Science.gov

Sample records for advanced mobile communications

  1. Advanced Communications Technology: Mobile Communications Requirements Report

    NASA Astrophysics Data System (ADS)

    1998-05-01

    The Coast Guard's mobile communications requirements will outstrip existing system capabilities, available capacity, and affordability by the late 1990s. This will require changes in the mix of mobile communications equipment and services used by operational units. New commercial mobile satellite services are available now, with many others arriving on the market between 1998 and 2003. These new services present unique opportunities to satisfy mission requirements, reduce investment in communications infrastructure, and realize more costeffective communications services. The Coast Guard Research and Development Center (R&DC) has undertaken an effort to identify and evaluate current and emerging satellite services that may be used to satisfy Coast Guard mobile communications requirements. As part of this effort, Anteon Corporation has been tasked by R&DC to collect the mobile communications functional requirements that have been identified by program managers. Anteon analysts have reviewed the Government Furnished Information (GFI) and researched other related documentation to identify and collect the requirements that may be used to describe the needed operating environment. Anteon analysts assessed the functional requirements to develop system requirements that describe the features that a communications system must provide to support the functional requirements. This report presents the current and projected Coast Guard mobile communications system requirements.

  2. Advanced communications payload for mobile applications

    NASA Technical Reports Server (NTRS)

    Ames, S. A.; Kwan, R. K.

    1990-01-01

    An advanced satellite payload is proposed for single hop linking of mobile terminals of all classes as well as Very Small Aperture Terminal's (VSAT's). It relies on an intensive use of communications on-board processing and beam hopping for efficient link design to maximize capacity and a large satellite antenna aperture and high satellite transmitter power to minimize the cost of the ground terminals. Intersatellite links are used to improve the link quality and for high capacity relay. Power budgets are presented for links between the satellite and mobile, VSAT, and hub terminals. Defeating the effects of shadowing and fading requires the use of differentially coherent demodulation, concatenated forward error correction coding, and interleaving, all on a single link basis.

  3. Antenna technology for advanced mobile communication systems

    NASA Technical Reports Server (NTRS)

    Rammos, Emmanuel; Roederer, Antoine; Rogard, Roger

    1988-01-01

    The onboard antenna front end is the key subsystem conditioning configuration and performance of mobile communication satellites. The objectives of this paper are to demonstrate this key role and to review L-band satellite antenna technology for earth coverage and regional applications. Multibeam arrays are first discussed, then unfurlable and inflatable reflector antennas are described. These technologies are now qualified in Europe for future mobile systems, for which the optimum choice of antenna technology has been found to be the key to efficient use of spectrum and power resources.

  4. A Communication Architecture for an Advanced Extravehicular Mobile Unit

    NASA Technical Reports Server (NTRS)

    Ivancic, William D.; Sands, Obed S.; Bakula, Casey J.; Oldham, Daniel R.; Wright, Ted; Bradish, Martin A.; Klebau, Joseph M.

    2014-01-01

    This document describes the communication architecture for the Power, Avionics and Software (PAS) 1.0 subsystem for the Advanced Extravehicular Mobility Unit (AEMU). The following systems are described in detail: Caution Warning and Control System, Informatics, Storage, Video, Audio, Communication, and Monitoring Test and Validation. This document also provides some background as well as the purpose and goals of the PAS subsystem being developed at Glenn Research Center (GRC).

  5. Advanced mobile satellite communications using COMETS satellite in MM-wave and Ka-band

    NASA Technical Reports Server (NTRS)

    Ohmori, Shingo; Isobe, Shunkichi; Takeuchi, Makoto; Naito, Hideyuki

    1993-01-01

    Early in the 21st century, the demand for personal communications using mobile, hand-held, and VSAT terminals will rapidly increase. In a future system, many different types of services should be provided with one-hop connection. The Communications Research Laboratory (CRL) has studied a future advanced mobile satellite communications system using millimeter wave and Ka band. In 1990, CRL started the Communications and Broadcasting Engineering Test Satellite (COMETS) project. The satellite has been developed in conjunction with NASDA and will be launched in 1997. This paper describes the COMETS payload configuration and the experimental system for the advanced mobile communications mission.

  6. Advanced mobile satellite communications experiment in MM-wave and Ka-band using Japans's COMETS

    NASA Astrophysics Data System (ADS)

    Isobe, Shunkichi; Hamamoto, Naokazu; Takeuchi, Makoto; Ohmori, Shingo; Yamamoto, Minoru

    Early in the 21st century, the demand for personal communications using mobile, hand-held and very small aperture terminals (VSAT) will rapidly increase. In a future system, many different types of services should be provided with one-hop connection. The Communications Research Laboratory (CRL) has studied a future advanced mobile satellite communications system using millimeter-wave and Ka-band. In 1990, CRL started the Communications and Broadcasting Engineering Test Satellite (COMETS) project. The satellite has been developed in conjunction with the National Space Development Agency of Japan (NASDA) and will be launched in 1997. This paper describes the COMETS payload configuration and the experimental system for the advanced mobile communications mission. The 2-m-diameter on-board antenna has three beams, two adjacent Ka-band beams and one millimeter-wave beam. The two Ka-band transponders have high output power SSPAs of 20 W and 10 W. The millimeter-wave transponder consists of a 20 W traveling wave tube amplifier (TWTA) and a high electron mobility transistor/low noise amplifier (HEMT/LNA) with a low noise figure of 3 dB.

  7. Advanced mobile satellite communications system using Ka and MM-wave bands in Japan's R and D satellite project

    NASA Technical Reports Server (NTRS)

    Isobe, Shunkichi; Ohmori, Shingo; Hamamoto, Naokazu; Yamamoto, Minoru

    1991-01-01

    Communications Research Laboratory (CRL) studied an advanced mobile satellite communications system using Ka and millimeter-wave bands in the R&D Satellite project. The project started in 1990 and the satellite will be launched in 1997. On-board multi-beam interconnecting is one of basic functions to realize one-hop connection among Very Small Aperture Terminals (VSATs), mobile, and hand-held terminals in future mobile satellite communications system. An Intermediate Frequency (IF) filter bank and regenerative transponder are suitable for this function. The transponder configuration of an advanced mobile communications mission of the R&D Satellite for experiment is shown. High power transmitters of Ka and millimeter-wave bands, a 3x3 IF filter band and Single Channel Per Carrier/Time Division Multiplexing (SCPC/TDM) regenerative MODEMS, which will be boarded on the R&D Satellite, are being developed for the purpose of studying the feasibility of advanced mobile communications system.

  8. A Mobile Communications Space Link Between the Space Shuttle Orbiter and the Advanced Communications Technology Satellite

    NASA Technical Reports Server (NTRS)

    Fink, Patrick; Arndt, G. D.; Bondyopadhyay, P.; Shaw, Roland

    1994-01-01

    A communications experiment is described as a link between the Space Shuttle Orbiter (SSO) and the Advanced Communications Technology Satellite (ACTS). Breadboarding for this experiment has led to two items with potential for commercial application: a 1-Watt Ka-band amplifier and a Ka-band, circularly polarized microstrip antenna. Results of the hybrid Ka-band amplifier show gain at 30 dB and a saturated output power of 28.5 dBm. A second version comprised of MMIC amplifiers is discussed. Test results of the microstrip antenna subarray show a gain of approximately 13 dB and excellent circular polarization.

  9. Proceedings of the Workshop on Advanced Network and Technology Concepts for Mobile, Micro, and Personal Communications

    NASA Technical Reports Server (NTRS)

    Paul, Lori (Editor)

    1991-01-01

    The Workshop on Advanced Network and Technology Concepts for Mobile, Micro, and Personal Communications was held at NASA's JPL Laboratory on 30-31 May 1991. It provided a forum for reviewing the development of advanced network and technology concepts for turn-of-the-century telecommunications. The workshop was organized into three main categories: (1) Satellite-Based Networks (L-band, C-band, Ku-band, and Ka-band); (2) Terrestrial-Based Networks (cellular, CT2, PCN, GSM, and other networks); and (3) Hybrid Satellite/Terrestrial Networks. The proceedings contain presentation papers from each of the above categories.

  10. Autonomous mobile communication relays

    NASA Astrophysics Data System (ADS)

    Nguyen, Hoa G.; Everett, Hobart R.; Manouk, Narek; Verma, Ambrish

    2002-07-01

    Maintaining a solid radio communication link between a mobile robot entering a building and an external base station is a well-recognized problem. Modern digital radios, while affording high bandwidth and Internet-protocol-based automatic routing capabilities, tend to operate on line-of-sight links. The communication link degrades quickly as a robot penetrates deeper into the interior of a building. This project investigates the use of mobile autonomous communication relay nodes to extend the effective range of a mobile robot exploring a complex interior environment. Each relay node is a small mobile slave robot equipped with sonar, ladar, and 802.11b radio repeater. For demonstration purposes, four Pioneer 2-DX robots are used as autonomous mobile relays, with SSC-San Diego's ROBART III acting as the lead robot. The relay robots follow the lead robot into a building and are automatically deployed at various locations to maintain a networked communication link back to the remote operator. With their on-board external sensors, they also act as rearguards to secure areas already explored by the lead robot. As the lead robot advances and RF shortcuts are detected, relay nodes that become unnecessary will be reclaimed and reused, all transparent to the operator. This project takes advantage of recent research results from several DARPA-funded tasks at various institutions in the areas of robotic simulation, ad hoc wireless networking, route planning, and navigation. This paper describes the progress of the first six months of the project.

  11. Experiment In Aeronautical-Mobile/Satellite Communication

    NASA Technical Reports Server (NTRS)

    Jedrey, Thomas C.; Lay, Norman E.; Dessouky, Khaled

    1992-01-01

    Report describes study of performance of digital mobile/satellite communication terminals of advanced design intended for use in ground stations and airplanes in aeronautical-mobile service. Study was collaboration of NASA, Federal Aviation Administration (FAA), Communications Satellite Corp. (COMSAT), and International Maritime Satellite System (INMARSAT).

  12. Effective Protocols for Mobile Communications and Networking

    SciTech Connect

    Espinoza, J.; Sholander, P.; Van Leeuwen, B,

    1998-12-01

    This report examines methods of mobile communications with an emphasis on mobile computing and wireless communications. Many of the advances in communications involve the use of Internet Protocol (IP), Asynchronous Transfer Mode (ATM), and ad hoc network protocols. However, many of the advances in these protocols have been focused on wired communications. Recently much focus has been directed at advancing communication technology in the area of mobile wireless networks. This report discusses various protocols used in mobile communications and proposes a number of extensions to existing protocols. A detailed discussion is also included on desirable protocol characteristics and evaluation criteria. In addition, the report includes a discussion on several network simulation tools that maybe used to evaluate network protocols.

  13. Land mobile communications satellite

    NASA Astrophysics Data System (ADS)

    Carnebianca, C.; Pavesi, B.; Tuozzi, A.

    1986-09-01

    The economic value and salient technical and operational characteristics of a European Land Mobile Communication Satellite (LMCS) to complement and supplement the demand for mobile services of Western European countries in the 1995 to 2005 time frames were assessed. A significant future expansion of demand for LCMS services on the part of the public is anticipated. Important augmentations of current service capabilities could be achieved by a satellite service, improving the overall system performances and/or assisting the PTT's in containing their investments in the required infrastructure. The satellite service itself could represent a profitable revenue producer.

  14. Fade-Free Mobile Communication

    NASA Technical Reports Server (NTRS)

    Stevenson, C. R.

    1986-01-01

    Scheme for mobile communication reduces multipath fading and interference between adjacent channels. Proposed communication system lends itself to almost completely digital implementation, eliminating costly and bulky crystal filters. Scheme suitable for satellite-aided or terrestrial mobile communication, including cellular mobile telephony, at frequencies in 150-to-900-MHz range.

  15. Terrestrial mobile communications

    NASA Astrophysics Data System (ADS)

    Rogard, R.; Steciw, A.

    1986-11-01

    Current and future mobile communications services in Europe are described, along with the technologies for meeting the market needs. A 450 MHz cellular system began operations in Scandinavian countries in 1981, and two 900 MHz systems entered service in the United Kingdom in 1985. Similar systems are being implemented in most European countries. Coding and access schemes are being studied for a pan-European 900 MHz system. Satellites can complement the system by providing service in coastal waters, regions of economic importance to Europe, and sparsely-populated areas. Improvements in vocodors, receiver gain, and technologies for the less-congested 14/11 or 30/20 GHz voice and data links are necessary. ESA studies with the Marecs satellite, preparatory to launch of a prototype mobile communication link, are summarized.

  16. Globalstar communications payload for global mobile communications

    NASA Astrophysics Data System (ADS)

    Louie, Ming; Monte, Paul; Tyner, Randy; Rouffet, Denis; Gilhousen, Klein S.

    1992-03-01

    The Globalstar LEO satellite-based mobile-communications system is evaluated with respect to its potential for global digital communications and for radio-determination satellite service. The significant novel attributes of the Globalsat payload are examined including code-division multiple-access technologies, beam-hopping and time-domain-duplexing (TDD) capabilities, and six elliptical spot-beam L/S-band antennas. The antennas are designed to address the 'near-far' problem associated with mobile systems through the use of the Isoflux design. The Isoflux beams provide gain contours that compensate for differences in the spacecraft/earth slant range and that provide low spillover illumination. Two candidate payloads are presented - one which incorporates TDD and beam hopping - and found to provide efficient global mobile-communications services for the Globalstar system. A single satellite can provide up to 2800 full-duplex voice channels, and TDD allows uplink and downlink signals to share the same frequency.

  17. Advanced extravehicular mobility unit study

    NASA Technical Reports Server (NTRS)

    Elkins, W.

    1982-01-01

    Components of the advanced extravehicular mobility unit (suit) are described. Design considerations for radiation protection, extravehicular operational pressure, mobility effects, tool/glove/effector, anthropometric definition, lighting, and equipment turnaround are addressed.

  18. Advanced communications satellite systems

    NASA Technical Reports Server (NTRS)

    Sivo, J. N.

    1983-01-01

    There is a rapidly growing demand for satellite circuits, particularly for domestic service within the U.S. NASA's current program is aimed at developing the high risk, advanced satellite communications technologies required to significantly increase the capacity of future satellite communications systems. Attention is given to aspects of traffic distribution and service scenario, problems related to effects of rain attenuation, details regarding system configuration, a 30/20 GHz technology development approach, an experimental flight system, the communications payload for the experimental flight system, a typical experiment flight system coverage, and a typical three axis stabilized flight spacecraft.

  19. Mobile antennas for COMETS advanced mobile Satcom experiment

    NASA Technical Reports Server (NTRS)

    Hase, Yoshihiro; Tanaka, Masato; Saito, Haruo

    1995-01-01

    Advanced mobile satellite communication experiments in the Ka-band and the mm-wave will be carried out using the COMETS satellite, which is scheduled for launch in 1997. Mobile antennas will play a much more key role in high frequency systems such as COMETS than in conventional L-band mobile systems. This paper describes three types of antennas which are now being developed by the Communications Research Laboratory (CRL) for the COMETS mobile experiments. One is a mechanically steered waveguide slot array antenna, another is an electronically steered active phased array antenna, and the third is a mechanically steered torus reflector antenna. The first two antennas will be used in the Ka-band, while the latter will be used in the mm-wave.

  20. Trends in mobile satellite communication

    NASA Technical Reports Server (NTRS)

    Johannsen, Klaus G.; Bowles, Mike W.; Milliken, Samuel; Cherrette, Alan R.; Busche, Gregory C.

    1993-01-01

    Ever since the U.S. Federal Communication Commission opened the discussion on spectrum usage for personal handheld communication, the community of satellite manufacturers has been searching for an economically viable and technically feasible satellite mobile communication system. Hughes Aircraft Company and others have joined in providing proposals for such systems, ranging from low to medium to geosynchronous orbits. These proposals make it clear that the trend in mobile satellite communication is toward more sophisticated satellites with a large number of spot beams and onboard processing, providing worldwide interconnectivity. Recent Hughes studies indicate that from a cost standpoint the geosynchronous satellite (GEOS) is most economical, followed by the medium earth orbit satellite (MEOS) and then by the low earth orbit satellite (LEOS). From a system performance standpoint, this evaluation may be in reverse order, depending on how the public will react to speech delay and collision. This paper discusses the trends and various mobile satellite constellations in satellite communication under investigation. It considers the effect of orbital altitude and modulation/multiple access on the link and spacecraft design.

  1. Advanced communications satellites

    NASA Technical Reports Server (NTRS)

    Sivo, J. N.

    1980-01-01

    The increase in demand for satellite communications services brought about shortages in available transponder capacity, especially at C-band. Interest shifted to the Ku-band frequency and currently carriers are rapidly moving to secure orbital slots for future satellite development. Projections of communications service demands over the next decade indiate growth in voice, data, and video services such that saturation of both C-band and Ku-band will occur by 1990. Emphasis must and will shift to Ka-band (20/30 GHz) frequency for fixed-satellite service. Advanced technologies such as multibeam antennas coupled with on-board satellite switching to allow implementation in this band of very high capacity satellite systems will be applied to meet the demand. Satellite system concepts that are likely in the 1990's and are likely to bring a new dimension to satellite delivered communication service are presented. The NASA 30/20 GHz communications satellite system demonstration program is discussed with emphasis on the related technology development.

  2. Advanced satellite communication system

    NASA Technical Reports Server (NTRS)

    Staples, Edward J.; Lie, Sen

    1992-01-01

    The objective of this research program was to develop an innovative advanced satellite receiver/demodulator utilizing surface acoustic wave (SAW) chirp transform processor and coherent BPSK demodulation. The algorithm of this SAW chirp Fourier transformer is of the Convolve - Multiply - Convolve (CMC) type, utilizing off-the-shelf reflective array compressor (RAC) chirp filters. This satellite receiver, if fully developed, was intended to be used as an on-board multichannel communications repeater. The Advanced Communications Receiver consists of four units: (1) CMC processor, (2) single sideband modulator, (3) demodulator, and (4) chirp waveform generator and individual channel processors. The input signal is composed of multiple user transmission frequencies operating independently from remotely located ground terminals. This signal is Fourier transformed by the CMC Processor into a unique time slot for each user frequency. The CMC processor is driven by a waveform generator through a single sideband (SSB) modulator. The output of the coherent demodulator is composed of positive and negative pulses, which are the envelopes of the chirp transform processor output. These pulses correspond to the data symbols. Following the demodulator, a logic circuit reconstructs the pulses into data, which are subsequently differentially decoded to form the transmitted data. The coherent demodulation and detection of BPSK signals derived from a CMC chirp transform processor were experimentally demonstrated and bit error rate (BER) testing was performed. To assess the feasibility of such advanced receiver, the results were compared with the theoretical analysis and plotted for an average BER as a function of signal-to-noise ratio. Another goal of this SBIR program was the development of a commercial product. The commercial product developed was an arbitrary waveform generator. The successful sales have begun with the delivery of the first arbitrary waveform generator.

  3. Telemedicine using mobile satellite communication.

    PubMed

    Murakami, H; Shimizu, K; Yamamoto, K; Mikami, T; Hoshimiya, N; Kondo, K

    1994-05-01

    With a view to providing paramedical care within moving vehicles, a telemedicine technique using mobile satellite communication was proposed. With this technique, the diagnosis from a specialist and the emergency care under his/her instructions would be available on the spot without unnecessary delay. The characteristic problems of this technique were identified as: channel capacity, size of the system, reliability of vital sign transmission, real-time operation and electromagnetic interference. Measures against these problems were devised, and their effectiveness was analyzed. A data format was designed and an experimental system was developed. The system can simultaneously transmit a color image, an audio signal, 3 channels ECG and blood pressures from a mobile station to a ground station. It can transmit an audio signal and error control signals from a ground station to a mobile station in a full duplex mode. Fundamental transmission characteristics were measured in a fixed station. Finally, experiments of medical data transmission were conducted with a navigating ship and an aircraft flying an international route. The measured threshold values of C/N(o) to guarantee satisfactory data reception were well below the lower boundary of C/N(o) of the communication link. Consequently, the feasibility of this technique was verified. PMID:8070809

  4. Advanced Mobility Handover for Mobile IPv6 Based Wireless Networks

    PubMed Central

    Safa Sadiq, Ali; Fisal, Norsheila Binti; Ghafoor, Kayhan Zrar; Lloret, Jaime

    2014-01-01

    We propose an Advanced Mobility Handover scheme (AMH) in this paper for seamless mobility in MIPv6-based wireless networks. In the proposed scheme, the mobile node utilizes a unique home IPv6 address developed to maintain communication with other corresponding nodes without a care-of-address during the roaming process. The IPv6 address for each MN during the first round of AMH process is uniquely identified by HA using the developed MN-ID field as a global permanent, which is identifying uniquely the IPv6 address of MN. Moreover, a temporary MN-ID is generated by access point each time an MN is associated with a particular AP and temporarily saved in a developed table inside the AP. When employing the AMH scheme, the handover process in the network layer is performed prior to its default time. That is, the mobility handover process in the network layer is tackled by a trigger developed AMH message to the next access point. Thus, a mobile node keeps communicating with the current access point while the network layer handover is executed by the next access point. The mathematical analyses and simulation results show that the proposed scheme performs better as compared with the existing approaches. PMID:25614890

  5. Advanced mobility handover for mobile IPv6 based wireless networks.

    PubMed

    Safa Sadiq, Ali; Fisal, Norsheila Binti; Ghafoor, Kayhan Zrar; Lloret, Jaime

    2014-01-01

    We propose an Advanced Mobility Handover scheme (AMH) in this paper for seamless mobility in MIPv6-based wireless networks. In the proposed scheme, the mobile node utilizes a unique home IPv6 address developed to maintain communication with other corresponding nodes without a care-of-address during the roaming process. The IPv6 address for each MN during the first round of AMH process is uniquely identified by HA using the developed MN-ID field as a global permanent, which is identifying uniquely the IPv6 address of MN. Moreover, a temporary MN-ID is generated by access point each time an MN is associated with a particular AP and temporarily saved in a developed table inside the AP. When employing the AMH scheme, the handover process in the network layer is performed prior to its default time. That is, the mobility handover process in the network layer is tackled by a trigger developed AMH message to the next access point. Thus, a mobile node keeps communicating with the current access point while the network layer handover is executed by the next access point. The mathematical analyses and simulation results show that the proposed scheme performs better as compared with the existing approaches. PMID:25614890

  6. Communications Systems for Mobile Robotics

    SciTech Connect

    Futterman, J A; Pao, H

    2003-12-08

    Performance Confirmation is the activity by which the Yucca Mountain Project confirms that the engineered and natural containment barriers of this national nuclear waste repository are performing as predicted, so that an eventual decision to close the repository can be made. This activity involves systems that must be inspected and, in some cases, serviced by mobile robots. This paper discusses systems for underground mobile robot communications, including requirements, environments, options, issues, and down-select criteria. We reviewed a variety of systems, including Slotted Waveguide, Powerline Carrier, Leaky Feeder, Photonic Bandgap Fiber, Free-Space Optics, Millimeter Waves, Terahertz Systems, and RF Systems (including IEEE 802.11 a,b, and g, and Ultra-Wideband radio).

  7. Antennas for mobile satellite communications

    NASA Technical Reports Server (NTRS)

    Huang, John

    1991-01-01

    A NASA sponsored program, called the Mobile Satellite (MSAT) system, has prompted the development of several innovative antennas at L-band frequencies. In the space segment of the MSAT system, an efficient, light weight, circularly polarized microstrip array that uses linearly polarized elements was developed as a multiple beam reflector feed system. In the ground segment, a low-cost, low-profile, and very efficient microstrip Yagi array was developed as a medium-gain mechanically steered vehicle antenna. Circularly shaped microstrip patches excited at higher-order modes were also developed as low-gain vehicle antennas. A more recent effort called for the development of a 20/30 GHz mobile terminal antenna for future-generation mobile satellite communications. To combat the high insertion loss encountered at 20/30 GHz, series-fed Monolithic Microwave Integrated Circuit (MMIC) microstrip array antennas are currently being developed. These MMIC arrays may lead to the development of several small but high-gain Ka-band antennas for the Personal Access Satellite Service planned for the 2000s.

  8. Spread spectrum mobile radio communications

    NASA Astrophysics Data System (ADS)

    Gupta, S. C.; Soliman, S. S.

    1987-02-01

    This report is made up of two parts. In the first part we present additional results on the performance of random access protocols for mobile packet radio networks. The effect of three different types of diversity reception in Nakagami fading environment on the channel throughput and the average packet delay of nonpersistent carrier sense multiple access (NPCSMA) protocol is considered. Expressions for the probability of packet error with diversity receptions are newly obtained for both independent and correlated diversity branches. A noncoherent frequency shift keying modulation scheme is assumed. In the second part a comprehensive study of the problem of synchronization over fading dispersive channels is presented. Synchronization is a fundamental problem in digital communications as used in mobile radio. In the first chapter, we consider a simple binary detection problem. The effect of receiver mismatch is investigated. A closed form expression for the probability of false alarm and probability of detection are given, also a set of curves are provided to demonstrate the amount of degradation for under-spread channels with some special scattering.

  9. SAW based systems for mobile communications satellites

    NASA Technical Reports Server (NTRS)

    Peach, R. C.; Miller, N.; Lee, M.

    1993-01-01

    Modern mobile communications satellites, such as INMARSAT 3, EMS, and ARTEMIS, use advanced onboard processing to make efficient use of the available L-band spectrum. In all of these cases, high performance surface acoustic wave (SAW) devices are used. SAW filters can provide high selectivity (100-200 kHz transition widths), combined with flat amplitude and linear phase characteristics; their simple construction and radiation hardness also makes them especially suitable for space applications. An overview of the architectures used in the above systems, describing the technologies employed, and the use of bandwidth switchable SAW filtering (BSSF) is given. The tradeoffs to be considered when specifying a SAW based system are analyzed, using both theoretical and experimental data. Empirical rules for estimating SAW filter performance are given. Achievable performance is illustrated using data from the INMARSAT 3 engineering model (EM) processors.

  10. Mobile Perspectives: On Websites. Mobile Matters--Communication Trumps Technology

    ERIC Educational Resources Information Center

    Evans, Susan T.

    2011-01-01

    Mobile technology is a favorite discussion topic among senior IT leaders and higher education administrators. Mobile is the future for content delivery. Colleges and universities need to establish a strategy now and make the decisions necessary to take advantage of this communication opportunity. In this article, the author recommends making…

  11. Reduced-Bandwidth Coding for Mobile Communication

    NASA Technical Reports Server (NTRS)

    Davarian, F.

    1986-01-01

    Fade-resistant mobile systems use power and spectrum efficiently. Transmission system employs tone-calibrated technique (TCT). Residual carrier used in technique to reduce fading-induced effects and coherently demodulate received signal. TCT potentially efficient in use of power and of frequency spectrum. Coding technique, intended for residual-carrier transmission system, alleviates fading and spectrum crowding that hamper mobile communications.

  12. Repeated Transmissions In Mobile/Satellite Communications

    NASA Technical Reports Server (NTRS)

    Yan, Tsun-Yee; Clare, Loren P.

    1988-01-01

    Repetition increases throughput and decreases delay. Paper discusses theoretical performance of communication system for land-mobile stations with satellite relay using ALOHA random-access protocol modified for repeated transimssions. Methods and conclusions contribute to general understanding of packet communications in fading channels.

  13. USDA Forest Service mobile satellite communications applications

    NASA Technical Reports Server (NTRS)

    Warren, John R.

    1990-01-01

    The airborne IR signal processing system being developed will require the use of mobile satellite communications to achieve its full capability and improvement in delivery timeliness of processed IR data to the Fire Staff. There are numerous other beneficial uses, both during wildland fire management operations or in daily routine tasks, which will also benefit from the availability of reliable communications from remote areas.

  14. Advanced Communications Technology Satellite (ACTS)

    NASA Astrophysics Data System (ADS)

    Gedney, Richard T.; Schertler, Ronald J.

    1989-06-01

    The NASA Advanced Communications Technology Satellite (ACTS) was conceived to help maintain U.S. leadership in the world's communications-satellite market. This experimental satellite is expected to be launched by NASA in 1992 and to furnish the technology necessary for establishing very small aperture terminal digital networks which provide on-demand full-mesh connectivity, and 1.544-MBPS services with only a single hop. Utilizing on-board switching and processing, each individual voice or data circuit can be separately routed to any location in the network. This paper provides an overview of the ACTS and discusses the value of the technology for future communications systems.

  15. Advanced Communications Technology Satellite (ACTS)

    NASA Technical Reports Server (NTRS)

    Gedney, Richard T.; Schertler, Ronald J.

    1989-01-01

    The NASA Advanced Communications Technology Satellite (ACTS) was conceived to help maintain U.S. leadership in the world's communications-satellite market. This experimental satellite is expected to be launched by NASA in 1992 and to furnish the technology necessary for establishing very small aperture terminal digital networks which provide on-demand full-mesh connectivity, and 1.544-MBPS services with only a single hop. Utilizing on-board switching and processing, each individual voice or data circuit can be separately routed to any location in the network. This paper provides an overview of the ACTS and discusses the value of the technology for future communications systems.

  16. Advances in public health communication.

    PubMed

    Maibach, E; Holtgrave, D R

    1995-01-01

    There have been tremendous advances in recent years in the innovative use of communication to address public health problems. This article outlines the use of communication techniques and technologies to (positively) influence individuals, populations, and organizations for the purpose of promoting conditions conducive to human and environmental health. The approaches described include social marketing, risk communication, and behavioral decision theory, entertainment education, media advocacy, and interactive decision support systems. We also address criticism of these approaches among public health professionals because of perceived discrepancies in their inherent goals and objectives. In conclusion, we call for the rapid diffusion of state-of-the-art public health communication practices into public health service agencies and organizations. PMID:7639871

  17. Mobile satellite communications in the Forest Service

    NASA Technical Reports Server (NTRS)

    Warren, John R.

    1988-01-01

    There are usually some places within a forest that do not have adequate communication coverage due to line-of-sight or other reasons. These areas are generally known by the foresters and radio technicians and allowances are made for that when working or traveling in those areas. However, when wildfire or other emergencies occur, communications are vital because wildfires can require hundreds of firefighters and cover thousands of acres. During these emergency operations, the existing communications are not adequate and complete radio systems are moved into the area for the conduct of fire communications. Incident command posts (ICPs) and fire camps are set up in remote locations and there is constant need for communications in the fire area and to agency headquarters and dispatch offices. Mobile satellite communications would be an ideal supplement to the Forest Service's current communications system in aiding forest fire control activities.

  18. Modeling and Analysis of Mobility Management in Mobile Communication Networks

    PubMed Central

    Yoon, Ji Hyun; Kim, Chesoong

    2014-01-01

    Many strategies have been proposed to reduce the mobility management cost in mobile communication networks. This paper studies the zone-based registration methods that have been adopted by most mobile communication networks. We focus on two special zone-based registration methods, called two-zone registration (2Z) and two-zone registration with implicit registration by outgoing calls (2Zi). We provide a new mathematical model to analyze the exact performance of 2Z and 2Zi. We also present various numerical results, to compare the performance of 2Zi with those of 2Z and one-zone registration (1Z), and show that 2Zi is superior to 2Z as well as 1Z in most cases. PMID:24883368

  19. Satellite multiple access systems for mobile communication

    NASA Technical Reports Server (NTRS)

    Lewis, J. L.

    1979-01-01

    This paper considers multiple access techniques for a mobile radio system which incorporates a geosynchronous orbiting satellite repeater through which mobile terminals communicate. The communication capacities of FDMA, TDMA and CDMA systems are examined for a 4 MHz bandwidth system to serve up to 10,000 users. An FDMA system with multibeam coverage is analyzed in detail. The system includes an order-wire network for demand-access control and reassignment of satellite channels. Satellite and terminal configurations are developed to a block diagram level and system costs and implementation requirements are discussed.

  20. Microstrip monopulse antenna for land mobile communications

    NASA Technical Reports Server (NTRS)

    Garcia, Q.; Martin, C.; Delvalle, J. C.; Jongejans, A.; Rinous, P.; Travers, M. N.

    1993-01-01

    Low cost is one of the main requirements in a communication system suitable for mass production, as it is the case for satellite land mobile communications. Microstrip technology fulfills this requirement which must be supported by a low cost tracking system design. The tradeoff led us to a prototype antenna composed of microstrip patches based on electromechanical closed-loop principle; the design and the results obtained are described.

  1. Time reversal communication with a mobile source.

    PubMed

    Song, H C

    2013-10-01

    Broadband underwater acoustic communication signals undergo either a compression or dilation in the presence of relative motion between a source and a receiver. Consequently, underwater acoustic communications with a mobile source/receiver require Doppler compensation through resampling. However, resampling may not be necessary when a channel-estimate-based time reversal approach is applied with frequent channel updates. Using experimental data (20-30 kHz), it is demonstrated that the performance of time reversal communication without resampling is similar to the case with resampling, along with the benefit of a modest computational saving. PMID:24116398

  2. Mobile satellite communications - Vehicle antenna technology update

    NASA Technical Reports Server (NTRS)

    Bell, D.; Naderi, F. M.

    1986-01-01

    This paper discusses options for vehicle antennas to be used in mobile satellite communications systems. Two types of antennas are identified. A non-steerable, azimuthally omnidirectional antenna with a modest gain of 3 to 5 dBi is suggested when a low cost is desired. Alternatively, mechanically or electronically steerable antennas with a higher gain of 10 to 12 dBi are suggested to alleviate power and spectrum scarcity associated with mobile satellite communications. For steerable antennas, both open-loop and closed-loop pointing schemes are discussed. Monopulse and sequential lobing are proposed for the mechanically steered and electronically steered antennas, respectively. This paper suggests a hybrid open-loop/closed-loop pointing technique as the best performer in the mobile satellite environment.

  3. Multidimensional Human Dynamics in Mobile Phone Communications

    PubMed Central

    Quadri, Christian; Zignani, Matteo; Capra, Lorenzo; Gaito, Sabrina; Rossi, Gian Paolo

    2014-01-01

    In today's technology-assisted society, social interactions may be expressed through a variety of techno-communication channels, including online social networks, email and mobile phones (calls, text messages). Consequently, a clear grasp of human behavior through the diverse communication media is considered a key factor in understanding the formation of the today's information society. So far, all previous research on user communication behavior has focused on a sole communication activity. In this paper we move forward another step on this research path by performing a multidimensional study of human sociality as an expression of the use of mobile phones. The paper focuses on user temporal communication behavior in the interplay between the two complementary communication media, text messages and phone calls, that represent the bi-dimensional scenario of analysis. Our study provides a theoretical framework for analyzing multidimensional bursts as the most general burst category, that includes one-dimensional bursts as the simplest case, and offers empirical evidence of their nature by following the combined phone call/text message communication patterns of approximately one million people over three-month period. This quantitative approach enables the design of a generative model rooted in the three most significant features of the multidimensional burst - the number of dimensions, prevalence and interleaving degree - able to reproduce the main media usage attitude. The other findings of the paper include a novel multidimensional burst detection algorithm and an insight analysis of the human media selection process. PMID:25068479

  4. Multidimensional human dynamics in mobile phone communications.

    PubMed

    Quadri, Christian; Zignani, Matteo; Capra, Lorenzo; Gaito, Sabrina; Rossi, Gian Paolo

    2014-01-01

    In today's technology-assisted society, social interactions may be expressed through a variety of techno-communication channels, including online social networks, email and mobile phones (calls, text messages). Consequently, a clear grasp of human behavior through the diverse communication media is considered a key factor in understanding the formation of the today's information society. So far, all previous research on user communication behavior has focused on a sole communication activity. In this paper we move forward another step on this research path by performing a multidimensional study of human sociality as an expression of the use of mobile phones. The paper focuses on user temporal communication behavior in the interplay between the two complementary communication media, text messages and phone calls, that represent the bi-dimensional scenario of analysis. Our study provides a theoretical framework for analyzing multidimensional bursts as the most general burst category, that includes one-dimensional bursts as the simplest case, and offers empirical evidence of their nature by following the combined phone call/text message communication patterns of approximately one million people over three-month period. This quantitative approach enables the design of a generative model rooted in the three most significant features of the multidimensional burst - the number of dimensions, prevalence and interleaving degree - able to reproduce the main media usage attitude. The other findings of the paper include a novel multidimensional burst detection algorithm and an insight analysis of the human media selection process. PMID:25068479

  5. Advanced Communications Technology Satellite (ACTS)

    NASA Technical Reports Server (NTRS)

    Plecity, Mark S.; Nall, Mark E.

    1991-01-01

    The NASA Advanced Communications Technology Satellite (ACTS) provides high risk technologies having the potential to dramatically enhance the capabilities of the satellite communications industry. This experimental satellite, which will be launched by NASA in 1993, will furnish the technology necessary for providing a range of services. Utilizing the ACTS very-high-gain-hopping spot-beam antennas with on-board routing and processing, Very Small Aperture Terminal (VSAT) digital networks which provide on-demand, full-mesh-convectivity 1.544-MBPS services with only a single hop can be established. The high-gain spot-beam antenna at Ka-band permits wide area, flexible networks providing high data rate services between modest-size earth terminals.

  6. Application of Mobile Router to Military Communications

    NASA Technical Reports Server (NTRS)

    Stewart, David H.; Ivancic, William D.; Bell, Terry L.; Kachmar, Brian A.; Shell, Dan; Leung, Kent

    2002-01-01

    Cisco Systems and NASA Glenn Research Center under a NASA Space Act Agreement have been performing joint networking research to apply Internet technologies and protocols to space-based communications. During this time, Cisco Systems developed the mobile-router which NASA and Cisco jointly tested. The early field trials of this technology have been successfully completed. The mobile-router is software code that resides in a network router. A Mobile-Router allows entire networks to roam while maintaining connectivity to the Internet. This router code is pertinent to a myriad of applications for both the government and commercial sectors. This technology will be applied to the wireless battlefield. NASA and the Department of Defense will utilize this technology for near-planetary observation and sensing spacecraft. It is the enabling technology for communication via the Internet or Intranets to aircraft. Information such as weather, air traffic control, voice and video can be easily and inexpensively transmitted to the aircraft using Internet protocols. The mobile router can be incorporated into emergency vehicles particularly ambulances and life-flight aircraft to provide real-time connectivity back to the hospital and healthcare experts. Commercial applications include entertainment services, IP telephone, and Internet connectivity for cruise ships, commercial shipping, tour busses, aircraft, and eventually cars. This paper will briefly describe the mobile router operation. An upcoming wide area network field test with application to US Coast Guard communications will be described. The paper will also highlight military and government networks that will benefit from the deployment of mobile router and the associated applications.

  7. Communication cliques in mobile phone calling networks

    NASA Astrophysics Data System (ADS)

    Li, Ming-Xia; Xie, Wen-Jie; Jiang, Zhi-Qiang; Zhou, Wei-Xing

    2015-11-01

    People in modern societies form different social networks through numerous means of communication. These communication networks reflect different aspects of human's societal structure. The billing records of calls among mobile phone users enable us to construct a directed calling network (DCN) and its Bonferroni network (SVDCN) in which the preferential communications are statistically validated. Here we perform a comparative investigation of the cliques of the original DCN and its SVDCN constructed from the calling records of more than nine million individuals in Shanghai over a period of 110 days. We find that the statistical properties of the cliques of the two calling networks are qualitatively similar and the clique members in the DCN and the SVDCN exhibit idiosyncratic behaviors quantitatively. Members in large cliques are found to be spatially close to each other. Based on the clique degree profile of each mobile phone user, the most active users in the two calling networks can be classified in to several groups. The users in different groups are found to have different calling behaviors. Our study unveils interesting communication behaviors among mobile phone users that are densely connected to each other.

  8. NASA's mobile satellite communications program; ground and space segment technologies

    NASA Technical Reports Server (NTRS)

    Naderi, F.; Weber, W. J.; Knouse, G. H.

    1984-01-01

    This paper describes the Mobile Satellite Communications Program of the United States National Aeronautics and Space Administration (NASA). The program's objectives are to facilitate the deployment of the first generation commercial mobile satellite by the private sector, and to technologically enable future generations by developing advanced and high risk ground and space segment technologies. These technologies are aimed at mitigating severe shortages of spectrum, orbital slot, and spacecraft EIRP which are expected to plague the high capacity mobile satellite systems of the future. After a brief introduction of the concept of mobile satellite systems and their expected evolution, this paper outlines the critical ground and space segment technologies. Next, the Mobile Satellite Experiment (MSAT-X) is described. MSAT-X is the framework through which NASA will develop advanced ground segment technologies. An approach is outlined for the development of conformal vehicle antennas, spectrum and power-efficient speech codecs, and modulation techniques for use in the non-linear faded channels and efficient multiple access schemes. Finally, the paper concludes with a description of the current and planned NASA activities aimed at developing complex large multibeam spacecraft antennas needed for future generation mobile satellite systems.

  9. Pilot-Tone System for Mobile Communications

    NASA Technical Reports Server (NTRS)

    Davarian, F.

    1986-01-01

    In mobile communication system called tone-calibrated technique, pilot tone provides phase- and amplitude-calibration reference to enable coherent demodulation of signal at receiver despite fading. Signal received by or from mobile terminal faded due to motion of terminal and propagation of signal along multiple paths. Fading introduces random amplitude modulation and phase modulation with bandwidth of twice Doppler frequency shift. Degrading effects of multipath fading reduced. Tonecalibrated technique for use with phase-modulated data or telephony systems using Manchester digital pulse-code modulation.

  10. Advanced Management Communication: An Elective Course in Corporate Communication.

    ERIC Educational Resources Information Center

    Argenti, Paul A.

    1986-01-01

    Proposes a college-level elective course in advanced management communication that would teach future managers how to communicate with shareholders, the media, financial analysts, and the labor force. (SRT)

  11. Advanced Networks in Motion Mobile Sensorweb

    NASA Technical Reports Server (NTRS)

    Ivancic, William D.; Stewart, David H.

    2011-01-01

    Advanced mobile networking technology applicable to mobile sensor platforms was developed, deployed and demonstrated. A two-tier sensorweb design was developed. The first tier utilized mobile network technology to provide mobility. The second tier, which sits above the first tier, utilizes 6LowPAN (Internet Protocol version 6 Low Power Wireless Personal Area Networks) sensors. The entire network was IPv6 enabled. Successful mobile sensorweb system field tests took place in late August and early September of 2009. The entire network utilized IPv6 and was monitored and controlled using a remote Web browser via IPv6 technology. This paper describes the mobile networking and 6LowPAN sensorweb design, implementation, deployment and testing as well as wireless systems and network monitoring software developed to support testing and validation.

  12. 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.

  13. Lens Antenna For Mobile/Satellite Communication

    NASA Technical Reports Server (NTRS)

    Bodnar, D. G.; Rainer, B. K.

    1988-01-01

    Flat, compact antenna made of stripline elements aimed at fixed elevation angle but steered electronically in azimuth. Design simplified by maintaining fixed elevation and relying on width of beam to cover desired elevation range. Need for phase shifter at each radiating element eliminated by arranging elements in circles and feeding through stripline disks called "R-KR lenses". Used in Mobile/Satellite Service, antenna mounted on top of vehicle on Earth and used to keep transmitted and received antenna beams aimed approximately toward communication satellite.

  14. Frequency addressable beams for land mobile communications

    NASA Technical Reports Server (NTRS)

    Thompson, J. D.; Dubellay, G. G.

    1988-01-01

    Satellites used for mobile communications need to serve large numbers of small, low cost terminals. The most important parameters affecting the capacity of such systems are the satellite equivalent isotropically radiated power (EIRP) and gain to noise temperature ratio (G/T) and available bandwidth. Satellites using frequency addressed beams provide high EIRP and G/T with high-gain antenna beams that also permit frequency reuse over the composite coverage area. Frequency addressing is easy to implement and compatible with low-cost terminals and offers higher capacity than alternative approaches.

  15. History of Antenna Technology for Mobile Communications in Korea

    NASA Astrophysics Data System (ADS)

    Min, Kyeong-Sik; Park, Chul-Keun; Kang, Suk-Youb

    In this paper, we discuss the development of wireless and mobile communications in Korea, current technological trends, and the future outlook on technological developments. Since the introduction of the telegraph and the telephone in September 1885, Korea's wired and wireless communications industry has consistently developed for over 100 years. Since 1984, upon the provision of the mobile telecommunications service, the industry has seen drastic qualitative and quantitative growth in terms of both technical and economic aspects, which played a crucial role in the rapid growth of the digital industry in Korea. After the era of the analog cellular service based on the Advanced Mobile Phone System (AMPS), a precursor to the modern mobile service, Korea became the world's first country to commercialize Code Division Multiple Access (CDMA) in 1996 and succeeded in commercializing CDMA 2000 lx (IMT 2000) in 2001. With further developments in the mobile communication technology, the technology for antennas also saw drastic advancements. As the mobile antennas moved from the second to the third generation, they grew from external models to very small internal models. At the same time, they evolved into highly functional and high performance multiple band and wide band antennas. Furthermore, Korea was the first country to commercialize and offer the Wireless Broadband Internet (WiBro) service in 2006. By leading the wireless communications standardization and exerting remarkable efforts in research and development, Korea is consolidating its status as an Information Technology (IT) leader in the global market. The antenna's inherent importance will be further emphasized in the near future as it satisfies the performance and structural needs of portable terminals necessary for realizing the projected establishment of the ubiquitous world. It is thought that antenna technologies will not be limited to simple concepts as previously experienced but will utilize various kinds

  16. A review of earth observation using mobile personal communication devices

    NASA Astrophysics Data System (ADS)

    Ferster, Colin J.; Coops, Nicholas C.

    2013-02-01

    Earth observation using mobile personal communication devices (MPCDs) is a recent advance with considerable promise for acquiring important and timely measurements. Globally, over 5 billion people have access to mobile phones, with an increasing proportion having access to smartphones with capabilities such as a camera, microphone, global positioning system (GPS), data storage, and networked data transfer. Scientists can view these devices as embedded sensors with the potential to take measurements of the Earth's surface and processes. To advance the state of Earth observation using MPCDs, scientists need to consider terms and concepts, from a broad range of disciplines including citizen science, image analysis, and computer vision. In this paper, as a result of our literature review, we identify a number of considerations for Earth observation using MPCDs such as methods of field collection, collecting measurements over broad areas, errors and biases, data processing, and accessibility of data. Developing effective frameworks for mobile data collection with public participation and strategies for minimizing bias, in combination with advancements in image processing techniques, will offer opportunities to collect Earth sensing data across a range of scales and perspectives, complimenting airborne and spaceborne remote sensing measurements.

  17. The Army's Use of the Advanced Communications Technology Satellite

    NASA Technical Reports Server (NTRS)

    Ilse, Kenneth

    1996-01-01

    Tactical operations require military commanders to be mobile and have a high level of independence in their actions. Communications capabilities providing intelligence and command orders in these tactical situations have been limited to simple voice communications or low-rate narrow bandwidth communications because of the need for immediate reliable connectivity. The Advanced Communications Technology Satellite (ACTS) has brought an improved communications tool to the tactical commander giving the ability to gain access to a global communications system using high data rates and wide bandwidths. The Army has successfully tested this new capability of bandwidth-on-demand and high data rates for commanders in real-world conditions during Operation UPHOLD DEMOCRACY in Haiti during the fall and winter of 1994. This paper examines ACTS use by field commanders and details the success of the ACTS system in support of a wide variety of field condition command functions.

  18. Consensus in networks of mobile communicating agents

    NASA Astrophysics Data System (ADS)

    Baronchelli, Andrea; Díaz-Guilera, Albert

    2012-01-01

    Populations of mobile and communicating agents describe a vast array of technological and natural systems, ranging from sensor networks to animal groups. Here, we investigate how a group-level agreement may emerge in the continuously evolving network defined by the local interactions of the moving individuals. We adopt a general scheme of motion in two dimensions and we let the individuals interact through the minimal naming game, a prototypical scheme to investigate social consensus. We distinguish different regimes of convergence determined by the emission range of the agents and by their mobility, and we identify the corresponding scaling behaviors of the consensus time. In the same way, we rationalize also the behavior of the maximum memory used during the convergence process, which determines the minimum cognitive/storage capacity needed by the individuals. Overall, we believe that the simple and general model presented in this paper can represent a helpful reference for a better understanding of the behavior of populations of mobile agents.

  19. Communication-Related Abilities and Upward Mobility: A Longitudinal Investigation.

    ERIC Educational Resources Information Center

    Sypher, Beverly Davenport; Zorn, Theodore E., Jr.

    1986-01-01

    Studies relationships among four measures of communication abilities, and between these abilities and job level and upward mobility in a selected insurance company. Concludes that communication abilities are important to the success of individuals in organizations. (MS)

  20. Advanced communications experiments for Spacelab

    NASA Technical Reports Server (NTRS)

    Ehrlich, E.

    1975-01-01

    The Spacelab design and mission capabilities appear to provide a practical vehicle for meeting communication experiment needs. Results of recent discussions and numerous contractual activities have conclusively corroborated the potential useful role that a manned laboratory in space can afford to the communications community. Some examples of the experiments that appear presently as strong candidates for early flights on the Spacelab missions of the 1980s are discussed. Particular attention is given to radio frequency interference, bandwidth compressive modulation, laser experimentation, and use of large deployable communications antenna. It can be expected that the Spacelab will reduce the time, risk, and cost for conducting some communications experiments and developing the related space technology.

  1. Land vehicle antennas for satellite mobile communications

    NASA Technical Reports Server (NTRS)

    Haddad, H. A.; Paschen, D.; Pieper, B. V.

    1985-01-01

    Antenna designs applicable to future satellite mobile vehicle communications are examined. Microstrip disk, quadrifilar helix, cylindrical microstrip, and inverted V and U crossed-dipole low gain antennas (3-5 dBic) that provide omnidirectional coverage are described. Diagrams of medium gain antenna (9-12 dBic) concepts are presented; the antennas are classified into three types: (1) electronically steered with digital phase shifters; (2) electronically switched with switchable power divider/combiner; and (3) mechanically steered with motor. The operating characteristics of a conformal antenna with electronic beam steering and a nonconformal design with mechanical steering are evaluated with respect to isolation levels in a multiple satellite system. Vehicle antenna pointing systems and antenna system costs are investigated.

  2. Advanced Extravehicular Mobility Unit Informatics Software Design

    NASA Technical Reports Server (NTRS)

    Wright, Theodore

    2014-01-01

    This is a description of the software design for the 2013 edition of the Advanced Extravehicular Mobility Unit (AEMU) Informatics computer assembly. The Informatics system is an optional part of the space suit assembly. It adds a graphical interface for displaying suit status, timelines, procedures, and caution and warning information. In the future it will display maps with GPS position data, and video and still images captured by the astronaut.

  3. NASA's Advanced Communications Technology Satellite (ACTS)

    NASA Technical Reports Server (NTRS)

    Gedney, R. T.

    1983-01-01

    NASA recently restructured its Space Communications Program to emphasize the development of high risk communication technology useable in multiple frequency bands and to support a wide range of future communication needs. As part of this restructuring, the Advanced Communications Technology Satellite (ACTS) Project will develop and experimentally verify the technology associated with multiple fixed and scanning beam systems which will enable growth in communication satellite capacities and more effective utilization of the radio frequency spectrum. The ACTS requirements and operations as well as the technology significance for future systems are described.

  4. Advanced mobile networking, sensing, and controls.

    SciTech Connect

    Feddema, John Todd; Kilman, Dominique Marie; Byrne, Raymond Harry; Young, Joseph G.; Lewis, Christopher L.; Van Leeuwen, Brian P.; Robinett, Rush D. III; Harrington, John J.

    2005-03-01

    This report describes an integrated approach for designing communication, sensing, and control systems for mobile distributed systems. Graph theoretic methods are used to analyze the input/output reachability and structural controllability and observability of a decentralized system. Embedded in each network node, this analysis will automatically reconfigure an ad hoc communication network for the sensing and control task at hand. The graph analysis can also be used to create the optimal communication flow control based upon the spatial distribution of the network nodes. Edge coloring algorithms tell us that the minimum number of time slots in a planar network is equal to either the maximum number of adjacent nodes (or degree) of the undirected graph plus some small number. Therefore, the more spread out that the nodes are, the fewer number of time slots are needed for communication, and the smaller the latency between nodes. In a coupled system, this results in a more responsive sensor network and control system. Network protocols are developed to propagate this information, and distributed algorithms are developed to automatically adjust the number of time slots available for communication. These protocols and algorithms must be extremely efficient and only updated as network nodes move. In addition, queuing theory is used to analyze the delay characteristics of Carrier Sense Multiple Access (CSMA) networks. This report documents the analysis, simulation, and implementation of these algorithms performed under this Laboratory Directed Research and Development (LDRD) effort.

  5. Nationwide mobile communication systems. Volume 2, chapter 5: Appendix A

    NASA Astrophysics Data System (ADS)

    Schworer, William Joseph, III

    1990-06-01

    Previous chapters discussed nationwide mobile communication system technologies and modeled user costs and benefits. This chapter provides a brief overview of mobile communication system economics, the projected U.S. market for nationwide mobile communications, and the potential revenues. The basic cost structure of satellite and meteor-burst systems are also modeled. A combination of all these factors will ultimately govern which systems will be commercially successful. Because of improvements in technology, communication system costs and user terminal costs (A) per unit of capacity tend to decline over time. However, inflation tends to drive the price of an identical product upward over time.

  6. Advanced Communications Technology Satellite (ACTS)

    NASA Technical Reports Server (NTRS)

    Schertler, Ronald J.; Gedney, Richard T.

    1992-01-01

    An overview of the NASA ACTS program is presented. The key technologies of ACTS include spot beams, on-board baseband processing and routing, wide bandwidth (900 MHz), and Ka-band transponders. The discussion covers system description, current status of the spacecraft development, ACTS earth stations, NGS traffic terminal, USAT, land and aeronautical mobiles, high data rate and propagation receive only terminals, and ACTS experiments program.

  7. 78 FR 38361 - Certain Portable Electronic Communications Devices, Including Mobile Phones and Components...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-06-26

    ... COMMISSION Certain Portable Electronic Communications Devices, Including Mobile Phones and Components Thereof... States after importation of certain portable electronic ] communications devices, including mobile phones... importation of certain portable electronic communications devices, including mobile phones and...

  8. A generalized transmultiplexer and its application to mobile satellite communications

    NASA Technical Reports Server (NTRS)

    Ichiyoshi, Osamu

    1990-01-01

    A generalization of digital transmultiplexer technology is presented. The proposed method can realize transmultiplexer (TMUX) and transdemultiplexer (TDUX) filter banks whose element filters have bandwidths greater than the channel spacing frequency. This feature is useful in many communications applications. As an example, a satellite switched (SS) Frequency Division Multiple Access (FDMA) system is proposed for spot beam satellite communications, particularly for mobile satellite communications.

  9. Cockpit weather graphics using mobile satellite communications

    NASA Technical Reports Server (NTRS)

    Seth, Shashi

    1993-01-01

    Many new companies are pushing state-of-the-art technology to bring a revolution in the cockpits of General Aviation (GA) aircraft. The vision, according to Dr. Bruce Holmes - the Assistant Director for Aeronautics at National Aeronautics and Space Administration's (NASA) Langley Research Center, is to provide such an advanced flight control system that the motor and cognitive skills you use to drive a car would be very similar to the ones you would use to fly an airplane. We at ViGYAN, Inc., are currently developing a system called the Pilot Weather Advisor (PWxA), which would be a part of such an advanced technology flight management system. The PWxA provides graphical depictions of weather information in the cockpit of aircraft in near real-time, through the use of broadcast satellite communications. The purpose of this system is to improve the safety and utility of GA aircraft operations. Considerable effort is being extended for research in the design of graphical weather systems, notably the works of Scanlon and Dash. The concept of providing pilots with graphical depictions of weather conditions, overlaid on geographical and navigational maps, is extremely powerful.

  10. FD/DAMA Scheme For Mobile/Satellite Communications

    NASA Technical Reports Server (NTRS)

    Yan, Tsun-Yee; Wang, Charles C.; Cheng, Unjeng; Rafferty, William; Dessouky, Khaled I.

    1992-01-01

    Integrated-Adaptive Mobile Access Protocol (I-AMAP) proposed to allocate communication channels to subscribers in first-generation MSAT-X mobile/satellite communication network. Based on concept of frequency-division/demand-assigned multiple access (FD/DAMA) where partition of available spectrum adapted to subscribers' demands for service. Requests processed, and competing requests resolved according to channel-access protocol, or free-access tree algorithm described in "Connection Protocol for Mobile/Satellite Communications" (NPO-17735). Assigned spectrum utilized efficiently.

