetooth, ISA100.11a, etc. ) into time-critical applications. Examples of such applications include industrial automation, telecommunications, power utility, and financial services. While performance measurement of wired networks has been extensively studied, measuring and quantifying the performance of wireless networks face new challenges and demand different approaches and techniques. In this paper, we describe the design of a measurement platform based on the technologies of software-defined radio (SDR) and IEEE 1588 Precision Time Protocol (PTP) for evaluating the performance of wireless networks.

  8. Fronthaul evolution: From CPRI to Ethernet

    NASA Astrophysics Data System (ADS)

    Gomes, Nathan J.; Chanclou, Philippe; Turnbull, Peter; Magee, Anthony; Jungnickel, Volker

    2015-12-01

    It is proposed that using Ethernet in the fronthaul, between base station baseband unit (BBU) pools and remote radio heads (RRHs), can bring a number of advantages, from use of lower-cost equipment, shared use of infrastructure with fixed access networks, to obtaining statistical multiplexing and optimised performance through probe-based monitoring and software-defined networking. However, a number of challenges exist: ultra-high-bit-rate requirements from the transport of increased bandwidth radio streams for multiple antennas in future mobile networks, and low latency and jitter to meet delay requirements and the demands of joint processing. A new fronthaul functional division is proposed which can alleviate the most demanding bit-rate requirements by transport of baseband signals instead of sampled radio waveforms, and enable statistical multiplexing gains. Delay and synchronisation issues remain to be solved.

  9. Building international collaborative capacity: contributions of community psychologists to a European network.

    PubMed

    García-Ramírez, Manuel; Paloma, Virginia; Suarez-Balcazar, Yolanda; Balcazar, Fabricio

    2009-09-01

    Europe is in the process of building a more participative, just, and inclusive European Union. The European Social Fund, which is an initiative developed to actively promote multinational partnerships that address pressing social issues, is a good example of the European transformation. This article describes the steps taken to develop and evaluate the activities of an international network promoting collaborative capacity among regional partners involved in the prevention of labor discrimination toward immigrants in three European countries-Spain, Belgium, and Italy. An international team of community psychologists proposed an empowering approach to assess the collaborative capacity of the network. This approach consisted of three steps: (1) establishing a collaborative relationship among partners, (2) building collaborative capacity, and (3) evaluating the collaborative capacity of the network. We conclude with lessons learned from the process and provide recommendations for addressing the challenges inherent in international collaboration processes.

  10. Radio detection of SN 2006jd with the VLA

    NASA Astrophysics Data System (ADS)

    Chandra, Poonam; Soderberg, Alicia

    2007-11-01

    Poonam Chandra and Alicia Soderberg report on behalf of a larger collaboration: We observed Type IIn supernova SN 2006jd (CBET 673), recently shown to be very bright in X-rays (ATel 1290), with the VLA in 8.46 GHz band on 2007, November 21.28 UT. We detect radio emission at the SN position (IAUC 8762) with the flux density of 238 +/- 40 uJy.

  11. Software Defined Radio Architecture Contributions to Next Generation Space Communications

    NASA Technical Reports Server (NTRS)

    Kacpura, Thomas J.; Eddy, Wesley M.; Smith, Carl R.; Liebetreu, John

    2015-01-01

    Space communications architecture concepts, comprising the elements of the system, the interactions among them, and the principles that govern their development, are essential factors in developing National Aeronautics and Space Administration (NASA) future exploration and science missions. Accordingly, vital architectural attributes encompass flexibility, the extensibility to insert future capabilities, and to enable evolution to provide interoperability with other current and future systems. Space communications architectures and technologies for this century must satisfy a growing set of requirements, including those for Earth sensing, collaborative observation missions, robotic scientific missions, human missions for exploration of the Moon and Mars where surface activities require supporting communications, and in-space observatories for observing the earth, as well as other star systems and the universe. An advanced, integrated, communications infrastructure will enable the reliable, multipoint, high-data-rate capabilities needed on demand to provide continuous, maximum coverage for areas of concentrated activity. Importantly, the cost/value proposition of the future architecture must be an integral part of its design; an affordable and sustainable architecture is indispensable within anticipated future budget environments. Effective architecture design informs decision makers with insight into the capabilities needed to efficiently satisfy the demanding space-communication requirements of future missions and formulate appropriate requirements. A driving requirement for the architecture is the extensibility to address new requirements and provide low-cost on-ramps for new capabilities insertion, ensuring graceful growth as new functionality and new technologies are infused into the network infrastructure. In addition to extensibility, another key architectural attribute of the space communication equipment's interoperability with other NASA communications systems, as well as those communications and navigation systems operated by international space agencies and civilian and government agencies. In this paper, we review the philosophies, technologies, architectural attributes, mission services, and communications capabilities that form the structure of candidate next-generation integrated communication architectures for space communications and navigation. A key area that this paper explores is from the development and operation of the software defined radio for the NASA Space Communications and Navigation (SCaN) Testbed currently on the International Space Station (ISS). Evaluating the lessons learned from development and operation feed back into the communications architecture. Leveraging the reconfigurability provides a change in the way that operations are done and must be considered. Quantifying the impact on the NASA Space Telecommunications Radio System (STRS) software defined radio architecture provides feedback to keep the standard useful and up to date. NASA is not the only customer of these radios. Software defined radios are developed for other applications, and taking advantage of these developments promotes an architecture that is cost effective and sustainable. Developments in the following areas such as an updated operating environment, higher data rates, networking and security can be leveraged. The ability to sustain an architecture that uses radios for multiple markets can lower costs and keep new technology infused.

  12. A Study on Cognitive Radio Coexisting with Cellular Systems

    NASA Astrophysics Data System (ADS)

    Tandai, Tomoya; Horiguchi, Tomoya; Deguchi, Noritaka; Tomizawa, Takeshi; Tomioka, Tazuko

    Cognitive Radios (CRs) are expected to perform more significant role in the view of efficient utilization of the spectrum resources in the future wireless communication networks. In this paper, a cognitive radio coexisting with cellular systems is proposed. In the case that a cellular system adopts Frequency Division Duplex (FDD) as a multiplexing scheme, the proposed CR terminals communicate in local area on uplink channels of the cellular system with transmission powers that don't interfere with base stations of the cellular system. Alternatively, in the case that a cellular system adopts Time Division Duplex (TDD), the CR terminals communicate on uplink slots of the cellular system. However if mobile terminals in the cellular system are near the CR network, uplink signals from the mobile terminals may interfere with the CR communications. In order to avoid interference from the mobile terminals, the CR terminal performs carrier sense during a beginning part of uplink slot, and only when the level of detected signal is below a threshold, then the CR terminal transmits a signal during the remained period of the uplink slot. In this paper, both the single carrier CR network that uses one frequency channel of the cellular system and the multicarrier CR network that uses multiple frequency channels of the cellular system are considered. The probabilities of successful CR communications, the average throughputs of the CR communications according to the positions of the CR network, and the interference levels from cognitive radio network to base stations of the cellular system are evaluated in the computer simulation then the effectiveness of the proposed network is clarified.

  13. Programming an Artificial Neural Network Tool for Spatial Interpolation in GIS - A Case Study for Indoor Radio Wave Propagation of WLAN.

    PubMed

    Sen, Alper; Gümüsay, M Umit; Kavas, Aktül; Bulucu, Umut

    2008-09-25

    Wireless communication networks offer subscribers the possibilities of free mobility and access to information anywhere at any time. Therefore, electromagnetic coverage calculations are important for wireless mobile communication systems, especially in Wireless Local Area Networks (WLANs). Before any propagation computation is performed, modeling of indoor radio wave propagation needs accurate geographical information in order to avoid the interruption of data transmissions. Geographic Information Systems (GIS) and spatial interpolation techniques are very efficient for performing indoor radio wave propagation modeling. This paper describes the spatial interpolation of electromagnetic field measurements using a feed-forward back-propagation neural network programmed as a tool in GIS. The accuracy of Artificial Neural Networks (ANN) and geostatistical Kriging were compared by adjusting procedures. The feedforward back-propagation ANN provides adequate accuracy for spatial interpolation, but the predictions of Kriging interpolation are more accurate than the selected ANN. The proposed GIS ensures indoor radio wave propagation model and electromagnetic coverage, the number, position and transmitter power of access points and electromagnetic radiation level. Pollution analysis in a given propagation environment was done and it was demonstrated that WLAN (2.4 GHz) electromagnetic coverage does not lead to any electromagnetic pollution due to the low power levels used. Example interpolated electromagnetic field values for WLAN system in a building of Yildiz Technical University, Turkey, were generated using the selected network architectures to illustrate the results with an ANN.

  14. Programming an Artificial Neural Network Tool for Spatial Interpolation in GIS - A Case Study for Indoor Radio Wave Propagation of WLAN

    PubMed Central

    Şen, Alper; Gümüşay, M. Ümit; Kavas, Aktül; Bulucu, Umut

    2008-01-01

    Wireless communication networks offer subscribers the possibilities of free mobility and access to information anywhere at any time. Therefore, electromagnetic coverage calculations are important for wireless mobile communication systems, especially in Wireless Local Area Networks (WLANs). Before any propagation computation is performed, modeling of indoor radio wave propagation needs accurate geographical information in order to avoid the interruption of data transmissions. Geographic Information Systems (GIS) and spatial interpolation techniques are very efficient for performing indoor radio wave propagation modeling. This paper describes the spatial interpolation of electromagnetic field measurements using a feed-forward back-propagation neural network programmed as a tool in GIS. The accuracy of Artificial Neural Networks (ANN) and geostatistical Kriging were compared by adjusting procedures. The feedforward back-propagation ANN provides adequate accuracy for spatial interpolation, but the predictions of Kriging interpolation are more accurate than the selected ANN. The proposed GIS ensures indoor radio wave propagation model and electromagnetic coverage, the number, position and transmitter power of access points and electromagnetic radiation level. Pollution analysis in a given propagation environment was done and it was demonstrated that WLAN (2.4 GHz) electromagnetic coverage does not lead to any electromagnetic pollution due to the low power levels used. Example interpolated electromagnetic field values for WLAN system in a building of Yildiz Technical University, Turkey, were generated using the selected network architectures to illustrate the results with an ANN. PMID:27873854

  15. NOAA Weather Radio

    Science.gov Websites

    Questions NOAA WEATHER RADIO Marine Coverage The NOAA Weather Radio network provides near continuous coverage of the coastal U.S, Great Lakes, Hawaii, and populated Alaska coastline. Typical coverage is 25 Transmitter frequency, call sign and power; and remarks (if any.) Atlantic Gulf of Mexico Great Lakes West

  16. Continuing Development of California State Packet Radio Project.

    ERIC Educational Resources Information Center

    Brownrigg, Edwin

    1992-01-01

    Provides background on the California State Library Packet Radio project, which will use packet radios to deploy a wireless, high-speed, wide-area network of 600 nodes, including 100 libraries, in the San Francisco Bay Area. Project goals and objectives, plan of operation, equipment, and evaluation plans are summarized. (MES)

  17. The telecommunications and data acquisition report

    NASA Technical Reports Server (NTRS)

    1980-01-01

    Progress in the development and operations of the Deep Space Network is reported. Developments in Earth based radio technology as applied to geodynamics, astrophysics, and radio astronomy's use of the deep space stations for a radio search for extraterrestrial intelligence in the microwave region of the electromagnetic spectrum are reported.

  18. Analysis of radio wave propagation for ISM 2.4 GHz Wireless Sensor Networks in inhomogeneous vegetation environments.

    PubMed

    Azpilicueta, Leire; López-Iturri, Peio; Aguirre, Erik; Mateo, Ignacio; Astrain, José Javier; Villadangos, Jesús; Falcone, Francisco

    2014-12-10

    The use of wireless networks has experienced exponential growth due to the improvements in terms of battery life and low consumption of the devices. However, it is compulsory to conduct previous radio propagation analysis when deploying a wireless sensor network. These studies are necessary to perform an estimation of the range coverage, in order to optimize the distance between devices in an actual network deployment. In this work, the radio channel characterization for ISM 2.4 GHz Wireless Sensor Networks (WSNs) in an inhomogeneous vegetation environment has been analyzed. This analysis allows designing environment monitoring tools based on ZigBee and WiFi where WSN and smartphones cooperate, providing rich and customized monitoring information to users in a friendly manner. The impact of topology as well as morphology of the environment is assessed by means of an in-house developed 3D Ray Launching code, to emulate the realistic operation in the framework of the scenario. Experimental results gathered from a measurement campaign conducted by deploying a ZigBee Wireless Sensor Network, are analyzed and compared with simulations in this paper. The scenario where this network is intended to operate is a combination of buildings and diverse vegetation species. To gain insight in the effects of radio propagation, a simplified vegetation model has been developed, considering the material parameters and simplified geometry embedded in the simulation scenario. An initial location-based application has been implemented in a real scenario, to test the functionality within a context aware scenario. The use of deterministic tools can aid to know the impact of the topological influence in the deployment of the optimal Wireless Sensor Network in terms of capacity, coverage and energy consumption, making the use of these systems attractive for multiple applications in inhomogeneous vegetation environments.

  19. Optimization-based channel constrained data aggregation routing algorithms in multi-radio wireless sensor networks.

    PubMed

    Yen, Hong-Hsu

    2009-01-01

    In wireless sensor networks, data aggregation routing could reduce the number of data transmissions so as to achieve energy efficient transmission. However, data aggregation introduces data retransmission that is caused by co-channel interference from neighboring sensor nodes. This kind of co-channel interference could result in extra energy consumption and significant latency from retransmission. This will jeopardize the benefits of data aggregation. One possible solution to circumvent data retransmission caused by co-channel interference is to assign different channels to every sensor node that is within each other's interference range on the data aggregation tree. By associating each radio with a different channel, a sensor node could receive data from all the children nodes on the data aggregation tree simultaneously. This could reduce the latency from the data source nodes back to the sink so as to meet the user's delay QoS. Since the number of radios on each sensor node and the number of non-overlapping channels are all limited resources in wireless sensor networks, a challenging question here is to minimize the total transmission cost under limited number of non-overlapping channels in multi-radio wireless sensor networks. This channel constrained data aggregation routing problem in multi-radio wireless sensor networks is an NP-hard problem. I first model this problem as a mixed integer and linear programming problem where the objective is to minimize the total transmission subject to the data aggregation routing, channel and radio resources constraints. The solution approach is based on the Lagrangean relaxation technique to relax some constraints into the objective function and then to derive a set of independent subproblems. By optimally solving these subproblems, it can not only calculate the lower bound of the original primal problem but also provide useful information to get the primal feasible solutions. By incorporating these Lagrangean multipliers as the link arc weight, the optimization-based heuristics are proposed to get energy-efficient data aggregation tree with better resource (channel and radio) utilization. From the computational experiments, the proposed optimization-based approach is superior to existing heuristics under all tested cases.

  20. GLOBECOM '88 - IEEE Global Telecommunications Conference and Exhibition, Hollywood, FL, Nov. 28-Dec. 1, 1988, Conference Record. Volumes 1, 2, & 3

    NASA Astrophysics Data System (ADS)

    Various papers on communications for the information age are presented. Among the general topics considered are: telematic services and terminals, satellite communications, telecommunications mangaement network, control of integrated broadband networks, advances in digital radio systems, the intelligent network, broadband networks and services deployment, future switch architectures, performance analysis of computer networks, advances in spread spectrum, optical high-speed LANs, and broadband switching and networks. Also addressed are: multiple access protocols, video coding techniques, modulation and coding, photonic switching, SONET terminals and applications, standards for video coding, digital switching, progress in MANs, mobile and portable radio, software design for improved maintainability, multipath propagation and advanced countermeasure, data communication, network control and management, fiber in the loop, network algorithm and protocols, and advances in computer communications.

  1. Network Effects on Scientific Collaborations

    PubMed Central

    Uddin, Shahadat; Hossain, Liaquat; Rasmussen, Kim

    2013-01-01

    Background The analysis of co-authorship network aims at exploring the impact of network structure on the outcome of scientific collaborations and research publications. However, little is known about what network properties are associated with authors who have increased number of joint publications and are being cited highly. Methodology/Principal Findings Measures of social network analysis, for example network centrality and tie strength, have been utilized extensively in current co-authorship literature to explore different behavioural patterns of co-authorship networks. Using three SNA measures (i.e., degree centrality, closeness centrality and betweenness centrality), we explore scientific collaboration networks to understand factors influencing performance (i.e., citation count) and formation (tie strength between authors) of such networks. A citation count is the number of times an article is cited by other articles. We use co-authorship dataset of the research field of ‘steel structure’ for the year 2005 to 2009. To measure the strength of scientific collaboration between two authors, we consider the number of articles co-authored by them. In this study, we examine how citation count of a scientific publication is influenced by different centrality measures of its co-author(s) in a co-authorship network. We further analyze the impact of the network positions of authors on the strength of their scientific collaborations. We use both correlation and regression methods for data analysis leading to statistical validation. We identify that citation count of a research article is positively correlated with the degree centrality and betweenness centrality values of its co-author(s). Also, we reveal that degree centrality and betweenness centrality values of authors in a co-authorship network are positively correlated with the strength of their scientific collaborations. Conclusions/Significance Authors’ network positions in co-authorship networks influence the performance (i.e., citation count) and formation (i.e., tie strength) of scientific collaborations. PMID:23469021

  2. Near Earth Network (NEN) CubeSat Communications

    NASA Technical Reports Server (NTRS)

    Schaire, Scott

    2017-01-01

    The NASA Near Earth Network (NEN) consists of globally distributed tracking stations, including NASA, commercial, and partner ground stations, that are strategically located to maximize the coverage provided to a variety of orbital and suborbital missions, including those in LEO (Low Earth Orbit), GEO (Geosynchronous Earth Orbit), HEO (Highly Elliptical Orbit), lunar and L1-L2 orbits. The NEN's future mission set includes and will continue to include CubeSat missions. The first NEN-supported CubeSat mission will be the Cubesat Proximity Operations Demonstration (CPOD) launching into LEO in 2017. The majority of the CubeSat missions destined to fly on EM-1, launching in late 2018, many in a lunar orbit, will communicate with ground-based stations via X-band and will utilize the NASA Jet Propulsion Laboratory (JPL)-developed IRIS (Satellite Communication for Air Traffic Management) radio. The NEN recognizes the important role CubeSats are beginning to play in carrying out NASAs mission and is therefore investigating the modifications needed to provide IRIS radio compatibility. With modification, the NEN could potentially expand support to the EM-1 (Exploration Mission-1) lunar CubeSats. The NEN could begin providing significant coverage to lunar CubeSat missions utilizing three to four of the NEN's mid-latitude sites. This coverage would supplement coverage provided by the JPL Deep Space Network (DSN). The NEN, with smaller apertures than DSN, provides the benefit of a larger beamwidth that could be beneficial in the event of uncertain ephemeris data. In order to realize these benefits the NEN would need to upgrade stations targeted based on coverage ability and current configuration ease of upgrade, to ensure compatibility with the IRIS radio. In addition, the NEN is working with CubeSat radio developers to ensure NEN compatibility with alternative CubeSat radios for Lunar and L1-L2 CubeSats. The NEN has provided NEN compatibility requirements to several radio developers who are developing radios that offer lower cost and, in some cases, more capabilities with fewer constraints. The NEN is ready to begin supporting CubeSat missions. The NEN is considering network upgrades to broaden the types of CubeSat missions that can be supported and is supporting both the CubeSat community and radio developers to ensure future CubeSat missions have multiple options when choosing a network for their communications support.

  3. NASA Near Earth Network (NEN) Support for Lunar and L1/L2 CubeSats

    NASA Technical Reports Server (NTRS)

    Schaire, Scott H.

    2017-01-01

    The NASA Near Earth Network (NEN) consists of globally distributed tracking stations, including NASA, commercial, and partner ground stations, that are strategically located to maximize the coverage provided to a variety of orbital and suborbital missions, including those in LEO, GEO, HEO, lunar and L1/L2 orbits. The NENs future mission set includes and will continue to include CubeSat missions. The first NEN supported CubeSat mission will be the Cubesat Proximity Operations Demonstration (CPOD) launching into low earth orbit (LEO) in early 2017. The majority of the CubeSat missions destined to fly on EM-1, launching in late 2018, many in a lunar orbit, will communicate with ground based stations via X-band and will utilize the NASA Jet Propulsion Laboratory (JPL) developed IRIS radio. The NEN recognizes the important role CubeSats are beginning to play in carrying out NASAs mission and is therefore investigating the modifications needed to provide IRIS radio compatibility. With modification, the NEN could potentially expand support to the EM-1 lunar CubeSats. The NEN could begin providing significant coverage to lunar CubeSat missions utilizing three to four of the NENs mid-latitude sites. This coverage would supplement coverage provided by the JPL Deep Space Network (DSN). The NEN, with smaller apertures than DSN, provides the benefit of a larger beamwidth that could be beneficial in the event of uncertain ephemeris data. In order to realize these benefits the NEN would need to upgrade stations targeted based on coverage ability and current configurationease of upgrade, to ensure compatibility with the IRIS radio.In addition, the NEN is working with CubeSat radio developers to ensure NEN compatibility with alternative CubeSat radios for Lunar and L1/L2 CubeSats. The NEN has provided NEN compatibility requirements to several radio developers who are developing radios that offer lower cost and, in some cases, more capabilities with fewer constraints. The NEN is ready to begin supporting CubeSat missions. The NEN is considering network upgrades to broaden the types of CubeSat missions that can be supported and is supporting both the CubeSat community and radio developers to ensure future CubeSat missions have multiple options when choosing a network for their communications support.

  4. Assessing Collaboration Networks in Educational Research: A Co-Authorship-Based Social Network Analysis Approach

    ERIC Educational Resources Information Center

    Munoz, David Andres; Queupil, Juan Pablo; Fraser, Pablo

    2016-01-01

    Purpose: The purpose of this paper is to analyze collaboration networks and their patterns among higher education institutions (HEIs) in Chile and the Latin American region. This will provide evidence to educational managements in order to properly allocate their efforts to improve collaboration. Design/methodology/approach: This quantitative…

  5. Collaborative Network Management for Enhancing Quality Education of Primary Schools

    ERIC Educational Resources Information Center

    Chaikoed, Wisithsak; Sirisuthi, Chaiyuth; Numnaphol, Kochaporn

    2017-01-01

    This research aims to study the network and collaborative factors that enhance quality education of primary schools. Different methods were used in this research work: (1) Related approaches, theories, and research literatures and (2) Scholars were interviewed on 871 issues in the form of questionnaire, and the collaborative network factors were…

  6. 76 FR 38124 - Applications for New Awards; Americans With Disabilities Act (ADA) National Network Regional...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-06-29

    ...) National Network Regional Centers and ADA National Network Collaborative Research Projects AGENCY: Office... National Network Regional Centers (formerly the Disability Business Technical Assistance Centers (DBTACs), and ADA National Network Collaborative Research Projects. Notice inviting applications for new awards...

  7. Analysis of inter-country input-output table based on citation network: How to measure the competition and collaboration between industrial sectors on the global value chain

    PubMed Central

    2017-01-01

    The input-output table is comprehensive and detailed in describing the national economic system with complex economic relationships, which embodies information of supply and demand among industrial sectors. This paper aims to scale the degree of competition/collaboration on the global value chain from the perspective of econophysics. Global Industrial Strongest Relevant Network models were established by extracting the strongest and most immediate industrial relevance in the global economic system with inter-country input-output tables and then transformed into Global Industrial Resource Competition Network/Global Industrial Production Collaboration Network models embodying the competitive/collaborative relationships based on bibliographic coupling/co-citation approach. Three indicators well suited for these two kinds of weighted and non-directed networks with self-loops were introduced, including unit weight for competitive/collaborative power, disparity in the weight for competitive/collaborative amplitude and weighted clustering coefficient for competitive/collaborative intensity. Finally, these models and indicators were further applied to empirically analyze the function of sectors in the latest World Input-Output Database, to reveal inter-sector competitive/collaborative status during the economic globalization. PMID:28873432

  8. Analysis of inter-country input-output table based on citation network: How to measure the competition and collaboration between industrial sectors on the global value chain.

    PubMed

    Xing, Lizhi

    2017-01-01

    The input-output table is comprehensive and detailed in describing the national economic system with complex economic relationships, which embodies information of supply and demand among industrial sectors. This paper aims to scale the degree of competition/collaboration on the global value chain from the perspective of econophysics. Global Industrial Strongest Relevant Network models were established by extracting the strongest and most immediate industrial relevance in the global economic system with inter-country input-output tables and then transformed into Global Industrial Resource Competition Network/Global Industrial Production Collaboration Network models embodying the competitive/collaborative relationships based on bibliographic coupling/co-citation approach. Three indicators well suited for these two kinds of weighted and non-directed networks with self-loops were introduced, including unit weight for competitive/collaborative power, disparity in the weight for competitive/collaborative amplitude and weighted clustering coefficient for competitive/collaborative intensity. Finally, these models and indicators were further applied to empirically analyze the function of sectors in the latest World Input-Output Database, to reveal inter-sector competitive/collaborative status during the economic globalization.

  9. Organizational collaborative capacity in fighting pandemic crises: a literature review from the public management perspective.

    PubMed

    Lai, Allen Y

    2012-01-01

    Collaborative capacity serves for organizations as the capacity to collaborate with other network players. Organizational capacity matters as collaboration outcomes usually go beyond single-shot implementation efforts or a single-minded focus on either the vertical dimension of program or the horizontal component. This review article explores organizational collaborative capacities from the perspective of public management, in particular, network theory. By applying the 5 attributes of network theory-interdependence, membership, resources, information, and learning-to the explanation of collaborative capacity in fighting pandemic crises, I argue in some ways organizational collaborative capacity is very much like an organization in its own right. Studying collaborative capacity in the battle against pandemics facilitate our understanding of multisectoral collaboration in technical, political, and institutional dimensions, and greatly advances the richness of capacity vocabulary in pandemic response and preparedness.

  10. Proposed Construction of Boulder Seismic Station Monitoring Sites, Boulder, Wyoming. Environmental Assessment

    DTIC Science & Technology

    2009-02-01

    power battery box and controllers, WiFi radio, network switch, vault seismometers, infrasonic digitizers, and excess cabling. In addition to the...installed around the boreholes. Immediately upon completion, each site will be cleared of all unused equipment, debris, materials, and trash . All...controllers, WiFi radio, network switch, vault seismometers, infrasonic digitizers, and excess cabling. In addition to the permanent infrastructure listed

  11. Telecommunications media for the delivery of educational programming

    NASA Technical Reports Server (NTRS)

    Ballard, R.; Eastwood, L. F., Jr.

    1974-01-01

    The technical characteristics of various telecommunications media are examined for incorporation into educational networks. FM radio, AM radio, and VHF and UHF television are considered along with computer-aided instruction. The application of iteration networks to library systems, and microform technology are discussed. The basic principles of the communications theory are outlined, and the operation of the PLATO 4 random access system is described.

  12. Receiver Statistics for Cognitive Radios in Dynamic Spectrum Access Networks

    DTIC Science & Technology

    2012-02-28

    SNR) are employed by many protocols and processes in direct-sequence ( DS ) spread-spectrum packet radio networks, including soft-decision decoding...adaptive modulation protocols, and power adjustment protocols. For DS spread spectrum, we have introduced and evaluated SNR estimators that employ...obtained during demodulation in a binary CDMA receiver. We investigated several methods to apply the proposed metric to the demodulator’s soft-decision

  13. Design of a Threat-Based Gunnery Performance Test: Issues and Procedures for Crew and Platoon Tank Gunnery

    DTIC Science & Technology

    1990-06-01

    Uses visual communication . _._Changes direction/formation __Crews transmit timely, accurate quickly. messages. NOTES. Figure 22. Sample engagement...and concise. The network control station (NCS) effectively maintains network discipline. Radio security equipment, visual communication , wire...net discipline, (c) clarity and brevity of radio messages, (d) use of transmission security equipment, (e) use of visual communication , (f) use of wire

  14. Latin America Report.

    DTIC Science & Technology

    1986-10-30

    Decision To Confiscate Cattle (Brasilia Radio Nacional da Amazonia Network, 10 Oct 86). 31 Briefs Area Sugar Exporters’ Meeting 32 Funaro Supports...86) 85 Magazine Editor on Response to Summer Editorial Changes (BOHEMIA, No 35, 29 Aug 86) DOMINICAN REPUBLIC /12223 89 Produce Supply...PY101303 Brasilia Radio Nacional da Amazonia Network in Portuguese 1000 GMT 10 Oct 86 [Excerpts] The government has confiscated 2,000 head of cattle

  15. Electronic collaboration in dermatology resident training through social networking.

    PubMed

    Meeks, Natalie M; McGuire, April L; Carroll, Bryan T

    2017-04-01

    The use of online educational resources and professional social networking sites is increasing. The field of dermatology is currently under-utilizing online social networking as a means of professional collaboration and sharing of training materials. In this study, we sought to assess the current structure of and satisfaction with dermatology resident education and gauge interest for a professional social networking site for educational collaboration. Two surveys-one for residents and one for faculty-were electronically distributed via the American Society for Dermatologic Surgery and Association of Professors of Dermatology (APD) listserves. The surveys confirmed that there is interest among dermatology residents and faculty in a dermatology professional networking site with the goal to enhance educational collaboration.