  11. Advances in learning for intelligent mobile robots

    NASA Astrophysics Data System (ADS)

    Hall, Ernest L.; Ghaffari, Masoud; Liao, Xiaoqun S.; Alhaj Ali, Souma M.

    2004-10-01

    Intelligent mobile robots must often operate in an unstructured environment cluttered with obstacles and with many possible action paths to accomplish a variety of tasks. Such machines have many potential useful applications in medicine, defense, industry and even the home so that the design of such machines is a challenge with great potential rewards. Even though intelligent systems may have symbiotic closure that permits them to make a decision or take an action without external inputs, sensors such as vision permit sensing of the environment and permit precise adaptation to changes. Sensing and adaptation define a reactive system. However, in many applications some form of learning is also desirable or perhaps even required. A further level of intelligence called understanding may involve not only sensing, adaptation and learning but also creative, perceptual solutions involving models of not only the eyes and brain but also the mind. The purpose of this paper is to present a discussion of recent technical advances in learning for intelligent mobile robots with examples of adaptive, creative and perceptual learning. The significance of this work is in providing a greater understanding of the applications of learning to mobile robots that could lead to important beneficial applications.

  12. Development of Mobile Communications in Slovenia: Looking to the Future Global Information (Mobile/Internet) Society.

    ERIC Educational Resources Information Center

    Simonic, Tomaz; Mlinar, Tomi

    2000-01-01

    Discusses the planning and provision of mobile communications in Slovenia and suggests areas that will be developed in the future. Topics include the global mobile market; digital mobile networks; evolution from voice to multimedia services; wireless application protocol; the Internet; general packet radio service; and universal mobile…

  13. Space Mobile Network: A Near Earth Communications and Navigation Architecture

    NASA Technical Reports Server (NTRS)

    Israel, David J.; Heckler, Gregory W.; Menrad, Robert J.

    2016-01-01

    This paper shares key findings of NASA's Earth Regime Network Evolution Study (ERNESt) team resulting from its 18-month effort to define a wholly new architecture-level paradigm for the exploitation of space by civil space and commercial sector organizations. Since the launch of Sputnik in October 1957 spaceflight missions have remained highly scripted activities from launch through disposal. The utilization of computer technology has enabled dramatic increases in mission complexity; but, the underlying premise that the diverse actions necessary to meet mission goals requires minute-by-minute scripting, defined weeks in advance of execution, for the life of the mission has remained. This archetype was appropriate for a "new frontier" but now risks overtly constraining the potential market-based opportunities for the innovation considered necessary to efficiently address the complexities associated with meeting communications and navigation requirements projected to be characteristics of the next era of space exploration: a growing number of missions in simultaneous execution, increased variance of mission types and growth in location/orbital regime diversity. The resulting ERNESt architectural cornerstone - the Space Mobile Network (SMN) - was envisioned as critical to creating an environment essential to meeting these future challenges in political, programmatic, technological and budgetary terms. The SMN incorporates technologies such as: Disruption Tolerant Networking (DTN) and optical communications, as well as new operations concepts such as User Initiated Services (UIS) to provide user services analogous to today's terrestrial mobile network user. Results developed in collaboration with NASA's Space Communications and Navigation (SCaN) Division and field centers are reported on. Findings have been validated via briefings to external focus groups and initial ground-based demonstrations. The SMN opens new niches for exploitation by the marketplace of mission

  14. Robust Timing Synchronization in Aeronautical Mobile Communication Systems

    NASA Technical Reports Server (NTRS)

    Xiong, Fu-Qin; Pinchak, Stanley

    2004-01-01

    the rankings of the Gardner Zero-Crossing Detector and both versions of the Early-Late Gate Synchronizer. The least robust models are the high and low-sample-rate Sliding Window Synchronizers. Consequently, the recommended replacement synchronizer for NASA's Advanced Air Transportation Technologies mobile aeronautical communications system is the high-sample-rate Modified Sliding Window Synchronizer. By incorporating this synchronizer into their system, NASA can be assured that their system will be operational in extremely adverse conditions. The quick convergence time of the MSWS should allow the use of high-level protocols. However, if NASA feels that reduced system complexity is the most important aspect of their replacement synchronizer, the Gardner Zero-Crossing Detector would be the best choice.

  15. Recent advances on integrated quantum communications

    NASA Astrophysics Data System (ADS)

    Orieux, Adeline; Diamanti, Eleni

    2016-08-01

    In recent years, the use of integrated technologies for applications in the field of quantum information processing and communications has made great progress. The resulting devices feature valuable characteristics such as scalability, reproducibility, low cost and interconnectivity, and have the potential to revolutionize our computation and communication practices in the future, much in the way that electronic integrated circuits have drastically transformed our information processing capacities since the last century. Among the multiple applications of integrated quantum technologies, this review will focus on typical components of quantum communication systems and on overall integrated system operation characteristics. We are interested in particular in the use of photonic integration platforms for developing devices necessary in quantum communications, including sources, detectors and both passive and active optical elements. We also illustrate the challenges associated with performing quantum communications on chip, by using the case study of quantum key distribution—the most advanced application of quantum information science. We conclude with promising perspectives in this field.

  16. Mobile Router Testing with Diverse RF Communications Links

    NASA Technical Reports Server (NTRS)

    Brooks, David; Hoder, Doug; Wilkins, Ryan

    2004-01-01

    This is a short report on demonstrations using Mobile IP and several diverse physical communications links to connect a mobile network to a fixed IPv4 internet. The first section is a description of the equipment used, followed by descriptions of the tests, the theoretical results, and finally conclusions and the actual data.

  17. Mobile e-Learning for Next Generation Communication Environment

    ERIC Educational Resources Information Center

    Wu, Tin-Yu; Chao, Han-Chieh

    2008-01-01

    This article develops an environment for mobile e-learning that includes an interactive course, virtual online labs, an interactive online test, and lab-exercise training platform on the fourth generation mobile communication system. The Next Generation Learning Environment (NeGL) promotes the term "knowledge economy." Inter-networking…

  18. The NASA Advanced Communications Technology Satellite (ACTS)

    NASA Astrophysics Data System (ADS)

    Beck, G. A.

    1984-10-01

    Forecasts indicate that a saturation of the capacity of the satellite communications service will occur in the U.S. domestic market by the early 1990s. In order to prevent this from happening, advanced technologies must be developed. NASA has been concerned with such a development. One key is the exploitation of the Ka-band (30/20 GHz), which is much wider than C- and Ku-bands together. Another is the use of multiple narrow antenna beams in the satellite to achieve large frequency reuse factors with very high antenna gains. NASA has developed proof-of-concept hardware components which form the basis for a flight demonstration. The Advanced Communications Technology Satellite (ACTS) system will provide this demonstration. Attention is given to the ACTS Program definition, the ACTS Flight System, the Multibeam Communications Package, and the spacecraft bus.

  19. Inferring human mobility using communication patterns

    NASA Astrophysics Data System (ADS)

    Palchykov, Vasyl; Mitrović, Marija; Jo, Hang-Hyun; Saramäki, Jari; Pan, Raj Kumar

    2014-08-01

    Understanding the patterns of mobility of individuals is crucial for a number of reasons, from city planning to disaster management. There are two common ways of quantifying the amount of travel between locations: by direct observations that often involve privacy issues, e.g., tracking mobile phone locations, or by estimations from models. Typically, such models build on accurate knowledge of the population size at each location. However, when this information is not readily available, their applicability is rather limited. As mobile phones are ubiquitous, our aim is to investigate if mobility patterns can be inferred from aggregated mobile phone call data alone. Using data released by Orange for Ivory Coast, we show that human mobility is well predicted by a simple model based on the frequency of mobile phone calls between two locations and their geographical distance. We argue that the strength of the model comes from directly incorporating the social dimension of mobility. Furthermore, as only aggregated call data is required, the model helps to avoid potential privacy problems.

  20. GSM-PKI solution enabling secure mobile communications.

    PubMed

    Jelekäinen, Pekka

    2004-03-31

    Because of its wide distribution and ease of use, the mobile phone, as a reliable personal communications channel, offers an excellent basis for the provision of reliable electronic communications services. In Finland, ca. 75% of the citizens have a mobile phone and, at present and most likely also in the future, it is the most widely spread service channel allowing reliable electronic communications. Despite the restricted functions of the mobile phone, the citizens can use the phone also as a communications medium. In 2001, the Finns sent over 1 billion SMS messages. In Finland, TeliaSonera Finland Oyi and the Population Register Centre (PRC) have closed a co-operation agreement with the aim of creating a mobile phone service for the electronic identification of a person. The co-operation launched is a significant development project from the perspective of the citizens. As a result, the consumers will have a new alternative for reliable electronic communications and commerce in data networks in addition to the electronic identification card. In the future, it will be possible to use the services of both public administration and the private sector by means of a mobile phone more reliably than before, without a physical visit, e.g. to a health centre or to another provider of healthcare services. The possibility of identification and signature by a mobile phone allows an easier provision of versatile services irrespective of time and place, because, in addition to voice, text message, and WAP functions, the service can be utilised also in communications services through the Internet, in which case, the mobile phone acts like a card reader. From the perspective of reliable personal mobile communications, the healthcare sector is one of the most significant and challenging application areas. PMID:15066565

  1. Development of a mobile satellite communication unit

    NASA Technical Reports Server (NTRS)

    Suzuki, Ryutaro; Ikegami, Tetsushi; Hamamoto, Naokazu; Taguchi, Tetsu; Endo, Nobuhiro; Yamamoto, Osamu; Ichiyoshi, Osamu

    1988-01-01

    A compact 210(W) x 280(H) x 330(D) mm mobile terminal capable of transmitting voice and data through L-band mobile satellites is described. The Voice Codec can convert an analog voice to or from digital codes at rates of 9.6, 8 and 4.8 kb/s by an MPC algorithm. The terminal functions with a single 12 V power supplied vehicle battery. The equipment can operate at any L-band frequency allocated for mobile uses in a full duplex mode and will soon be put into a field test via Japans's ETS-V satellite.

  2. Design of Hybrid Mobile Communication Networks for Planetary Exploration

    NASA Technical Reports Server (NTRS)

    Alena, Richard L.; Ossenfort, John; Lee, Charles; Walker, Edward; Stone, Thom

    2004-01-01

    The Mobile Exploration System Project (MEX) at NASA Ames Research Center has been conducting studies into hybrid communication networks for future planetary missions. These networks consist of space-based communication assets connected to ground-based Internets and planetary surface-based mobile wireless networks. These hybrid mobile networks have been deployed in rugged field locations in the American desert and the Canadian arctic for support of science and simulation activities on at least six occasions. This work has been conducted over the past five years resulting in evolving architectural complexity, improved component characteristics and better analysis and test methods. A rich set of data and techniques have resulted from the development and field testing of the communication network during field expeditions such as the Haughton Mars Project and NASA Mobile Agents Project.

  3. Land mobile communications satellite mission (LAMOCOSAMIS) Task 1: Market study

    NASA Astrophysics Data System (ADS)

    1985-12-01

    Land mobile communication service demand in Europe and the Mediterranean basin in the years 1995-2005 was estimated. A traffic model was derived. There is an exploding demand for land mobile communications in Europe, with overwhelming preference for two way telephone services. The users survey shows a surprising lack of sensitivity to prices and tariffs, which widely contributed to the preeminence of the needs for telephone services. This demand justifies that every effort be made to develop as fast as possible a compatible pan-European terrestrial mobile system. If a large proportion of the needs may be satisfied by terrestrial mobile system solutions, the potential remaining needs for telephony, outside of the presently planned terrestrial mobile, which can be served only by satellite, even under the pessimistic economic scenario and high cost/tariff assumptions, requires a number of equivalent telephone circuits which cannot be achieved with available state of the art technology.

  4. Signalling characteristics in satellite-aided land mobile communications

    NASA Technical Reports Server (NTRS)

    Anderson, R. E.

    1982-01-01

    The feasibility of land mobile radio communications has been demonstrated by a large number of experiments with NASA's ATS satellites. Significant differences in the propagation characteristics of satellite and terrestrial mobile signal paths were observed in the experiments. Terrestrial paths are best in cities where they can provide frequency reuse and assure communication by bouncing signals around obstructions. Satellites may be best in thinly populated areas because they eliminate the need for many tower mounted relays. The satellite paths do not have the severe Rayleigh fading that limits the range and signal quality of terrestrial paths if the satellite is above approximately ten degrees elevation, a value easily achieved for the United States. The experiments verified that high quality voice communications and other functions, such as data transmission and vehicle position surveillance, are easily accomplished through geostationary satellites with vehicle transmitter power and antenna gain no different than those of terrestrial mobile communications.

  5. Signalling characteristics in satellite-aided land mobile communications

    NASA Astrophysics Data System (ADS)

    Anderson, R. E.

    The feasibility of land mobile radio communications has been demonstrated by a large number of experiments with NASA's ATS satellites. Significant differences in the propagation characteristics of satellite and terrestrial mobile signal paths were observed in the experiments. Terrestrial paths are best in cities where they can provide frequency reuse and assure communication by bouncing signals around obstructions. Satellites may be best in thinly populated areas because they eliminate the need for many tower mounted relays. The satellite paths do not have the severe Rayleigh fading that limits the range and signal quality of terrestrial paths if the satellite is above approximately ten degrees elevation, a value easily achieved for the United States. The experiments verified that high quality voice communications and other functions, such as data transmission and vehicle position surveillance, are easily accomplished through geostationary satellites with vehicle transmitter power and antenna gain no different than those of terrestrial mobile communications.

  6. Increasing clinical presence of mobile communication technology: avoiding the pitfalls.

    PubMed

    Visvanathan, Akila; Gibb, Alan P; Brady, Richard R W

    2011-10-01

    Mobile communication technologies are employed in many diverse areas of healthcare delivery to provide improved quality and efficiency of communication and facilitate increased rapidity of data or information transfer. Mobile phones enable healthcare professionals to possess a portable platform from which to provide many healthcare-related applications and are a popular means to directly communicate with colleagues and patients. As involvement of mobile communication technology in healthcare delivery continues to rapidly expand, there are also important considerations of relevance to patient safety and security as a result. Here, we review the previous evidence of reported clinical risks associated with mobile communication technology, such as electromagnetic interference, confidentiality and data security, distraction/noise, infection control, and cross contamination. In conclusion, although mobile phones provide much putative potential improvement to healthcare delivery, further evaluation and research are required to both inform and protect health professionals and users of such technology in the healthcare environment and provide the evidence base to support the provision of clear and comprehensive guidelines. PMID:21780941

  7. Advanced Approach of Multiagent Based Buoy Communication

    PubMed Central

    Gricius, Gediminas; Drungilas, Darius; Andziulis, Arunas; Dzemydiene, Dale; Voznak, Miroslav; Kurmis, Mindaugas; Jakovlev, Sergej

    2015-01-01

    Usually, a hydrometeorological information system is faced with great data flows, but the data levels are often excessive, depending on the observed region of the water. The paper presents advanced buoy communication technologies based on multiagent interaction and data exchange between several monitoring system nodes. The proposed management of buoy communication is based on a clustering algorithm, which enables the performance of the hydrometeorological information system to be enhanced. The experiment is based on the design and analysis of the inexpensive but reliable Baltic Sea autonomous monitoring network (buoys), which would be able to continuously monitor and collect temperature, waviness, and other required data. The proposed approach of multiagent based buoy communication enables all the data from the costal-based station to be monitored with limited transition speed by setting different tasks for the agent-based buoy system according to the clustering information. PMID:26345197

  8. Advanced Approach of Multiagent Based Buoy Communication.

    PubMed

    Gricius, Gediminas; Drungilas, Darius; Andziulis, Arunas; Dzemydiene, Dale; Voznak, Miroslav; Kurmis, Mindaugas; Jakovlev, Sergej

    2015-01-01

    Usually, a hydrometeorological information system is faced with great data flows, but the data levels are often excessive, depending on the observed region of the water. The paper presents advanced buoy communication technologies based on multiagent interaction and data exchange between several monitoring system nodes. The proposed management of buoy communication is based on a clustering algorithm, which enables the performance of the hydrometeorological information system to be enhanced. The experiment is based on the design and analysis of the inexpensive but reliable Baltic Sea autonomous monitoring network (buoys), which would be able to continuously monitor and collect temperature, waviness, and other required data. The proposed approach of multiagent based buoy communication enables all the data from the costal-based station to be monitored with limited transition speed by setting different tasks for the agent-based buoy system according to the clustering information. PMID:26345197

  9. Antenna Design Considerations for the Advanced Extravehicular Mobility Unit

    NASA Technical Reports Server (NTRS)

    Bakula, Casey J.; Theofylaktos, Onoufrios

    2015-01-01

    NASA is designing an Advanced Extravehicular Mobility Unit (AEMU)to support future manned missions beyond low-Earth orbit (LEO). A key component of the AEMU is the communications assembly that allows for the wireless transfer of voice, video, and suit telemetry. The Extravehicular Mobility Unit (EMU) currently used on the International Space Station (ISS) contains a radio system with a single omni-directional resonant cavity antenna operating slightly above 400 MHz capable of transmitting and receiving data at a rate of about 125 kbps. Recent wireless communications architectures are calling for the inclusion of commercial wireless standards such as 802.11 that operate in higher frequency bands at much higher data rates. The current AEMU radio design supports a 400 MHz band for low-rate mission-critical data and a high-rate band based on commercial wireless local area network (WLAN) technology to support video, communication with non-extravehicular activity (EVA) assets such as wireless sensors and robotic assistants, and a redundant path for mission-critical EVA data. This paper recommends the replacement of the existing EMU antenna with a new antenna that maintains the performance characteristics of the current antenna but with lower weight and volume footprints. NASA has funded several firms to develop such an antenna over the past few years, and the most promising designs are variations on the basic patch antenna. This antenna technology at UHF is considered by the authors to be mature and ready for infusion into NASA AEMU technology development programs.

  10. Mobile Seamless Technology Enhanced CSL Oral Communication

    ERIC Educational Resources Information Center

    Lan, Yu-Ju; Lin, Yen-Ting

    2016-01-01

    The current study aimed at investigating how mobile seamless technology can be used to enhance the pragmatic competence of learners of Chinese as a second language (CSL). 34 overseas CSL learners participated in this study. They were randomly assigned into two groups: the classroom group, executing language tasks in fake contexts in a traditional…

  11. Advanced Communications Technology: Eighth District BOATRACS Test and Evaluation

    NASA Astrophysics Data System (ADS)

    1998-07-01

    One of the objectives of the Mobile Communications Infrastructure project is to conduct in-depth evaluations of mobile satellite systems that appear to meet Coast Guard communications requirements. The goal in testing these systems is to quantify how well they work and to provide some metrics to see how each of these systems could fit the needs of the Coast Guard. There are a variety of parameters that will be measured for each system. Most of the measurements are of the overall system, not the individual pieces. These parameters include coverage, availability, reliability, accuracy, interoperability, bandwidth, latency, ease of use, and cost. Some testing will be performed in the Advanced Communications Lab at the R&D Center, and some will be performed by placing systems on operational units for field testing. The Eight Coast Guard District has an extremely large AOR encompassing 26 States. The District is responsible for 1,200 miles of coastline and 10,300 miles of inland waterways. The major missions are Law Enforcement, Search and Rescue, and Pollution Response.

  12. Potential markets for a satellite-based mobile communications system

    NASA Technical Reports Server (NTRS)

    Jamieson, W. M.; Peet, C. S.; Bengston, R. J.

    1976-01-01

    The objective of the study was to define the market needs for improved land mobile communications systems. Within the context of this objective, the following goals were set: (1) characterize the present mobile communications industry; (2) determine the market for an improved system for mobile communications; and (3) define the system requirements as seen from the potential customer's viewpoint. The scope of the study was defined by the following parameters: (1) markets were confined to U.S. and Canada; (2) range of operation generally exceeded 20 miles, but this was not restrictive; (3) the classes of potential users considered included all private sector users, and non-military public sector users; (4) the time span examined was 1975 to 1985; and (5) highly localized users were generally excluded - e.g., taxicabs, and local paging.

  13. Land-mobile satellite communication system

    NASA Technical Reports Server (NTRS)

    Yan, Tsun-Yee (Inventor); Rafferty, William (Inventor); Dessouky, Khaled I. (Inventor); Wang, Charles C. (Inventor); Cheng, Unjeng (Inventor)

    1993-01-01

    A satellite communications system includes an orbiting communications satellite for relaying communications to and from a plurality of ground stations, and a network management center for making connections via the satellite between the ground stations in response to connection requests received via the satellite from the ground stations, the network management center being configured to provide both open-end service and closed-end service. The network management center of one embodiment is configured to provides both types of service according to a predefined channel access protocol that enables the ground stations to request the type of service desired. The channel access protocol may be configured to adaptively allocate channels to open-end service and closed-end service according to changes in the traffic pattern and include a free-access tree algorithm that coordinates collision resolution among the ground stations.

  14. Coherent Terahertz Wireless Signal Transmission Using Advanced Optical Fiber Communication Technology

    NASA Astrophysics Data System (ADS)

    Kanno, Atsushi; Kuri, Toshiaki; Morohashi, Isao; Hosako, Iwao; Kawanishi, Tetsuya; Yoshida, Yuki; Kitayama, Ken-ichi

    2015-02-01

    Coherent terahertz signal transmission with multilevel modulation and demodulation is demonstrated using an optical sub-harmonic IQ mixer (SHIQM), which consists of optical components in advanced optical fiber communication technologies. An optical-frequency-comb-employed signal generator is capable of vector modulation as well as frequency tunability. Digital signal processing (DSP) adopted from the recently developed optical digital coherent communication can easily demodulate multi-level modulated terahertz signals by using electrical heterodyning for intermediate-frequency (IF) down conversion. This technique is applicable for mobile backhauling in the next-generation mobile communication technology directly connected to an optical fiber network as a high-speed wireless transmission link.

  15. 5G: rethink mobile communications for 2020.

    PubMed

    Chih-Lin, I; Han, Shuangfeng; Xu, Zhikun; Sun, Qi; Pan, Zhengang

    2016-03-01

    The 5G network is anticipated to meet the challenging requirements of mobile traffic in the 2020s, which are characterized by super high data rate, low latency, high mobility, high energy efficiency and high traffic density. This paper provides an overview of China Mobile's 5G vision and potential solutions. Three key characteristics of 5G are analysed, i.e. super fast, soft and green. The main 5G R&D themes are further elaborated, which include five fundamental rethinkings of the traditional design methodologies. The 5G network design considerations are also discussed, with cloud radio access network, ultra-dense network, software defined network and network function virtualization examined as key potential solutions towards a green and soft 5G network. The paradigm shift to user-centric network operation from the traditional cell-centric operation is also investigated, where the decoupled downlink and uplink, control and data, and adaptive multiple connections provide sufficient means to achieve a user-centric 5G network with 'no more cells'. The software defined air interface is investigated under a uniform framework and can adaptively adapt the parameters to well satisfy various requirements in different 5G scenarios. PMID:26809577

  16. Space Mobile Network: A Near Earth Communication and Navigation Architecture

    NASA Technical Reports Server (NTRS)

    Israel, Dave J.; Heckler, Greg; Menrad, Robert J.

    2016-01-01

    This paper describes a Space Mobile Network architecture, the result of a recently completed NASA study exploring architectural concepts to produce a vision for the future Near Earth communications and navigation systems. The Space Mobile Network (SMN) incorporates technologies, such as Disruption Tolerant Networking (DTN) and optical communications, and new operations concepts, such as User Initiated Services, to provide user services analogous to a terrestrial smartphone user. The paper will describe the SMN Architecture, envisioned future operations concepts, opportunities for industry and international collaboration and interoperability, and technology development areas and goals.

  17. Integrating Communication, Computer Access, Environmental Control & Mobility.

    ERIC Educational Resources Information Center

    Romich, Barry A.; Vagnini, Carol B.

    Severely physically disabled people can be helped to reach their goals in educational, vocational, and personal pursuits through appropriate use of current technology. The expressive communication needs of people without functional speech can be met through an analysis of selection techniques, processing, and outputs. Examples of new systems…

  18. Mobile satellite service communications tests using a NASA satellite

    NASA Technical Reports Server (NTRS)

    Chambers, Katherine H.; Koschmeder, Louis A.; Hollansworth, James E.; ONeill, Jack; Jones, Robert E.; Gibbons, Richard C.

    1995-01-01

    Emerging applications of commercial mobile satellite communications include satellite delivery of compact disc (CD) quality radio to car drivers who can select their favorite programming as they drive any distance; transmission of current air traffic data to aircraft; and handheld communication of data and images from any remote corner of the world. Experiments with the enabling technologies and tests and demonstrations of these concepts are being conducted before the first satellite is launched by utilizing an existing NASA spacecraft.

  19. Payload system tradeoffs for mobile communications satellites

    NASA Technical Reports Server (NTRS)

    Moody, H. J.

    1990-01-01

    System level trade-offs carried out during Mobile Satellite (M-SAT) design activities are described. These trade-offs relate to the use of low level beam forming, flexible power and spectrum distribution, and selection of the number of beams to cover the service area. It is shown that antenna performance can be improved by sharing horns between beams using a low level beam forming network (BFN). Additionally, greatly increased power utilization is possible using a hybrid matrix concept to share power between beams.

  20. MSAT aeronautical mobile satellite communications terminal development

    NASA Technical Reports Server (NTRS)

    Sutherland, C. A.; Sydor, J. T.

    1995-01-01

    CAL has undertaken the development of a new aeronautical mobile terminal for the North American MSAT market. The terminal is to meet the MSAT standard and is aimed in particular at the 300,000 general aviation and business aircraft in North America. The terminals are therefore relatively low cost and small in size when compared to those currently being produced for larger airline aircraft. The terminal incorporates a top mounted mechanical steered antenna and a unique antenna steering subsystem. An overview of the terminal design is presented.

  1. Advanced Communications Architecture Demonstration Made Significant Progress

    NASA Technical Reports Server (NTRS)

    Carek, David Andrew

    2004-01-01

    Simulation for a ground station located at 44.5 deg latitude. The Advanced Communications Architecture Demonstration (ACAD) is a concept architecture to provide high-rate Ka-band (27-GHz) direct-to-ground delivery of payload data from the International Space Station. This new concept in delivering data from the space station targets scientific experiments that buffer data onboard. The concept design provides a method to augment the current downlink capability through the Tracking Data Relay Satellite System (TDRSS) Ku-band (15-GHz) communications system. The ACAD concept pushes the limits of technology in high-rate data communications for space-qualified systems. Research activities are ongoing in examining the various aspects of high-rate communications systems including: (1) link budget parametric analyses, (2) antenna configuration trade studies, (3) orbital simulations (see the preceding figure), (4) optimization of ground station contact time (see the following graph), (5) processor and storage architecture definition, and (6) protocol evaluations and dependencies.

  2. Open Innovation in Mobile and Convergent Communications

    NASA Astrophysics Data System (ADS)

    Jiménez, José

    The concept of open innovation seems to be very well suited to information and communication technologies. In the first place, as in any other field, the complexity of the new technology makes it necessary for companies to use ideas, processes and inventions from other players. As in any other field, we need the collaboration of the university, of SMEs, of inventors, and of the general public.

  3. Voice intelligibility in satellite mobile communications

    NASA Technical Reports Server (NTRS)

    Wishna, S.

    1973-01-01

    An amplitude control technique is reported that equalizes low level phonemes in a satellite narrow band FM voice communication system over channels having low carrier to noise ratios. This method presents at the transmitter equal amplitude phonemes so that the low level phonemes, when they are transmitted over the noisey channel, are above the noise and contribute to output intelligibility. The amplitude control technique provides also for squelching of noise when speech is not being transmitted.

  4. Communication services for advanced network applications.

    SciTech Connect

    Bresnahan, J.; Foster, I.; Insley, J.; Toonen, B.; Tuecke, S.

    1999-06-10

    Advanced network applications such as remote instrument control, collaborative environments, and remote I/O are distinguished by traditional applications such as videoconferencing by their need to create multiple, heterogeneous flows with different characteristics. For example, a single application may require remote I/O for raw datasets, shared controls for a collaborative analysis system, streaming video for image rendering data, and audio for collaboration. Furthermore, each flow can have different requirements in terms of reliability, network quality of service, security, etc. They argue that new approaches to communication services, protocols, and network architecture are required both to provide high-level abstractions for common flow types and to support user-level management of flow creation and quality. They describe experiences with the development of such applications and communication services.

  5. Daily Rhythms in Mobile Telephone Communication.

    PubMed

    Aledavood, Talayeh; López, Eduardo; Roberts, Sam G B; Reed-Tsochas, Felix; Moro, Esteban; Dunbar, Robin I M; Saramäki, Jari

    2015-01-01

    Circadian rhythms are known to be important drivers of human activity and the recent availability of electronic records of human behaviour has provided fine-grained data of temporal patterns of activity on a large scale. Further, questionnaire studies have identified important individual differences in circadian rhythms, with people broadly categorised into morning-like or evening-like individuals. However, little is known about the social aspects of these circadian rhythms, or how they vary across individuals. In this study we use a unique 18-month dataset that combines mobile phone calls and questionnaire data to examine individual differences in the daily rhythms of mobile phone activity. We demonstrate clear individual differences in daily patterns of phone calls, and show that these individual differences are persistent despite a high degree of turnover in the individuals' social networks. Further, women's calls were longer than men's calls, especially during the evening and at night, and these calls were typically focused on a small number of emotionally intense relationships. These results demonstrate that individual differences in circadian rhythms are not just related to broad patterns of morningness and eveningness, but have a strong social component, in directing phone calls to specific individuals at specific times of day. PMID:26390215

  6. Daily Rhythms in Mobile Telephone Communication

    PubMed Central

    Aledavood, Talayeh; López, Eduardo; Roberts, Sam G. B.; Reed-Tsochas, Felix; Moro, Esteban; Dunbar, Robin I. M.; Saramäki, Jari

    2015-01-01

    Circadian rhythms are known to be important drivers of human activity and the recent availability of electronic records of human behaviour has provided fine-grained data of temporal patterns of activity on a large scale. Further, questionnaire studies have identified important individual differences in circadian rhythms, with people broadly categorised into morning-like or evening-like individuals. However, little is known about the social aspects of these circadian rhythms, or how they vary across individuals. In this study we use a unique 18-month dataset that combines mobile phone calls and questionnaire data to examine individual differences in the daily rhythms of mobile phone activity. We demonstrate clear individual differences in daily patterns of phone calls, and show that these individual differences are persistent despite a high degree of turnover in the individuals’ social networks. Further, women’s calls were longer than men’s calls, especially during the evening and at night, and these calls were typically focused on a small number of emotionally intense relationships. These results demonstrate that individual differences in circadian rhythms are not just related to broad patterns of morningness and eveningness, but have a strong social component, in directing phone calls to specific individuals at specific times of day. PMID:26390215

  7. A satellite system for land-mobile communications in Europe

    NASA Technical Reports Server (NTRS)

    Bartholome, P.; Rogard, R.

    1988-01-01

    There exists a great unsatisified demand for land mobile communications in Europe, particularly in sectors of business activity such as the road transport industry. This demand could best be satisfied by means of satellite-based private networks providing voice and data communications in a hub configuration. The potential market is estimated to encompass several hundred thousand road vehicles and the transmission capacity required would be several thousand channels. ESA is currently demonstrating the potential of satellite communications for this type of application, using a system called PRODAT. System studies are being performed with the aim of defining the architecture of a regional satellite system for Europe.

  8. Satellite-aided mobile communications, experiments, applications and prospects

    NASA Technical Reports Server (NTRS)

    Anderson, R. E.; Frey, R. L.; Lewis, J. R.; Milton, R. T.

    1980-01-01

    NASA's ATS-series of satellites were used in a series of communications and position fixing experiments with automotive vehicles, ships and aircraft. Applications of the communications were demonstrated and evaluated for public services including law enforcement, search and rescue, and medical emergency, and for commercial uses in the land and maritime transportation industries. The technical success of the experiments and the demonstrated potential value of the communications prompted a study that concluded an operational satellite-aided system would be a valuable augmentation of planned trunking or cellular type terrestrial mobile radio telephone systems.

  9. A Model and Measure of Mobile Communication Competence

    ERIC Educational Resources Information Center

    Bakke, Emil

    2010-01-01

    This article deals with two studies that develop a measure and model of mobile communication competence (MCC). The first study examines the dimensionality of the measure by conducting an exploratory factor analysis on 350 students at a large university in the midwestern United States. Results identified six constructs across 24 items: willingness…

  10. The Role of Mobile Phones in Family Communication

    ERIC Educational Resources Information Center

    Devitt, Kerry; Roker, Debi

    2009-01-01

    Whilst there is a wealth of research into family communication and family relationships, there is little information about whether (and if so how) mobile phones have impacted on these processes. The authors' study involved individual semi-structured interviews with 60 families, including parents/carers and young people aged 11-17, to investigate…

  11. QoS management for the next mobile communication network

    NASA Astrophysics Data System (ADS)

    Wang, Hui; Lu, Jun; Yu, Jianwei; He, Feng

    2004-04-01

    With convergence of network technologies, future network infrastructure will be based on IP and traditional wireless/mobile networks will also evolve inevitably to a unified all-IP mobile internet which can support voice, data and video simultaneously. But, the pattern served by IP is best effort. So IP mobility and QoS management have been the main challenges of all-IP mobile networks. Based on Mobile IP, IP QoS protocol, etc, ... The paper brings forward an end-to-end QoS management solution for the next mobile communication network, introduces a terminology of QoS Agent Server (QAS), which acts as resource manage server and participate in dynamic Service Level Specification (SLS) negotiation with mobile hosts (MH) or other QAS. Taking advantage of the mechanisms, discussed the process of QoS manage to support mobile hosts' fast handoff between cells. Additionally, adopted and self-adaptive control algorithm for non-real time service on interior nodes. Finally, conclusions are given and possible future works are described.

  12. Coherent versus noncoherent signaling for satellite-aided mobile communications

    NASA Technical Reports Server (NTRS)

    Davarian, F.; Sumida, J.

    1986-01-01

    The use of coherent versus noncoherent communications is an unresolved issue for the mobile satellite community. Should one select the more robust but less efficient noncoherent strategy for communications over satellite-aided mobile channels, or does the introduction of a space platform in the mobile link improve signal stability (both amplitude and phase) such that conventional coherent schemes become attractive? This publication tries to answer some of the questions by discussing the results from experiments using a coherent QPSK receiver. The issues discussed include items such as the measured performance in Rician fading, the link error floor in a fading environment, etc. The results are compared and contrasted with that of a noncoherent limiter/discriminator FM receiver.

  13. Spread spectrum mobile communication experiment using ETS-V satellite

    NASA Technical Reports Server (NTRS)

    Ikegami, Tetsushi; Suzuki, Ryutaro; Kadowaki, Naoto; Taira, Shinichi; Sato, Nobuyasu

    1990-01-01

    The spread spectrum technique is attractive for application to mobile satellite communications, because of its random access capability, immunity to inter-system interference, and robustness to overloading. A novel direct sequence spread spectrum communication equipment is developed for land mobile satellite applications. The equipment is developed based on a matched filter technique to improve the initial acquisition performance. The data rate is 2.4 kilobits per sec. and the PN clock rate is 2.4552 mega-Hz. This equipment also has a function of measuring the multipath delay profile of land mobile satellite channel, making use of a correlation property of a PN code. This paper gives an outline of the equipment and the field test results with ETS-V satellite.

  14. The advanced use of mobile phones in five European countries.

    PubMed

    Fortunati, Leopoldina; Taipale, Sakari

    2014-06-01

    The paper explores the advanced users of mobile phones in Italy, France, Germany, Spain and the UK (EU5 countries) and aims to clarify the social meaning of advanced use. The mobile phone is seen as a strategic tool of social labour, whose capabilities are exploited to a different extent in the five studied countries. The analysis is based on a cross-national survey data collected in 2009 (N = 7,255). First, the results show that there are substantial differences in the advanced use of mobile phone and its predictors in Europe. Generally, only about one third of the studied mobile features are exploited. British and French people are the most advanced users, followed by German, Spanish and Italians. While Italians have stuck to early developed mobile phone features, Britons especially have continued to adopt the newer properties of the mobile phone. Second, the article shows that owing to the extensive under-utilization of its features, the mobile phone as a tool of social labour is efficiently exploited by only a small number of people. They, however, constitute technological vanguards that make use of the diverse features in different countries. This limited use of advanced features results in the new patterns of social stratification. PMID:24697752

  15. The application of mobile satellite services to emergency response communications

    NASA Technical Reports Server (NTRS)

    Freibaum, J.

    1980-01-01

    The application of an integrated satellite/terrestrial emergency response communications system in disaster relief operations is discussed. Large area coverage communications capability, full-time availability, a high degree of mobility, plus reliability, are pointed out as criteria for an effective emergency communications system. Response time is seen as a major factor determining the possible survival and/or protection of property. These criteria, can not be met by existing communications systems and complete blackouts were experienced during the past decades caused by either interruption or destruction of existing power lines, and overload or inadequacy of remaining lines. Several emergency cases, caused by either hurricanes, tornados, or floods, during which communication via satellite was instrumental to inform rescue and relief teams, are described in detail. Seismic Risk Maps and charts of Major Tectonic Plates Earthquake Epicenters are given, and it is noted that, 35 percent of the U.S. population is living in critical areas. National and international agreements for the implementation of a satellite-aided global Search and Rescue Program is mentioned. Technological and economic breakthroughs are still needed in large multibeam antennas, switching circuits, and low cost mobile ground terminals. A pending plan of NASA to initiate a multiservice program in 1982/83, with a Land Mobile Satellite capability operating in the 806 - 890 MHz band as a major element, may help to accelerate the needed breakthroughs.

  16. Potential markets for advanced satellite communications

    NASA Technical Reports Server (NTRS)

    Adamson, Steven; Roberts, David; Schubert, Leroy; Smith, Brian; Sogegian, Robert; Walters, Daniel

    1993-01-01

    This report identifies trends in the volume and type of traffic offered to the U.S. domestic communications infrastructure and extrapolates these trends through the year 2011. To describe how telecommunications service providers are adapting to the identified trends, this report assesses the status, plans, and capacity of the domestic communications infrastructure. Cable, satellite, and radio components of the infrastructure are examined separately. The report also assesses the following major applications making use of the infrastructure: (1) Broadband services, including Broadband Integrated Services Digital Network (BISDN), Switched Multimegabit Data Service (SMDS), and frame relay; (2) mobile services, including voice, location, and paging; (3) Very Small Aperture Terminals (VSAT), including mesh VSAT; and (4) Direct Broadcast Satellite (DBS) for audio and video. The report associates satellite implementation of specific applications with market segments appropriate to their features and capabilities. The volume and dollar value of these market segments are estimated. For the satellite applications able to address the needs of significant market segments, the report also examines the potential of each satellite-based application to capture business from alternative technologies.

  17. Potential markets for advanced satellite communications

    NASA Astrophysics Data System (ADS)

    Adamson, Steven; Roberts, David; Schubert, Leroy; Smith, Brian; Sogegian, Robert; Walters, Daniel

    1993-09-01

    This report identifies trends in the volume and type of traffic offered to the U.S. domestic communications infrastructure and extrapolates these trends through the year 2011. To describe how telecommunications service providers are adapting to the identified trends, this report assesses the status, plans, and capacity of the domestic communications infrastructure. Cable, satellite, and radio components of the infrastructure are examined separately. The report also assesses the following major applications making use of the infrastructure: (1) Broadband services, including Broadband Integrated Services Digital Network (BISDN), Switched Multimegabit Data Service (SMDS), and frame relay; (2) mobile services, including voice, location, and paging; (3) Very Small Aperture Terminals (VSAT), including mesh VSAT; and (4) Direct Broadcast Satellite (DBS) for audio and video. The report associates satellite implementation of specific applications with market segments appropriate to their features and capabilities. The volume and dollar value of these market segments are estimated. For the satellite applications able to address the needs of significant market segments, the report also examines the potential of each satellite-based application to capture business from alternative technologies.

  18. An integrated Ka/Ku-band payload for personal, mobile and private business communications

    NASA Technical Reports Server (NTRS)

    Hayes, Edward J.; Keelty, J. Malcolm

    1991-01-01

    The Canadian Department of Communications has been studying options for a government-sponsored demonstration payload to be launched before the end of the century. A summary of the proposed system concepts and network architectures for providing an advanced private business network service at Ku-band and personal and mobile communications at Ka-band is presented. The system aspects addressed include coverage patterns, traffic capacity, and grade of service, multiple access options as well as special problems, such as Doppler in mobile applications. Earth terminal types and the advanced payload concept proposed in a feasibility study for the demonstration mission are described. This concept is a combined Ka-band/Ku-band payload which incorporates a number of advanced satellite technologies including a group demodulator to convert single-channel-per-carrier frequency division multiple access uplink signals to a time division multiplex downlink, on-board signal regeneration, and baseband switching to support packet switched data operation. The on-board processing capability of the payload provides a hubless VSAT architecture which permits single-hop full mesh interconnectivity. The Ka-band and Ku-band portions of the payload are fully integrated through an on-board switch, thereby providing the capability for fully integrated services, such as using the Ku-band VSAT terminals as gateway stations for the Ka-band personal and mobile communications services.

  19. The ACTS Flight System - Cost-Effective Advanced Communications Technology. [Advanced Communication Technology Satellite

    NASA Technical Reports Server (NTRS)

    Holmes, W. M., Jr.; Beck, G. A.

    1984-01-01

    The multibeam communications package (MCP) for the Advanced Communications Technology Satellite (ACTS) to be STS-launched by NASA in 1988 for experimental demonstration of satellite-switched TDMA (at 220 Mbit/sec) and baseband-processor signal routing (at 110 or 27.5 Mbit/sec) is characterized. The developmental history of the ACTS, the program definition, and the spacecraft-bus and MCP parameters are reviewed and illustrated with drawings, block diagrams, and maps of the coverage plan. Advanced features of the MPC include 4.5-dB-noise-figure 30-GHz FET amplifiers and 20-GHz TWTA transmitters which provide either 40-W or 8-W RF output, depending on rain conditions. The technologies being tested in ACTS can give frequency-reuse factors as high as 20, thus greatly expanding the orbit/spectrum resources available for U.S. communications use.

  20. Study of LEO-SAT microwave link for broad-band mobile satellite communication system

    NASA Technical Reports Server (NTRS)

    Fujise, Masayuki; Chujo, Wataru; Chiba, Isamu; Furuhama, Yoji; Kawabata, Kazuaki; Konishi, Yoshihiko

    1993-01-01

    In the field of mobile satellite communications, a system based on low-earth-orbit satellites (LEO-SAT's) such as the Iridium system has been proposed. The LEO-SAT system is able to offer mobile telecommunication services in high-latitude areas. Rain degradation, fading and shadowing are also expected to be decreased when the system is operated at a high elevation angle. Furthermore, the propagation delay generated in the LEO-SAT system is less pronounced than that in the geostationary orbit satellite (GEO-SAT) system and, in voice services, the effect of the delay is almost negligible. We proposed a concept of a broad-band mobile satellite communication system with LEO-SAT's and Optical ISL. In that system, a fixed L-band (1.6/1.5 GHz) multibeam is used to offer narrow band service to the mobile terminals in the entire area covered by a LEO-SAT and steerable Ka-band (30/20 GHz) spot beams are used for the wide band service. In this paper, we present results of a study of LEO-SAT microwave link between a satellite and a mobile terminal for a broad-band mobile satellite communication system. First, the results of link budget calculations are presented and the antennas mounted on satellites are shown. For a future mobile antenna technology, we also show digital beamforming (DBF) techniques. DBF, together with modulation and/or demodulation, is becoming a key technique for mobile antennas with advanced functions such as antenna pattern calibration, correction, and radio interference suppression. In this paper, efficient DBF techniques for transmitting and receiving are presented. Furthermore, an adaptive array antenna system suitable for this LEO-SAT is presented.

  1. A wideband propagation simulator for high speed mobile radio communications

    NASA Astrophysics Data System (ADS)

    Busson, P.; Lejannic, J. C.; Elzein, G.; Citerne, J.

    1994-07-01

    Multipath, jamming, listening and detection are the main limitations for mobile radio communications. Spread spectrum techniques, especially frequency hopping, can be used to avoid these problems. Therefore, a wideband simulation for multipath mobile channels appeared the most appropriate evaluation technique. It also gives useful indications for system characteristic improvements. This paper presents the design and realization of a new UHF-VHF propagation simulator, which can be considered as an extended version of Bussgang's one. This frequency hopping simulator (up to 100,000 hops per second) is wideband thus capable to deal with spread spectrum signals. As it generates up to 16 paths, it can be used in almost all mobile radio propagation situations. Moreover, it is also able to simulate high mobile relative speeds up to 2000km/h such as air-air communication systems. This simulator can reproduce, in laboratory, 16 rays Rician or Rayleigh fading channels with a maximum time delay of about 15 ms. At the highest frequency of 1200 MHz, Doppler rates up to 2 kHz can be generated corresponding to vehicle speeds up to 2000 km/h. Let note that the Bussgang simulator was defined for narrowband and fixed radio communications. In both equipments, in-phase and quadrature signals are obtained using two numerical transversal filters. Simulation results were derived in various situations especially in terrestrial urban and suburban environments, where they could be compared with measurements. The main advantage of the simulator lies in its capacity to simulate the high speed and wideband mobile radio communication channels.

  2. The Globalstar mobile satellite system for worldwide personal communications

    NASA Technical Reports Server (NTRS)

    Wiedeman, Robert A.; Viterbi, Andrew J.

    1993-01-01

    Loral Aerospace Corporation along with Qualcomm Inc. have developed a satellite system which offers global mobile voice and data services to and from handheld and mobile user terminals with omni-directional antennas. By combining the use of low-earth orbit (LEO) satellites with existing terrestrial communications systems and innovative, highly efficient spread spectrum techniques, the Globalstar system provides users with low-cost, reliable communications throughout the world. The Globalstar space segment consists of a constellation of 48 LEO satellites in circular orbits with 750 NM (1389 km) altitude. Each satellite communicates with the mobile users via the satellite-user links and with gateway stations. The gateway stations handle the interface between the Globalstar network and the OSTN/PLMN systems. Globalstar transceivers are similar to currently proposed digital cellular telephones in size and have a serial number that will allow the end user to make and receive calls from or to that device anywhere in the world. The Globalstar system is designed to operate as a complement to existing local, long-distance, public, private and specialized telecommunications networks. Service is primarily designed to serve the rural and thin route communications needs of consumers, government users, and private networks.

  3. Why is CDMA the solution for mobile satellite communication

    NASA Technical Reports Server (NTRS)

    Gilhousen, Klein S.; Jacobs, Irwin M.; Padovani, Roberto; Weaver, Lindsay A.

    1989-01-01

    It is demonstrated that spread spectrum Code Division Multiple Access (CDMA) systems provide an economically superior solution to satellite mobile communications by increasing the system maximum capacity with respect to single channel per carrier Frequency Division Multiple Access (FDMA) systems. Following the comparative analysis of CDMA and FDMA systems, the design of a model that was developed to test the feasibility of the approach and the performance of a spread spectrum system in a mobile environment. Results of extensive computer simulations as well as laboratory and field tests results are presented.

  4. Monitoring Heart Disease and Diabetes with Mobile Internet Communications

    PubMed Central

    Mulvaney, David; Woodward, Bryan; Datta, Sekharjit; Harvey, Paul; Vyas, Anoop; Thakker, Bhaskar; Farooq, Omar; Istepanian, Robert

    2012-01-01

    A telemedicine system is described for monitoring vital signs and general health indicators of patients with cardiac and diabetic conditions. Telemetry from wireless sensors and readings from other instruments are combined into a comprehensive set of measured patient parameters. Using a combination of mobile device applications and web browser, the data can be stored, accessed, and displayed using mobile internet communications to the central server. As an extra layer of security in the data transmission, information embedded in the data is used in its verification. The paper highlights features that could be enhanced from previous systems by using alternative components or methods. PMID:23213330

  5. Close Relationships: A Study of Mobile Communication Records

    NASA Astrophysics Data System (ADS)

    Palchykov, Vasyl; Kertész, János; Dunbar, Robin; Kaski, Kimmo

    2013-05-01

    Mobile phone communication as digital service generates ever-increasing datasets of human communication actions, which in turn allow us to investigate the structure and evolution of social interactions and their networks. These datasets can be used to study the structuring of such egocentric networks with respect to the strength of the relationships by assuming direct dependence of the communication intensity on the strength of the social tie. Recently we have discovered that there are significant differences between the first and further "best friends" from the point of view of age and gender preferences. Here we introduce a control parameter p max based on the statistics of communication with the first and second "best friend" and use it to filter the data. We find that when p max is decreased the identification of the "best friend" becomes less ambiguous and the earlier observed effects get stronger, thus corroborating them.

  6. Structure and tie strengths in mobile communication networks.

    PubMed

    Onnela, J-P; Saramäki, J; Hyvönen, J; Szabó, G; Lazer, D; Kaski, K; Kertész, J; Barabási, A-L

    2007-05-01

    Electronic databases, from phone to e-mails logs, currently provide detailed records of human communication patterns, offering novel avenues to map and explore the structure of social and communication networks. Here we examine the communication patterns of millions of mobile phone users, allowing us to simultaneously study the local and the global structure of a society-wide communication network. We observe a coupling between interaction strengths and the network's local structure, with the counterintuitive consequence that social networks are robust to the removal of the strong ties but fall apart after a phase transition if the weak ties are removed. We show that this coupling significantly slows the diffusion process, resulting in dynamic trapping of information in communities and find that, when it comes to information diffusion, weak and strong ties are both simultaneously ineffective. PMID:17456605

  7. An advanced domestic satellite communications system

    NASA Technical Reports Server (NTRS)

    1980-01-01

    An updated traffic projection for U.S. domestic satellite communications service covering a period of 15 years; mid-1980 to mid-1995 was prepared. This model takes into account expected technology advances and reductions in transmission costs, legislative and regulatory changes permitting increased competition, and rising energy costs which will encourage more extensive substitution of telecommunications for travel. The historical development and current status of satellite systems are discussed as well as the characteristics of follow-on systems. Orbital arc utilization, spacecraft configuration for single shuttle launch, Earth station configuration, and system costs are examined. Areas which require technology development include multiple beam frequency reuse antennas, on-board switching, intersatellite links, and ka-band operation. Packing and deployment schemes for enclosing the satellite within the shuttle orbiter bay must also be devised.

  8. FEC decoder design optimization for mobile satellite communications

    NASA Technical Reports Server (NTRS)

    Roy, Ashim; Lewi, Leng

    1990-01-01

    A new telecommunications service for location determination via satellite is being proposed for the continental USA and Europe, which provides users with the capability to find the location of, and communicate from, a moving vehicle to a central hub and vice versa. This communications system is expected to operate in an extremely noisy channel in the presence of fading. In order to achieve high levels of data integrity, it is essential to employ forward error correcting (FEC) encoding and decoding techniques in such mobile satellite systems. A constraint length k = 7 FEC decoder has been implemented in a single chip for such systems. The single chip implementation of the maximum likelihood decoder helps to minimize the cost, size, and power consumption, and improves the bit error rate (BER) performance of the mobile earth terminal (MET).

  9. FEC decoder design optimization for mobile satellite communications

    NASA Astrophysics Data System (ADS)

    Roy, Ashim; Lewi, Leng

    A new telecommunications service for location determination via satellite is being proposed for the continental USA and Europe, which provides users with the capability to find the location of, and communicate from, a moving vehicle to a central hub and vice versa. This communications system is expected to operate in an extremely noisy channel in the presence of fading. In order to achieve high levels of data integrity, it is essential to employ forward error correcting (FEC) encoding and decoding techniques in such mobile satellite systems. A constraint length k = 7 FEC decoder has been implemented in a single chip for such systems. The single chip implementation of the maximum likelihood decoder helps to minimize the cost, size, and power consumption, and improves the bit error rate (BER) performance of the mobile earth terminal (MET).

  10. RF Technologies for Advancing Space Communication Infrastructure

    NASA Technical Reports Server (NTRS)

    Romanofsky, Robert R.; Bibyk, Irene K.; Wintucky, Edwin G.

    2006-01-01

    This paper will address key technologies under development at the NASA Glenn Research Center designed to provide architecture-level impacts. Specifically, we will describe deployable antennas, a new type of phased array antenna and novel power amplifiers. The evaluation of architectural influence can be conducted from two perspectives where said architecture can be analyzed from either the top-down to determine the areas where technology improvements will be most beneficial or from the bottom-up where each technology s performance advancement can affect the overall architecture s performance. This paper will take the latter approach with focus on some technology improvement challenges and address architecture impacts. For example, using data rate as a performance metric, future exploration scenarios are expected to demand data rates possibly exceeding 1 Gbps. To support these advancements in a Mars scenario, as an example, Ka-band and antenna aperture sizes on the order of 10 meters will be required from Mars areostationary platforms. Key technical challenges for a large deployable antenna include maximizing the ratio of deployed-to-packaged volume, minimizing aerial density, maintaining RMS surface accuracy to within 1/20 of a wavelength or better, and developing reflector rigidization techniques. Moreover, the high frequencies and large apertures manifest a new problem for microwave engineers that are familiar to optical communications specialists: pointing. The fine beam widths and long ranges dictate the need for electronic or mechanical feed articulation to compensate for spacecraft attitude control limitations.

  11. Trellis-coded CPM for satellite-based mobile communications

    NASA Technical Reports Server (NTRS)

    Abrishamkar, Farrokh; Biglieri, Ezio

    1988-01-01

    Digital transmission for satellite-based land mobile communications is discussed. To satisfy the power and bandwidth limitations imposed on such systems, a combination of trellis coding and continuous-phase modulated signals are considered. Some schemes based on this idea are presented, and their performance is analyzed by computer simulation. The results obtained show that a scheme based on directional detection and Viterbi decoding appears promising for practical applications.

  12. First satellite mobile communication trials using BLQS-CDMA

    NASA Technical Reports Server (NTRS)

    Luzdemateo, Maria; Johns, Simon; Dothey, Michel; Vanhimbeeck, Carl; Deman, Ivan; Wery, Bruno

    1993-01-01

    In this paper, technical results obtained in the first MSBN Land mobile technical trial are reported. MSBN (Mobile Satellite Business Network) is a new program undertaken by the European Space Agency (ESA) to promote mobile satellite communication in Europe, in particular voice capability. The first phase of the MSBN system implementation plan is an experimental phase. Its purpose is to evaluate through field experiments the performance of the MSBN system prior to finalization of its specifications. Particularly, the objective is to verify in the field and possibly improve the performance of the novel satellite access technique BLQS-CDMA (Band Limited Quasi-Synchronous-Code Division Multiple Access), which is proposed as baseline for the MSBN.

  13. Continuous zoom antenna for mobile visible light communication.

    PubMed

    Zhang, Xuebin; Tang, Yi; Cui, Lu; Bai, Tingzhu

    2015-11-10

    In this paper, we design a continuous zoom antenna for mobile visible light communication (VLC). In the design, a right-angle reflecting prism was adopted to fold the space optical path, thus decreasing the antenna thickness. The surface of each lens in the antenna is spherical, and the system cost is relatively low. Simulation results indicated that the designed system achieved the following performance: zoom ratio of 2.44, field of view (FOV) range of 18°-48°, system gain of 16.8, and system size of 18 mm×6  mm. Finally, we established an indoor VLC system model in a room the size of 5  m ×5  m ×3  m and compared the detection results of the zoom antenna and fixed-focus antenna obtained in a multisource communication environment, a mobile VLC environment, and a multiple-input multiple-output communication environment. The simulation results indicated that the continuous zoom antenna could realize large FOV and high gain. Moreover, the system showed improved stability, mobility, and environmental applicability. PMID:26560793

  14. Mobile satellite communications technology - A summary of NASA activities

    NASA Technical Reports Server (NTRS)

    Dutzi, E. J.; Knouse, G. H.

    1986-01-01

    Studies in recent years indicate that future high-capacity mobile satellite systems are viable only if certain high-risk enabling technologies are developed. Accordingly, NASA has structured an advanced technology development program aimed at efficient utilization of orbit, spectrum, and power. Over the last two years, studies have concentrated on developing concepts and identifying cost drivers and other issues associated with the major technical areas of emphasis: vehicle antennas, speech compression, bandwidth-efficient digital modems, network architecture, mobile satellite channel characterization, and selected space segment technology. The program is now entering the next phase - breadboarding, development, and field experimentation.

  15. A system architecture for an advanced Canadian wideband mobile satellite system

    NASA Technical Reports Server (NTRS)

    Takats, P.; Keelty, M.; Moody, H.

    1993-01-01

    In this paper, the system architecture for an advanced Canadian ka-band geostationary mobile satellite system is described, utilizing hopping spot beams to support a 256 kbps wideband service for both N-ISDN and packet-switched interconnectivity to small briefcase-size portable and mobile terminals. An assessment is given of the technical feasibility of the satellite payload and terminal design in the post year 2000 timeframe. The satellite payload includes regeneration and on-board switching to permit single hop interconnectivity between mobile terminals. The mobile terminal requires antenna tracking and platform stabilization to ensure acquisition of the satellite signal. The potential user applications targeted for this wideband service includes: home-office, multimedia, desk-top (PC) videoconferencing, digital audio broadcasting, single and multi-user personal communications.

  16. Toward user mobility for OFDM-based visible light communications.

    PubMed

    Hong, Yang; Chen, Lian-Kuan

    2016-08-15

    We propose and experimentally demonstrate a mobile visible light communications (mobi-VLC) transmission system. The impact of user mobility on the performance of the mobi-VLC system is characterized, and we propose the use of the channel-independent orthogonal circulant matrix transform (OCT) precoding to combat the packet loss performance degradation induced by mobility. A mobile user terminal is used to detect the signal from a blue laser placed at 1 m away from the moving track. Various moving speeds (20, 40, 60, and 80  cm/s) and lateral moving distances (30, 40, and 50 cm) of the user terminal are investigated. The effectiveness of the OCT precoding is evaluated by the comparison with the conventional orthogonal frequency division multiplexing (OFDM) scheme and the adaptive-loaded discrete multi-tone (DMT) scheme. Experimental results show that the system performance degrades with the increase in user mobility speed and in moving distance. Furthermore, the OCT precoding provides performance improvement that is superior over that of conventional OFDM schemes, and it exhibits lower packet loss rate than that of adaptive-loaded DMT. No packet loss for 300  Mb/s transmission is achieved with a 30 cm lateral moving distance at 20  cm/s. PMID:27519083

  17. Aeronautical Mobile Airport Communications System (AeroMACS)

    NASA Technical Reports Server (NTRS)

    Budinger, James M.; Hall, Edward

    2011-01-01

    To help increase the capacity and efficiency of the nation s airports, a secure wideband wireless communications system is proposed for use on the airport surface. This paper provides an overview of the research and development process for the Aeronautical Mobile Airport Communications System (AeroMACS). AeroMACS is based on a specific commercial profile of the Institute of Electrical and Electronics Engineers (IEEE) 802.16 standard known as Wireless Worldwide Interoperability for Microwave Access or WiMAX (WiMax Forum). The paper includes background on the need for global interoperability in air/ground data communications, describes potential AeroMACS applications, addresses allocated frequency spectrum constraints, summarizes the international standardization process, and provides findings and recommendations from the world s first AeroMACS prototype implemented in Cleveland, Ohio, USA.

  18. Advanced Manufacturing Training: Mobile Learning Labs

    ERIC Educational Resources Information Center

    Vukich, John C.; Ackerman, Amanda A.

    2010-01-01

    Across Colorado, manufacturing employers forecast an on-going need not only for workers who are interested in career opportunities but who are prepared to enter the advanced manufacturing industry with the necessary high-tech skills. Additionally, employers report concerns about replacing retiring workers that take with them decades of…

  19. Advanced colour processing for mobile devices

    NASA Astrophysics Data System (ADS)

    Gillich, Eugen; Dörksen, Helene; Lohweg, Volker

    2015-02-01

    Mobile devices such as smartphones are going to play an important role in professionally image processing tasks. However, mobile systems were not designed for such applications, especially in terms of image processing requirements like stability and robustness. One major drawback is the automatic white balance, which comes with the devices. It is necessary for many applications, but of no use when applied to shiny surfaces. Such an issue appears when image acquisition takes place in differently coloured illuminations caused by different environments. This results in inhomogeneous appearances of the same subject. In our paper we show a new approach for handling the complex task of generating a low-noise and sharp image without spatial filtering. Our method is based on the fact that we analyze the spectral and saturation distribution of the channels. Furthermore, the RGB space is transformed into a more convenient space, a particular HSI space. We generate the greyscale image by a control procedure that takes into account the colour channels. This leads in an adaptive colour mixing model with reduced noise. The results of the optimized images are used to show how, e. g., image classification benefits from our colour adaptation approach.

  20. Advanced Fuzzy Potential Field Method for Mobile Robot Obstacle Avoidance

    PubMed Central

    Park, Jong-Wook; Kwak, Hwan-Joo; Kang, Young-Chang; Kim, Dong W.

    2016-01-01

    An advanced fuzzy potential field method for mobile robot obstacle avoidance is proposed. The potential field method primarily deals with the repulsive forces surrounding obstacles, while fuzzy control logic focuses on fuzzy rules that handle linguistic variables and describe the knowledge of experts. The design of a fuzzy controller—advanced fuzzy potential field method (AFPFM)—that models and enhances the conventional potential field method is proposed and discussed. This study also examines the rule-explosion problem of conventional fuzzy logic and assesses the performance of our proposed AFPFM through simulations carried out using a mobile robot. PMID:27123001

  1. Advanced Fuzzy Potential Field Method for Mobile Robot Obstacle Avoidance.

    PubMed

    Park, Jong-Wook; Kwak, Hwan-Joo; Kang, Young-Chang; Kim, Dong W

    2016-01-01

    An advanced fuzzy potential field method for mobile robot obstacle avoidance is proposed. The potential field method primarily deals with the repulsive forces surrounding obstacles, while fuzzy control logic focuses on fuzzy rules that handle linguistic variables and describe the knowledge of experts. The design of a fuzzy controller--advanced fuzzy potential field method (AFPFM)--that models and enhances the conventional potential field method is proposed and discussed. This study also examines the rule-explosion problem of conventional fuzzy logic and assesses the performance of our proposed AFPFM through simulations carried out using a mobile robot. PMID:27123001

  2. Plan of advanced satellite communication experiments using ETS-6

    NASA Technical Reports Server (NTRS)

    Ikegami, Tetsushi

    1989-01-01

    In 1992, an Engineering Test Satellite 6 is scheduled to be launched by an H-2 rocket. The missions of ETS-6 are to establish basic technologies of inter-satellite communications using S-band, millimeter waves and optical beams and of fixed and mobile satellite communications using multibeam antenna on board the satellite. A plan of the experiments is introduced.

  3. The Advanced Communication Technology Satellite and ISDN

    NASA Technical Reports Server (NTRS)

    Lowry, Peter A.

    1996-01-01

    This paper depicts the Advanced Communication Technology Satellite (ACTS) system as a global central office switch. The ground portion of the system is the collection of earth stations or T1-VSAT's (T1 very small aperture terminals). The control software for the T1-VSAT's resides in a single CPU. The software consists of two modules, the modem manager and the call manager. The modem manager (MM) controls the RF modem portion of the T1-VSAT. It processes the orderwires from the satellite or from signaling generated by the call manager (CM). The CM controls the Recom Laboratories MSPs by receiving signaling messages from the stacked MSP shelves ro units and sending appropriate setup commands to them. There are two methods used to setup and process calls in the CM; first by dialing up a circuit using a standard telephone handset or, secondly by using an external processor connected to the CPU's second COM port, by sending and receiving signaling orderwires. It is the use of the external processor which permits the ISDN (Integrated Services Digital Network) Signaling Processor to implement ISDN calls. In August 1993, the initial testing of the ISDN Signaling Processor was carried out at ACTS System Test at Lockheed Marietta, Princeton, NJ using the spacecraft in its test configuration on the ground.

  4. Interference Analysis for an Aeronautical Mobile Airport Communications System

    NASA Technical Reports Server (NTRS)

    Wilson, Jeffrey D.; Kerczewski, Robert J.

    2011-01-01

    The next generation of aeronautical communications for airport surface applications has been identified through a NASA research program and an international collaborative future communications study. The result, endorsed by both the United States and European regulatory agencies is called AeroMACS (Aeronautical Mobile Airport Communications System) and is based upon the IEEE 802.16e mobile wireless standard. Coordinated efforts to develop appropriate aviation standards for the AeroMACS system are now underway within RTCA (United States) and Eurocae (Europe). AeroMACS will be implemented in a recently allocated frequency band, 5091-5150 MHz. As this band is also occupied by fixed satellite service uplinks, AeroMACS must be designed to avoid interference with this incumbent service. The aspects of AeroMACS operation that present potential interference to the fixed satellite service are under analysis in order to enable the definition of standards that assure that such interference will be avoided. The NASA Glenn Research Center has been involved in this analysis, and the first results of modeling and simulation efforts directed at this analysis are the subject of this presentation.

  5. Interference Analysis for an Aeronautical Mobile Airport Communications System

    NASA Technical Reports Server (NTRS)

    Wilson, Jeffrey D.; Kercewski, Robert J.

    2010-01-01

    The next generation of aeronautical communications for airport surface applications has been identified through a NASA research program and an international collaborative future communications study. The result, endorsed by both the United States and European regulatory agencies is called AeroMACS (Aeronautical Mobile Airport Communications System) and is based upon the IEEE 802.16e mobile wireless standard. Coordinated efforts to develop appropriate aviation standards for the AeroMACS system are now underway within RTCA (United States) and Eurocae (Europe). AeroMACS will be implemented in a recently allocated frequency band, 5091- 5150 MHz. As this band is also occupied by fixed satellite service uplinks, AeroMACS must be designed to avoid interference with this incumbent service. The aspects of AeroMACS operation that present potential interference to the fixed satellite service are under analysis in order to enable the definition of standards that assure that such interference will be avoided. The NASA Glenn Research Center has been involved in this analysis, and the first results of modeling and simulation efforts directed at this analysis are the subject of this paper.12

  6. Advancing Instructional Communication: Integrating a Biosocial Approach

    ERIC Educational Resources Information Center

    Horan, Sean M.; Afifi, Tamara D.

    2014-01-01

    Celebrating 100 years of the National Communication Association necessitates that, as we commemorate our past, we also look toward our future. As part of a larger conversation about the future of instructional communication, this essay reinvestigates the importance of integrating biosocial approaches into instructional communication research. In…

  7. DIANE: Advanced system for mobile neutron radiology

    NASA Astrophysics Data System (ADS)

    Dance, W. E.; Huriet, J. R.; Cluzeau, S.; Mast, H.-U.; Albisu, F.

    1989-04-01

    Development of a new neutron radiology system, DIANE, is underway which will provide a ten-fold improvement in image-acquisition speed over presently operating mobile systems, insuring greater inspection throughput for production applications. Based on a 10 12 n/s sealed-tube (D-T) neutron generator under development by Sodern, on LTV's neutron moderator/collimator and electronic imaging systems and on robotic and safety systems being developed by IABG and Sener, the DIANE concept is that of a complete facility for on-site neutron radiography or radioscopy. The LTV components, which provide film or electronic imaging, including digital processing of 12-bit images, have been demonstrated in three basic systems now operating with Kaman A-711 neutron generators, including one operating in IABG's facilities. Sodern has fabricated a prototype neutron generator tube, the TN 46, for emission of 10 11 n/s over 1000 to 1500 hours, at 250 kV and 2 mA in the ion beam.

  8. Advances in terahertz communications accelerated by photonics

    NASA Astrophysics Data System (ADS)

    Nagatsuma, Tadao; Ducournau, Guillaume; Renaud, Cyril C.

    2016-06-01

    Almost 15 years have passed since the initial demonstrations of terahertz (THz) wireless communications were made using both pulsed and continuous waves. THz technologies are attracting great interest and are expected to meet the ever-increasing demand for high-capacity wireless communications. Here, we review the latest trends in THz communications research, focusing on how photonics technologies have played a key role in the development of first-age THz communication systems. We also provide a comparison with other competitive technologies, such as THz transceivers enabled by electronic devices as well as free-space lightwave communications.

  9. Method for Evaluation of Outage Probability on Random Access Channel in Mobile Communication Systems

    NASA Astrophysics Data System (ADS)

    Kollár, Martin

    2012-05-01

    In order to access the cell in all mobile communication technologies a so called random-access procedure is used. For example in GSM this is represented by sending the CHANNEL REQUEST message from Mobile Station (MS) to Base Transceiver Station (BTS) which is consequently forwarded as an CHANNEL REQUIRED message to the Base Station Controller (BSC). If the BTS decodes some noise on the Random Access Channel (RACH) as random access by mistake (so- called ‘phantom RACH') then it is a question of pure coincidence which èstablishment cause’ the BTS thinks to have recognized. A typical invalid channel access request or phantom RACH is characterized by an IMMEDIATE ASSIGNMENT procedure (assignment of an SDCCH or TCH) which is not followed by sending an ESTABLISH INDICATION from MS to BTS. In this paper a mathematical model for evaluation of the Power RACH Busy Threshold (RACHBT) in order to guaranty in advance determined outage probability on RACH is described and discussed as well. It focuses on Global System for Mobile Communications (GSM) however the obtained results can be generalized on remaining mobile technologies (ie WCDMA and LTE).

  10. Security Aspects of Smart Cards vs. Embedded Security in Machine-to-Machine (M2M) Advanced Mobile Network Applications

    NASA Astrophysics Data System (ADS)

    Meyerstein, Mike; Cha, Inhyok; Shah, Yogendra

    The Third Generation Partnership Project (3GPP) standardisation group currently discusses advanced applications of mobile networks such as Machine-to-Machine (M2M) communication. Several security issues arise in these contexts which warrant a fresh look at mobile networks’ security foundations, resting on smart cards. This paper contributes a security/efficiency analysis to this discussion and highlights the role of trusted platform technology to approach these issues.

  11. More About Lens Antenna For Mobile/Satellite Communication

    NASA Technical Reports Server (NTRS)

    Rahmat-Samii, Y.; Bodnar, D. G.; Rainer, B. K.

    1990-01-01

    Report presents additional details of design of proposed phased-array antenna described in "Lens Antenna for Mobile/Satellite Communication" (NPO-16948). Intended to be compact and to lie flat on top of vehicle on ground. Transmits and receives circularly polarized radiation in frequency ranges of 821 to 825 MHz and 860 to 870 MHz. Transmitting and receiving beams electronically steerable to any of 48 evenly spaced directions to provide complete azimuth coverage, and would be fixed, but wide, in elevation, to provide coverage at elevation angles from 20 degrees to 60 degrees.

  12. Omni-directional L-band antenna for mobile communications

    NASA Technical Reports Server (NTRS)

    Kim, C. S.; Moldovan, N.; Kijesky, J.

    1988-01-01

    The principle and design of an L-band omni-directional mobile communication antenna are discussed. The antenna is a circular wave guide aperture with hybrid circuits attached to higher order mode excitation. It produces polarized and symmetric two split beams in elevation. The circular waveguide is fed by eight probes with a 90 degree phase shift between their inputs. Radiation pattern characteristics are controlled by adjusting the aperture diameter and mode excitation. This antenna satisfies gain requirements as well as withstanding the harsh environment.

  13. Omni-directional L-band antenna for mobile communications

    NASA Astrophysics Data System (ADS)

    Kim, C. S.; Moldovan, N.; Kijesky, J.

    1988-05-01

    The principle and design of an L-band omni-directional mobile communication antenna are discussed. The antenna is a circular wave guide aperture with hybrid circuits attached to higher order mode excitation. It produces polarized and symmetric two split beams in elevation. The circular waveguide is fed by eight probes with a 90 degree phase shift between their inputs. Radiation pattern characteristics are controlled by adjusting the aperture diameter and mode excitation. This antenna satisfies gain requirements as well as withstanding the harsh environment.

  14. Advanced Shipboard Communications Demonstrations with ACTS

    NASA Technical Reports Server (NTRS)

    Axford, Roy A.; Jedrey, Thomas C.; Rupar, Michael A.

    2000-01-01

    For ships at sea. satellites provide the only option for high data rate (HDR), long haul communications. Furthermore the demand for HDR satellite communications (SATCOM) for military and commercial ships. and other offshore platforms is increasing. Presently the bulk of this maritime HDR SATCOM connectivity is provided via C-band and X-band. However, the shipboard antenna sizes required to achieve a data rate of, say T 1 (1.544 Mbps) with present C-/X-band SATCOM systems range from seven to ten feet in diameter. This limits the classes of ships to which HDR services can be provided to those which are large enough to accommodate the massive antennas. With its high powered K/Ka-band spot beams, the National Aeronautics and Space Administration's (NASA) Advanced Communications Technology Satellite (ACTS) was able to provide T I and higher rate services to ships at sea using much smaller shipboard antennas. This paper discusses three shipboard HDR SATCOM demonstrations that were conducted with ACTS between 1996 and 1998. The first demonstration involved a 2 Mbps link provided to the seismic survey ship MN Geco Diamond equipped with a 16-inch wide, 4.5-inch tall, mechanically steered slotted waveguide array antenna developed by the Jet Propulsion Laboratory. In this February 1996 demonstration ACTS allowed supercomputers ashore to process Geco Diamond's voluminous oceanographic seismic data in near real time. This capability allowed the ship to adjust its search parameters on a daily basis based on feedback from the processed data, thereby greatly increasing survey efficiency. The second demonstration was conducted on the US Navy cruiser USS Princeton (CG 59) with the same antenna used on Geco Diamond. Princeton conducted a six-month (January-July 1997) Western Hemisphere solo deployment during which time T1 connectivity via ACTS provided the ship with a range of valuable tools for operational, administrative and quality-of-life tasks. In one instance, video

  15. Design for Social Presence and Exploring Its Mediating Effect in Mobile Data Communication Services

    ERIC Educational Resources Information Center

    Ogara, Solomon Omondi

    2011-01-01

    The mobility, flexibility, convenience, and ubiquity of mobile data services (MDS) have contributed to their enormous growth and popularity with users. MDS allow users to communicate through mobile texting (mTexting), mobile Instant Messaging (mIM), multimedia messaging services (MMS), and email. A unique feature of MDS that enhances its…

  16. Radial microstrip slotline feed network for circular mobile communications array

    NASA Astrophysics Data System (ADS)

    Simons, Rainee N.; Kelly, Eron S.; Lee, Richard Q.; Taub, Susan R.

    1994-04-01

    In mobile and satellite communications there is a need for low cost and low profile antennas which have a toroidal pattern. Antennas that have been developed for mobile communications include a L-Band electronically steered stripline phased array, a Ka-Band mechanically steered elliptical reflector antenna and a Ka-Band printed dipole. In addition, a L-Band mechanically steered microstrip array, a L-Band microstrip phased array tracking antenna for mounting on a car roof and an X-Band radial line slotted waveguide antenna have been demonstrated. In the above electronically scanned printed arrays, the individual element radiates normally to the plane of the array and hence require a phase shifter to scan the beam towards the horizon. Scanning in the azimuth is by mechanical or electronic steering. An alternate approach is to mount microstrip patch radiators on the surface of a cone to achieve the required elevation angle. The array then scans in the azimuth by beam switching.

  17. Radial microstrip slotline feed network for circular mobile communications array

    NASA Technical Reports Server (NTRS)

    Simons, Rainee N.; Kelly, Eron S.; Lee, Richard Q.; Taub, Susan R.

    1994-01-01

    In mobile and satellite communications there is a need for low cost and low profile antennas which have a toroidal pattern. Antennas that have been developed for mobile communications include a L-Band electronically steered stripline phased array, a Ka-Band mechanically steered elliptical reflector antenna and a Ka-Band printed dipole. In addition, a L-Band mechanically steered microstrip array, a L-Band microstrip phased array tracking antenna for mounting on a car roof and an X-Band radial line slotted waveguide antenna have been demonstrated. In the above electronically scanned printed arrays, the individual element radiates normally to the plane of the array and hence require a phase shifter to scan the beam towards the horizon. Scanning in the azimuth is by mechanical or electronic steering. An alternate approach is to mount microstrip patch radiators on the surface of a cone to achieve the required elevation angle. The array then scans in the azimuth by beam switching.

  18. The Mobile College Community: A Study of Adult Learners' Adoption and Use of Digital Communication Technologies on the Campuses of Florida's Community Colleges

    ERIC Educational Resources Information Center

    Weidert, John William

    2012-01-01

    Rapid advancements in technology and the proliferation of mobile communication devices available in the marketplace require that community college administrators and teachers better understand levels of digital communication technology adoption and how adult learners currently use them. Such an understanding is necessary to developing the…

  19. Advances in MMIC technology for communications satellites

    NASA Astrophysics Data System (ADS)

    Leonard, Regis F.

    1992-03-01

    This paper discusses NASA Lewis Research Center's program for development of monolithic microwave integrated circuits (MMIC) for application in space communications. Emphasis will be on the improved performance in power amplifiers and low noise receivers which has been made possible by the development of new semiconductor materials and devices. Possible applications of high temperature superconductivity for space communications will also be presented.

  20. Evaluation of mobility impacts of advanced information systems

    SciTech Connect

    Peeta, S.; Poonuru, K.; Sinha, K.

    2000-06-01

    Advanced technologies under the aegis of advanced traveler information systems and advanced traffic management systems are being employed to address the debilitating traffic congestion problem. Broadly identified under the label intelligent transportation systems (ITS), they focus on enhancing the efficiency of the existing roadway utilization. Though ITS has transitioned from the conceptual framework stage to the operational test phase that analyzes real-world feasibility, studies that systematically quantify the multidimensional real-world impacts of these technologies in terms of mobility, safety, and air quality, are lacking. This paper proposes a simulation-based framework to address the mobility impacts of these technologies through the provision of information to travelers. The information provision technologies are labeled as advanced information systems (AIS), and include pretrip information, en route information, variable message signs, and combinations thereof. The primary focus of the paper is to evaluate alternative AIS technologies using the heavily traveled Borman Expressway corridor in northwestern Indiana as a case study. Simulation results provide insights into the mobility impacts of AIS technologies, and contrast the effectiveness of alternative information provision sources and strategies.

  1. Propagation issues for emerging mobile and portable communications: A systems perspective

    NASA Technical Reports Server (NTRS)

    Golshan, Nasser

    1993-01-01

    The viewpoint of a system engineer regarding the format of propagation information and models suitable for the design of mobile and portable satellite communications systems for the following services: audio broadcast, two way voice, and packet data is presented. Topics covered include: propagation impairments for portable indoor reception in satellite communications systems; propagation impairments and mitigation techniques for mobile satellite communications systems; characterization of mobile satellite communications channels in the presence of roadside blockage when interleaving and FEC coding are implemented; characterization of short-term mobile satellite signal variations; and characterization of long-term signal variations.

  2. 77 FR 35336 - Privacy and Security of Information Stored on Mobile Communications Devices

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-06-13

    ... Electronic Filing of Documents in Rulemaking Proceedings, 63 FR 24121 (1998). Electronic Filers: Comments may.... Indeed, in some respects, mobile communications devices are becoming more like computers,...

  3. Development of an advanced mobile base for personal mobility and manipulation appliance generation II robotic wheelchair

    PubMed Central

    Wang, Hongwu; Candiotti, Jorge; Shino, Motoki; Chung, Cheng-Shiu; Grindle, Garrett G.; Ding, Dan; Cooper, Rory A.

    2013-01-01

    Background This paper describes the development of a mobile base for the Personal Mobility and Manipulation Appliance Generation II (PerMMA Gen II robotic wheelchair), an obstacle-climbing wheelchair able to move in structured and unstructured environments, and to climb over curbs as high as 8 inches. The mechanical, electrical, and software systems of the mobile base are presented in detail, and similar devices such as the iBOT mobility system, TopChair, and 6X6 Explorer are described. Findings The mobile base of PerMMA Gen II has two operating modes: “advanced driving mode” on flat and uneven terrain, and “automatic climbing mode” during stair climbing. The different operating modes are triggered either by local and dynamic conditions or by external commands from users. A step-climbing sequence, up to 0.2 m, is under development and to be evaluated via simulation. The mathematical model of the mobile base is introduced. A feedback and a feed-forward controller have been developed to maintain the posture of the passenger when driving over uneven surfaces or slopes. The effectiveness of the controller has been evaluated by simulation using the open dynamics engine tool. Conclusion Future work for PerMMA Gen II mobile base is implementation of the simulation and control on a real system and evaluation of the system via further experimental tests. PMID:23820149

  4. 75 FR 8112 - In the Matter of Certain Mobile Telephones and Wireless Communication Devices Featuring Digital...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-02-23

    ... Cameras, and Components Thereof; Notice of Investigation AGENCY: U.S. International Trade Commission... communication devices featuring digital cameras, and components thereof by reason of infringement of certain... mobile telephones or wireless communication devices featuring digital cameras, or ] components...

  5. A Course and Curriculum in Advanced Technical Communication.

    ERIC Educational Resources Information Center

    Farkas, David

    A course in advanced technical communication was developed at West Virginia University for upper-division students in engineering and the sciences and those planning careers in technical communication. The first four weeks of the semester are spent copy editing, with the students learning to use standard editing marks and keeping an editor's style…

  6. Advanced technology for space communications, tracking, and robotic sensors

    NASA Technical Reports Server (NTRS)

    Krishen, Kumar

    1989-01-01

    Technological advancements in tracking, communications, and robotic vision sensors are reviewed. The development of communications systems for multiple access, broadband, high data rate, and efficient operation is discussed. Consideration is given to the Tracking and Data Relay Satellite systems, GPS, and communications and tracking systems for the Space Shuttle and the Space Station. The use of television, laser, and microwave sensors for robotics and technology for autonomous rendezvous and docking operations are examined.

  7. Robust and Cost-Efficient Communication Based on SNMP in Mobile Networks

    NASA Astrophysics Data System (ADS)

    Ryu, Sang-Hoon; Baik, Doo-Kwon

    A main challenge in the design of this mobile network is the development of dynamic routing protocols that can efficiently find routes between two communicating nodes. Multimedia streaming services are receiving considerable interest in the mobile network business. An entire mobile network may change its point of attachment to the Internet. The mobile network is operated by a basic specification to support network mobility called Network Mobility (NEMO) Basic Support. However, NEMO basic Support mechanism has some problem in continuous communication. In this paper, we propose robust and cost-efficient algorithm. And we simulate proposed method and conclude some remarks.

  8. Speech coding at 4800 bps for mobile satellite communications

    NASA Technical Reports Server (NTRS)

    Gersho, Allen; Chan, Wai-Yip; Davidson, Grant; Chen, Juin-Hwey; Yong, Mei

    1988-01-01

    A speech compression project has recently been completed to develop a speech coding algorithm suitable for operation in a mobile satellite environment aimed at providing telephone quality natural speech at 4.8 kbps. The work has resulted in two alternative techniques which achieve reasonably good communications quality at 4.8 kbps while tolerating vehicle noise and rather severe channel impairments. The algorithms are embodied in a compact self-contained prototype consisting of two AT and T 32-bit floating-point DSP32 digital signal processors (DSP). A Motorola 68HC11 microcomputer chip serves as the board controller and interface handler. On a wirewrapped card, the prototype's circuit footprint amounts to only 200 sq cm, and consumes about 9 watts of power.

  9. Considerations of digital phase modulation for narrowband satellite mobile communication

    NASA Technical Reports Server (NTRS)

    Grythe, Knut

    1990-01-01

    The Inmarsat-M system for mobile satellite communication is specified as a frequency division multiple access (FDMA) system, applying Offset Quadrature Phase Shift Keying (QPSK) for transmitting 8 kbit/sec in 10 kHz user channel bandwidth. We consider Digital Phase Modulation (DPM) as an alternative modulation format for INMARSAT-M. DPM is similar to Continuous Phase Modulation (CPM) except that DPM has a finite memory in the premodular filter with a continuous varying modulation index. It is shown that DPM with 64 states in the VA obtains a lower bit error rate (BER). Results for a 5 kHz system, with the same 8 kbit/sec transmitted bitstream, is also presented.

  10. Isolated and coupled superquadric loop antennas for mobile communications applications

    NASA Technical Reports Server (NTRS)

    Jensen, Michael A.; Rahmat-Samii, Yahya

    1993-01-01

    This work provides an investigation of the performance of loop antennas for use in mobile communications applications. The analysis tools developed allow for high flexibility by representing the loop antenna as a superquadric curve, which includes the case of circular, elliptical, and rectangular loops. The antenna may be in an isolated environment, located above an infinite ground plane, or placed near a finite conducting plate or box. In cases where coupled loops are used, the two loops may have arbitrary relative positions and orientations. Several design examples are included to illustrate the versatility of the analysis capabilities. The performance of coupled loops arranged in a diversity scheme is also evaluated, and it is found that high diversity gain can be achieved even when the antennas are closely spaced.

  11. Plan of advanced satellite communications experiment using ETS-VI

    NASA Technical Reports Server (NTRS)

    Shiomi, Tadashi

    1988-01-01

    Communications Research Laboratory (CRL, Ministry of Posts and Telecommunications, Japan) has been engaged in development of three advanced satellite communication payloads aiming at experiments by Japan's 2-ton class Engineering Test Satellite VI (ETS-VI) which is to be launched in H-II rocket by NASDA in August 1992. CRL's three experimental systems are: (1) S-band inter-satellite communications; (2) millimeter-wave inter-satellite and personal-satellite communications; and (3) optical inter-satellite communications. CRL develops experimental optical communication system with telescope of 75 mm diameter which has gimbal mirror beam pointing/tracking mechanism. The onboard system has fundamental optical communication functions with laser diode transmitter of wavelength 0.83 micron, laser beam point-ahead mechanism, receiver of wavelength 0.51 micron, modulation/demodulation subsystem, and so on.

  12. Adaptive beamforming in a CDMA mobile satellite communications system

    NASA Technical Reports Server (NTRS)

    Munoz-Garcia, Samuel G.

    1993-01-01

    Code-Division Multiple-Access (CDMA) stands out as a strong contender for the choice of multiple access scheme in these future mobile communication systems. This is due to a variety of reasons such as the excellent performance in multipath environments, high scope for frequency reuse and graceful degradation near saturation. However, the capacity of CDMA is limited by the self-interference between the transmissions of the different users in the network. Moreover, the disparity between the received power levels gives rise to the near-far problem, this is, weak signals are severely degraded by the transmissions from other users. In this paper, the use of time-reference adaptive digital beamforming on board the satellite is proposed as a means to overcome the problems associated with CDMA. This technique enables a high number of independently steered beams to be generated from a single phased array antenna, which automatically track the desired user signal and null the unwanted interference sources. Since CDMA is interference limited, the interference protection provided by the antenna converts directly and linearly into an increase in capacity. Furthermore, the proposed concept allows the near-far effect to be mitigated without requiring a tight coordination of the users in terms of power control. A payload architecture will be presented that illustrates the practical implementation of this concept. This digital payload architecture shows that with the advent of high performance CMOS digital processing, the on-board implementation of complex DSP techniques -in particular digital beamforming- has become possible, being most attractive for Mobile Satellite Communications.

  13. Advanced Communication Technology Satellite (ACTS) multibeam antenna technology verification experiments

    NASA Technical Reports Server (NTRS)

    Acosta, Roberto J.; Larko, Jeffrey M.; Lagin, Alan R.

    1992-01-01

    The Advanced Communication Technology Satellite (ACTS) is a key to reaching NASA's goal of developing high-risk, advanced communications technology using multiple frequency bands to support the nation's future communication needs. Using the multiple, dynamic hopping spot beams, and advanced on board switching and processing systems, ACTS will open a new era in communications satellite technology. One of the key technologies to be validated as part of the ACTS program is the multibeam antenna with rapidly reconfigurable hopping and fixed spot beam to serve users equipped with small-aperature terminals within the coverage areas. The proposed antenna technology experiments are designed to evaluate in-orbit ACTS multibeam antenna performance (radiation pattern, gain, cross pol levels, etc.).

  14. MMIC technology for advanced space communications systems

    NASA Technical Reports Server (NTRS)

    Downey, A. N.; Connolly, D. J.; Anzic, G.

    1984-01-01

    The current NASA program for 20 and 30 GHz monolithic microwave integrated circuit (MMIC) technology is reviewed. The advantages of MMIC are discussed. Millimeter wavelength MMIC applications and technology for communications systems are discussed. Passive and active MMIC compatible components for millimeter wavelength applications are investigated. The cost of a millimeter wavelength MMIC's is projected.

  15. Advances and prospects in visible light communications

    NASA Astrophysics Data System (ADS)

    Hongda, Chen; Chunhui, Wu; Honglei, Li; Xiongbin, Chen; Zongyu, Gao; Shigang, Cui; Qin, Wang

    2016-01-01

    Visible light communication (VLC) is an emerging technology in optical wireless communication (OWC) that has attracted worldwide research in recent years. VLC can combine communication and illumination together, which could be applied in many application scenarios such as visible light communication local area networks (VLANs), indoor localization, and intelligent lighting. In recent years, pioneering and significant work have been made in the field of VLC. In this paper, an overview of the recent progress in VLC is presented. We also demonstrate our recent experiment results including bidirectional 100 Mbit/s VLAN or Li-Fi system based on OOK modulation without blue filter. The VLC systems that we proposed are good solutions for high-speed VLC application systems with low-cost and low-complexity. VLC technology shows a bright future due to its inherent advantages, shortage of RF spectra and ever increasing popularity of white LEDs. Project supported by the National High Technology Research and Development Program of China (Nos. 2015AA033303, 2013AA013602, 2013AA013603, 2013AA03A104), the National Natural Science Foundation of China (Nos. 61178051, 61321063, 61335010, 61178048, 61275169), and the National Basic Research Program of China (Nos. 2013CB329205, 2011CBA00608).

  16. The Advanced Communications Technology Satellite (ACTS) capabilities for serving science

    NASA Technical Reports Server (NTRS)

    Meyer, Thomas R.

    1990-01-01

    Results of research on potential science applications of the NASA Advanced Communications Technology Satellite (ACTS) are presented. Discussed here are: (1) general research on communications related issues; (2) a survey of science-related activities and programs in the local area; (3) interviews of selected scientists and associated telecommunications support personnel whose projects have communications requirements; (4) analysis of linkages between ACTS functionality and science user communications activities and modes of operation; and (5) an analysis of survey results and the projection of conclusions to a national scale.

  17. Technological Developments and Socio-Economic Issues of Wireless Mobile Communications.

    ERIC Educational Resources Information Center

    Beaubrun, Ronald; Pierre, Samuel

    2001-01-01

    Examines technological developments and the worldwide social-economic impacts of wireless mobile communications. Provides an overview of the technological developments of wireless mobile communications. Describes the evolution towards next-generation systems. Analyzes reasons for the growth rate of subscribers and the related social development.…

  18. 78 FR 34132 - Certain Portable Electronic Communications Devices, Including Mobile Phones and Components...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-06-06

    ... COMMISSION Certain Portable Electronic Communications Devices, Including Mobile Phones and Components Thereof... published a notice (78 FR 12892, May 31, 2013) of receipt of complaint entitled Certain Portable Electronic Communications Devices, Including Mobile Phones and Components Thereof, DN 2958; the Commission...

  19. Underground communications and tracking technology advances

    SciTech Connect

    Fiscor, S.

    2007-03-15

    As the June 2009 deadline set by the MINER Act grows near, several technologies have emerged as possible options for communicating and tracking underground coal miners in the event of an emergency or disaster. NIOSH is currently deciding how best to invest $10 million assigned by Congress under an Emergency Supplementary Appropriations Act (ESA) to research and develop mine safety technology. Medium and ultra high frequency (UHF) systems seem to be leading the pack with radio frequency identification (RFID) tags serving as the tracking system. Wireless mesh systems can serve as a communications infrastructure and they can do much more. Even more technologies continue to emerge, such as inertial navigation tracking systems. Mines are discovering the wonders of modern voice and data communications underground. Still no one know if it is economically practical to design a system that will function after a coal mine explosion. From the nineteen systems submitted to MSHA's request for information (RFI), six systems were selected that represented most of the technologies that had been proposed: the Rajant Breadcrumb, Innovative Wireless, Concurrent Technologies/Time Domain, Transtek, Gamma Services, and the Kutta Consulting systems. They were tested at CONSOL Energy's McElroy mine in April 2006. MSHA felt that all of those systems needed a significant amount of work before they were ready for use in a underground coal mining environment. The agency continues to work with these, and other manufacturers, to assist in arranging for field demonstration and then to gain MSHA approval.

  20. An overview of the OmniTRACS: The first operational mobile Ku-band satellite communications

    NASA Technical Reports Server (NTRS)

    Salmasi, Allen

    1988-01-01

    The service features of the OmniTRACS system developed by Omninet Communications Services of Los Angeles, California are described. This system is the first operational mobile Ku-band satellite communications system that provides two-way messaging and position determination and reporting services to mobile users on a nationwide basis. The system uses existing Ku-band satellites under a secondary international allocation for mobile satellite services.

  1. Consistent low-field mobility modeling for advanced MOS devices

    NASA Astrophysics Data System (ADS)

    Stanojević, Zlatan; Baumgartner, Oskar; Filipović, Lidija; Kosina, Hans; Karner, Markus; Kernstock, Christian; Prause, Philipp

    2015-10-01

    In this paper we develop several extensions to semi-classical modeling of low-field mobility, which are necessary to treat planar and non-planar channel geometries on equal footing. We advance the state-of-the-art by generalizing the Prange-Nee model for surface roughness scattering to non-planar geometries, providing a fully numerical treatment of Coulomb scattering, and formulating the Kubo-Greenwood mobility model in a consistent, dimension-independent manner. These extensions allow meaningful comparison of planar and non-planar structures alike, and open the door to evaluating emerging device concepts, such as the FinFET or the junction-less transistor, on physical grounds.

  2. Performance Evaluation of Mobile Ad Hoc Network Based Communications for Future Mobile Tele-Emergency System

    NASA Astrophysics Data System (ADS)

    Viswacheda, D. V.; Barukang, L.; Hamid, M. Y.; Arifianto, M. S.

    Sparked by awareness of the limitations to provide medical services in remote areas, researchers have perceived that developing telemedicine systems is inevitable. In most cases very remote areas and disaster struck areas lack telecommunication infrastructure. Telemedicine system operating in such areas must have advanced wireless technology supporting it in devastating situation, hence it is called as tele-emergency system. Our approach is on MANET combined with Mobile IP and MIPV6, is the basis of infrastructure for the mobile tele-emergency system. The tele-emergency system requires data, voice and video transmission in its network. In this investigation, evaluation is based on simulation of the various ITU-T standard CODECs of VoIP and video transmission over MANET using discrete event simulator NS-2. The results of simulation showed that ITU-T G723.1 worked well in the MANET environment than the other CODECs for VoIP in fixed and mobility tele-emergency environments. From the simulation of video CODEC performance evaluation, it was observed that H.263 performed to a great extent in random small scale environment and also in multiple video flow of 57.6kbps speed video transmission.

  3. Advanced Sensors Boost Optical Communication, Imaging

    NASA Technical Reports Server (NTRS)

    2009-01-01

    Brooklyn, New York-based Amplification Technologies Inc. (ATI), employed Phase I and II SBIR funding from NASA s Jet Propulsion Laboratory to forward the company's solid-state photomultiplier technology. Under the SBIR, ATI developed a small, energy-efficient, extremely high-gain sensor capable of detecting light down to single photons in the near infrared wavelength range. The company has commercialized this technology in the form of its NIRDAPD photomultiplier, ideal for use in free space optical communications, lidar and ladar, night vision goggles, and other light sensing applications.

  4. Using satellite communications for a mobile computer network

    NASA Technical Reports Server (NTRS)

    Wyman, Douglas J.

    1993-01-01

    The topics discussed include the following: patrol car automation, mobile computer network, network requirements, network design overview, MCN mobile network software, MCN hub operation, mobile satellite software, hub satellite software, the benefits of patrol car automation, the benefits of satellite mobile computing, and national law enforcement satellite.

  5. Adaptive digital beamforming for a CDMA mobile communications payload

    NASA Technical Reports Server (NTRS)

    Munoz-Garcia, Samuel G.; Ruiz, Javier Benedicto

    1993-01-01

    In recent years, Spread-Spectrum Code Division Multiple Access (CDMA) has become a very popular access scheme for mobile communications due to a variety of reasons: excellent performance in multipath environments, high scope for frequency reuse, graceful degradation near saturation, etc. In this way, a CDMA system can support simultaneous digital communication among a large community of relatively uncoordinated users sharing a given frequency band. Nevertheless, there are also important problems associated with the use of CDMA. First, in a conventional CDMA scheme, the signature sequences of asynchronous users are not orthogonal and, as the number of active users increases, the self-noise generated by the mutual interference between users considerably degrades the performance, particularly in the return link. Furthermore, when there is a large disparity in received powers - due to differences in slant range or atmospheric attenuation - the non-zero cross-correlation between the signals gives rise to the so-called near-far problem. This leads to an inefficient utilization of the satellite resources and, consequently, to a drastic reduction in capacity. Several techniques were proposed to overcome this problem, such as Synchronized CDMA - in which the signature sequences of the different users are quasi-orthogonal - and power control. At the expense of increased network complexity and user coordination, these techniques enable the system capacity to be restored by equitably sharing the satellite resources among the users. An alternative solution is presented based upon the use of time-reference adaptive digital beamforming on board the satellite. This technique enables a high number of independently steered beams to be generated from a single phased array antenna, which automatically track the desired user signal and null the unwanted interference source. In order to use a time-reference adaptive antenna in a communications system, the main challenge is to obtain a

  6. Advanced integrated WDM system for POF communication

    NASA Astrophysics Data System (ADS)

    Haupt, M.; Fischer, U. H. P.

    2009-01-01

    Polymer Optical Fibres (POFs) show clear advantages compared to copper and glass fibres. In essence, POFs are inexpensive, space-saving and not susceptible to electromagnetic interference. Thus, the usage of POFs have become a reasonable alternative in short distance data communication. Today, POFs are applied in a wide number of applications due to these specific advantages. These applications include automotive communication systems and in-house-networks. State-of-the-art is to transmit data with only one channel over POF, this limits the bandwidth. To solve this problem, an integrated MUX/DEMUX-element for WDM over POF is designed and developed to use multiple channels. This integration leads to low costs, therefore this component is suitable for mass market applications. The fundamental idea is to separate the chromatic parts of the light in its monochromatic components by means of a grating based on an aspheric mirror. Due to the high NA of the POF the setup has to be designed in a 3D-approach. Therefore this setup cannot be compared with the planar solutions available on market, they would result high losses in the 3rd dimension. To achieve a fast and optimized design an optical simulation program is used. Particular attention has to be paid to the design of the POF as a light source in the simulation program and the optimisation of the grating. The following realization of the demultiplexer is planed to be done with injection molding. This technology offers easy and very economical processing. These advantages make this technology first choice for optical components in the low-cost array.

  7. Advanced communications, tracking, robotic vision technology for space applications

    NASA Technical Reports Server (NTRS)

    Krishen, Kumar

    1987-01-01

    Recent advancements in the areas of tracking, communications, and robotics vision sensors being pursued within NASA, as applicable to space programs, are presented. Optical and laser-based communications and tracking systems and applications to space programs are discussed. Communication systems for multiple access, broadband, high data rate, and efficient operations are given. Current efforts at 20/30 GHz and millimeter wave bands are summarized. The use of optical data processing in control system applications for rendezvous and docking is presented. Robotics vision, based on television, laser, and microwave sensors for space applications, is discussed. The fusion of these technologies for remote control, station keeping, tracking, inspection, and satellite repair is detailed.

  8. Directedness of Information Flow in Mobile Phone Communication Networks

    PubMed Central

    Peruani, Fernando; Tabourier, Lionel

    2011-01-01

    Without having direct access to the information that is being exchanged, traces of information flow can be obtained by looking at temporal sequences of user interactions. These sequences can be represented as causality trees whose statistics result from a complex interplay between the topology of the underlying (social) network and the time correlations among the communications. Here, we study causality trees in mobile-phone data, which can be represented as a dynamical directed network. This representation of the data reveals the existence of super-spreaders and super-receivers. We show that the tree statistics, respectively the information spreading process, are extremely sensitive to the in-out degree correlation exhibited by the users. We also learn that a given information, e.g., a rumor, would require users to retransmit it for more than 30 hours in order to cover a macroscopic fraction of the system. Our analysis indicates that topological node-node correlations of the underlying social network, while allowing the existence of information loops, they also promote information spreading. Temporal correlations, and therefore causality effects, are only visible as local phenomena and during short time scales. Consequently, the very idea that there is (intentional) information spreading beyond a small vecinity is called into question. These results are obtained through a combination of theory and data analysis techniques. PMID:22216128

  9. David Florida Laboratory: Support for mobile satellite communications

    NASA Technical Reports Server (NTRS)

    Dumoulin, Jean-Guy; Mamen, Rolf

    1995-01-01

    The comprehensive integration and environmental (including RF) test facilities of the Canadian Space Agency's David Florida Laboratory (CSA)(DFL) were used extensively for the MSAT Program. Following a description of the facilities, the paper outlines their application to the qualification of the two MSAT satellites following an overview of the test plan. Particular emphasis is given to passive intermodulation measurement (PIM) demands, which for the MSAT satellites, contributed to the need to extend the anechoic chamber. The extended chamber was also used for an EMC test and SAR signature test of the RADARSAT satellite. The DFL's facilities are being used for additional aspects of mobile satellite communications. One shielded anechoic Extra High Frequency (EHF) chamber and associated test equipment are employed predominantly for measuring the performance of the IRIDIUM satellites' Engineering Model Gateway Moveable Antennas (EM)(GMA). Other chambers are used for testing aeronautical antennas on behalf of Inmarsat. Still others combine thermal and PIM testing. The paper concludes with a review of the test requirements of evolving satcom missions such as Inmarsat Aero-1.

  10. Robotic Communication Terminals as a Mobility Support System for Elderly and Disabled People(2)

    NASA Astrophysics Data System (ADS)

    Yairi, Ikuko Eguchi; Igi, Seiji

    We have been developing Robotic Communication Terminals (RCT) as a mobility support system for the elderly and disabled people, which assists for their impaired elements of mobility— recognition, actuation, and information access. The RCT consist of three types of terminals: “environment-embedded terminal”“user-carried mobile terminal”, and “user-carrying mobile terminal”. These terminals communicate with one another to provide the users with a comfortable means of mobility. In this paper, we introduce the overview of our research. The recent progress is also presented as well as the future plan.

  11. New Opportunities with the Advanced Communications Technology Satellite (ACTS)

    NASA Technical Reports Server (NTRS)

    Bauer, Robert

    1998-01-01

    Various issues associated with the Advanced Communications Technology Satellite (ACTS) are presented in viewgraph form. Specific topics include: 1) ACTS program review; 2) Spot beam locations; 3) Key ACTS technologies; 4) ACTS accomplishments; 5) Experiments operations; 6) Inclined orbit opportunity, mission and impact; 7) Modifications summary; 8) Experiment opportunity, categories, processes; and 9) Recent and ongoing activity.

  12. Interoperability framework for communication between processes running on different mobile operating systems

    NASA Astrophysics Data System (ADS)

    Gal, A.; Filip, I.; Dragan, F.

    2016-02-01

    As we live in an era where mobile communication is everywhere around us, the necessity to communicate between the variety of the devices we have available becomes even more of an urge. The major impediment to be able to achieve communication between the available devices is the incompatibility between the operating systems running on these devices. In the present paper we propose a framework that will make possible the ability to inter-operate between processes running on different mobile operating systems. The interoperability process will make use of any communication environment which is made available by the mobile devices where the processes are installed. The communication environment is chosen so as the process is optimal in terms of transferring the data between the mobile devices. The paper defines the architecture of the framework, expanding the functionality and interrelation between modules that make up the framework. For the proof of concept, we propose to use three different mobile operating systems installed on three different types of mobile devices. Depending on the various factors related to the structure of the mobile devices and the data type to be transferred, the framework will establish a data transfer protocol that will be used. The framework automates the interoperability process, user intervention being limited to a simple selection from the options that the framework suggests based on the full analysis of structural and functional elements of the mobile devices used in the process.

  13. Big Data Analytics for Disaster Preparedness and Response of Mobile Communication Infrastructure during Natural Hazards

    NASA Astrophysics Data System (ADS)

    Zhong, L.; Takano, K.; Ji, Y.; Yamada, S.

    2015-12-01

    The disruption of telecommunications is one of the most critical disasters during natural hazards. As the rapid expanding of mobile communications, the mobile communication infrastructure plays a very fundamental role in the disaster response and recovery activities. For this reason, its disruption will lead to loss of life and property, due to information delays and errors. Therefore, disaster preparedness and response of mobile communication infrastructure itself is quite important. In many cases of experienced disasters, the disruption of mobile communication networks is usually caused by the network congestion and afterward long-term power outage. In order to reduce this disruption, the knowledge of communication demands during disasters is necessary. And big data analytics will provide a very promising way to predict the communication demands by analyzing the big amount of operational data of mobile users in a large-scale mobile network. Under the US-Japan collaborative project on 'Big Data and Disaster Research (BDD)' supported by the Japan Science and Technology Agency (JST) and National Science Foundation (NSF), we are going to investigate the application of big data techniques in the disaster preparedness and response of mobile communication infrastructure. Specifically, in this research, we have considered to exploit the big amount of operational information of mobile users for predicting the communications needs in different time and locations. By incorporating with other data such as shake distribution of an estimated major earthquake and the power outage map, we are able to provide the prediction information of stranded people who are difficult to confirm safety or ask for help due to network disruption. In addition, this result could further facilitate the network operators to assess the vulnerability of their infrastructure and make suitable decision for the disaster preparedness and response. In this presentation, we are going to introduce the

  14. Coded multicarrier 16 QAM system for land mobile communications

    NASA Astrophysics Data System (ADS)

    Sasaoka, Hideichi; Omori, Youko

    1995-06-01

    This paper studies a coded multicarrier 16 QAM system for land mobile communications and proposed methods for improving quality and bit-rate and spectral efficiency. The proposed system uses a symbol-timing adjustment method in addition to a multicarrier transmission scheme to provide immunity against frequency-selective fading distortion which becomes more severe for high bit-rate transmission. The system uses pilot-symbol aided 16 QAM to increase spectral efficiency. It also uses methods of symbol allocation to carriers and symbol interleaving, in addition to Reed-Solomon coding with maximum likelihood decoding, to increase the bit error rate (BER) performance. Space diversity method, with maximum ratio combining, can be used to further improve the BER performance. A computer simulation of the proposed system is carried out with a bandwidth of 200 kHz and a total information rate of 256 kbit/s. The simulation results show that the proposed system provides immunity against frequency-selective fading and that space diversity further improves this. A BER of less than 10(exp -4) is obtained at a E(sub b)/N(sub 0) of 30 dB and a delay spread of 3.4 microsecs in the case of non-diversity. A BER of less 10(exp -4) is also obtained at a E(sub b)/N(sub 0) of 15 dB and a delay spread of 5.5 microsecs in the case of diversity. These results confirm that the proposed system can achieve high quality and high bit-rate transmission with high spectral efficiency.

  15. IMT-2000 Satellite Standards with Applications to Mobile Air Traffic Communications Networks

    NASA Technical Reports Server (NTRS)

    Shamma, Mohammed A.

    2004-01-01

    The International Mobile Telecommunications - 2000 (IMT-2000) standard and more specifically the Satellite component of it, is investigated as a potential alternative for communications to aircraft mobile users en-route and in terminal area. Its application to Air Traffic Management (ATM) communication needs is considered. A summary of the specifications of IMT-2000 satellite standards are outlined. It is shown via a system research analysis that it is possible to support most air traffic communication needs via an IMT-2000 infrastructure. This technology can compliment existing, or future digital aeronautical communications technologies such as VDL2, VDL3, Mode S, and UAT.

  16. Advanced Communication and Networking Technologies for Mars Exploration

    NASA Technical Reports Server (NTRS)

    Bhasin, Kul; Hayden, Jeff; Agre, Jonathan R.; Clare, Loren P.; Yan, Tsun-Yee

    2001-01-01

    Next-generation Mars communications networks will provide communications and navigation services to a wide variety of Mars science vehicles including: spacecraft that are arriving at Mars, spacecraft that are entering and descending in the Mars atmosphere, scientific orbiter spacecraft, spacecraft that return Mars samples to Earth, landers, rovers, aerobots, airplanes, and sensing pods. In the current architecture plans, the communication services will be provided using capabilities deployed on the science vehicles as well as dedicated communication satellites that will together make up the Mars network. This network will evolve as additional vehicles arrive, depart or end their useful missions. Cost savings and increased reliability will result from the ability to share communication services between missions. This paper discusses the basic architecture that is needed to support the Mars Communications Network part of NASA's Space Science Enterprise (SSE) communications architecture. The network may use various networking technologies such as those employed in the terrestrial Internet, as well as special purpose deep-space protocols to move data and commands autonomously between vehicles, at disparate Mars vicinity sites (on the surface or in near-Mars space) and between Mars vehicles and earthbound users. The architecture of the spacecraft on-board local communications is being reconsidered in light of these new networking requirements. The trend towards increasingly autonomous operation of the spacecraft is aimed at reducing the dependence on resource scheduling provided by Earth-based operators and increasing system fault tolerance. However, these benefits will result in increased communication and software development requirements. As a result, the envisioned Mars communications infrastructure requires both hardware and protocol technology advancements. This paper will describe a number of the critical technology needs and some of the ongoing research

  17. Activities of the European Conference of Posts and Telecommunications (CEPT) special Group on Mobile Communications (GSM)

    NASA Astrophysics Data System (ADS)

    Dupuis, P.

    1986-09-01

    The group on mobile communications (GSM) of the European Conference of Posts and Telecommunications is in charge of specifying a harmonized mobile radio communication system adapted to the needs and to the technological environment of the coming decades. The means at the disposal of GSM, the objectives of the system, (basic requirements), the program, and time schedule are presented. The strength of GSM and the dangers which it must avoid are pointed out.

  18. Evolution of Implicit and Explicit Communication in Mobile Robots

    NASA Astrophysics Data System (ADS)

    de Greeff, Joachim; Nolfi, Stefano

    This work investigates the conditions in which a population of embodied agents evolved for the ability to display coordinated/cooperative skills can develop an ability to communicate, whether and to what extent the evolved communication system can complexify during the course of the evolutionary process, and how the characteristics of such communication system varies evolutionarily. The analysis of the obtained results indicates that evolving robots develop a capacity to access/generate information which has a communicative value, an ability to produce different signals encoding useful regularities, and an ability to react appropriately to explicit and implicit signals. The analysis of the obtained results allows us to formulate detailed hypothesis on the evolution of communication for what concern aspects such us: (i) how communication can emerge from a population of initially non-communicating agents, (ii) how communication systems can complexify, (iii) how signals/meanings can originate and how they can be grounded in agents' sensory-motor states.

  19. Distress detection, location, and communications using advanced space technology

    NASA Technical Reports Server (NTRS)

    Sivertson, W. E., Jr.

    1977-01-01

    This paper briefly introduces a concept for low-cost, global, day-night, all-weather disaster warning and assistance. Evolving, advanced space technology with passive radio frequency reflectors in conjunction with an imaging synthetic aperture radar is employed to detect, identify, locate, and provide passive communication with earth users in distress. This concept evolved from a broad NASA research on new global search and rescue techniques. Appropriate airborne radar test results from this research are reviewed and related to potential disaster applications. The analysis indicates the approach has promise for disaster communications relative to floods, droughts, earthquakes, volcanic eruptions, and severe storms.

  20. Scaling of data communications for an advanced supercomputer network

    NASA Technical Reports Server (NTRS)

    Levin, E.; Eaton, C. K.; Young, Bruce

    1986-01-01

    The goal of NASA's Numerical Aerodynamic Simulation (NAS) Program is to provide a powerful computational environment for advanced research and development in aeronautics and related disciplines. The present NAS system consists of a Cray 2 supercomputer connected by a data network to a large mass storage system, to sophisticated local graphics workstations and by remote communication to researchers throughout the United States. The program plan is to continue acquiring the most powerful supercomputers as they become available. The implications of a projected 20-fold increase in processing power on the data communications requirements are described.