  16. Energy-efficient sensing in wireless sensor networks using compressed sensing.

    PubMed

    Razzaque, Mohammad Abdur; Dobson, Simon

    2014-02-12

    Sensing of the application environment is the main purpose of a wireless sensor network. Most existing energy management strategies and compression techniques assume that the sensing operation consumes significantly less energy than radio transmission and reception. This assumption does not hold in a number of practical applications. Sensing energy consumption in these applications may be comparable to, or even greater than, that of the radio. In this work, we support this claim by a quantitative analysis of the main operational energy costs of popular sensors, radios and sensor motes. In light of the importance of sensing level energy costs, especially for power hungry sensors, we consider compressed sensing and distributed compressed sensing as potential approaches to provide energy efficient sensing in wireless sensor networks. Numerical experiments investigating the effectiveness of compressed sensing and distributed compressed sensing using real datasets show their potential for efficient utilization of sensing and overall energy costs in wireless sensor networks. It is shown that, for some applications, compressed sensing and distributed compressed sensing can provide greater energy efficiency than transform coding and model-based adaptive sensing in wireless sensor networks.

  17. Space Telecommunications Radio System STRS Cognitive Radio

    NASA Technical Reports Server (NTRS)

    Briones, Janette C.; Handler, Louis M.

    2013-01-01

    Radios today are evolving from awareness toward cognition. A software defined radio (SDR) provides the most capability for integrating autonomic decision making ability and allows the incremental evolution toward a cognitive radio. This cognitive radio technology will impact NASA space communications in areas such as spectrum utilization, interoperability, network operations, and radio resource management over a wide range of operating conditions. NASAs cognitive radio will build upon the infrastructure being developed by Space Telecommunication Radio System (STRS) SDR technology. This paper explores the feasibility of inserting cognitive capabilities in the NASA STRS architecture and the interfaces between the cognitive engine and the STRS radio. The STRS architecture defines methods that can inform the cognitive engine about the radio environment so that the cognitive engine can learn autonomously from experience, and take appropriate actions to adapt the radio operating characteristics and optimize performance.

  18. Energy-Efficient Cognitive Radio Sensor Networks: Parametric and Convex Transformations

    PubMed Central

    Naeem, Muhammad; Illanko, Kandasamy; Karmokar, Ashok; Anpalagan, Alagan; Jaseemuddin, Muhammad

    2013-01-01

    Designing energy-efficient cognitive radio sensor networks is important to intelligently use battery energy and to maximize the sensor network life. In this paper, the problem of determining the power allocation that maximizes the energy-efficiency of cognitive radio-based wireless sensor networks is formed as a constrained optimization problem, where the objective function is the ratio of network throughput and the network power. The proposed constrained optimization problem belongs to a class of nonlinear fractional programming problems. Charnes-Cooper Transformation is used to transform the nonlinear fractional problem into an equivalent concave optimization problem. The structure of the power allocation policy for the transformed concave problem is found to be of a water-filling type. The problem is also transformed into a parametric form for which a ε-optimal iterative solution exists. The convergence of the iterative algorithms is proven, and numerical solutions are presented. The iterative solutions are compared with the optimal solution obtained from the transformed concave problem, and the effects of different system parameters (interference threshold level, the number of primary users and secondary sensor nodes) on the performance of the proposed algorithms are investigated. PMID:23966194

  19. Who collaborates and why: Assessment and diagnostic of governance network integration for salmon restoration in Puget Sound, USA.

    PubMed

    Sayles, Jesse S; Baggio, Jacopo A

    2017-01-15

    Governance silos are settings in which different organizations work in isolation and avoid sharing information and strategies. Siloes are a fundamental challenge for environmental planning and problem solving, which generally requires collaboration. Siloes can be overcome by creating governance networks. Studying the structure and function of these networks is important for understanding how to create institutional arrangements that can respond to the biophysical dynamics of a specific natural resource system (i.e., social-ecological, or institutional fit). Using the case of salmon restoration in a sub-basin of Puget Sound, USA, we assess network integration, considering three different reasons for network collaborations (i.e., mandated, funded, and shared interest relationships) and analyze how these different collaboration types relate to productivity based on practitioner's assessments. We also illustrate how specific and targeted network interventions might enhance the network. To do so, we use a mixed methods approach that combines quantitative social network analysis (SNA) and qualitative interview analysis. Overall, the sub-basin's governance network is fairly well integrated, but several concerning gaps exist. Funded, mandated, and shared interest relationships lead to different network patterns. Mandated relationships are associated with lower productivity than shared interest relationships, highlighting the benefit of genuine collaboration in collaborative watershed governance. Lastly, quantitative and qualitative data comparisons strengthen recent calls to incorporate geographic space and the role of individual actors versus organizational culture into natural resource governance research using SNA. Copyright © 2016 Elsevier Ltd. All rights reserved.

  20. Collaborative research networks in health: a pragmatic scoping study for the development of an imaging network.

    PubMed

    Robinson, Tracy Elizabeth; Rankin, Nicole; Janssen, Anna; Mcgregor, Deborah; Grieve, Stuart; Shaw, Timothy

    2015-12-09

    Collaborative research networks are often touted as a solution for enhancing the translation of knowledge, but questions remain about how to evaluate their impact on health service delivery. This pragmatic scoping study explored the enabling factors for developing and supporting a collaborative imaging network in a metropolitan university in Australia. An advisory group was established to provide governance and to identify key informants and participants. Focus group discussions (n = 2) and semi-structured interviews (n = 22) were facilitated with representatives from a broad range of disciplines. In addition, a survey, a review of relevant websites (n = 15) and a broad review of the literature were undertaken to elicit information on collaborative research networks and perceived needs and factors that would support their involvement in a multi-disciplinary collaborative research network. Findings were de-identified and broad themes were identified. Participants identified human factors as having priority for developing and sustaining a collaborative research network. In particular, leadership, a shared vision and a communication plan that includes social media were identified as crucial for sustaining an imaging network in health research. It is important to develop metrics that map relationships between network members and the role that communication tools can contribute to this process. This study confirms that human factors remain significant across a range of collaborative endeavours. The use of focus group discussions, interviews, and literature and website reviews means we can now strongly recommend the primacy of human factors. More work is needed to identify how the network operates and what specific indicators or metrics help build the capacity of clinicians and scientists to participate in translational research.

  1. Miniature EVA Software Defined Radio

    NASA Technical Reports Server (NTRS)

    Pozhidaev, Aleksey

    2012-01-01

    As NASA embarks upon developing the Next-Generation Extra Vehicular Activity (EVA) Radio for deep space exploration, the demands on EVA battery life will substantially increase. The number of modes and frequency bands required will continue to grow in order to enable efficient and complex multi-mode operations including communications, navigation, and tracking applications. Whether conducting astronaut excursions, communicating to soldiers, or first responders responding to emergency hazards, NASA has developed an innovative, affordable, miniaturized, power-efficient software defined radio that offers unprecedented power-efficient flexibility. This lightweight, programmable, S-band, multi-service, frequency- agile EVA software defined radio (SDR) supports data, telemetry, voice, and both standard and high-definition video. Features include a modular design, an easily scalable architecture, and the EVA SDR allows for both stationary and mobile battery powered handheld operations. Currently, the radio is equipped with an S-band RF section. However, its scalable architecture can accommodate multiple RF sections simultaneously to cover multiple frequency bands. The EVA SDR also supports multiple network protocols. It currently implements a Hybrid Mesh Network based on the 802.11s open standard protocol. The radio targets RF channel data rates up to 20 Mbps and can be equipped with a real-time operating system (RTOS) that can be switched off for power-aware applications. The EVA SDR's modular design permits implementation of the same hardware at all Network Nodes concept. This approach assures the portability of the same software into any radio in the system. It also brings several benefits to the entire system including reducing system maintenance, system complexity, and development cost.

  2. Forging a link between mentoring and collaboration: a new training model for implementation science.

    PubMed

    Luke, Douglas A; Baumann, Ana A; Carothers, Bobbi J; Landsverk, John; Proctor, Enola K

    2016-10-13

    Training investigators for the rapidly developing field of implementation science requires both mentoring and scientific collaboration. Using social network descriptive analyses, visualization, and modeling, this paper presents results of an evaluation of the mentoring and collaborations fostered over time through the National Institute of Mental Health (NIMH) supported by Implementation Research Institute (IRI). Data were comprised of IRI participant self-reported collaborations and mentoring relationships, measured in three annual surveys from 2012 to 2014. Network descriptive statistics, visualizations, and network statistical modeling were conducted to examine patterns of mentoring and collaboration among IRI participants and to model the relationship between mentoring and subsequent collaboration. Findings suggest that IRI is successful in forming mentoring relationships among its participants, and that these mentoring relationships are related to future scientific collaborations. Exponential random graph network models demonstrated that mentoring received in 2012 was positively and significantly related to the likelihood of having a scientific collaboration 2 years later in 2014 (p = 0.001). More specifically, mentoring was significantly related to future collaborations focusing on new research (p = 0.009), grant submissions (p = 0.003), and publications (p = 0.017). Predictions based on the network model suggest that for every additional mentoring relationships established in 2012, the likelihood of a scientific collaboration 2 years later is increased by almost 7 %. These results support the importance of mentoring in implementation science specifically and team science more generally. Mentoring relationships were established quickly and early by the IRI core faculty. IRI fellows reported increasing scientific collaboration of all types over time, including starting new research, submitting new grants, presenting research results, and publishing peer-reviewed papers. Statistical network models demonstrated that mentoring was strongly and significantly related to subsequent scientific collaboration, which supported a core design principle of the IRI. Future work should establish the link between mentoring and scientific productivity. These results may be of interest to team science, as they suggest the importance of mentoring for future team collaborations, as well as illustrate the utility of network analysis for studying team characteristics and activities.

  3. Comparing Notes: Collaborative Networks, Breeding Environments, and Organized Crime

    NASA Astrophysics Data System (ADS)

    Hernández, Alejandro

    Collaborative network theory can be useful in refining current understanding of criminal networks and aid in understanding their evolution. Drug trafficking organizations that operate in the region directly north of Colombia’s Valle del Cauca department and the “collection agencies” that operate in the Colombian city of Cali have abandoned hierarchical organizational structures and have become networked-based entities. Through the exposition of Camarinha-Matos and Afsarmanesh’s business networking ideas, this chapter examines the similarities and differences between the application of collaborative networks in licit enterprises, such as small and medium enterprises in Europe, and how the networks might be used by illicit criminal enterprises in Colombia.

  4. Software-Defined Architectures for Spectrally Efficient Cognitive Networking in Extreme Environments

    NASA Astrophysics Data System (ADS)

    Sklivanitis, Georgios

    The objective of this dissertation is the design, development, and experimental evaluation of novel algorithms and reconfigurable radio architectures for spectrally efficient cognitive networking in terrestrial, airborne, and underwater environments. Next-generation wireless communication architectures and networking protocols that maximize spectrum utilization efficiency in congested/contested or low-spectral availability (extreme) communication environments can enable a rich body of applications with unprecedented societal impact. In recent years, underwater wireless networks have attracted significant attention for military and commercial applications including oceanographic data collection, disaster prevention, tactical surveillance, offshore exploration, and pollution monitoring. Unmanned aerial systems that are autonomously networked and fully mobile can assist humans in extreme or difficult-to-reach environments and provide cost-effective wireless connectivity for devices without infrastructure coverage. Cognitive radio (CR) has emerged as a promising technology to maximize spectral efficiency in dynamically changing communication environments by adaptively reconfiguring radio communication parameters. At the same time, the fast developing technology of software-defined radio (SDR) platforms has enabled hardware realization of cognitive radio algorithms for opportunistic spectrum access. However, existing algorithmic designs and protocols for shared spectrum access do not effectively capture the interdependencies between radio parameters at the physical (PHY), medium-access control (MAC), and network (NET) layers of the network protocol stack. In addition, existing off-the-shelf radio platforms and SDR programmable architectures are far from fulfilling runtime adaptation and reconfiguration across PHY, MAC, and NET layers. Spectrum allocation in cognitive networks with multi-hop communication requirements depends on the location, network traffic load, and interference profile at each network node. As a result, the development and implementation of algorithms and cross-layer reconfigurable radio platforms that can jointly treat space, time, and frequency as a unified resource to be dynamically optimized according to inter- and intra-network interference constraints is of fundamental importance. In the next chapters, we present novel algorithmic and software/hardware implementation developments toward the deployment of spectrally efficient terrestrial, airborne, and underwater wireless networks. In Chapter 1 we review the state-of-art in commercially available SDR platforms, describe their software and hardware capabilities, and classify them based on their ability to enable rapid prototyping and advance experimental research in wireless networks. Chapter 2 discusses system design and implementation details toward real-time evaluation of a software-radio platform for all-spectrum cognitive channelization in the presence of narrowband or wideband primary stations. All-spectrum channelization is achieved by designing maximum signal-to-interference-plus-noise ratio (SINR) waveforms that span the whole continuum of the device-accessible spectrum, while satisfying peak power and interference temperature (IT) constraints for the secondary and primary users, respectively. In Chapter 3, we introduce the concept of all-spectrum channelization based on max-SINR optimized sparse-binary waveforms, we propose optimal and suboptimal waveform design algorithms, and evaluate their SINR and bit-error-rate (BER) performance in an SDR testbed. Chapter 4 considers the problem of channel estimation with minimal pilot signaling in multi-cell multi-user multi-input multi-output (MIMO) systems with very large antenna arrays at the base station, and proposes a least-squares (LS)-type algorithm that iteratively extracts channel and data estimates from a short record of data measurements. Our algorithmic developments toward spectrally-efficient cognitive networking through joint optimization of channel access code-waveforms and routes in a multi-hop network are described in Chapter 5. Algorithmic designs are software optimized on heterogeneous multi-core general-purpose processor (GPP)-based SDR architectures by leveraging a novel software-radio framework that offers self-optimization and real-time adaptation capabilities at the PHY, MAC, and NET layers of the network protocol stack. Our system design approach is experimentally validated under realistic conditions in a large-scale hybrid ground-air testbed deployment. Chapter 6 reviews the state-of-art in software and hardware platforms for underwater wireless networking and proposes a software-defined acoustic modem prototype that enables (i) cognitive reconfiguration of PHY/MAC parameters, and (ii) cross-technology communication adaptation. The proposed modem design is evaluated in terms of effective communication data rate in both water tank and lake testbed setups. In Chapter 7, we present a novel receiver configuration for code-waveform-based multiple-access underwater communications. The proposed receiver is fully reconfigurable and executes (i) all-spectrum cognitive channelization, and (ii) combined synchronization, channel estimation, and demodulation. Experimental evaluation in terms of SINR and BER show that all-spectrum channelization is a powerful proposition for underwater communications. At the same time, the proposed receiver design can significantly enhance bandwidth utilization. Finally, in Chapter 8, we focus on challenging practical issues that arise in underwater acoustic sensor network setups where co-located multi-antenna sensor deployment is not feasible due to power, computation, and hardware limitations, and design, implement, and evaluate an underwater receiver structure that accounts for multiple carrier frequency and timing offsets in virtual (distributed) MIMO underwater systems.

  5. The Telecommunications and Data Acquisition Report

    NASA Technical Reports Server (NTRS)

    Posner, E. C. (Editor)

    1989-01-01

    Developments in programs managed by JPL's Office of Telecommunications and Data Acquisition (TDA) are provided. Activities of the Deep Space Network and its associated Ground Communications Facility in planning, in supporting research and technology, in implementation, and in operations are reported in space communications, radio navigation, radio science, and ground-based radio and radar astronomy.

  6. The Telecommunications and Data Acquisition Progress Report 42-123

    NASA Technical Reports Server (NTRS)

    Yuen, Joseph H. (Editor)

    1995-01-01

    The progress of research programs monitored by the Jet Propulsion Laboratory's Telecommunications and Mission Operations Directorate (TMOD) are presented in this quarterly document. Areas monitored include space communications, radio navigation, radio science, ground-based radio and radar astronomy, information systems, and all other communication and research technology activities for the Deep Space Network (DSN).

  7. VLA radio upper limit on Type IIn Supernova 2007pk

    NASA Astrophysics Data System (ADS)

    Chandra, Poonam; Soderberg, Alicia

    2007-11-01

    Poonam Chandra and Alicia Soderberg report on behalf of a larger collaboration: We observed Type IIn supernova SN 2007pk (CBET 1129) with the VLA in 8.46 GHz band on 2007, November 12.20 UT, 1.89 days since discovery (CBET 1129). We do not detect radio emission from the SN position (CBET 1129). The flux density at the SN position is 11 +/-26 uJy.

  8. Optimal satisfaction degree in energy harvesting cognitive radio networks

    NASA Astrophysics Data System (ADS)

    Li, Zan; Liu, Bo-Yang; Si, Jiang-Bo; Zhou, Fu-Hui

    2015-12-01

    A cognitive radio (CR) network with energy harvesting (EH) is considered to improve both spectrum efficiency and energy efficiency. A hidden Markov model (HMM) is used to characterize the imperfect spectrum sensing process. In order to maximize the whole satisfaction degree (WSD) of the cognitive radio network, a tradeoff between the average throughput of the secondary user (SU) and the interference to the primary user (PU) is analyzed. We formulate the satisfaction degree optimization problem as a mixed integer nonlinear programming (MINLP) problem. The satisfaction degree optimization problem is solved by using differential evolution (DE) algorithm. The proposed optimization problem allows the network to adaptively achieve the optimal solution based on its required quality of service (Qos). Numerical results are given to verify our analysis. Project supported by the National Natural Science Foundation of China (Grant No. 61301179), the Doctorial Programs Foundation of the Ministry of Education of China (Grant No. 20110203110011), and the 111 Project (Grant No. B08038).

  9. Ciência & Saúde Coletiva: scientific production analysis and collaborative research networks.

    PubMed

    Conner, Norma; Provedel, Attilio; Maciel, Ethel Leonor Noia

    2017-03-01

    The purpose of this metric and descriptive study was to identify the most productive authors and their collaborative research networks from articles published in Ciência & Saúde Coletiva between, 2005, and 2014. Authors meeting the cutoff criteria of at least 10 articles were considered the most productive authors. VOSviewer and Network Workbench technologies were applied for visual representations of collaborative research networks involving the most productive authors in the period. Initial analysis recovered 2511 distinct articles, with 8920 total authors with an average of 3.55 authors per article. Author analysis revealed 6288 distinct authors, 24 of these authors were identified as the most productive. These 24 authors generated 287 articles with an average of 4.31 authors per article, and represented 8 separate collaborative partnerships, the largest of which had 14 authors, indicating a significant degree of collaboration among these authors. This analysis provides a visual representation of networks of knowledge development in public health and demonstrates the usefulness of VOSviewer and Network Workbench technologies in future research.

  10. The Arecibo Remote Command Center Network

    NASA Astrophysics Data System (ADS)

    Crawford, Fronefield; Jenet, Fredrick; Christy, Brian; Dolch, Timothy; Guerreo-Miller, Alma; Quetschke, Volker; Siemens, Xavier; Smith, Tristan L.; Stovall, Kevin; Wade, Leslie; Wade, Madeline

    2017-01-01

    The Arecibo Remote Command Center (ARCC) network is an education, research, and training program for undergraduates, graduate students, and postdocs spanning multiple institutions. ARCC members use the Arecibo 305-m radio telescope to remotely conduct pulsar survey and timing observations, and they search the data collected to find new radio pulsars using a custom pulsar candidate viewer. Timing data are used in the ongoing NANOGrav search for gravitational waves using pulsar timing arrays. The ARCC program also serves as an effective introduction for students to radio pulsar research. Currently ARCC has seven institutional members and dozens of participants. Our poster provides some general background about the ARCC program at Franklin and Marshall College and serves as a catalyst for in-person conversations and discussions about ARCC, including the benefits of joining the ARCC network and some specifics on how to join.

  11. Advanced teleprocessing systems

    NASA Astrophysics Data System (ADS)

    Kleinrock, L.; Gerla, M.

    1982-09-01

    This Annual Technical Report covers research covering the period from October 1, 1981 to September 30, 1982. This contract has three primary designated research areas: packet radio systems, resource sharing and allocation, and distributed processing and control. This report contains abstracts of publications which summarize research results in these areas followed by the main body of the report which is devoted to a study of channel access protocols that are executed by the nodes of a network to schedule their transmissions on multi-access broadcast channel. In particular the main body consists of a Ph.D. dissertation, Channel Access Protocols for Multi-Hop Broadcast Packet Radio Networks. This work discusses some new channel access protocols useful for mobile radio networks. Included is an analysis of slotted ALOHA and some tight bounds on the performance of all possible protocols in a mobile environment.

  12. Scientific Collaboration in Chinese Nursing Research: A Social Network Analysis Study.

    PubMed

    Hou, Xiao-Ni; Hao, Yu-Fang; Cao, Jing; She, Yan-Chao; Duan, Hong-Mei

    2016-01-01

    Collaboration has become very important in research and in technological progress. Coauthorship networks in different fields have been intensively studied as an important type of collaboration in recent years. Yet there are few published reports about collaboration in the field of nursing. This article aimed to reveal the status and identify the key features of collaboration in the field of nursing in China. Using data from the top 10 nursing journals in China from 2003 to 2013, we constructed a nursing scientific coauthorship network using social network analysis. We found that coauthorship was a common phenomenon in the Chinese nursing field. A coauthorship network with 228 subnetworks formed by 1428 nodes was constructed. The network was relatively loose, and most subnetworks were of small scales. Scholars from Shanghai and from military medical system were at the center of the Chinese nursing scientific coauthorship network. We identified the authors' positions and influences according to the research output and centralities of each author. We also analyzed the microstructure and the evolution over time of the maximum subnetwork.

  13. The Audacity of Fiber-Wireless (FiWi) Networks

    NASA Astrophysics Data System (ADS)

    Maier, Martin; Ghazisaidi, Navid; Reisslein, Martin

    A plethora of enabling optical and wireless technologies have been emerging that can be used to build future-proof bimodal fiber-wireless (FiWi) broadband access networks. After overviewing key enabling radio-over-fiber (RoF) and radio-and-fiber (R&F) technologies and briefly surveying the state of the art of FiWi networks, we introduce an Ethernet-based access-metro FiWi network, called SuperMAN, that integrates next-generation WiFi and WiMAX networks with WDM-enhanced EPON and RPR networks. Throughout the paper we pay close attention to the technical challenges and opportunities of FiWi networks, but also elaborate on their societal benefits and potential to shift the current research focus from optical-wireless networking to the exploitation of personal and in-home computing facilities to create new unforeseen services and applications as we are about to enter the Petabyte age.

  14. Optical RRH working in an all-optical fronthaul network

    NASA Astrophysics Data System (ADS)

    Zakrzewski, Zbigniew

    2017-12-01

    The paper presents an example of an optical RRH (Remote Radio Head) design, which is equipped with photonic components for direct connection to an all-optical network. The features that can be fulfilled by an all-optical network are indicated to support future 5G mobile networks. The demand for optical bandwidth in fronthaul/midhaul distribution network links, working in D-RoF and A-RoF formats was performed. The increase in demand is due to the very large traffic generated by the Optical Massive-MIMO RRH/RRU will work in format of an Active-Distributed Antenna System (A-DAS). An exemplary next-generation mobile network that will utilize O-RRH and an all-optical backbone is presented. All components of presented network will work in the Centralized/Cloud Radio Access Network (C-RAN) architecture, which is achievable by control with the use of the OpenFlow (OF).

  15. Reconfigurable radio-over-fiber system based on optical switch and tunable filter

    NASA Astrophysics Data System (ADS)

    Li, Xiao; Yin, Rui; Ji, Wei; Sun, Kai; Zhang, Shicheng

    2017-09-01

    As the best candidate for wireless-access networks, radio-over-fiber (RoF) technology can carry a variety of business. It is necessary to provide differentiated services for different users, so the network needs to produce signals with different modulation formats and different frequencies. A reconfigurable RoF system based on a switch and tunable optical filter that can realize modulation format conversion and multiple frequency signal switching functions is designed. It has a good performance in terms of bit error rate and an eye diagram. The design can help to use radio frequency resources efficiently and make dynamic bandwidth resources controllable.

  16. News and Views: Research council resource allocations: managing demand; e-MERLIN radio telescope network is up and running

    NASA Astrophysics Data System (ADS)

    2011-02-01

    The research councils discovered in December the allocation of money from the UK government's Comprehensive Spending Review, and have set out their delivery plans outlining how they will spend it. Details and decisions will follow consultation in the coming months. The first image from eMerlin, the UK's national radio astronomy facility, shows the power of the enhanced network of radio telescopes spread over 220 km and now linked by fibre optics. These links and advanced receivers will allow astronomers to see in a single day what would have previously taken them more than a year of observations.

  17. Dynamic analysis of interhospital collaboration and competition: empirical evidence from an Italian regional health system.

    PubMed

    Mascia, Daniele; Di Vincenzo, Fausto; Cicchetti, Americo

    2012-05-01

    Policymakers stimulate competition in universalistic health-care systems while encouraging the formation of service provision networks among hospital organizations. This article addresses a gap in the extant literature by empirically analyzing simultaneous collaboration and competition between hospitals within the Italian National Health Service, where important procompetition reforms have been implemented. To explore how rising competition between hospitals relates to their propensity to collaborate with other local providers. Longitudinal data on interhospital collaboration and competition collected in an Italian region from 2003 to 2007 are analyzed. Social network analysis techniques are applied to study the structure and dynamics of interhospital collaboration. Negative binomial regressions are employed to explore how interhospital competition relates to the collaborative network over time. Competition among providers does not hinder interhospital collaboration. Collaboration is primarily local, with resource complementarity and differentials in the volume of activity and hospital performance explaining the propensity to collaborate. Formation of collaborative networks among hospitals is not hampered by reforms aimed at fostering market forces. Because procompetition reforms elicit peculiar forms of managed competition in universalistic health systems, studies are needed to clarify whether the positive association between interhospital competition and collaboration can be generalized to other health-care settings. Copyright © 2012 Elsevier Ireland Ltd. All rights reserved.

  18. Performance analysis of multi-radio routing protocol in cognitive radio ad hoc networks under different path failure rate

    NASA Astrophysics Data System (ADS)

    Che-Aron, Z.; Abdalla, A. H.; Abdullah, K.; Hassan, W. H.

    2013-12-01

    In recent years, Cognitive Radio (CR) technology has largely attracted significant studies and research. Cognitive Radio Ad Hoc Network (CRAHN) is an emerging self-organized, multi-hop, wireless network which allows unlicensed users to opportunistically access available licensed spectrum bands for data communication under an intelligent and cautious manner. However, in CRAHNs, a lot of failures can easily occur during data transmission caused by PU (Primary User) activity, topology change, node fault, or link degradation. In this paper, an attempt has been made to evaluate the performance of the Multi-Radio Link-Quality Source Routing (MR-LQSR) protocol in CRAHNs under different path failure rate. In the MR-LQSR protocol, the Weighted Cumulative Expected Transmission Time (WCETT) is used as the routing metric. The simulations are carried out using the NS-2 simulator. The protocol performance is evaluated with respect to performance metrics like average throughput, packet loss, average end-to-end delay and average jitter. From the simulation results, it is observed that the number of path failures depends on the PUs number and mobility rate of SUs (Secondary Users). Moreover, the protocol performance is greatly affected when the path failure rate is high, leading to major service outages.

  19. Received signal strength and local terrain profile data for radio network planning and optimization at GSM frequency bands.

    PubMed

    Popoola, Segun I; Atayero, Aderemi A; Faruk, Nasir

    2018-02-01

    The behaviour of radio wave signals in a wireless channel depends on the local terrain profile of the propagation environments. In view of this, Received Signal Strength (RSS) of transmitted signals are measured at different points in space for radio network planning and optimization. However, these important data are often not publicly available for wireless channel characterization and propagation model development. In this data article, RSS data of a commercial base station operating at 900 and 1800 MHz were measured along three different routes of Lagos-Badagry Highway, Nigeria. In addition, local terrain profile data of the study area (terrain elevation, clutter height, altitude, and the distance of the mobile station from the base station) are extracted from Digital Terrain Map (DTM) to account for the unique environmental features. Statistical analyses and probability distributions of the RSS data are presented in tables and graphs. Furthermore, the degree of correlations (and the corresponding significance) between the RSS and the local terrain parameters were computed and analyzed for proper interpretations. The data provided in this article will help radio network engineers to: predict signal path loss; estimate radio coverage; efficiently reuse limited frequencies; avoid interferences; optimize handover; and adjust transmitted power level.