  1. Sales Communications in a Mobile World: Using the Latest Technology and Retaining the Personal Touch

    ERIC Educational Resources Information Center

    Norris, Daniel T.

    2007-01-01

    Salespeople increasingly have the opportunity to use technology to more quickly communicate with a larger number of clients and customers. Mobile technology, in particular, gives salespeople many advantages in rapidly reaching a large customer base. Furthermore, customers are increasingly employing mobile technology, making them increasingly…

  2. Phased Arrays of Ground and Airborne Mobile Terminals for Satellite Communications

    NASA Technical Reports Server (NTRS)

    Huang, John

    1996-01-01

    Phased array antenna is beginning to play an important in the arena of mobile/satellite communications. Two examples of mobile terminal phased arrays will be shown. Their technical background, challenges, and cost drivers will be discussed. A possible solution to combat some of the deficiencies of the conventional phased array by exploiting the phased reflectarray technology will be briefly presented.

  3. The design of a linear L-band high power amplifier for mobile communication satellites

    NASA Technical Reports Server (NTRS)

    Whittaker, N.; Brassard, G.; Li, E.; Goux, P.

    1990-01-01

    A linear L-band solid state high power amplifier designed for the space segment of the Mobile Satellite (MSAT) mobile communication system is described. The amplifier is capable of producing 35 watts of RF power with multitone signal at an efficiency of 25 percent and with intermodulation products better than 16 dB below carrier.

  4. Laser Communication Demonstration System (LSCS) and Future Mobile Satellite Services

    NASA Technical Reports Server (NTRS)

    Chen, C. -C.; Lesh, J. R.

    1995-01-01

    The Laser Communications Demonstration System (LCDS) is a proposed in-orbit demonstration of high data rate laser communications technology conceived jointly by NASA and U.S. industry. The program objectives are to stimulate industry development and to demonstrate the readiness of high data rate optical communications in Earth Orbit. For future global satellite communication systems using intersatellite links (ISLs), laser communications technology can offer reduced mass , reduced power requirements, and increased channel bandwidths without regulatory restraint. This paper provides comparisons with radio systems and status of the program.

  5. 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%.

  6. Display-based communications for advanced transport aircraft

    NASA Technical Reports Server (NTRS)

    Lee, Alfred T.

    1989-01-01

    The next generation of civil transport aircraft will depend increasingly upon ground-air-ground and satellite data link for information critical to safe and efficient air transportation. Previous studies which examined the concept of display-based communications in addition to, or in lieu of, conventional voice transmissions are reviewed. A full-mission flight simulation comparing voice and display-based communication modes in an advanced transport aircraft is also described. The results indicate that a display-based mode of information transfer does not result in significantly increased aircrew workload, but does result in substantially increased message acknowledgment times when compared to conventional voice transmissions. User acceptance of the display-based communication system was generally high, replicating the findings of previous studies. However, most pilots tested expressed concern over the potential loss of information available from frequency monitoring which might result from the introduction of discrete address communications. Concern was expressed by some pilots for the reduced time available to search for conflicting traffic when using the communications display system. The implications of the findings for the design of display-based communications are discussed.

  7. Concept for advanced satellite communications and required technologies

    NASA Technical Reports Server (NTRS)

    Ramler, J. R.; Salzman, J. A.

    1982-01-01

    The advanced communications technology satellite (ACTS) program of NASA is aimed at the development of high risk technologies that will enable exploiting higher frequency bands and techniques for improving frequency reuse. The technologies under development include multiple beam spacecraft antennas, on-board switching and processing, RF devices and components and advanced earth stations. The program focus is on the Ka-band (30/20 GHz) as the implementing frequency since it has five times the bandwidth of either the C- or Ku-bands. However, the technology being developed is applicable to other frequency bands as well and will support a wide range of future communications systems required by NASA, other Government agencies and the commercial sector. An overview is presented of an operational 30/20 GHz satellite system that may evolve. How the system addresses service requirements is discussed, and the technology required and being developed is considered. Previously announced in STAR as N83-11210

  8. Concept for advanced satellite communications and required technologies

    NASA Technical Reports Server (NTRS)

    Ramler, J. R.; Salzman, J. A.

    1982-01-01

    The advanced communications technology satellite (ACTS) program of NASA is aimed at the development of high risk technologies that will enable exploiting higher frequency bands and techniques for improving frequency reuse. The technologies under development include multiple beam spacecraft antennas, on-board switching and processing, RF devices and components and advanced Earth stations. The program focus is on the Ka-band (30/20 GHz) as the implementing frequency since it has five times the bandwidth of either the C- or Ku-bands. However, the technology being developed is applicable to other frequency bands as well and will support a wide range of future communications systems required by NASA, other Government agencies and the commercial sector. An overview is presented of an operational 30/20 GHz satellite system that may evolve. How the system addresses service requirements is discussed, and the technology required and being developed is considered.

  9. Attitude Control Subsystem for the Advanced Communications Technology Satellite

    NASA Technical Reports Server (NTRS)

    Hewston, Alan W.; Mitchell, Kent A.; Sawicki, Jerzy T.

    1996-01-01

    This paper provides an overview of the on-orbit operation of the Attitude Control Subsystem (ACS) for the Advanced Communications Technology Satellite (ACTS). The three ACTS control axes are defined, including the means for sensing attitude and determining the pointing errors. The desired pointing requirements for various modes of control as well as the disturbance torques that oppose the control are identified. Finally, the hardware actuators and control loops utilized to reduce the attitude error are described.

  10. Advanced technology for space communications and tracking systems

    NASA Technical Reports Server (NTRS)

    Krishen, Kumar

    1988-01-01

    Technological advances in the communications and tracking areas being developed by NASA and applicable to future missions and associated space operations are discussed. The applications scenarios considered include the Space Shuttle, Space Station, lunar base, and Mars missions. Performance goals and conceptual designs are discussed, and the relevance of optical, laser, and millimeter wave-based implementations to the various applications are examined. Recommendations for future systems developments are addressed.

  11. Monolithic microwave integrated circuit technology for advanced space communication

    NASA Technical Reports Server (NTRS)

    Ponchak, George E.; Romanofsky, Robert R.

    1988-01-01

    Future Space Communications subsystems will utilize GaAs Monolithic Microwave Integrated Circuits (MMIC's) to reduce volume, weight, and cost and to enhance system reliability. Recent advances in GaAs MMIC technology have led to high-performance devices which show promise for insertion into these next generation systems. The status and development of a number of these devices operating from Ku through Ka band will be discussed along with anticipated potential applications.

  12. Advanced Communications Technology Satellite (ACTS): Four-Year System Performance

    NASA Technical Reports Server (NTRS)

    Acosta, Roberto J.; Bauer, Robert; Krawczyk, Richard J.; Reinhart, Richard C.; Zernic, Michael J.; Gargione, Frank

    1999-01-01

    The Advanced Communications Technology Satellite (ACTS) was conceived at the National Aeronautics and Space Administration (NASA) in the late 1970's as a follow-on program to ATS and CTS to continue NASA's long history of satellite communications projects. The ACTS project set the stage for the C-band satellites that started the industry, and later the ACTS project established the use of Ku-band for video distribution and direct-to-home broadcasting. ACTS, launched in September 1993 from the space shuttle, created a revolution in satellite system architecture by using digital communications techniques employing key technologies such as a fast hopping multibeam antenna, an on-board baseband processor, a wide-band microwave switch matrix, adaptive rain fade compensation, and the use of 900 MHz transponders operating at Ka-band frequencies. This paper describes the lessons learned in each of the key ACTS technology areas, as well as in the propagation investigations.

  13. Using Mobile Communication Technology in High School Education: Motivation, Pressure, and Learning Performance

    ERIC Educational Resources Information Center

    Rau, Pei-Luen Patrick; Gao, Qin; Wu, Li-Mei

    2008-01-01

    Motivation and pressure are considered two factors impacting vocational senior high school student learning. New communication technology, especially mobile communication technology, is supposed to be effective in encouraging interaction between the student and the instructor and improving learning efficiency. Social presence and information…

  14. 77 FR 28797 - Redundancy of Communications Systems: Backup Power Private Land Mobile Radio Services: Selection...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-05-16

    ... From the Federal Register Online via the Government Publishing Office FEDERAL COMMUNICATIONS COMMISSION 47 CFR Parts 12 and 90 Redundancy of Communications Systems: Backup Power Private Land Mobile Radio Services: Selection and Assignment of Frequencies, and Transition of the Upper 200 Channels in...

  15. Satellite-aided land mobile communications system implementation considerations

    NASA Technical Reports Server (NTRS)

    Leroy, B. E.

    1982-01-01

    It was proposed that a satellite-based land mobile radio system could effectively extend the terrestrial cellular mobile system into rural and remote areas. The market, technical and economic feasibility for such a system is studied. Some of the aspects of implementing an operational mobile-satellite system are discussed. In particular, two key factors in implementation are examined: (1) bandwidth requirements; and (2) frequency sharing. Bandwidth requirements are derived based on the satellite antenna requirements, modulation characteristics and numbers of subscribers. Design trade-offs for the satellite system and potential implementation scenarios are identified. Frequency sharing is examined from a power flux density and modulation viewpoint.

  16. Recovery Act: Advanced Direct Methanol Fuel Cell for Mobile Computing

    SciTech Connect

    Fletcher, James H.; Cox, Philip; Harrington, William J; Campbell, Joseph L

    2013-09-03

    ABSTRACT Project Title: Recovery Act: Advanced Direct Methanol Fuel Cell for Mobile Computing PROJECT OBJECTIVE The objective of the project was to advance portable fuel cell system technology towards the commercial targets of power density, energy density and lifetime. These targets were laid out in the DOE’s R&D roadmap to develop an advanced direct methanol fuel cell power supply that meets commercial entry requirements. Such a power supply will enable mobile computers to operate non-stop, unplugged from the wall power outlet, by using the high energy density of methanol fuel contained in a replaceable fuel cartridge. Specifically this project focused on balance-of-plant component integration and miniaturization, as well as extensive component, subassembly and integrated system durability and validation testing. This design has resulted in a pre-production power supply design and a prototype that meet the rigorous demands of consumer electronic applications. PROJECT TASKS The proposed work plan was designed to meet the project objectives, which corresponded directly with the objectives outlined in the Funding Opportunity Announcement: To engineer the fuel cell balance-of-plant and packaging to meet the needs of consumer electronic systems, specifically at power levels required for mobile computing. UNF used existing balance-of-plant component technologies developed under its current US Army CERDEC project, as well as a previous DOE project completed by PolyFuel, to further refine them to both miniaturize and integrate their functionality to increase the system power density and energy density. Benefits of UNF’s novel passive water recycling MEA (membrane electrode assembly) and the simplified system architecture it enabled formed the foundation of the design approach. The package design was hardened to address orientation independence, shock, vibration, and environmental requirements. Fuel cartridge and fuel subsystems were improved to ensure effective fuel

  17. A Mobile Robots Experimental Environment with Event-Based Wireless Communication

    PubMed Central

    Guinaldo, María; Fábregas, Ernesto; Farias, Gonzalo; Dormido-Canto, Sebastián; Chaos, Dictino; Sánchez, José; Dormido, Sebastián

    2013-01-01

    An experimental platform to communicate between a set of mobile robots through a wireless network has been developed. The mobile robots get their position through a camera which performs as sensor. The video images are processed in a PC and a Waspmote card sends the corresponding position to each robot using the ZigBee standard. A distributed control algorithm based on event-triggered communications has been designed and implemented to bring the robots into the desired formation. Each robot communicates to its neighbors only at event times. Furthermore, a simulation tool has been developed to design and perform experiments with the system. An example of usage is presented. PMID:23881139

  18. A mobile robots experimental environment with event-based wireless communication.

    PubMed

    Guinaldo, María; Fábregas, Ernesto; Farias, Gonzalo; Dormido-Canto, Sebastián; Chaos, Dictino; Sánchez, José; Dormido, Sebastián

    2013-01-01

    An experimental platform to communicate between a set of mobile robots through a wireless network has been developed. The mobile robots get their position through a camera which performs as sensor. The video images are processed in a PC and a Waspmote card sends the corresponding position to each robot using the ZigBee standard. A distributed control algorithm based on event-triggered communications has been designed and implemented to bring the robots into the desired formation. Each robot communicates to its neighbors only at event times. Furthermore, a simulation tool has been developed to design and perform experiments with the system. An example of usage is presented. PMID:23881139

  19. Communication satellite studies applicable to mobile telephone services

    NASA Technical Reports Server (NTRS)

    Anderson, R. E.; Milton, R. T.; Brown, J. P.

    1979-01-01

    The potential use of satellites as extensions of existing terrestrial land mobile systems is discussed. Compatibility, particularly with cellular type systems, is considered. Sample technical and cost parameters and market assessments are also presented.

  20. TDMA-based dual-mode communication for mobile wireless sensor networks.

    PubMed

    Mehta, Ankur; Kerkez, Branko; Glaser, Steven D; Pister, Kristofer S J

    2012-01-01

    Small highly mobile robots, and in particular micro air vehicles (MAVs), are well suited to the task of exploring unknown indoor environments such as buildings and caves. Such a task imposes a number of requirements on the underlying communication infrastructure, with differing goals during various stages of the mission. This work addresses those requirements with a hybrid communications infrastructure consisting of a stationary mesh network along with the mobile nodes. The combined network operates in two independent modes, coupling a highly efficient, low duty cycle, low throughput mode for routing and persistent sensing with a burst mode for high data rate communication. By strategically distributing available frequency channels between the mobile agents and the stationary nodes, the overall network provides reliable long-term communication paths while maximizing data throughput when needed. PMID:23443374

  1. TDMA-Based Dual-Mode Communication for Mobile Wireless Sensor Networks

    PubMed Central

    Mehta, Ankur; Kerkez, Branko; Glaser, Steven D.; Pister, Kristofer S. J.

    2012-01-01

    Small highly mobile robots, and in particular micro air vehicles (MAVs), are well suited to the task of exploring unknown indoor environments such as buildings and caves. Such a task imposes a number of requirements on the underlying communication infrastructure, with differing goals during various stages of the mission. This work addresses those requirements with a hybrid communications infrastructure consisting of a stationary mesh network along with the mobile nodes. The combined network operates in two independent modes, coupling a highly efficient, low duty cycle, low throughput mode for routing and persistent sensing with a burst mode for high data rate communication. By strategically distributing available frequency channels between the mobile agents and the stationary nodes, the overall network provides reliable long-term communication paths while maximizing data throughput when needed. PMID:23443374

  2. Network design consideration of a satellite-based mobile communications system

    NASA Technical Reports Server (NTRS)

    Yan, T.-Y.

    1986-01-01

    Technical considerations for the Mobile Satellite Experiment (MSAT-X), the ground segment testbed for the low-cost spectral efficient satellite-based mobile communications technologies being developed for the 1990's, are discussed. The Network Management Center contains a flexible resource sharing algorithm, the Demand Assigned Multiple Access scheme, which partitions the satellite transponder bandwidth among voice, data, and request channels. Satellite use of multiple UHF beams permits frequency reuse. The backhaul communications and the Telemetry, Tracking and Control traffic are provided through a single full-coverage SHF beam. Mobile Terminals communicate with the satellite using UHF. All communications including SHF-SHF between Base Stations and/or Gateways, are routed through the satellite. Because MSAT-X is an experimental network, higher level network protocols (which are service-specific) will be developed only to test the operation of the lowest three levels, the physical, data link, and network layers.

  3. Analyzing Cultural Usability of Mobile Keypad and Displays for Textual Communication in Internationalization and Localization Perspectives

    NASA Astrophysics Data System (ADS)

    Orngreen, Rikke; Katre, Dinesh; Sandeep, Mulagapati

    The aim of this paper is to identify the cultural usability aspects that need to be considered while internationalizing or localizing the interaction design of mobile keypads and displays for textual communication. The analysis is based primarily on heuristics tests, where: Hindi, Arabic and Danish mobile phones are evaluated based on assumptions of user needs, and in comparison to English. We have also referred the existing research on Chinese mobile phones to further complement our work. The study provides an insight into the much needed local-language centred approach in contrast with the current English centred approach of existing mobile keypad designs and display of text.

  4. Need for, and financial feasibility of, satellite-aided land mobile communications

    NASA Astrophysics Data System (ADS)

    Castruccio, P. A.; Marantz, C. S.; Freibaum, J.

    Questions regarding the role of a mobile-satellite system in augmenting the terrestrial communications system are considered, and a market assessment study is discussed. Aspects of an investment analysis are examined, taking into account a three phase financial study of four postulated land Mobile Satellite Service (LMSS) systems, project profitability evaluation methods, risk analysis methods, financial projections, potential investor acceptance standards, and a risk analysis. It is concluded that a satellite augmented terrestrial mobile service appears to be economically and technically superior to a service depending exclusively on terrestrial systems. The interest in the Mobile Satellite Service is found to be worldwide, and the ground equipment market is potentially large.

  5. Need for, and financial feasibility of, satellite-aided land mobile communications

    NASA Technical Reports Server (NTRS)

    Castruccio, P. A.; Marantz, C. S.; Freibaum, J.

    1982-01-01

    Questions regarding the role of a mobile-satellite system in augmenting the terrestrial communications system are considered, and a market assessment study is discussed. Aspects of an investment analysis are examined, taking into account a three phase financial study of four postulated land Mobile Satellite Service (LMSS) systems, project profitability evaluation methods, risk analysis methods, financial projections, potential investor acceptance standards, and a risk analysis. It is concluded that a satellite augmented terrestrial mobile service appears to be economically and technically superior to a service depending exclusively on terrestrial systems. The interest in the Mobile Satellite Service is found to be worldwide, and the ground equipment market is potentially large.

  6. Real-time compressed video ultrasound using the Advanced Communications Technology Satellite

    NASA Astrophysics Data System (ADS)

    Stewart, Brent K.; Carter, Stephen J.; Cook, Jay F.; Abbe, Brian S.; Pinck, Deborah; Rowberg, Alan H.

    1996-05-01

    The authors have an in-kind grant from NASA to investigate the application of the Advanced Communications Technology Satellite (ACTS) to teleradiology and telemedicine using the Jet Propulsion Laboratory developed ACTS Mobile Terminal (AMT) uplink. We have recently completed three series of experiments with the ACTS/AMT. Although these experiments were multifaceted, the primary objective was the determination and evaluation of transmitting real- time compressed ultrasound video imagery over the ACTS/AMT satellite link, a primary focus of the author's current ARPA Advanced Biomedical Technology contract. These experiments have demonstrated that real-time compressed ultrasound video imagery can be transmitted over multiple ISDN line bandwidth links with sufficient temporal, contrast and spatial resolution for clinical diagnosis of multiple disease and pathology states to provide subspecialty consultation and education at a distance.

  7. Mobile Technology and the Challenge to Promote a Communicative City in Indonesia. Case Study Bandung Metropolitan Area

    ERIC Educational Resources Information Center

    Sutriadi, Ridwan

    2011-01-01

    The objective of this study is to assess the role of mobile technology to promote a communicative city in Indonesia. The focus is on mobile technologies as symbols of the latest information and communication technology (ICT). Communication influences the capacity building of the governmental planning employees to conduct better planning…

  8. Laser Communication Demonstration System (LCDS) and future mobile satellite services

    NASA Technical Reports Server (NTRS)

    Chen, Chien-Chung; Wilhelm, Michael D.; Lesh, James R.

    1995-01-01

    The Laser Communications Demonstration System (LCDS) is a proposed in-orbit demonstration of high data rate laser communications technology conceived jointly by NASA and U.S. industry. The program objectives are to stimulate industry development and to demonstrate the readiness of high data rate optical communications in Earth orbit. For future global satellite communication systems using intersatellite links, laser communications technology can offer reduced mass and power requirements and higher channel bandwidths without regulatory constraints. As currently envisioned, LCDS will consist of one or two orbiting laser communications terminals capable of demonstrating high data rate (greater than 750Mbps) transmission in a dynamic space environment. Two study teams led by Motorola and Ball Aerospace are currently in the process of conducting a Phase A/B mission definition study of LCDS under contracts with JPL/NASA. The studies consist of future application survey, concept and requirements definition, and a point design of the laser communications flight demonstration. It is planned that a single demonstration system will be developed based on the study results. The Phase A/B study is expected to be completed by the coming June, and the current results of the study are presented in this paper.

  9. ACTS Mobile Terminals

    NASA Technical Reports Server (NTRS)

    Abbe, Brian S.; Agan, Martin J.; Jedrey, Thomas C.

    1997-01-01

    The development of the Advanced Communications Technology Satellite (ACTS) Mobile Terminal (AMT) and its follow-on, the Broadband Aeronautical Terminal (BAT), have provided an excellent testbed for the evaluation of K- and Ka-band mobile satellite communications systems. An overview of both of these terminals is presented in this paper.

  10. Mobile phones and elderly people: a noisy communication.

    PubMed

    Stamato, Cláudia; Moraes, Anamaria de

    2012-01-01

    Knowing the users is capital for building user-friendly digital interfaces. One way to think about the users is considering their familiarity with this technology. This article presents the results of twelve interviews with elderly people residing in the so-called South Zone of Rio de Janeiro (Brazil) who have used mobile phones over at least one year. It is part of the Doctor's Thesis "Mobile phones for elderly people - usability for social integration" ("Celulares para idosos - usabilidade a serviço da integração social"), which is targeted at ascertaining if the current mobile phones are user-friendly for elderly people. Through the technique of Guided Interviews, we found usage time, criteria for choice of phones, reasons for changes, preferences, and manners of use. Preliminarily, we have noticed differences in the behavior of the participating users and performed a qualitative analysis according to groups of age and gender. PMID:22316743

  11. Satellite-aided land mobile communications system implementation considerations

    NASA Technical Reports Server (NTRS)

    Leroy, B. E.

    1982-01-01

    It was proposed that a satellite-based land mobile radio system could effectively extend the terrestrial cellular mobile system into rural and remote areas. The market, technical and economic feasibility for such a system is studied. Some of the aspects of implementing an operational mobile-satellite system are discussed. In particular, two key factors in implementation are examined: (1) bandwidth requirements; and (2) frequency sharing. Bandwidth requirements are derived based on the satellite antenna requirements, modulation characteristics and numbers of subscribers. Design trade-offs for the satellite system and potential implementation scenarios are identified. Frequency sharing is examined from a power flux density and modulation viewpoint. Previously announced in STAR as N82-25290

  12. [Pilot plan for a mobile health communication and monitoring system for people with diabetes].

    PubMed

    Alcayaga, Claudia; Pérez, Janet Carola; Bustamante, Claudia; Campos, Solange; Lange, Ilta; Zuñiga, Francisca

    2014-01-01

    mHealth is a practical, useful, and available tool for one-way or two-way communication between health professionals and patients. It is especially promising in countries such as Chile, with widespread and growing mobile telephone coverage that is very well accepted by the public. Our objective is to demonstrate the process for designing a mobile communication and monitoring model, aimed at providing communication between professionals in primary healthcare centers and their patients, to facilitate timely diagnosis and initiation of treatment for type 2 diabetes. This model's characteristics include use of mobile telephones as a communication tool, a one-way method (from health centers to patients), integration into in-person care delivered at health centers, use of different communication strategies (voice and written), and integrated functioning using open-source software. The system includes personalized communication, automated voice communication, and automated written communication using short message service (SMS). We describe the strategies and components of the system. The lessons learned include the contribution from successful implementation of COSMOS (consolidated online modulated operating systems), a technological innovation, to support the health care of people with suspected type 2 diabetes in primary healthcare centers. Working together with teams in the field is essential to this achievement. PMID:25211577

  13. Overview of NASA Glenn Aero/Mobile Communications Demonstrations

    NASA Technical Reports Server (NTRS)

    Brooks, David; Hoder, Doug; Wilkins, Ryan

    2004-01-01

    The Glenn Research Center at Lewis Field (GRC) has been involved with several other NASA field centers on various networking and RF communications demonstrations and experiments since 1998. These collaborative experiments investigated communications technologies new to aviation, such as wideband Ku satcom, L-band narrowband satcom, and IP (Internet Protocol), using commercial off-the-shelf (COTS) components These technologies can be used to distribute weather and hazard data, air traffic management and airline fleet management information, and passenger cabin Internet service.

  14. Overview of NASA Glenn Aero/Mobile Communication Demonstrations

    NASA Technical Reports Server (NTRS)

    Brooks, David; Hoder, Doug; Wilkins, Ryan

    2004-01-01

    The Glenn Research Center at Lewis Field (GRC) has been involved with several other NASA field centers on various networking and RF communications demonstrations and experiments since 1998. These collaborative experiments investigated communications technologies new to aviation, such as wideband Ku satcom, L-band narrowband satcom, and IP (Internet Protocol), using commercial off-the-shelf (COTS) components These technologies can be used to distribute weather and hazard data, air traffic management and airline fleet management information, and passenger cabin Internet service.

  15. SHER: A Colored Petri Net Based Random Mobility Model for Wireless Communications

    PubMed Central

    Khan, Naeem Akhtar; Ahmad, Farooq; Khan, Sher Afzal

    2015-01-01

    In wireless network research, simulation is the most imperative technique to investigate the network’s behavior and validation. Wireless networks typically consist of mobile hosts; therefore, the degree of validation is influenced by the underlying mobility model, and synthetic models are implemented in simulators because real life traces are not widely available. In wireless communications, mobility is an integral part while the key role of a mobility model is to mimic the real life traveling patterns to study. The performance of routing protocols and mobility management strategies e.g. paging, registration and handoff is highly dependent to the selected mobility model. In this paper, we devise and evaluate the Show Home and Exclusive Regions (SHER), a novel two-dimensional (2-D) Colored Petri net (CPN) based formal random mobility model, which exhibits sociological behavior of a user. The model captures hotspots where a user frequently visits and spends time. Our solution eliminates six key issues of the random mobility models, i.e., sudden stops, memoryless movements, border effect, temporal dependency of velocity, pause time dependency, and speed decay in a single model. The proposed model is able to predict the future location of a mobile user and ultimately improves the performance of wireless communication networks. The model follows a uniform nodal distribution and is a mini simulator, which exhibits interesting mobility patterns. The model is also helpful to those who are not familiar with the formal modeling, and users can extract meaningful information with a single mouse-click. It is noteworthy that capturing dynamic mobility patterns through CPN is the most challenging and virulent activity of the presented research. Statistical and reachability analysis techniques are presented to elucidate and validate the performance of our proposed mobility model. The state space methods allow us to algorithmically derive the system behavior and rectify the

  16. SHER: a colored petri net based random mobility model for wireless communications.

    PubMed

    Khan, Naeem Akhtar; Ahmad, Farooq; Khan, Sher Afzal

    2015-01-01

    In wireless network research, simulation is the most imperative technique to investigate the network's behavior and validation. Wireless networks typically consist of mobile hosts; therefore, the degree of validation is influenced by the underlying mobility model, and synthetic models are implemented in simulators because real life traces are not widely available. In wireless communications, mobility is an integral part while the key role of a mobility model is to mimic the real life traveling patterns to study. The performance of routing protocols and mobility management strategies e.g. paging, registration and handoff is highly dependent to the selected mobility model. In this paper, we devise and evaluate the Show Home and Exclusive Regions (SHER), a novel two-dimensional (2-D) Colored Petri net (CPN) based formal random mobility model, which exhibits sociological behavior of a user. The model captures hotspots where a user frequently visits and spends time. Our solution eliminates six key issues of the random mobility models, i.e., sudden stops, memoryless movements, border effect, temporal dependency of velocity, pause time dependency, and speed decay in a single model. The proposed model is able to predict the future location of a mobile user and ultimately improves the performance of wireless communication networks. The model follows a uniform nodal distribution and is a mini simulator, which exhibits interesting mobility patterns. The model is also helpful to those who are not familiar with the formal modeling, and users can extract meaningful information with a single mouse-click. It is noteworthy that capturing dynamic mobility patterns through CPN is the most challenging and virulent activity of the presented research. Statistical and reachability analysis techniques are presented to elucidate and validate the performance of our proposed mobility model. The state space methods allow us to algorithmically derive the system behavior and rectify the errors

  17. Radiation-Hardened Electronics for Advanced Communications Systems

    NASA Technical Reports Server (NTRS)

    Whitaker, Sterling

    2015-01-01

    Novel approach enables high-speed special-purpose processors Advanced reconfigurable and reprogrammable communication systems will require sub-130-nanometer electronics. Legacy single event upset (SEU) radiation-tolerant circuits are ineffective at speeds greater than 125 megahertz. In Phase I of this project, ICs, LLC, demonstrated new base-level logic circuits that provide SEU immunity for sub-130-nanometer high-speed circuits. In Phase II, the company developed an innovative self-restoring logic (SRL) circuit and a system approach that provides high-speed, SEU-tolerant solutions that are effective for sub-130-nanometer electronics scalable to at least 22-nanometer processes. The SRL system can be used in the design of NASA's next-generation special-purpose processors, especially reconfigurable communication processors.

  18. Improved orthogonal frequency division multiplexing communications through advanced coding

    NASA Astrophysics Data System (ADS)

    Westra, Jeffrey; Patti, John

    2005-08-01

    Orthogonal Frequency Division Multiplexing (OFDM) is a communications technique that transmits a signal over multiple, evenly spaced, discrete frequency bands. OFDM offers some advantages over traditional, single-carrier modulation techniques, such as increased immunity to inter-symbol interference. For this reason OFDM is an attractive candidate for sensor network application; it has already been included in several standards, including Digital Audio Broadcast (DAB); digital television standards in Europe, Japan and Australia; asymmetric digital subscriber line (ASDL); and wireless local area networks (WLAN), specifically IEEE 802.11a. Many of these applications currently make use of a standard convolutional code with Viterbi decoding to perform forward error correction (FEC). Replacing such convolutional codes with advanced coding techniques using iterative decoding, such as Turbo codes, can substantially improve the performance of the OFDM communications link. This paper demonstrates such improvements using the 802.11a wireless LAN standard.

  19. Collaborating with Your Clients Using Social Media & Mobile Communications

    ERIC Educational Resources Information Center

    Typhina, Eli; Bardon, Robert E.; Gharis, Laurie W.

    2015-01-01

    Many Extension educators are still learning how to effectively integrate social media into their programs. By using the right social media platforms and mobile applications to create engaged, online communities, Extension educators can collaborate with clients to produce and to share information expanding and enhancing their social media and…

  20. Proceedings of the Seventeenth NASA Propagation Experimenters Meeting (NAPEX 17) and the Advanced Communications Technology Satellite (ACTS) Propagation Studies Miniworkshop

    NASA Technical Reports Server (NTRS)

    Davarian, Faramaz (Editor)

    1993-01-01

    The NASA Propagation Experimenters Meeting (NAPEX) is convened annually to discuss studies made on radio wave propagation by investors from domestic and international organizations. NAPEX 17 was held on 15 June 1993. The meeting was organized into two technical sessions. The first session was dedicated to slant path propagation studies and experiments. The second session focused on propagation studies for mobile and personal communications. Preceding NAPEX 17, the Advanced Communications Technology Satellite (ACTS) Propagation Studies Miniworkshop was held on 14 June 1993 to review ACTS propagation activities with emphasis on ACTS experiments status and data collection, processing, and exchange.

  1. Advanced EHF technologies for lightweight augmentation/restoration communications satellites

    NASA Astrophysics Data System (ADS)

    Kolba, Dean P.; Greenberg, William L.; McElroy, David R.; Semprucci, Marilyn D.

    Small EHF satellites can significantly complement the anti-jam service provided by basic EHF MILSATCOM space segments. Mobile/survivable launch vehicles with rapid launch preparations can be utilized to responsively deploy these small satellites into high-altitude elliptical or circular orbits. From such orbits, only a few satellites are needed to provide high-duty-cycle coverage of a critical area. The communications capabilities provided by these EHF payloads can range from (75-2400 bps per channel to 10 Mbps or more per links, depending on the payload configuration. Through the use of EHF waveform standards, these augmentation/restoration satellites will be compatible with existing and planned EHF terminals.

  2. Analysis of the grounding system for a mobile communication site placed on HV power line mast

    NASA Astrophysics Data System (ADS)

    Bîrsan, I.; Munteanu, C.; Horgoș, M.; Ilut, T.

    2016-08-01

    This paper aims to analyze the potential distribution on the soil surface or potential variation on the main directions inside computing mobile site. I want to study a system made the earth a mobile communications site, antennas operator and the system of which the earth is placed on a High Voltage Power Line Mast (LEA 110 KV). I made direct measurements and I use a 3D software for analyze the results and simulating some possible solutions.

  3. An operational open-end file transfer protocol for mobile satellite communications

    NASA Technical Reports Server (NTRS)

    Wang, Charles; Cheng, Unjeng; Yan, Tsun-Yee

    1988-01-01

    This paper describes an operational open-end file transfer protocol which includes the connecting procedure, data transfer, and relinquishment procedure for mobile satellite communications. The protocol makes use of the frame level and packet level formats of the X.25 standard for the data link layer and network layer, respectively. The structure of a testbed for experimental simulation of this protocol over a mobile fading channel is also introduced.

  4. Lightweight, mobile E-mail for intra-clinic communication.

    PubMed Central

    Acuff, R. D.; Fagan, L. M.; Rindfleisch, T. C.; Levitt, B. J.; Ford, P. M.

    1997-01-01

    We have developed a mobile messaging system designed for use in the clinic setting. The system is designed to facilitate quick, informal, interactions that occur in a clinical setting, e.g., requests for assistance or information. The system includes safeguards to make sure that the sender of a message is aware if a message is not read in a timely fashion. Evaluation of the system shows message delivery was about 50% slower than our target of 30 seconds. Although the mobile device used is fairly small when combined with a radio unit, it is too bulky and users did not necessarily carry the system with them. This led to delays (over eleven minutes on average) before messages were seen. We expect that improvements in hardware and clinical software will lead to more common use of such adjunct software systems. PMID:9357721

  5. High-Speed Mobile Communications in Hostile Environments

    NASA Astrophysics Data System (ADS)

    Agosta, S.; Sierra, R.; Chapron, F.

    2015-12-01

    With the inexorable increase in the use of mobile devices, wireless connectivity is expected by users anywhere, anytime. In general, this requirement is addressed in office buildings or public locations through the use of Wi-Fi technology but Wi-Fi is not well adapted for use in large experiment halls and complex underground environments, especially those where radiation exposure is an issue, such as the LHC tunnel and experimental caverns. 4G/LTE technology, however, looks to be well adapted to addressing mobility needs in such areas. We report here the studies CERN has undertaken on the use of 4G/LTE in the LHC tunnel, presenting results on the data throughput that can be achieved and discussing issues such as the provision of a consistent user experience.

  6. Leveraging mobile smart devices to improve interprofessional communications in inpatient practice setting: A literature review.

    PubMed

    Aungst, Timothy Dy; Belliveau, Paul

    2015-01-01

    As mobile smart device use has increased in society, the healthcare community has begun using these devices for communication among professionals in practice settings. The purpose of this review is to describe primary literature which reports on the experiences with interprofessional healthcare communication via mobile smart devices. Based on these findings, this review also addresses how these devices may be utilized to facilitate interprofessional education (IPE) in health professions education programs. The literature search revealed limited assessments of mobile smart device use in clinical practice settings. In available reports, communication with mobile smart devices was perceived as more effective and faster among interdisciplinary members. Notable drawbacks included discrepancies in the urgency labeling of messages, increased interruptions associated with constant accessibility to team members, and professionalism breakdowns. Recently developed interprofessional competencies include an emphasis on ensuring that health profession students can effectively communicate on interprofessional teams. With the increasing reliance on mobile smart devices in the absence of robust benefit and risk assessments on their use in clinical practice settings, use of these devices may be leveraged to facilitate IPE activities in health education professions programs while simultaneously educating students on their proper use in patient care settings. PMID:26652629

  7. "Going Mobile" in Business Communication at an Arabian Gulf University

    ERIC Educational Resources Information Center

    Rapanta, Chrysi; Nickerson, Catherine; Goby, Valerie Priscilla

    2014-01-01

    In this article, we describe a project in which undergraduate business seniors at a university in the Arabian Gulf created or evaluated the chapters of an iBook as part of their final course in business communication. Students were surveyed throughout the project, and they also participated in a focus group discussion at the end. The aim was to…

  8. [The role of mobile communication devices in the spread of infections].

    PubMed

    Morvai, Júlia; Szabó, Rita

    2015-05-17

    Mobile communication devices have an invaluable feature of communication within hospital, and they may support certain aspects of clinical diagnosis and education. However, there may be a risk for contamination of these devices with various pathogens. The aim of the authors was to perform a systematic review on the potential role of mobile communication devices in the dissemination of pathogens and to identify effective prevention measures. A detailed literature search was conducted using PubMed and ScienceDirect databases for papers published in English between January, 2004 and August, 2014. With the use of specific search term combinations 30 of the 216 articles met the inclusion criteria. It was found that only 8% of healthcare workers routinely cleaned their mobile communication devices resulting in a high rate of contamination (40-100%). Coagulase-negative Staphylococci and Staphylococcus aureus were the most commonly identified bacteria and most of them were methicillin resistant (10-95.3%). This systematic review identified effective interventions to reduce bacterial contamination risks including staff education, hand hygiene and regular decontamination of mobile communication devices. PMID:26038946

  9. Assessing reliable human mobility patterns from higher order memory in mobile communications.

    PubMed

    Matamalas, Joan T; De Domenico, Manlio; Arenas, Alex

    2016-08-01

    Understanding how people move within a geographical area, e.g. a city, a country or the whole world, is fundamental in several applications, from predicting the spatio-temporal evolution of an epidemic to inferring migration patterns. Mobile phone records provide an excellent proxy of human mobility, showing that movements exhibit a high level of memory. However, the precise role of memory in widely adopted proxies of mobility, as mobile phone records, is unknown. Here we use 560 million call detail records from Senegal to show that standard Markovian approaches, including higher order ones, fail in capturing real mobility patterns and introduce spurious movements never observed in reality. We introduce an adaptive memory-driven approach to overcome such issues. At variance with Markovian models, it is able to realistically model conditional waiting times, i.e. the probability to stay in a specific area depending on individuals' historical movements. Our results demonstrate that in standard mobility models the individuals tend to diffuse faster than observed in reality, whereas the predictions of the adaptive memory approach significantly agree with observations. We show that, as a consequence, the incidence and the geographical spread of a disease could be inadequately estimated when standard approaches are used, with crucial implications on resources deployment and policy-making during an epidemic outbreak. PMID:27581479

  10. Advanced Communications Technology Satellite Now Operating in an Inclined Orbit

    NASA Technical Reports Server (NTRS)

    Bauer, Robert A.

    1999-01-01

    The Advanced Communications Technology Satellite (ACTS) system has been modified to support operation in an inclined orbit that is virtually transparent to users, and plans are to continue this final phase of its operation through September 2000. The next 2 years of ACTS will provide a new opportunity for using the technologies that this system brought online over 5 years ago and that are still being used to resolve the technical issues that face NASA and the satellite industry in the area of seamless networking and interoperability with terrestrial systems. New goals for ACTS have been defined that align the program with recent changes in NASA and industry. ACTS will be used as a testbed to: Show how NASA and other Government agencies can use commercial systems for 1. future support of their operations Test, characterize, and resolve technical issues in using advanced communications 2. protocols such as asynchronous transfer mode (ATM) and transmission control protocol/Internet protocol (TCP/IP) over long latency links as found when interoperating satellites with terrestrial systems Evaluate narrow-spot-beam Ka-band satellite operation in an inclined orbit 3. Verify Ka-band satellite technologies since no other Ka-band system is yet 4. available in the United States

  11. Transportation and Aging: A Research Agenda for Advancing Safe Mobility

    ERIC Educational Resources Information Center

    Dickerson, Anne E.; Molnar, Lisa J.; Eby, David W.; Adler, Geri; Bedard, Michel; Berg-Weger, Marla; Classen, Sherrilene; Foley, Daniel; Horowitz, Amy; Kerschner, Helen; Page, Oliver; Silverstein, Nina M.; Staplin, Loren; Trujillo, Leonard

    2007-01-01

    Purpose: We review what we currently know about older driver safety and mobility, and we highlight important research needs in a number of key areas that hold promise for achieving the safety and mobility goals for the aging baby boomers and future generations of older drivers. Design and Methods: Through the use of a framework for transportation…

  12. Simulating data processing for an Advanced Ion Mobility Mass Spectrometer

    SciTech Connect

    Chavarría-Miranda, Daniel; Clowers, Brian H.; Anderson, Gordon A.; Belov, Mikhail E.

    2007-11-03

    We have designed and implemented a Cray XD-1-based sim- ulation of data capture and signal processing for an ad- vanced Ion Mobility mass spectrometer (Hadamard trans- form Ion Mobility). Our simulation is a hybrid application that uses both an FPGA component and a CPU-based soft- ware component to simulate Ion Mobility mass spectrome- try data processing. The FPGA component includes data capture and accumulation, as well as a more sophisticated deconvolution algorithm based on a PNNL-developed en- hancement to standard Hadamard transform Ion Mobility spectrometry. The software portion is in charge of stream- ing data to the FPGA and collecting results. We expect the computational and memory addressing logic of the FPGA component to be portable to an instrument-attached FPGA board that can be interfaced with a Hadamard transform Ion Mobility mass spectrometer.

  13. Networked sensors for the future force (NSFF) advanced technology demonstration (ATD) communications systems

    NASA Astrophysics Data System (ADS)

    Nemeroff, Jay; DiPierro, Stefano

    2005-05-01

    The U.S. Army"s Future Combat Systems (FCS) and Future Force Warrior (FFW) will rely on the use of unattended, tactical sensors to detect and identify enemy targets in order to avoid enemy fires and enable precise networked fire to survive on the future battlefield with less armor protection. Successful implementation of these critical sensor fields requires the development of a specialized communications network infrastructure needed to disseminate sensor data to provide relevant, timely and accurate situational awareness information to the tactical common operating picture. The sensor network communications must support both static deployed and mobile ground and air robotic sensor arrays with robust, secure, stealthy, and jam resistant links. It is envisioned that tactical sensor networks can be deployed in a two tiered communications architecture that includes a lower sensor sub-layer consisting of acoustic, magnetic, Chemical/Biological and seismic detectors and an upper sub-layer consisting of infrared or visual imaging cameras. The upper sub-layer can be cued by the lower sub-layer and provides a seamless gateway link to higher echelon backbone tactical networks. The NSFF Advanced Technology Demonstration (ATD) communications effort focuses on providing Future Force systems such as the FCS and the Future Force Warrior with critical situational awareness data needed for survivability. The communications systems supporting this functionality must be designed such that unattended ground sensor data can flow seamlessly from the lowest unattended tactical sensor echelons into the Army"s tactical backbone networks while also allowing the "fusing" of the data with other intelligence information for correlation within a tactical command and control node. NSFF is realizing this capability by using advanced communications technologies developed under the Soldier Level Integrated Communications Environment (SLICE) Soldier Radio Waveform (SRW) project. These technologies

  14. [Problems of harmonization of sanitary regulations of the electromagnetic fields of mobile radio communication equipment].

    PubMed

    Pal'tsev, Iu P; Pokhodzeĭ, L V; Rubtsova, N B; Bogacheva, E V

    2013-01-01

    In the article there are presented data on the probable adverse effects of electromagnetic fields generated by means of mobile cellulary radio communication equipment, a comparative analysis of hygienic rating and methods of measurement of their parameters in Russia and abroad has been performed, and the ways of harmonizing hygienic rules have been outlined, the necessity of further research to risk assessment of the use of cellular radio communication devices by population and preventive measures have been substantiated. PMID:24340578

  15. A new coherent demodulation technique for land-mobile satellite communications

    NASA Technical Reports Server (NTRS)

    Yoshida, Shousei; Tomita, Hideho

    1990-01-01

    An advanced coherent demodulation technique is described for land mobile satellite (LMS) communications. The proposed technique features a combined narrow/wind band dual open loop carrier phase estimator, which is effectively able to compensate the fast carrier phase fluctuation by fading with sacrificing a phase slip rate. Also included is the realization of quick carrier and clock reacquisition after shadowing by taking open loop structure. Its bit error rate (BER) performance is superior to that of existing detection schemes, showing a BER of 1 x 10(exp -2) at 6.3 dB E sub b/N sub o over the Rician channel with 10 dB C/M and 200 Hz (1/16 modulation rate) fading pitch f sub d for QPSK. The proposed scheme consists of a fast response carrier recovery and a quick bit timing recovery with an interpolation. An experimental terminal model was developed to evaluate its performance at fading conditions. The results are quite satisfactory, giving prospects for future LMS applications.

  16. Implementation of LSCMA adaptive array terminal for mobile satellite communications

    NASA Astrophysics Data System (ADS)

    Zhou, Shun; Wang, Huali; Xu, Zhijun

    2007-11-01

    This paper considers the application of adaptive array antenna based on the least squares constant modulus algorithm (LSCMA) for interference rejection in mobile SATCOM terminals. A two-element adaptive array scheme is implemented with a combination of ADI TS201S DSP chips and Altera Stratix II FPGA device, which makes a cooperating computation for adaptive beamforming. Its interference suppressing performance is verified via Matlab simulations. Digital hardware system is implemented to execute the operations of LSCMA beamforming algorithm that is represented by an algorithm flowchart. The result of simulations and test indicate that this scheme can improve the anti-jamming performance of terminals.

  17. Secure communication of medical information using mobile agents.

    PubMed

    Nikooghadam, Morteza; Zakerolhosseini, Ali

    2012-12-01

    Recently several efficient schemes are proposed to provide security of e-medicine systems. Almost all of these schemes have tried to achieve the highest security level in transmission of patients' medical information to medical institutions through a heterogeneous network like Internet. In this paper, we explain the insecurity of these schemes against "man-in-the-middle" attack. Furthermore, a dynamic mobile agent system based on hybrid cryptosystem is proposed that is both secure and also efficient in computation cost. Analyzing the security criteria confirms suitability of the proposed scheme for e-medicine systems. PMID:22569875

  18. Toll free mobile communication: overcoming barriers in maternal and neonatal emergencies in Rural Bangladesh

    PubMed Central

    2014-01-01

    Background Toll free mobile telephone intervention to support mothers in pregnancy and delivery period was tested in one sub district of Bangladesh. Qualitative research was conducted to measure the changes of mobile phone use in increasing communication for maternal and neonatal complications. Methods In-depth interviews were conducted among twelve Community Skilled Birth Attendants and fourteen mothers along with their husbands prior to intervention. At intervention end, six Community Skilled Birth Attendants were purposively selected for in-depth interview. Semi structured interviews were conducted among all 27 Community Skilled Birth Attendants engaged in the intervention. One Focus Group Discussion was conducted with 10 recently delivered mothers. Thematic analysis and triangulation of different responses were conducted. Results Prior to intervention, Community Skilled Birth Attendants reported that mobile communication was not a norm. It was also revealed that poor mothers had poor accessibility to mobile services. Mothers, who communicated through mobile phone with providers noted irritability from Community Skilled Birth Attendants and sometimes found phones switched off. At the end of the project, 85% of mothers who had attended orientation sessions of the intervention communicated with Community Skilled Birth Attendants through mobile phones during maternal health complications. Once a complication is reported or anticipated over phone, Community Skilled Birth Attendants either made a prompt visit to mothers or advised for direct referral. More than 80% Community Skilled Birth Attendants communicated with Solution Linked Group for guidance on maternal health management. Prior to intervention, Solution Linked Group was not used to receive phone call from Community Skilled Birth Attendants. Community Skilled Birth Attendants were valued by the mothers. Mothers viewed that Community Skilled Birth Attendants are becoming confident in managing complication due

  19. Downsizing Antenna Technologies for Mobile and Satellite Communications

    NASA Technical Reports Server (NTRS)

    Huang, J.; Densmore, A.; Tulintseff, A.; Jamnejad, V.

    1993-01-01

    Due to the increasing and stringent functional requirements (larger capacity, longer distances, etc.) of modern day communication systems, higher antenna gains are generally needed. This higher gain implies larger antenna size and mass which are undesirable to many systems. Consequently, downsizing antenna technology becomes one of the most critical areas for research and development efforts. Techniques to reduce antenna size can be categorized and are briefly discussed.

  20. An adaptive array antenna for mobile satellite communications

    NASA Technical Reports Server (NTRS)

    Milne, Robert

    1990-01-01

    The design of an adaptive array antenna for land vehicle operation and its performance in an operational satellite system is described. Linear and circularly polarized antenna designs are presented. The acquisition and tracking operation of a satellite is described and the effect on the communications signal is discussed. A number of system requirements are examined that have a major impact on the antenna design. The results of environmental, power handling, and RFI testing are presented and potential problems are identified.

  1. Stochastic Differential Equations for Modeling, Estimation and Identification of Mobile-to-Mobile Communication Channels

    SciTech Connect

    Olama, Mohammed M; Djouadi, Seddik M; Charalambous, Prof. Charalambos

    2009-01-01

    Mobile-to-mobile networks are characterized by node mobility that makes the propagation environment time varying and subject to fading. As a consequence, the statistical characteristics of the received signal vary continuously, giving rise to a Doppler power spectral density (DPSD) which varies from one observation instant to the next. The current models do not capture and track the time varying characteristics. This paper is concerned with dynamical modelling of mobile-to-mobile channels, parameter estimation and identification from received signal measurements. The evolution of the propagation environment is described by stochastic differential equations. In particular, it is shown that the parameters of the models can be determined by approximating the band-limited DPSD using the Gauss-Newton method. However, since the DPSD is not available online, we propose to use a filter-based expectation maximization algorithm and Kalman filter to estimate the channel parameters and states, respectively. The scheme results in a finite dimensional filter which only uses the first and second order statistics. The algorithm is recursive allowing the inphase and quadrature components and parameters to be estimated online from received signal measurements. The algorithms are tested using experimental data collected from moving sensor nodes in indoor and outdoor environments demonstrating the method s viability.

  2. Communication: Charge, diffusion, and mobility of proteins through nanopores

    PubMed Central

    Muthukumar, M.

    2014-01-01

    Implementation of Einstein's law connecting charge, diffusion coefficient, and mobility to interpret experimental data on proteins from single molecule electrophoresis through nanopores faces serious difficulties. The protein charge and diffusion coefficient, inferred with the Einstein law, can be orders of magnitude smaller than their bare values depending on the electrolyte concentration, pore diameter, chemical nature of the pore wall, and the externally applied voltage. The main contributors to the discrepancies are the coupled dynamics of the protein and its counterion cloud, confinement effects inside the pore, and the protein-pore-surface interaction. We have addressed these ingredients by harking on classical theories of electrophoresis of macroions and hydrodynamics inside pores, and deriving new results for pore-protein interactions. Putting together various components, we present approximate analytical formulas for the effective charge, diffusion coefficient, and mobility of a protein in the context of single molecule electrophoresis experiments. For the omnipresent pore-protein interactions, nonlinear dependence of the velocity of protein on voltage sets in readily and analytical formulas for this effect are presented. The derived formulas enable the determination of the bare charge and size of a protein from the experimentally measured apparent values. PMID:25172998

  3. Faculty Use and Perception of Mobile Information and Communication Technology (m-ICT) for Teaching Practices

    ERIC Educational Resources Information Center

    Biddix, J. Patrick; Chung, Chung Joo; Park, Han Woo

    2016-01-01

    The purpose of this study was to consider faculty use and perception of mobile information and communication technology (m-ICT) for teaching practices. The researchers examined qualitative responses about specific m-ICT use and efficiency amongst Korean and US faculty (n = 59) at three different institutions. Findings from multi-level textual…

  4. Communication Research, the Rockefeller Foundation, and Mobilization for the War on Words, 1938-1944.

    ERIC Educational Resources Information Center

    Gary, Brett

    1996-01-01

    Argues that Rockefeller Foundation served as an unofficial arm of the state from 1938 to 1944 by mobilizing social-scientific expertise to fight fascism when the Roosevelt Administration was politically unable to do so. Notes that Rockefeller Foundation officer John Marshall's role in the history of American mass communication research and the…

  5. Enhancing Motivation in Online Courses with Mobile Communication Tool Support: A Comparative Study

    ERIC Educational Resources Information Center

    Chaiprasurt, Chantorn; Esichaikul, Vatcharaporn

    2013-01-01

    Mobile technologies have helped establish new channels of communication among learners and instructors, potentially providing greater access to course information, and promoting easier access to course activities and learner motivation in online learning environments. The paper compares motivation between groups of learners being taught through an…

  6. 75 FR 8399 - In the Matter of Certain Mobile Communications and Computer Devices and Components Thereof...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-02-24

    ... COMMISSION In the Matter of Certain Mobile Communications and Computer Devices and Components Thereof; Notice... U.S.C. 1337, on behalf of Apple Inc., f/k/a Apple Computer, Inc. of Cupertino, California. The... computer devices and components thereof by reason of infringement of certain claims of U.S. Patent Nos....

  7. 78 FR 32689 - Certain Portable Electronic Communications Devices, Including Mobile Phones and Components...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-05-31

    ...Notice is hereby given that the U.S. International Trade Commission has received a complaint entitled Certain Portable Electronic Communications Devices, Including Mobile Phones and Components Thereof, DN 2958; the Commission is soliciting comments on any public interest issues raised by the complaint or complainant's filing under section 210.8(b) of the Commission's Rules of Practice and......

  8. 75 FR 44282 - In the Matter of Certain Mobile Telephones and Wireless Communication Devices Featuring Digital...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-07-28

    ... Company of Rochester, New York on January 14, 2010, and supplemented on February 4, 2010. 75 FR 8112. The... Cameras, and Components Thereof; Notice of Commission Determination To Review Initial Determination AGENCY... importation of certain mobile telephones and wireless communication devices featuring digital cameras,...

  9. [Solution of PACS to communicate with the handheld mobile intelligent equipment based on web service].

    PubMed

    Xue, Weijing; Wang, Pengcheng; Meng, Jian; Wang, Haiyang

    2013-09-01

    Using the Web Service technology, the paper puts forward a solution of remote communication between PACS and the handheld mobile intelligent devices, the characteristics of the solution are simple, easy to implement, short development cycle, high practicability, and low cost etc. PMID:24409803

  10. 77 FR 40083 - Certain Personal Data and Mobile Communications Devices and Related Software; Institution of a...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-07-06

    ... mobile communications devices and related software. 75 FR 17434 (Apr. 6, 2010). The complaint named as... claims. 76 FR 80402 (Dec. 23, 2011). An opinion accompanied the notice. The Commission issued a limited... April 6, 2010, based on a complaint filed by Apple Inc., and its subsidiary NeXT Software, Inc., both...

  11. 76 FR 80402 - Certain Personal Data and Mobile Communications Devices and Related Software; Final Determination...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-12-23

    ... mobile communications devices and related software that infringe certain U.S. patents. 75 FR 17434 (Apr... this investigation. 76 FR 58,537 (Sept. 21, 2011). The parties filed briefing on the issues under..., 2010, based on a complaint filed by Apple Inc., and its subsidiary NeXT Software, Inc., both...

  12. 75 FR 3914 - Recordation of Trade Name “Sony Ericsson Mobile Communications AB”

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-01-25

    ..., 2010. FOR FURTHER INFORMATION CONTACT: Suzanne E. Kane, Attorney-Advisor, Intellectual Property Rights... ``Sony Ericsson Mobile Communications AB'' in the Federal Register (74 FR 58042). The notice advised that... requires. Dated: January 15, 2010. Charles R. Steuart, Chief, Intellectual Property Rights &...

  13. How Can Mobile SMS Communication Support and Enhance a First Year Undergraduate Learning Environment?

    ERIC Educational Resources Information Center

    Jones, Geraldine; Edwards, Gabriele; Reid, Alan

    2009-01-01

    In this paper we discuss a case study investigating how the academic and personal development of first year students on an undergraduate sports education degree can be supported and enhanced with mobile SMS (Short Message Service) communication. SMS-based technologies were introduced in response to students' particular needs (in transition to…

  14. Performance analysis of replication ALOHA for fading mobile communications channels

    NASA Technical Reports Server (NTRS)

    Yan, Tsun-Yee; Clare, Loren P.

    1986-01-01

    This paper describes an ALOHA random access protocol for fading communications channels. A two-state Markov model is used for the channel error process to account for the channel fading memory. The ALOHA protocol is modified to send multiple contiguous copies of a message at each transmission attempt. Both pure and slotted ALOHA channels are considered. The analysis is applicable to fading environments where the channel memory is short compared to the propagation delay. It is shown that smaller delay may be achieved using replications and, in noisy conditions, can also improve throughput.

  15. Future mobile satellite communication concepts at 20/30 GHz

    NASA Technical Reports Server (NTRS)

    Barton, S. K.; Norbury, J. R.

    1990-01-01

    The outline of a design of a system using ultra small earth stations (picoterminals) for data traffic at 20/30 GHz is discussed. The picoterminals would be battery powered, have an RF transmitter power of 0.5 W, use a 10 cm square patch antenna, and have a receiver G/T of about -8 dB/K. Spread spectrum modulation would be required (due to interference consideration) to allow a telex type data link (less than 200 bit/s data rate) from the picoterminal to the hub station of the network and about 40 kbit/s on the outbound patch. An Olympus type transponder at 20/30 GHz could maintain several thousand simultaneous picoterminal circuits. The possibility of demonstrating a picoterminal network with voice traffic using Olympus is discussed together with fully mobile systems based on this concept.

  16. Design and evaluation of speech coders for mobile satellite communications

    NASA Astrophysics Data System (ADS)

    Copperi, M.; Perosino, F.; Biglieri, E.; Albertengo, G.

    The authors deal with the design and performance analysis of two real-time speech coder algorithms implemented on an array processor, i.e., a linear predictive coder (LPC) operating at 2.4 kb/s, and a baseband residual coder (BBC) operating at 7.2/9.6 kb/s. The effects of channel impairments typical of mobile satellite systems, such as multipath fading and shadowing, on the subjective quality is evaluated by means of the diagnostic rhyme test (DRT) and the diagnostic acceptability measure (DAM). The subjective scores have been examined to pinpoint the fidelity with which distinctive phonetic features are transmitted, and important quality attributes are preserved. Results show that a BBC at 9.6 kb/s, incorporating a suitable error correcting scheme, provides a moderately good quality, while the LPC at 2.4 kb/s yields a quality that is not felt to be commercially acceptable.

  17. Design of a Mobile Agent-Based Adaptive Communication Middleware for Federations of Critical Infrastructure Simulations

    NASA Astrophysics Data System (ADS)

    Görbil, Gökçe; Gelenbe, Erol

    The simulation of critical infrastructures (CI) can involve the use of diverse domain specific simulators that run on geographically distant sites. These diverse simulators must then be coordinated to run concurrently in order to evaluate the performance of critical infrastructures which influence each other, especially in emergency or resource-critical situations. We therefore describe the design of an adaptive communication middleware that provides reliable and real-time one-to-one and group communications for federations of CI simulators over a wide-area network (WAN). The proposed middleware is composed of mobile agent-based peer-to-peer (P2P) overlays, called virtual networks (VNets), to enable resilient, adaptive and real-time communications over unreliable and dynamic physical networks (PNets). The autonomous software agents comprising the communication middleware monitor their performance and the underlying PNet, and dynamically adapt the P2P overlay and migrate over the PNet in order to optimize communications according to the requirements of the federation and the current conditions of the PNet. Reliable communications is provided via redundancy within the communication middleware and intelligent migration of agents over the PNet. The proposed middleware integrates security methods in order to protect the communication infrastructure against attacks and provide privacy and anonymity to the participants of the federation. Experiments with an initial version of the communication middleware over a real-life networking testbed show that promising improvements can be obtained for unicast and group communications via the agent migration capability of our middleware.

  18. Design of an anti-Rician-fading modem for mobile satellite communication systems

    NASA Technical Reports Server (NTRS)

    Kojima, Toshiharu; Ishizu, Fumio; Miyake, Makoto; Murakami, Keishi; Fujino, Tadashi

    1995-01-01

    To design a demodulator applicable to mobile satellite communication systems using differential phase shift keying modulation, we have developed key technologies including an anti-Rician-fading demodulation scheme, an initial acquisition scheme, automatic gain control (AGC), automatic frequency control (AFC), and bit timing recovery (BTR). Using these technologies, we have developed one-chip digital signal processor (DSP) modem for mobile terminal, which is compact, of light weight, and of low power consumption. Results of performance test show that the developed DSP modem achieves good performance in terms of bit error ratio in mobile satellite communication environment, i.e., Rician fading channel. It is also shown that the initial acquisition scheme acquires received signal rapidly even if the carrier-to-noise power ratio (CNR) of the received signal is considerably low.

  19. A study and experiment plan for digital mobile communication via satellite

    NASA Technical Reports Server (NTRS)

    Jones, J. J.; Craighill, E. J.; Evans, R. G.; Vincze, A. D.; Tom, N. N.

    1978-01-01

    The viability of mobile communications is examined within the context of a frequency division multiple access, single channel per carrier satellite system emphasizing digital techniques to serve a large population of users. The intent is to provide the mobile users with a grade of service consistant with the requirements for remote, rural (perhaps emergency) voice communications, but which approaches toll quality speech. A traffic model is derived on which to base the determination of the required maximum number of satellite channels to provide the anticipated level of service. Various voice digitalization and digital modulation schemes are reviewed along with a general link analysis of the mobile system. Demand assignment multiple access considerations and analysis tradeoffs are presented. Finally, a completed configuration is described.

  20. MoM solutions to building blockage of mobile satellite communications

    NASA Astrophysics Data System (ADS)

    Salameh, M. S. H. Al; Mahmoud, S. A.-R. T.

    2011-12-01

    This article presents a full-wave propagation model for arbitrary profile of building blockage in mobile satellite communications, by solving the electric field integral equation for induced surface currents using the method of moments. Asymptotic expressions are used to simplify the integrals. Scattered fields are then found by the radiation equations derived from Maxwell equations. The total received fields around different profiles of buildings are calculated as a function of space, elevation angle and frequency. The results agree well with measurements and other published data. Various useful parameters for designing robust and reliable communication systems like frequency response, average fade duration and coherence bandwidth are found. Performance of mobile satellite system is evaluated in terms of bit error rate of mobile satellite system in frequency non-selective, slowly fading channel.

  1. Study of repeater technology for advanced multifunctional communications satellites

    NASA Technical Reports Server (NTRS)

    1972-01-01

    Investigations are presented concerning design concepts and implementation approaches for the satellite communication repeater subsystems of advanced multifunctional satellites. In such systems the important concepts are the use of multiple antenna beams, repeater switching (routing), and efficient spectrum utilization through frequency reuse. An information base on these techniques was developed and tradeoff analyses were made of repeater design concepts, with the work design taken in a broad sense to include modulation beam coverage patterns. There were five major areas of study: requirements analysis and processing; study of interbeam interference in multibeam systems; characterization of multiple-beam switching repeaters; estimation of repeater weight and power for a number of alternatives; and tradeoff analyses based on these weight and power data.

  2. Advanced information processing system: Inter-computer communication services

    NASA Technical Reports Server (NTRS)

    Burkhardt, Laura; Masotto, Tom; Sims, J. Terry; Whittredge, Roy; Alger, Linda S.

    1991-01-01

    The purpose is to document the functional requirements and detailed specifications for the Inter-Computer Communications Services (ICCS) of the Advanced Information Processing System (AIPS). An introductory section is provided to outline the overall architecture and functional requirements of the AIPS and to present an overview of the ICCS. An overview of the AIPS architecture as well as a brief description of the AIPS software is given. The guarantees of the ICCS are provided, and the ICCS is described as a seven-layered International Standards Organization (ISO) Model. The ICCS functional requirements, functional design, and detailed specifications as well as each layer of the ICCS are also described. A summary of results and suggestions for future work are presented.

  3. ACTS TDMA network control. [Advanced Communication Technology Satellite

    NASA Technical Reports Server (NTRS)

    Inukai, T.; Campanella, S. J.

    1984-01-01

    This paper presents basic network control concepts for the Advanced Communications Technology Satellite (ACTS) System. Two experimental systems, called the low-burst-rate and high-burst-rate systems, along with ACTS ground system features, are described. The network control issues addressed include frame structures, acquisition and synchronization procedures, coordinated station burst-time plan and satellite-time plan changes, on-board clock control based on ground drift measurements, rain fade control by means of adaptive forward-error-correction (FEC) coding and transmit power augmentation, and reassignment of channel capacities on demand. The NASA ground system, which includes a primary station, diversity station, and master control station, is also described.

  4. Experiments applications guide: Advanced Communications Technology Satellite (ACTS)

    NASA Technical Reports Server (NTRS)

    1988-01-01

    This applications guide first surveys the capabilities of the Advanced Communication Technology Satellite (ACTS) system (both the flight and ground segments). This overview is followed by a description of the baseband processor (BBP) and microwave switch matrix (MSM) operating modes. Terminals operating with the baseband processor are referred to as low burst rate (LBR); and those operating with the microwave switch matrix, as high burst rate (HBR). Three very small-aperture terminals (VSATs), LBR-1, LBR-2, and HBR, are described for various ACTS operating modes. Also described is the NASA Lewis link evaluation terminal. A section on ACTS experiment opportunities introduces a wide spectrum of network control, telecommunications, system, and scientific experiments. The performance of the VSATs is discussed in detail. This guide is intended as a catalyst to encourage participation by the telecommunications, business, and science communities in a broad spectrum of experiments.

  5. The Advanced Communications Technology Satellite - Performance, Reliability and Lessons Learned

    NASA Technical Reports Server (NTRS)

    Krawczyk, Richard J.; Ignaczak, Louis R.

    2000-01-01

    The Advanced Communications Satellite (ACTS) was conceived and developed in the mid- 1980s as an experimental satellite to demonstrate unproven Ka-band technology, and potential new commercial applications and services. Since launch into geostationary orbit in September 1993. ACTS has accumulated almost seven years of essentially trouble-free operation and met all program objectives. The unique technology, service experiments. and system level demonstrations accomplished by ACTS have been reported in many forums over the past several years. As ACTS completes its final experiments activity, this paper will relate the top-level program goals that have been achieved in the design, operation, and performance of the particular satellite subsystems. Pre-launch decisions to ensure satellite reliability and the subsequent operational experiences contribute to lessons learned that may be applicable to other comsat programs.

  6. NASA ACTS Multibeam Antenna (MBA) System. [Advanced Communications Technology Satellite

    NASA Technical Reports Server (NTRS)

    Choung, Youn H.; Stiles, W. Herschel; Wu, Joseph; Wong, William C.; Chen, C. Harry

    1986-01-01

    The design of the Advanced Communications Technology Satellite MBA system, which provides both spot beam and scanning beam coverage to both high and low burst rates data-users is examined. The MBA consists of receive and transmit antennas installed on a common precision mounting platform that is integrated to the bus through three flexures; a lightweight system with low thermal distortion is obtained by using composite materials for the MBA structures. The RF design, which is a Cassegrain reflector with a large equivalent focal length/aperture size, is described. Consideration is given to the position of the feed in order to minimize scan loss and sidelobe levels, the size of the subreflector in order to minimize feed spillover, and antenna performance degradation caused by reflector surface distortion. Breadbroad model test result reveal that the maximum sidelobe level outside the 2.5 HPBW region is -30 dB or lower relative to the power.

  7. iPads, mobile technologies, and communication applications: a survey of family wants, needs, and preferences.

    PubMed

    Meder, Allison M; Wegner, Jane R

    2015-03-01

    Families of children with communication disabilities were surveyed to explore wants and preferences relative to mobile media technology, including iPads, as a form of augmentative and alternative communication (AAC). The families surveyed reported wanting information and support from professionals, including speech language pathologists (SLPs), who are knowledgeable about AAC. These families wanted devices to meet their children's individual needs and reported that ease of use and affordability were the most influential characteristics in the purchase of mobile media devices and communication applications. SLPs who understand family decision making can utilize collaborative clinical decision making that respects families' wants and needs, while also focusing on device feature matching and family education. PMID:25685882

  8. Proceedings of the Advanced Communications Technology Satellite (ACTS) Conference 2000

    NASA Technical Reports Server (NTRS)

    Bauer, Robert (Editor); Derwae, Robert (Editor)

    2000-01-01

    The ACTS experiments program, which began in December 1993 and consisted of 103 different experiments, has made significant contributions to minimizing the risk of advanced satellite communications technology. The ACTS Conference 2000 (AC2000) was held to report the results of the program since the last ACTS conference was held in 1995 and to celebrate the end of a very successful satellite program. The conference was held on May 31, 2000, as part of the 6th Ka-band Utilization Conference in Cleveland, Ohio. Approximately 280 representatives of industry, academia, and government attended. The conference was organized into two parts: a technical session during the day and an evening reception. During the day, a series of five technical sessions included presentations of 17 papers covering the results of the experiment activity and technical performance of the satellite. In the evening, a reception was held to celebrate the end of the ACTS Experiments Program on one of NASA's most successful experimental communications satellite. These proceedings were developed to capture the entire event, including the evening reception.

  9. Innovative Networking Concepts Tested on the Advanced Communications Technology Satellite

    NASA Technical Reports Server (NTRS)

    Friedman, Daniel; Gupta, Sonjai; Zhang, Chuanguo; Ephremides, Anthony

    1996-01-01

    This paper describes a program of experiments conducted over the advanced communications technology satellite (ACTS) and the associated TI-VSAT (very small aperture terminal). The experiments were motivated by the commercial potential of low-cost receive only satellite terminals that can operate in a hybrid network environment, and by the desire to demonstrate frame relay technology over satellite networks. The first experiment tested highly adaptive methods of satellite bandwidth allocation in an integrated voice-data service environment. The second involved comparison of forward error correction (FEC) and automatic repeat request (ARQ) methods of error control for satellite communication with emphasis on the advantage that a hybrid architecture provides, especially in the case of multicasts. Finally, the third experiment demonstrated hybrid access to databases and compared the performance of internetworking protocols for interconnecting local area networks (LANs) via satellite. A custom unit termed frame relay access switch (FRACS) was developed by COMSAT Laboratories for these experiments; the preparation and conduct of these experiments involved a total of 20 people from the University of Maryland, the University of Colorado and COMSAT Laboratories, from late 1992 until 1995.

  10. Data communication requirements for the advanced NAS network

    NASA Technical Reports Server (NTRS)

    Levin, Eugene; Eaton, C. K.; Young, Bruce

    1986-01-01

    The goal of the Numerical Aerodynamic Simulation (NAS) Program is to provide a powerful computational environment for advanced research and development in aeronautics and related disciplines. The present NAS system consists of a Cray 2 supercomputer connected by a data network to a large mass storage system, to sophisticated local graphics workstations, and by remote communications to researchers throughout the United States. The program plan is to continue acquiring the most powerful supercomputers as they become available. In the 1987/1988 time period it is anticipated that a computer with 4 times the processing speed of a Cray 2 will be obtained and by 1990 an additional supercomputer with 16 times the speed of the Cray 2. The implications of this 20-fold increase in processing power on the data communications requirements are described. The analysis was based on models of the projected workload and system architecture. The results are presented together with the estimates of their sensitivity to assumptions inherent in the models.

  11. Patient–Clinician Mobile Communication: Analyzing Text Messaging Between Adolescents with Asthma and Nurse Case Managers

    PubMed Central

    Kim, Soo Yun; Hong, Yangsun; Chih, Ming-Yuan; Shah, Dhavan V.; Gustafson, David H.

    2015-01-01

    Abstract Background: With the increasing penetration of digital mobile devices among adolescents, mobile texting messaging is emerging as a new channel for patient–clinician communication for this population. In particular, it can promote active communication between healthcare clinicians and adolescents with asthma. However, little is known about the content of the messages exchanged in medical encounters via mobile text messaging. Therefore, this study explored the content of text messaging between clinicians and adolescents with asthma. Materials and Methods: We collected a total of 2,953 text messages exchanged between 5 nurse case managers and 131 adolescents with asthma through a personal digital assistant. The text messages were coded using a scheme developed by adapting categories from the Roter Interaction Analysis System. Results: Nurse case managers sent more text messages (n=2,639) than adolescents with asthma. Most messages sent by nurse case managers were targeted messages (n=2,475) directed at all adolescents with asthma, whereas there were relatively few tailored messages (n=164) that were created personally for an individual adolescent. In addition, both targeted and tailored messages emphasized task-focused behaviors over socioemotional behaviors. Likewise, text messages (n=314) sent by adolescents also emphasized task-focused over socioemotional behaviors. Conclusions: Mobile texting messaging has the potential to play an important role in patient–clinician communication. It promotes not only active interaction, but also patient-centered communication with clinicians. In order to achieve this potential, healthcare clinicians may need to focus on socioemotional communication as well as task-oriented communication. PMID:25401324

  12. Requirements for a mobile communications satellite system. Volume 2: Technical report

    NASA Technical Reports Server (NTRS)

    Horstein, M.

    1983-01-01

    Three types of satellite aided mobile communications are considered for users in areas not served by (terrestrial) cellular radio systems. In system 1, mobile units are provided a direct satellite link to a gateway station, which serves as the interface to the terrestrial toll network. In system 2, a terrestrial radio link similar to those in cellular systems connects the mobile unit to a translator station; each translator relays the traffic from mobile units in its vicinity, via satellite, to the regional gateway. It is not feasible for system 2 to provide obiquitous coverage. Therefore, system 3 is introduced, in which the small percentage of users not within range of a translator are provided a direct satellite link as in system 1.

  13. Prospects of satellite communications for mobiles: Towards a global mobile space segment

    NASA Astrophysics Data System (ADS)

    Rosetti, C.

    1981-11-01

    Terrestrial, maritime, and air transportation applications of communications satellites are considered. Communicating with long distance trucks can be achieved by text transmission which is cheaper than voice links, avoids access problems, and uses the frequency spectrum more efficiently. The need to accept fast and slow air traffic in the same air space, especially near airports, creates safety problems that can be overcome by equipping aircraft with a satellite controlled display device, showing traffic in the vicinity. The maritime satellite service is characterized by low market penetration that can be improved by cutting equipment costs, e.g., by decreasing ship antenna performance and using high gain satellite antennas, producing narrow beams.

  14. Advancing Higher Education with Mobile Learning Technologies: Cases, Trends, and Inquiry-Based Methods

    ERIC Educational Resources Information Center

    Keengwe, Jared, Ed.; Maxfield, Marian B., Ed.

    2015-01-01

    Rapid advancements in technology are creating new opportunities for educators to enhance their classroom techniques with digital learning resources. Once used solely outside of the classroom, smartphones, tablets, and e-readers are becoming common in many school settings. "Advancing Higher Education with Mobile Learning Technologies: Cases,…

  15. Patient-Provider Communications in Outpatient Clinic Settings: A Clinic-Based Evaluation of Mobile Device and Multimedia Mediated Communications for Patient Education

    PubMed Central

    Schooley, Benjamin; San Nicolas-Rocca, Tonia

    2015-01-01

    Background Many studies have provided evidence of the importance of quality provider-patient communications and have suggested improvements to patient understanding by using video-based instruction. Objective The objective of this study was to understand how mobile information technology assisted video and three-dimensional (3D) image instruction, provided by a health care worker, influences two categories of outcome: (1) patient understanding of information about their condition and detailed medical discharge instructions; and (2) patient perceptions and attitudes toward their health care providers, which included physicians, nurses, and staff. We hypothesize that video and 3D image instruction, provided on a mobile, tablet hardware platform, will improve patient understanding about the diagnostic testing, diagnoses, procedures, medications, and health topics provided to them. We also propose that use of the tablet/video combination will result in improved attitudinal evaluation by patients of their providers and the treatment plan. Methods This study evaluated a hospital clinic-based trial (patient N=284) of video and 3D image instruction, provided on a mobile, tablet hardware platform, and its potential to improve patient understanding about the diagnostic testing, diagnoses, procedures, medications, and health topics provided to them. Results Results showed strong evidence that the system was perceived as helpful for improving patient understanding, and that it improved communication between physicians and patients (P<.001). The advanced age of some patients had no effect on their perceptions of the tablet-based mediation. Physician comments provided useful insights on effective use of such systems in the future. Implications for further development and future research are discussed. Conclusions This study added to the body of evidence that computer-assisted video instructional systems for patients can improve patient understanding of medical instructions from

  16. Controlled mobility of unmanned aircraft chains to optimize network capacity in realistic communication environments

    NASA Astrophysics Data System (ADS)

    Dixon, Cory

    This dissertation presents a decentralized gradient-based mobility control algorithm for the formation and maintenance of an optimal end-to-end communication chain using a team of unmanned aircraft acting as communication relays. With the use of unmanned aircraft (UA) as communication relays, a common mode of operation is to form a communication relay chain between a lead exploring node (which may be ground based or another UA) and a control station. In this type of operation the lead node is typically deployed to explore (sense) a remote region of interest that is beyond direct radio frequency (RF) communication range, or out of line-of-sight, to the control station. To provide non-line-of-sight service, and extend the communication range of the lead node, unmanned aircraft acting as communication relays are deployed in a convoy fashion behind the lead vehicle to form a cascaded relay chain. The focus of this work is the use of the mobility of a fixed number of relay aircraft to maximize the capacity of a directed communication chain from a source node to a destination node. Local objective functions are presented that use the signal-to-noise-and-interference ratio (SNIR) of neighbor communication links as inputs to maximize the end-to-end capacity of packet-based and repeater-type network chains. An adaptive gradient-based SNIR controller using the local objective function can show significant improvement in the capacity of the communication chain that is not possible with range-based controllers, or static deployment strategies, in RF environments containing unknown localized noise sources and terrain effects. Since the SNIR field is unknown, an online estimate of the SNIR field gradient is formed using methods of Stochastic Approximation from the orbital motion of the aircraft tracking a control point. Flight demonstrations using the Networked Unmanned Aircraft System Command, Control and Communications testbed were conducted to validate the controller

  17. Towards Efficient Mobile M2M Communications: Survey and Open Challenges

    PubMed Central

    Pereira, Carlos; Aguiar, Ana

    2014-01-01

    Machine-to-Machine (M2M) communications enable networked devices and services to exchange information and perform actions seamlessly without the need for human intervention. They are viewed as a key enabler of the Internet of Things (IoT) and ubiquitous applications, like mobile healthcare, telemetry, or intelligent transport systems. We survey existing work on mobile M2M communications, we identify open challenges that have a direct impact on performance and resource usage efficiency, especially the impact on energy efficiency, and we review techniques to improve communications. We review the ETSI standard and application protocols, and draw considerations on the impact of their use in constrained mobile devices. Nowadays, smartphones are equipped with a wide range of embedded sensors, with varied local and wide area connectivity capabilities, and thus they offer a unique opportunity to serve as mobile gateways for other more constrained devices with local connectivity. At the same time, they can gather context data about users and environment from the embedded sensors. These capabilities may be crucial for mobile M2M applications. Finally, in this paper, we consider a scenario where smartphones are used as gateways that collect and aggregate data from sensors in a cellular network. We conclude that, in order for their use to the feasible in terms of a normal depletion time of a smartphone's battery, it is a good advice to maximize the collection of data necessary to be transmitted from nearby sensors, and maximize the intervals between transmissions. More research is required to devise energy efficient transmission methods that enable the use of smartphones as mobile gateways. PMID:25333291

  18. Towards efficient mobile M2M communications: survey and open challenges.

    PubMed

    Pereira, Carlos; Aguiar, Ana

    2014-01-01

    Machine-to-Machine (M2M) communications enable networked devices and services to exchange information and perform actions seamlessly without the need for human intervention. They are viewed as a key enabler of the Internet of Things (IoT) and ubiquitous applications, like mobile healthcare, telemetry, or intelligent transport systems. We survey existing work on mobile M2M communications, we identify open challenges that have a direct impact on performance and resource usage efficiency, especially the impact on energy efficiency, and we review techniques to improve communications. We review the ETSI standard and application protocols, and draw considerations on the impact of their use in constrained mobile devices. Nowadays, smartphones are equipped with a wide range of embedded sensors, with varied local and wide area connectivity capabilities, and thus they offer a unique opportunity to serve as mobile gateways for other more constrained devices with local connectivity. At the same time, they can gather context data about users and environment from the embedded sensors. These capabilities may be crucial for mobile M2M applications. Finally, in this paper, we consider a scenario where smartphones are used as gateways that collect and aggregate data from sensors in a cellular network. We conclude that, in order for their use to the feasible in terms of a normal depletion time of a smartphone's battery, it is a good advice to maximize the collection of data necessary to be transmitted from nearby sensors, and maximize the intervals between transmissions. More research is required to devise energy efficient transmission methods that enable the use of smartphones as mobile gateways. PMID:25333291

  19. Voice over IP: how computing technology is being used in mobile communications.

    PubMed

    Johnson, William

    2005-01-01

    This article explains how computing technology was used to address the need for mobile communications among nursing staff. In 2004, nursing staff at Fauquier Hospital relocated from one nursing floor in an older building to two floors in a new structure. This resulted in complaints and supervision issues as nursing managers, who had previously been relatively sedentary, now became quite mobile as they attempted to control nursing operations on two separate floors. Complaints arose from several sources. Nursing staff and managers both complained about the increased difficulty in communicating with each other Physicians expressed frustration to hospital administration at playing "telephone tag" with managers. The solution involved Internet Protocol technology that is in widespread use on most computer networks. The article details how this technology was selected over several other communications technologies and used to implement wireless telephony over the hospital's existing computer network. It reviews key standards and technologies and issues surrounding their use. Finally, the article demonstrates how this computing technology improved patient care by facilitating mobile communications. PMID:16266029

  20. Land mobile satellite communication system. Volume 3: Annexes to volume 2: Particular aspects of market analyses

    NASA Astrophysics Data System (ADS)

    Carnebianca, C.; Pavesi, B.; Tuozzi, A.; Capone, R.

    1986-06-01

    The socioeconomic desirability in terms of market demand, technical economic feasibility, and price-performance for a Land Mobile Communication system ground based and/or satellite aided, able to satisfy the request of the traffic demand, foreseeable in the 1995 to 2005 time frame, for the Western European countries was assessed. The criterion of economic value of the mobile system is considered as the driving element. Data on traffic; socioeconomic factors; economic factors; and radiotelephony, paging, and dispatch subscription and value for money trends are presented.

  1. Maintaining communication link based on AODV routing protocol in mobile robot networks

    NASA Astrophysics Data System (ADS)

    Hu, Hui; Jiang, Hong

    2007-12-01

    Wired computer networks are vital in modern life. However, these networks are extremely vulnerable to disaster or attack in emergency situations. Therefore, how to maintain communication link under emergency situations is very important. In this paper, we utilize a series of autonomous mobile slave robots which follow behind the lead robot and automatically stop where needed to maintain an ad hoc network for guaranteeing a link between the lead robot and its remote monitor/control station. To accomplish this target, an efficient communication protocol limitation mobile robots broadcast based on AODV (LMRB-AODV) is proposed for deployment in multi-robot system. After then the lead robot could carry service traffics to the monitor station under emergency situations through the communication link. At any instance, the lead robot has the ability to reclaim the relay robot(s) which are unneeded in the network to rejoin the convoy behind the lead robot and use it to extend the range of wireless communication when the radio frequency (RF) shortcuts are detected by the lead robot. All relay deployment and reclaiming strategy functions occur without the operator's involvement. Finally, we provide a comparative study of their performance in a number of different simulation environments. The results show that the proposed scheme is very efficient in maintaining communication link in wireless network.

  2. Trellis coding with Continuous Phase Modulation (CPM) for satellite-based land-mobile communications

    NASA Technical Reports Server (NTRS)

    1989-01-01

    This volume of the final report summarizes the results of our studies on the satellite-based mobile communications project. It includes: a detailed analysis, design, and simulations of trellis coded, full/partial response CPM signals with/without interleaving over various Rician fading channels; analysis and simulation of computational cutoff rates for coherent, noncoherent, and differential detection of CPM signals; optimization of the complete transmission system; analysis and simulation of power spectrum of the CPM signals; design and development of a class of Doppler frequency shift estimators; design and development of a symbol timing recovery circuit; and breadboard implementation of the transmission system. Studies prove the suitability of the CPM system for mobile communications.

  3. Modular, Cost-Effective, Extensible Avionics Architecture for Secure, Mobile Communications

    NASA Technical Reports Server (NTRS)

    Ivancic, William D.

    2007-01-01

    Current onboard communication architectures are based upon an all-in-one communications management unit. This unit and associated radio systems has regularly been designed as a one-off, proprietary system. As such, it lacks flexibility and cannot adapt easily to new technology, new communication protocols, and new communication links. This paper describes the current avionics communication architecture and provides a historical perspective of the evolution of this system. A new onboard architecture is proposed that allows full use of commercial-off-the-shelf technologies to be integrated in a modular approach thereby enabling a flexible, cost-effective and fully deployable design that can take advantage of ongoing advances in the computer, cryptography, and telecommunications industries.

  4. Modular, Cost-Effective, Extensible Avionics Architecture for Secure, Mobile Communications

    NASA Technical Reports Server (NTRS)

    Ivancic, William D.

    2006-01-01

    Current onboard communication architectures are based upon an all-in-one communications management unit. This unit and associated radio systems has regularly been designed as a one-off, proprietary system. As such, it lacks flexibility and cannot adapt easily to new technology, new communication protocols, and new communication links. This paper describes the current avionics communication architecture and provides a historical perspective of the evolution of this system. A new onboard architecture is proposed that allows full use of commercial-off-the-shelf technologies to be integrated in a modular approach thereby enabling a flexible, cost-effective and fully deployable design that can take advantage of ongoing advances in the computer, cryptography, and telecommunications industries.

  5. Integration of a Communicating Science Module into an Advanced Chemistry Laboratory Course

    ERIC Educational Resources Information Center

    Renaud, Jessica; Squier, Christopher; Larsen, Sarah C.

    2006-01-01

    A communicating science module was introduced into an advanced undergraduate physical chemistry laboratory course. The module was integrated into the course such that students received formal instruction in communicating science interwoven with the chemistry laboratory curriculum. The content of the communicating science module included three…

  6. Gigabit Satellite Network for NASA's Advanced Communication Technology Satellite (ACTS)

    NASA Technical Reports Server (NTRS)

    Hoder, Douglas; Bergamo, Marcos

    1996-01-01

    The advanced communication technology satellite (ACTS) gigabit satellite network provides long-haul point-to-point and point-to-multipoint full-duplex SONET services over NASA's ACTS. at rates up to 622 Mbit/s (SONET OC-12), with signal quality comparable to that obtained with terrestrial fiber networks. Data multiplexing over the satellite is accomplished using time-division multiple access (TDMA) techniques coordinated with the switching and beam hopping facilities provided by ACTS. Transmissions through the satellite are protected with Reed-Solomon encoding. providing virtually error-free transmission under most weather conditions. Unique to the system are a TDMA frame structure and satellite synchronization mechanism that allow: (a) very efficient utilization of the satellite capacity: (b) over-the-satellite dosed-loop synchronization of the network in configurations with up to 64 ground stations: and (c) ground station initial acquisition without collisions with existing signalling or data traffic. The user interfaces are compatible with SONET standards, performing the function of conventional SONET multiplexers and. as such. can be: readily integrated with standard SONET fiber-based terrestrial networks. Management of the network is based upon the simple network management protocol (SNMP). and includes an over-the-satellite signalling network and backup terrestrial internet (IP-based) connectivity. A description of the ground stations is also included.

  7. Imaging for understanding speech communication: Advances and challenges

    NASA Astrophysics Data System (ADS)

    Narayanan, Shrikanth

    2005-04-01

    Research in speech communication has relied on a variety of instrumentation methods to illuminate details of speech production and perception. One longstanding challenge has been the ability to examine real-time changes in the shaping of the vocal tract; a goal that has been furthered by imaging techniques such as ultrasound, movement tracking, and magnetic resonance imaging. The spatial and temporal resolution afforded by these techniques, however, has limited the scope of the investigations that could be carried out. In this talk, we focus on some recent advances in magnetic resonance imaging that allow us to perform near real-time investigations on the dynamics of vocal tract shaping during speech. Examples include Demolin et al. (2000) (4-5 images/second, ultra-fast turbo spin echo) and Mady et al. (2001,2002) (8 images/second, T1 fast gradient echo). A recent study by Narayanan et al. (2004) that used a spiral readout scheme to accelerate image acquisition has allowed for image reconstruction rates of 24 images/second. While these developments offer exciting prospects, a number of challenges lie ahead, including: (1) improving image acquisition protocols, hardware for enhancing signal-to-noise ratio, and optimizing spatial sampling; (2) acquiring quality synchronized audio; and (3) analyzing and modeling image data including cross-modality registration. [Work supported by NIH and NSF.

  8. Advanced Electrical, Optical and Data Communication Infrastructure Development

    SciTech Connect

    Simon Cobb

    2011-04-30

    The implementation of electrical and IT infrastructure systems at the North Carolina Center for Automotive Research , Inc. (NCCAR) has achieved several key objectives in terms of system functionality, operational safety and potential for ongoing research and development. Key conclusions include: (1) The proven ability to operate a high speed wireless data network over a large 155 acre area; (2) Node to node wireless transfers from access points are possible at speeds of more than 50 mph while maintaining high volume bandwidth; (3) Triangulation of electronic devices/users is possible in areas with overlapping multiple access points, outdoor areas with reduced overlap of access point coverage considerably reduces triangulation accuracy; (4) Wireless networks can be adversely affected by tree foliage, pine needles are a particular challenge due to the needle length relative to the transmission frequency/wavelength; and (5) Future research will use the project video surveillance and wireless systems to further develop automated image tracking functionality for the benefit of advanced vehicle safety monitoring and autonomous vehicle control through 'vehicle-to-vehicle' and 'vehicle-to-infrastructure' communications. A specific advantage realized from this IT implementation at NCCAR is that NC State University is implementing a similar wireless network across Centennial Campus, Raleigh, NC in 2011 and has benefited from lessons learned during this project. Consequently, students, researchers and members of the public will be able to benefit from a large scale IT implementation with features and improvements derived from this NCCAR project.

  9. AFFECTS - Advanced Forecast For Ensuring Communications Through Space

    NASA Astrophysics Data System (ADS)

    Bothmer, Volker

    2013-04-01

    Through the AFFECTS project funded by the European Union's 7th Framework Programme, European and US scientists develop an advanced proto-type space weather warning system to safeguard the operation of telecommunication and navigation systems on Earth to the threat of solar storms. The project is led by the University of Göttingen's Institute for Astrophysics and comprises worldwide leading research and academic institutions and industrial enterprises from Germany, Belgium, Ukraine, Norway and the United States. The key objectives of the AFFECTS project are: State-of-the-art analysis and modelling of the Sun-Earth chain of effects on the Earth's ionosphere and their subsequent impacts on communication systems based on multipoint space observations and complementary ground-based data. Development of a prototype space weather early warning system and reliable space weather forecasts, with specific emphasis on ionospheric applications. Dissemination of new space weather products and services to end users, the scientific community and general public. The presentation summarizes the project highlights, with special emphasis on the developed space weather forecast tools.

  10. A new blind nulling algorithm for CDMA mobile satellite communication systems

    NASA Astrophysics Data System (ADS)

    Liu, Yunzhi; Wang, Huali; Wang, Zhihui

    2007-11-01

    A new anti-jamming method is proposed combining adaptive array with direct sequence spread spectrum (DSSS) techniques in mobile satellite communication system. Different with the conventional depreading process, the proposed method modifies DSSS despreador, in which the output data are blindly processed. It overcomes the problem that DSSS signal often has very lower SNR, which is difficult to be captured in constant modulus array processing, especially when strong interference/jamming signals exist coincidentally.

  11. The technical and economic considerations of bringing satellite communications to small mobile users

    NASA Astrophysics Data System (ADS)

    Anson, P.; Crompton, E. K.

    1984-05-01

    The potential market presented by small users is considered and the characteristics of the present systems of communication satellites are reviewed. The satellite parameters of antenna gain and directivity and of bandwidth are then discussed and the operational considerations of the existing satellites are examined with reference to the requirements of the proposed small mobile users. The implications of economic tariffs are briefly touched upon.

  12. R&D on wireless broadband communication systems: new generation ubiquitous mobile network

    NASA Astrophysics Data System (ADS)

    Ogawa, Hiroyo

    2007-09-01

    R&D on new generation mobile network has attracted a growing interest over the world on the background of rapid market growth for 2nd and 3rd - generation cellular networks and wireless LANs/MANs. The National Institute of Information and Communications Technology (NICT) has been carried out the New Generation Mobile Network Project from April 2002 to March 2006, and has developed fundamental technologies to enable seamless and secure integration of various wireless access networks such as existing cellular networks, wireless LANs, home networks, intelligent transport systems (ITS), the Beyond-3G (B3G) cellular and other wireless access systems. From April 2006, Ubiquitous Mobile Network project focused on cognitive radio technology and integrated seamless networking technology was started. This paper overviews the achievement and the future plan of these projects.

  13. A description of QUALCOMM Automatic Satellite Position Reporting (QASPR(R)) for mobile communications

    NASA Technical Reports Server (NTRS)

    Ames, William G.

    1990-01-01

    Two satellite position reporting has been introduced into the OmniTRACS mobile satellite communication system. This system significantly improves position reporting reliability and accuracy while simplifying the terminal's hardware. The positioning technique uses the original OmniTRACS TDMA timing signal formats in the forward and return link directions plus an auxiliary, low power forward link signal through a second satellite to derive distance values. The distances are then converted into the mobile terminal's latitude and longitude in real time. A minor augmentation of the spread spectrum profile of the return link allowed the resolution of periodic ambiguities. The system also locates the two satellites in real time with fixed platforms in known locations using identical mobile terminal hardware. Initial accuracies of 1/4 mile have been realized uniformly throughout the USA using a satellite separation of 22 degrees and there are no dead zones, skywaves, or cycle slips as found in terrestrial systems like LORAN-C.

  14. Advanced multiple access concepts in mobile satellite systems

    NASA Technical Reports Server (NTRS)

    Ananasso, Fulvio

    1990-01-01

    Some multiple access strategies for Mobile Satellite Systems (MSS) are discussed. These strategies were investigated in the context of three separate studies conducted for the International Maritime Satellite Organization (INMARSAT) and the European Space Agency (ESA). Satellite-Switched Frequency Division Multiple Access (SS-FDMA), Code Division Multiple Access (CDMA), and Frequency-Addressable Beam architectures are addressed, discussing both system and technology aspects and outlining advantages and drawbacks of either solution with associated relevant hardware issues. An attempt is made to compare the considered option from the standpoint of user terminal/space segment complexity, synchronization requirements, spectral efficiency, and interference rejection.

  15. Satellite-aided mobile communications limited operational test in the trucking industry

    NASA Technical Reports Server (NTRS)

    Anderson, R. E.; Frey, R. L.; Lewis, J. R.

    1980-01-01

    An experiment with NASA's ATS-6 satellite, that demonstrates the practicality of satellite-aided land mobile communications is described. Satellite communications equipment for the experiment was designed so that it would be no more expensive, when mass produced, than conventional two-way mobile radio equipment. It embodied the operational features and convenience of present day mobile radios. Vehicle antennas 75 cm tall and 2 cm in diameter provided good commercial quality signals to and from trucks and jeeps. Operational applicability and usage data were gathered by installing the radio equipment in five long-haul tractor-trailer trucks and two Air Force search and rescue jeeps. Channel occupancy rates are reported. Air Force personnel found the satellite radio system extremely valuable in their search and rescue mission during maneuvers and actual rescue operations. Propagation data is subjectively analyzed and over 4 hours of random data is categorized and graded as to signal quality on a second by second basis. Trends in different topographic regions are reported. An overall communications reliability of 93% was observed despite low satellite elevation angles ranging from 9 to 24 degrees.

  16. Investigating the Impact of Personality Factors on Perceived Communication Mobility of Non-Native English Speaking Thai Professionals in International Companies

    ERIC Educational Resources Information Center

    Marina, Olga A.; Rajprasit, Krich

    2014-01-01

    Communication mobility has been suggested as an element of the complex construct of professional communicative competence, with a shared core of English in the oral mode, for professional international communication. This study aims (1) to investigate the possible correlation between the perceived level of communication mobility, and the influence…

  17. An overview of the technical design of MSAT mobile satellite communications services

    NASA Astrophysics Data System (ADS)

    Davies, N. George

    The Canadian MSAT mobile satellite communications system is being implemented in cooperation with the American Mobile Satellite Consortium (AMSC). Two satellites are to be jointly acquired and each satellite is expected to backup the other. This paper describes the technical concepts of the services to be offered and the baseline planning of the infrastructure for the ground segment. MSAT service requirements are analyzed for mobile radio, telephone, data, and aeronautical services. The MSAT system will use nine beams in a narrow range of L-band frequencies with frequency reuse. Beams may be added to cover flight information areas in the Atlantic and Pacific oceans. The elements of the network architecture are: a network control centre, data hub stations, gateway stations, base stations, mobile terminals, and a signalling system to interconnect the elements of the system. The network control center will manage the network and allocate space segment capacity; data hub stations will support a switched packet mobile data service; the gateway stations will provide interconnection to the public telephone system and data networks; and the base stations will support private circuit switched voice and data services. Several alternative designs for the signalling system are described.

  18. Advanced Communications Technology Satellite (ACTS) Used for Inclined Orbit Operations

    NASA Technical Reports Server (NTRS)

    Bauer, Robert A.

    2000-01-01

    The Advanced Communications Technology Satellite (ACTS) is operated by the NASA Glenn Research Center at Lewis Field 24 hours a day, 7 days a week. ACTS, which was launched in September 1993, is in its 7th year of operations, far exceeding the system s planned 2 years of operations and 4 years of designed mission life. After 5 successful years of operating as a geostationary satellite, the spacecraft s North-South stationkeeping was discontinued in August 1998. The system is now operating in an inclined orbit that increases at a rate of 0.8 /yr. With only scarce fuel remaining, operating in this mode extends the usage of the still totally functional payload. Although tracking systems are now needed on the experimenter Earth stations, experiment operations have continued with very little disruption. This is the only known geosynchronous Ka-band (30/20 GHz) spot-beam satellite operating in an inclined orbit. The project began its transition from geostationary operations to inclined operations in August 1998. This did not interrupt operations and was transparent to the experimenters on the system. For the space segment, new daily procedures were implemented to maintain the pointing of the system s narrow 0.3 spot beams while the spacecraft drifts in the North-South direction. For the ground segment, modifications were designed, developed, and fielded for the three classes of experimenter Earth stations. With the next generation of commercial satellite systems still being developed, ACTS remains the only operational testbed for Ka-band geosynchronous satellite communications over the Western hemisphere. Since inclined orbit operations began, the ACTS experiments program has supported 43 investigations by industry, Government, and academic organizations, as well as four demonstrations. The project s goals for inclined-orbit operations now reflect a narrower focus in the types of experiments that will be done. In these days of "faster, better, cheaper," NASA is seeking

  19. Mobile and Traditional Modes of Communication Among Male Latino Farmworkers: Implications for Health Communication and Dissemination.

    PubMed

    Sandberg, Joanne C; Spears Johnson, Chaya R; Nguyen, Ha T; Talton, Jennifer W; Quandt, Sara A; Chen, Haiying; Summers, Phillip; Arcury, Thomas A

    2016-06-01

    This analysis describes (1) cell phone and smartphone ownership, (2) continuity of phone numbers, (3) use of specific technologies while inside and outside the U.S., and (4) perceived adequacy of specific formats to receive health research results among Latino farmworkers. Telecommunications questionnaires were administered to 165 and 102 farmworkers in North Carolina in 2012 and 2013, respectively. Univariate and bivariate analyses were completed. Increasing numbers of Latino farmworkers own cell phones and smartphones. Talk and text functions are used frequently. Relatively few farmworkers maintain consistent phone numbers. They prefer to receive study results through low technology formats. Strategies to use cell phones to improve health or to share research findings will face obstacles in this population. Public health officials who identify and implement effective strategies to overcome these barriers may be able to harness mobile technologies to address the needs of Latino farmworkers. PMID:26463228

  20. Mobile and traditional modes of communication among male Latino farmworkers: Implications for health communication and dissemination

    PubMed Central

    Sandberg, Joanne C.; Spears Johnson, Chaya R.; Nguyen, Ha T.; Talton, Jennifer W.; Quandt, Sara A.; Chen, Haiying; Summers, Phillip; Arcury, Thomas A.

    2016-01-01

    Objectives This analysis describes 1) cell phone and smartphone ownership, 2) continuity of phone numbers, 3) use of specific technologies while inside and outside the U.S., and 4) perceived adequacy of specific formats to receive health research results among Latino farmworkers. Methods Telecommunications questionnaires were administered to 165 and 102 farmworkers in North Carolina in 2012 and 2013, respectively. Univariate and bivariate analyses were completed. Results Increasing numbers of Latino farmworkers own cell phones and smartphones. Talk and text functions are used frequently. Relatively few farmworkers maintain consistent phone numbers. They prefer to receive study results through low technology formats. Conclusion Strategies to use cell phones to improve health or to share research findings will face obstacles in this population. Public health officials who identify and implement effective strategies to overcome these barriers may be able to harness mobile technologies to address the needs of Latino farmworkers. PMID:26463228

  1. Mobile Communication and Civil Society: Linking Patterns and Places of Use to Engagement with Others in Public

    ERIC Educational Resources Information Center

    Campbell, Scott W.; Kwak, Nojin

    2011-01-01

    This study examined whether and how mobile communication influences the extent to which one engages with new people in public settings. Contrary to our expectation, general use of the technology in public did not detract from conversing with strangers. Shifting focus from "where" one uses the mobile phone to "how" it is used, we found that uses…

  2. [Mobile hospital -real time mobile telehealthcare system with ultrasound and CT van using high-speed satellite communication-].

    PubMed

    Takizawa, Masaomi; Miyashita, Toyohisa; Murase, Sumio; Kanda, Hirohito; Karaki, Yoshiaki; Yagi, Kazuo; Ohue, Toru

    2003-01-01

    A real-time telescreening system is developed to detect early diseases for rural area residents using two types of mobile vans with a portable satellite station. The system consists of a satellite communication system with 1.5Mbps of the JCSAT-1B satellite, a spiral CT van, an ultrasound imaging van with two video conference system, a DICOM server and a multicast communication unit. The video image and examination image data are transmitted from the van to hospitals and the university simultaneously. Physician in the hospital observes and interprets exam images from the van and watches the video images of the position of ultrasound transducer on screenee in the van. After the observation images, physician explains a results of the examination by the video conference system. Seventy lung CT screening and 203 ultrasound screening were done from March to June 2002. The trial of this real time screening suggested that rural residents are given better healthcare without visit to the hospital. And it will open the gateway to reduce the medical cost and medical divide between city area and rural area. PMID:12832865

  3. Core Structure Elements Architectures to Facilitate Construction and Secure Interconnection of Mobile Services Frameworks and Advanced IAM Systems

    NASA Astrophysics Data System (ADS)

    Karantjias, Athanasios; Polemi, Nineta

    The impressing penetration rates of electronic and mobile networks provide the unique opportunity to organizations to provide advanced e/m-services, accelerating their entrance in the digital society, and strengthening their fundamental structure. Service Oriented Architectures (SOAs) is an acknowledged promising technology to overcome the complexity inherent to the communication among multiple e-business actors across organizational domains. Nevertheless, the need for more privacy-aware transactions raises specific challenges that SOAs need to address, including the problems of managing identities and ensuring privacy in the e/m-environment. This article presents a targeted, user-centric scalable and federated Identity Management System (IAM), calledSecIdAM, and a mobile framework for building privacy-aware, interoperable, and secure mobile applications with respect to the way that the trust relationship among the involved entities, users and SOAs, is established. Finally, it analyzes a user-transparent m-process for obtaining an authentication and authorization token, issued from the SecIdAM as integrated in the IST European programme SWEB for the public sector.

  4. Evaluation of pediatric manual wheelchair mobility using advanced biomechanical methods.

    PubMed

    Slavens, Brooke A; Schnorenberg, Alyssa J; Aurit, Christine M; Graf, Adam; Krzak, Joseph J; Reiners, Kathryn; Vogel, Lawrence C; Harris, Gerald F

    2015-01-01

    There is minimal research of upper extremity joint dynamics during pediatric wheelchair mobility despite the large number of children using manual wheelchairs. Special concern arises with the pediatric population, particularly in regard to the longer duration of wheelchair use, joint integrity, participation and community integration, and transitional care into adulthood. This study seeks to provide evaluation methods for characterizing the biomechanics of wheelchair use by children with spinal cord injury (SCI). Twelve subjects with SCI underwent motion analysis while they propelled their wheelchair at a self-selected speed and propulsion pattern. Upper extremity joint kinematics, forces, and moments were computed using inverse dynamics methods with our custom model. The glenohumeral joint displayed the largest average range of motion (ROM) at 47.1° in the sagittal plane and the largest average superiorly and anteriorly directed joint forces of 6.1% BW and 6.5% BW, respectively. The largest joint moments were 1.4% body weight times height (BW × H) of elbow flexion and 1.2% BW × H of glenohumeral joint extension. Pediatric manual wheelchair users demonstrating these high joint demands may be at risk for pain and upper limb injuries. These evaluation methods may be a useful tool for clinicians and therapists for pediatric wheelchair prescription and training. PMID:25802860

  5. Antennas Designed for Advanced Communications for Air Traffic Management (AC/ATM) Project

    NASA Technical Reports Server (NTRS)

    Zakrajsek, Robert J.

    2000-01-01

    The goal of the Advanced Communications for Air Traffic Management (AC/ATM) Project at the NASA Glenn Research Center at Lewis Field is to enable a communications infrastructure that provides the capacity, efficiency, and flexibility necessary to realize a mature free-flight environment. The technical thrust of the AC/ATM Project is targeted at the design, development, integration, test, and demonstration of enabling technologies for global broadband aeronautical communications. Since Ku-band facilities and equipment are readily available, one of the near-term demonstrations involves a link through a Kuband communications satellite. Two conformally mounted antennas will support the initial AC/ATM communications links. Both of these are steered electronically through monolithic microwave integrated circuit (MMIC) amplifiers and phase shifters. This link will be asymmetrical with the downlink to the aircraft (mobile vehicle) at a throughput rate of greater than 1.5 megabits per second (Mbps), whereas the throughput rate of the uplink from the aircraft will be greater than 100 kilobits per second (kbps). The data on the downlink can be narrow-band, wide-band, or a combination of both, depending on the requirements of the experiment. The AC/ATM project is purchasing a phased-array Ku-band transmitting antenna for the uplink from the test vehicle. Many Ku-band receiving antennas have been built, and one will be borrowed for a short time to perform the initial experiments at the NASA Glenn Research Center at Lewis Field. The Ku-band transmitting antenna is a 254-element MMIC phased-array antenna being built by Boeing Phantom Works. Each element can radiate 100 mW. The antenna is approximately 43-cm high by 24-cm wide by 3.3-cm thick. It can be steered beyond 60 from broadside. The beamwidth varies from 6 at broadside to 12 degrees at 60 degrees, which is typical of phased-array antennas. When the antenna is steered to 60 degrees, the beamwidth will illuminate

  6. Proceedings of the Fifth International Mobile Satellite Conference 1997

    NASA Technical Reports Server (NTRS)

    Jedrey, T. (Compiler); Rigley, J. (Compiler); Anderson, Louise (Editor)

    1997-01-01

    Satellite-based mobile communications systems provide voice and data communications to users over a vast geographic area. The users may communicate via mobile or hand-held terminals, which may also provide access to terrestrial communications services. While previous International Mobile Satellite Conferences have concentrated on technical advances and the increasing worldwide commercial activities, this conference focuses on the next generation of mobile satellite services. The approximately 80 papers included here cover sessions in the following areas: networking and protocols; code division multiple access technologies; demand, economics and technology issues; current and planned systems; propagation; terminal technology; modulation and coding advances; spacecraft technology; advanced systems; and applications and experiments.

  7. R&D of a Next Generation LEO System for Global Multimedia Mobile Satellite Communications

    NASA Astrophysics Data System (ADS)

    Morikawa, E.; Motoyoshi, S.; Koyama, Y.; Suzuki, R.; Yasuda, Y.

    2002-01-01

    Next-generation LEO System Research Center (NeLS) was formed in the end of 1997 as a research group under the Telecommunications Advancement Organization of Japan, in cooperation with the telecommunications operators, manufacturers, universities and governmental research organization. The aim of this project is to develop new technology for global multimedia mobile satellite communications services with a user data rate around 2Mbps for handy terminals. component of the IMT-2000, and the second generation of the big-LEO systems. In prosecuting this project, two-phase approach, phase 1 and phase 2, is considered. Phase 1 is the system definition and development of key technologies. In Phase 2, we plan to verify the developed technology in Phase 1 on space. From this year we shifted the stage to Phase 2, and are now developing the prototype of on-board communication systems for flight tests, which will be planed at around 2006. The satellite altitude is assumed to be 1200 km in order to reduce the number of satellites, to avoid the Van Allen radiation belts and to increase the minimum elevation angle. Ten of the circular orbits with 55 degree of inclination are selected to cover the earth surface from -70 to 70 degree in latitude. 12 satellites are positioned at regular intervals in each orbit. In this case, the minimum elevation angle from the user terminal can be keep more than 20 degree for the visibility of the satellite, and 15 degree for simultaneous visibility of two satellites. Then, NeLS Research Center was focusing on the development of key technologies as the phase 1 project. Four kinds of key technologies; DBF satellite antenna, optical inter-satellite link system, satellite network technology with on-board ATM switch and variable rate modulation were selected. Satellite Antenna Technology: Development of on-board direct radiating active phased array antenna with digital beam forming technology would be one of the most important breakthroughs for the

  8. Visible light communication using mobile-phone camera with data rate higher than frame rate.

    PubMed

    Chow, Chi-Wai; Chen, Chung-Yen; Chen, Shih-Hao

    2015-10-01

    Complementary Metal-Oxide-Semiconductor (CMOS) image sensors are widely used in mobile-phone and cameras. Hence, it is attractive if these image sensors can be used as the visible light communication (VLC) receivers (Rxs). However, using these CMOS image sensors are challenging. In this work, we propose and demonstrate a VLC link using mobile-phone camera with data rate higher than frame rate of the CMOS image sensor. We first discuss and analyze the features of using CMOS image sensor as VLC Rx, including the rolling shutter effect, overlapping of exposure time of each row of pixels, frame-to-frame processing time gap, and also the image sensor "blooming" effect. Then, we describe the procedure of synchronization and demodulation. This includes file format conversion, grayscale conversion, column matrix selection avoiding blooming, polynomial fitting for threshold location. Finally, the evaluation of bit-error-rate (BER) is performed satisfying the forward error correction (FEC) limit. PMID:26480122

  9. Interference Analysis Status and Plans for Aeronautical Mobile Airport Communications System (AeroMACS)

    NASA Technical Reports Server (NTRS)

    Kerczewski, Robert J.; Wilson, Jeffrey D.

    2010-01-01

    Interference issues related to the operation of an aeronautical mobile airport communications system (AeroMACS) in the C-Band (specifically 5091-5150 MHz) is being investigated. The issue of primary interest is co-channel interference from AeroMACS into mobile-satellite system (MSS) feeder uplinks. The effort is focusing on establishing practical limits on AeroMACS transmissions from airports so that the threshold of interference into MSS is not exceeded. The analyses are being performed with the software package Visualyse Professional, developed by Transfinite Systems Limited. Results with omni-directional antennas and plans to extend the models to represent AeroMACS more accurately will be presented. These models should enable realistic analyses of emerging AeroMACS designs to be developed from NASA Test Bed, RTCA 223, and European results.

  10. Performance of a low data rate speech codec for land-mobile satellite communications

    NASA Technical Reports Server (NTRS)

    Gersho, Allen; Jedrey, Thomas C.

    1990-01-01

    In an effort to foster the development of new technologies for the emerging land mobile satellite communications services, JPL funded two development contracts in 1984: one to the Univ. of Calif., Santa Barbara and the other to the Georgia Inst. of Technology, to develop algorithms and real time hardware for near toll quality speech compression at 4800 bits per second. Both universities have developed and delivered speech codecs to JPL, and the UCSB codec was extensively tested by JPL in a variety of experimental setups. The basic UCSB speech codec algorithms and the test results of the various experiments performed with this codec are presented.

  11. Advancing Pedagogical Content Knowledge in Communication: A Critical Inquiry into the Ideology of Communication Theory Textbooks.