  20. Implementation of a Web-Based Collaborative Process Planning System

    NASA Astrophysics Data System (ADS)

    Wang, Huifen; Liu, Tingting; Qiao, Li; Huang, Shuangxi

    Under the networked manufacturing environment, all phases of product manufacturing involving design, process planning, machining and assembling may be accomplished collaboratively by different enterprises, even different manufacturing stages of the same part may be finished collaboratively by different enterprises. Based on the self-developed networked manufacturing platform eCWS(e-Cooperative Work System), a multi-agent-based system framework for collaborative process planning is proposed. In accordance with requirements of collaborative process planning, share resources provided by cooperative enterprises in the course of collaboration are classified into seven classes. Then a reconfigurable and extendable resource object model is built. Decision-making strategy is also studied in this paper. Finally a collaborative process planning system e-CAPP is developed and applied. It provides strong support for distributed designers to collaboratively plan and optimize product process though network.

  1. SibRank: Signed bipartite network analysis for neighbor-based collaborative ranking

    NASA Astrophysics Data System (ADS)

    Shams, Bita; Haratizadeh, Saman

    2016-09-01

    Collaborative ranking is an emerging field of recommender systems that utilizes users' preference data rather than rating values. Unfortunately, neighbor-based collaborative ranking has gained little attention despite its more flexibility and justifiability. This paper proposes a novel framework, called SibRank that seeks to improve the state of the art neighbor-based collaborative ranking methods. SibRank represents users' preferences as a signed bipartite network, and finds similar users, through a novel personalized ranking algorithm in signed networks.

  2. Medium Access Control Protocols for Cognitive Radio Ad Hoc Networks: A Survey

    PubMed Central

    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

  3. Hospital networks: how to make them work in Belgium? Facilitators and barriers of different governance models.

    PubMed

    De Pourcq, Kaat; De Regge, Melissa; Van den Heede, Koen; Van de Voorde, Carine; Gemmel, Paul; Eeckloo, Kristof

    2018-03-29

    Objectives This study aims to identify the facilitators and barriers to governance models of hospital collaborations. The country-specific characteristics of the Belgian healthcare system and legislation are taken into account. Methods A case study was carried out in six Belgian hospital collaborations. Different types of governance models were selected: two health systems, two participant-governed networks, and two lead-organization-governed networks. Within these collaborations, 43 people were interviewed. Results All structures have both advantages and disadvantages. It is important that the governance model fits the network. However, structural, procedural, and especially contextual factors also affect the collaborations, such as alignment of hospitals' and professionals' goals, competition, distance, level of integrated care, time needed for decision-making, and legal and financial incentives. Conclusion The fit between the governance model and the collaboration can facilitate the functioning of a collaboration. The main barriers we identified are contextual factors. The Belgian government needs to play a major role in facilitating collaboration.

  4. Interstellar Molecules in K-12 Education

    NASA Astrophysics Data System (ADS)

    Kuiper, T. B. H.; Hofstadter, M. D.; Levin, S. M.; MacLaren, D.

    2006-12-01

    The Lewis Center for Educational Research (LCER) and the Jet Propulsion Laboratory (JPL) collaborate in a K-12 educational project in which students conduct observations for several research programs led by radio astronomers. The Goldstone-Apple Valley Radio Telescope (GAVRT) program provides participating teachers with curriculum elements, based on the students' observing experiences, which support national and state academic standards. The current program is based on 2.2-GHz and 8.4-GHz radiometric observations of variable sources. The research programs monitor Jupiter, Uranus, and a selected set of quasars. The telescope is a decommissioned NASA Deep Space Network antenna at Goldstone, California. In the next three years, a second telescope will be added. This telescope will at least operate at the above frequencies as well as 6 GHz and 12 GHz. Possibly, it will operate in a continuous band from 1.2 GHz to 14 GHz. In either case, the telescope will be able to observe at least the 6.6-GHz and 12.2-GHz methanol maser lines. The success of the GAVRT program depends critically on the participation of scientists committed to the research who have the ability and enthusiasm for interacting with K-12 students, typically through teleconferences. The scientists will initially work with the LCER staff to create curriculum elements around their observing program.

  5. Network collaboration of organisations for homeless individuals in the Montreal region

    PubMed Central

    Fleury, Marie-Josée; Grenier, Guy; Lesage, Alain; Ma, Nan; Ngui, André Ngamini

    2014-01-01

    Introduction We know little about the intensity and determinants of interorganisational collaboration within the homeless network. This study describes the characteristics and relationships (along with the variables predicting their degree of interorganisational collaboration) of 68 organisations of such a network in Montreal (Quebec, Canada). Theory and methods Data were collected primarily through a self-administered questionnaire. Descriptive analyses were conducted followed by social network and multivariate analyses. Results The Montreal homeless network has a high density (50.5%) and a decentralised structure and maintains a mostly informal collaboration with the public and cross-sectorial sectors. The network density showed more frequent contacts among four types of organisations which could point to the existence of cliques. Four variables predicted interorganisational collaboration: organisation type, number of services offered, volume of referrals and satisfaction with the relationships with public organisations. Conclusions and discussion The Montreal homeless network seems adequate to address non-complex homelessness problems. Considering, however, that most homeless individuals present chronic and complex profiles, it appears necessary to have a more formal and better integrated network of homeless organisations, particularly in the health and social service sectors, in order to improve services. PMID:24520216

  6. Innovation by coercion: Emerging institutionalization of university-industry collaborations in Russia.

    PubMed

    Bychkova, Olga

    2016-08-01

    This article explores the emerging institutionalization of collaborative university-industry networks in Russia. The Russian government has attempted to use a top-down public policy scheme to stimulate and promote network-building in the R&D sector. In order to understand the initial organizational responses that universities and companies select while structuring collaborations, the article utilizes conceptual perspectives from institutional theory, especially drawing on arguments from strategic choice, network-building, and network failure studies.

  7. Collaboration Levels in Asynchronous Discussion Forums: A Social Network Analysis Approach

    ERIC Educational Resources Information Center

    Luhrs, Cecilia; McAnally-Salas, Lewis

    2016-01-01

    Computer Supported Collaborative Learning literature relates high levels of collaboration to enhanced learning outcomes. However, an agreement on what is considered a high level of collaboration is unclear, especially if a qualitative approach is taken. This study describes how methods of Social Network Analysis were used to design a collaboration…

  8. Challenges for Wireless Mesh Networks to provide reliable carrier-grade services

    NASA Astrophysics Data System (ADS)

    von Hugo, D.; Bayer, N.

    2011-08-01

    Provision of mobile and wireless services today within a competitive environment and driven by a huge amount of steadily emerging new services and applications is both challenge and chance for radio network operators. Deployment and operation of an infrastructure for mobile and wireless broadband connectivity generally requires planning effort and large investments. A promising approach to reduce expenses for radio access networking is offered by Wireless Mesh Networks (WMNs). Here traditional dedicated backhaul connections to each access point are replaced by wireless multi-hop links between neighbouring access nodes and few gateways to the backbone employing standard radio technology. Such a solution provides at the same time high flexibility in both deployment and the amount of offered capacity and shall reduce overall expenses. On the other hand currently available mesh solutions do not provide carrier grade service quality and reliability and often fail to cope with high traffic load. EU project CARMEN (CARrier grade MEsh Networks) was initiated to incorporate different heterogeneous technologies and new protocols to allow for reliable transmission over "best effort" radio channels, to support a reliable mobility and network management, self-configuration and dynamic resource usage, and thus to offer a permanent or temporary broadband access at high cost efficiency. The contribution provides an overview on preliminary project results with focus on main technical challenges from a research and implementation point of view. Especially impact of mesh topology on the overall system performance in terms of throughput and connection reliability and aspects of a dedicated hybrid mobility management solution will be discussed.

  9. The Telecommunications and Data Acquisition Report

    NASA Technical Reports Server (NTRS)

    Posner, E. C. (Editor)

    1983-01-01

    Developments in programs in telecommunication and data acquisition in space communications, radio navigation, radio science, and ground based radio astronomy are reported. Activities of the deep space network (DSN) and its associated ground communication facility (GCF) in planning, supporting research and technology, implementation, and in operations are outlined. The publication of reports on the application of radio interferometry at microwave frequencies for geodynamic measurements are presented. Implementation and operation for searching the microwave spectrum is reported.

  10. Low cost satellite land mobile service for nationwide applications

    NASA Technical Reports Server (NTRS)

    Weiss, J. A.

    1978-01-01

    A satellite land mobile system using mobile radios in the UHF band, and Ku-band Communications Routing Terminals (earth stations) for a nationwide connection from any mobile location to any fixed or mobile location, and from any fixed location to any mobile location is proposed. The proposed nationwide satellite land mobile service provides: telephone network quality (1 out of 100 blockage) service, complete privacy for all the users, operation similar to the telephone network, alternatives for data services up to 32 Kbps data rates, and a cost effective and practical mobile radio compatible with system sizes ranging from 10,000 to 1,000,000 users. Seven satellite alternatives (ranging from 30 ft diameter dual beam antenna to 210 ft diameter 77 beam antenna) along with mobile radios having a sensitivity figure of merit (G/T) of -15 dB/deg K are considered. Optimized mobile radio user costs are presented as a function of the number of users with the satellite and mobile radio alternatives as system parameters.

  11. IA-Regional-Radio - Social Network for Radio Recommendation

    NASA Astrophysics Data System (ADS)

    Dziczkowski, Grzegorz; Bougueroua, Lamine; Wegrzyn-Wolska, Katarzyna

    This chapter describes the functions of a system proposed for the music hit recommendation from social network data base. This system carries out the automatic collection, evaluation and rating of music reviewers and the possibility for listeners to rate musical hits and recommendations deduced from auditor's profiles in the form of regional Internet radio. First, the system searches and retrieves probable music reviews from the Internet. Subsequently, the system carries out an evaluation and rating of those reviews. From this list of music hits, the system directly allows notation from our application. Finally, the system automatically creates the record list diffused each day depending on the region, the year season, the day hours and the age of listeners. Our system uses linguistics and statistic methods for classifying music opinions and data mining techniques for recommendation part needed for recorded list creation. The principal task is the creation of popular intelligent radio adaptive on auditor's age and region - IA-Regional-Radio.

  12. 77 FR 55715 - Medical Area Body Network

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-09-11

    ... operating in accordance with the rules. 13. The 2370-2390 MHz band is used for radio astronomy operations in... to ensure protection of radio astronomy operations at the Arecibo site. 14. Lastly, the Commission...

  13. Official crime data versus collaborative crime mapping at a Brazilian city

    NASA Astrophysics Data System (ADS)

    Brito, P. L.; Jesus, E. G. V.; Sant'Ana, R. M. S.; Martins, C.; Delgado, J. P. M.; Fernandes, V. O.

    2014-11-01

    In July of 2013 a group of undergraduate students from the Federal University of Bahia, Brazil, published a collaborative web map called "Where I Was Robbed". Their initial efforts in publicizing their web map were restricted to announce it at a local radio as a tool of social interest. In two months the map had almost 10.000 reports, 155 reports per day and people from more the 350 cities had already reported a crime. The present study consists in an investigation about this collaborative web map spatial correlation to official robbery data registered at the Secretary of Public Safety database, for the city of Salvador, Bahia. Kernel density estimator combined with map algebra was used to the investigation. Spatial correlations with official robbery data for the city of Salvador were not found initially, but after standardizing collaborative data and mining official registers, both data pointed at very similar areas as the main hot spots for pedestrian robbery. Both areas are located at two of the most economical active areas of the city, although web map crimes reports were more concentrated in an area with higher income population. This results and discussions indicates that this collaborative application is been used mainly by mid class and upper class parcel of the city population, but can still provide significant information on public safety priority areas. Therefore, extended divulgation, on local papers, radio and TV, of the collaborative crime map application and partnership with official agencies are strongly recommended.

  14. Patterns in PARTNERing across Public Health Collaboratives.

    PubMed

    Bevc, Christine A; Retrum, Jessica H; Varda, Danielle M

    2015-10-05

    Inter-organizational networks represent one of the most promising practice-based approaches in public health as a way to attain resources, share knowledge, and, in turn, improve population health outcomes. However, the interdependencies and effectiveness related to the structure, management, and costs of these networks represents a critical item to be addressed. The objective of this research is to identify and determine the extent to which potential partnering patterns influence the structure of collaborative networks. This study examines data collected by PARTNER, specifically public health networks (n = 162), to better understand the structured relationships and interactions among public health organizations and their partners, in relation to collaborative activities. Combined with descriptive analysis, we focus on the composition of public health collaboratives in a series of Exponential Random Graph (ERG) models to examine the partnerships between different organization types to identify the attribute-based effects promoting the formation of network ties within and across collaboratives. We found high variation within and between these collaboratives including composition, diversity, and interactions. The findings of this research suggest common and frequent types of partnerships, as well as opportunities to develop new collaborations. The result of this analysis offer additional evidence to inform and strengthen public health practice partnerships.

  15. Network Analysis of an Emergent Massively Collaborative Creation on Video Sharing Website

    NASA Astrophysics Data System (ADS)

    Hamasaki, Masahiro; Takeda, Hideaki; Nishimura, Takuichi

    The Web technology enables numerous people to collaborate in creation. We designate it as massively collaborative creation via the Web. As an example of massively collaborative creation, we particularly examine video development on Nico Nico Douga, which is a video sharing website that is popular in Japan. We specifically examine videos on Hatsune Miku, a version of a singing synthesizer application software that has inspired not only song creation but also songwriting, illustration, and video editing. As described herein, creators of interact to create new contents through their social network. In this paper, we analyzed the process of developing thousands of videos based on creators' social networks and investigate relationships among creation activity and social networks. The social network reveals interesting features. Creators generate large and sparse social networks including some centralized communities, and such centralized community's members shared special tags. Different categories of creators have different roles in evolving the network, e.g., songwriters gather more links than other categories, implying that they are triggers to network evolution.

  16. US Space VLBI Proposed Outreach Web Site

    NASA Technical Reports Server (NTRS)

    2000-01-01

    The study of how VLBI might be pursued in space began in the late 1970's, when it was realized that the size of the earth was a serious limitation to the study of compact radio sources. By going to space, achieving angular resolution at radio wavelengths that could not be obtained with VLBI systems that were limited by the size of the earth, important tests could not be made of quasar models. The technology appeared to be within reach, and an early space VLBI concept, QUASAT, emerged as a joint project, involving both US and European scientists. In 1984, a workshop was held in Gross Enzerdorf, Austria, under joint sponsorship of NASA and the European Space Agency (ESA). The principal conclusion of the workshop was that a VLBI station in space, telemetering its data to ground data stations, working in connection with ground-based radio telescopes, would give the opportunity to achieve angular resolution of a few tens of micro-arc-seconds, and could develop high-quality radio maps of many classes of radio sources. The ground telemetry stations would also function as the source of a stable local oscillator for the spacecraft, which needs a highly stable frequency reference. The Deep Space Network of NASA could play a vital role in both the frequency-locking system and data acquisition. One outcome of the Gross Enzerdorf workshop was the convening, by COSPAR, of an ad hoc Committee on Space VLBI, to review and recommend procedures by which international collaboration on VLBI in space might be coordinated and promoted. In October 1985, the committee met in Budapest and recommended that the Inter-Agency Consultative Group (IACG) would be an appropriate body to coordinate VLBI activities in space. At the same time ESA convened a committee to explore the technical aspects of coordinating ground and space VLBI activities. At this stage both NASA and ESA were supporting preliminary studies of the QUASAT mission, with effective coordination between the two groups. The Soviet Union had also begun planning a mission with the clear intent to fly it as soon as the could; the mission was designated RadioAstron. In December 1985, the Soviets formed an international study team for the RadioAstron mission, holding the first meeting in Moscow. Subsequent meetings of this international committee were held in Budapest in May 1986 and in Moscow in December 1986. Thus, in 1986 there were three VLBI mission concepts under study: the NASA QUASAT mission, an ESA counterpart, and the Soviet RadioAstron mission.

  17. Scientific authorship and collaboration network analysis on malaria research in Benin: papers indexed in the web of science (1996-2016).

    PubMed

    Azondekon, Roseric; Harper, Zachary James; Agossa, Fiacre Rodrigue; Welzig, Charles Michael; McRoy, Susan

    2018-01-01

    To sustain the critical progress made, prioritization and a multidisciplinary approach to malaria research remain important to the national malaria control program in Benin. To document the structure of the malaria collaborative research in Benin, we analyze authorship of the scientific documents published on malaria from Benin. We collected bibliographic data from the Web Of Science on malaria research in Benin from January 1996 to December 2016. From the collected data, a mulitigraph co-authorship network with authors representing vertices was generated. An edge was drawn between two authors when they co-author a paper. We computed vertex degree, betweenness, closeness, and eigenvectors among others to identify prolific authors. We further assess the weak points and how information flow in the network. Finally, we perform a hierarchical clustering analysis, and Monte-Carlo simulations. Overall, 427 publications were included in this study. The generated network contained 1792 authors and 116,388 parallel edges which converted in a weighted graph of 1792 vertices and 95,787 edges. Our results suggested that prolific authors with higher degrees tend to collaborate more. The hierarchical clustering revealed 23 clusters, seven of which form a giant component containing 94% of all the vertices in the network. This giant component has all the characteristics of a small-world network with a small shortest path distance between pairs of three, a diameter of 10 and a high clustering coefficient of 0.964. However, Monte-Carlo simulations suggested our observed network is an unusual type of small-world network. Sixteen vertices were identified as weak articulation points within the network. The malaria research collaboration network in Benin is a complex network that seems to display the characteristics of a small-world network. This research reveals the presence of closed research groups where collaborative research likely happens only between members. Interdisciplinary collaboration tends to occur at higher levels between prolific researchers. Continuously supporting, stabilizing the identified key brokers and most productive authors in the Malaria research collaborative network is an urgent need in Benin. It will foster the malaria research network and ensure the promotion of junior scientists in the field.

  18. The Telecommunications and Data Acquisition Report

    NASA Technical Reports Server (NTRS)

    Yuen, Joseph H. (Editor)

    1994-01-01

    This quarterly publication provides archival reports on developments in programs in space communications, radio navigation, radio science, and ground-based radio and radar astronomy. It reports on activities of the Deep Space Network (DSN) in planning, supporting research and technology, implementation, and operations. Also included are standardization activities at the Jet Propulsion Laboratory for space data and information systems.

  19. The Telecommunications and Data Acquisition Report

    NASA Technical Reports Server (NTRS)

    Posner, E. C. (Editor)

    1983-01-01

    Archival reports on developments in programs managed by JPL's office of Telecommunications and Data Acquisition (TDA) are presented. In space communications, radio navigation, radio science, and ground-based radio astronomy, it reports on activities of the Deep Space Network (DSN) and its associated Ground Communications Facility (GCF) in planning, in supporting research and technology, in implementation, and in operations.

  20. The Collaborative Coordination of Special Interest Groups on the Telemedicine University Network (RUTE) in Brazil.

    PubMed

    de Lima Verde Brito, Thiago Delevidove; Baptista, Roberto Silva; de Lima Lopes, Paulo Roberto; Haddad, Ana Estela; Messina, Luiz Ary; Torres Pisa, Ivan

    2015-01-01

    In Brazil the Telemedicine University Network (Rede Universitária de Telemedicina RUTE) is an initiative that among others promotes collaboration between university hospitals, universities, and health professionals through information technology infrastructure and special interest groups (SIGs) support. This paper presents results of analyses on collaboration during implementation and coordination activities of RUTE SIGs. This study is based on descriptive statistics and data visualization previously collected by RUTE national coordination relative to the status in July 2014. The analysis through collaboration graph identified the strongest collaboration RUTE units. The graph also highlights the collaborative relationship of RUTE units in form of communities, the most collaborative with each other in a communion in the same SIGs, and the less the collaborative units in the network. It should be stated that the most active units are also the oldest in the community.

  1. Counterfeit Electronic Parts Controls in the Department of Defense Supply Chain

    DTIC Science & Technology

    2015-06-01

    Equipment Manufacturer RFID Radio Frequency Identification SASC Senate Armed Services Committee SECDEF Secretary of Defense SWPaC Space, Weight...radio frequency identification ( RFID ). Upon the use of that printer, the RFID is checked to ensure it is a valid platform, and will not work if the... RFID is not confirmed to be valid (Richetto, 2011). Greater collaboration with industry would also help with one of the primary drivers of

  2. ICC '86; Proceedings of the International Conference on Communications, Toronto, Canada, June 22-25, 1986, Conference Record. Volumes 1, 2, & 3

    NASA Astrophysics Data System (ADS)

    Papers are presented on ISDN, mobile radio systems and techniques for digital connectivity, centralized and distributed algorithms in computer networks, communications networks, quality assurance and impact on cost, adaptive filters in communications, the spread spectrum, signal processing, video communication techniques, and digital satellite services. Topics discussed include performance evaluation issues for integrated protocols, packet network operations, the computer network theory and multiple-access, microwave single sideband systems, switching architectures, fiber optic systems, wireless local communications, modulation, coding, and synchronization, remote switching, software quality, transmission, and expert systems in network operations. Consideration is given to wide area networks, image and speech processing, office communications application protocols, multimedia systems, customer-controlled network operations, digital radio systems, channel modeling and signal processing in digital communications, earth station/on-board modems, computer communications system performance evaluation, source encoding, compression, and quantization, and adaptive communications systems.

  3. Bridging the Gap between Students and Computers: Supporting Activity Awareness for Network Collaborative Learning with GSM Network

    ERIC Educational Resources Information Center

    Liu, C.-C.; Tao, S.-Y.; Nee, J.-N.

    2008-01-01

    The internet has been widely used to promote collaborative learning among students. However, students do not always have access to the system, leading to doubt in the interaction among the students, and reducing the effectiveness of collaborative learning, since the web-based collaborative learning environment relies entirely on the availability…

  4. Communicating with Voyager

    NASA Technical Reports Server (NTRS)

    Dumas, Larry N.; Hornstein, Robert M.

    1990-01-01

    The Deep Space Network for receiving Voyager 2 data is discussed. The functions of the earth-Voyager radio link are examined, including radiometrics, transmission of commands to the spacecraft, radio sciences, and the transmission of telemetry from the spacecraft to earth. The use of ranging, Doppler, and VLBI measurements to maintain position and velocity data on Voyager 2 is described. Emphasis is placed on the international tracking network for obtaining Voyager 2 data on Neptune and Triton.

  5. Multi-User Performance Issues in Wireless Impulse Radio Networks

    DTIC Science & Technology

    2004-01-01

    Performance Issues in Wireless Impulse Radio Networks 5a. CONTRACT NUMBER 5b. GRANT NUMBER 5c. PROGRAM ELEMENT NUMBER 6. AUTHOR( S ) 5d. PROJECT...NUMBER 5e. TASK NUMBER 5f. WORK UNIT NUMBER 7. PERFORMING ORGANIZATION NAME( S ) AND ADDRESS(ES) North Carolina State University,Department of...Electrical and Computer Engineering,Raleigh,NC,27695 8. PERFORMING ORGANIZATION REPORT NUMBER 9. SPONSORING/MONITORING AGENCY NAME( S ) AND ADDRESS(ES) 10

  6. The telecommunications and data acquisition progress report 42-64

    NASA Technical Reports Server (NTRS)

    Renzetti, N. A. (Editor)

    1981-01-01

    Progress in the development and operations of the Deep Space Network is reported. Developments in Earth-based radio technology as applied to geodynamics, astrophysics, and the radio search for extraterrestrial intelligence are included.

  7. The telecommunications and data acquisition

    NASA Technical Reports Server (NTRS)

    Renzetti, N. A. (Editor)

    1980-01-01

    Radio astronomy and radio interferometry at microwave frequencies are discussed. Other topics concerning the Deep Space Network include program planning, planetary and interplanetary mission support, tracking and ground based navigation, communications, and station control and system technology.

  8. Optimizing the African VLBI Network for Astronomy and Geodesy

    NASA Astrophysics Data System (ADS)

    de Witt, A.; Mayer, D.; MacLeod, G.; Combrinck, L.; Petrov, L.; Nickola, M.

    2016-12-01

    The African VLBI Network will be a pan-African network of radio telescopes comprised of converted redundant satellite Earth-station antennas and new purpose-built radio telescopes. The first of these antennas, in Ghana, is currently being converted to a radio telescope and current funding is estimated to permit the conversion of two more antennas in Africa. These antennas will initially be equipped with a 5-GHz and 6.7-GHz receiver and the next receiver likely to be fitted is a 1.4-1.7-GHz receiver. While it would be advantageous for the AVN antennas to be able to participate also in geodetic and astrometric VLBI observations, there is no funding currently for this. In this paper we re-visit the scientific justifications for the AVN in an attempt to optimize the AVN for each science case, both astronomical and geodetic.

  9. Game theoretic wireless resource allocation for H.264 MGS video transmission over cognitive radio networks

    NASA Astrophysics Data System (ADS)

    Fragkoulis, Alexandros; Kondi, Lisimachos P.; Parsopoulos, Konstantinos E.

    2015-03-01

    We propose a method for the fair and efficient allocation of wireless resources over a cognitive radio system network to transmit multiple scalable video streams to multiple users. The method exploits the dynamic architecture of the Scalable Video Coding extension of the H.264 standard, along with the diversity that OFDMA networks provide. We use a game-theoretic Nash Bargaining Solution (NBS) framework to ensure that each user receives the minimum video quality requirements, while maintaining fairness over the cognitive radio system. An optimization problem is formulated, where the objective is the maximization of the Nash product while minimizing the waste of resources. The problem is solved by using a Swarm Intelligence optimizer, namely Particle Swarm Optimization. Due to the high dimensionality of the problem, we also introduce a dimension-reduction technique. Our experimental results demonstrate the fairness imposed by the employed NBS framework.

  10. Impact of in-band interference on a wake-up radio system in wireless sensor networks

    NASA Astrophysics Data System (ADS)

    Lebreton, J. M.; Murad, N. M.; Lorion, R.

    2017-05-01

    The energy efficiency of Wireless Sensor Networks (WSNs) is considerably improved with Wake-up Radio (WuR) systems. However, their resilience to interference is often neglected in the literature. This might be an issue due to the proliferation of wireless devices and the growing field of internet of things. In this paper, we evaluate the impact of in-band interference from wireless devices on a WuR system. The approach proves that WuR systems are still performing well when coexisting with external wireless networks, even if the energy-efficiency is slightly reduced.

  11. A Survey on Node Clustering in Cognitive Radio Wireless Sensor Networks.

    PubMed

    Joshi, Gyanendra Prasad; Kim, Sung Won

    2016-09-10

    Cognitive radio wireless sensor networks (CR-WSNs) have attracted a great deal of attention recently due to the emerging spectrum scarcity issue. This work attempts to provide a detailed analysis of the role of node clustering in CR-WSNs. We outline the objectives, requirements, and advantages of node clustering in CR-WSNs. We describe how a CR-WSN with node clustering differs from conventional wireless sensor networks, and we discuss its characteristics, architecture, and topologies. We survey the existing clustering algorithms and compare their objectives and features. We suggest how clustering issues and challenges can be handled.

  12. Space Weather Services of Korea

    NASA Astrophysics Data System (ADS)

    Yoon, K.; Hong, S.; Park, S.; Kim, Y. Y.; Wi, G.

    2015-12-01

    The Korean Space Weather Center (KSWC) of the National Radio Research Agency (RRA) is a government agency which is the official source of space weather information for Korean Government and the primary action agency of emergency measure to severe space weather condition. KSWC's main role is providing alerts, watches, and forecasts in order to minimize the space weather impacts on both of public and commercial sectors of satellites, aviation, communications, navigations, power grids, and etc. KSWC is also in charge of monitoring the space weather condition and conducting research and development for its main role of space weather operation in Korea. In this study, we will present KSWC's recent efforts on development of application-oriented space weather research products and services on user needs, and introduce new international collaborative projects, such as IPS-Driven Enlil model, global network of DSCOVR and STEREO satellites tracking, and ARMAS (Automated Radiation Measurement for Aviation Safety).

  13. Space Weather Services of Korea

    NASA Astrophysics Data System (ADS)

    Yoon, KiChang; Kim, Jae-Hun; Kim, Young Yun; Kwon, Yongki; Wi, Gwan-sik

    2016-07-01

    The Korean Space Weather Center (KSWC) of the National Radio Research Agency (RRA) is a government agency which is the official source of space weather information for Korean Government and the primary action agency of emergency measure to severe space weather condition. KSWC's main role is providing alerts, watches, and forecasts in order to minimize the space weather impacts on both of public and commercial sectors of satellites, aviation, communications, navigations, power grids, and etc. KSWC is also in charge of monitoring the space weather condition and conducting research and development for its main role of space weather operation in Korea. In this study, we will present KSWC's recent efforts on development of application-oriented space weather research products and services on user needs, and introduce new international collaborative projects, such as IPS-Driven Enlil model, DREAM model estimating electron in satellite orbit, global network of DSCOVR and STEREO satellites tracking, and ARMAS (Automated Radiation Measurement for Aviation Safety).

  14. Space Weather Services of Korea

    NASA Astrophysics Data System (ADS)

    Yoon, K.; Hong, S.; Jangsuk, C.; Dong Kyu, K.; Jinyee, C.; Yeongoh, C.

    2016-12-01

    The Korean Space Weather Center (KSWC) of the National Radio Research Agency (RRA) is a government agency which is the official source of space weather information for Korean Government and the primary action agency of emergency measure to severe space weather condition. KSWC's main role is providing alerts, watches, and forecasts in order to minimize the space weather impacts on both of public and commercial sectors of satellites, aviation, communications, navigations, power grids, and etc. KSWC is also in charge of monitoring the space weather condition and conducting research and development for its main role of space weather operation in Korea. In this study, we will present KSWC's recent efforts on development of application-oriented space weather research products and services on user needs, and introduce new international collaborative projects, such as IPS-Driven Enlil model, DREAM model estimating electron in satellite orbit, global network of DSCOVR and STEREO satellites tracking, and ARMAS (Automated Radiation Measurement for Aviation Safety).

  15. Dynamic robustness of knowledge collaboration network of open source product development community

    NASA Astrophysics Data System (ADS)

    Zhou, Hong-Li; Zhang, Xiao-Dong

    2018-01-01

    As an emergent innovative design style, open source product development communities are characterized by a self-organizing, mass collaborative, networked structure. The robustness of the community is critical to its performance. Using the complex network modeling method, the knowledge collaboration network of the community is formulated, and the robustness of the network is systematically and dynamically studied. The characteristics of the network along the development period determine that its robustness should be studied from three time stages: the start-up, development and mature stages of the network. Five kinds of user-loss pattern are designed, to assess the network's robustness under different situations in each of these three time stages. Two indexes - the largest connected component and the network efficiency - are used to evaluate the robustness of the community. The proposed approach is applied in an existing open source car design community. The results indicate that the knowledge collaboration networks show different levels of robustness in different stages and different user loss patterns. Such analysis can be applied to provide protection strategies for the key users involved in knowledge dissemination and knowledge contribution at different stages of the network, thereby promoting the sustainable and stable development of the open source community.

  16. Exploiting Publication Contents and Collaboration Networks for Collaborator Recommendation

    PubMed Central

    Kong, Xiangjie; Jiang, Huizhen; Yang, Zhuo; Xu, Zhenzhen; Xia, Feng; Tolba, Amr

    2016-01-01

    Thanks to the proliferation of online social networks, it has become conventional for researchers to communicate and collaborate with each other. Meanwhile, one critical challenge arises, that is, how to find the most relevant and potential collaborators for each researcher? In this work, we propose a novel collaborator recommendation model called CCRec, which combines the information on researchers’ publications and collaboration network to generate better recommendation. In order to effectively identify the most potential collaborators for researchers, we adopt a topic clustering model to identify the academic domains, as well as a random walk model to compute researchers’ feature vectors. Using DBLP datasets, we conduct benchmarking experiments to examine the performance of CCRec. The experimental results show that CCRec outperforms other state-of-the-art methods in terms of precision, recall and F1 score. PMID:26849682

  17. Markov Task Network: A Framework for Service Composition under Uncertainty in Cyber-Physical Systems.

    PubMed

    Mohammed, Abdul-Wahid; Xu, Yang; Hu, Haixiao; Agyemang, Brighter

    2016-09-21

    In novel collaborative systems, cooperative entities collaborate services to achieve local and global objectives. With the growing pervasiveness of cyber-physical systems, however, such collaboration is hampered by differences in the operations of the cyber and physical objects, and the need for the dynamic formation of collaborative functionality given high-level system goals has become practical. In this paper, we propose a cross-layer automation and management model for cyber-physical systems. This models the dynamic formation of collaborative services pursuing laid-down system goals as an ontology-oriented hierarchical task network. Ontological intelligence provides the semantic technology of this model, and through semantic reasoning, primitive tasks can be dynamically composed from high-level system goals. In dealing with uncertainty, we further propose a novel bridge between hierarchical task networks and Markov logic networks, called the Markov task network. This leverages the efficient inference algorithms of Markov logic networks to reduce both computational and inferential loads in task decomposition. From the results of our experiments, high-precision service composition under uncertainty can be achieved using this approach.

  18. How does investment in research training affect the development of research networks and collaborations?

    PubMed

    Paina, Ligia; Ssengooba, Freddie; Waswa, Douglas; M'imunya, James M; Bennett, Sara

    2013-05-20

    Whether and how research training programs contribute to research network development is underexplored. The Fogarty International Center (FIC) has supported overseas research training programs for over two decades. FIC programs could provide an entry point in the development of research networks and collaborations. We examine whether FIC's investment in research training contributed to the development of networks and collaborations in two countries with longstanding FIC investments - Uganda and Kenya - and the factors which facilitated this process. As part of two case studies at Uganda's Makerere University and Kenya's University of Nairobi, we conducted 53 semi-structured in-depth interviews and nine focus group discussions. To expand on our case study findings, we conducted a focused bibliometric analysis on two purposively selected topic areas to examine scientific productivity and used online network illustration tools to examine the resulting network structures. FIC support made important contributions to network development. Respondents from both Uganda and Kenya confirmed that FIC programs consistently provided trainees with networking skills and exposure to research collaborations, primarily within the institutions implementing FIC programs. In both countries, networks struggled with inclusiveness, particularly in HIV/AIDS research. Ugandan respondents perceived their networks to be more cohesive than Kenyan respondents did. Network cohesiveness was positively correlated with the magnitude and longevity of FIC's programs. Support from FIC grants to local and regional research network development and networking opportunities, such as conferences, was rare. Synergies between FIC programs and research grants helped to solidify and maintain research collaborations. Networks developed where FIC's programs focused on a particular institution, there was a critical mass of trainees with similar interests, and investments for network development were available from early implementation. Networks were less likely to emerge where FIC efforts were thinly scattered across multiple institutions. The availability of complementary research grants created opportunities for researchers to collaborate in grant writing, research implementation, and publications. FIC experiences in Uganda and Kenya showcase the important role of research training programs in creating and sustaining research networks. FIC programs should consider including support to research networks more systematically in their capacity development agenda.

  19. Team assembly mechanisms determine collaboration network structure and team performance.

    PubMed

    Guimerà, Roger; Uzzi, Brian; Spiro, Jarrett; Amaral, Luís A Nunes

    2005-04-29

    Agents in creative enterprises are embedded in networks that inspire, support, and evaluate their work. Here, we investigate how the mechanisms by which creative teams self-assemble determine the structure of these collaboration networks. We propose a model for the self-assembly of creative teams that has its basis in three parameters: team size, the fraction of newcomers in new productions, and the tendency of incumbents to repeat previous collaborations. The model suggests that the emergence of a large connected community of practitioners can be described as a phase transition. We find that team assembly mechanisms determine both the structure of the collaboration network and team performance for teams derived from both artistic and scientific fields.

  20. Self-organizing feature maps for dynamic control of radio resources in CDMA microcellular networks

    NASA Astrophysics Data System (ADS)

    Hortos, William S.

    1998-03-01

    The application of artificial neural networks to the channel assignment problem for cellular code-division multiple access (CDMA) cellular networks has previously been investigated. CDMA takes advantage of voice activity and spatial isolation because its capacity is only interference limited, unlike time-division multiple access (TDMA) and frequency-division multiple access (FDMA) where capacities are bandwidth-limited. Any reduction in interference in CDMA translates linearly into increased capacity. To satisfy the high demands for new services and improved connectivity for mobile communications, microcellular and picocellular systems are being introduced. For these systems, there is a need to develop robust and efficient management procedures for the allocation of power and spectrum to maximize radio capacity. Topology-conserving mappings play an important role in the biological processing of sensory inputs. The same principles underlying Kohonen's self-organizing feature maps (SOFMs) are applied to the adaptive control of radio resources to minimize interference, hence, maximize capacity in direct-sequence (DS) CDMA networks. The approach based on SOFMs is applied to some published examples of both theoretical and empirical models of DS/CDMA microcellular networks in metropolitan areas. The results of the approach for these examples are informally compared to the performance of algorithms, based on Hopfield- Tank neural networks and on genetic algorithms, for the channel assignment problem.

  1. Fragmented Romanian sociology: growth and structure of the collaboration network.

    PubMed

    Hâncean, Marian-Gabriel; Perc, Matjaž; Vlăsceanu, Lazăr

    2014-01-01

    Structural patterns in collaboration networks are essential for understanding how new ideas, research practices, innovation or cooperation circulate and develop within academic communities and between and within university departments. In our research, we explore and investigate the structure of the collaboration network formed by the academics working full-time within all the 17 sociology departments across Romania. We show that the collaboration network is sparse and fragmented, and that it constitutes an environment that does not promote the circulation of new ideas and innovation within the field. Although recent years have witnessed an increase in the productivity of Romanian sociologists, there is still ample room for improvement in terms of the interaction infrastructure that ought to link individuals together so that they could maximize their potentials. We also fail to discern evidence in favor of the Matthew effect governing the growth of the network, which suggests scientific success and productivity are not rewarded. Instead, the structural properties of the collaboration network are partly those of a core-periphery network, where the spread of innovation and change can be explained by structural equivalence rather than by interpersonal influence models. We also provide support for the idea that, within the observed network, collaboration is the product of homophily rather than prestige effects. Further research on the subject based on data from other countries in the region is needed to place our results in a comparative framework, in particular to discern whether the behavior of the Romanian sociologist community is unique or rather common.

  2. Fragmented Romanian Sociology: Growth and Structure of the Collaboration Network

    PubMed Central

    Hâncean, Marian-Gabriel; Perc, Matjaž; Vlăsceanu, Lazăr

    2014-01-01

    Structural patterns in collaboration networks are essential for understanding how new ideas, research practices, innovation or cooperation circulate and develop within academic communities and between and within university departments. In our research, we explore and investigate the structure of the collaboration network formed by the academics working full-time within all the 17 sociology departments across Romania. We show that the collaboration network is sparse and fragmented, and that it constitutes an environment that does not promote the circulation of new ideas and innovation within the field. Although recent years have witnessed an increase in the productivity of Romanian sociologists, there is still ample room for improvement in terms of the interaction infrastructure that ought to link individuals together so that they could maximize their potentials. We also fail to discern evidence in favor of the Matthew effect governing the growth of the network, which suggests scientific success and productivity are not rewarded. Instead, the structural properties of the collaboration network are partly those of a core-periphery network, where the spread of innovation and change can be explained by structural equivalence rather than by interpersonal influence models. We also provide support for the idea that, within the observed network, collaboration is the product of homophily rather than prestige effects. Further research on the subject based on data from other countries in the region is needed to place our results in a comparative framework, in particular to discern whether the behavior of the Romanian sociologist community is unique or rather common. PMID:25409180

  3. Design and Implementation of an Underlay Control Channel for Cognitive Radios

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Daryl Wasden; Hussein Moradi; Behrouz Farhang-Boroujeny

    Implementation of any cognitive radio network requires an effective control channel that can operate under various modes of activity from the primary users. This paper reports the design and implementation of a filter bank multicarrier spread spectrum (FBMC-SS) system for use as the control channel in cognitive radio networks. The proposed design is based on a filtered multitone (FMT) implementation. Carrier and timing acquisition and tracking methods as well as a blind channel estimation method are developed for the proposed control channel. We also report an implementation of the proposed FBMC-SS system on a hardware platform; a FlexRIO FPGA modulemore » from National Instruments.« less

  4. Case Study: Using The OMG SWRADIO Profile and SDR Forum Input for NASA's Space Telecommunications Radio System

    NASA Technical Reports Server (NTRS)

    Briones, Janette C.; Handler, Louis M.; Hall, Steve C.; Reinhart, Richard C.; Kacpura, Thomas J.

    2009-01-01

    The Space Telecommunication Radio System (STRS) standard is a Software Defined Radio (SDR) architecture standard developed by NASA. The goal of STRS is to reduce NASA s dependence on custom, proprietary architectures with unique and varying interfaces and hardware and support reuse of waveforms across platforms. The STRS project worked with members of the Object Management Group (OMG), Software Defined Radio Forum, and industry partners to leverage existing standards and knowledge. This collaboration included investigating the use of the OMG s Platform-Independent Model (PIM) SWRadio as the basis for an STRS PIM. This paper details the influence of the OMG technologies on the STRS update effort, findings in the STRS/SWRadio mapping, and provides a summary of the SDR Forum recommendations.

  5. Intelligent Mobile Technologies

    NASA Technical Reports Server (NTRS)

    Alena, Rick; Gilbaugh, Bruce; Glass, Brian; Swanson, Keith (Technical Monitor)

    2000-01-01

    Testing involves commercial radio equipment approved for export and use in Canada. Testing was conducted in the Canadian High Arctic, where hilly terrain provided the worst-case testing. SFU and Canadian governmental agencies made significant technical contributions. The only technical data related to radio testing was exchanged with SFU. Test protocols are standard radio tests performed by communication technicians worldwide. The Joint Fields Operations objectives included the following: (1) to provide Internet communications services for field science work and mobile exploration systems; (2) to evaluate the range and throughput of three different medium-range radio link technologies for providing coverage of the crater area; and (3) to demonstrate collaborative software such as NetMeeting with multi-point video for exchange of scientific information between remote node and base-base camp and science centers as part of communications testing.

  6. Do learning collaboratives strengthen communication? A comparison of organizational team communication networks over time.

    PubMed

    Bunger, Alicia C; Lengnick-Hall, Rebecca

    Collaborative learning models were designed to support quality improvements, such as innovation implementation by promoting communication within organizational teams. Yet the effect of collaborative learning approaches on organizational team communication during implementation is untested. The aim of this study was to explore change in communication patterns within teams from children's mental health organizations during a year-long learning collaborative focused on implementing a new treatment. We adopt a social network perspective to examine intraorganizational communication within each team and assess change in (a) the frequency of communication among team members, (b) communication across organizational hierarchies, and (c) the overall structure of team communication networks. A pretest-posttest design compared communication among 135 participants from 21 organizational teams at the start and end of a learning collaborative. At both time points, participants were asked to list the members of their team and rate the frequency of communication with each along a 7-point Likert scale. Several individual, pair-wise, and team level communication network metrics were calculated and compared over time. At the individual level, participants reported communicating with more team members by the end of the learning collaborative. Cross-hierarchical communication did not change. At the team level, these changes manifested differently depending on team size. In large teams, communication frequency increased, and networks grew denser and slightly less centralized. In small teams, communication frequency declined, growing more sparse and centralized. Results suggest that team communication patterns change minimally but evolve differently depending on size. Learning collaboratives may be more helpful for enhancing communication among larger teams; thus, managers might consider selecting and sending larger staff teams to learning collaboratives. This study highlights key future research directions that can disentangle the relationship between learning collaboratives and team networks.

  7. Breaking Free with Wireless Networks.

    ERIC Educational Resources Information Center

    Fleischman, John

    2002-01-01

    Discusses wireless local area networks (LANs) which typically consist of laptop computers that connect to fixed access points via infrared or radio signals. Topics include wide area networks; personal area networks; problems, including limitations of available bandwidth, interference, and security concerns; use in education; interoperability;…

  8. Cluster based architecture and network maintenance protocol for medical priority aware cognitive radio based hospital.

    PubMed

    Al Mamoon, Ishtiak; Muzahidul Islam, A K M; Baharun, Sabariah; Ahmed, Ashir; Komaki, Shozo

    2016-08-01

    Due to the rapid growth of wireless medical devices in near future, wireless healthcare services may face some inescapable issue such as medical spectrum scarcity, electromagnetic interference (EMI), bandwidth constraint, security and finally medical data communication model. To mitigate these issues, cognitive radio (CR) or opportunistic radio network enabled wireless technology is suitable for the upcoming wireless healthcare system. The up-to-date research on CR based healthcare has exposed some developments on EMI and spectrum problems. However, the investigation recommendation on system design and network model for CR enabled hospital is rare. Thus, this research designs a hierarchy based hybrid network architecture and network maintenance protocols for previously proposed CR hospital system, known as CogMed. In the previous study, the detail architecture of CogMed and its maintenance protocols were not present. The proposed architecture includes clustering concepts for cognitive base stations and non-medical devices. Two cluster head (CH selector equations are formulated based on priority of location, device, mobility rate of devices and number of accessible channels. In order to maintain the integrity of the proposed network model, node joining and node leaving protocols are also proposed. Finally, the simulation results show that the proposed network maintenance time is very low for emergency medical devices (average maintenance period 9.5 ms) and the re-clustering effects for different mobility enabled non-medical devices are also balanced.

  9. Web-based Teaching Radio Interferometer for Africa

    NASA Astrophysics Data System (ADS)

    Carignan, Claude; Libert, Yannick

    2016-10-01

    This presentation describes the web-based Teaching Radio Interferometer being built on the campus of the University of Cape Town, in South Africa, to train the future users of the African VLBI (Very Long Baseline Interferometry) Network (AVN).

  10. DSMS science operations concept

    NASA Technical Reports Server (NTRS)

    Connally, M. J.; Kuiper, T. B.

    2001-01-01

    The Deep Space Mission System (DSMS) Science Operations Concept describes the vision for enabling the use of the DSMS, particularly the Deep Space Network (DSN) for direct science observations in the areas of radio astronomy, planetary radar, radio science and VLBI.

  11. Deep Space Network capabilities for receiving weak probe signals

    NASA Technical Reports Server (NTRS)

    Asmar, Sami; Johnston, Doug; Preston, Robert

    2004-01-01

    This paper will describe the capability and highlight the cases of the critical communications for the Mars rovers and Saturn Orbit Insertion and preparation radio tracking of the Huygens probe at (non-DSN) radio telescopes.

  12. The Last Millimeter: Interfacing the New Public Radio Satellite System. Info. Packets No. 14.

    ERIC Educational Resources Information Center

    Pizzi, Skip

    Public radio is about to achieve a new technological level as the new Public Radio Satellite System (PRSS) is deployed. The network will dramatically improve the capacity and quality of its interconnection system, but proper interfacing at member stations will be required to realize the full benefits of the new system. The new system uses digital…

  13. Integration of power over fiber on RoF systems in different scenarios

    NASA Astrophysics Data System (ADS)

    Vázquez, C.; Montero, D. S.; Pinzón, P. J.; López-Cardona, J. D.; Contreras, P.; Tapetado, A.

    2017-01-01

    Future high capacity of the 5th Generation radio environment will boost transport networks to be adapted. The high bandwidth, together with stringent delay and jitter requirements, make dedicated optical connectivity a preferred solution for fronthaul. Those Radio Access Networks apart from higher capacity and lower latency should have higher energy efficiency. In order to cover this aspect, power over fiber has been pointed out as a key technology for that purpose having in mind that control plane will be centralized on future Cloud RAN and that sometimes Remote Radio Heads should be deployed in places lacking external power supply in order to fulfill the desired coverage. In this paper, different scenarios on potential demanding environments of power over fiber on Radio over Fiber systems such as automotive, in-house and remote mobile fronthaul will be discussed. Some tests on power over fiber systems based on different optical fibers are provided.

  14. Radio Occultation Experiments with Venus Express and Mars Express using the Planetary Radio Interferometry and Doppler Experiment (PRIDE) Technique

    NASA Astrophysics Data System (ADS)

    Bocanegra Bahamon, T.; Gurvits, L.; Molera Calves, G.; Cimo, G.; Duev, D.; Pogrebenko, S.; Dirkx, D.; Rosenblatt, P.

    2017-12-01

    The Planetary Radio Interferometry and Doppler Experiment (PRIDE) is a technique that can be used to enhance multiple radio science experiments of planetary missions. By 'eavesdropping' on the spacecraft signal using radio telescopes from different VLBI networks around the world, the PRIDE technique provides precise open-loop Doppler and VLBI observables to able to reconstruct the spacecraft's orbit. The application of this technique for atmospheric studies has been assessed by observing ESA's Venus Express (VEX) and Mars Express (MEX) during multiple Venus and Mars occultation events between 2012 and 2014. From these observing sessions density, temperature and pressure profiles of Venus and Mars neutral atmosphere and ionosphere have been retrieved. We present an error propagation analysis where the uncertainties of the atmospheric properties measured with this technique have been derived. These activities serve as demonstration of the applicability of the PRIDE technique for radio occultation studies, and provides a benchmark against the traditional Doppler tracking provided by the NASA's DSN and ESA's Estrack networks for these same purposes, in the framework of the upcoming ESA JUICE mission to the Jovian system.

  15. Linking behavior in the physics education research coauthorship network

    NASA Astrophysics Data System (ADS)

    Anderson, Katharine A.; Crespi, Matthew; Sayre, Eleanor C.

    2017-06-01

    There is considerable long-term interest in understanding the dynamics of collaboration networks, and how these networks form and evolve over time. Most of the work done on the dynamics of social networks focuses on well-established communities. Work examining emerging social networks is rarer, simply because data are difficult to obtain in real time. In this paper, we use thirty years of data from an emerging scientific community to look at that crucial early stage in the development of a social network. We show that when the field was very young, islands of individual researchers labored in relative isolation, and the coauthorship network was disconnected. Thirty years later, rather than a cluster of individuals, we find a true collaborative community, bound together by a robust collaboration network. However, this change did not take place gradually—the network remained a loose assortment of isolated individuals until the mid 2000s, when those smaller parts suddenly knit themselves together into a single whole. In the rest of this paper, we consider the role of three factors in these observed structural changes: growth, changes in social norms, and the introduction of institutions such as field-specific conferences and journals. We have data from the very earliest years of the field, a period which includes the introduction of two different institutions: the first field-specific conference, and the first field-specific journals. We also identify two relevant behavioral shifts: a discrete increase in coauthorship coincident with the first conference, and a shift among established authors away from collaborating with outsiders, towards collaborating with each other. The interaction of these factors gives us insight into the formation of collaboration networks more broadly.

  16. Toward Collaboration Sensing

    ERIC Educational Resources Information Center

    Schneider, Bertrand; Pea, Roy

    2014-01-01

    We describe preliminary applications of network analysis techniques to eye-tracking data collected during a collaborative learning activity. This paper makes three contributions: first, we visualize collaborative eye-tracking data as networks, where the nodes of the graph represent fixations and edges represent saccades. We found that those…

  17. The importance of national and international collaboration in adult congenital heart disease: A network analysis of research output.

    PubMed

    Orwat, Melanie Iris; Kempny, Aleksander; Bauer, Ulrike; Gatzoulis, Michael A; Baumgartner, Helmut; Diller, Gerhard-Paul

    2015-09-15

    The determinants of adult congenital heart disease (ACHD) research output are only partially understood. The heterogeneity of ACHD naturally calls for collaborative work; however, limited information exists on the impact of collaboration on academic performance. We aimed to examine the global topology of ACHD research, distribution of research collaboration and its association with cumulative research output. Based on publications presenting original research between 2005 and 2011, a network analysis was performed quantifying centrality measures and key players in the field of ACHD. In addition, network maps were produced to illustrate the global distribution and interconnected nature of ACHD research. The proportion of collaborative research was 35.6 % overall, with a wide variation between countries (7.1 to 62.8%). The degree of research collaboration, as well as measures of network centrality (betweenness and degree centrality), were statistically associated with cumulative research output independently of national wealth and available workforce. The global ACHD research network was found to be scale-free with a small number of central hubs and a relatively large number of peripheral nodes. In addition, we could identify potentially influential hubs based on cluster analysis and measures of centrality/key player analysis. Using network analysis methods the current study illustrates the complex and global structures of ACHD research. It suggests that collaboration between research institutions is associated with higher academic output. As a consequence national and international collaboration in ACHD research should be encouraged and the creation of an adequate supporting infrastructure should be further promoted. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

  18. Do project management and network governance contribute to inter-organisational collaboration in primary care? A mixed methods study.

    PubMed

    Schepman, Sanneke; Valentijn, Pim; Bruijnzeels, Marc; Maaijen, Marlies; de Bakker, Dinny; Batenburg, Ronald; de Bont, Antoinette

    2018-06-07

    The need for organisational development in primary care has increased as it is accepted as a means of curbing rising costs and responding to demographic transitions. It is only within such inter-organisational networks that small-scale practices can offer treatment to complex patients and continuity of care. The aim of this paper is to explore, through the experience of professionals and patients, whether, and how, project management and network governance can improve the outcomes of projects which promote inter-organisational collaboration in primary care. This paper describes a study of projects aimed at improving inter-organisational collaboration in Dutch primary care. The projects' success in project management and network governance was monitored by interviewing project leaders and board members on the one hand, and improvement in the collaboration by surveying professionals and patients on the other. Both qualitative and quantitative methods were applied to assess the projects. These were analysed, finally, using multi-level models in order to account for the variation in the projects, professionals and patients. Successful network governance was associated positively with the professionals' satisfaction with the collaboration; but not with improvements in the quality of care as experienced by patients. Neither patients nor professionals perceived successful project management as associated with the outcomes of the collaboration projects. This study shows that network governance in particular makes a difference to the outcomes of inter-organisational collaboration in primary care. However, project management is not a predictor for successful inter-organisational collaboration in primary care.

  19. Celestial data routing network

    NASA Astrophysics Data System (ADS)

    Bordetsky, Alex

    2000-11-01

    Imagine that information processing human-machine network is threatened in a particular part of the world. Suppose that an anticipated threat of physical attacks could lead to disruption of telecommunications network management infrastructure and access capabilities for small geographically distributed groups engaged in collaborative operations. Suppose that small group of astronauts are exploring the solar planet and need to quickly configure orbital information network to support their collaborative work and local communications. The critical need in both scenarios would be a set of low-cost means of small team celestial networking. To the geographically distributed mobile collaborating groups such means would allow to maintain collaborative multipoint work, set up orbital local area network, and provide orbital intranet communications. This would be accomplished by dynamically assembling the network enabling infrastructure of the small satellite based router, satellite based Codec, and set of satellite based intelligent management agents. Cooperating single function pico satellites, acting as agents and personal switching devices together would represent self-organizing intelligent orbital network of cooperating mobile management nodes. Cooperative behavior of the pico satellite based agents would be achieved by comprising a small orbital artificial neural network capable of learning and restructing the networking resources in response to the anticipated threat.

  20. Device-Free Localization via an Extreme Learning Machine with Parameterized Geometrical Feature Extraction.

    PubMed

    Zhang, Jie; Xiao, Wendong; Zhang, Sen; Huang, Shoudong

    2017-04-17

    Device-free localization (DFL) is becoming one of the new technologies in wireless localization field, due to its advantage that the target to be localized does not need to be attached to any electronic device. In the radio-frequency (RF) DFL system, radio transmitters (RTs) and radio receivers (RXs) are used to sense the target collaboratively, and the location of the target can be estimated by fusing the changes of the received signal strength (RSS) measurements associated with the wireless links. In this paper, we will propose an extreme learning machine (ELM) approach for DFL, to improve the efficiency and the accuracy of the localization algorithm. Different from the conventional machine learning approaches for wireless localization, in which the above differential RSS measurements are trivially used as the only input features, we introduce the parameterized geometrical representation for an affected link, which consists of its geometrical intercepts and differential RSS measurement. Parameterized geometrical feature extraction (PGFE) is performed for the affected links and the features are used as the inputs of ELM. The proposed PGFE-ELM for DFL is trained in the offline phase and performed for real-time localization in the online phase, where the estimated location of the target is obtained through the created ELM. PGFE-ELM has the advantages that the affected links used by ELM in the online phase can be different from those used for training in the offline phase, and can be more robust to deal with the uncertain combination of the detectable wireless links. Experimental results show that the proposed PGFE-ELM can improve the localization accuracy and learning speed significantly compared with a number of the existing machine learning and DFL approaches, including the weighted K-nearest neighbor (WKNN), support vector machine (SVM), back propagation neural network (BPNN), as well as the well-known radio tomographic imaging (RTI) DFL approach.