    ERIC Educational Resources Information Center

    Bedner, Nelle

    A study sought to reveal the ideological structure shaping representations of communication theory in contemporary communication theory textbooks. The characteristics of five communication theory textbooks, including such areas as theory inclusion, theory constitution, and theory presentation, as well as disciplinary issues, the concept of theory…

  12. Channel and terminal description of the ACTS mobile terminal

    NASA Technical Reports Server (NTRS)

    Abbe, B. S.; Agan, M. J.; Girardey, C. C.; Jedrey, T. C.

    1993-01-01

    The Advanced Communications Technology Satellite (ACTS) Mobile Terminal (AMT) is a proof-of-concept K/Ka-band mobile satellite communications terminal under development by NASA at JPL. Currently the AMT is undergoing system integration and test in preparation for a July 1993 ACTS launch and the subsequent commencement of mobile experiments in the fall of 1993. The AMT objectives are presented followed by a discussion of the AMT communications channel and mobile terminal design and performance.

  13. Channel and terminal description of the ACTS mobile terminal

    NASA Technical Reports Server (NTRS)

    Abbe, B. S.; Agan, M. J.; Girardey, C. C.; Jedrey, T. C.

    1994-01-01

    The Advanced Communications Technology Satellite (ACTS) Mobile Terminal (AMT) is a proof-of-concept K/Ka-band mobile satellite communications terminal under development by NASA at JPL. Currently the AMT is undergoing systems integration and testing in preparation for a July 1993 ACTS launch and the subsequent commencement of mobile experiments in the fall of 1993. The AMT objectives are presented, followed by a discussion of the AMT communications channel and the mobile terminal's design and performance.

  14. Design of Radio Frequency Link in Automatic Test System for Multimode Mobile Communication Base Station

    NASA Astrophysics Data System (ADS)

    Zhang, Weipeng

    2015-12-01

    A modularized design for the radio frequency (RF) link in automatic test system of multimode mobile communication base station is presented, considering also the characteristics of wireless communication indices and composition of signals of base stations. The test link is divided into general module, time division duplex (TDD) module, module of spurious noise filter, module of downlink intermodulation, module of uplink intermodulation and uplink block module. The composition of modules and link functions are defined, and the interfaces of the general module and the module of spurious noise filter are described. Finally, the estimated gain budget of the test link is presented. It is verified by experiments that the system is reliable and the test efficiency is improved.

  15. Robust formation tracking control of mobile robots via one-to-one time-varying communication

    NASA Astrophysics Data System (ADS)

    Dasdemir, Janset; Loría, Antonio

    2014-09-01

    We solve the formation tracking control problem for mobile robots via linear control, under the assumption that each agent communicates only with one 'leader' robot and with one follower, hence forming a spanning-tree topology. We assume that the communication may be interrupted on intervals of time. As in the classical tracking control problem for non-holonomic systems, the swarm is driven by a fictitious robot which moves about freely and which is a leader to one robot only. Our control approach is decentralised and the control laws are linear with time-varying gains; in particular, this accounts for the case when position measurements may be lost over intervals of time. For both velocity-controlled and force-controlled systems, we establish uniform global exponential stability, hence consensus formation tracking, for the error system under a condition of persistency of excitation on the reference angular velocity of the virtual leader and on the control gains.

  16. Using a Communication Model to Collect Measurement Data through Mobile Devices

    PubMed Central

    Bravo, José; Villarreal, Vladimir; Hervás, Ramón; Urzaiz, Gabriel

    2012-01-01

    Wireless systems and services have undergone remarkable development since the first mobile phone system was introduced in the early 1980s. The use of sensors in an Ambient Intelligence approach is a great solution in a medical environment. We define a communication architecture to facilitate the information transfer between all connected devices. This model is based in layers to allow the collection of measurement data to be used in our framework monitoring architecture. An overlay-based solution is built between network elements in order to provide an efficient and highly functional communication platform that allows the connection of a wide variety of devices and technologies, and serves also to perform additional functions such as the possibility to perform some processing in the network that may help to improve overall performance. PMID:23012542

  17. An isoflux antenna for a low earth orbit satellite mobile communication system

    NASA Astrophysics Data System (ADS)

    Tsao, C.-H. A.; Jung, P.; Raguenet, G.

    1992-03-01

    In this paper a satellite antenna for a low earth orbit satellite mobile communication system is described. The proposed communication system employs TDD-FD-CDMA (time division duplexing-frequency division-code division multiple access) technique which imposes certain constraints on the antenna design. The antenna discussed in this paper employs six spot beams in conjunction with the CDMA technology to allow the frequency spectrum reuse. The antenna radiation pattern in each beam is shaped to compensate for the path loss differences caused by the slant range differences from the spacecraft to different points on earth. This design provides an isometric radiation flux density on earth within each beam to mitigate the potential near/far problems in a CDMA system. Additional constraints on the antenna design include low profile, light weight and easy deployment to meet the requirements of small satellite implementation of the system.

  18. A spread-spectrum modem using constant envelope BPSK for a mobile satellite communications terminal

    NASA Technical Reports Server (NTRS)

    Iizuka, N.; Yamashita, A.; Takenaka, S.; Morikawa, E.; Ikegami, T.

    1990-01-01

    This paper describes a 5-kilobit/s spread spectrum modem with a 1.275 mega-Hz chip rate for mobile satellite communications. We used a Viterbi decoder with a coding gain of 7.8 dB at a BER of 10(exp -5) to decrease the required receiver power. This reduces the cost of communication services. The spread spectrum technique makes the modem immune to terrestrial radio signals and keeps it from causing interference in terrestrial radio systems. A class C power amplifier reduces the modem's power consumption. To avoid nonlinear distortion caused by the amplifier, the envelope of the input signal is kept constant by adding quadrature channel signal to the BPSK signal. To simulate the worst case, we measured the modem's output spectrum using a limiting amplifier instead of the class C amplifier, and found that 99 percent of the spectral power was confined to the specified 2.55 mega-Hz bandwidth.

  19. Advanced S-Band studies using the TDRSS communications satellite

    NASA Technical Reports Server (NTRS)

    Jenkins, Jeffrey D.; Osborne, William P.; Fan, Yiping

    1994-01-01

    This report will describe the design, implementation, and results of a propagation experiment which used TDRSS to transmit spread signals at S-Band to an instrumented mobile receiver. The results consist of fade measurements and distribution functions in 21 environments across the Continental United States (CONUS). From these distribution functions, some idea may be gained about what system designers should expect for excess path loss in many mobile environments. Some of these results may be compared against similar measurements made with narrowband beacon measurements. Such comparisons provide insight into what gains the spread signaling system may or may not have in multipath and shadowing environments.

  20. Advanced information processing system: Authentication protocols for network communication

    NASA Technical Reports Server (NTRS)

    Harper, Richard E.; Adams, Stuart J.; Babikyan, Carol A.; Butler, Bryan P.; Clark, Anne L.; Lala, Jaynarayan H.

    1994-01-01

    In safety critical I/O and intercomputer communication networks, reliable message transmission is an important concern. Difficulties of communication and fault identification in networks arise primarily because the sender of a transmission cannot be identified with certainty, an intermediate node can corrupt a message without certainty of detection, and a babbling node cannot be identified and silenced without lengthy diagnosis and reconfiguration . Authentication protocols use digital signature techniques to verify the authenticity of messages with high probability. Such protocols appear to provide an efficient solution to many of these problems. The objective of this program is to develop, demonstrate, and evaluate intercomputer communication architectures which employ authentication. As a context for the evaluation, the authentication protocol-based communication concept was demonstrated under this program by hosting a real-time flight critical guidance, navigation and control algorithm on a distributed, heterogeneous, mixed redundancy system of workstations and embedded fault-tolerant computers.

  1. Towards Situation Driven Mobile Tutoring System for Learning Languages and Communication Skills: Application to Users with Specific Needs

    ERIC Educational Resources Information Center

    Khemaja, Maha; Taamallah, Aroua

    2016-01-01

    Current advances in portable devices and wireless technologies had drastically impacted mobile and pervasive computing development and use. Nowadays, mobile and or pervasive applications, are increasingly being used to support users' everyday activities. These apps either distributed or standalone are characterized by the variability of the…

  2. Interprofessional Communication of Clinicians Using a Mobile Phone App: A Randomized Crossover Trial Using Simulated Patients

    PubMed Central

    Johnston, Maximilian; Cookson, Natalie; King, Dominic; Arora, Sonal; Darzi, Ara

    2016-01-01

    Background Most hospitals use paging systems as the principal communication system, despite general dissatisfaction by end users. To this end, we developed an app-based communication system (called Hark) to facilitate and improve the quality of interpersonal communication. Objective The objectives of our study were (1) to assess the quality of information transfer using pager- and app-based (Hark) communication systems, (2) to determine whether using mobile phone apps for escalation of care results in additional delays in communication, and (3) to determine how end users perceive mobile phone apps as an alternative to pagers. Methods We recruited junior (postgraduate year 1 and 2) doctors and nurses from a range of specialties and randomly assigned them to 2 groups who used either a pager device or the mobile phone-based Hark app. We asked nurses to hand off simulated patients while doctors were asked to receive handoff information using these devices. The quality of information transfer, time taken to respond to messages, and users’ satisfaction with each device was recorded. Each participant used both devices with a 2-week washout period in between uses. Results We recruited 22 participants (13 nurses, 9 doctors). The quality of the referrals made by nurses was significantly better when using Hark (Hark median 118, range 100–121 versus pager median 77, range 39–104; P=.001). Doctors responded to messages using Hark more quickly than when responding to pagers, although this difference was not statistically significant (Hark mean 86.6 seconds, SD 96.2 versus pager mean 136.5 seconds, SD 201.0; P=.12). Users rated Hark as significantly better on 11 of the 18 criteria of an information transfer device (P<.05) These included “enhances interprofessional efficiency,” “results in less disturbance,” “performed desired functions reliably,” and “allows me to clearly transfer information.” Conclusions Hark improved the quality of transfer of information

  3. Description and performance of a digital mobile satellite terminal

    NASA Technical Reports Server (NTRS)

    Lay, N.; Jedrey, T.; Parkyn, J.; Divsalar, D.

    1990-01-01

    A major goal of the Mobile Satellite Experiment (MSAT-X) program at the Jet Propulsion Lab (JPL) is the development of an advanced digital terminal for use in land mobile satellite communication. The terminal has been developed to minimize the risk of applying advanced technologies to future commercial mobile satellite systems (MSS). Testing with existing L band satellites was performed in fixed, land mobile and aeronautical mobile environments. JPL's development and tests of its mobile terminal have demonstrated the viability of narrowband digital voice communications in a land mobile environment through geostationary satellites. This paper provides a consolidated description of the terminal architecture and the performance of its individual elements.

  4. ETS-VI flight model transponder system for experimental fixed and mobile multibeam satellite communications

    NASA Astrophysics Data System (ADS)

    Kihata, Yuichi; Tanaka, Masayoshi; Sakamoto, Hiroshi; Yamamoto, Kazuichi; Horikawa, Kohji; Araki, Katsuhiko

    Nippon Telegraph and Telephone Corporation (NTT) is making intensive efforts in the research and development of multibeam satellite communications systems and is planning to carry out flight verification of the transponder system and communication experiments using the Engineering Test Satellite-VI (ETS-VI). The on-board transponder system developed by NTT is composed of a Ka-band multibeam SS-Time Division Multiple Access (TDMA) communications transponder and an S-band multibeam mobile satellite communications transponder. Various new technologies have been developed for the ETS-VI's transponder system. Thus, the transponder system needs to be throroughly evaluated in order to confirm the validity of the newly developed technologies. This paper discusses a newly developed evaluation system to efficiently evaluate the transponder performance. This system is composed of software for analyzing transponder characteristics and a fully automatic checkout system. The transponder performance was evaluated by using the new evaluation system. From these evaluated results, it was verified that the newly-developed technologies satisfy the required performance and are suitable for use in on-board equipment.

  5. Statistically validated mobile communication networks: the evolution of motifs in European and Chinese data

    NASA Astrophysics Data System (ADS)

    Li, Ming-Xia; Palchykov, Vasyl; Jiang, Zhi-Qiang; Kaski, Kimmo; Kertész, János; Miccichè, Salvatore; Tumminello, Michele; Zhou, Wei-Xing; Mantegna, Rosario N.

    2014-08-01

    Big data open up unprecedented opportunities for investigating complex systems, including society. In particular, communication data serve as major sources for computational social sciences, but they have to be cleaned and filtered as they may contain spurious information due to recording errors as well as interactions, like commercial and marketing activities, not directly related to the social network. The network constructed from communication data can only be considered as a proxy for the network of social relationships. Here we apply a systematic method, based on multiple-hypothesis testing, to statistically validate the links and then construct the corresponding Bonferroni network, generalized to the directed case. We study two large datasets of mobile phone records, one from Europe and the other from China. For both datasets we compare the raw data networks with the corresponding Bonferroni networks and point out significant differences in the structures and in the basic network measures. We show evidence that the Bonferroni network provides a better proxy for the network of social interactions than the original one. Using the filtered networks, we investigated the statistics and temporal evolution of small directed 3-motifs and concluded that closed communication triads have a formation time scale, which is quite fast and typically intraday. We also find that open communication triads preferentially evolve into other open triads with a higher fraction of reciprocated calls. These stylized facts were observed for both datasets.

  6. Advanced communications technology satellite high burst rate link evaluation terminal communication protocol software user's guide, version 1.0

    NASA Technical Reports Server (NTRS)

    Reinhart, Richard C.

    1993-01-01

    The Communication Protocol Software was developed at the NASA Lewis Research Center to support the Advanced Communications Technology Satellite High Burst Rate Link Evaluation Terminal (ACTS HBR-LET). The HBR-LET is an experimenters terminal to communicate with the ACTS for various experiments by government, university, and industry agencies. The Communication Protocol Software is one segment of the Control and Performance Monitor (C&PM) Software system of the HBR-LET. The Communication Protocol Software allows users to control and configure the Intermediate Frequency Switch Matrix (IFSM) on board the ACTS to yield a desired path through the spacecraft payload. Besides IFSM control, the C&PM Software System is also responsible for instrument control during HBR-LET experiments, uplink power control of the HBR-LET to demonstrate power augmentation during signal fade events, and data display. The Communication Protocol Software User's Guide, Version 1.0 (NASA CR-189162) outlines the commands and procedures to install and operate the Communication Protocol Software. Configuration files used to control the IFSM, operator commands, and error recovery procedures are discussed. The Communication Protocol Software Maintenance Manual, Version 1.0 (NASA CR-189163, to be published) is a programmer's guide to the Communication Protocol Software. This manual details the current implementation of the software from a technical perspective. Included is an overview of the Communication Protocol Software, computer algorithms, format representations, and computer hardware configuration. The Communication Protocol Software Test Plan (NASA CR-189164, to be published) provides a step-by-step procedure to verify the operation of the software. Included in the Test Plan is command transmission, telemetry reception, error detection, and error recovery procedures.

  7. The complexity of social mobilization in health communication: top-down and bottom-up experiences in polio eradication.

    PubMed

    Obregón, Rafael; Waisbord, Silvio

    2010-01-01

    The Polio Eradication Initiative (PEI) has been one of the most ambitious global health efforts in recent times. Social mobilization (SM) has been a strategic component of the PEI. Yet, a close-up analysis of SM dynamics seems to be lacking in the health communication literature. We examine critical aspects of the PEI experience in an attempt to move from dominant informational perspectives to a focus on emerging challenges in polio eradication efforts and new levels of complexity to SM. We examine available literature on communication and public health, available data on SM experiences that support polio eradication in Africa and Asia, and field work conducted by the authors where polio eradication efforts are ongoing. Our analysis suggests that (1) SM should not be casually approached as a top-down informational strategy to advance pre-established health goals; (2) centralized strategies hardly amount to SM; and (3) hybrid options that combine both activist and pragmatic SM are concrete possibilities for global health initiatives. In the context of renewed global democratization and persistent conflicts rooted in ethnicity, religion, and economics, it cannot be assumed that communities will either diligently espouse global goals or necessarily oppose them. Communication and SM strategies should rely on a clear understanding of the motives and agendas of involved actors. Resistance or opposition are important analytical dimensions as they may uncover new opportunities for effective health interventions. Further studies using these perspectives should be a priority for global health programs, including studies of the trust level, or lack thereof, among social actors. PMID:20455165

  8. A New mHealth Communication Framework for Use in Wearable WBANs and Mobile Technologies

    PubMed Central

    Hamida, Sana Tmar-Ben; Hamida, Elyes Ben; Ahmed, Beena

    2015-01-01

    Driven by the development of biomedical sensors and the availability of high mobile bandwidth, mobile health (mHealth) systems are now offering a wider range of new services. This revolution makes the idea of in-home health monitoring practical and provides the opportunity for assessment in “real-world” environments producing more ecologically valid data. In the field of insomnia diagnosis, for example, it is now possible to offer patients wearable sleep monitoring systems which can be used in the comfort of their homes over long periods of time. The recorded data collected from body sensors can be sent to a remote clinical back-end system for analysis and assessment. Most of the research on sleep reported in the literature mainly looks into how to automate the analysis of the sleep data and does not address the problem of the efficient encoding and secure transmissions of the collected health data. This article reviews the key enabling communication technologies and research challenges for the design of efficient mHealth systems. An end-to-end mHealth system architecture enabling the remote assessment and monitoring of patient's sleep disorders is then proposed and described as a case study. Finally, various mHealth data serialization formats and machine-to-machine (M2M) communication protocols are evaluated and compared under realistic operating conditions. PMID:25654718

  9. The ELLIPSO (tm) system: Elliptical low orbits for mobile communications and other optimum system elements

    NASA Astrophysics Data System (ADS)

    Castiel, David

    1991-09-01

    On 5 Nov. 1990, Ellipsat filed with the FCC the first application to provide voice communication services via low earth orbiting (LEO) satellites. The proposed system, ELLIPSO, aims at achieving end-user costs comparable to those in the cellular industry. On 3 Jun. 1991 Ellipsat filed for the second complement of its system. Ellipsat was also the first company to propose combined position determination and mobile voice services via low-earth orbiting satellites. Ellipsat is still the only proponent of elliptical orbits for any commercial system in the United States. ELLIPSO uses a spectrum efficient combination of FDMA and CDMA techniques. Ellipsat's strategy is to tailor required capacity to user demand, reduce initial system costs and investment risks, and allow the provision of services at affordable end-user prices. ELLIPSO offers optimum features in all the components of its system, elliptical orbits, small satellites, integrated protocol and signalling system, integrated end-user electronics, novel marketing approach based on the cooperation with the tenets of mobile communications, end-user costs that are affordable, and a low risk approach as deployment is tailored to the growth of its customer base. The efficient design of the ELLIPSO constellation and system allows estimated end-user costs in the $.50 per minute range, five to six times less than any other system of comparable capability.

  10. The ELLIPSO (tm) system: Elliptical low orbits for mobile communications and other optimum system elements

    NASA Technical Reports Server (NTRS)

    Castiel, David

    1991-01-01

    On 5 Nov. 1990, Ellipsat filed with the FCC the first application to provide voice communication services via low earth orbiting (LEO) satellites. The proposed system, ELLIPSO, aims at achieving end-user costs comparable to those in the cellular industry. On 3 Jun. 1991 Ellipsat filed for the second complement of its system. Ellipsat was also the first company to propose combined position determination and mobile voice services via low-earth orbiting satellites. Ellipsat is still the only proponent of elliptical orbits for any commercial system in the United States. ELLIPSO uses a spectrum efficient combination of FDMA and CDMA techniques. Ellipsat's strategy is to tailor required capacity to user demand, reduce initial system costs and investment risks, and allow the provision of services at affordable end-user prices. ELLIPSO offers optimum features in all the components of its system, elliptical orbits, small satellites, integrated protocol and signalling system, integrated end-user electronics, novel marketing approach based on the cooperation with the tenets of mobile communications, end-user costs that are affordable, and a low risk approach as deployment is tailored to the growth of its customer base. The efficient design of the ELLIPSO constellation and system allows estimated end-user costs in the $.50 per minute range, five to six times less than any other system of comparable capability.

  11. Place-Based Attributes Predict Community Membership in a Mobile Phone Communication Network

    PubMed Central

    Caughlin, T. Trevor; Ruktanonchai, Nick; Acevedo, Miguel A.; Lopiano, Kenneth K.; Prosper, Olivia; Eagle, Nathan; Tatem, Andrew J.

    2013-01-01

    Social networks can be organized into communities of closely connected nodes, a property known as modularity. Because diseases, information, and behaviors spread faster within communities than between communities, understanding modularity has broad implications for public policy, epidemiology and the social sciences. Explanations for community formation in social networks often incorporate the attributes of individual people, such as gender, ethnicity or shared activities. High modularity is also a property of large-scale social networks, where each node represents a population of individuals at a location, such as call flow between mobile phone towers. However, whether or not place-based attributes, including land cover and economic activity, can predict community membership for network nodes in large-scale networks remains unknown. We describe the pattern of modularity in a mobile phone communication network in the Dominican Republic, and use a linear discriminant analysis (LDA) to determine whether geographic context can explain community membership. Our results demonstrate that place-based attributes, including sugar cane production, urbanization, distance to the nearest airport, and wealth, correctly predicted community membership for over 70% of mobile phone towers. We observed a strongly positive correlation (r = 0.97) between the modularity score and the predictive ability of the LDA, suggesting that place-based attributes can accurately represent the processes driving modularity. In the absence of social network data, the methods we present can be used to predict community membership over large scales using solely place-based attributes. PMID:23451034

  12. Structured P2P Overlay of Mobile Brokers for Realizing Publish/Subscribe Communication in VANET

    PubMed Central

    Pandey, Tulika; Garg, Deepak; Gore, Manoj Madhava

    2014-01-01

    Publish/subscribe communication paradigm provides asynchrony and decoupling, making it an elegant alternative for designing applications in distributed and dynamic environment such as vehicular ad hoc networks (VANETs). In this paradigm, the broker is the most important component that decouples other two components, namely, publisher and subscriber. Previous research efforts have either utilized the deployment of distributed brokers on stationary road side info-stations or have assigned the role of broker to any moving vehicle on ad hoc basis. In one approach, lots of preinstalled infrastructures are needed whereas, in another, the quality of service is not guaranteed due to unpredictable moving and stopping patterns of vehicles. In this paper, we present the architecture of distributed mobile brokers which are dynamically reconfigurable in the form of structured P2P overlay and act as rendezvous points for matching publications and subscriptions. We have taken city buses in urban settings to act as mobile brokers whereas other vehicles are considered to be in role of publishers and subscribers. These mobile brokers also assist in locating a vehicle for successful and timely transfer of notifications. We have performed an extensive simulation study to compare our approach with previously proposed approaches. Simulation results establish the applicability of our approach. PMID:24523629

  13. The land mobile satellite communication channel - Recording, statistics, and channel model

    NASA Astrophysics Data System (ADS)

    Lutz, Erich; Cygan, Daniel; Dippold, Michael; Dolainsky, Frank; Papke, Wolfgang

    1991-05-01

    The communication channel between the MARECS satellite at 26 deg W and a cruising van was measured and recorded in European areas exhibiting satellite elevations from 13 to 43 deg. Different environments and mobile antennas were tested. Results of an extensive statistical evaluation include spectra of the fading amplitude, probability density, and distribution of the received signal power as well as the percentage of time for fade and nonfade periods. Based on the physical phenomena of multipath fading and signal shadowing, an analog model of the land mobile satellite channel which can readily be used for software and hardware fading simulation is developed. The most important parameter of this model is the time-share of shadowing, A, ranging from less than 1 percent on southern highways to 89 percent in the city of Stockholm. The Rice factor, c, which characterizes the channel during unshadowed periods, can vary from 3.9 to 18.1 dB. For analytical purposes, the land mobile satellite channel can be represented by a digital two-state Gilbert-Elliott model. For DPSK (differential phase-shift keying) modulation with a 10-dB signal-to-noise ratio in the satellite link, the mean bit error probability in the unshadowed channel state is typically in the range of 0.0001-0.01, while it is around 0.3 in the shadowed channel state. With regard to data transmission, block error probability density, error gap distribution, and block error probability are discussed.

  14. Channel aware HARQ scheme based on LDPC codes for land mobile satellite communication system

    NASA Astrophysics Data System (ADS)

    Yang, Yongli; Zhu, Guangxi; Wang, Desheng; Wu, Lifen

    2007-11-01

    In this paper, a channel aware HARQ (CA-HARQ) scheme based on data punctured rate compatible LDPC (DP-LDPC) codes, which might satisfy the demand for bandwidth and rate in land mobile communication system, is proposed. The scheme is based on type II HARQ technique cooperated with a DP- LDPC code. In the proposed scheme, the effective rate of the LDPC code is adapted according to the channel quality information (CQI) estimated at the receiver, so as to decrease the redundancy when the channel is good and vice versa, the retransmitted blocks are combined with the previous information transmitted to achieve high probability of successful decoding. In this paper, we use a 2-bit CQI feedback scheme. Simulation results, which based on a land mobile satellite channel, show that the proposed channel aware H-ARQ scheme based on DP-LDPC codes improved the throughput by 0.4dB at low SNR compared to a pure DP-LDPC type II HARQ, and it can also be an effective solution to compensate rain attenuation and multipath fading in land mobile satellite systems.

  15. Place-based attributes predict community membership in a mobile phone communication network.

    PubMed

    Caughlin, T Trevor; Ruktanonchai, Nick; Acevedo, Miguel A; Lopiano, Kenneth K; Prosper, Olivia; Eagle, Nathan; Tatem, Andrew J

    2013-01-01

    Social networks can be organized into communities of closely connected nodes, a property known as modularity. Because diseases, information, and behaviors spread faster within communities than between communities, understanding modularity has broad implications for public policy, epidemiology and the social sciences. Explanations for community formation in social networks often incorporate the attributes of individual people, such as gender, ethnicity or shared activities. High modularity is also a property of large-scale social networks, where each node represents a population of individuals at a location, such as call flow between mobile phone towers. However, whether or not place-based attributes, including land cover and economic activity, can predict community membership for network nodes in large-scale networks remains unknown. We describe the pattern of modularity in a mobile phone communication network in the Dominican Republic, and use a linear discriminant analysis (LDA) to determine whether geographic context can explain community membership. Our results demonstrate that place-based attributes, including sugar cane production, urbanization, distance to the nearest airport, and wealth, correctly predicted community membership for over 70% of mobile phone towers. We observed a strongly positive correlation (r = 0.97) between the modularity score and the predictive ability of the LDA, suggesting that place-based attributes can accurately represent the processes driving modularity. In the absence of social network data, the methods we present can be used to predict community membership over large scales using solely place-based attributes. PMID:23451034

  16. Structured P2P overlay of mobile brokers for realizing publish/subscribe communication in VANET.

    PubMed

    Pandey, Tulika; Garg, Deepak; Gore, Manoj Madhava

    2014-01-01

    Publish/subscribe communication paradigm provides asynchrony and decoupling, making it an elegant alternative for designing applications in distributed and dynamic environment such as vehicular ad hoc networks (VANETs). In this paradigm, the broker is the most important component that decouples other two components, namely, publisher and subscriber. Previous research efforts have either utilized the deployment of distributed brokers on stationary road side info-stations or have assigned the role of broker to any moving vehicle on ad hoc basis. In one approach, lots of preinstalled infrastructures are needed whereas, in another, the quality of service is not guaranteed due to unpredictable moving and stopping patterns of vehicles. In this paper, we present the architecture of distributed mobile brokers which are dynamically reconfigurable in the form of structured P2P overlay and act as rendezvous points for matching publications and subscriptions. We have taken city buses in urban settings to act as mobile brokers whereas other vehicles are considered to be in role of publishers and subscribers. These mobile brokers also assist in locating a vehicle for successful and timely transfer of notifications. We have performed an extensive simulation study to compare our approach with previously proposed approaches. Simulation results establish the applicability of our approach. PMID:24523629

  17. Identifying Successful Advancement Approaches in Four Catholic Universities: The Effectiveness of the Four Advancement Models of Communication

    ERIC Educational Resources Information Center

    Bonglia, Jean-Pierre K.

    2010-01-01

    The current longitudinal study of the most successful Catholic universities in the United States identifies the prevalence of four advancement models of communication that have contributed to make those institutions successful in their philanthropic efforts. While research by Grunig and Kelly maintained that the two-way symmetrical model of…

  18. Classroom Communication and Instructional Processes: Advances through Meta-Analysis

    ERIC Educational Resources Information Center

    Gayle, Barbara Mae, Ed.; Preiss, Raymond W., Ed.; Burrell, Nancy, Ed.; Allen, Mike, Ed.

    2006-01-01

    This volume offers a systematic review of the literature on communication education and instruction. Making meta-analysis findings accessible and relevant, the editors of this volume approach the topic from the perspective that meta-analysis serves as a useful tool for summarizing experiments and for determining how and why specific teaching and…

  19. Development of a preprototype Advanced Extravehicular Mobility Unit (AEMU) regenerable life support subsystem - A progress report

    NASA Technical Reports Server (NTRS)

    Allen, Norman C.; Lawson, B. Michael

    1989-01-01

    Regenerable life support (RLS) technologies are being developed for use in the Advanced Extravehicle Mobility Unit (AEMU) aboard Space Station Freedom. This report describes the requirements that these RLS technologies must satisfy in the Space Station application and the significant features of the technologies now being evaluated. Who is developing the equipment and how the subsystems will be integrated are addressed. An overview of the planned test program schedule is given.

  20. Requirements for a mobile communications satellite system. Volume 1: Executive summary

    NASA Technical Reports Server (NTRS)

    1983-01-01

    Three types of satellite-aided mobile communications are considered for users in areas not served by (terrestrial) cellular radio systems. In System 1, mobile units are provided a direct satellite link to a gateway station, which serves as the interface to the terrestrial toll network. In System 2, a terrestrial radio link similar to those in cellular systems connects the mobile unit to a translator station; each translator relays the traffic from mobile units in its vicinity, via satellite, to the regional gateway. It is not feasible for System 2 to provide ubiquitous coverage. Therefore, System 3 is introduced, in which the small percentage of users not within range of a translator are provided a direct satellite link as in System 1. While System 2 can operate with leased satellite capacity, Systems 1 and 3 require a dedicated satellite. A major portion of this study is concerned with the design of a satellite for System 1. A weight limit of 10,000 lbs, corresponding to the projected 1990 STS capability, is imposed on the design. Frequency re-use of the allocated spectrum, through multiple satellite beams, is employed to generate the specified system capacity. Both offset-fed and center-fed reflectors are considered. For an assumed 10-MHz allocation and a population of 350,000 subscribers, a two-satellite system is required. The reflector diameters corresponding to offset-fed and center-fed geometries are 46 m and 62 m, respectively. Thus, large-space-structure technology is inherent to the implementation of System 1. In addition to establishing the technical requirements for the three types of satellite systems, the monthly service charge needed to provide a specified return on invested capital is computed. A net present value analysis is used for this purpose.

  1. Requirements for a mobile communications satellite system. Volume 1: Executive summary

    NASA Astrophysics Data System (ADS)

    1983-04-01

    Three types of satellite-aided mobile communications are considered for users in areas not served by (terrestrial) cellular radio systems. In System 1, mobile units are provided a direct satellite link to a gateway station, which serves as the interface to the terrestrial toll network. In System 2, a terrestrial radio link similar to those in cellular systems connects the mobile unit to a translator station; each translator relays the traffic from mobile units in its vicinity, via satellite, to the regional gateway. It is not feasible for System 2 to provide ubiquitous coverage. Therefore, System 3 is introduced, in which the small percentage of users not within range of a translator are provided a direct satellite link as in System 1. While System 2 can operate with leased satellite capacity, Systems 1 and 3 require a dedicated satellite. A major portion of this study is concerned with the design of a satellite for System 1. A weight limit of 10,000 lbs, corresponding to the projected 1990 STS capability, is imposed on the design. Frequency re-use of the allocated spectrum, through multiple satellite beams, is employed to generate the specified system capacity. Both offset-fed and center-fed reflectors are considered. For an assumed 10-MHz allocation and a population of 350,000 subscribers, a two-satellite system is required. The reflector diameters corresponding to offset-fed and center-fed geometries are 46 m and 62 m, respectively. Thus, large-space-structure technology is inherent to the implementation of System 1. In addition to establishing the technical requirements for the three types of satellite systems, the monthly service charge needed to provide a specified return on invested capital is computed. A net present value analysis is used for this purpose.

  2. Proceedings of the Twentieth NASA Propagation Experimenters Meeting (NAPEX XX) and the Advanced Communications Technology Satellite (ACTS) Propagation Studies Miniworkshop

    NASA Technical Reports Server (NTRS)

    Golshan, Nassar (Editor)

    1996-01-01

    The NASA Propagation Experimenters (NAPEX) Meeting and associated Advanced Communications Technology Satellite (ACTS) Propagation Studies Miniworkshop convene yearly to discuss studies supported by the NASA Propagation Program. Representatives from the satellite communications (satcom)industry, academia, and government with an interest in space-ground radio wave propagation have peer discussion of work in progress, disseminate propagation results, and interact with the satcom industry. NAPEX XX, in Fairbanks, Alaska, June 4-5, 1996, had three sessions: (1) "ACTS Propagation Study: Background, Objectives, and Outcomes," covered results from thirteen station-years of Ka-band experiments; (2) "Propagation Studies for Mobile and Personal Satellite Applications," provided the latest developments in measurement, modeling, and dissemination of propagation phenomena of interest to the mobile, personal, and aeronautical satcom industry; and (3)"Propagation Research Topics," covered a range of topics including space/ground optical propagation experiments, propagation databases, the NASA Propagation Web Site, and revision plans for the NASA propagation effects handbooks. The ACTS Miniworkshop, June 6, 1996, covered ACTS status, engineering support for ACTS propagation terminals, and the ACTS Propagation Data Center. A plenary session made specific recommendations for the future direction of the program.

  3. LTE-advanced random access mechanism for M2M communication: A review

    NASA Astrophysics Data System (ADS)

    Mustafa, Rashid; Sarowa, Sandeep; Jaglan, Reena Rathee; Khan, Mohammad Junaid; Agrawal, Sunil

    2016-03-01

    Machine Type Communications (MTC) enables one or more self-sufficient machines to communicate directly with one another without human interference. MTC applications include smart grid, security, e-Health and intelligent automation system. To support huge numbers of MTC devices, one of the challenging issues is to provide a competent way for numerous access in the network and to minimize network overload. In this article, the different control mechanisms for overload random access are reviewed to avoid congestion caused by random access channel (RACH) of MTC devices. However, past and present wireless technologies have been engineered for Human-to-Human (H2H) communications, in particular, for transmission of voice. Consequently the Long Term Evolution (LTE) -Advanced is expected to play a central role in communicating Machine to Machine (M2M) and are very optimistic about H2H communications. Distinct and unique characteristics of M2M communications create new challenges from those in H2H communications. In this article, we investigate the impact of massive M2M terminals attempting random access to LTE-Advanced all at once. We discuss and review the solutions to alleviate the overload problem by Third Generation Partnership Project (3GPP). As a result, we evaluate and compare these solutions that can effectively eliminate the congestion on the random access channel for M2M communications without affecting H2H communications.

  4. Communication, Interventions, and Scientific Advances in Autism: A Commentary

    PubMed Central

    Llaneza, Danielle C.; DeLuke, Susan V.; Batista, Myra; Crawley, Jacqueline N.; Christodulu, Kristin V.; Frye, Cheryl A.

    2010-01-01

    Autism spectrum disorders (ASD) affect approximately 1 in 150 children across the U.S., and are characterized by abnormal social actions, language difficulties, repetitive or restrictive behaviors, and special interests. ASD include autism (autistic disorder), Asperger syndrome, and Pervasive Developmental Disorder not otherwise specified (PDD-NOS or atypical autism). High-functioning individuals may communicate with moderate-to-high language skills, although difficulties in social skills may result in communication deficits. Low-functioning individuals may have severe deficiencies in language, resulting in poor communication between the individual and others. Behavioral intervention programs have been developed for ASD, and are frequently adjusted to accommodate specific individual needs. Many of these programs are school-based and aim to support the child in the development of their skills, for use outside the classroom with family and friends. Strides are being made in understanding the factors contributing to the development of ASD, particularly the genetic contributions that may underlie these disorders. Mutant mouse models provide powerful research tools to investigate the genetic factors associated with ASD and its co-morbid disorders. In support, the BTBR T+tf/J mouse strain incorporates ASD-like social and communication deficits and high levels of repetitive behaviors. This commentary briefly reviews the reciprocal relationship between observations made during evidence-based behavioral interventions of high- versus low-functioning children with ASD and the accumulating body of research in autism, including animal studies and basic research models. This reciprocity is one of the hallmarks of the scientific method, such that research may inform behavioral treatments, and observations made during treatment may inform subsequent research. PMID:20093134

  5. ICSW2AN : An Inter-vehicle Communication System Using Mobile Access Point over Wireless Wide Area Networks

    NASA Astrophysics Data System (ADS)

    Byun, Tae-Young

    This paper presents a prototype of inter-vehicle communication system using mobile access point that internetworks wired or wireless LAN and wireless WAN anywhere. Implemented mobile access point can be equipped with various wireless WAN interfaces such as WCDMA and HSDPA. Mobile access point in the IP mechanism has to process connection setup procedure to one wireless WAN. To show the applicability of the mobile access point to inter-vehicle communication, a simplified V2I2V-based car communication system called ICSW2AN is implemented to evaluate major performance metrics by road test. In addition, results of road test for traffic information service are investigated in view of RTT, latency and server processing time. The experimental result indicates that V2I2V-based car communication system sufficiently can provide time-tolerant traffic information to moving vehicles while more than two mobile devices in restricted spaces such as car, train and ship access wireless Internet simultaneously.

  6. ACTS mobile SATCOM experiments

    NASA Technical Reports Server (NTRS)

    Abbe, Brian S.; Frye, Robert E.; Jedrey, Thomas C.

    1993-01-01

    Over the last decade, the demand for reliable mobile satellite communications (satcom) for voice, data, and video applications has increased dramatically. As consumer demand grows, the current spectrum allocation at L-band could become saturated. For this reason, NASA and the Jet Propulsion Laboratory are developing the Advanced Communications Technology Satellites (ACTS) mobile terminal (AMT) and are evaluating the feasibility of K/Ka-band (20/30 GHz) mobile satcom to meet these growing needs. U.S. industry and government, acting as co-partners, will evaluate K/Ka-band mobile satcom and develop new technologies by conducting a series of applications-oriented experiments. The ACTS and the AMT testbed will be used to conduct these mobile satcom experiments. The goals of the ACTS Mobile Experiments Program and the individual experiment configurations and objectives are further presented.

  7. Modeling and Performance Analysis of an Improved Movement-Based Location Management Scheme for Packet-Switched Mobile Communication Systems

    PubMed Central

    Chung, Yun Won; Park, Suwon

    2014-01-01

    One of the key technologies to support mobility of mobile station (MS) in mobile communication systems is location management which consists of location update and paging. In this paper, an improved movement-based location management scheme with two movement thresholds is proposed, considering bursty data traffic characteristics of packet-switched (PS) services. The analytical modeling for location update and paging signaling loads of the proposed scheme is developed thoroughly and the performance of the proposed scheme is compared with that of the conventional scheme. We show that the proposed scheme outperforms the conventional scheme in terms of total signaling load with an appropriate selection of movement thresholds. PMID:24741363

  8. A systems approach to the commercialization of space communications technology - The NASA/JPL Mobile Satellite Program

    NASA Technical Reports Server (NTRS)

    Weber, William J., III; Gray, Valerie W.; Jackson, Byron; Steele, Laura C.

    1991-01-01

    This paper discusss the systems approach taken by NASA and the Jet Propulsion Laboratory in the commercialization of land-mobile satellite services (LMSS) in the United States. As the lead center for NASA's Mobile Satellite Program, JPL was involved in identifying and addressing many of the key barriers to commercialization of mobile satellite communications, including technical, economic, regulatory and institutional risks, or uncertainties. The systems engineering approach described here was used to mitigate these risks. The result was the development and implementation of the JPL Mobile Satellite Experiment Project. This Project included not only technology development, but also studies to support NASA in the definition of the regulatory, market, and investment environments within which LMSS would evolve and eventually operate, as well as initiatives to mitigate their associated commercialization risks. The end result of these government-led endeavors was the acceleration of the introduction of commercial mobile satellite services, both nationally and internationally.

  9. Proceedings of the Fourth International Mobile Satellite Conference (IMSC 1995)

    NASA Technical Reports Server (NTRS)

    Rigley, Jack R. (Compiler); Estabrook, Polly (Compiler); Reekie, D. Hugh M. (Editor)

    1995-01-01

    The theme to the 1995 International Mobile Satellite Conference was 'Mobile Satcom Comes of Age'. The sessions included Modulation, Coding, and Multiple Access; Hybrid Networks - 1; Spacecraft Technology; propagation; Applications and Experiments - 1; Advanced System Concepts and Analysis; Aeronautical Mobile Satellite Communications; Mobile Terminal Antennas; Mobile Terminal Technology; Current and Planned Systems; Direct Broadcast Satellite; The Use of CDMA for LEO and ICO Mobile Satellite Systems; Hybrid Networks - 2; and Applications and Experiments - 2.

  10. Peer influence on protest participation: Communication and trust between co-workers as inhibitors or facilitators of mobilization.

    PubMed

    Born, Marieke; Akkerman, Agnes; Thommes, Kirsten

    2016-03-01

    In this article, we investigate how communication and trust networks between employees affect participation in a strike. We analyze whether the strength of network relations is related to congruence in strike behavior using social network data on 59 Dutch workers. We find that private communication networks and trust networks lead to similar strike behavior. This finding indicates that networks not only promote protest mobilization but are also vehicles for demobilization, albeit through different network relations. PMID:26857172

  11. Path Loss Prediction Formula in Urban Area for the Fourth-Generation Mobile Communication Systems

    NASA Astrophysics Data System (ADS)

    Kitao, Koshiro; Ichitsubo, Shinichi

    A site-general type prediction formula is created based on the measurement results in an urban area in Japan assuming that the prediction frequency range required for Fourth-Generation (4G) Mobile Communication Systems is from 3 to 6GHz, the distance range is 0.1 to 3km, and the base station (BS) height range is from 10 to 100m. Based on the measurement results, the path loss (dB) is found to be proportional to the logarithm of the distance (m), the logarithm of the BS height (m), and the logarithm of the frequency (GHz). Furthermore, we examine the extension of existing formulae such as the Okumura-Hata, Walfisch-Ikegami, and Sakagami formulae for 4G systems and propose a prediction formula based on the Extended Sakagami formula.

  12. Concepts and cost trade-offs for land vehicle antennas in satellite mobile communications

    NASA Technical Reports Server (NTRS)

    Haddad, H. A.

    1948-01-01

    Several antenna design concepts, operating at UHF (821 to 825 MHz transmit and 866 to 870 MHz receive bands), with gain ranging between 6 and 12 dBic, that are suitable for land mobile vehicles are presented. The antennas may be used within CONUS and ALASKA to communicate to and from a geosynchronous satellite. Depending on the type of steering mechanism, the antennas are broken down into three categories; (1) electronically scanned arrays with phase shifters, (2) electronically switched arrays with switchable power dividers/combiners, and (3) mechanically steered arrays. The operating characteristics of two of these design concepts, one a conformal antenna with electronic beam steering and the other a nonconformal design with mechanical steering, were evaluated with regard to two and three satellite system. Cost estimates of various antenna concepts were made and plotted against their overall gain performance.

  13. RGB visible light communication using mobile-phone camera and multi-input multi-output.

    PubMed

    Liang, Kevin; Chow, Chi-Wai; Liu, Yang

    2016-05-01

    Red, green, blue (RGB) light-emitting-diodes (LEDs) are used to increase the visible light communication (VLC) transmission capacity via wavelength-division-multiplexing (WDM), and the color image sensor in mobile phone is used to separate different color signals via a color filter array. However, due to the wide optical bandwidths of the color filters, there is a high spectral overlap among different channels, and a high inter-channel interference (ICI) happens. Here, we propose and demonstrate an RGB VLC transmission using CMOS image sensor with multi-input multi-output (MIMO) technique to mitigate the ICI and retrieve the three independent color channels in the rolling shutter pattern. Data pattern extinction-ratio (ER) enhancement and thresholding are deployed. PMID:27137554

  14. Enhanced spectral efficiency using bandwidth switchable SAW filtering for mobile satellite communications systems

    NASA Technical Reports Server (NTRS)

    Peach, Robert; Malarky, Alastair

    1990-01-01

    Currently proposed mobile satellite communications systems require a high degree of flexibility in assignment of spectral capacity to different geographic locations. Conventionally this results in poor spectral efficiency which may be overcome by the use of bandwidth switchable filtering. Surface acoustic wave (SAW) technology makes it possible to provide banks of filters whose responses may be contiguously combined to form variable bandwidth filters with constant amplitude and phase responses across the entire band. The high selectivity possible with SAW filters, combined with the variable bandwidth capability, makes it possible to achieve spectral efficiencies over the allocated bandwidths of greater than 90 percent, while retaining full system flexibility. Bandwidth switchable SAW filtering (BSSF) achieves these gains with a negligible increase in hardware complexity.

  15. Low earth orbit mobile communication satellite systems: A two-year history since WARC-92

    NASA Astrophysics Data System (ADS)

    Dumont, Patrick

    1996-01-01

    Mobile communication satellite systems have regularly made the headlines of space industry publications in the 1990s. This paper adopts a new perspective—how the systems evolve over time—to describe the main technical features of the two main types: -big LEO systems with voice capabilities: Iridium, Globalstar, Odyssey, Inmarsat P21 -little LEO non-voice systems: Orbcomm, Starsys. This approach reveals the considerable changes, even upheavals, that have affected the design of system components. The apparent stability in the designs is due to outside observers gradually and perhaps unquestioningly perceiving the changes. People's capacity to forget, compounded by the attraction of innovation, may also have a lot to do with it. We present the likely causes of these changes: regulatory environment, market forces, financial arrangements, being at the early design stage, etc. We also analyze the effects of these forces on the systems, and deduce the general trends.

  16. The design and networking of dynamic satellite constellations for global mobile communication systems

    NASA Technical Reports Server (NTRS)

    Cullen, Cionaith J.; Benedicto, Xavier; Tafazolli, Rahim; Evans, Barry

    1993-01-01

    Various design factors for mobile satellite systems, whose aim is to provide worldwide voice and data communications to users with hand-held terminals, are examined. Two network segments are identified - the ground segment (GS) and the space segment (SS) - and are seen to be highly dependent on each other. The overall architecture must therefore be adapted to both of these segments, rather than each being optimized according to its own criteria. Terrestrial networks are grouped and called the terrestrial segment (TS). In the SS, of fundamental importance is the constellation altitude. The effect of the altitude on decisions such as constellation design choice and on network aspects like call handover statistics are fundamental. Orbit resonance is introduced and referred to throughout. It is specifically examined for its useful properties relating to GS/SS connectivities.

  17. Turbo product codes and their application in the fourth-generation mobile communication system

    NASA Astrophysics Data System (ADS)

    He, Yejun; Zhu, Guangxi; Liu, Ying Zhuang; Liu, Jian

    2004-04-01

    In this paper, we firstly present turbo product codes (TPCs) for forward error correction (FEC) coding, including TPCs encoding process and decoding principle, and then compare TPCs with turbo convolutional codes (TCCs) error coding solution. The performance of TPCs is shown to be closer to the Shannon limit than TCCs. Secondly, we introduce TPCs" application in the 4th generation (4G) mobile communication system which is being developed in our country at present. The concept of TPC-OFDM system which promises higher code rate than conventional OFDM is first modified. Finally, simulation results show that the simplified 4G uplink systems offer Bit Error Rate of nearly 0 over IMT-2000 channel at Eb/N0 > 15dB.

  18. Proceedings of the Eighteenth NASA Propagation Experimenters Meeting (NAPEX 18) and the Advanced Communications Technology Satellite (ACTS) Propagation Studies Miniworkshop

    NASA Technical Reports Server (NTRS)

    Davarian, Faramaz (Editor)

    1994-01-01

    The NASA Propagation Experimenters Meeting (NAPEX), supported by the NASA Propagation Program, is convened annually to discuss studies made on radio wave propagation by investigators from domestic and international organizations. Participants included representatives from Canada, the Netherlands, England, and the United States, including researchers from universities, government agencies, and private industry. The meeting was organized into two technical sessions. The first session was dedicated to slant path propagation studies and experiments. The second session focused on propagation studies for mobile, personal, and sound broadcast systems. In total, 14 technical papers and some informal contributions were presented. Preceding NAPEX_17, the Advanced Communications Technology Satellite (ACTS) Propagation Studies Miniworkshop was held to review ACTS propagation activities.

  19. Advancing Unmanned Aircraft Sensor Collection and Communication Capabilities with Optical Communications

    NASA Astrophysics Data System (ADS)

    Lukaczyk, T.

    2015-12-01

    Unmanned aircraft systems (UAS) are now being used for monitoring climate change over both land and seas. Their uses include monitoring of cloud conditions and atmospheric composition of chemicals and aerosols due to pollution, dust storms, fires, volcanic activity and air-sea fluxes. Additional studies of carbon flux are important for various ecosystem studies of both marine and terrestrial environments specifically, and can be related to climate change dynamics. Many measurements are becoming more complex as additional sensors become small enough to operate on more widely available small UAS. These include interferometric radars as well as scanning and fan-beam lidar systems which produce data streams even greater than those of high resolution video. These can be used to precisely map surfaces of the earth, ocean or ice features that are important for a variety of earth system studies. As these additional sensor capabilities are added to UAS the ability to transmit data back to ground or ship monitoring sites is limited by traditional wireless communication protocols. We describe results of tests of optical communication systems that provide significantly greater communication bandwidths for UAS, and discuss both the bandwidth and effective range of these systems, as well as their power and weight requirements both for systems on UAS, as well as those of ground-based receiver stations. We justify our additional use of Delay and Disruption Tolerant Networking (DTN) communication protocols with optical communication methods to ensure security and continuity of command and control operations. Finally, we discuss the implications for receiving, geo-referencing, archiving and displaying data streams from sensors communicated via optical communication to better enable real-time anomaly detection and adaptive sampling capabilities using multiple UAS or other unmanned or manned systems.

  20. Advances in high-speed low-latency communications for nanopositioning in advanced microscopy

    NASA Astrophysics Data System (ADS)

    Jordan, Scott C.

    2012-06-01

    We present a comparison of classical and recently developed communications interfacing technologies relevant to scanned imaging. We adopt an applications perspective, with a focus on interfacing techniques as enablers for enhanced resolution, speed, stability, information density or similar benefits. A wealth of such applications have emerged, ranging from nanoscale-stabilized force microscopy yielding 100X resolution improvement thanks to leveraging the latest in interfacing capabilities, to novel approaches in analog interfacing which improve data density and DAC resolution by several orders of magnitude. Our intent is to provide tools to understand, select and implement advanced interfacing to take applications to the next level. We have entered an era in which new interfacing techniques are enablers, in their own right, for novel imaging techniques. For example, clever leveraging of new interfacing technologies has yielded nanoscale stabilization and atomic-force microscopy (AFM) resolution enhancement. To assist in choosing and implementing interfacing strategies that maximize performance and enable new capabilities, we review available interfaces such as USB2, GPIB and Ethernet against the specific needs of positioning for the scanned-imaging community. We spotlight recent developments such as LabVIEW FPGA, which allows non-specialists to quickly devise custom logic and interfaces of unprecedentedly high performance and parallelism. Notable applications are reviewed, including a clever amalgamation of AFM and optical tweezers and a picometer-scaleaccuracy interferometer devised for ultrafine positioning validation. We note the Serial Peripheral Interface (SPI), emerging as a high-speed/low-latency instrumentation interface. The utility of instrument-specific parallel (PIO) and TTL sync/trigger (DIO) interfaces is also discussed. Requirements of tracking and autofocus are reviewed against the time-critical needs of typical applications (to avoid, for example

  1. Hysteresis in consumer markets with focus on the mobile communications market

    NASA Astrophysics Data System (ADS)

    Twomey, C.

    2008-11-01

    Our aim here is to try to identify hysteresis in the switching patterns of consumers in the Irish mobile phone industry. It was not until the introduction by the Communication Regulator of full-number portability that consumers began to take advantage of the savings that switching mobile phone operator could produce. As with most relatively new industries, the awareness of savings is clouded by a lack of understanding of whats on offer and an underlying fear of change from something they have only just started to comprehend. With people changing company loyalties more frequently than ever at the prospect of better, more cost-efficient services, it is now the million euro question for the phone companies on how close they should match each others' offers to maximize their profits, and what their best pricing strategy should be to obtain an even larger share of the market. Through the use of experimental economics and by modelling switching behaviour using the Preisach model, along with observed and market data, we hope to both pose this problem and start the journey to answering this question.

  2. Power attenuation characteristics as switch-over criterion in personal satellite mobile communications

    NASA Technical Reports Server (NTRS)

    Castro, Jonathan P.

    1993-01-01

    A third generation mobile system intends to support communications in all environments (i.e., outdoors, indoors at home or office and when moving). This system will integrate services that are now available in architectures such as cellular, cordless, mobile data networks, paging, including satellite services to rural areas. One way through which service integration will be made possible is by supporting a hierarchical cellular structure based on umbrella cells, macro cells, micro and pico cells. In this type of structure, satellites are part of the giant umbrella cells allowing continuous global coverage, the other cells belong to cities, neighborhoods, and buildings respectively. This does not necessarily imply that network operation of terrestrial and satellite segments interconnect to enable roaming and spectrum sharing. However, the cell concept does imply hand-off between different cell types, which may involve change of frequency. Within this propsective, the present work uses power attenuation characteristics to determine a dynamic criterion that allows smooth transition from space to terrestrial networks. The analysis includes a hybrid channel that combines Rician, Raleigh and Log Normal fading characteristics.

  3. Development of a mobile emergency patient information and imaging communication system based on CDMA-1X EVDO

    NASA Astrophysics Data System (ADS)

    Yang, Keon Ho; Jung, Haijo; Kang, Won-Suk; Jang, Bong Mun; Kim, Joong Il; Han, Dong Hoon; Yoo, Sun-Kook; Yoo, Hyung-Sik; Kim, Hee-Joung

    2006-03-01

    The wireless mobile service with a high bit rate using CDMA-1X EVDO is now widely used in Korea. Mobile devices are also increasingly being used as the conventional communication mechanism. We have developed a web-based mobile system that communicates patient information and images, using CDMA-1X EVDO for emergency diagnosis. It is composed of a Mobile web application system using the Microsoft Windows 2003 server and an internet information service. Also, a mobile web PACS used for a database managing patient information and images was developed by using Microsoft access 2003. A wireless mobile emergency patient information and imaging communication system is developed by using Microsoft Visual Studio.NET, and JPEG 2000 ActiveX control for PDA phone was developed by using the Microsoft Embedded Visual C++. Also, the CDMA-1X EVDO is used for connections between mobile web servers and the PDA phone. This system allows fast access to the patient information database, storing both medical images and patient information anytime and anywhere. Especially, images were compressed into a JPEG2000 format and transmitted from a mobile web PACS inside the hospital to the radiologist using a PDA phone located outside the hospital. Also, this system shows radiological images as well as physiological signal data, including blood pressure, vital signs and so on, in the web browser of the PDA phone so radiologists can diagnose more effectively. Also, we acquired good results using an RW-6100 PDA phone used in the university hospital system of the Sinchon Severance Hospital in Korea.

  4. Baseband processor development for the Advanced Communications Satellite Program

    NASA Technical Reports Server (NTRS)

    Moat, D.; Sabourin, D.; Stilwell, J.; Mccallister, R.; Borota, M.

    1982-01-01

    An onboard-baseband-processor concept for a satellite-switched time-division-multiple-access (SS-TDMA) communication system was developed for NASA Lewis Research Center. The baseband processor routes and controls traffic on an individual message basis while providing significant advantages in improved link margins and system flexibility. Key technology developments required to prove the flight readiness of the baseband-processor design are being verified in a baseband-processor proof-of-concept model. These technology developments include serial MSK modems, Clos-type baseband routing switch, a single-chip CMOS maximum-likelihood convolutional decoder, and custom LSL implementation of high-speed, low-power ECL building blocks.