  1. Device-Free Localization via an Extreme Learning Machine with Parameterized Geometrical Feature Extraction

    PubMed Central

    Zhang, Jie; Xiao, Wendong; Zhang, Sen; Huang, Shoudong

    2017-01-01

    Device-free localization (DFL) is becoming one of the new technologies in wireless localization field, due to its advantage that the target to be localized does not need to be attached to any electronic device. In the radio-frequency (RF) DFL system, radio transmitters (RTs) and radio receivers (RXs) are used to sense the target collaboratively, and the location of the target can be estimated by fusing the changes of the received signal strength (RSS) measurements associated with the wireless links. In this paper, we will propose an extreme learning machine (ELM) approach for DFL, to improve the efficiency and the accuracy of the localization algorithm. Different from the conventional machine learning approaches for wireless localization, in which the above differential RSS measurements are trivially used as the only input features, we introduce the parameterized geometrical representation for an affected link, which consists of its geometrical intercepts and differential RSS measurement. Parameterized geometrical feature extraction (PGFE) is performed for the affected links and the features are used as the inputs of ELM. The proposed PGFE-ELM for DFL is trained in the offline phase and performed for real-time localization in the online phase, where the estimated location of the target is obtained through the created ELM. PGFE-ELM has the advantages that the affected links used by ELM in the online phase can be different from those used for training in the offline phase, and can be more robust to deal with the uncertain combination of the detectable wireless links. Experimental results show that the proposed PGFE-ELM can improve the localization accuracy and learning speed significantly compared with a number of the existing machine learning and DFL approaches, including the weighted K-nearest neighbor (WKNN), support vector machine (SVM), back propagation neural network (BPNN), as well as the well-known radio tomographic imaging (RTI) DFL approach. PMID:28420187

  2. A study on haptic collaborative game in shared virtual environment

    NASA Astrophysics Data System (ADS)

    Lu, Keke; Liu, Guanyang; Liu, Lingzhi

    2013-03-01

    A study on collaborative game in shared virtual environment with haptic feedback over computer networks is introduced in this paper. A collaborative task was used where the players located at remote sites and played the game together. The player can feel visual and haptic feedback in virtual environment compared to traditional networked multiplayer games. The experiment was desired in two conditions: visual feedback only and visual-haptic feedback. The goal of the experiment is to assess the impact of force feedback on collaborative task performance. Results indicate that haptic feedback is beneficial for performance enhancement for collaborative game in shared virtual environment. The outcomes of this research can have a powerful impact on the networked computer games.

  3. Radio Interoperability: Addressing the Real Reasons We Don’t Communicate Well During Emergencies

    DTIC Science & Technology

    2006-03-01

    remoteness or traffic load on the network , and dead batteries. Public safety first responders experience many of the same things as they use their radio...provider may hold thousands of frequency licenses nationwide, but deploys only a handful at each tower site . The limitation of the phone network to handle...support players off- site (still responding , or at alternate locations, such as Emergency Operations Centers). 9. Listening to recordings after an

  4. The C2 Workstation and Data Replication over Disadvantaged Tactical Communication Links

    DTIC Science & Technology

    2007-09-01

    person shall be subject to a penalty for failing to comply with a collection of information if it does not display a currently valid OMB control number...SECURITY CLASSIFICATION OF: 17. LIMITATION OF ABSTRACT UU 18. NUMBER OF PAGES 14 19a. NAME OF RESPONSIBLE PERSON a. REPORT unclassified b...PUBLIC RELEASE C2WS Physical Environment Zodiac Network Radio Network Combat Level Node (Vehicle) Radio Local Store Local Store Local Store To Other

  5. Design of a Covert RFID Tag Network for Target Discovery and Target Information Routing

    PubMed Central

    Pan, Qihe; Narayanan, Ram M.

    2011-01-01

    Radio frequency identification (RFID) tags are small electronic devices working in the radio frequency range. They use wireless radio communications to automatically identify objects or people without the need for line-of-sight or contact, and are widely used in inventory tracking, object location, environmental monitoring. This paper presents a design of a covert RFID tag network for target discovery and target information routing. In the design, a static or very slowly moving target in the field of RFID tags transmits a distinct pseudo-noise signal, and the RFID tags in the network collect the target information and route it to the command center. A map of each RFID tag’s location is saved at command center, which can determine where a RFID tag is located based on each RFID tag’s ID. We propose the target information collection method with target association and clustering, and we also propose the information routing algorithm within the RFID tag network. The design and operation of the proposed algorithms are illustrated through examples. Simulation results demonstrate the effectiveness of the design. PMID:22163693

  6. Design of a covert RFID tag network for target discovery and target information routing.

    PubMed

    Pan, Qihe; Narayanan, Ram M

    2011-01-01

    Radio frequency identification (RFID) tags are small electronic devices working in the radio frequency range. They use wireless radio communications to automatically identify objects or people without the need for line-of-sight or contact, and are widely used in inventory tracking, object location, environmental monitoring. This paper presents a design of a covert RFID tag network for target discovery and target information routing. In the design, a static or very slowly moving target in the field of RFID tags transmits a distinct pseudo-noise signal, and the RFID tags in the network collect the target information and route it to the command center. A map of each RFID tag's location is saved at command center, which can determine where a RFID tag is located based on each RFID tag's ID. We propose the target information collection method with target association and clustering, and we also propose the information routing algorithm within the RFID tag network. The design and operation of the proposed algorithms are illustrated through examples. Simulation results demonstrate the effectiveness of the design.

  7. Flexible communications for battlespace 2000

    NASA Astrophysics Data System (ADS)

    Seiler, Thomas M.

    2000-08-01

    The advent of software-defined radios (products of DSP) with embedded processors capable of performing, communications functions (i.e., modulation) makes it possible for networks of radios to operate efficiently by changing its transmission characteristics (waveform) to fit the input data bandwidth requirements commensurate with received Eb/N0. It is also now feasible to have embedded within the network of radios a networking system capable of allocating bandwidth in accordance with current needs and priorities. The subject of battlefield networking can now also be addressed. A system with the multiple degrees of freedom (e.g., ability to manually and automatically change communications parameters to improve communications performance, spectrum management and the ability to incorporate different mission processing support) will provide the warfighter, those who support the warfighter and the rapidly expanding mission of our armed forces (i.e., peacekeeping, anti-terrorism) to meet an ever-changing mission and operational environment. This paper will address how such a robust communications system will enhance the mission of the specialist and make the products of his efforts a real-time tool for the shooter who must operate within the digitized battlespace.

  8. The Telecommunications and Data Acquisition Report

    NASA Technical Reports Server (NTRS)

    Posner, E. C. (Editor)

    1983-01-01

    This publication reports on developments in programs managed by JPL's office of Telecommunications and Data Acquisition (TDA). In space communications, radio navigation, radio science, and ground based radio astronomy, it reports on activities of the Deep Space Network (DSN) and its associated Ground Communications Facility (GCF) in planning, in supporting research and technology, in implementation and in operations. In geodynamics, the publication reports on the application of radio interferometry at microwave frequencies for geodynamic measurements. This publication also reports on implementation and operations for searching the microwave spectrum.

  9. Mental health network governance: comparative analysis across Canadian regions.

    PubMed

    Wiktorowicz, Mary E; Fleury, Marie-Josée; Adair, Carol E; Lesage, Alain; Goldner, Elliot; Peters, Suzanne

    2010-10-26

    Modes of governance were compared in ten local mental health networks in diverse contexts (rural/urban and regionalized/non-regionalized) to clarify the governance processes that foster inter-organizational collaboration and the conditions that support them. Case studies of ten local mental health networks were developed using qualitative methods of document review, semi-structured interviews and focus groups that incorporated provincial policy, network and organizational levels of analysis. Mental health networks adopted either a corporate structure, mutual adjustment or an alliance governance model. A corporate structure supported by regionalization offered the most direct means for local governance to attain inter-organizational collaboration. The likelihood that networks with an alliance model developed coordination processes depended on the presence of the following conditions: a moderate number of organizations, goal consensus and trust among the organizations, and network-level competencies. In the small and mid-sized urban networks where these conditions were met their alliance realized the inter-organizational collaboration sought. In the large urban and rural networks where these conditions were not met, externally brokered forms of network governance were required to support alliance based models. In metropolitan and rural networks with such shared forms of network governance as an alliance or voluntary mutual adjustment, external mediation by a regional or provincial authority was an important lever to foster inter-organizational collaboration.

  10. Networks and Collaboration in Spanish Education Policy

    ERIC Educational Resources Information Center

    Azorín, Cecilia M.; Muijs, Daniel

    2017-01-01

    Background: Networks play an important role in today's societies. As a consequence, changes are apparent in the political, economic, cultural, educational and social agendas. Purpose: The main goal of this article is to map the situation of school networks in Spain. The research questions are focused on what forms collaboration and networking take…

  11. Landsat's international partners

    USGS Publications Warehouse

    Byrnes, Raymond A.

    2012-01-01

    Since the launch of the first Landsat satellite 40 years ago, International Cooperators (ICs) have formed a key strategic alliance with the U.S. Geological Survey (USGS) to not only engage in Landsat data downlink services but also to enable a foundation for scientific and technical collaboration. The map below shows the locations of all ground stations operated by the United States and IC ground station network for the direct downlink and distribution of Landsat 5 (L5) and Landsat 7 (L7) image data. The circles show the approximate area over which each station has the capability for direct reception of Landsat data. The red circles show the components of the L5 ground station network, the green circles show components of the L7 station network, and the dashed circles show stations with dual (L5 and L7) status. The yellow circles show L5 short-term ("campaign") stations that contribute to the USGS Landsat archive. Ground stations in South Dakota and Australia currently serve as the primary data capture facilities for the USGS Landsat Ground Network (LGN). The Landsat Ground Station (LGS) is located at the USGS Earth Resources Observation and Science (EROS) Center in Sioux Falls, South Dakota. The Alice Springs (ASN) ground station is located at the Geoscience Australia facility in Alice Springs, Australia. These sites receive the image data, via X-band Radio Frequency (RF) link, and the spacecraft housekeeping data, via S-band RF link. LGS also provides tracking services and a command link to the spacecrafts.

  12. A Volcano Monitoring Seismo-Acoustic Network in the CNMI

    NASA Astrophysics Data System (ADS)

    Howard, J. E.; Crippen, S. E.; Hayward, C.; Quick, J. E.

    2011-12-01

    In late spring and early summer of 2011, a seismo-acoustic network was installed in the Commonwealth of the Northern Mariana Islands (CNMI) for volcano monitoring. The network consists of a seismo-acoustic array on Saipan, an acoustic array on Sarigan with one seismometer, and a seismic network on Anatahan. On Saipan the array consists of a central site and 3 embedded triangular arrays with apertures of 100 m, 300 m and 1000 m. Four 50-foot porous hoses in a clover-leaf arrangement are used for spatial filtering at each acoustic site. Broadband seismometers were installed at the central site and the 1000 m sites. The Sarigan Array consists of a central acoustic site with 5 surrounding sites evenly spaced at 50 m radius, and one broadband seismic station. Two hoses were used for each site on Sarigan. Four broadband seismic stations were also installed on Anatahan which last erupted in 2005. Data from each array is sent by radio telemetry to the Emergency Management Office on Saipan, where it is routed to the USGS and SMU. Data will be used for volcano monitoring which will allow the CNMI to resume economic activity in the uninhabited northern islands. Initial data streams show high seismic noise levels as expected for an island installation. The Sarigan acoustic sites are also noisy as a result of being more exposed to wind than the Saipan sites. Many small events have already been observed in the infrasound data. This network was installed through the collaborative efforts of CNMI, USGS and SMU.

  13. Monitoring of manufacturing processes in the automotive industry using indoor location system

    NASA Astrophysics Data System (ADS)

    Ionescu, LM; Belu, N.; Rachieru, N.; Mazăre, AG; Anghel, D.-C.

    2016-08-01

    This paper presents a method for locating the operators, equipment and parts using radio communications systems. Specifically there will be radio transceiver arranged in a network of active and passive radio receivers placed on personnel, equipment or parts. Based on a radio triangulation method, it is determined the location of the all resources and parts involved in manufacturing process. The transceivers communicate with each other via “routers” - also components of the network. Such a structure may extend over large distances even in indoor spaces where there are obstacles (walls between rooms). The location is done by determining the power of transmission signal for at least three end points. The receiver position is then transmitted over the network through routers, to a central server where all positions of the resources are centralized. Our solution is a non-invasive and low cost method for determining resource position in the factory. The system can be used for both resource planning production for current process more efficient and for further analysis of the movement of resources during previous processes with possible adjustments to the workspace and re-planning of resources for future processes.

  14. A Spectrum Access Based on Quality of Service (QoS) in Cognitive Radio Networks.

    PubMed

    Zhai, Linbo; Wang, Hua; Gao, Chuangen

    2016-01-01

    The quality of service (QoS) is important issue for cognitive radio networks. In the cognitive radio system, the licensed users, also called primary users (PUs), are authorized to utilize the wireless spectrum, while unlicensed users, also called secondary users (SUs), are not authorized to use the wireless spectrum. SUs access the wireless spectrum opportunistically when the spectrum is idle. While SUs use an idle channel, the instance that PUs come back makes SUs terminate their communications and leave the current channel. Therefore, quality of service (QoS) is difficult to be ensured for SUs. In this paper, we first propose an analysis model to obtain QoS for cognitive radio networks such as blocking probability, completed traffic and termination probability of SUs. When the primary users use the channels frequently, QoS of SUs is difficult to be ensured, especially the termination probability. Then, we propose a channel reservation scheme to improve QoS of SUs. The scheme makes the terminated SUs move to the reserved channels and keep on communications. Simulation results show that our scheme can improve QoS of SUs especially the termination probability with a little cost of blocking probability in dynamic environment.

  15. Implications of Network Structure on Public Health Collaboratives

    ERIC Educational Resources Information Center

    Retrum, Jessica H.; Chapman, Carrie L.; Varda, Danielle M.

    2013-01-01

    Interorganizational collaboration is an essential function of public health agencies. These partnerships form social networks that involve diverse types of partners and varying levels of interaction. Such collaborations are widely accepted and encouraged, yet very little comparative research exists on how public health partnerships develop and…

  16. Improving Uptake of Key Perinatal Interventions Using Statewide Quality Collaboratives.

    PubMed

    Pai, Vidya V; Lee, Henry C; Profit, Jochen

    2018-06-01

    Regional and statewide quality improvement collaboratives have been instrumental in implementing evidence-based practices and facilitating quality improvement initiatives within neonatology. Statewide collaboratives emerged from larger collaborative organizations, like the Vermont Oxford Network, and play an increasing role in collecting and interpreting data, setting priorities for improvement, disseminating evidence-based clinical practice guidelines, and creating regional networks for synergistic learning. In this review, we highlight examples of successful statewide collaborative initiatives, as well as challenges that exist in initiating and sustaining collaborative efforts. Copyright © 2018 Elsevier Inc. All rights reserved.

  17. Hydrologic Observatory Data Telemetry Network in an Extreme Environment

    NASA Astrophysics Data System (ADS)

    Irving, K.; Kane, D.

    2007-12-01

    A network of hydrological research data stations on the North Slope of Alaska using radio telemetry to gather data in "near real time" will be described. The network consists of approximately 25 research stations, 10 repeater stations, and 3 Internet-connected base stations (though data is also collected at repeater stations and research stations may also function as repeaters). With this operational network, radio link redundancy is sufficient to reach any research station from any base station. The data network is driven in "pull" mode using software running on computers in Fairbanks, and emphasis is placed on reliably collecting and storing data as found on the remote data loggers. Work is underway to deploy dynamic routing software on the controlling computers, at which point the network will be capable of automatically working around problems which may include icing on antennas, satellite sun outages, animal damage, and many others.

  18. Hybrid Radio Frequency/Free-Space Optics (RF/FSO) Wireless Sensor Network: Security Concerns and Protective Measures

    NASA Astrophysics Data System (ADS)

    Banerjee, Koushik; Sharma, Hemant; Sengupta, Anasuya

    Wireless sensor networks (WSNs) are ad hoc wireless networks that are written off as spread out structure and ad hoc deployment. Sensor networks have all the rudimentary features of ad hoc networks but to altered points—for instance, considerably lesser movement and far more energy necessities. Commonly used technology for communication is radio frequency (RF) communications. Free-space optics (FSO) is relatively new technology which has the prospective to deliver remarkable increases in network lifetime of WSN. Hybrid RF/FSO communications has been suggested to decrease power consumption by a single sensor node. It is observed that security plays a very important role for either RF WSN or hybrid RF/FSO WSN as those are vulnerable to numerous threats. In this paper, various possible attacks in RF/FSO WSN are discussed and aimed to propose some way out from those attacks.

  19. Concepts for VLBI Station Control as Part of NEXPReS

    NASA Astrophysics Data System (ADS)

    Ettl, M.; Neidhardt, A.; Schönberger, M.; Alef, W.; Himwich, E.; Beaudoin, C.; Plötz, C.; Lovell, J.; Hase, H.

    2012-12-01

    In the Novel EXploration Pushing Robust e-VLBI Services-project (NEXPReS) the Technische Universität München (TUM) realizes concepts for continuous quality monitoring and station remote control in cooperation with the Max-Planck-Institute for Radio Astronomy, Bonn. NEXPReS is a three-year project, funded within the European Seventh Framework program. It is aimed to develop e-VLBI services for the European VLBI Network (EVN), which can also support the IVS observations (VLBI2010). Within this project, the TUM focuses on developments of an operational remote control system (e-RemoteCtrl) with authentication and authorization. It includes an appropriate role management with different remote access states for future observation strategies. To allow a flexible control of different systems in parallel, sophisticated graphical user interfaces are designed and realized. The software is currently under test in the new AuScope network, Australia/New Zealand. Additional system parameters and information are collected with a new system monitoring (SysMon) for a higher degree of automation, which is currently under preparation for standardization within the IVS Monitoring and Control Infrastructure (MCI) Collaboration Group. The whole system for monitoring and control is fully compatible with the NASA Field System and extends it.

  20. Plans for the New Korean VLBI Network (kvn)

    NASA Astrophysics Data System (ADS)

    Fletcher, Andre B.

    The new Korean VLBI Network construction project started in 2001. Currently funds have been allocated until 2007. Three new 20m diameter fast-slewing high-precision radio antennae will be built in South Korea at Seoul Tamna and Ulsan. These will be exclusively for VLBI astronomy astrometry and geodesy with a focus on developing millimeter-wave VLBI. First 2/8 22 43 and 86 GHz HEMT receivers will be used; 100/150 GHz SIS receivers will be installed later. The KVN Data Acquisition System (DAS) is being designed to realize a multi-band dual-circular polarization wide-bandwidth system. Very-high-speed digital samplers will generate data streams at rates of at least 1 Gigabit/s and a digital filter system will select the recorded frequency channels according to several observation modes one or more of which would be compatible with the VLBA and VERA DASs. The data will be transmitted by optical fibers to the new MIT Mark 5B hard-disk recorders. The KVN correlator will be designed with new technological concepts in mind. The observational capabilities and science goals of KVN are outlined. International scientific and technical collaborations with VLBI institutes will be essential for the ultimate success of the KVN project

  1. Radio-Frequency and Wideband Modulation Arraying

    NASA Technical Reports Server (NTRS)

    Brockman, M. H.

    1984-01-01

    Summing network receives coherent signals from all receivers in array. Method sums narrow-band radio-frequency (RF) carrier powers and wide-band spectrum powers of array of separate antenna/receiver systems designed for phase-locked-loop or suppressed-carrier operation.

  2. The development of a network for community-based obesity prevention: the CO-OPS Collaboration

    PubMed Central

    2011-01-01

    Background Community-based interventions are a promising approach and an important component of a comprehensive response to obesity. In this paper we describe the Collaboration of COmmunity-based Obesity Prevention Sites (CO-OPS Collaboration) in Australia as an example of a collaborative network to enhance the quality and quantity of obesity prevention action at the community level. The core aims of the CO-OPS Collaboration are to: identify and analyse the lessons learned from a range of community-based initiatives aimed at tackling obesity, and; to identify the elements that make community-based obesity prevention initiatives successful and share the knowledge gained with other communities. Methods Key activities of the collaboration to date have included the development of a set of Best Practice Principles and knowledge translation and exchange activities to promote the application (or use) of evidence, evaluation and analysis in practice. Results The establishment of the CO-OPS Collaboration is a significant step toward strengthening action in this area, by bringing together research, practice and policy expertise to promote best practice, high quality evaluation and knowledge translation and exchange. Future development of the network should include facilitation of further evidence generation and translation drawing from process, impact and outcome evaluation of existing community-based interventions. Conclusions The lessons presented in this paper may help other networks like CO-OPS as they emerge around the globe. It is important that networks integrate with each other and share the experience of creating these networks. PMID:21349185

  3. A Community-Building Framework for Collaborative Research Coordination across the Education and Biology Research Disciplines.

    PubMed

    Pelaez, Nancy; Anderson, Trevor R; Gardner, Stephanie M; Yin, Yue; Abraham, Joel K; Bartlett, Edward L; Gormally, Cara; Hurney, Carol A; Long, Tammy M; Newman, Dina L; Sirum, Karen; Stevens, Michael T

    2018-06-01

    Since 2009, the U.S. National Science Foundation Directorate for Biological Sciences has funded Research Coordination Networks (RCN) aimed at collaborative efforts to improve participation, learning, and assessment in undergraduate biology education (UBE). RCN-UBE projects focus on coordination and communication among scientists and educators who are fostering improved and innovative approaches to biology education. When faculty members collaborate with the overarching goal of advancing undergraduate biology education, there is a need to optimize collaboration between participants in order to deeply integrate the knowledge across disciplinary boundaries. In this essay we propose a novel guiding framework for bringing colleagues together to advance knowledge and its integration across disciplines, the "Five 'C's' of Collaboration: Commitment, Collegiality, Communication, Consensus, and Continuity." This guiding framework for professional network practice is informed by both relevant literature and empirical evidence from community-building experience within the RCN-UBE Advancing Competencies in Experimentation-Biology (ACE-Bio) Network. The framework is presented with practical examples to illustrate how it might be used to enhance collaboration between new and existing participants in the ACE-Bio Network as well as within other interdisciplinary networks.

  4. Spread Spectrum Based Energy Efficient Collaborative Communication in Wireless Sensor Networks.

    PubMed

    Ghani, Anwar; Naqvi, Husnain; Sher, Muhammad; Khan, Muazzam Ali; Khan, Imran; Irshad, Azeem

    2016-01-01

    Wireless sensor networks consist of resource limited devices. Most crucial of these resources is battery life, as in most applications like battle field or volcanic area monitoring, it is often impossible to replace or recharge the power source. This article presents an energy efficient collaborative communication system based on spread spectrum to achieve energy efficiency as well as immunity against jamming, natural interference, noise suppression and universal frequency reuse. Performance of the proposed system is evaluated using the received signal power, bit error rate (BER) and energy consumption. The results show a direct proportionality between the power gain and the number of collaborative nodes as well as BER and signal-to-noise ratio (Eb/N0). The analytical and simulation results of the proposed system are compared with SISO system. The comparison reveals that SISO perform better than collaborative communication in case of small distances whereas collaborative communication performs better than SISO in case of long distances. On the basis of these results it is safe to conclude that collaborative communication in wireless sensor networks using wideband systems improves the life time of nodes in the networks thereby prolonging the network's life time.

  5. Architecture and System Engineering Development Study of Space-Based Satellite Networks for NASA Missions

    NASA Technical Reports Server (NTRS)

    Ivancic, William D.

    2003-01-01

    Traditional NASA missions, both near Earth and deep space, have been stovepipe in nature and point-to-point in architecture. Recently, NASA and others have conceptualized missions that required space-based networking. The notion of networks in space is a drastic shift in thinking and requires entirely new architectures, radio systems (antennas, modems, and media access), and possibly even new protocols. A full system engineering approach for some key mission architectures will occur that considers issues such as the science being performed, stationkeeping, antenna size, contact time, data rates, radio-link power requirements, media access techniques, and appropriate networking and transport protocols. This report highlights preliminary architecture concepts and key technologies that will be investigated.

  6. The Radio Jove Project

    NASA Technical Reports Server (NTRS)

    Thieman, J. R.

    2010-01-01

    The Radio love Project is a hands-on education and outreach project in which students, or any other interested individuals or groups build a radio telescope from a kit, operate the radio telescope, transmit the resulting signals through the internet if desired, analyze the results, and share the results with others through archives or general discussions among the observers. Radio love is intended to provide an introduction to radio astronomy for the observer. The equipment allows the user to observe radio signals from Jupiter, the Sun, the galaxy, and Earth-based radiation both natural and man-made. The project was started through a NASA Director's Discretionary Fund grant more than ten years ago. it has continued to be carried out through the dedicated efforts of a group of mainly volunteers. Dearly 1500 kits have been distributed throughout the world. Participation can also be done without building a kit. Pre-built kits are available. Users can also monitor remote radio telescopes through the internet using free downloadable software available through the radiosky.com website. There have been many stories of prize-winning projects, inspirational results, collaborative efforts, etc. We continue to build the community of observers and are always open to new thoughts about how to inspire the observers to still greater involvement in the science and technology associated with Radio Jove.

  7. The National Public Health Leadership Institute: evaluation of a team-based approach to developing collaborative public health leaders.

    PubMed

    Umble, Karl; Steffen, David; Porter, Janet; Miller, Delesha; Hummer-McLaughlin, Kelley; Lowman, Amy; Zelt, Susan

    2005-04-01

    Recent public health literature contains calls for collaborative public health interventions and for leaders capable of guiding them. The National Public Health Leadership Institute aims to develop collaborative leaders and to strengthen networks of leaders who share knowledge and jointly address public health problems. Evaluation results show that completing the institute training increases collaborative leadership and builds knowledge-sharing and problem-solving networks. These practices and networks strengthen interorganizational relationships, coalitions, services, programs, and policies. Intensive team-and project-based learning are key to the program's impact.

  8. The National Public Health Leadership Institute: Evaluation of a Team-Based Approach to Developing Collaborative Public Health Leaders

    PubMed Central

    Umble, Karl; Steffen, David; Porter, Janet; Miller, Delesha; Hummer-McLaughlin, Kelley; Lowman, Amy; Zelt, Susan

    2005-01-01

    Recent public health literature contains calls for collaborative public health interventions and for leaders capable of guiding them. The National Public Health Leadership Institute aims to develop collaborative leaders and to strengthen networks of leaders who share knowledge and jointly address public health problems. Evaluation results show that completing the institute training increases collaborative leadership and builds knowledge-sharing and problem-solving networks. These practices and networks strengthen interorganizational relationships, coalitions, services, programs, and policies. Intensive team-and project-based learning are key to the program’s impact. PMID:15798124

  9. Public Safety Networks--Examining Mimetic, Complexity, and Legacy Effects on Interorganizational Collaborations

    ERIC Educational Resources Information Center

    Dias, Martin A.

    2012-01-01

    The purpose of this dissertation is to examine information systems-enabled interorganizational collaborations called public safety networks--their proliferation, information systems architecture, and technology evolution. These networks face immense pressures from member organizations, external stakeholders, and environmental contingencies. This…

  10. Surface Accuracy and Pointing Error Prediction of a 32 m Diameter Class Radio Astronomy Telescope

    NASA Astrophysics Data System (ADS)

    Azankpo, Severin

    2017-03-01

    The African Very-long-baseline interferometry Network (AVN) is a joint project between South Africa and eight partner African countries aimed at establishing a VLBI (Very-Long-Baseline Interferometry) capable network of radio telescopes across the African continent. An existing structure that is earmarked for this project, is a 32 m diameter antenna located in Ghana that has become obsolete due to advances in telecommunication. The first phase of the conversion of this Ghana antenna into a radio astronomy telescope is to upgrade the antenna to observe at 5 GHz to 6.7 GHz frequency and then later to 18 GHz within a required performing tolerance. The surface and pointing accuracies for a radio telescope are much more stringent than that of a telecommunication antenna. The mechanical pointing accuracy of such telescopes is influenced by factors such as mechanical alignment, structural deformation, and servo drive train errors. The current research investigates the numerical simulation of the surface and pointing accuracies of the Ghana 32 m diameter radio astronomy telescope due to its structural deformation mainly influenced by gravity, wind and thermal loads.

  11. Geotechnical sensing using electromagnetic attenuation between radio transceivers

    NASA Astrophysics Data System (ADS)

    Ghazanfari, Ehsan; Pamukcu, Sibel; Yoon, Suk-Un; Suleiman, Muhannad T.; Cheng, Liang

    2012-12-01

    Monitoring the onset of a geo-event such as the intrusion of a chemical plume or a slow progressive mass slide that results in marked changes in the physical properties of the host soil could be potentially accomplished using a distributed network of embedded radio transceivers. This paper introduces a new concept of subsurface geo-event monitoring, which takes advantage of the spatial and temporal variations in signal strength of electromagnetic (EM) waves transmitted within the net of distributed radios within a sensing area. Results of experiments in the laboratory and the field demonstrated that variations in EM signal strength could be used to detect physical changes in the subsurface. Changes in selected physical properties of host soil including water content, density, and formation of discontinuities could be discerned from the changes in the signal strength of the transmitted wave between embedded radio transceivers. Good agreement was observed between a theoretical model and the experimental results for inter-transceiver distances less than 55 cm. These results demonstrated a viable new approach for distributed sensing and monitoring of subsurface hazards for civil infrastructure within a networked domain of radio transceivers.

  12. Radio Galaxy Zoo: compact and extended radio source classification with deep learning

    NASA Astrophysics Data System (ADS)

    Lukic, V.; Brüggen, M.; Banfield, J. K.; Wong, O. I.; Rudnick, L.; Norris, R. P.; Simmons, B.

    2018-05-01

    Machine learning techniques have been increasingly useful in astronomical applications over the last few years, for example in the morphological classification of galaxies. Convolutional neural networks have proven to be highly effective in classifying objects in image data. In the context of radio-interferometric imaging in astronomy, we looked for ways to identify multiple components of individual sources. To this effect, we design a convolutional neural network to differentiate between different morphology classes using sources from the Radio Galaxy Zoo (RGZ) citizen science project. In this first step, we focus on exploring the factors that affect the performance of such neural networks, such as the amount of training data, number and nature of layers, and the hyperparameters. We begin with a simple experiment in which we only differentiate between two extreme morphologies, using compact and multiple-component extended sources. We found that a three-convolutional layer architecture yielded very good results, achieving a classification accuracy of 97.4 per cent on a test data set. The same architecture was then tested on a four-class problem where we let the network classify sources into compact and three classes of extended sources, achieving a test accuracy of 93.5 per cent. The best-performing convolutional neural network set-up has been verified against RGZ Data Release 1 where a final test accuracy of 94.8 per cent was obtained, using both original and augmented images. The use of sigma clipping does not offer a significant benefit overall, except in cases with a small number of training images.

  13. Communication Resource Use in a Networked Collaborative Design Environment.

    ERIC Educational Resources Information Center

    Gay, Geri; Lentini, Marc

    The purpose of this exploratory study was to examine student use of a prototype networked collaborative design environment to support or augment learning about engineering design. The theoretical framework is based primarily on Vygotsky's social construction of knowledge and the belief that collaboration and communication are critical components…

  14. Building a Model for Distance Collaboration in the Computer-Assisted Business Communication Classroom.

    ERIC Educational Resources Information Center

    Lopez, Elizabeth Sanders; Nagelhout, Edwin

    1995-01-01

    Outlines a model for distance collaboration between business writing classrooms using network technology. Discusses ways to teach national and international audience awareness, problem solving, and the contextual nature of cases. Discusses goals for distance collaboration, sample assignments, and the pros and cons of network technologies. (SR)

  15. Downlink power distributions for 2G and 3G mobile communication networks.

    PubMed

    Colombi, Davide; Thors, Björn; Persson, Tomas; Wirén, Niklas; Larsson, Lars-Eric; Jonsson, Mikael; Törnevik, Christer

    2013-12-01

    Knowledge of realistic power levels is key when conducting accurate EMF exposure assessments. In this study, downlink output power distributions for radio base stations in 2G and 3G mobile communication networks have been assessed. The distributions were obtained from network measurement data collected from the Operations Support System, which normally is used for network monitoring and management. Significant amounts of data were gathered simultaneously for large sets of radio base stations covering wide geographical areas and different environments. The method was validated with in situ measurements. For the 3G network, the 90th percentile of the averaged output power during high traffic hours was found to be 43 % of the maximum available power. The corresponding number for 2G, with two or more transceivers installed, was 65 % or below.

  16. 47 CFR 76.93 - Parties entitled to network non-duplication protection.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 47 Telecommunication 4 2010-10-01 2010-10-01 false Parties entitled to network non-duplication... RADIO SERVICES MULTICHANNEL VIDEO AND CABLE TELEVISION SERVICE Network Non-duplication Protection, Syndicated Exclusivity and Sports Blackout § 76.93 Parties entitled to network non-duplication protection...

  17. 47 CFR 76.92 - Cable network non-duplication; extent of protection.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 47 Telecommunication 4 2011-10-01 2011-10-01 false Cable network non-duplication; extent of... RADIO SERVICES MULTICHANNEL VIDEO AND CABLE TELEVISION SERVICE Network Non-duplication Protection, Syndicated Exclusivity and Sports Blackout § 76.92 Cable network non-duplication; extent of protection. (a...

  18. 47 CFR 76.93 - Parties entitled to network non-duplication protection.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 47 Telecommunication 4 2011-10-01 2011-10-01 false Parties entitled to network non-duplication... RADIO SERVICES MULTICHANNEL VIDEO AND CABLE TELEVISION SERVICE Network Non-duplication Protection, Syndicated Exclusivity and Sports Blackout § 76.93 Parties entitled to network non-duplication protection...

  19. 47 CFR 76.92 - Cable network non-duplication; extent of protection.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 47 Telecommunication 4 2010-10-01 2010-10-01 false Cable network non-duplication; extent of... RADIO SERVICES MULTICHANNEL VIDEO AND CABLE TELEVISION SERVICE Network Non-duplication Protection, Syndicated Exclusivity and Sports Blackout § 76.92 Cable network non-duplication; extent of protection. (a...

  20. Pacific Educational Computer Network Study. Final Report.

    ERIC Educational Resources Information Center

    Hawaii Univ., Honolulu. ALOHA System.

    The Pacific Educational Computer Network Feasibility Study examined technical and non-technical aspects of the formation of an international Pacific Area computer network for higher education. The technical study covered the assessment of the feasibility of a packet-switched satellite and radio ground distribution network for data transmission…

  1. An Examination of Research Collaboration in Psychometrics Utilizing Social Network Analysis Methods

    ERIC Educational Resources Information Center

    DiCrecchio, Nicole C.

    2016-01-01

    Co-authorship networks have been studied in many fields as a way to understand collaboration patterns. However, a comprehensive exploration of the psychometrics field has not been conducted. Also, few studies on co-author networks have included longitudinal analyses as well as data on the characteristics of authors in the network. Including both…

  2. Engendering Climate Information Networks in Africa: Case Studies of Digital and FM Radio for Disseminating Disaster Early Warnings to Women and Youth

    NASA Astrophysics Data System (ADS)

    Stewart, M. M.; Pratt, M.

    2002-05-01

    This paper examines the effectiveness of FM and digital radio in disseminating weather and climate information to remote rural populations in Niger and Uganda. In Niger, poor communications infrastructure necessitated the establishment of a basic radio system as a first step towards disseminating climate information. Dissemination via digital radio is limited, in this context, by lack of technical support and the difficulty of maintaining computer equipment in the hot and dusty climate. Community FM stations have supported a range of mitigation activities that reduced vulnerability in all sites studied. Digital radio proved a more effective tool for disseminating climate information in Uganda, where technical knowledge is more prevalent and infrastructure networks are stronger. The primary challenge in Uganda lies in maintaining equipment in remote locations and disseminating information to a wider audience by linking with FM radio. Climate and weather information is already demonstrating positive impacts on agricultural production in Uganda, health and civil society in Niger, and on vulnerability reduction in both countries. Radio,particularly FM, was an excellent medium for disseminating information to women, youth, and other hard to reach populations. Discussion will focus on recommendations for improving the effectiveness of both systems and for practically linking FM and digital dissemination systems for better communication of climate information. Implications of the case studies will also be discussed in the context of digital and FM radio as media for disseminating other types of scientific information.

  3. 47 CFR 74.632 - Licensing requirements.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 47 Telecommunication 4 2013-10-01 2013-10-01 false Licensing requirements. 74.632 Section 74.632 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) BROADCAST RADIO SERVICES EXPERIMENTAL RADIO... stations, and broadcast network-entities and, further, on a secondary basis, to licensees of low power...

  4. 47 CFR 74.632 - Licensing requirements.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 47 Telecommunication 4 2012-10-01 2012-10-01 false Licensing requirements. 74.632 Section 74.632 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) BROADCAST RADIO SERVICES EXPERIMENTAL RADIO... stations, and broadcast network-entities and, further, on a secondary basis, to licensees of low power...

  5. 47 CFR 74.632 - Licensing requirements.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 47 Telecommunication 4 2014-10-01 2014-10-01 false Licensing requirements. 74.632 Section 74.632 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) BROADCAST RADIO SERVICES EXPERIMENTAL RADIO... stations, and broadcast network-entities and, further, on a secondary basis, to licensees of low power...

  6. 47 CFR 74.632 - Licensing requirements.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 47 Telecommunication 4 2011-10-01 2011-10-01 false Licensing requirements. 74.632 Section 74.632 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) BROADCAST RADIO SERVICES EXPERIMENTAL RADIO... stations, and broadcast network-entities and, further, on a secondary basis, to licensees of low power...

  7. High-Throughput, Survivable Protocols for CDMA Packet-Radio Networks (SRNTN-74)

    DTIC Science & Technology

    1990-03-01

    published in a paper by Jubin and Tornow [2], however the reader must be aware that the current SURAP algorithms deviate slightly from this reference...threading policy outlined by Jubin and Tornow is equivalent to a link- level window size of one, meaning a policy of not transmitting a new packet to a... Tornow . The DARPA packet-radio network protocols. Proceedings of the IEEE, 75(1):21-32, January 1987. [31 N. Gower and J. Jubin. Congestion control using

  8. On Alarm Protocol in Wireless Sensor Networks

    NASA Astrophysics Data System (ADS)

    Cichoń, Jacek; Kapelko, Rafał; Lemiesz, Jakub; Zawada, Marcin

    We consider the problem of efficient alarm protocol for ad-hoc radio networks consisting of devices that try to gain access for transmission through a shared radio communication channel. The problem arise in tasks that sensors have to quickly inform the target user about an alert situation such as presence of fire, dangerous radiation, seismic vibrations, and more. In this paper, we present a protocol which uses O(logn) time slots and show that Ω(logn/loglogn) is a lower bound for used time slots.

  9. Source Localization in a Cognitive Radio Environment Consisting of Frequency and Spatial Mobility

    DTIC Science & Technology

    2011-12-01

    are designed to track position over time using a wireless RF sensor network, such as Kalman filtering [13]. 74 THIS PAGE INTENTIONALLY LEFT BLANK...Radio,” Proceedings of the IEEE, vol. 97, no. 4, pp. 612–625, Apr. 2009. 80 [12] J. B. Bernthal, T. X. Brown , D. N. Hatfield, D. C. Sicker, P. A... Kalman Filtering in Wireless Sensor Networks,” IEEE Control Systems, vol. 30, no. 2, pp. 66–86, April 2010. [14] J. Nemeroff, L. Garcia, D

  10. Report of the Defense Science Board Task Force on Wideband Radio Frequency Modulation: Dynamic Access to Mobile Information Networks

    DTIC Science & Technology

    2003-07-01

    Centric Architecture Office ( NCAO ) should develop an RF communications/network management technology roadmap. The roadmap should serve two purposes: a...Centric Architecture Office ( NCAO ) chartered with integrating diverse DoD efforts to provide technical alternatives to the current form of radio...American people as a cornerstone of DoD’s leadership of the public trust in this area. The NCAO should be consolidated from ongoing NII, JTRS JPO and DDR

  11. Spectrum sensing algorithm based on autocorrelation energy in cognitive radio networks

    NASA Astrophysics Data System (ADS)

    Ren, Shengwei; Zhang, Li; Zhang, Shibing

    2016-10-01

    Cognitive radio networks have wide applications in the smart home, personal communications and other wireless communication. Spectrum sensing is the main challenge in cognitive radios. This paper proposes a new spectrum sensing algorithm which is based on the autocorrelation energy of signal received. By taking the autocorrelation energy of the received signal as the statistics of spectrum sensing, the effect of the channel noise on the detection performance is reduced. Simulation results show that the algorithm is effective and performs well in low signal-to-noise ratio. Compared with the maximum generalized eigenvalue detection (MGED) algorithm, function of covariance matrix based detection (FMD) algorithm and autocorrelation-based detection (AD) algorithm, the proposed algorithm has 2 11 dB advantage.

  12. Wireless sensor for temperature and humidity measurement

    NASA Astrophysics Data System (ADS)

    Drumea, Andrei; Svasta, Paul

    2010-11-01

    Temperature and humidity sensors have a broad range of applications, from heating and ventilation of houses to controlled drying of fruits, vegetables or meat in food industry. Modern sensors are integrated devices, usually MEMS, factory-calibrated and with digital output of measured parameters. They can have power down modes for reduced energy consumption. Such an integrated device allows the implementation of a battery powered wireless sensor when coupled with a low power microcontroller and a radio subsystem. A radio sensor can work independently or together with others in a radio network. Presented paper focuses mainly on measurement and construction aspects of sensors for temperature and humidity designed and implemented by authors; network aspects (communication between two or more sensors) are not analyzed.

  13. Building a Community of Practice for Researchers: The International Network for Simulation-Based Pediatric Innovation, Research and Education.

    PubMed

    Cheng, Adam; Auerbach, Marc; Calhoun, Aaron; Mackinnon, Ralph; Chang, Todd P; Nadkarni, Vinay; Hunt, Elizabeth A; Duval-Arnould, Jordan; Peiris, Nicola; Kessler, David

    2018-06-01

    The scope and breadth of simulation-based research is growing rapidly; however, few mechanisms exist for conducting multicenter, collaborative research. Failure to foster collaborative research efforts is a critical gap that lies in the path of advancing healthcare simulation. The 2017 Research Summit hosted by the Society for Simulation in Healthcare highlighted how simulation-based research networks can produce studies that positively impact the delivery of healthcare. In 2011, the International Network for Simulation-based Pediatric Innovation, Research and Education (INSPIRE) was formed to facilitate multicenter, collaborative simulation-based research with the aim of developing a community of practice for simulation researchers. Since its formation, the network has successfully completed and published numerous collaborative research projects. In this article, we describe INSPIRE's history, structure, and internal processes with the goal of highlighting the community of practice model for other groups seeking to form a simulation-based research network.

  14. Assembling the puzzle for promoting physical activity in Brazil: a social network analysis.

    PubMed

    Brownson, Ross C; Parra, Diana C; Dauti, Marsela; Harris, Jenine K; Hallal, Pedro C; Hoehner, Christine; Malta, Deborah Carvalho; Reis, Rodrigo S; Ramos, Luiz Roberto; Ribeiro, Isabela C; Soares, Jesus; Pratt, Michael

    2010-07-01

    Physical inactivity is a significant public health problem in Brazil that may be addressed by partnerships and networks. In conjunction with Project GUIA (Guide for Useful Interventions for Physical Activity in Brazil and Latin America), the aim of this study was to conduct a social network analysis of physical activity in Brazil. An online survey was completed by 28 of 35 organizations contacted from December 2008 through March 2009. Network analytic methods examined measures of collaboration, importance, leadership, and attributes of the respondent and organization. Leadership nominations for organizations studied ranged from 0 to 23. Positive predictors of collaboration included: south region, GUIA membership, years working in physical activity, and research, education, and promotion/practice areas of physical activity. The most frequently reported barrier to collaboration was bureaucracy. Social network analysis identified factors that are likely to improve collaboration among organizations in Brazil.

  15. Disaster preparedness networks in rural Midwest communities: Organizational roles, collaborations, and support for older residents.

    PubMed

    Ashida, Sato; Zhu, Xi; Robinson, Erin L; Schroer, Audrey

    2018-05-17

    This study investigated the roles and interconnections among community organizations belonging to local disaster coalitions in Midwest in supporting older residents. Representatives from 44 organizations participated in one-time survey. Most were non-profit (68%) or federal/state/local government agencies (23%). The analyses of 761 relationships showed stronger collaborations in assessment (average strength=2.88 on a 5-point scale), emergency response (2.72), and planning (2.61); and weaker collaborations in co-sponsoring programs (1.71) and supporting older residents (2.03). The extent of collaboration (network density) to support older adults was also low. Coalitions may enhance network density and centralization by developing sub-committee structure and strengthening existing collaborations.

  16. Exploring Systems Engineering (and the Universe) Through the RadioJOVE telescope

    NASA Astrophysics Data System (ADS)

    Aditi Raj, Anya

    2017-01-01

    Amateur projects in radio astronomy are popular methods to engage in what often seems to be an inaccessible field, and pre-made kits are becoming increasingly available to hobbyists and educators. One such kit is the RadioJOVE, which is attractive due to its simplicity, accessibility and its extensive support network and community of users. When coupled with an education in project management, building the RadioJOVE provides a perfect framework to learn about best practices in completing a project. We will primarily discuss the use of the RadioJOVE project to enhance study in project management and systems engineering. We also intend to discuss the importance of amateur projects such as the RadioJOVE in gaining a holistic understanding of radio astronomy and the project’s potential to spark interest in radio astronomy in students of various disciplines.

  17. Juno Radio Science Observations and Gravity Science Calibrations of Plasma Electron Content in Io Plasma Torus

    NASA Astrophysics Data System (ADS)

    Yang, Y. M.; Buccino, D.; Folkner, W. M.; Oudrhiri, K.; Phipps, P. H.; Parisi, M.; Kahan, D. S.

    2017-12-01

    Interplanetary and Earth ionosphere plasma electrons can have significant impacts on radio frequency signal propagation such as telecommunication between spacecraft and the Deep Space Network (DSN). On 27 August 2016, the first closest approach of The Juno spacecraft (Perijove 1) provided an opportunity to observe plasma electrons inside of the Io plasma torus using radio science measurements from Juno. Here, we report on the derivations of plasma electron content in the Io plasma torus by using two-way coherent radio science measurements made from Juno's Gravity Science Instrument and the Deep Space Network. During Perijove 1, Juno spacecraft passed through the inner region (perijove altitude of 1.06 Jovian Radii) between Jupiter and the Io plasma torus. Significant plasma electron variations of up to 30 TEC units were observed while the radio link between Juno and the DSN traveled through the Io plasma torus. In this research, we compare observations made by open-loop and closed-loop processes using different frequency radio signals, corresponding Io plasma torus model simulations, and other Earth ionosphere observations. The results of three-dimensional Io plasma model simulations are consistent with observations with some discrepancies. Results are shown to improve our understanding of the Io plasma torus effect on Juno gravity science measurements and its calibrations to reduce the corresponding (non-gravity field induced) radio frequency shift.

  18. A framework using cluster-based hybrid network architecture for collaborative virtual surgery.

    PubMed

    Qin, Jing; Choi, Kup-Sze; Poon, Wai-Sang; Heng, Pheng-Ann

    2009-12-01

    Research on collaborative virtual environments (CVEs) opens the opportunity for simulating the cooperative work in surgical operations. It is however a challenging task to implement a high performance collaborative surgical simulation system because of the difficulty in maintaining state consistency with minimum network latencies, especially when sophisticated deformable models and haptics are involved. In this paper, an integrated framework using cluster-based hybrid network architecture is proposed to support collaborative virtual surgery. Multicast transmission is employed to transmit updated information among participants in order to reduce network latencies, while system consistency is maintained by an administrative server. Reliable multicast is implemented using distributed message acknowledgment based on cluster cooperation and sliding window technique. The robustness of the framework is guaranteed by the failure detection chain which enables smooth transition when participants join and leave the collaboration, including normal and involuntary leaving. Communication overhead is further reduced by implementing a number of management approaches such as computational policies and collaborative mechanisms. The feasibility of the proposed framework is demonstrated by successfully extending an existing standalone orthopedic surgery trainer into a collaborative simulation system. A series of experiments have been conducted to evaluate the system performance. The results demonstrate that the proposed framework is capable of supporting collaborative surgical simulation.

  19. VLA radio upper limit on a Type IIn SN 2008B

    NASA Astrophysics Data System (ADS)

    Chandra, Poonam; Soderberg, Alicia

    2008-01-01

    Poonam Chandra and Alicia Soderberg report on behalf of a larger collaboration: We observed a Type IIn supernova SN 2008B (CBET 1194) with the Very Large Array (VLA) in the 8.46 GHz band on 2008, January 23.5 UT. The observations were taken for total duration of one hour in the VLA B-configuration. We do not detect any radio emission at the supernova position (CBET 1194). The flux density at the supernova position is 60 ± 28 uJy.

  20. VLA radio upper limit on Type IIn Supernova 2007rt

    NASA Astrophysics Data System (ADS)

    Chandra, Poonam; Soderberg, Alicia

    2008-01-01

    Poonam Chandra and Alicia Soderberg report on behalf of a larger collaboration: We observed a Type IIn supernova SN 2007rt (CBET 1148) with the Very Large Array (VLA) in the 8.46 GHz band on 2008, January 12.55 UT. The observations were taken for total duration of one hour in the VLA B-configuration. We do not detect any radio emission at the supernova position (CBET 1148). The flux density at the supernova position is 9 ± 27 uJy.

  1. Responses to a questionnaire on networking between OIE Reference Laboratories and OIE Collaborating Centres.

    PubMed

    Brückner, G K; Linnane, S; Diaz, F; Vallat, B

    2007-01-01

    Two separate questionnaires were distributed to 20 OIE Collaborating Centres and 160 OIE Reference Laboratories to assess the current status of networking and collaboration among OIE Reference Laboratories and between OIE Reference Laboratories and OIE Collaborating Centres. The questionnaire for the OIE Reference Laboratories contained 7 sections with questions on networking between laboratories, reporting of information, biosecurity quality control, and financing. Emphasis was placed in obtaining information on inter-laboratory relationships and exchange of expertise, training needs and sharing of data and information. The questionnaire for the OIE Collaborating Centres contained six sections with the emphasis on aspects related to awareness of services that can be provided, expertise that could be made available, sharing of information and the relationship with the national veterinary services of the countries concerned. The responses to the questionnaires were collated, categorised and statistically evaluated to allow for tentative inferences on the data provided. Valuable information emanated from the data identifying the current status of networking and indicating possible shortcomings that could be addressed to improve networking.

  2. Emergence of Multiplex Communities in Collaboration Networks.

    PubMed

    Battiston, Federico; Iacovacci, Jacopo; Nicosia, Vincenzo; Bianconi, Ginestra; Latora, Vito

    2016-01-01

    Community structures in collaboration networks reflect the natural tendency of individuals to organize their work in groups in order to better achieve common goals. In most of the cases, individuals exploit their connections to introduce themselves to new areas of interests, giving rise to multifaceted collaborations which span different fields. In this paper, we analyse collaborations in science and among movie actors as multiplex networks, where the layers represent respectively research topics and movie genres, and we show that communities indeed coexist and overlap at the different layers of such systems. We then propose a model to grow multiplex networks based on two mechanisms of intra and inter-layer triadic closure which mimic the real processes by which collaborations evolve. We show that our model is able to explain the multiplex community structure observed empirically, and we infer the strength of the two underlying social mechanisms from real-world systems. Being also able to correctly reproduce the values of intra-layer and inter-layer assortativity correlations, the model contributes to a better understanding of the principles driving the evolution of social networks.

  3. Adaptive threshold determination for efficient channel sensing in cognitive radio network using mobile sensors

    NASA Astrophysics Data System (ADS)

    Morshed, M. N.; Khatun, S.; Kamarudin, L. M.; Aljunid, S. A.; Ahmad, R. B.; Zakaria, A.; Fakir, M. M.

    2017-03-01

    Spectrum saturation problem is a major issue in wireless communication systems all over the world. Huge number of users is joining each day to the existing fixed band frequency but the bandwidth is not increasing. These requirements demand for efficient and intelligent use of spectrum. To solve this issue, the Cognitive Radio (CR) is the best choice. Spectrum sensing of a wireless heterogeneous network is a fundamental issue to detect the presence of primary users' signals in CR networks. In order to protect primary users (PUs) from harmful interference, the spectrum sensing scheme is required to perform well even in low signal-to-noise ratio (SNR) environments. Meanwhile, the sensing period is usually required to be short enough so that secondary (unlicensed) users (SUs) can fully utilize the available spectrum. CR networks can be designed to manage the radio spectrum more efficiently by utilizing the spectrum holes in primary user's licensed frequency bands. In this paper, we have proposed an adaptive threshold detection method to detect presence of PU signal using free space path loss (FSPL) model in 2.4 GHz WLAN network. The model is designed for mobile sensors embedded in smartphones. The mobile sensors acts as SU while the existing WLAN network (channels) works as PU. The theoretical results show that the desired threshold range detection of mobile sensors mainly depends on the noise floor level of the location in consideration.

  4. Analysis of power management and system latency in wireless sensor networks

    NASA Astrophysics Data System (ADS)

    Oswald, Matthew T.; Rohwer, Judd A.; Forman, Michael A.

    2004-08-01

    Successful power management in a wireless sensor network requires optimization of the protocols which affect energy-consumption on each node and the aggregate effects across the larger network. System optimization for a given deployment scenario requires an analysis and trade off of desired node and network features with their associated costs. The sleep protocol for an energy-efficient wireless sensor network for event detection, target classification, and target tracking developed at Sandia National Laboratories is presented. The dynamic source routing (DSR) algorithm is chosen to reduce network maintenance overhead, while providing a self-configuring and self-healing network architecture. A method for determining the optimal sleep time is developed and presented, providing reference data which spans several orders of magnitude. Message timing diagrams show, that a node in a five-node cluster, employing an optimal cyclic single-radio sleep protocol, consumes 3% more energy and incurs a 16-s increase latency than nodes employing the more complex dual-radio STEM protocol.

  5. 47 CFR 90.1410 - Network sharing agreement.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 47 Telecommunication 5 2010-10-01 2010-10-01 false Network sharing agreement. 90.1410 Section 90... PRIVATE LAND MOBILE RADIO SERVICES 700 MHz Public/Private Partnership § 90.1410 Network sharing agreement... related entities as the Commission may require or allow will be governed by the Network Sharing Agreement...

  6. 47 CFR 90.1410 - Network sharing agreement.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 47 Telecommunication 5 2011-10-01 2011-10-01 false Network sharing agreement. 90.1410 Section 90... PRIVATE LAND MOBILE RADIO SERVICES 700 MHz Public/Private Partnership § 90.1410 Network sharing agreement... related entities as the Commission may require or allow will be governed by the Network Sharing Agreement...

  7. A Wireless Communications Laboratory on Cellular Network Planning

    ERIC Educational Resources Information Center

    Dawy, Z.; Husseini, A.; Yaacoub, E.; Al-Kanj, L.

    2010-01-01

    The field of radio network planning and optimization (RNPO) is central for wireless cellular network design, deployment, and enhancement. Wireless cellular operators invest huge sums of capital on deploying, launching, and maintaining their networks in order to ensure competitive performance and high user satisfaction. This work presents a lab…

  8. The deep space network, Volume 11

    NASA Technical Reports Server (NTRS)

    1972-01-01

    Deep Space Network progress in flight project support, Tracking and Data Acquisition research and technology, network engineering, hardware and software implementation, and operations are presented. Material is presented in each of the following categories: description of DSN; mission support; radio science; support research and technology; network engineering and implementation; and operations and facilities.

  9. 47 CFR 90.1410 - Network sharing agreement.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 47 Telecommunication 5 2012-10-01 2012-10-01 false Network sharing agreement. 90.1410 Section 90... PRIVATE LAND MOBILE RADIO SERVICES 700 MHz Public/Private Partnership § 90.1410 Network sharing agreement... related entities as the Commission may require or allow will be governed by the Network Sharing Agreement...

  10. Mental health network governance: comparative analysis across Canadian regions

    PubMed Central

    Wiktorowicz, Mary E; Fleury, Marie-Josée; Adair, Carol E; Lesage, Alain; Goldner, Elliot; Peters, Suzanne

    2010-01-01

    Objective Modes of governance were compared in ten local mental health networks in diverse contexts (rural/urban and regionalized/non-regionalized) to clarify the governance processes that foster inter-organizational collaboration and the conditions that support them. Methods Case studies of ten local mental health networks were developed using qualitative methods of document review, semi-structured interviews and focus groups that incorporated provincial policy, network and organizational levels of analysis. Results Mental health networks adopted either a corporate structure, mutual adjustment or an alliance governance model. A corporate structure supported by regionalization offered the most direct means for local governance to attain inter-organizational collaboration. The likelihood that networks with an alliance model developed coordination processes depended on the presence of the following conditions: a moderate number of organizations, goal consensus and trust among the organizations, and network-level competencies. In the small and mid-sized urban networks where these conditions were met their alliance realized the inter-organizational collaboration sought. In the large urban and rural networks where these conditions were not met, externally brokered forms of network governance were required to support alliance based models. Discussion In metropolitan and rural networks with such shared forms of network governance as an alliance or voluntary mutual adjustment, external mediation by a regional or provincial authority was an important lever to foster inter-organizational collaboration. PMID:21289999

  11. World scientific collaboration in coronary heart disease research.

    PubMed

    Yu, Qi; Shao, Hongfang; He, Peifeng; Duan, Zhiguang

    2013-08-10

    Coronary heart disease (CHD) will continue to exert a heavy burden for countries all over the world. Scientific collaboration has become the only choice for progress in biomedicine. Unfortunately, there is a scarcity of scientific publications about scientific collaboration in CHD research. This study examines collaboration behaviors across multiple collaboration types in the CHD research. 294,756 records about CHD were retrieved from Web of Science. Methods such as co-authorship, social network analysis, connected component, cliques, and betweenness centrality were used in this study. Collaborations have increased at the author, institution and country/region levels in CHD research over the past three decades. 3000 most collaborative authors, 572 most collaborative institutions and 52 countries/regions are extracted from their corresponding collaboration network. 766 cliques are found in the most collaborative authors. 308 cliques are found in the most collaborative institutions. Western countries/regions represent the core of the world's collaboration. The United States ranks first in terms of number of multi-national publications, while Hungary leads in the ranking measured by their proportion of collaborative output. The rate of economic development in the countries/regions also affects the multi-national collaboration behavior. Collaborations among countries/regions need to be encouraged in the CHD research. The visualization of overlapping cliques in the most collaborative authors and institutions are considered "skeleton" of the collaboration network. Eastern countries/regions should strengthen cooperation with western countries/regions in the CHD research. Copyright © 2012 Elsevier Ireland Ltd. All rights reserved.