  5. Mobile telemedicine: a survey study.

    PubMed

    Lin, Chin-Feng

    2012-04-01

    Telemedicine involves the use of advanced and reliable communication techniques to deliver biomedical signals over long distances. In such systems, biomedical information is transmitted using wireline or wireless communication systems. Mobile telemedicine is an improved form of telemedicine, in which advanced wireless communication systems are used to deliver the biomedical signals of patients at any place and any time. Mobile telemedicine employs advanced concepts and techniques from the fields of electrical engineering, computer science, biomedical engineering, and medicine to overcome the restrictions involved in conventional telemedicine and realize an improvement in the quality of service of medicine. In this paper, we study several mobile telemedicine systems, and it is important to gain a good understanding of mobile telemedicine systems because in the further, such systems are expected to become ubiquitous for the delivery of biomedical signals for medicine. PMID:20703699

  6. R and D limited partnerships (possible applications in advanced communications satellite technology experiment program)

    NASA Technical Reports Server (NTRS)

    1985-01-01

    Typical R&D limited partnership arrangements, advantages and disadvantages of R&D limited partnership (RDLPs) and antitrust and tax implications are described. A number of typical forms of RDLPs are described that may be applicable for use in stimulating R&D and experimental programs using the advanced communications technology satellite. The ultimate goal is to increase the rate of market penetration of goods and/or services based upon advanced satellite communications technology. The conditions necessary for these RDLP forms to be advantageous are outlined.

  7. Satellite applications to electric-utility communications needs. [land mobile satellite service

    NASA Technical Reports Server (NTRS)

    Horstein, M.; Barnett, R.

    1981-01-01

    Significant changes in the Nation's electric power systems are expected to result from the integration of new technology, possible during the next decade. Digital communications for monitor and control, exclusive of protective relaying, are expected to double or triple current traffic. A nationwide estimate of 13 Mb/s traffic is projected. Of this total, 8 Mb/s is attributed to the bulk-power system as it is now being operated (4 Mb/s). This traffic could be accommodated by current communications satellites using 3- to 4.5-m-diameter ground terminals costing $35,000 to $70,000 each. The remaining 5-Mb/s traffic is attributed to new technology concepts integrated into the distribution system. Such traffic is not compatible with current satellite technology because it requires small, low-cost ground terminals. Therefore, a high effective isotropic radiated power satellite, such as the one being planned by NASA for the Land Mobile Satellite Service, is required.

  8. Adaptive data rate SSMA system for personal and mobile satellite communications

    NASA Technical Reports Server (NTRS)

    Ikegami, Tetsushi; Takahashi, Takashi; Arakaki, Yoshiya; Wakana, Hiromitsu

    1995-01-01

    An adaptive data rate SSMA (spread spectrum multiple access) system is proposed for mobile and personal multimedia satellite communications without the aid of system control earth stations. This system has a constant occupied bandwidth and has variable data rates and processing gains to mitigate communication link impairments such as fading, rain attenuation and interference as well as to handle variable data rate on demand. Proof of concept hardware for 6MHz bandwidth transponder is developed, that uses offset-QPSK (quadrature phase shift keying) and MSK (minimum shift keying) for direct sequence spread spectrum modulation and handle data rates of 4k to 64kbps. The RS422 data interface, low rate voice and H.261 video codecs are installed. The receiver is designed with coherent matched filter technique to achieve fast code acquisition, AFC (automatic frequency control) and coherent detection with minimum hardware losses in a single matched filter circuit. This receiver structure facilitates variable data rate on demand during a call. This paper shows the outline of the proposed system and the performance of the prototype equipment.

  9. Reducing interferences in wireless communication systems by mobile agents with recurrent neural networks-based adaptive channel equalization

    NASA Astrophysics Data System (ADS)

    Beritelli, Francesco; Capizzi, Giacomo; Lo Sciuto, Grazia; Napoli, Christian; Tramontana, Emiliano; Woźniak, Marcin

    2015-09-01

    Solving channel equalization problem in communication systems is based on adaptive filtering algorithms. Today, Mobile Agents (MAs) with Recurrent Neural Networks (RNNs) can be also adopted for effective interference reduction in modern wireless communication systems (WCSs). In this paper MAs with RNNs are proposed as novel computing algorithms for reducing interferences in WCSs performing an adaptive channel equalization. The method to provide it is so called MAs-RNNs. We perform the implementation of this new paradigm for interferences reduction. Simulations results and evaluations demonstrates the effectiveness of this approach and as better transmission performance in wireless communication network can be achieved by using the MAs-RNNs based adaptive filtering algorithm.

  10. Brief Report: A Mobile Application to Treat Prosodic Deficits in Autism Spectrum Disorder and Other Communication Impairments: A Pilot Study

    ERIC Educational Resources Information Center

    Simmons, Elizabeth Schoen; Paul, Rhea; Shic, Frederick

    2016-01-01

    This study examined the acceptability of a mobile application, "SpeechPrompts," designed to treat prosodic disorders in children with ASD and other communication impairments. Ten speech-language pathologists (SLPs) in public schools and 40 of their students, 5-19 years with prosody deficits participated. Students received treatment with…

  11. Presentations of the Ninth Advanced Communications Technology Satellite Propagation Studies Workshop (APSW IX)

    NASA Technical Reports Server (NTRS)

    Golshan, Nasser (Editor)

    1997-01-01

    The Advanced Communications Technology Satellite Propagation Studies Workshop (APSW) is convened each year to present the results of the ACTS Propagation Campaign. Representatives from the satellite communications (satcom) industry, academia, and government are invited to APSW for discussions and exchange of information. The ACTS Propagation campaign is completing three years of Ka-Band data collection at seven sites in North America. Through this effort, NASA is making a major contribution to growth of satcom services by providing timely propagation data and models for predicting the performance of Ka-Band satellite communications systems.

  12. Advanced Communications Technology Satellite (ACTS): Design and on-orbit performance measurements

    NASA Technical Reports Server (NTRS)

    Gargione, F.; Acosta, R.; Coney, T.; Krawczyk, R.

    1995-01-01

    The Advanced Communications Technology Satellite (ACTS), developed and built by Lockheed Martin Astro space for the NASA Lewis Research Center, was launched in September 1993 on the shuttle STS 51 mission. ACTS is a digital experimental communications test bed that incorporates gigahertz bandwidth transponders operating at Ka band, hopping spot beams, on-board storage and switching, and dynamic rain fade compensation. This paper describes the ACTS enabling technologies, the design of the communications payload, the constraints imposed on the spacecraft bus, and the measurements conducted to verify the performance of the system in orbit.

  13. Advanced space communications architecture study. Volume 1: Executive summary

    NASA Technical Reports Server (NTRS)

    Horstein, Michael; Hadinger, Peter J.

    1987-01-01

    The technical feasibility and economic viability of satellite system architectures that are suitable for Customer Premise Service (CPS) communications is investigated. System evaluation is performed at 30/20 GHz (Ka-band); however, the system architectures examined are equally applicable to 14/11 GHz (Ku-band). Emphasis is placed on system that permit low cost user terminals. Frequency Division Multiple Access (FDMA) is used on the uplink, with typically 10,000 simultaneous accesses per satellite, each of 64 kbps. Bulk demodulators onboard the satellite, in combination with a baseband multiplexer, convert the many narrowband uplink signals into a small number of wideband data streams for downlink transmission. Single hop network interconnectivity is accomplished through use of downlink scanning beams. Each satellite is estimated to weigh 5600 lb and consume 6850W of power; the corresponding payload totals are 1000 lb and 5000W. Nonrecurring satellite cost is estimated at $110 million, with the first unit cost at $113 million. In large quantities, the user terminal cost estimate is $25,000.

  14. Advanced space communications architecture study. Volume 2: Technical report

    NASA Technical Reports Server (NTRS)

    Horstein, Michael; Hadinger, Peter J.

    1987-01-01

    The technical feasibility and economic viability of satellite system architectures that are suitable for customer premise service (CPS) communications are investigated. System evaluation is performed at 30/20 GHz (Ka-band); however, the system architectures examined are equally applicable to 14/11 GHz (Ku-band). Emphasis is placed on systems that permit low-cost user terminals. Frequency division multiple access (FDMA) is used on the uplink, with typically 10,000 simultaneous accesses per satellite, each of 64 kbps. Bulk demodulators onboard the satellite, in combination with a baseband multiplexer, convert the many narrowband uplink signals into a small number of wideband data streams for downlink transmission. Single-hop network interconnectivity is accomplished via downlink scanning beams. Each satellite is estimated to weigh 5600 lb and consume 6850W of power; the corresponding payload totals are 1000 lb and 5000 W. Nonrecurring satellite cost is estimated at $110 million, with the first-unit cost at $113 million. In large quantities, the user terminal cost estimate is $25,000. For an assumed traffic profile, the required system revenue has been computed as a function of the internal rate of return (IRR) on invested capital. The equivalent user charge per-minute of 64-kbps channel service has also been determined.

  15. Advanced Communication Technology Satellite (ACTS) multibeam antenna analysis and experiment

    NASA Technical Reports Server (NTRS)

    Acosta, Roberto J.; Lagin, Alan R.; Larko, Jeffrey M.; Narvaez, Adabelle

    1992-01-01

    One of the most important aspects of a satellite communication system design is the accurate estimation of antenna performance degradation. Pointing error, end coverage gain, peak gain degradation, etc. are the main concerns. The thermal or dynamic distortions of a reflector antenna structural system can affect the far-field antenna power distribution in a least four ways. (1) The antenna gain is reduced; (2) the main lobe of the antenna can be mispointed thus shifting the destination of the delivered power away from the desired locations; (3) the main lobe of the antenna pattern can be broadened, thus spreading the RF power over a larger area than desired; and (4) the antenna pattern sidelobes can increase, thus increasing the chances of interference among adjacent beams of multiple beam antenna system or with antenna beams of other satellites. The in-house developed NASA Lewis Research Center thermal/structural/RF analysis program was designed to accurately simulate the ACTS in-orbit thermal environment and predict the RF antenna performance. The program combines well establish computer programs (TRASYS, SINDA and NASTAN) with a dual reflector-physical optics RF analysis program. The ACTS multibeam antenna configuration is analyzed and several thermal cases are presented and compared with measurements (pre-flight).

  16. Satellite switched FDMA advanced communication technology satellite program

    NASA Technical Reports Server (NTRS)

    Atwood, S.; Higton, G. H.; Wood, K.; Kline, A.; Furiga, A.; Rausch, M.; Jan, Y.

    1982-01-01

    The satellite switched frequency division multiple access system provided a detailed system architecture that supports a point to point communication system for long haul voice, video and data traffic between small Earth terminals at Ka band frequencies at 30/20 GHz. A detailed system design is presented for the space segment, small terminal/trunking segment at network control segment for domestic traffic model A or B, each totaling 3.8 Gb/s of small terminal traffic and 6.2 Gb/s trunk traffic. The small terminal traffic (3.8 Gb/s) is emphasized, for the satellite router portion of the system design, which is a composite of thousands of Earth stations with digital traffic ranging from a single 32 Kb/s CVSD voice channel to thousands of channels containing voice, video and data with a data rate as high as 33 Mb/s. The system design concept presented, effectively optimizes a unique frequency and channelization plan for both traffic models A and B with minimum reorganization of the satellite payload transponder subsystem hardware design. The unique zoning concept allows multiple beam antennas while maximizing multiple carrier frequency reuse. Detailed hardware design estimates for an FDMA router (part of the satellite transponder subsystem) indicate a weight and dc power budget of 353 lbs, 195 watts for traffic model A and 498 lbs, 244 watts for traffic model B.

  17. The role of interpersonal communication in the process of knowledge mobilization within a community-based organization: a network analysis

    PubMed Central

    2014-01-01

    Background Diffusion of innovations theory has been widely used to explain knowledge mobilization of research findings. This theory posits that individuals who are more interpersonally connected within an organization may be more likely to adopt an innovation (e.g., research evidence) than individuals who are less interconnected. Research examining this tenet of diffusion of innovations theory in the knowledge mobilization literature is limited. The purpose of the present study was to use network analysis to examine the role of interpersonal communication in the adoption and mobilization of the physical activity guidelines for people with spinal cord injury (SCI) among staff in a community-based organization (CBO). Methods The study used a cross-sectional, whole-network design. In total, 56 staff completed the network survey. Adoption of the guidelines was assessed using Rogers’ innovation-decision process and interpersonal communication was assessed using an online network instrument. Results The patterns of densities observed within the network were indicative of a core-periphery structure revealing that interpersonal communication was greater within the core than between the core and periphery and within the periphery. Membership in the core, as opposed to membership in the periphery, was associated with greater knowledge of the evidence-based physical activity resources available and engagement in physical activity promotion behaviours (ps < 0.05). Greater in-degree centrality was associated with adoption of evidence-based behaviours (p < 0.05). Conclusions Findings suggest that interpersonal communication is associated with knowledge mobilization and highlight how the network structure could be improved for further dissemination efforts. Keywords: diffusion of innovations; network analysis; community-based organization; knowledge mobilization; knowledge translation, interpersonal communication. PMID:24886429

  18. Advanced Communication and Control Solutions of Distributed Energy Resources (DER)

    SciTech Connect

    Asgeirsson, Haukur; Seguin, Richard; Sherding, Cameron; de Bruet, Andre, G.; Broadwater, Robert; Dilek, Murat

    2007-01-10

    This report covers work performed in Phase II of a two phase project whose objective was to demonstrate the aggregation of multiple Distributed Energy Resources (DERs) and to offer them into the energy market. The Phase I work (DE-FC36-03CH11161) created an integrated, but distributed, system and procedures to monitor and control multiple DERs from numerous manufacturers connected to the electric distribution system. Procedures were created which protect the distribution network and personnel that may be working on the network. Using the web as the communication medium for control and monitoring of the DERs, the integration of information and security was accomplished through the use of industry standard protocols such as secure SSL,VPN and ICCP. The primary objective of Phase II was to develop the procedures for marketing the power of the Phase I aggregated DERs in the energy market, increase the number of DER units, and implement the marketing procedures (interface with ISOs) for the DER generated power. The team partnered with the Midwest Independent System Operator (MISO), the local ISO, to address the energy market and demonstrate the economic dispatch of DERs in response to market signals. The selection of standards-based communication technologies offers the ability of the system to be deployed and integrated with other utilities’ resources. With the use of a data historian technology to facilitate the aggregation, the developed algorithms and procedures can be verified, audited, and modified. The team has demonstrated monitoring and control of multiple DERs as outlined in phase I report including procedures to perform these operations in a secure and safe manner. In Phase II, additional DER units were added. We also expanded on our phase I work to enhance communication security and to develop the market model of having DERs, both customer and utility owned, participate in the energy market. We are proposing a two-part DER energy market model--a utility

  19. Advances in ion mobility spectrometry–mass spectrometry reveal key insights into amyloid assembly☆

    PubMed Central

    Woods, L.A.; Radford, S.E.; Ashcroft, A.E.

    2013-01-01

    Interfacing ion mobility spectrometry to mass spectrometry (IMS–MS) has enabled mass spectrometric analyses to extend into an extra dimension, providing unrivalled separation and structural characterization of lowly populated species in heterogeneous mixtures. One biological system that has benefitted significantly from such advances is that of amyloid formation. Using IMS–MS, progress has been made into identifying transiently populated monomeric and oligomeric species for a number of different amyloid systems and has led to an enhanced understanding of the mechanism by which small molecules modulate amyloid formation. This review highlights recent advances in this field, which have been accelerated by the commercial availability of IMS–MS instruments. This article is part of a Special Issue entitled: Mass spectrometry in structural biology. PMID:23063533

  20. Health Care Professionals' Death Attitudes, Experiences, and Advance Directive Communication Behavior

    ERIC Educational Resources Information Center

    Black, Kathy

    2007-01-01

    The study surveyed 135 health care professionals (74 nurses, 32 physicians, and 29 social workers) to examine their personal death attitudes and experiences in relation to their reported advance directive communication practice behavior. Negative correlations were found between collaborating with other health care professionals regarding the…

  1. Prospects for Significant Theoretical Advances in Communication: The Role of the Interesting Question.

    ERIC Educational Resources Information Center

    Gouran, Dennis S.

    This paper discusses ways in which the field of speech communication can be advanced. The first half of the paper characterizes the objectivist and subjectivist views of how knowledge is acquired and the forms of inquiry to which these views have led. The remainder of the paper demonstrates the role that the "interesting question" (one for which…

  2. Application of advanced on-board processing concepts to future satellite communications systems

    NASA Technical Reports Server (NTRS)

    Katz, J. L.; Hoffman, M.; Kota, S. L.; Ruddy, J. M.; White, B. F.

    1979-01-01

    An initial definition of on-board processing requirements for an advanced satellite communications system to service domestic markets in the 1990's is presented. An exemplar system architecture with both RF on-board switching and demodulation/remodulation baseband processing was used to identify important issues related to system implementation, cost, and technology development.

  3. OSI-compatible protocols for mobile-satellite communications: The AMSS experience

    NASA Technical Reports Server (NTRS)

    Moher, Michael

    1990-01-01

    The protocol structure of the international aeronautical mobile satellite service (AMSS) is reviewed with emphasis on those aspects of protocol performance, validation, and conformance which are peculiar to mobile services. This is in part an analysis of what can be learned from the AMSS experience with protocols which is relevant to the design of other mobile satellite data networks, e.g., land mobile.

  4. Technology-design-manufacturing co-optimization for advanced mobile SoCs

    NASA Astrophysics Data System (ADS)

    Yang, Da; Gan, Chock; Chidambaram, P. R.; Nallapadi, Giri; Zhu, John; Song, S. C.; Xu, Jeff; Yeap, Geoffrey

    2014-03-01

    How to maintain the Moore's Law scaling beyond the 193 immersion resolution limit is the key question semiconductor industry needs to answer in the near future. Process complexity will undoubtfully increase for 14nm node and beyond, which brings both challenges and opportunities for technology development. A vertically integrated design-technologymanufacturing co-optimization flow is desired to better address the complicated issues new process changes bring. In recent years smart mobile wireless devices have been the fastest growing consumer electronics market. Advanced mobile devices such as smartphones are complex systems with the overriding objective of providing the best userexperience value by harnessing all the technology innovations. Most critical system drivers are better system performance/power efficiency, cost effectiveness, and smaller form factors, which, in turns, drive the need of system design and solution with More-than-Moore innovations. Mobile system-on-chips (SoCs) has become the leading driver for semiconductor technology definition and manufacturing. Here we highlight how the co-optimization strategy influenced architecture, device/circuit, process technology and package, in the face of growing process cost/complexity and variability as well as design rule restrictions.

  5. Accuracy Evaluation of a Mobile Mapping System with Advanced Statistical Methods

    NASA Astrophysics Data System (ADS)

    Toschi, I.; Rodríguez-Gonzálvez, P.; Remondino, F.; Minto, S.; Orlandini, S.; Fuller, A.

    2015-02-01

    This paper discusses a methodology to evaluate the precision and the accuracy of a commercial Mobile Mapping System (MMS) with advanced statistical methods. So far, the metric potentialities of this emerging mapping technology have been studied in few papers, where generally the assumption that errors follow a normal distribution is made. In fact, this hypothesis should be carefully verified in advance, in order to test how well the Gaussian classic statistics can adapt to datasets that are usually affected by asymmetrical gross errors. The workflow adopted in this study relies on a Gaussian assessment, followed by an outlier filtering process. Finally, non-parametric statistical models are applied, in order to achieve a robust estimation of the error dispersion. Among the different MMSs available on the market, the latest solution provided by RIEGL is here tested, i.e. the VMX-450 Mobile Laser Scanning System. The test-area is the historic city centre of Trento (Italy), selected in order to assess the system performance in dealing with a challenging and historic urban scenario. Reference measures are derived from photogrammetric and Terrestrial Laser Scanning (TLS) surveys. All datasets show a large lack of symmetry that leads to the conclusion that the standard normal parameters are not adequate to assess this type of data. The use of non-normal statistics gives thus a more appropriate description of the data and yields results that meet the quoted a-priori errors.

  6. Low-mobility channel tracking for MIMO-OFDM communication systems

    NASA Astrophysics Data System (ADS)

    Pagadarai, Srikanth; Wyglinski, Alexander M.; Anderson, Christopher R.

    2013-12-01

    It is now well understood that by exploiting the available additional spatial dimensions, multiple-input multiple-output (MIMO) communication systems provide capacity gains, compared to a single-input single-output systems without increasing the overall transmit power or requiring additional bandwidth. However, these large capacity gains are feasible only when the perfect knowledge of the channel is available to the receiver. Consequently, when the channel knowledge is imperfect, as is common in practical settings, the impact of the achievable capacity needs to be evaluated. In this study, we begin with a general MIMO framework at the outset and specialize it to the case of orthogonal frequency division multiplexing (OFDM) systems by decoupling channel estimation from data detection. Cyclic-prefixed OFDM systems have attracted widespread interest due to several appealing characteristics not least of which is the fact that a single-tap frequency-domain equalizer per subcarrier is sufficient due to the circulant structure of the resulting channel matrix. We consider a low-mobility wireless channel which exhibits inter-block channel variations and apply Kalman tracking when MIMO-OFDM communication is performed. Furthermore, we consider the signal transmission to contain a stream of training and information symbols followed by information symbols alone. By relying on predicted channel states when training symbols are absent, we aim to understand how the improvements in channel capacity are affected by imperfect channel knowledge. We show that the Kalman recursion procedure can be simplified by the optimal minimum mean square error training design. Using the simplified recursion, we derive capacity upper and lower bounds to evaluate the performance of the system.

  7. Modified Advanced Crew Escape Suit Intravehicular Activity Suit for Extravehicular Activity Mobility Evaluations

    NASA Technical Reports Server (NTRS)

    Watson, Richard D.

    2014-01-01

    The use of an intravehicular activity (IVA) suit for a spacewalk or extravehicular activity (EVA) was evaluated for mobility and usability in the Neutral Buoyancy Laboratory (NBL) environment at the Sonny Carter Training Facility near NASA Johnson Space Center in Houston, Texas. The Space Shuttle Advanced Crew Escape Suit was modified to integrate with the Orion spacecraft. The first several missions of the Orion Multi-Purpose Crew Vehicle will not have mass available to carry an EVA-specific suit; therefore, any EVA required will have to be performed by the Modified Advanced Crew Escape Suit (MACES). Since the MACES was not designed with EVA in mind, it was unknown what mobility the suit would be able to provide for an EVA or whether a person could perform useful tasks for an extended time inside the pressurized suit. The suit was evaluated in multiple NBL runs by a variety of subjects, including crewmembers with significant EVA experience. Various functional mobility tasks performed included: translation, body positioning, tool carrying, body stabilization, equipment handling, and tool usage. Hardware configurations included with and without Thermal Micrometeoroid Garment, suit with IVA gloves and suit with EVA gloves. Most tasks were completed on International Space Station mock-ups with existing EVA tools. Some limited tasks were completed with prototype tools on a simulated rocky surface. Major findings include: demonstrating the ability to weigh-out the suit, understanding the need to have subjects perform multiple runs prior to getting feedback, determining critical sizing factors, and need for adjusting suit work envelope. Early testing demonstrated the feasibility of EVA's limited duration and limited scope. Further testing is required with more flight-like tasking and constraints to validate these early results. If the suit is used for EVA, it will require mission-specific modifications for umbilical management or Primary Life Support System integration

  8. The mobilize center: an NIH big data to knowledge center to advance human movement research and improve mobility.

    PubMed

    Ku, Joy P; Hicks, Jennifer L; Hastie, Trevor; Leskovec, Jure; Ré, Christopher; Delp, Scott L

    2015-11-01

    Regular physical activity helps prevent heart disease, stroke, diabetes, and other chronic diseases, yet a broad range of conditions impair mobility at great personal and societal cost. Vast amounts of data characterizing human movement are available from research labs, clinics, and millions of smartphones and wearable sensors, but integration and analysis of this large quantity of mobility data are extremely challenging. The authors have established the Mobilize Center (http://mobilize.stanford.edu) to harness these data to improve human mobility and help lay the foundation for using data science methods in biomedicine. The Center is organized around 4 data science research cores: biomechanical modeling, statistical learning, behavioral and social modeling, and integrative modeling. Important biomedical applications, such as osteoarthritis and weight management, will focus the development of new data science methods. By developing these new approaches, sharing data and validated software tools, and training thousands of researchers, the Mobilize Center will transform human movement research. PMID:26272077

  9. Weather Information Communication Technologies for Increased Safety and Mobility in the National Airspace System

    NASA Technical Reports Server (NTRS)

    Hilderman, Don R.

    2006-01-01

    The purpose of the NASA Glenn Research Center Weather Information Communications (WINCOMM) project was to develop advanced communications and information technologies to enable the high-quality and timely dissemination of strategic weather information between the flight deck and ground users as well as tactical turbulence hazard information between relevant aircraft and to the ground. This report will document and reference accomplishments on the dissemination of weather information during the en route phase of flight from ground-based weather information providers to the flight deck (ground-to-air), from airborne meteorological sensors to ground users (air-to-ground), and weather turbulence and icing hazard information between relevant aircraft (air-to-air). In addition, references in this report will demonstrate the architecture necessary to implement and perform successful transmission and reception of weather information to the cockpit, show that weather information flow does not impact "normal" traffic, demonstrate the feasibility of operational implementation, and lay foundation for future data link development.

  10. Dual-Stack Single-Radio Communication Architecture for UAV Acting As a Mobile Node to Collect Data in WSNs.

    PubMed

    Sayyed, Ali; de Araújo, Gustavo Medeiros; Bodanese, João Paulo; Becker, Leandro Buss

    2015-01-01

    The use of mobile nodes to collect data in a Wireless Sensor Network (WSN) has gained special attention over the last years. Some researchers explore the use of Unmanned Aerial Vehicles (UAVs) as mobile node for such data-collection purposes. Analyzing these works, it is apparent that mobile nodes used in such scenarios are typically equipped with at least two different radio interfaces. The present work presents a Dual-Stack Single-Radio Communication Architecture (DSSRCA), which allows a UAV to communicate in a bidirectional manner with a WSN and a Sink node. The proposed architecture was specifically designed to support different network QoS requirements, such as best-effort and more reliable communications, attending both UAV-to-WSN and UAV-to-Sink communications needs. DSSRCA was implemented and tested on a real UAV, as detailed in this paper. This paper also includes a simulation analysis that addresses bandwidth consumption in an environmental monitoring application scenario. It includes an analysis of the data gathering rate that can be achieved considering different UAV flight speeds. Obtained results show the viability of using a single radio transmitter for collecting data from the WSN and forwarding such data to the Sink node. PMID:26389911

  11. Dual-Stack Single-Radio Communication Architecture for UAV Acting As a Mobile Node to Collect Data in WSNs

    PubMed Central

    Sayyed, Ali; Medeiros de Araújo, Gustavo; Bodanese, João Paulo; Buss Becker, Leandro

    2015-01-01

    The use of mobile nodes to collect data in a Wireless Sensor Network (WSN) has gained special attention over the last years. Some researchers explore the use of Unmanned Aerial Vehicles (UAVs) as mobile node for such data-collection purposes. Analyzing these works, it is apparent that mobile nodes used in such scenarios are typically equipped with at least two different radio interfaces. The present work presents a Dual-Stack Single-Radio Communication Architecture (DSSRCA), which allows a UAV to communicate in a bidirectional manner with a WSN and a Sink node. The proposed architecture was specifically designed to support different network QoS requirements, such as best-effort and more reliable communications, attending both UAV-to-WSN and UAV-to-Sink communications needs. DSSRCA was implemented and tested on a real UAV, as detailed in this paper. This paper also includes a simulation analysis that addresses bandwidth consumption in an environmental monitoring application scenario. It includes an analysis of the data gathering rate that can be achieved considering different UAV flight speeds. Obtained results show the viability of using a single radio transmitter for collecting data from the WSN and forwarding such data to the Sink node. PMID:26389911

  12. Mobile Learning Using Mobile Phones

    ERIC Educational Resources Information Center

    Vicente, Paula

    2013-01-01

    The participation in mobile learning programs is conditioned by having/using mobile communication technology. Those who do not have or use such technology cannot participate in mobile learning programs. This study evaluates who are the most likely participants of mobile learning programs by examining the demographic profile and mobile phone usage…

  13. Land Mobile Satellite Service (LMSS) channel simulator: An end-to-end hardware simulation and study of the LMSS communications links

    NASA Technical Reports Server (NTRS)

    Salmasi, A. B. (Editor); Springett, J. C.; Sumida, J. T.; Richter, P. H.

    1984-01-01

    The design and implementation of the Land Mobile Satellite Service (LMSS) channel simulator as a facility for an end to end hardware simulation of the LMSS communications links, primarily with the mobile terminal is described. A number of studies are reported which show the applications of the channel simulator as a facility for validation and assessment of the LMSS design requirements and capabilities by performing quantitative measurements and qualitative audio evaluations for various link design parameters and channel impairments under simulated LMSS operating conditions. As a first application, the LMSS channel simulator was used in the evaluation of a system based on the voice processing and modulation (e.g., NBFM with 30 kHz of channel spacing and a 2 kHz rms frequency deviation for average talkers) selected for the Bell System's Advanced Mobile Phone Service (AMPS). The various details of the hardware design, qualitative audio evaluation techniques, signal to channel impairment measurement techniques, the justifications for criteria of different parameter selection in regards to the voice processing and modulation methods, and the results of a number of parametric studies are further described.

  14. A comparison of metropolitan and non-metropolitan employment characteristics: Indications of the size of non-metropolitan mobile communication services user classes

    NASA Technical Reports Server (NTRS)

    Wilcox, R. E.

    1985-01-01

    The similarities and differences between areas inside and outside U.S. metropolitan areas were evaluated in terms of their commercial/industrial and government employment characteristics. The comparison focuses on the levels, shares, and composition of employment in the commercial/industrial and government sectors that represent potential classes of land mobile communications users. The major findings of the analysis are as follows: (1) non-metropolitan commercial/industrial user classes of land mobile communication services exist in significant numbers; (2) the compositions of non-metropolitan and metropolitan commercial/industrial user classes of land mobile communication services closely resemble each other; (3) non-metropolitan areas have significant levels of the government user classes that represent potential markets for land mobile communication services; and (4) non-metropolitan local governments have a significantly larger proportion of their employment in the primary user classes of private land mobile radio service than do metropolitan local governments.

  15. Flexible coprocessor architectures for ambient intelligent applications in the mobile communication and automotive domain

    NASA Astrophysics Data System (ADS)

    Gehrke, Winfried; Jachalsky, Joern; Wahle, Martin; Kruijtzer, Wido; Alba, Carlos; Sethuraman, Ramanathan

    2003-04-01

    Ambient Intelligent is expected to become one of the driving key factors of the semiconductors industry in this decade. One of the most promising areas in this respect is the advent of embedded smart imaging applications in a variety of consumer applications, like mobile communication devices and the automotive domain. The efficient VLSI implementation of these applications requires architectural concepts that enable the extraction of objects and associated information out of video sequences in real-time. The main architectural challenge is to find an appropriate trade-off between architectural flexibility and scalability in order to cope with moderate variations of the applied smart imaging algorithms on one hand and cost efficiency of the implementation on the other hand. This paper describes the algorithmic and architectural requirements for the implementation of smart imaging applications in the mentioned fields. The target system, based on an embedded RISC processor, embedded memory, and cores for accelerating essential functions, like morphological operations, connected component labeling, motion extraction etc., is presented. The functional system partitioning applied is based on HW acceleration of core functions that enable the extraction of low-level information out of the images of a video sequence. This information is provided to the embedded RISC processor for further abstraction of the image content information and interpretation of the image content by SW means. One of the focal points of this paper is the derivation of efficient architectural concepts for smart imaging coprocessors, acting as a system toolbox for accelerating the required smart imaging core functions.

  16. Requirements for a mobile communications satellite system. Part 3: Large space structures measurements study

    NASA Astrophysics Data System (ADS)

    Akle, W.

    1983-03-01

    This study report defines a set of tests and measurements required to characterize the performance of a Large Space System (LSS), and to scale this data to other LSS satellites. Requirements from the Mobile Communication Satellite (MSAT) configurations derived in the parent study were used. MSAT utilizes a large, mesh deployable antenna, and encompasses a significant range of LSS technology issues in the areas of structural/dynamics, control, and performance predictability. In this study, performance requirements were developed for the antenna. Special emphasis was placed on antenna surface accuracy, and pointing stability. Instrumentation and measurement systems, applicable to LSS, were selected from existing or on-going technology developments. Laser ranging and angulation systems, presently in breadboard status, form the backbone of the measurements. Following this, a set of ground, STS, and GEO-operational were investigated. A third scale (15 meter) antenna system as selected for ground characterization followed by STS flight technology development. This selection ensures analytical scaling from ground-to-orbit, and size scaling. Other benefits are cost and ability to perform reasonable ground tests. Detail costing of the various tests and measurement systems were derived and are included in the report.

  17. Requirements for a mobile communications satellite system. Volume 3: Large space structures measurements study

    NASA Technical Reports Server (NTRS)

    Akle, W.

    1983-01-01

    This study report defines a set of tests and measurements required to characterize the performance of a Large Space System (LSS), and to scale this data to other LSS satellites. Requirements from the Mobile Communication Satellite (MSAT) configurations derived in the parent study were used. MSAT utilizes a large, mesh deployable antenna, and encompasses a significant range of LSS technology issues in the areas of structural/dynamics, control, and performance predictability. In this study, performance requirements were developed for the antenna. Special emphasis was placed on antenna surface accuracy, and pointing stability. Instrumentation and measurement systems, applicable to LSS, were selected from existing or on-going technology developments. Laser ranging and angulation systems, presently in breadboard status, form the backbone of the measurements. Following this, a set of ground, STS, and GEO-operational were investigated. A third scale (15 meter) antenna system as selected for ground characterization followed by STS flight technology development. This selection ensures analytical scaling from ground-to-orbit, and size scaling. Other benefits are cost and ability to perform reasonable ground tests. Detail costing of the various tests and measurement systems were derived and are included in the report.

  18. Performance of the unique-word-reverse-modulation type demodulator for mobile satellite communications

    NASA Technical Reports Server (NTRS)

    Dohi, Tomohiro; Nitta, Kazumasa; Ueda, Takashi

    1993-01-01

    This paper proposes a new type of coherent demodulator, the unique-word (UW)-reverse-modulation type demodulator, for burst signal controlled by voice operated transmitter (VOX) in mobile satellite communication channels. The demodulator has three individual circuits: a pre-detection signal combiner, a pre-detection UW detector, and a UW-reverse-modulation type demodulator. The pre-detection signal combiner combines signal sequences received by two antennas and improves bit energy-to-noise power density ratio (E(sub b)/N(sub 0)) 2.5 dB to yield 10(exp -3) average bit error rate (BER) when carrier power-to-multipath power ratio (CMR) is 15 dB. The pre-detection UW detector improves UW detection probability when the frequency offset is large. The UW-reverse-modulation type demodulator realizes a maximum pull-in frequency of 3.9 kHz, the pull-in time is 2.4 seconds and frequency error is less than 20 Hz. The performances of this demodulator are confirmed through computer simulations and its effect is clarified in real-time experiments at a bit rate of 16.8 kbps using a digital signal processor (DSP).

  19. DSD (Double Soft Decision) concatenated FEC scheme on mobile satellite communication systems

    NASA Astrophysics Data System (ADS)

    Honda, Shunji; Kubota, Shuji; Kato, Shuzo

    1992-10-01

    In order to realize a higher-code-gain forward error correction scheme in mobile satellite communication systems, a novel concatenated coding scheme employng soft decision decoding for not only inner codes but also outer codes (DSD (Double Soft Decision) concatenated forward error correction scheme) is proposed. Soft-decision outer decoding can improve the bit error probability of inner decoded data, which traditionally cannot be sufficiently corrected in fading channels. In this scheme, likelihood information from an inner Viterbi decoder is used in the decoding of outer codes. A technique using the path memory circuit status 1.0 ratio for likelihood information is newly proposed, and it is shown that this method is the most reliable even though it requires the simplest hardware among the alternative likelihood information extracting methods. A computer simulation clarifies that the proposed DSD scheme improves Pe performance to one-third that of the conventional hard-decision outer decoding. Moreover, to reduce the interleaving delay time in fading channel or inner decoded data of concatenated codes, a parallel forward error correction scheme is proposed.

  20. DSD (Double Soft Decision) concatenated FEC Scheme in mobile satellite communication systems

    NASA Astrophysics Data System (ADS)

    Honda, Shunji; Kubota, Shuji; Kato, Shuzo

    This paper proposes a DSD (Double Soft Decision) concatenated forward error correction (FEC) scheme which employs soft decision decoding for not only inner codes but also outer codes to offer higher coding gain for mobile satellite communication systems. Soft decision outer decoding can improve the bit error probability Pe of inner decoded data which traditionally cannot be sufficiently corrected in fading channels. In this scheme, likelihood information form an inner Viterbi decoder is used is used as soft decision data to decode outer codes. A technique using the path memory circuit status 1,0 ratio for likelihood information is proposed, and it is shown that this method is the most reliable likelihood information extracting method even though its hardware is the simplest. A computer simulation shows that the proposed DSD scheme improves Pe performance to one-third that of a conventional hard decision outer decoding scheme. Moreover, to reduce the interleaving delay time of inner decoded data of concatenated codes, especially in fading channels, a parallel forward error correction scheme is proposed.

  1. Mobile healthcare informatics.

    PubMed

    Siau, Keng; Shen, Zixing

    2006-06-01

    Advances in wireless technology give pace to the rapid development of mobile applications. The coming mobile revolution will bring dramatic and fundamental changes to our daily life. It will influence the way we live, the way we do things, and the way we take care of our health. For the healthcare industry, mobile applications provide a new frontier in offering better care and services to patients, and a more flexible and mobile way of communicating with suppliers and patients. Mobile applications will provide important real time data for patients, physicians, insurers, and suppliers. In addition, it will revolutionalize the way information is managed in the healthcare industry and redefine the doctor - patient communication. This paper discusses different aspects of mobile healthcare. Specifically, it presents mobile applications in healthcare, and discusses possible challenges facing the development of mobile applications. Obstacles in developing mobile healthcare applications include mobile device limitations, wireless networking problems, infrastructure constraints, security concerns, and user distrust. Research issues in resolving or alleviating these problems are also discussed in the paper. PMID:16777784

  2. Advancing the art of satellite communications - Foreign competition spurs NASA Satcom research

    NASA Astrophysics Data System (ADS)

    Bulloch, C.

    1985-01-01

    Major advances in satellite communications technology in the US and Japan are detailed. Japan's Ka-band services aboard CS-2a and CS-2b, launched in 1973, are discussed, as well as plans for the ECS-2 and ACTS-E (Advanced Communications Technology Satellite) experimental projects. The ACTS-E would carry both a broadcasting payload operating at 27/22 GHz and a communication payload using the 50/40 GHz band. Japan's fourth generation CS-4, for start-up in the first half of the 1990's, is described as a 2-ton craft carrying 60-70 transponders, and providing capacity for up to 100,000 equivalent two-way voice channels via 10 or 20 scanning spotbeams. NASA's new programs are described as well, including the ACTS program, with a communications payload embodying signal-processing, message-routing, and traffic-management techniques, and the MSAT program, concentrating on narrow-band transmissions. Included are the technical description, operational parameters, and schematic layout of NASA's ACTS, and block diagrams of baseband processor for low burst rate communications switching on the ACTS.

  3. Communications spacecraft

    NASA Astrophysics Data System (ADS)

    Fordyce, Samuel W.

    Progress in the designs and performance capabilities of communications satellites is traced from the Echo 1 Al-coated mylar balloon in 1960 to systems planned for the 1990s and beyond. The services allowed with the passive balloon concept were too limited and led to Telstar spacecraft, with 600 voice channels, being placed in elliptical orbits. Geosynchronous communications began in 1963 with the Syncom satellite, which also carried television signals. The evolution of subsequent Intelsat and ANIK satellites is described, as are features of the Marisat, Marecs, and the DBS systems. The near-term capabilities for DBS, advanced communications satellites using TDMA techniques, and mobile communications systems are summarized, along with the NASA ACTS and MSAT-X satellites for exploring the necessary technologies. The roles the Space Station and unmanned GEO platforms will play in future satellite communications are discussed.

  4. Application of the advanced communications technology satellite for teleradiology and telemedicine

    NASA Astrophysics Data System (ADS)

    Stewart, Brent K.; Carter, Stephen J.; Rowberg, Alan H.

    1995-05-01

    The authors have an in-kind grant from NASA to investigate the application of the Advanced Communications Technology Satellite (ACTS) to teleradiology and telemedicine using the JPL developed ACTS Mobile Terminal (AMT) uplink. This experiment involves the transmission of medical imagery (CT, MR, CR, US and digitized radiographs including mammograms), between the ACTS/AMT and the University of Washington. This is accomplished by locating the AMT experiment van in various locations throughout Washington state, Idaho, Montana, Oregon and Hawaii. The medical images are transmitted from the ACTS to the downlink at the NASA Lewis Research Center (LeRC) in Cleveland, Ohio, consisting of AMT equipment and the high burst rate-link evaluation terminal (HBR-LET). These images are then routed from LeRC to the University of Washington School of Medicine (UWSoM) through the Internet and public switched Integrated Serviced Digital Network (ISDN). Once images arrive in the UW Radiology Department, they are reviewed using both video monitor softcopy and laser-printed hardcopy. Compressed video teleconferencing and transmission of real-time ultrasound video between the AMT van and the UWSoM are also tested. Image quality comparisons are made using both subjective diagnostic criteria and quantitative engineering analysis. Evaluation is performed during various weather conditions (including rain to assess rain fade compensation algorithms). Compression techniques also are tested to evaluate their effects on image quality, allowing further evaluation of portable teleradiology/telemedicine at lower data rates and providing useful information for additional applications (e.g., smaller remote units, shipboard, emergency disaster, etc.). The medical images received at the UWSoM over the ACTS are directly evaluated against the original digital images. The project demonstrates that a portable satellite-land connection can provide subspecialty consultation and education for rural and remote

  5. Distress detection, location, and communications using advanced space technology. [satellite-borne synthetic aperture radar

    NASA Technical Reports Server (NTRS)

    Sivertson, W. E., Jr.

    1977-01-01

    This paper briefly introduces a concept for low-cost, global, day-night, all-weather disaster warning and assistance. Evolving, advanced space technology with passive radio frequency reflectors in conjunction with an imaging synthetic aperture radar is employed to detect, identify, locate, and provide passive communication with earth users in distress. This concept evolved from a broad NASA research on new global search and rescue techniques. Appropriate airborne radar test results from this research are reviewed and related to potential disaster applications. The analysis indicates the approach has promise for disaster communications relative to floods, droughts, earthquakes, volcanic eruptions, and severe storms.

  6. Compact, low profile antennas for MSAT and mini-M and Std-M land mobile satellite communications

    NASA Technical Reports Server (NTRS)

    Strickland, P. C.

    1995-01-01

    CAL Corporation has developed a new class of low profile radiating elements for use in planar phased array antennas. These new elements have been used in the design of a low cost, compact, low profile antenna unit for MSAT and INMARSAT Mini-M land mobile satellite communications. The antenna unit which measures roughly 32 cm in diameter by 5 cm deep incorporates a compact LNA and diplexer unit as well as a complete, low cost, beam steering system. CAL has also developed a low profile antenna unit for INMARSAT-M land mobile satellite communications. A number of these units, which utilize a microstrip patch array design, were put into service in 1994.

  7. Trade-off between land vehicle antenna cost and gain for satellite mobile communications

    NASA Technical Reports Server (NTRS)

    1984-01-01

    Trade-offs between antenna cost and gain made for nine antennas as a feasibility study for the experimental land mobile satellite system, M-SAT(X) reported. This system is under development by JPL-NASA for a mobile telephone system to be used throughout the continental USA and Alaska. The mobile antenna is a key element in the development of this system.

  8. Application of Vision Metrology to In-Orbit Measurement of Large Reflector Onboard Communication Satellite for Next Generation Mobile Satellite Communication

    NASA Astrophysics Data System (ADS)

    Akioka, M.; Orikasa, T.; Satoh, M.; Miura, A.; Tsuji, H.; Toyoshima, M.; Fujino, Y.

    2016-06-01

    Satellite for next generation mobile satellite communication service with small personal terminal requires onboard antenna with very large aperture reflector larger than twenty meters diameter because small personal terminal with lower power consumption in ground base requires the large onboard reflector with high antenna gain. But, large deployable antenna will deform in orbit because the antenna is not a solid dish but the flexible structure with fine cable and mesh supported by truss. Deformation of reflector shape deteriorate the antenna performance and quality and stability of communication service. However, in case of digital beam forming antenna with phased array can modify the antenna beam performance due to adjustment of excitation amplitude and excitation phase. If we can measure the reflector shape precisely in orbit, beam pattern and antenna performance can be compensated with the updated excitation amplitude and excitation phase parameters optimized for the reflector shape measured every moment. Softbank Corporation and National Institute of Information and Communications Technology has started the project "R&D on dynamic beam control technique for next generation mobile communication satellite" as a contracted research project sponsored by Ministry of Internal Affairs and Communication of Japan. In this topic, one of the problem in vision metrology application is a strong constraints on geometry for camera arrangement on satellite bus with very limited space. On satellite in orbit, we cannot take many images from many different directions as ordinary vision metrology measurement and the available area for camera positioning is quite limited. Feasibility of vision metrology application and general methodology to apply to future mobile satellite communication satellite is to be found. Our approach is as follows: 1) Development of prototyping simulator to evaluate the expected precision for network design in zero order and first order 2) Trial

  9. Proceedings of the 19th NASA Propagation Experimenters Meeting (NAPEX 19) and the 7th Advanced Communications Technology Satellite (ACTS) Propagation Studies Workshop (APSW 7)

    NASA Technical Reports Server (NTRS)

    Davarian, Faramaz (Editor)

    1995-01-01

    The NASA Propagation Experimenters Meeting (NAPEX), supported by the NASA Propagation Program, is convened annually to discuss studies made on radio wave propagation by investigators from domestic and international organizations. NAPEX 19 was held on 14 Jun. 1995, in Fort Collins, Colorado. Participants included representatives from Canada, Japan, and the United States, including researchers from universities, government agencies, and private industry. The meeting focused on mobile personal satellite systems and the use of 20/30-GHz band for fixed and mobile satellite applications. In total, 18 technical papers were presented. Following NAPEX 19, the Advanced Communications Technology Satellite (ACTS) Propagation Studies Workshop 7 (APSW 7) was held on 15-16 Jun. 1995, to review ACTS propagation activities with emphasis on the experimenters' status reports and dissemination of propagation data to industry.

  10. Netscape Communicator 4.5. Volume II: Beyond the Basics. Advanced Searches, Multimedia, and Composing a Web Page.

    ERIC Educational Resources Information Center

    Gallo, Gail; Wichowski, Chester P.

    This second of two guides on Netscape Communicator 4.5 contains six lessons on advanced searches, multimedia, and composing a World Wide Web page. Lesson 1 is a review of the Navigator window, toolbars, and menus. Lesson 2 covers AltaVista's advanced search tips, searching for information excluding certain text, and advanced and nested Boolean…

  11. Advancing the High Throughput Identification of Liver Fibrosis Protein Signatures Using Multiplexed Ion Mobility Spectrometry

    SciTech Connect

    Baker, Erin Shammel; Burnum-Johnson, Kristin E.; Jacobs, Jon M.; Diamond, Deborah L.; Brown, Roslyn N.; Ibrahim, Yehia M.; Orton, Daniel J.; Piehowski, Paul D.; Purdy, David E.; Moore, Ronald J.; Danielson, William F.; Monroe, Matthew E.; Crowell, Kevin L.; Slysz, Gordon W.; Gritsenko, Marina A.; Sandoval, John D.; Lamarche, Brian L.; Matzke, Melissa M.; Webb-Robertson, Bobbie-Jo M.; Simons, Brenna C.; McMahon, Brian J.; Bhattacharya, Renuka; Perkins, James D.; Carithers, Robert L.; Strom, Susan; Self, Steven; Katze, Michael G.; Anderson, Gordon A.; Smith, Richard D.

    2014-04-01

    Rapid diagnosis of disease states using less invasive, safer, and more clinically acceptable approaches than presently employed is an imperative goal for the field of medicine. While mass spectrometry (MS)-based proteomics approaches have attempted to meet these objectives, challenges such as the enormous dynamic range of protein concentrations in clinically relevant biofluid samples coupled with the need to address human biodiversity have slowed their employment. Herein, we report on the use of a new platform that addresses these challenges by coupling technical advances in rapid gas phase multiplexed ion mobility spectrometry (IMS) separations [1, 2] with liquid chromatography (LC) and MS to dramatically increase measurement sensitivity and throughput, further enabling future MS-based clinical applications. An initial application of the LC-IMS-MS platform for the analysis of blood serum samples from stratified post-liver transplant patients with recurrent fibrosis progression illustrates its potential utility for disease characterization and use in personalized medicine [3, 4].

  12. Proceedings of the Eleventh Advanced Communications Technology Satellite Propagation Studies Workshop (APSW 11)

    NASA Technical Reports Server (NTRS)

    Golshan, Nasser (Editor); Ho, Christian (Editor)

    1998-01-01

    The Advanced Communications Technology Satellite Propagation Studies Workshop (APSW) is convened each year to present the results of the Advanced Communications Technology Satellite (ACTS) Ka-band propagation campaign. Representatives from the space community including industry, academia, and government who are interested in radiowave propagation at Ka-band are invited to APSW for discussions and exchange of information. The ACTS Propagation campaign will complete five years of Ka-Band data collection at seven sites in North America by December 31, 1998. Through this effort, NASA is making a major contribution to the effective utilization of this band by providing timely propagation data and models for predicting the performance of Ka-band links between space and ground.

  13. All-digital multicarrier demodulators for on-board processing satellites in mobile communication systems

    NASA Astrophysics Data System (ADS)

    Yim, Wan Hung

    Economical operation of future satellite systems for mobile communications can only be fulfilled by using dedicated on-board processing satellites, which would allow both cheap earth terminals and lower space segment costs. With on-board modems and codecs, the up-link and down-link can be optimized separately. An attractive scheme is to use frequency-division multiple access/single chanel per carrier (FDMA/SCPC) on the up-link and time division multiplexing (TDM) on the down-link. This scheme allows mobile terminals to transmit a narrow band, low power signal, resulting in smaller dishes and high power amplifiers (HPA's) with lower output power. On the up-link, there are hundreds to thousands of FDM channels to be demodulated on-board. The most promising approach is the use of all-digital multicarrier demodulators (MCD's), where analog and digital hardware are efficiently shared among channels, and digital signal processing (DSP) is used at an early stage to take advantage of very large scale integration (VLSI) implementation. A MCD consists of a channellizer for separation of frequency division multiplexing (FDM) channels, followed by individual modulators for each channel. Major research areas in MCD's are in multirate DSP, and the optimal estimation for synchronization, which form the basis of the thesis. Complex signal theories are central to the development of structured approaches for the sampling and processing of bandpass signals, which are the foundations in both channellizer and demodulator design. In multirate DSP, polyphase theories replace many ad-hoc, tedious and error-prone design procedures. For example, a polyphase-matrix deep space network frequency and timing system (DFT) channellizer includes all efficient filter bank techniques as special cases. Also, a polyphase-lattice filter is derived, not only for sampling rate conversion, but also capable of sampling phase variation, which is required for symbol timing adjustment in all

  14. Mobile-ip Aeronautical Network Simulation Study

    NASA Technical Reports Server (NTRS)

    Ivancic, William D.; Tran, Diepchi T.

    2001-01-01

    NASA is interested in applying mobile Internet protocol (mobile-ip) technologies to its space and aeronautics programs. In particular, mobile-ip will play a major role in the Advanced Aeronautic Transportation Technology (AATT), the Weather Information Communication (WINCOMM), and the Small Aircraft Transportation System (SATS) aeronautics programs. This report presents the results of a simulation study of mobile-ip for an aeronautical network. The study was performed to determine the performance of the transmission control protocol (TCP) in a mobile-ip environment and to gain an understanding of how long delays, handoffs, and noisy channels affect mobile-ip performance.

  15. Towards Advancing Knowledge Translation of AAC Outcomes Research for Children and Youth with Complex Communication Needs.

    PubMed

    Ryan, Stephen E; Shepherd, Tracy; Renzoni, Anne Marie; Anderson, Colleen; Barber, Mary; Kingsnorth, Shauna; Ward, Karen

    2015-06-01

    The production of new knowledge in augmentative and alternative communication (AAC) requires effective processes to leverage the different perspectives of researchers and knowledge users and improve prospects for utilization in clinical settings. This article describes the motivation, planning, process, and outcomes for a novel knowledge translation workshop designed to influence future directions for AAC outcomes research for children with complex communication needs. Invited knowledge users from 20 pediatric AAC clinics and researchers engaged in the collaborative development of research questions using a framework designed for the AAC field. The event yielded recommendations for research and development priorities that extend from the early development of language, communication, and literacy skills in very young children, to novel but unproven strategies that may advance outcomes in transitioning to adulthood. PMID:25860836

  16. Mission science value-cost savings from the Advanced Imaging Communication System (AICS)

    NASA Technical Reports Server (NTRS)

    Rice, R. F.

    1984-01-01

    An Advanced Imaging Communication System (AICS) was proposed in the mid-1970s as an alternative to the Voyager data/communication system architecture. The AICS achieved virtually error free communication with little loss in the downlink data rate by concatenating a powerful Reed-Solomon block code with the Voyager convolutionally coded, Viterbi decoded downlink channel. The clean channel allowed AICS sophisticated adaptive data compression techniques. Both Voyager and the Galileo mission have implemented AICS components, and the concatenated channel itself is heading for international standardization. An analysis that assigns a dollar value/cost savings to AICS mission performance gains is presented. A conservative value or savings of $3 million for Voyager, $4.5 million for Galileo, and as much as $7 to 9.5 million per mission for future projects such as the proposed Mariner Mar 2 series is shown.

  17. Communication.

    ERIC Educational Resources Information Center

    Strauss, Andre

    The following essays on communication are presented: communication as a condition of survival, communication for special purposes, the means of transmission of communication, communication within social and economic structures, the teaching of communication through the press, the teaching of modern languages, communication as a point of departure,…

  18. Advanced Tie Feature Matching for the Registration of Mobile Mapping Imaging Data and Aerial Imagery

    NASA Astrophysics Data System (ADS)

    Jende, P.; Peter, M.; Gerke, M.; Vosselman, G.

    2016-06-01

    Mobile Mapping's ability to acquire high-resolution ground data is opposing unreliable localisation capabilities of satellite-based positioning systems in urban areas. Buildings shape canyons impeding a direct line-of-sight to navigation satellites resulting in a deficiency to accurately estimate the mobile platform's position. Consequently, acquired data products' positioning quality is considerably diminished. This issue has been widely addressed in the literature and research projects. However, a consistent compliance of sub-decimetre accuracy as well as a correction of errors in height remain unsolved. We propose a novel approach to enhance Mobile Mapping (MM) image orientation based on the utilisation of highly accurate orientation parameters derived from aerial imagery. In addition to that, the diminished exterior orientation parameters of the MM platform will be utilised as they enable the application of accurate matching techniques needed to derive reliable tie information. This tie information will then be used within an adjustment solution to correct affected MM data. This paper presents an advanced feature matching procedure as a prerequisite to the aforementioned orientation update. MM data is ortho-projected to gain a higher resemblance to aerial nadir data simplifying the images' geometry for matching. By utilising MM exterior orientation parameters, search windows may be used in conjunction with a selective keypoint detection and template matching. Originating from different sensor systems, however, difficulties arise with respect to changes in illumination, radiometry and a different original perspective. To respond to these challenges for feature detection, the procedure relies on detecting keypoints in only one image. Initial tests indicate a considerable improvement in comparison to classic detector/descriptor approaches in this particular matching scenario. This method leads to a significant reduction of outliers due to the limited availability

  19. Power and spectrally efficient M-ARY QAM schemes for future mobile satellite communications

    NASA Technical Reports Server (NTRS)

    Sreenath, K.; Feher, K.

    1990-01-01

    An effective method to compensate nonlinear phase distortion caused by the mobile amplifier is proposed. As a first step towards the future use of spectrally efficient modulation schemes for mobile satellite applications, we have investigated effects of nonlinearities and the phase compensation method on 16-QAM. The new method provides about 2 dB savings in power for 16-QAM operation with cost effective amplifiers near saturation and thereby promising use of spectrally efficient linear modulation schemes for future mobile satellite applications.