  12. Advanced wireless mobile collaborative sensing network for tactical and strategic missions

    NASA Astrophysics Data System (ADS)

    Xu, Hao

    2017-05-01

    In this paper, an advanced wireless mobile collaborative sensing network will be developed. Through properly combining wireless sensor network, emerging mobile robots and multi-antenna sensing/communication techniques, we could demonstrate superiority of developed sensing network. To be concrete, heterogeneous mobile robots including unmanned aerial vehicle (UAV) and unmanned ground vehicle (UGV) are equipped with multi-model sensors and wireless transceiver antennas. Through real-time collaborative formation control, multiple mobile robots can team the best formation that can provide most accurate sensing results. Also, formatting multiple mobile robots can also construct a multiple-input multiple-output (MIMO) communication system that can provide a reliable and high performance communication network.

  13. Collaboration Nation: The Building of the Welsh Repository Network

    ERIC Educational Resources Information Center

    Knowles, Jacqueline

    2010-01-01

    Purpose: The purpose of this paper is to disseminate information about the Welsh Repository Network (WRN), innovative work being undertaken to build an integrated network of institutional digital repositories. A collaborative approach, in particular through the provision of centralised technical and organisational support, has demonstrated…

  14. "SWING": A European project for a new application of an ionospheric network

    NASA Astrophysics Data System (ADS)

    Zolesi, B.; Bianchi, C.; Meloni, A.; Baskaradas, J. A.; Belehaki, A.; Altadill, D.; Dalle Mese, E.

    2016-05-01

    The SWING (Short Wave critical Infrastructure Network based on a new Generation high survival radio communication system) is a European project aimed at studying a high survival high-frequency (HF) radio network to link European Critical Infrastructures (ECIs). This system is thought to replace broadband internet communication, maintaining the minimum flux of essential information for the ECIs management and control, in case of wide-scale threats, including terrorist attacks, able to put out of order internet links over the Mediterranean region. SWING is designed to evaluate the threat and increase the security awareness, as well as the level of protection, of analogous and/or interdependent ECIs. In order to meet these goals, SWING was finalized to recognize how and when the internet communication fails and to develop the standard software and hardware tools necessary for implementing communication protocols suited for a reliable and interoperable short-wave (SW) or high-frequency (HF) radio network backup. The internet broadband description and internet failure recognition were taken into consideration in the project but are not treated in this paper. It has been assessed that in case of complete failure of the internet broadband communication fundamental information for the management and control of ECIs over the Mediterranean region can be maintained with a HF network, even in case of moderate ionospheric perturbations.

  15. The history of radio telescopes, 1945-1990

    NASA Astrophysics Data System (ADS)

    Sullivan, Woodruff T.

    2009-08-01

    Forged by the development of radar during World War II, radio astronomy revolutionized astronomy during the decade after the war. A new universe was revealed, centered not on stars and planets, but on the gas between the stars, on explosive sources of unprecedented luminosity, and on hundreds of mysterious discrete sources with no optical identifications. Using “radio telescopes” that looked nothing like traditional (optical) telescopes, radio astronomers were a very different breed from traditional (optical) astronomers. This pathbreaking of radio astronomy also made it much easier for later “astronomies” and their “telescopes” (X-ray, ultraviolet, infrared, gamma-ray) to become integrated into astronomy after the launch of the space age in the 1960s. This paper traces the history of radio telescopes from 1945 through about 1990, from the era of converted small-sized, military radar antennas to that of large interferometric arrays connected by complex electronics and computers; from the era of strip-chart recordings measured by rulers to powerful computers and display graphics; from the era of individuals and small groups building their own equipment to that of Big Science, large collaborations and national observatories.

  16. Culture, Role and Group Work: A Social Network Analysis Perspective on an Online Collaborative Course

    ERIC Educational Resources Information Center

    Stepanyan, Karen; Mather, Richard; Dalrymple, Roger

    2014-01-01

    This paper discusses the patterns of network dynamics within a multicultural online collaborative learning environment. It analyses the interaction of participants (both students and facilitators) within a discussion board that was established as part of a 3-month online collaborative course. The study employs longitudinal probabilistic social…

  17. Burning through organizational boundaries? Examining inter-organizational communication networks in policy-mandated collaborative bushfire planning groups

    Treesearch

    Rachel F. Brummel; Kristen C. Nelson; Pamela J. Jakes

    2012-01-01

    Collaboration can enhance cooperation across geographic and organizational scales, effectively "burning through" those boundaries. Using structured social network analysis (SNA) and qualitative in-depth interviews, this study examined three collaborative bushfire planning groups in New South Wales, Australia and asked: How does participation in policy-...

  18. Australian radio observations of SN1987A - A progress report

    NASA Technical Reports Server (NTRS)

    Reynolds, John E.; Jauncey, David L.; Preston, Robert A.; Mutel, Robert L.; Livermore, R. W.

    1987-01-01

    Regular monitoring of SN 1987A in the radio spectrum is being conducted at a number of Australian observatories. Although no emission is detectable at present, a VLBI network has been established to map a possible major outburst at high resolution.

  19. Ground wave emergency network final operational capability: Environmental assessment for northwestern Nebraska relay node, site number RN 8C930NE

    NASA Astrophysics Data System (ADS)

    1993-02-01

    The Ground Wave Emergency Network (GWEN) is a radio communication system designed to relay emergency messages between strategic military areas in the continental United States. The system is immune to the effects of high-altitude electromagnetic pulse (HEMP) energy surges caused by nuclear bursts in the ionosphere that would disrupt conventional communications equipment such as telephones and shortwave radios. A failure of such equipment would prevent timely communications among top military and civilian leaders and strategic Air Force locations and prevent U.S. assessment and retaliation during an attack. GWEN is an essential part of a defense modernization program to upgrade and improve our nation's communications system, thereby strengthening deterrence. The GWEN system consists of a network of relay nodes, receive-only stations, and input/output stations. Each relay node, such as the one proposed in northwestern Nebraska, consists of a guyed radio tower facility similar to those used by commercial AM broadcast transmitters.

  20. Ground wave emergency network environmental assessment for northwestern Colorado relay node site number RN 8C924CO

    NASA Astrophysics Data System (ADS)

    1993-02-01

    The Ground Wave Emergency Network (GWEN) is a radio communication system designed to relay emergency messages between strategic military areas in the continental United States. The system is immune to the effects of high-altitude electromagnetic pulse (HEMP) energy surges caused by nuclear bursts in the ionosphere that would disrupt conventional communications equipment such as telephones and shortwave radios. A failure of such equipment would prevent timely communications among top military and civilian leaders and strategic Air Force locations and prevent U.S. assessment and retaliation during an attack. GWEN is an essential part of a defense modernization program to upgrade and improve our nation's communications system, thereby strengthening deterrence. The GWEN system consists of a network of relay nodes, receive-only stations, and input/output stations. Each relay node, such as the one proposed in southern Nevada consists of a guyed radio tower facility similar to those used by commercial AM broadcast transmitters.

  1. Ground wave emergency network final operational capability: Environmental assessment for southern Nevada relay node site number RN 8W918NV

    NASA Astrophysics Data System (ADS)

    1993-03-01

    The Ground Wave Emergency Network (GWEN) is a radio communication system designed to relay emergency messages between strategic military areas in the continental United States. The system is immune to the effects of high-altitude electromagnetic pulse (HEMP) energy surges caused by nuclear bursts in the ionosphere that would disrupt conventional communications equipment such as telephones and shortwave radios. A failure of such equipment would prevent timely communications among top military and civilian leaders and strategic Air Force locations and prevent U.S. assessment and retaliation during an attack. GWEN is an essential part of a defense modernization program to upgrade and improve our nation's communications system, thereby strengthening deterrence. The GWEN system consists of a network of relay nodes, receive-only stations, and input/output stations. Each relay node, such as the one proposed in southern Nevada consists of a guyed radio tower facility similar to those used by commercial AM broadcast transmitters.

  2. Creatiing a Collaborative Research Network for Scientists

    NASA Astrophysics Data System (ADS)

    Gunn, W.

    2012-12-01

    This abstract proposes a discussion of how professional science communication and scientific cooperation can become more efficient through the use of modern social network technology, using the example of Mendeley. Mendeley is a research workflow and collaboration tool which crowdsources real-time research trend information and semantic annotations of research papers in a central data store, thereby creating a "social research network" that is emergent from the research data added to the platform. We describe how Mendeley's model can overcome barriers for collaboration by turning research papers into social objects, making academic data publicly available via an open API, and promoting more efficient collaboration. Central to the success of Mendeley has been the creation of a tool that works for the researcher without the requirement of being part of an explicit social network. Mendeley automatically extracts metadata from research papers, and allows a researcher to annotate, tag and organize their research collection. The tool integrates with the paper writing workflow and provides advanced collaboration options, thus significantly improving researchers' productivity. By anonymously aggregating usage data, Mendeley enables the emergence of social metrics and real-time usage stats on top of the articles' abstract metadata. In this way a social network of collaborators, and people genuinely interested in content, emerges. By building this research network around the article as the social object, a social layer of direct relevance to academia emerges. As science, particularly Earth sciences with their large shared resources, become more and more global, the management and coordination of research is more and more dependent on technology to support these distributed collaborations.

  3. Improving collaboration between Primary Care Research Networks using Access Grid technology.

    PubMed

    Nagykaldi, Zsolt; Fox, Chester; Gallo, Steve; Stone, Joseph; Fontaine, Patricia; Peterson, Kevin; Arvanitis, Theodoros

    2008-01-01

    Access Grid (AG) is an Internet2-driven, high performance audio-visual conferencing technology used worldwide by academic and government organisations to enhance communication, human interaction and group collaboration. AG technology is particularly promising for improving academic multi-centre research collaborations. This manuscript describes how the AG technology was utilised by the electronic Primary Care Research Network (ePCRN) that is part of the National Institutes of Health (NIH) Roadmap initiative to improve primary care research and collaboration among practice-based research networks (PBRNs) in the USA. It discusses the design, installation and use of AG implementations, potential future applications, barriers to adoption, and suggested solutions.

  4. Cognitive and Social Structure of the Elite Collaboration Network of Astrophysics: A Case Study on Shifting Network Structures

    ERIC Educational Resources Information Center

    Heidler, Richard

    2011-01-01

    Scientific collaboration can only be understood along the epistemic and cognitive grounding of scientific disciplines. New scientific discoveries in astrophysics led to a major restructuring of the elite network of astrophysics. To study the interplay of the epistemic grounding and the social network structure of a discipline, a mixed-methods…

  5. A Social Network Analysis of Teaching and Research Collaboration in a Teachers' Virtual Learning Community

    ERIC Educational Resources Information Center

    Lin, Xiaofan; Hu, Xiaoyong; Hu, Qintai; Liu, Zhichun

    2016-01-01

    Analysing the structure of a social network can help us understand the key factors influencing interaction and collaboration in a virtual learning community (VLC). Here, we describe the mechanisms used in social network analysis (SNA) to analyse the social network structure of a VLC for teachers and discuss the relationship between face-to-face…

  6. The Telecommunications and Data Acquisition Report

    NASA Technical Reports Server (NTRS)

    Posner, Edward C. (Editor)

    1993-01-01

    Reports on developments in programs managed by JPL's Office of Telecommunications and Data Acquisition (TDA) are provided. In space communications, radio navigation, radio science, and ground-based radio and radar astronomy, it reports on activities of the Deep Space Network (DSN) in planning, supporting research and technology, implementation, and operations. Also included are standards activity at JPL for space data and information systems and reimbursable DSN work performed for other agencies through NASA.

  7. The Telecommunications and Data Acquisition Report

    NASA Technical Reports Server (NTRS)

    Yuen, Joseph H. (Editor)

    1994-01-01

    Reports on developments in programs managed by JPL's Office of Telecommunications and Data Acquisition (TDA) are provided. In space communications, radio navigation, radio science, and ground-based radio and radar astronomy, it reports on activities of the Deep Space Network (DSN) in planning, supporting research and technology, implementation, and operations. Also included are standards activity at JPL for space data and information systems and reimbursable DSN work performed for other agencies through NASA.

  8. Proactive Time-Rearrangement Scheme for Multi-Radio Collocated Platform

    NASA Astrophysics Data System (ADS)

    Kim, Chul; Shin, Sang-Heon; Park, Sang Kyu

    We present a simple proactive time rearrangement scheme (PATRA) that reduces the interferences from multi-radio devices equipped in one platform and guarantees user-conceived QoS. Simulation results show that the interference among multiple radios in one platform causes severe performance degradation and cannot guarantee the user requested QoS. However, the PATRA can dramatically improve not only the userconceived QoS but also the overall network throughput.

  9. Extremely Bendable, High-Performance Integrated Circuits Using Semiconducting Carbon Nanotube Networks for Digital, Analog, and Radio-Frequency Applications

    DTIC Science & Technology

    2012-02-07

    circuits on mechanically flexible substrates for digital, analog and radio frequency applications. The asobtained thin-film transistors ( TFTs ) exhibit... flexible substrates for digital, analog and radio frequency applications. The as- obtained thin-film transistors ( TFTs ) exhibit highly uniform device...LCD) and organic light- emitting diode ( OLED ) displays lack the transparency and flexibility and are thus unsuitable for flexible electronic

  10. The Telecommunications and Data Acquisition Report

    NASA Technical Reports Server (NTRS)

    Posner, E. C. (Editor)

    1987-01-01

    Archival reports on developments in programs managed by JPL's Office of Telecommunications and Data Acquisition (TDA) are provided. Activities of the Deep Space Network (DSN) in space communications, radio navigation, radio science, and ground-based radio astronomy are reported. Also included are the plans, supporting research and technology, implementation and operations for the Ground Communications Facility (GCF). In geodynamics, the publication reports on the application of radio interferometry at microwave frequencies for geodynamic measurements. In the search for extraterrestrial intelligence (SETI), it reports on implementation and operations for searching the microwave spectrum.

  11. Utilization-Based Modeling and Optimization for Cognitive Radio Networks

    NASA Astrophysics Data System (ADS)

    Liu, Yanbing; Huang, Jun; Liu, Zhangxiong

    The cognitive radio technique promises to manage and allocate the scarce radio spectrum in the highly varying and disparate modern environments. This paper considers a cognitive radio scenario composed of two queues for the primary (licensed) users and cognitive (unlicensed) users. According to the Markov process, the system state equations are derived and an optimization model for the system is proposed. Next, the system performance is evaluated by calculations which show the rationality of our system model. Furthermore, discussions among different parameters for the system are presented based on the experimental results.

  12. Coding for spread spectrum packet radios

    NASA Technical Reports Server (NTRS)

    Omura, J. K.

    1980-01-01

    Packet radios are often expected to operate in a radio communication network environment where there tends to be man made interference signals. To combat such interference, spread spectrum waveforms are being considered for some applications. The use of convolutional coding with Viterbi decoding to further improve the performance of spread spectrum packet radios is examined. At 0.00001 bit error rates, improvements in performance of 4 db to 5 db can easily be achieved with such coding without any change in data rate nor spread spectrum bandwidth. This coding gain is more dramatic in an interference environment.

  13. Overload Control for Signaling Congestion of Machine Type Communications in 3GPP Networks

    PubMed Central

    Lu, Zhaoming; Pan, Qi; Wang, Luhan; Wen, Xiangming

    2016-01-01

    Because of the limited resources on radio access channels of third generation partnership projection (3GPP) network, one of the most challenging tasks posted by 3GPP cellular-based machine type communications (MTC) is congestion due to massive requests for connection to radio access network (RAN). In this paper, an overload control algorithm in 3GPP RAN is proposed, which proactively disperses the simultaneous access attempts in evenly distributed time window. Through periodic reservation strategy, massive access requests of MTC devices are dispersed in time, which reduces the probability of confliction of signaling. By the compensation and prediction mechanism, each device can communicate with MTC server with dynamic load of air interface. Numerical results prove that proposed method makes MTC applications friendly to 3GPP cellular network. PMID:27936011

  14. Overload Control for Signaling Congestion of Machine Type Communications in 3GPP Networks.

    PubMed

    Lu, Zhaoming; Pan, Qi; Wang, Luhan; Wen, Xiangming

    2016-01-01

    Because of the limited resources on radio access channels of third generation partnership projection (3GPP) network, one of the most challenging tasks posted by 3GPP cellular-based machine type communications (MTC) is congestion due to massive requests for connection to radio access network (RAN). In this paper, an overload control algorithm in 3GPP RAN is proposed, which proactively disperses the simultaneous access attempts in evenly distributed time window. Through periodic reservation strategy, massive access requests of MTC devices are dispersed in time, which reduces the probability of confliction of signaling. By the compensation and prediction mechanism, each device can communicate with MTC server with dynamic load of air interface. Numerical results prove that proposed method makes MTC applications friendly to 3GPP cellular network.

  15. A Novel Cost-effective OFDM WDM-PON Radio Over Fiber System Employing FBG to Generate Optical mm-wave

    NASA Astrophysics Data System (ADS)

    Nguyen, HoangViet

    2015-03-01

    We have investigated and demonstrated a novel scheme to generate 2.5 Gbit/s 64 QAM orthogonal frequency division multiplexing (OFDM) signals for Radio Over Fiber (ROF) systems. We employ Fiber Bragg Grating (FBG) because the repetitive frequency of the RF source and the bandwidth of the optical modulator are largely reduced and the architecture of the ROF system is simpler. Wavelength-Division-Multiplexed Passive Optical Network (WDM-PON) has been considered as a promising solution for future broadband access networks. Principle of WDM-PON access network compatible with OFDM-ROF systems is investigated. This novel scheme which has multiple double-frequency technique to generate mm-wave signal to carry OFDM signals is a practical scheme to be applied for future broadband access networks.

  16. Efficient Delivery and Visualization of Long Time-Series Datasets Using Das2 Tools

    NASA Astrophysics Data System (ADS)

    Piker, C.; Granroth, L.; Faden, J.; Kurth, W. S.

    2017-12-01

    For over 14 years the University of Iowa Radio and Plasma Wave Group has utilized a network transparent data streaming and visualization system for most daily data review and collaboration activities. This system, called Das2, was originally designed in support of the Cassini Radio and Plasma Wave Science (RPWS) investigation, but is now relied on for daily review and analysis of Voyager, Polar, Cluster, Mars Express, Juno and other mission results. In light of current efforts to promote automatic data distribution in space physics it seems prudent to provide an overview of our open source Das2 programs and interface definitions to the wider community and to recount lessons learned. This submission will provide an overview of interfaces that define the system, describe the relationship between the Das2 effort and Autoplot and will examine handling Cassini RPWS Wideband waveforms and dynamic spectra as examples of dealing with long time-series data sets. In addition, the advantages and limitations of the current Das2 tool set will be discussed, as well as lessons learned that are applicable to other data sharing initiatives. Finally, plans for future developments including improved catalogs to support 'no-software' data sources and redundant multi-server fail over, as well as new adapters for CSV (Comma Separated Values) and JSON (Javascript Object Notation) output to support Cassini closeout and the HAPI (Heliophysics Application Programming Interface) initiative are outlined.

  17. Dynamics of a Global Zoonotic Research Network Over 33 Years (1980-2012).

    PubMed

    Hossain, Liaquat; Karimi, Faezeh; Wigand, Rolf T

    2015-10-01

    The increasing rate of outbreaks in humans of zoonotic diseases requires detailed examination of the education, research, and practice of animal health and its connection to human health. This study investigated the collaboration network of different fields engaged in conducting zoonotic research from a transdisciplinary perspective. Examination of the dynamics of this network for a 33-year period from 1980 to 2012 is presented through the development of a large scientometric database from Scopus. In our analyses we compared several properties of these networks, including density, clustering coefficient, giant component, and centrality measures over time. We also elicited patterns in different fields of study collaborating with various other fields for zoonotic research. We discovered that the strongest collaborations across disciplines are formed among the fields of medicine; biochemistry, genetics, and molecular biology; immunology and microbiology; veterinary; agricultural and biological sciences; and social sciences. Furthermore, the affiliation network is growing overall in terms of collaborative research among different fields of study such that more than two-thirds of all possible collaboration links among disciplines have already been formed. Our findings indicate that zoonotic research scientists in different fields (human or animal health, social science, earth and environmental sciences, engineering) have been actively collaborating with each other over the past 11 years.

  18. Research Networks Map | Division of Cancer Prevention

    Cancer.gov

    The Division of Cancer Prevention supports major scientific collaborations and research networks at more than 100 sites across the United States. Seven Major Programs' sites are shown on this map. | The Division of Cancer Prevention supports major scientific collaborations and research networks at more than 100 sites across the United States.

  19. Social Networks, Communication Styles, and Learning Performance in a CSCL Community

    ERIC Educational Resources Information Center

    Cho, Hichang; Gay, Geri; Davidson, Barry; Ingraffea, Anthony

    2007-01-01

    The aim of this study is to empirically investigate the relationships between communication styles, social networks, and learning performance in a computer-supported collaborative learning (CSCL) community. Using social network analysis (SNA) and longitudinal survey data, we analyzed how 31 distributed learners developed collaborative learning…

  20. Computer Networking Strategies for Building Collaboration among Science Educators.

    ERIC Educational Resources Information Center

    Aust, Ronald

    The development and dissemination of science materials can be associated with technical delivery systems such as the Unified Network for Informatics in Teacher Education (UNITE). The UNITE project was designed to investigate ways for using computer networking to improve communications and collaboration among university schools of education and…

  1. Why a Transatlantic Network? Some Thoughts on Feasibility and Effectiveness.

    ERIC Educational Resources Information Center

    Hooghoff, Hans

    Despite the phenomenon of cooperation and collaboration between and among nations in many areas, networks for the benefit of education are nearly nonexistent in Western Europe. A "network" means the collaboration between educational institutions in the field of curriculum development, training, research, dissemination, transfer, and implementation…

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

    PubMed

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

    2014-12-01

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

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

    NASA Astrophysics Data System (ADS)

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

    2013-04-01

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

  4. Risk management communication system between a local government and residents using several network systems and terminal devices

    NASA Astrophysics Data System (ADS)

    Ohyama, Takashi; Enomoto, Hiroyuki; Takei, Yuichiro; Maeda, Yuji

    2009-05-01

    Most of Japan's local governments utilize municipal disaster-management radio communications systems to communicate information on disasters or terrorism to residents. The national government is progressing in efforts toward digitalization by local governments of these systems, but only a small number (approx. 10%) have introduced such equipment due to its requiring large amounts of investment. On the other hand, many local governments are moving forward in installation of optical fiber networks for the purpose of eliminating the "digital divide." We herein propose a communication system as an alternative or supplement to municipal disaster-management radio communications systems, which utilizes municipal optical fiber networks, the internet and similar networks and terminals. The system utilizes the multiple existing networks and is capable of instantly distributing to all residents, and controlling, risk management information. We describe the system overview and the field trials conducted with a local government using this system.

  5. Scientific collaboration and endorsement: Network analysis of coauthorship and citation networks

    PubMed Central

    Ding, Ying

    2010-01-01

    Scientific collaboration and endorsement are well-established research topics which utilize three kinds of methods: survey/questionnaire, bibliometrics, and complex network analysis. This paper combines topic modeling and path-finding algorithms to determine whether productive authors tend to collaborate with or cite researchers with the same or different interests, and whether highly cited authors tend to collaborate with or cite each other. Taking information retrieval as a test field, the results show that productive authors tend to directly coauthor with and closely cite colleagues sharing the same research interests; they do not generally collaborate directly with colleagues having different research topics, but instead directly or indirectly cite them; and highly cited authors do not generally coauthor with each other, but closely cite each other. PMID:21344057

  6. Radio diagnostics and analysis on the Puerto Rico CubeSat

    NASA Astrophysics Data System (ADS)

    Bergman, J. E. S.; Bruhn, F.; Isham, B.; Rincon-Charris, A.

    2014-04-01

    The Puerto Rico CubeSat is a collaboration between Interamerican University of Puerto Rico, the University of Puerto Rico, the Ana G. Ḿendez University System, NASA Marshal Space Flight Center, the University of Alabama at Huntsville, the Swedish Institute of Space Physics, and M¨alardalens University. Principle goals include providing aerospace and systems engineering experiences to students at the participating institutions. Mission objectives include the acquisition of space weather data to aid in better understanding the Sun to Earth connection. The Puerto Rico Cube- Sat is a 3U configuration, 10 × 10 × 30 cm. Active attitude control will be used to align the long (3U) axis along the orbital path, and the satellite will rotate along the 3U axis to assist in thermal management. The Puerto Rico CubeSat will carry two scientific payloads. One is CARLO (Charge Analyzer Responsive to Local Oscillation), which is designed to measure ion turbulence from 0 to 10 kHz. CARLO will operate in a ram configuration, thus giving it the ability to distinguish between ambient and spacecraftinduced irregularities in plasma density. The second payload is GIMMERF, a 0 to 30 MHz radio instrument, consisting of a digital 4-channel direct sampling receiver board, atmospheric-noise-limited preamplifiers, and four electrically short monopole antennas. The antennas are connected electronically, as dipoles, to enable measurements of the full 3-dimensional electric field vector signal, which, in turn makes it possible to characterize the radio emissions in terms of Stokes parameters and to perform direction finding. GIMME-RF will use artificial neural network technology to automatically identify radio data of interest. All radio data will be downloaded at 1% time resolution, and radio data of special interest (automatically identified or human selected) will be downloaded at full time and frequency resolution. CARLO and GIMME-RF are complementary instruments, as CARLO will measure low-frequency plasma turbulence, which affects radio propagation in the high-frequency radio band. The satellite communications system 1 EPSC Abstracts Vol. 9, EPSC2014-799, 2014 European Planetary Science Congress 2014 c Author(s) 2014 EPSC European Planetary Science Congress will operate at frequencies between 902 and 928 MHz and will share the same antenna used by GIMME-RF. The Puerto Rico CubeSat is expected to be ready for launch in 2016; a launch vehicle has not yet been identified. Support for the Puerto Rico Cubesat comes from the Puerto Rico Industrial Development Company (PRIDCO), the Puerto Rico NASA Experimental Program to Stimulate Competitive Research (EPSCoR), and the Interamerican University of Puerto Rico Bayaḿon Campus. The GIMMERF payload is supported by the Swedish National Space Board (SNSB), with in-kind contributions from Ḿalardalen's University and the Swedish Institute of Space Physics.

  7. Topology Control and Routing in Ad Hoc Networks

    NASA Astrophysics Data System (ADS)

    Carr-Motyckova, Lenka; Navarra, Alfredo; Johansson, Tomas; Unger, Walter

    Mobile nodes with the ability to communicate with radio signals may form an ad hoc network. In this chapter special problems arising for these ad hoc networks are considered. These include range control, the reduction of interferences, regulation of power consumption, and localization.

  8. The Comet Halley archive: Summary volume

    NASA Technical Reports Server (NTRS)

    Sekanina, Zdenek (Editor); Fry, Lori (Editor)

    1991-01-01

    The contents are as follows: The Organizational History of the International Halley Watch; Operations of the International Halley Watch from a Lead Center Perspective; The Steering Group; Astrometry Network; Infrared Studies Network; Large-Scale Phenomena Network; Meteor Studies Network; Near-Nucleus Studies Network; Photometry and Polarimetry Network; Radio Science Network; Spectroscopy and Spectrophotometry Network; Amateur Observation Network; Use of the CD-ROM Archive; The 1986 Passage of Comet Halley; and Recent Observations of Comet Halley.

  9. The telecommunications and data acquisition report

    NASA Technical Reports Server (NTRS)

    Renzetti, N. A. (Editor)

    1982-01-01

    Progress in the development and operations of the Deep Space Network is reported. Developments in Earth-based radio technology as applied to other research programs are also reported. These programs include geodynamics, astrophysics, and radio searching for extraterrestrial intelligence in the microwave region of the electromagnetic spectrum.

  10. The Telecommunications and Data Acquisition report

    NASA Technical Reports Server (NTRS)

    Renzetti, N. A. (Editor)

    1981-01-01

    Progress in the development and operations of the Deep Space Network is reported including develoments in Earth-based radio technology as applied to other research programs. These programs are: geodynamics, astrophysics, and the radio search for extraterrestrial intelligence in the microwave region of the electromagnetic spectrum.