  20. Integration between terrestrial-based and satellite-based land mobile communications systems

    NASA Technical Reports Server (NTRS)

    Arcidiancono, Antonio

    1990-01-01

    A survey is given of several approaches to improving the performance and marketability of mobile satellite systems (MSS). The provision of voice/data services in the future regional European Land Mobile Satellite System (LMSS), network integration between the Digital Cellular Mobile System (GSM) and LMSS, the identification of critical areas for the implementation of integrated GSM/LMSS areas, space segment scenarios, LMSS for digital trunked private mobile radio (PMR) services, and code division multiple access (CDMA) techniques for a terrestrial/satellite system are covered.

  1. 41 CFR 302-10.300 - May I receive an advance of funds when a commercial carrier transports the mobile home?

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... of funds when a commercial carrier transports the mobile home? 302-10.300 Section 302-10.300 Public... STORAGE OF PROPERTY 10-ALLOWANCES FOR TRANSPORTATION OF MOBILE HOMES AND BOATS USED AS A PRIMARY RESIDENCE... mobile home? Yes, you may receive an advance of funds when you are responsible for arranging and paying...

  2. 41 CFR 302-10.300 - May I receive an advance of funds when a commercial carrier transports the mobile home?

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... of funds when a commercial carrier transports the mobile home? 302-10.300 Section 302-10.300 Public... STORAGE OF PROPERTY 10-ALLOWANCES FOR TRANSPORTATION OF MOBILE HOMES AND BOATS USED AS A PRIMARY RESIDENCE... mobile home? Yes, you may receive an advance of funds when you are responsible for arranging and paying...

  3. Interference of GSM mobile phones with communication between Cardiac Rhythm Management devices and programmers: A combined in vivo and in vitro study.

    PubMed

    Huang, Dong; Dong, Zhi-Feng; Chen, Yan; Wang, Fa-Bin; Wei, Zhi; Zhao, Wen-Bin; Li, Shuai; Liu, Ming-Ya; Zhu, Wei; Wei, Meng; Li, Jing-Bo

    2015-07-01

    To investigate interference, and how to avoid it, by high-frequency electromagnetic fields (EMFs) of Global System for Mobile Communications (GSM) mobile phone with communication between cardiac rhythm management devices (CRMs) and programmers, a combined in vivo and in vitro testing was conducted. During in vivo testing, GSM mobile phones interfered with CRM-programmer communication in 33 of 65 subjects tested (50.8%). Losing ventricle sensing was representative in this study. In terms of clinical symptoms, only 4 subjects (0.6%) felt dizzy during testing. CRM-programmer communication recovered upon termination of mobile phone communication. During in vitro testing, electromagnetic interference by high-frequency (700-950 MHz) EMFs reproducibly occurred in duplicate testing in 18 of 20 CRMs (90%). During each interference, the pacing pulse signal on the programmer would suddenly disappear while the synchronous signal was normal on the amplifier-oscilloscope. Simulation analysis showed that interference by radiofrequency emitting devices with CRM-programmer communication may be attributed to factors including materials, excitation source distance, and implant depth. Results suggested that patients implanted with CRMs should not be restricted from using GSM mobile phones; however, CRMs should be kept away from high-frequency EMFs of GSM mobile phone during programming. PMID:25864643

  4. Satellite-aided mobile radio concepts study: Concept definition of a satellite-aided mobile and personal radio communication system

    NASA Technical Reports Server (NTRS)

    Anderson, R. E.

    1979-01-01

    The satellite system requires the use of a large satellite antenna and spacecraft array power of about 12 kW or more depending on the operating frequency. Technology developments needed include large offset reflector multibeam antennas, satellite electrical power sybsystems providing greater than 12 kW of power, signal switching hardware, and linearized efficient solid state amplifiers for the satellite-aided mobile band. Presently there is no frequency assignment for this service, and it is recommended that an allocation be pursued. The satellite system appears to be within reasonable extrapolation of the state of the art. It is further recommended that the satellite-aided system spacecraft definition studies and supporting technology development be initiated.

  5. End-of-life communication in Korean older adults: With focus on advance care planning and advance directives.

    PubMed

    Shin, Dong Wook; Lee, Ji Eun; Cho, BeLong; Yoo, Sang Ho; Kim, SangYun; Yoo, Jun-Hyun

    2016-04-01

    The present article aimed to provide a comprehensive review of current status of end-of-life (EOL) care and sociocultural considerations in Korea, with focus on the EOL communication and use of advance directives (AD) in elderly Koreans. Through literature review, we discuss the current status of EOL care and sociocultural considerations in Korea, and provide a look-ahead. In Korea, patients often receive life-sustaining treatment until the very end of life. Advance care planning is rare, and most do-not-resuscitate decisions are made between the family and physician at the very end of patient's life. Koreans, influenced mainly by Confucian tradition, prefer a natural death and discontinuation of life-sustaining treatment. Although Koreans generally believe that death is natural and unavoidable, they tend not to think about or discuss death, and regard preparation for death as unnecessary. As a result, AD are completed by just 4.7% of the general adult population. This situation can be explained by several sociocultural characteristics including opting for natural death, wish not to burden others, preference for family involvement and trust in doctor, avoidance of talking about death, and filial piety. Patients often receive life-sustaining treatment until the very EOL, advance care planning and the use of AD is not common in Korea. This was related to unique sociocultural characteristics of Korea. A more active role of physicians, development of a more deliberate EOL discussion process, development of culturally appropriate AD and promotion of advance care planning might be required to provide good EOL care in Korea. PMID:26459613

  6. Short communication: Genetic evaluation of mobility for Brown Swiss dairy cattle

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Genetic parameters were estimated for mobility score and 16 linear type traits of Brown Swiss dairy cattle. Mobility is an overall assessment trait that measures a cow’s ability to move as well as the structure of her feet, pasterns, and legs. Scores from 50 to 99 were assigned by appraisers for the...

  7. Spreading the Load: Mobile Information and Communications Technologies and Their Effect on Information Overload

    ERIC Educational Resources Information Center

    Allen, David K.; Shoard, M.

    2005-01-01

    Introduction: We report on a small-scale research project which examined the impact of mobile technologies on the users' experience of information overload. The project focused on a group of worker who have had relatively little attention in both the mobile technology and information overload literatures: senior managers. Method: The case study…

  8. Advances in high-throughput speed, low-latency communication for embedded instrumentation ( 7th Annual SFAF Meeting, 2012)

    ScienceCinema

    Jordan, Scott [Physik Instrumente

    2013-02-11

    Scott Jordan on "Advances in high-throughput speed, low-latency communication for embedded instrumentation" at the 2012 Sequencing, Finishing, Analysis in the Future Meeting held June 5-7, 2012 in Santa Fe, New Mexico.

  9. Advances in high-throughput speed, low-latency communication for embedded instrumentation ( 7th Annual SFAF Meeting, 2012)

    SciTech Connect

    Jordan, Scott

    2012-06-01

    Scott Jordan on "Advances in high-throughput speed, low-latency communication for embedded instrumentation" at the 2012 Sequencing, Finishing, Analysis in the Future Meeting held June 5-7, 2012 in Santa Fe, New Mexico.

  10. Mobile Wireless Sensor Networks for Advanced Soil Sensing and Ecosystem Monitoring

    NASA Astrophysics Data System (ADS)

    Mollenhauer, Hannes; Schima, Robert; Remmler, Paul; Mollenhauer, Olaf; Hutschenreuther, Tino; Toepfer, Hannes; Dietrich, Peter; Bumberger, Jan

    2015-04-01

    For an adequate characterization of ecosystems it is necessary to detect individual processes with suitable monitoring strategies and methods. Due to the natural complexity of all environmental compartments, single point or temporally and spatially fixed measurements are mostly insufficient for an adequate representation. The application of mobile wireless sensor networks for soil and atmosphere sensing offers significant benefits, due to the simple adjustment of the sensor distribution, the sensor types and the sample rate (e.g. by using optimization approaches or event triggering modes) to the local test conditions. This can be essential for the monitoring of heterogeneous and dynamic environmental systems and processes. One significant advantage in the application of mobile ad-hoc wireless sensor networks is their self-organizing behavior. Thus, the network autonomously initializes and optimizes itself. Due to the localization via satellite a major reduction in installation and operation costs and time is generated. In addition, single point measurements with a sensor are significantly improved by measuring at several optimized points continuously. Since performing analog and digital signal processing and computation in the sensor nodes close to the sensors a significant reduction of the data to be transmitted can be achieved which leads to a better energy management of nodes. Furthermore, the miniaturization of the nodes and energy harvesting are current topics under investigation. First results of field measurements are given to present the potentials and limitations of this application in environmental science. In particular, collected in-situ data with numerous specific soil and atmosphere parameters per sensor node (more than 25) recorded over several days illustrates the high performance of this system for advanced soil sensing and soil-atmosphere interaction monitoring. Moreover, investigations of biotic and abiotic process interactions and optimization

  11. Advancing Mobile Learning in Formal and Informal Settings via Mobile App Technology: Where to from Here, and How?

    ERIC Educational Resources Information Center

    Khaddage, Ferial; Müller, Wolfgang; Flintoff, Kim

    2016-01-01

    In this paper a brief review of the framework that addressed mobile learning implementation challenges (pedagogical, technological, policy and research) that was developed by Khaddage et al. (2015) is briefly discussed, followed by possible solutions that could be deployed to tackle those challenges. A unique approach is then applied to bridge the…

  12. A highly reliable, autonomous data communication subsystem for an advanced information processing system

    NASA Technical Reports Server (NTRS)

    Nagle, Gail; Masotto, Thomas; Alger, Linda

    1990-01-01

    The need to meet the stringent performance and reliability requirements of advanced avionics systems has frequently led to implementations which are tailored to a specific application and are therefore difficult to modify or extend. Furthermore, many integrated flight critical systems are input/output intensive. By using a design methodology which customizes the input/output mechanism for each new application, the cost of implementing new systems becomes prohibitively expensive. One solution to this dilemma is to design computer systems and input/output subsystems which are general purpose, but which can be easily configured to support the needs of a specific application. The Advanced Information Processing System (AIPS), currently under development has these characteristics. The design and implementation of the prototype I/O communication system for AIPS is described. AIPS addresses reliability issues related to data communications by the use of reconfigurable I/O networks. When a fault or damage event occurs, communication is restored to functioning parts of the network and the failed or damage components are isolated. Performance issues are addressed by using a parallelized computer architecture which decouples Input/Output (I/O) redundancy management and I/O processing from the computational stream of an application. The autonomous nature of the system derives from the highly automated and independent manner in which I/O transactions are conducted for the application as well as from the fact that the hardware redundancy management is entirely transparent to the application.

  13. Manufacturing consent?: Media messages in the mobilization against HIV/AIDS in India and lessons for health communication.

    PubMed

    Khan, Shamshad

    2014-01-01

    Despite repeated calls for a more critical and "culture-centered" approach to health communication, textual analysis of televised public service advertising (PSA) campaigns has been largely neglected, even by critical communication scholars. In the case of "developing" countries in particular, there is an acute shortage of such literature. On the other hand, following the outbreak of major public health diseases such as AIDS, most countries have adopted PSA campaigns as the most preferred means of communicating messages. Drawing on insights from cultural studies (especially Antonio Gramsci and Stuart Hall), this article engages in textual analysis of the televised PSA campaigns launched by the Indian state to prevent HIV/AIDS between 2002 and 2005. Through such analysis, it argues that although few diseases in Indian history have spurred such massive and creative efforts for mass mobilization as AIDS, these efforts, in terms of their ethical implications, have been far from emancipatory. In fact, they have constructed and perpetuated the logic of domination and control along class, gender, sexuality, and knowledge systems, often contradicting and potentially harming the very goal of HIV prevention and of health promotion and empowerment. This article also holds that assessing public health campaigns through textual analysis, a highly neglected tool in health communication, can shed important light on a far more complex and changing nature of the state and public policy, especially in the developing world, thereby opening up space for alternative theorizing for health communication and social change. PMID:23631645

  14. Initial experience with a handheld device digital imaging and communications in medicine viewer: OsiriX mobile on the iPhone.

    PubMed

    Choudhri, Asim F; Radvany, Martin G

    2011-04-01

    Medical imaging is commonly used to diagnose many emergent conditions, as well as plan treatment. Digital images can be reviewed on almost any computing platform. Modern mobile phones and handheld devices are portable computing platforms with robust software programming interfaces, powerful processors, and high-resolution displays. OsiriX mobile, a new Digital Imaging and Communications in Medicine viewing program, is available for the iPhone/iPod touch platform. This raises the possibility of mobile review of diagnostic medical images to expedite diagnosis and treatment planning using a commercial off the shelf solution, facilitating communication among radiologists and referring clinicians. PMID:20567992

  15. The Impact of the Advancing Social-Communication and Play (ASAP) Intervention on Preschoolers with Autism Spectrum Disorder

    ERIC Educational Resources Information Center

    Dykstra, Jessica R.; Boyd, Brian A.; Watson, Linda R.; Crais, Elizabeth R.; Baranek, Grace T.

    2012-01-01

    This study evaluates an intervention targeting social-communication and play skills (Advancing Social-communication And Play; ASAP) implemented by school staff in a public preschool setting. With increases in enrollment of children with autism spectrum disorder (ASD) in school systems, establishing the effectiveness and feasibility of…

  16. The Impact of the Advancing Social-Communication and Play (ASAP) Intervention on Preschoolers with Autism Spectrum Disorder

    ERIC Educational Resources Information Center

    Dykstra, Jessica R.; Boyd, Brian A.; Watson, Linda R.; Crais, Elizabeth R.; Baranek, Grace T.

    2012-01-01

    This study evaluates an intervention targeting social-communication and play skills (Advancing Social-communication and Play; ASAP) implemented by school staff in a public preschool setting. With increases in enrollment of children with autism spectrum disorder (ASD) in school systems, establishing the effectiveness and feasibility of…

  17. Field testing of a remote controlled robotic tele-echo system in an ambulance using broadband mobile communication technology.

    PubMed

    Takeuchi, Ryohei; Harada, Hiroshi; Masuda, Kohji; Ota, Gen-ichiro; Yokoi, Masaki; Teramura, Nobuyasu; Saito, Tomoyuki

    2008-06-01

    We report the testing of a mobile Robotic Tele-echo system that was placed in an ambulance and successfully transmitted clear real time echo imaging of a patient's abdomen to the destination hospital from where this device was being remotely operated. Two-way communication between the paramedics in this vehicle and a doctor standing by at the hospital was undertaken. The robot was equipped with an ultrasound probe which was remotely controlled by the clinician at the hospital and ultrasound images of the patient were transmitted wirelessly. The quality of the ultrasound images that were transmitted over the public mobile telephone networks and those transmitted over the Multimedia Wireless Access Network (a private networks) were compared. The transmission rate over the public networks and the private networks was approximately 256 Kbps, 3 Mbps respectively. Our results indicate that ultrasound images of far higher definition could be obtained through the private networks. PMID:18444361

  18. Advanced driver assistance system for AHS over communication links with random packet dropouts

    NASA Astrophysics Data System (ADS)

    Srinivasan, Seshadhri; Ayyagari, Ramakalyan

    2014-12-01

    In this paper, we propose an advanced driver assist system (ADAS) for platoon based automated highway system (AHS) with packet loss in inter-vehicle communication. Using the concept of rigidity, we first show that vehicles in a platoon tend to fall apart in the event of a packet loss among vehicles. To overcome this, we propose an estimation based dynamic platooning algorithm which employs the state estimate to maintain the platoon. Communication among the vehicle is reduced by using minimum spanning tree (MST) in state estimation algorithm. Effectiveness of the proposed ADAS scheme is illustrated by simulation wherein, dynamic platoons of holonomic vehicles with integrator dynamics are considered. Simulation studies indicate that the proposed algorithm maintains the platoon up to a packet loss rate of 48%. State transmission scheme proposed in our algorithm has three significant advantages, they are: (1) it handles packet loss in inter-vehicle communication, (2) reduces the effect of error in measured output, and (3) reduces the inter-vehicle communication. These advantages significantly increase the reliability and safety of the AHS.

  19. Advanced Communication Technology Satellite (ACTS) Very Small Aperture Terminal (VSAT) Network Control Performance

    NASA Technical Reports Server (NTRS)

    Coney, T. A.

    1996-01-01

    This paper discusses the performance of the network control function for the Advanced Communications Technology Satellite (ACTS) very small aperture terminal (VSAT) full mesh network. This includes control of all operational activities such as acquisition, synchronization, timing and rain fade compensation as well as control of all communications activities such as on-demand integrated services (voice, video, and date) connects and disconnects Operations control is provided by an in-band orderwire carried in the baseboard processor (BBP) control burst, the orderwire burst, the reference burst, and the uplink traffic burst. Communication services are provided by demand assigned multiple access (DAMA) protocols. The ACTS implementation of DAMA protocols ensures both on-demand and integrated voice, video and data services. Communications services control is also provided by the in-band orderwire but uses only the reference burst and the uplink traffic burst. The performance of the ACTS network control functions have been successfully tested during on-orbit checkout and in various VSAT networks in day to day operations. This paper discusses the network operations and services control performance.

  20. Advances in Ka-Band Communication System for CubeSats and SmallSats

    NASA Technical Reports Server (NTRS)

    Kegege, Obadiah; Wong, Yen F.; Altunc, Serhat

    2016-01-01

    A study was performed that evaluated the feasibility of Ka-band communication system to provide CubeSat/SmallSat high rate science data downlink with ground antennas ranging from the small portable 1.2m/2.4m to apertures 5.4M, 7.3M, 11M, and 18M, for Low Earth Orbit (LEO) to Lunar CubeSat missions. This study included link analysis to determine the data rate requirement, based on the current TRL of Ka-band flight hardware and ground support infrastructure. Recent advances in Ka-band transceivers and antennas, options of portable ground stations, and various coverage distances were included in the analysis. The link/coverage analysis results show that Cubesat/Smallsat missions communication requirements including frequencies and data rates can be met by utilizing Near Earth Network (NEN) Ka-band support with 2 W and high gain (>6 dBi) antennas.

  1. CCSDS Advanced Orbiting Systems - International data communications standards for the Space Station Freedom

    NASA Technical Reports Server (NTRS)

    Hooke, Adrian J.

    1990-01-01

    Established in 1982, the Consultative Committee for Space Data Systems (CCSDS) is an international organization that is staffed by data-handling experts from nearly all of the world's major space agencies. Its goal is to develop standard data-communications techniques so that several agencies may cross-support each other's data flow and thus allow complex, international missions to be flown. Under the general umbrella of Advanced Orbiting Systems (AOS), an international CCSDS task force was formed in 1985 to develop standard data-communications concepts for manned missions, such as the Space Station Freedom and the Hermes space plane, and large unmanned vehicles, such as polar orbiting platforms. The history of the CCSDS and the development of the AOS recommendation are reviewed, and the user services and protocols embodied in its systems architecture are introduced.

  2. Application of Mobile-ip to Space and Aeronautical Networks

    NASA Technical Reports Server (NTRS)

    Leung, Kent; Shell, Dan; Ivancic, William D.; Stewart, David H.; Bell, Terry L.; Kachmar, Brian A.

    2001-01-01

    The National Aeronautics and Space Administration (NASA) is interested in applying mobile Internet protocol (mobile-ip) technologies to its space and aeronautics programs. In particular, mobile-ip will play a major role in the Advanced Aeronautic Transportation Technology (AAT-F), the Weather Information Communication (WINCOMM), and the Small Aircraft Transportation System (SATS) aeronautics programs. This paper describes mobile-ip and mobile routers--in particular, the features, capabilities, and initial performance of the mobile router are presented. The application of mobile-router technology to NASA's space and aeronautics programs is also discussed.

  3. Advancing Ethics Frameworks and Scenario-Based Learning to Support Educational Research into Mobile Learning

    ERIC Educational Resources Information Center

    Andrews, Trish; Dyson, Laurel Evelyn; Wishart, Jocelyn

    2015-01-01

    The ubiquity of mobile devices and their use for collecting and sharing data require a reconsideration of approaches taken to managing ethical concerns in the educational research context. In the mobile age, the concept of educational research extends beyond traditional understandings and contexts due to: the wide range of mobile learning research…

  4. Communication satellite technology trends

    NASA Technical Reports Server (NTRS)

    Cuccia, Louis

    1986-01-01

    A chronology of space-Earth interconnectivity is presented. The Advanced Communications Technology Satellite (ACTS) system, Land Mobile Satellite, space-Earth antennas, impact of antenna size on coverage, intersatellite links are outlined. This presentation is represented by graphs and charts only.

  5. Emerging Communication Technologies (ECT) Phase 4 Report

    NASA Technical Reports Server (NTRS)

    Bastin, Gary L.; Harris, William G.; Marin, Jose A.; Nelson, Richard A.

    2005-01-01

    The Emerging Communication Technology (ECT) project investigated three First Mile communication technologies in support of NASA s Crew Exploration Vehicle (CEV), Advanced Range Technology Working Group (ARTWG), and the Advanced Spaceport Technology Working Group (ASTWG). These First Mile technologies have the purpose of interconnecting mobile users with existing Range Communication infrastructures on a 24/7 basis. ECT is a continuation of the Range Information System Management (RISM) task started in 2002. This is the fourth year of the project.

  6. An infrastructure for cooperation and communication in an advanced clinical information system.

    PubMed Central

    Kuhn, K.; Reichert, M.; Nathe, M.; Beuter, T.; Dadam, P.

    1994-01-01

    In a research project, organizational and technological requirements for an advanced clinical information system have been analysed, and a concept has been developed. From the application's perspective, medical personnel is more actively relieved from routine tasks by support of organizational tasks and by coordination of distributed activities. Program development is supported by a concept of simple and complex services with well-defined interfaces, and by the use of activity templates, i.e. pre-modeled activities describing possible sequences of services. The concept is based on an open systems approach, with a reliable and secure communication infrastructure. In addition, monitoring facilities are provided. PMID:7949982

  7. Advanced digital modulation: Communication techniques and monolithic GaAs technology

    NASA Technical Reports Server (NTRS)

    Wilson, S. G.; Oliver, J. D., Jr.; Kot, R. C.; Richards, C. R.

    1983-01-01

    Communications theory and practice are merged with state-of-the-art technology in IC fabrication, especially monolithic GaAs technology, to examine the general feasibility of a number of advanced technology digital transmission systems. Satellite-channel models with (1) superior throughput, perhaps 2 Gbps; (2) attractive weight and cost; and (3) high RF power and spectrum efficiency are discussed. Transmission techniques possessing reasonably simple architectures capable of monolithic fabrication at high speeds were surveyed. This included a review of amplitude/phase shift keying (APSK) techniques and the continuous-phase-modulation (CPM) methods, of which MSK represents the simplest case.

  8. High-speed image transmission via the Advanced Communication Technology Satellite (ACTS)

    NASA Astrophysics Data System (ADS)

    Bazzill, Todd M.; Huang, H. K.; Thoma, George R.; Long, L. Rodney; Gill, Michael J.

    1996-05-01

    We are developing a wide area test bed network using the Advanced Communication Technology Satellite (ACTS) from NASA for high speed medical image transmission. The two test sites are the University of California, San Francisco, and the National Library of Medicine. The first phase of the test bed runs over a T1 link (1.544 Mbits/sec) using a Very Small Aperture Terminal. The second phase involves the High Data Rate Terminal via an ATM OC 3C (155 Mbits/sec) connection. This paper describes the experimental set up and some preliminary results from phase 1.

  9. Communicating with patients who have advanced dementia: training nurse aide students.

    PubMed

    Beer, Laura E; Hutchinson, Susan R; Skala-Cordes, Kristine K

    2012-01-01

    The increase of dementia in older adults is changing how medical care is delivered. Recognizing symptoms of pain, managing behaviors, and providing quality of life for people who have advanced dementia requires a new skill set for caregivers. Researchers in this study targeted nurse aide students to test an educational module's effect on students' perceptions of dementia and their ability to care for patients with dementia. The results indicated the training was effective regarding nurse aides' understanding of residual cognitive abilities and need for meaningful contact among patients with advanced dementia; however, the training was not successful in terms of nurse aides' comfort level or perceived skills in working with this population of patients. The findings suggest a need to transform how caregivers are trained in communication techniques. Incorporating this training into nurse aide education has the potential to increase quality of life for people with dementia. PMID:23095223

  10. Enhancing Extemporaneous Speaking Skills in the Advanced Oral Communication Course and Team Testing Techniques in the Basic Course.

    ERIC Educational Resources Information Center

    Reppert, James E.

    In an advanced oral communication course, students make five major presentations. One of the foundations of extemporaneous speaking is the ability to outline relevant points and phrases in a coherent, orderly manner. Advanced students must be able to take any topic and dissect it quickly to determine the most succinct way to present it to an…

  11. A geostationary satellite system for mobile multimedia applications using portable, aeronautical and mobile terminals

    NASA Technical Reports Server (NTRS)

    Losquadro, G.; Luglio, M.; Vatalaro, F.

    1997-01-01

    A geostationary satellite system for mobile multimedia services via portable, aeronautical and mobile terminals was developed within the framework of the Advanced Communications Technology Service (ACTS) programs. The architecture of the system developed under the 'satellite extremely high frequency communications for multimedia mobile services (SECOMS)/ACTS broadband aeronautical terminal experiment' (ABATE) project is presented. The system will be composed of a Ka band system component, and an extremely high frequency band component. The major characteristics of the space segment, the ground control station and the portable, aeronautical and mobile user terminals are outlined.

  12. Advance Directives and Communication Skills of Prehospital Physicians Involved in the Care of Cardiovascular Patients.

    PubMed

    Gigon, Fabienne; Merlani, Paolo; Ricou, Bara

    2015-12-01

    Advance directives (AD) were developed to respect patient autonomy. However, very few patients have AD, even in cases when major cardiovascular surgery is to follow. To understand the reasons behind the low prevalence of AD and to help decision making when patients are incompetent, it is necessary to focus on the impact of prehospital practitioners, who may contribute to an increase in AD by discussing them with patients. The purpose of this study was to investigate self-rated communication skills and the attitudes of physicians potentially involved in the care of cardiovascular patients toward AD.Self-administered questionnaires were sent to general practitioners, cardiologists, internists, and intensivists, including the Quality of Communication Score, divided into a General Communication score (QOCgen 6 items) and an End-of-life Communication score (QOCeol 7 items), as well as questions regarding opinions and practices in terms of AD.One hundred sixty-four responses were received. QOCgen (mean (±SD)): 9.0/10 (1.0); QOCeol: 7.2/10 (1.7). General practitioners most frequently start discussions about AD (74/149 [47%]) and are more prone to designate their own specialty (30/49 [61%], P < 0.0001). Overall, only 57/159 (36%) physicians designated their own specialty; 130/158 (82%) physicians ask potential cardiovascular patients if they have AD and 61/118 (52%) physicians who care for cardiovascular patients talk about AD with some of them.The characteristics of physicians who do not talk about AD with patients were those who did not personally have AD and those who work in private practices.One hundred thirty-three (83%) physicians rated the systematic mention of patients' AD in the correspondence between physicians as good, while 114 (71%) at the patients' first registration in the private practice.Prehospital physicians rated their communication skills as good, whereas end-of-life communication was rated much lower. Only half of those surveyed speak about AD

  13. The use of advanced tracking technologies for the analysis of mobility in Alzheimer's disease and related cognitive diseases

    PubMed Central

    Shoval, Noam; Auslander, Gail K; Freytag, Tim; Landau, Ruth; Oswald, Frank; Seidl, Ulrich; Wahl, Hans-Werner; Werner, Shirli; Heinik, Jeremia

    2008-01-01

    Background One of the more common behavioral manifestations of dementia-related disorders is severe problems with out-of-home mobility. Various efforts have been attempted to attain a better understanding of mobility behavior, but most studies are based on institutionalized patients and the assessment usually relies on reports of caregivers and institutional staff, using observational approaches, activity monitoring, or behavioral checklists. The current manuscript describes the research protocol of a project that measures mobility in Alzheimer's disease and related cognitive disorders in an innovative way, by taking advantage of advanced tracking technologies. Methods/design Participants are 360 demented persons, mildly cognitively impaired persons, and unimpaired controls aged ≥ 65 in Israel and Germany. Data regarding space-time activities will be collected via a GPS tracking kit for a period of 4 weeks in 3 waves (one year apart) with the same participants (using a repeated measures design). Participants will be interviewed by use of a battery of instruments prior to and following GPS data collection. Further, a family member will complete a questionnaire both before and after data tracking. Statistical analyses will strive to explain differences in mobility based on a wide range of socio-structural, clinical, affect-related and environmental variables. We will also assess the impact of the use of advanced tracking technology on the quality of life of dementia patients and care givers, as well as its potential as a diagnostic tool. Systematic assessment of ethical issues involved in the use of tracking technology will be an integral component of the project. Discussion This project will be able to make a substantial contribution to basic as well as applied and clinical aspects in the area of mobility and cognitive impairment research. The innovative technologies applied in this study will allow for assessing a range of dimensions of out-of-home mobility, and

  14. An advanced Ka band phased array communication system at commercial frequencies

    NASA Astrophysics Data System (ADS)

    Wald, Lawrence; Kacpura, Thomas; Kershner, Dennis

    2000-01-01

    The Glenn Research Center (GRC) Direct Data Distribution (D3) project will demonstrate an advanced, high-performance communication system that transmits information from a technology payload carried by the Space Shuttle in low-Earth orbit (LEO) to a small receiving terminal on the Earth. The Shuttle-based communications package will utilize a solid-state, Ka-band phased array antenna that electronically steers the 19.05 Ghz RF signal toward a low-cost, tracking ground terminal, thereby providing agile, vibration-free, electronic steering at reduced size and weight with increased reliability. The project will also demonstrate new digital modulation and processing technology that will allow transmission of user/platform data at rates up to 1200 Mbits per second. This capability will enable the management of the substantially increased amounts of data to be collected from the International Space Station (ISS) or other LEO platforms directly to NASA field centers, principal investigators, or into the commercial terrestrial communications network. .

  15. Advances in automated deception detection in text-based computer-mediated communication

    NASA Astrophysics Data System (ADS)

    Adkins, Mark; Twitchell, Douglas P.; Burgoon, Judee K.; Nunamaker, Jay F., Jr.

    2004-08-01

    The Internet has provided criminals, terrorists, spies, and other threats to national security a means of communication. At the same time it also provides for the possibility of detecting and tracking their deceptive communication. Recent advances in natural language processing, machine learning and deception research have created an environment where automated and semi-automated deception detection of text-based computer-mediated communication (CMC, e.g. email, chat, instant messaging) is a reachable goal. This paper reviews two methods for discriminating between deceptive and non-deceptive messages in CMC. First, Document Feature Mining uses document features or cues in CMC messages combined with machine learning techniques to classify messages according to their deceptive potential. The method, which is most useful in asynchronous applications, also allows for the visualization of potential deception cues in CMC messages. Second, Speech Act Profiling, a method for quantifying and visualizing synchronous CMC, has shown promise in aiding deception detection. The methods may be combined and are intended to be a part of a suite of tools for automating deception detection.

  16. Access to Mobile Communication Technology and Willingness to Participate in Automated Telemedicine Calls Among Chronically Ill Patients in Honduras

    PubMed Central

    Mendoza-Avelares, Milton O.; Milton, Evan C.; Lange, Ilta; Fajardo, Roosevelt

    2010-01-01

    Abstract Objectives: Patients in underdeveloped countries may be left behind by advances in telehealthcare. We surveyed chronically ill patients with low incomes in Honduras to measure their use of mobile technologies and willingness to participate in mobile disease management support. Materials and Methods: 624 chronically ill primary care patients in Honduras were surveyed. We examined variation in telephone access across groups defined by patients' sociodemographic characteristics, diagnoses, and access to care. Logistic regression was used to identify independent correlates of patients' interest in automated telephonic support for disease management. Results: Participants had limited education (mean 4.8 years), and 65% were unemployed. Eighty-four percent had telephone access, and 78% had cell phones. Most respondents had voicemail (61%) and text messaging (58%). Mobile technologies were particularly common among patients who had to forego clinic visits and medications due to cost concerns (each p < 0.05). Most patients (>80%) reported that they would be willing to receive automated calls focused on appointment reminders, medication adherence, health status monitoring, and self-care education. Patients were more likely to be willing to participate in automated telemedicine services if they had to cancel a clinic appointment due to transportation problems or forego medication due to cost pressures. Conclusions: Even in this poor region of Honduras, most chronically ill patients have access to mobile technology, and most are willing to participate in automated telephone disease management support. Given barriers to in-person care, new models of mobile healthcare should be developed for chronically ill patients in developing countries. PMID:21062234

  17. Application of mobile digital communications in law enforcement, an introductory planning guide

    NASA Technical Reports Server (NTRS)

    Sohn, R. L.; Abraham, J. E.; Leflang, W. G.; Kennedy, R. D.; Wilson, J. H.; Gurfield, R. M.

    1975-01-01

    A set of planning guidelines for the application of digital communications techniques to law enforcement use is presented. Some essential characteristics of digital techniques and their applications are outlined, as are some principles of system analysis, evaluation, and planning. Requirements analysis, system concept design, implementation planning, and performance and cost modeling are described and demonstrated with respect to this application problem. Information on law enforcement digital communications systems and equipment and a list of vendor sources are given in appendices.

  18. Patients' perceptions and experiences of using a mobile phone-based advanced symptom management system (ASyMS) to monitor and manage chemotherapy related toxicity.

    PubMed

    McCann, L; Maguire, R; Miller, M; Kearney, N

    2009-03-01

    Chemotherapy forms a core component of treatment for the majority patients with cancer. Recent changes in cancer services mean patients frequently receive such treatment as outpatients and are often required to manage side effects at home without direct support from oncology health professionals. Information technology continues to develop to support patients in the community; this study evaluated the impact of a mobile phone-based advanced symptom management system (ASyMS) on chemotherapy related toxicity in patients with lung, breast or colorectal cancer. One hundred and twelve patients were randomized from seven clinical sites across the UK; 56 patients used the mobile phone to record their symptoms, sending their reports directly to the nurses at their clinical site; 56 control group patients received standard care. Health professionals were alerted about any severe or life-threatening symptoms through the development of a chemotherapy symptom risk model. Patients' perceptions of ASyMS were evaluated pre and post participation. Patients reported many benefits of using ASyMS including improved communication with health professionals, improvements in the management of their symptoms, and feeling reassured their symptoms were being monitored while at home. ASyMS has the potential to positively impact on the management of symptoms in patients receiving chemotherapy treatment. PMID:19267731

  19. How Oncologists and Their Patients with Advanced Cancer Communicate about Health-Related Quality of Life

    PubMed Central

    Rodriguez, Keri L.; Bayliss, Nichole; Alexander, Stewart C.; Jeffreys, Amy S.; Olsen, Maren K.; Pollak, Kathryn I.; Kennifer, Sarah L.; Tulsky, James A.; Arnold, Robert M.

    2011-01-01

    Objective To describe the content and frequency of communication about health-related quality of life (HRQOL) during outpatient encounters between oncologists and their patients with advanced cancer. Methods We coded for HRQOL talk in a subset of audio recorded conversations (each previously found to contain prognostic talk by the oncologist) from the Study of Communication in Oncologist-Patient Encounters (SCOPE) Trial, a randomized controlled trial conducted from 2003 to 2008 in two large U.S. academic medical centers and one Veterans Affairs Medical Center. Results Seventy-three encounters that involved 70 patients and 37 oncologists. Patients were more likely to be female (53%), white (86%), married (78%), and possessing some college education (62%). Most oncologists were male (78%) and white (78%). Mean ages were 59 years for patients and 44 years for oncologists. Every encounter included some talk about HRQOL and HRQOL discussions made up, on average, 25% of the visit time. HRQOL segments described symptoms (50%); general HRQOL (27%); and the following concerns: physical (27%), functional (22%), psychological (9%), social (7%), spiritual (1%), and other (28%). Topics included treatment (56%), disease (14%), and testing (3%), and conversations focused on past (44%), present (68%), and future HRQOL (59%). Conclusions HRQOL discussions between oncologists and patients are common, but the emphasis is often on treatment (e.g., side effects) and symptoms (e.g., pain) even in patients with advanced disease. Given the often intense emotional experience of patients with advanced cancer, oncologists may need to pay more attention to psychological, social, and spiritual HRQOL concerns. PMID:19449348

  20. Next-Generation Evaporative Cooling Systems for the Advanced Extravehicular Mobility Unit Portable Life Support System

    NASA Technical Reports Server (NTRS)

    Makinen, Janice V.; Anchondo, Ian; Bue, Grant C.; Campbell, Colin; Colunga, Aaron

    2012-01-01

    The development of the Advanced Extravehicular Mobility Unit (AEMU) Portable Life Support System (PLSS) is currently underway at NASA Johnson Space Center. The AEMU PLSS features two new evaporative cooling systems, the Reduced Volume Prototype Spacesuit Water Membrane Evaporator (RVP SWME), and the Auxiliary Cooling Loop (ACL). The RVP SWME is the third generation of hollow fiber SWME hardware, and like its predecessors, RVP SWME provides nominal crewmember and electronics cooling by flowing water through porous hollow fibers. Water vapor escapes through the hollow fiber pores, thereby cooling the liquid water that remains inside of the fibers. This cooled water is then recirculated to remove heat from the crewmember and PLSS electronics. Major design improvements, including a 36% reduction in volume, reduced weight, and more flight like back-pressure valve, facilitate the packaging of RVP SWME in the AEMU PLSS envelope. In addition to the RVP SWME, the Auxiliary Cooling Loop (ACL), was developed for contingency crewmember cooling. The ACL is a completely redundant, independent cooling system that consists of a small evaporative cooler--the Mini Membrane Evaporator (Mini-ME), independent pump, independent feed-water assembly and independent Liquid Cooling Garment (LCG). The Mini-ME utilizes the same hollow fiber technology featured in the RVP SWME, but is only 25% of the size of RVP SWME, providing only the necessary crewmember cooling in a contingency situation. The ACL provides a number of benefits when compared with the current EMU PLSS contingency cooling technology; contingency crewmember cooling can be provided for a longer period of time, more contingency situations can be accounted for, no reliance on a Secondary Oxygen Vessel (SOV) for contingency cooling--thereby allowing a SOV reduction in size and pressure, and the ACL can be recharged-allowing the AEMU PLSS to be reused, even after a contingency event. The development of these evaporative cooling

  1. Maintaining Adequate Carbon Dioxide Washout for an Advanced Extravehicular Mobility Unit

    NASA Technical Reports Server (NTRS)

    Chullen, Cinda; Navarro, Moses; Conger, Bruce; Korona, Adam; McMillin, Summer; Norcross, Jason; Swickrath, Mike

    2013-01-01

    Over the past several years, NASA has realized tremendous progress in technology development that is aimed at the production of an Advanced Extravehicular Mobility Unit (AEMU). Of the many functions provided by the spacesuit and portable life support subsystem within the AEMU, delivering breathing gas to the astronaut along with removing the carbon dioxide (CO2) remains one of the most important environmental functions that the AEMU can control. Carbon dioxide washout is the capability of the ventilation flow in the spacesuit helmet to provide low concentrations of CO2 to the crew member to meet breathing requirements. CO2 washout performance is a critical parameter needed to ensure proper and sufficient designs in a spacesuit and in vehicle applications such as sleep stations and hygiene compartments. Human testing to fully evaluate and validate CO2 washout performance is necessary but also expensive due to the levied safety requirements. Moreover, correlation of math models becomes challenging because of human variability and movement. To supplement human CO2 washout testing, a breathing capability will be integrated into a suited manikin test apparatus to provide a safe, lower cost, stable, easily modeled alternative to human testing. Additionally, this configuration provides NASA Johnson Space Center (JSC) the capability to evaluate CO2 washout under off-nominal conditions that would otherwise be unsafe for human testing or difficult due to fatigue of a test subject. Testing has been under way in-house at JSC and analysis has been initiated to evaluate whether the technology provides sufficient performance in ensuring that the CO2 is removed sufficiently and the ventilation flow is adequate for maintaining CO2 washout in the AEMU spacesuit helmet of the crew member during an extravehicular activity. This paper will review recent CO2 washout testing and analysis activities, testing planned in-house with a spacesuit simulator, and the associated analytical work

  2. 75 FR 63445 - Vessel Monitoring Systems; Approved Mobile Transmitting Units and Communications Service...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-10-15

    .... SUPPLEMENTARY INFORMATION: VMS Mobile Transceiver Units Faria WatchDog 750VMS With VTERM The Faria WatchDog... when the vessel goes to sea. The Faria WatchDog 750VMS has omni-directional Iridium, GPS, and GSM/GPRS... WatchDog Inc., P.O. Box 486, Uncasville, CT 06382, mark@fariawatchdog.net ; (860) 608-5875; (fax):...

  3. Socializing Messages in Blue-Collar Families: Communicative Pathways to Social Mobility and Reproduction

    ERIC Educational Resources Information Center

    Lucas, Kristen

    2011-01-01

    This study explicitly links processes of anticipatory socialization to social mobility and reproduction. An examination of the socializing messages exchanged between blue-collar parents (n = 41) and their children (n = 25) demonstrate that family-based messages about work and career seldom occur in straightforward, unambiguous ways. Instead,…

  4. Divergent Perspectives on Language-Discordant Mobile Medical Professionals' Communication with Colleagues: An Exploratory Study

    ERIC Educational Resources Information Center

    Gasiorek, Jessica; van de Poel, Kris

    2012-01-01

    Little is known about how language-discordant mobile medical professionals (MMPs), defined as doctors who work in foreign countries, cultures, and languages, interact with their colleagues. The number of MMPs around the world is growing, and their interactions with colleagues have direct consequences for both patients' health and their own…

  5. Local Sociality in Young People's Mobile Communications: A Korean Case Study

    ERIC Educational Resources Information Center

    Yoon, Kyongwon

    2006-01-01

    Drawing upon ethnographic data, this article explores how young Koreans appropriate mobile phones. By examining the role of local norms of sociality among young people, the study shows that this "individualizing" technology is articulated through "traditionalizing" forces. Despite dominant representations of young people's individualization via…

  6. Experiments for Ka-band mobile applications: The ACTS mobile terminal

    NASA Technical Reports Server (NTRS)

    Estabrook, Polly; Dessouky, Khaled; Jedrey, Thomas

    1990-01-01

    To explore the potential of Ka-band to support mobile satellite services, the Jet Propulsion Laboratory (JPL) has initiated the design and development of a Ka-band land-mobile terminal to be used with the Advanced Communications Technology Satellite (ACTS). The planned experimental setup with ACTS is described. Brief functional descriptions of the mobile and fixed terminals are provided. The inputs required from the propagation community to support the design activities and the planned experiments are also discussed.

  7. Connecting with Different Audiences: The Anatomy of Communication is Essential

    ERIC Educational Resources Information Center

    Evans, Darrell J. R.

    2013-01-01

    In the twenty-first century, communication has become truly global. Advances in technology have opened up a host of ways in which we are able to communicate to retrieve or pass on information and knowledge. In many cases we have moved from a place-based communication approach to one of increasing mobility. With this shift in approach, it is…

  8. Advanced Communication and Control for Distributed Energy Resource Integration: Phase 2 Scientific Report

    SciTech Connect

    BPL Global

    2008-09-30

    The objective of this research project is to demonstrate sensing, communication, information and control technologies to achieve a seamless integration of multivendor distributed energy resource (DER) units at aggregation levels that meet individual user requirements for facility operations (residential, commercial, industrial, manufacturing, etc.) and further serve as resource options for electric and natural gas utilities. The fully demonstrated DER aggregation system with embodiment of communication and control technologies will lead to real-time, interactive, customer-managed service networks to achieve greater customer value. Work on this Advanced Communication and Control Project (ACCP) consists of a two-phase approach for an integrated demonstration of communication and control technologies to achieve a seamless integration of DER units to reach progressive levels of aggregated power output. Phase I involved design and proof-of-design, and Phase II involves real-world demonstration of the Phase I design architecture. The scope of work for Phase II of this ACCP involves demonstrating the Phase I design architecture in large scale real-world settings while integrating with the operations of one or more electricity supplier feeder lines. The communication and control architectures for integrated demonstration shall encompass combinations of software and hardware components, including: sensors, data acquisition and communication systems, remote monitoring systems, metering (interval revenue, real-time), local and wide area networks, Web-based systems, smart controls, energy management/information systems with control and automation of building energy loads, and demand-response management with integration of real-time market pricing. For Phase II, BPL Global shall demonstrate the Phase I design for integrating and controlling the operation of more than 10 DER units, dispersed at various locations in one or more Independent System Operator (ISO) Control Areas, at

  9. Communication: Slow relaxation, spatial mobility gradients, and vitrification in confined films

    SciTech Connect

    Mirigian, Stephen; Schweizer, Kenneth S.

    2014-10-28

    Two decades of experimental research indicate that spatial confinement of glass-forming molecular and polymeric liquids results in major changes of their slow dynamics beginning at large confinement distances. A fundamental understanding remains elusive given the generic complexity of activated relaxation in supercooled liquids and the major complications of geometric confinement, interfacial effects, and spatial inhomogeneity. We construct a predictive, quantitative, force-level theory of relaxation in free-standing films for the central question of the nature of the spatial mobility gradient. The key new idea is that vapor interfaces speed up barrier hopping in two distinct, but coupled, ways by reducing near surface local caging constraints and spatially long range collective elastic distortion. Effective vitrification temperatures, dynamic length scales, and mobile layer thicknesses naturally follow. Our results provide a unified basis for central observations of dynamic and pseudo-thermodynamic measurements.

  10. System considerations, projected requirements and applications for aeronautical mobile satellite communications for air traffic services

    NASA Technical Reports Server (NTRS)

    Mcdonald, K. D.; Miller, C. M.; Scales, W. C.; Dement, D. K.

    1990-01-01

    The projected application and requirements in the near term (to 1995) and far term (to 2010) for aeronautical mobile services supporting air traffic control operations are addressed. The implications of these requirements on spectrum needs, and the resulting effects on the satellite design and operation are discussed. The U.S. is working with international standards and regulatory organizations to develop the necessary aviation standards, signalling protocols, and implementation methods. In the provision of aeronautical safety services, a number of critical issues were identified, including system reliability and availability, access time, channel restoration time, interoperability, pre-emption techniques, and the system network interfaces. Means for accomplishing these critical services in the aeronautical mobile satellite service (AMSS), and the various activities relating to the future provision of aeronautical safety services are addressed.

  11. Communication: Slow relaxation, spatial mobility gradients, and vitrification in confined films

    NASA Astrophysics Data System (ADS)

    Mirigian, Stephen; Schweizer, Kenneth S.

    2014-10-01

    Two decades of experimental research indicate that spatial confinement of glass-forming molecular and polymeric liquids results in major changes of their slow dynamics beginning at large confinement distances. A fundamental understanding remains elusive given the generic complexity of activated relaxation in supercooled liquids and the major complications of geometric confinement, interfacial effects, and spatial inhomogeneity. We construct a predictive, quantitative, force-level theory of relaxation in free-standing films for the central question of the nature of the spatial mobility gradient. The key new idea is that vapor interfaces speed up barrier hopping in two distinct, but coupled, ways by reducing near surface local caging constraints and spatially long range collective elastic distortion. Effective vitrification temperatures, dynamic length scales, and mobile layer thicknesses naturally follow. Our results provide a unified basis for central observations of dynamic and pseudo-thermodynamic measurements.

  12. Multi-purpose HealthCare Telemedicine Systems with mobile communication link support

    PubMed Central

    Kyriacou, E; Pavlopoulos, S; Berler, A; Neophytou, M; Bourka, A; Georgoulas, A; Anagnostaki, A; Karayiannis, D; Schizas, C; Pattichis, C; Andreou, A; Koutsouris, D

    2003-01-01

    The provision of effective emergency telemedicine and home monitoring solutions are the major fields of interest discussed in this study. Ambulances, Rural Health Centers (RHC) or other remote health location such as Ships navigating in wide seas are common examples of possible emergency sites, while critical care telemetry and telemedicine home follow-ups are important issues of telemonitoring. In order to support the above different growing application fields we created a combined real-time and store and forward facility that consists of a base unit and a telemedicine (mobile) unit. This integrated system: can be used when handling emergency cases in ambulances, RHC or ships by using a mobile telemedicine unit at the emergency site and a base unit at the hospital-expert's site, enhances intensive health care provision by giving a mobile base unit to the ICU doctor while the telemedicine unit remains at the ICU patient site and enables home telemonitoring, by installing the telemedicine unit at the patient's home while the base unit remains at the physician's office or hospital. The system allows the transmission of vital biosignals (3–12 lead ECG, SPO2, NIBP, IBP, Temp) and still images of the patient. The transmission is performed through GSM mobile telecommunication network, through satellite links (where GSM is not available) or through Plain Old Telephony Systems (POTS) where available. Using this device a specialist doctor can telematically "move" to the patient's site and instruct unspecialized personnel when handling an emergency or telemonitoring case. Due to the need of storing and archiving of all data interchanged during the telemedicine sessions, we have equipped the consultation site with a multimedia database able to store and manage the data collected by the system. The performance of the system has been technically tested over several telecommunication means; in addition the system has been clinically validated in three different countries using

  13. Communications

    NASA Technical Reports Server (NTRS)

    Stouffer, Donald D.

    1990-01-01

    Communication in its many forms is a critical component for an effective Space Grant Program. Good communication is needed within individual Space Grant College/Consortia, for example between consortium affiliates and the consortium program office. Effective communication between the several programs, NASA Headquarters, and NASA field centers also is required. Further, communication among the above program elements, industry, local and state government, and the public also are necessary for meeting program objectives.

  14. The Integrated Safety-Critical Advanced Avionics Communication and Control (ISAACC) System Concept: Infrastructure for ISHM

    NASA Technical Reports Server (NTRS)

    Gwaltney, David A.; Briscoe, Jeri M.

    2005-01-01

    Integrated System Health Management (ISHM) architectures for spacecraft will include hard real-time, critical subsystems and soft real-time monitoring subsystems. Interaction between these subsystems will be necessary and an architecture supporting multiple criticality levels will be required. Demonstration hardware for the Integrated Safety-Critical Advanced Avionics Communication & Control (ISAACC) system has been developed at NASA Marshall Space Flight Center. It is a modular system using a commercially available time-triggered protocol, ?Tp/C, that supports hard real-time distributed control systems independent of the data transmission medium. The protocol is implemented in hardware and provides guaranteed low-latency messaging with inherent fault-tolerance and fault-containment. Interoperability between modules and systems of modules using the TTP/C is guaranteed through definition of messages and the precise message schedule implemented by the master-less Time Division Multiple Access (TDMA) communications protocol. "Plug-and-play" capability for sensors and actuators provides automatically configurable modules supporting sensor recalibration and control algorithm re-tuning without software modification. Modular components of controlled physical system(s) critical to control algorithm tuning, such as pumps or valve components in an engine, can be replaced or upgraded as "plug and play" components without modification to the ISAACC module hardware or software. ISAACC modules can communicate with other vehicle subsystems through time-triggered protocols or other communications protocols implemented over Ethernet, MIL-STD- 1553 and RS-485/422. Other communication bus physical layers and protocols can be included as required. In this way, the ISAACC modules can be part of a system-of-systems in a vehicle with multi-tier subsystems of varying criticality. The goal of the ISAACC architecture development is control and monitoring of safety critical systems of a

  15. PERFORMANCE CRITERIA, A SYSTEM OF COMMUNICATION FOR MOBILIZING BUILDING INDUSTRY RESOURCES.

    ERIC Educational Resources Information Center

    JACQUES, RICHARD G.

    A PROGRAM TO TEST AND DEMONSTRATE THE EFFICACY OF PERFORMANCE CRITERIA FOR UNIVERSITY BUILDING DESIGN AND CONSTRUCTION IS UNDER WAY IN NEW YORK STATE UNDER THE AUSPICES OF THE NEW YORK STATE UNIVERSITY CONSTRUCTION FUND. THE PROGRAM IS TO RESULT IN AN EXTENSIVE LIBRARY OF PERFORMANCE CRITERIA TO AID COMMUNICATION WITH ALL SECTORS OF THE BUILDING…

  16. Small-Scale Design Experiments as Working Space for Larger Mobile Communication Challenges

    ERIC Educational Resources Information Center

    Lowe, Sarah; Stuedahl, Dagny

    2014-01-01

    In this paper, a design experiment using Instagram as a cultural probe is submitted as a method for analyzing the challenges that arise when considering the implementation of social media within a distributed communication space. It outlines how small, iterative investigations can reveal deeper research questions relevant to the education of…

  17. An experiment in remote manufacturing using the advanced communications technology satellite

    NASA Technical Reports Server (NTRS)

    Tsatsoulis, Costas; Frost, Victor

    1991-01-01

    The goal of the completed project was to develop an experiment in remote manufacturing that would use the capabilities of the ACTS satellite. A set of possible experiments that could be performed using the Advanced Communications Technology Satellite (ACTS), and which would perform remote manufacturing using a laser cutter and an integrated circuit testing machine are described in detail. The proposed design is shown to be a feasible solution to the offered problem and it takes into consideration the constraints that were placed on the experiment. In addition, we have developed two more experiments that are included in this report: backup of rural telecommunication networks, and remote use of Synthetic Aperture Radar (SAR) data analysis for on-site collection of glacier scattering data in the Antarctic.

  18. Design and Development of a Baseband Processor for the Advanced Communications Technology Satellite

    NASA Technical Reports Server (NTRS)

    Lee, Kerry D.

    1996-01-01

    This paper describes the implementation of the operational baseband processor (BBP) subsystem on board the NASA Advanced Communications Technology Satellite (ACTS). The BBP supports the network consisting of the NASA ground station (NGS) low burst rate (LBR) terminals, and the T1 very small aperture terminals (VSAT's), to provide flexible, demand assigned satellite switched (SS), baseband processed frequency division modulated (FDM)/time division multiple access (TDMA) operations. This paper presents an overview of the baseband processor and includes a description of the data flow, functional block diagrams, and a discussion of the implementation of BBP. A discussion of the supporting technologies for the BBP is presented. A brief summary of BBP-level performance testing is also presented. Finally, a discussion of the implications of current technology on the BBP design, if it were to be developed today, is presented.

  19. Teleoperation of an experimental mobile vehicle via a free-space optical laser line-of-sight communication link for use in nuclear power plant environments

    NASA Astrophysics Data System (ADS)

    Girach, Khalid; Bouazza-Marouf, K.; Kerr, David; Hewit, Jim

    1994-11-01

    The paper describes the investigations carried out to implement a line of sight control and communication link for a mobile robot vehicle for use in structured nuclear semi-hazardous environments. Line of sight free space optical laser communication links for remote teleoperation have important applications in hazardous environments. They have certain advantages over radio/microwave links and umbilical control such as greater protection against generation of and susceptance to electro-magnetic fields. The cable-less environment provides increased integrity and mechanical freedom to the mobile robot. However, to maintain the communication link, continuous point and tracking is required between the base station and the mobile vehicle. This paper presents a novel two ended optical tracking system utilizing the communication laser beams and photodetectors. The mobile robot is a six wheel drive vehicle with a manipulator arm which can operate in a variety of terrain. The operator obtains visual feedback information from cameras placed on the vehicle. From this information, the speed and direction of the vehicle can be controlled from a joystick panel. We describe the investigations carried out for the communication of analogue video and digital data signals over the laser link for speed and direction control.

  20. Globalization and advances in information and communication technologies: the impact on nursing and health.

    PubMed

    Abbott, Patricia A; Coenen, Amy

    2008-01-01

    Globalization and information and communication technology (ICT) continue to change us and the world we live in. Nursing stands at an opportunity intersection where challenging global health issues, an international workforce shortage, and massive growth of ICT combine to create a very unique space for nursing leadership and nursing intervention. Learning from prior successes in the field can assist nurse leaders in planning and advancing strategies for global health using ICT. Attention to lessons learned will assist in combating the technological apartheid that is already present in many areas of the globe and will highlight opportunities for innovative applications in health. ICT has opened new channels of communication, creating the beginnings of a global information society that will facilitate access to isolated areas where health needs are extreme and where nursing can contribute significantly to the achievement of "Health for All." The purpose of this article is to discuss the relationships between globalization, health, and ICT, and to illuminate opportunities for nursing in this flattening and increasingly interconnected world. PMID:18922277