  11. The Value of Trainee Networks in Pediatric Surgical Research.

    PubMed

    Skerritt, Clare; Hall, Nigel J

    2015-12-01

    In 2007, the first trainee-led surgical research network was founded in the United Kingdom (UK). The West Midlands Research Collaborative was started by a group of enthusiastic adult surgical trainees who saw the benefits of altruistic collaboration to generate high quality, multicenter research. Seeing the success of their research projects, including randomized controlled trials, trainees in other regions and specialties were spurred on to founding their own research collaboratives. The Pediatric Surgical Trainee Research Network was started in 2011 by a group of UK trainees with the aim to promote, facilitate, and encourage trainee-led research in pediatric surgery. This article summarizes the history and evolution of the trainee collaborative surgical research. It examines the challenges which multicenter research entails and the steps the collaboratives have taken to overcome them. We describe some of the projects which have been successfully completed and the benefits that the trainee networks have for patients and surgeons alike. Georg Thieme Verlag KG Stuttgart · New York.

  12. Perspectives of intellectual processing of large volumes of astronomical data using neural networks

    NASA Astrophysics Data System (ADS)

    Gorbunov, A. A.; Isaev, E. A.; Samodurov, V. A.

    2018-01-01

    In the process of astronomical observations vast amounts of data are collected. BSA (Big Scanning Antenna) LPI used in the study of impulse phenomena, daily logs 87.5 GB of data (32 TB per year). This data has important implications for both short-and long-term monitoring of various classes of radio sources (including radio transients of different nature), monitoring the Earth’s ionosphere, the interplanetary and the interstellar plasma, the search and monitoring of different classes of radio sources. In the framework of the studies discovered 83096 individual pulse events (in the interval of the study highlighted July 2012 - October 2013), which may correspond to pulsars, twinkling springs, and a rapid radio transients. Detected impulse events are supposed to be used to filter subsequent observations. The study suggests approach, using the creation of the multilayered artificial neural network, which processes the input raw data and after processing, by the hidden layer, the output layer produces a class of impulsive phenomena.

  13. MSAT: A booster for land based mobile radiocommunication networks?

    NASA Technical Reports Server (NTRS)

    Boulay, Guy

    1990-01-01

    It is demonstrated that the foreseen phenomenal growth of mobilesat services will impact positively existing terrestrial mobile radio services. Mobilesat systems will not displace the existing terrestrial market in the near future, partly due to the high cost of their terminal units and associated airtime, but also due to some technical limitations, such as lack of spectrum efficiency and high susceptibility to shadowing. However, the ubiquity of mobilesat services will open new market to terrestrial radio technologies. The latter is expected to be the most economical way of extending locally mobilesat services to many users. Conversely, mobilesat systems will be used to extend the capabilities of terrestrial radio systems in areas where the former cannot be implemented cost effectively. It is believed that terrestrial mobile network operators using these service extension capabilities will have a competitive advantage over those who do not. Overall, it is expected that emerging mobilesat services, far from being a threat to terrestrial radio systems, will rather provide these with numerous opportunities of incrementing their base market.

  14. Advanced teleprocessing systems

    NASA Astrophysics Data System (ADS)

    Kleinrock, L.; Gerla, M.

    1983-03-01

    This Semi-Annual Technical Report covers research covering the period from October 1, 1982 to March 31, 1983. This contract has three primary designated research areas: packet radio systems, resource sharing and allocation, and distributed processing and control. This report contains abstracts of publications which summarize research results in these areas followed by the main body of the report which is devoted to a treatment of single- and multi-hop packet radio systems. In particular, the main body consists of a Ph.D. dissertation, Analysis of Throughput and Delay for Single- and Multi-Hop Packet Radio Networks. The work presents a new approach to evaluating the performance of multi-hop packet radio networks, namely, a study of the times between successful transmissions. Also studied is the behavior of packets in a multi-hop system when a fixed transmission radius is specified and this radius is then optimized for throughput. A Markov chain model is also introduced and solved numerically to evaluate transmission and flow control strategies in these systems.

  15. A Statewide Private Microwave Wide Area Network for Real-time Natural Hazard Monitoring

    NASA Astrophysics Data System (ADS)

    Williams, M. C.; Kent, G.; Smith, K. D.; Plank, G.; Slater, D.; Torrisi, J.; Presser, R.; Straley, K.

    2013-12-01

    The Nevada Seismological Laboratory (NSL) at the University of Nevada, Reno, operates the Nevada Seismic Network, a collection of ground motion instruments installed throughout Nevada and California, for the purposes of detecting, locating, and notifying the public of earthquakes in the state. To perform these tasks effectively, NSL has designed and built a statewide wireless microwave wide-area network (WAN) in order to receive ground motion data in near real-time. This network consists of radio access points, backhauls, and backbone communication sites transmitting time-series, images, and datalogger diagnostics to our data center servers in Reno. This privately managed communication network greatly reduces the dependence on third-party infrastructure (e.g. commercial cellular networks), and is vital for emergency management response and system uptime. Any individual seismograph or data collection device is networked through a wireless point-to-multipoint connection to a remote access point (AP) using a low-cost radio/routerboard combination. Additional point-to-point connections from AP's to radio backhauls and/or mountaintop backbone sites allow the Data Center in Reno to communicate with and receive data directly from each datalogger. Dataloggers, radios, and routers can be configured using tablets on-site, or via desktop computers at the Data Center. Redundant mountaintop links can be added to the network and facilitate the re-routing of data (similar to a meshed network) in the event of a faulty, failing, or noisy communication site. All routers, radios, and servers, including those at the Data Center, have redundant power and can operate independently in the event of a grid power or public Internet outage. A managed server room at the Data Center processes earthquake data for notifications and acts as a data source for remote users. Consisting of about 500 hosts, and spanning hundreds of miles, this WAN provides network operators access to each router and datalogger in our seismic network not only for data collection, but also for maintenance and quality control. This has resulted in several partnerships with other agencies. In addition to our seismic station network for earthquake monitoring, we currently manage ~400 more channels of data (many running at 500 Hz) for the National Center for Nuclear Security (NCNS) Source Physics Experiments, a series of chemical explosions at the Nevada National Security Site. Some of our mountaintop stations have been experimentally equipped with near-infrared high-definition fire cameras for wildfire monitoring, and have recently recorded the Bison and Pedlar fires in northwest Nevada. Data for the Nevada EPSCor climate program also utilizes the NSL WAN. Real-time access to data for these experiments greatly reduces the effort required for data archival, quality control, and monitoring equipment failures. Future plans include increasing density of stations in urban areas such as Reno and Las Vegas, and expanding coverage to Tahoe and eastern Nevada.

  16. A Strategic Independent Geodetic VLBI Network for Europe

    NASA Astrophysics Data System (ADS)

    Dale, Denise; Combrinck, Ludwig; de Witt, Alet

    2014-12-01

    Irregularities of the rotation of the Earth in space are described by the Earth Orientation Parameters (EOPs). An independent EOP network, applying the Very Long Baseline Interferometry (VLBI) technique and using the Vienna VLBI Software (VieVS), are strategically essential for Europe to minimize its reliance on foreign global support in terms of required infrastructure for the realization of such a network. The generation of independent EOPs is already achievable by countries such as the USA, the People's Republic of China, and the Russian Federation due to their large extent of land mass that allows for long baselines in both the North-South and East-West directions and thus allows for accurate determination of all EOPs. These three countries need not rely on foreign partnerships to generate EOPs, as they all have independent geodetic VLBI networks capable of determining EOPs for precise positioning, navigation, and satellite launch/orbital purposes. They also have or are developing independent Global Navigation Satellite Systems (GNSS) constellations; so does the European Union (EU). Accurate EOPs are essential for long-term orbital maintenance of GNSS constellations, leaving the EU GALILEO GNSS vulnerable and reliant on the three superpowers. Generation of accurate EOPs by Europe is not possible due to its much smaller land mass and thus smaller achievable baselines. Even though there are many radio telescopes spread across Europe, these are separated by relatively short distances. The proposed stations that will be used to investigate this independent EOP network for Europe are the WETTZELL radio telescope in Germany, two German owned radio telescopes, TIGOCONC in Concepción, Chile, and OHIGGINS in Antarctica, as well as the HartRAO radio telescope in South Africa.

  17. Optimizing the MAC Protocol in Localization Systems Based on IEEE 802.15.4 Networks

    PubMed Central

    Claver, Jose M.; Ezpeleta, Santiago

    2017-01-01

    Radio frequency signals are commonly used in the development of indoor localization systems. The infrastructure of these systems includes some beacons placed at known positions that exchange radio packets with users to be located. When the system is implemented using wireless sensor networks, the wireless transceivers integrated in the network motes are usually based on the IEEE 802.15.4 standard. But, the CSMA-CA, which is the basis for the medium access protocols in this category of communication systems, is not suitable when several users want to exchange bursts of radio packets with the same beacon to acquire the radio signal strength indicator (RSSI) values needed in the location process. Therefore, new protocols are necessary to avoid the packet collisions that appear when multiple users try to communicate with the same beacons. On the other hand, the RSSI sampling process should be carried out very quickly because some systems cannot tolerate a large delay in the location process. This is even more important when the RSSI sampling process includes measures with different signal power levels or frequency channels. The principal objective of this work is to speed up the RSSI sampling process in indoor localization systems. To achieve this objective, the main contribution is the proposal of a new MAC protocol that eliminates the medium access contention periods and decreases the number of packet collisions to accelerate the RSSI collection process. Moreover, the protocol increases the overall network throughput taking advantage of the frequency channel diversity. The presented results show the suitability of this protocol for reducing the RSSI gathering delay and increasing the network throughput in simulated and real environments. PMID:28684666

  18. Optimizing the MAC Protocol in Localization Systems Based on IEEE 802.15.4 Networks.

    PubMed

    Pérez-Solano, Juan J; Claver, Jose M; Ezpeleta, Santiago

    2017-07-06

    Radio frequency signals are commonly used in the development of indoor localization systems. The infrastructure of these systems includes some beacons placed at known positions that exchange radio packets with users to be located. When the system is implemented using wireless sensor networks, the wireless transceivers integrated in the network motes are usually based on the IEEE 802.15.4 standard. But, the CSMA-CA, which is the basis for the medium access protocols in this category of communication systems, is not suitable when several users want to exchange bursts of radio packets with the same beacon to acquire the radio signal strength indicator (RSSI) values needed in the location process. Therefore, new protocols are necessary to avoid the packet collisions that appear when multiple users try to communicate with the same beacons. On the other hand, the RSSI sampling process should be carried out very quickly because some systems cannot tolerate a large delay in the location process. This is even more important when the RSSI sampling process includes measures with different signal power levels or frequency channels. The principal objective of this work is to speed up the RSSI sampling process in indoor localization systems. To achieve this objective, the main contribution is the proposal of a new MAC protocol that eliminates the medium access contention periods and decreases the number of packet collisions to accelerate the RSSI collection process. Moreover, the protocol increases the overall network throughput taking advantage of the frequency channel diversity. The presented results show the suitability of this protocol for reducing the RSSI gathering delay and increasing the network throughput in simulated and real environments.

  19. Discovery of Action Patterns and User Correlations in Task-Oriented Processes for Goal-Driven Learning Recommendation

    ERIC Educational Resources Information Center

    Zhou, Xiaokang; Chen, Jian; Wu, Bo; Jin, Qun

    2014-01-01

    With the high development of social networks, collaborations in a socialized web-based learning environment has become increasing important, which means people can learn through interactions and collaborations in communities across social networks. In this study, in order to support the enhanced collaborative learning, two important factors, user…

  20. Structuring and Regulating Collaborative Learning in Higher Education with Wireless Networks and Mobile Tools

    ERIC Educational Resources Information Center

    Jarvela, Sanna; Naykki, Piia; Laru, Jari; Luokkanen, Tiina

    2007-01-01

    In our recent research we have explored possibilities to scaffold collaborative learning in higher education with wireless networks and mobile tools. The pedagogical ideas are grounded on concepts of collaborative learning, including the socially shared origin of cognition, as well as self-regulated learning theory. This paper presents our three…

  1. Dishing Up the Data: The Role of Australian Space Tracking and Radioastronomy Facilities in the Exploration of the Solar System

    NASA Astrophysics Data System (ADS)

    Dougherty, K.; Sarkissian, J.

    2002-01-01

    The recent Australian film, The Dish, highlighted the role played by the Parkes Radio Telescope in tracking and communicating with the Apollo 11 mission. However the events depicted in this film represent only a single snapshot of the role played by Australian radio astronomy and space tracking facilities in the exploration of the Solar System. In 1960, NASA established its first deep space tracking station outside the United States at Island Lagoon, near Woomera in South Australia. From 1961 until 1972, this station was an integral part of the Deep Space Network, responsible for tracking and communicating with NASA's interplanetary spacecraft. It was joined in 1965 by the Tidbinbilla tracking station, located near Canberra in eastern Australia, a major DSN facility that is still in operation today. Other NASA tracking facilities (for the STADAN and Manned Space Flight networks) were also established in Australia during the 1960s, making this country home to the largest number of NASA tracking facilities outside the United States. At the same time as the Island Lagoon station was being established in South Australia, one of the world's major radio telescope facilities was being established at Parkes, in western New South Wales. This 64-metre diameter dish, designed and operated by the Commonwealth Scientific and Industrial Research Organisation (CSIRO), was also well-suited for deep space tracking work: its design was, in fact, adapted by NASA for the 64-metre dishes of the Deep Space Network. From Mariner II in 1962 until today, the Parkes Radio Telescope has been contracted by NASA on many occasions to support interplanetary spacecraft, as well as the Apollo lunar missions. This paper will outline the role played by both the Parkes Radio Telescope and the NASA facilities based in Australia in the exploration of the Solar System between 1960 and 1976, when the Viking missions landed on Mars. It will outline the establishment and operation of the Deep Space Network in Australia and consider the joint US-Australian agreement under which it was managed. It will also discuss the relationship of the NASA stations to the Parkes Radio Telescope and the integration of Parkes into the NASA network to support specific space missions. The particular involvement of Australian facilities in significant space missions will be highlighted and assessed.

  2. Investigating Patterns of Interaction in Networked Learning and Computer-Supported Collaborative Learning: A Role for Social Network Analysis

    ERIC Educational Resources Information Center

    de Laat, Maarten; Lally, Vic; Lipponen, Lasse; Simons, Robert-Jan

    2007-01-01

    The focus of this study is to explore the advances that Social Network Analysis (SNA) can bring, in combination with other methods, when studying Networked Learning/Computer-Supported Collaborative Learning (NL/CSCL). We present a general overview of how SNA is applied in NL/CSCL research; we then go on to illustrate how this research method can…

  3. SDR/STRS Flight Experiment and the Role of SDR-Based Communication and Navigation Systems

    NASA Technical Reports Server (NTRS)

    Reinhart, Richard C.

    2008-01-01

    This presentation describes an open architecture SDR (software defined radio) infrastructure, suitable for space-based radios and operations, entitled Space Telecommunications Radio System (STRS). SDR technologies will endow space and planetary exploration systems with dramatically increased capability, reduced power consumption, and less mass than conventional systems, at costs reduced by vigorous competition, hardware commonality, dense integration, minimizing the impact of parts obsolescence, improved interoperability, and software re-use. To advance the SDR architecture technology and demonstrate its applicability in space, NASA is developing a space experiment of multiple SDRs each with various waveforms to communicate with NASA s TDRSS satellite and ground networks, and the GPS constellation. An experiments program will investigate S-band and Ka-band communications, navigation, and networking technologies and operations.

  4. The Healthy Aging Research Network: Modeling Collaboration for Community Impact.

    PubMed

    Belza, Basia; Altpeter, Mary; Smith, Matthew Lee; Ory, Marcia G

    2017-03-01

    As the first Centers for Disease Control and Prevention (CDC) Prevention Research Centers Program thematic network, the Healthy Aging Research Network was established to better understand the determinants of healthy aging within older adult populations, identify interventions that promote healthy aging, and assist in translating research into sustainable community-based programs throughout the nation. To achieve these goals requires concerted efforts of a collaborative network of academic, community, and public health organizational partnerships. For the 2001-2014 Prevention Research Center funding cycles, the Healthy Aging Research Network conducted prevention research and promoted the wide use of practices known to foster optimal health. Organized around components necessary for successful collaborations (i.e., governance and infrastructure, shaping focus, community involvement, and evaluation and improvement), this commentary highlights exemplars that demonstrate the Healthy Aging Research Network's unique contributions to the field. The Healthy Aging Research Network's collaboration provided a means to collectively build capacity for practice and policy, reduce fragmentation and duplication in health promotion and aging research efforts, maximize the efficient use of existing resources and generate additional resources, and ultimately, create synergies for advancing the healthy aging agenda. This collaborative model was built upon a backbone organization (coordinating center); setting of common agendas and mutually reinforcing activities; and continuous communications. Given its successes, the Healthy Aging Research Network model could be used to create new and evaluate existing thematic networks to guide the translation of research into policy and practice. Copyright © 2016 American Journal of Preventive Medicine. Published by Elsevier Inc. All rights reserved.

  5. A Sensible Approach to Wireless Networking.

    ERIC Educational Resources Information Center

    Ahmed, S. Faruq

    2002-01-01

    Discusses radio frequency (R.F.) wireless technology, including industry standards, range (coverage) and throughput (data rate), wireless compared to wired networks, and considerations before embarking on a large-scale wireless project. (EV)

  6. Skill complementarity enhances heterophily in collaboration networks

    PubMed Central

    Xie, Wen-Jie; Li, Ming-Xia; Jiang, Zhi-Qiang; Tan, Qun-Zhao; Podobnik, Boris; Zhou, Wei-Xing; Stanley, H. Eugene

    2016-01-01

    Much empirical evidence shows that individuals usually exhibit significant homophily in social networks. We demonstrate, however, skill complementarity enhances heterophily in the formation of collaboration networks, where people prefer to forge social ties with people who have professions different from their own. We construct a model to quantify the heterophily by assuming that individuals choose collaborators to maximize utility. Using a huge database of online societies, we find evidence of heterophily in collaboration networks. The results of model calibration confirm the presence of heterophily. Both empirical analysis and model calibration show that the heterophilous feature is persistent along the evolution of online societies. Furthermore, the degree of skill complementarity is positively correlated with their production output. Our work sheds new light on the scientific research utility of virtual worlds for studying human behaviors in complex socioeconomic systems. PMID:26743687

  7. Impact of the Cancer Prevention and Control Research Network

    PubMed Central

    Ribisl, Kurt M.; Fernandez, Maria E.; Friedman, Daniela B.; Hannon, Peggy; Leeman, Jennifer; Moore, Alexis; Olson, Lindsay; Ory, Marcia; Risendal, Betsy; Sheble, Laura; Taylor, Vicky; Williams, Rebecca; Weiner, Bryan J.

    2018-01-01

    The Cancer Prevention and Control Research Network (CPCRN) is a thematic network dedicated to accelerating the adoption of evidence-based cancer prevention and control practices in communities by advancing dissemination and implementation science. Funded by the Centers for Disease Control and Prevention and National Cancer Institute, CPCRN has operated at two levels: Each participating Network Center conducts research projects with primarily local partners as well as multicenter collaborative research projects with state and national partners. Through multicenter collaboration, thematic networks leverage the expertise, resources, and partnerships of participating centers to conduct research projects collectively that might not be feasible individually. Although multicenter collaboration often is advocated, it is challenging to promote and assess. Using bibliometric network analysis and other graphical methods, this paper describes CPCRN’s multicenter publication progression from 2004 to 2014. Searching PubMed, Scopus, and Web of Science in 2014 identified 249 peer-reviewed CPCRN publications involving two or more centers out of 6,534 total. The research and public health impact of these multicenter collaborative projects initiated by CPCRN during that 10-year period were then examined. CPCRN established numerous workgroups around topics such as: 2-1-1, training and technical assistance, colorectal cancer control, federally qualified health centers, cancer survivorship, and human papillomavirus. The paper discusses the challenges that arise in promoting multicenter collaboration and the strategies that CPCRN uses to address those challenges. The lessons learned should broadly interest those seeking to promote multisite collaboration to address public health problems, such as cancer prevention and control. PMID:28215371

  8. Adaptive Traffic Route Control in QoS Provisioning for Cognitive Radio Technology with Heterogeneous Wireless Systems

    NASA Astrophysics Data System (ADS)

    Yamamoto, Toshiaki; Ueda, Tetsuro; Obana, Sadao

    As one of the dynamic spectrum access technologies, “cognitive radio technology,” which aims to improve the spectrum efficiency, has been studied. In cognitive radio networks, each node recognizes radio conditions, and according to them, optimizes its wireless communication routes. Cognitive radio systems integrate the heterogeneous wireless systems not only by switching over them but also aggregating and utilizing them simultaneously. The adaptive control of switchover use and concurrent use of various wireless systems will offer a stable and flexible wireless communication. In this paper, we propose the adaptive traffic route control scheme that provides high quality of service (QoS) for cognitive radio technology, and examine the performance of the proposed scheme through the field trials and computer simulations. The results of field trials show that the adaptive route control according to the radio conditions improves the user IP throughput by more than 20% and reduce the one-way delay to less than 1/6 with the concurrent use of IEEE802.16 and IEEE802.11 wireless media. Moreover, the simulation results assuming hundreds of mobile terminals reveal that the number of users receiving the required QoS of voice over IP (VoIP) service and the total network throughput of FTP users increase by more than twice at the same time with the proposed algorithm. The proposed adaptive traffic route control scheme can enhance the performances of the cognitive radio technologies by providing the appropriate communication routes for various applications to satisfy their required QoS.

  9. Visualization analysis of author collaborations in schizophrenia research.

    PubMed

    Wu, Ying; Duan, Zhiguang

    2015-02-19

    Schizophrenia is a serious mental illness that levies a heavy medical toll and cost burden throughout the world. Scientific collaborations are necessary for progress in psychiatric research. However, there have been few publications on scientific collaborations in schizophrenia. The aim of this study was to investigate the extent of author collaborations in schizophrenia research. This study used 58,107 records on schizophrenia from 2003 to 2012 which were downloaded from Science Citation Index Expanded (SCI Expanded) via Web of Science. CiteSpace III, an information visualization and analysis software, was used to make a visual analysis. Collaborative author networks within the field of schizophrenia were determined using published documents. We found that external author collaboration networks were more scattered while potential author collaboration networks were more compact. Results from hierarchical clustering analysis showed that the main collaborative field was genetic research in schizophrenia. Based on the results, authors belonging to different institutions and in different countries should be encouraged to collaborate in schizophrenia research. This will help researchers focus their studies on key issues, and allow each other to offer reasonable suggestions for making polices and providing scientific evidence to effectively diagnose, prevent, and cure schizophrenia.

  10. Methodology For The System Integration Of Adaptive Resilience In Armor

    DTIC Science & Technology

    2016-09-01

    military FM radio . Military FM radios operate in a set mode of frequencies . In today’s modern era, many other pathways of digital and analogue... communication exist, whether cellular network, satellite, or even the aging telephone lines. The common FM radio uses line-of-sight electromagnetic...Jackson 2009). Apollo 13 was to be the third intentional U.S.-manned lunar landing. The craft was launched on April 11 , 1970, from the Kennedy Space

  11. Report to the President: Realizing the Full Potential of Government-Held Spectrum to Spur Economic Growth

    DTIC Science & Technology

    2012-07-01

    managing the use of the Radio Frequency (RF) spectrum to ensure reliable emergency, civil, and government communications . At that time, when the rules of...or equipment and/or radio frequencies to provide electronic communication services under standard conditions (a class license) or authorizing the...Cognitive Radio Networks.” IEEE Communications Magazine (2008). Circular A- 11 : Preparation, Submission, and Execution of the Budget. Executive Office

  12. The Telecommunications and Data Acquisition Report

    NASA Technical Reports Server (NTRS)

    Posner, E. C. (Editor)

    1993-01-01

    This quarterly publication provides archival reports on developments in programs managed by JPL's Office of Telecommunications and Data Acquisition (TDA). In space communications, radio navigation, radio science, and ground-based radio and radar astronomy, it reports on activities of the Deep Space Network (DSN) in planning, supporting research and technology, implementation, and operations. Also included are standards activity at JPL for space data and information systems and reimbursable DSN work performed for other space agencies through NASA.

  13. The Telecommunications and Data Acquisition Report

    NASA Technical Reports Server (NTRS)

    Posner, E. C. (Editor)

    1991-01-01

    This quarterly reports on space communications, radio navigation, radio science, and ground based radio and radar astronomy in connection with the Deep Space Network (DSN) in planning, supporting research and technology, implementation, and in operations. Also included is standards activity at JPL for space data and information systems and DSN work. Specific areas of research are: Tracking and ground based navigation; Spacecraft and ground communications; Station control and system technology; DSN Systems Implementation; and DSN Operations.

  14. Leading Innovation and Change: Knowledge Creation by Schools for Schools

    ERIC Educational Resources Information Center

    Harris, Alma

    2008-01-01

    This article explores the process and practice of knowledge creation within development and research (D and R) networks. It focuses upon D and R networks in England that are currently engaged in collaboration and innovation. Early evaluative evidence suggests that D and R school networks offer "spaces" for collaborative working, mutual…

  15. Implementation of a Framework for Collaborative Social Networks in E-Learning

    ERIC Educational Resources Information Center

    Maglajlic, Seid

    2016-01-01

    This paper describes the implementation of a framework for the construction and utilization of social networks in ELearning. These social networks aim to enhance collaboration between all E-Learning participants (i.e. both traineeto-trainee and trainee-to-tutor communication are targeted). E-Learning systems that include a so-called "social…

  16. Filling the gap between disaster preparedness and response networks of urban emergency management: Following the 2013 Seoul Floods.

    PubMed

    Song, Minsun; Jung, Kyujin

    2015-01-01

    To examine the gap between disaster preparedness and response networks following the 2013 Seoul Floods in which the rapid transmission of disaster information and resources was impeded by severe changes of interorganizational collaboration networks. This research uses the 2013 Seoul Emergency Management Survey data that were collected before and after the floods, and total 94 organizations involving in coping with the floods were analyzed in bootstrap independent-sample t-test and social network analysis through UCINET 6 and STATA 12. The findings show that despite the primary network form that is more hierarchical, horizontal collaboration has been relatively invigorated in actual response. Also, interorganizational collaboration networks for response operations seem to be more flexible grounded on improvisation to coping with unexpected victims and damages. Local organizations under urban emergency management are recommended to tightly build a strong commitment for joint response operations through full-size exercises at the metropolitan level before a catastrophic event. Also, interorganizational emergency management networks need to be restructured by reflecting the actual response networks to reduce collaboration risk during a disaster. This research presents a critical insight into inverse thinking of the view designing urban emergency management networks and provides original evidences for filling the gap between previously coordinated networks for disaster preparedness and practical response operations after a disaster.

  17. Los Angeles FOT spread spectrum radio traffic signal interconnect evaluation task : final report on full deployment

    DOT National Transportation Integrated Search

    1998-10-01

    The use of a spread spectrum radio network (SSRN) as an alternative to hard-wired communications between field equipment and the City of Los Angeless Automated Traffic Surveillance and Control (ATSAC) system has been investigated. The aim of using...

  18. Radio Frequency Based Programmable Logic Controller Anomaly Detection

    DTIC Science & Technology

    2013-09-01

    include wireless radios, IEEE 802.15 Blue- tooth devices, cellular phones, and IEEE 802.11 WiFi networking devices. While wireless communication...MacKenzie, H. Shamoon Malware and SCADA Security What are the Im- pacts? . Technical Report, Tofino Security, Sep 2012. 61. Mateti,P. Hacking Techniques

  19. DSN radio science system design and testing for Voyager-Neptune encounter

    NASA Technical Reports Server (NTRS)

    Ham, N. C.; Rebold, T. A.; Weese, J. F.

    1989-01-01

    The Deep Space Network (DSN) Radio Science System presently implemented within the Deep Space Network was designed to meet stringent requirements imposed by the demands of the Voyager-Neptune encounter and future missions. One of the initial parameters related to frequency stability is discussed. The requirement, specification, design, and methodology for measuring this parameter are described. A description of special instrumentation that was developed for the test measurements and initial test data resulting from the system tests performed at Canberra, Australia and Usuda, Japan are given.

  20. Methods for developing jam-resistant security communications networks at fixed-site facilities

    NASA Astrophysics Data System (ADS)

    Gangel, D. J.; Heustess, J. E.; Snell, M. K.

    Considerable work has been done identifying and developing equipment and procedures that can be used to improve the survivability of a security communications network during a jamming assault. Insight is given into alternate communications methods that can be used to develop resistance to jamming by supplementing existing radio communications. The spatial properties of jamming are then discussed and examples of how these properties can be explocited are examined. Also discussed are spread-spectrum radios that are highly resistant to jamming and the importance of jamming exercises.

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