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1

Research on Switching Behavior of Mobile Communication Services  

Microsoft Academic Search

In the mobile communications market, the homogeneity phenomenon of product's service appears. The paper combines the Technology Acceptance Model (TAM) and Switching Cost Theory to construct the Convert Selection Model about the mobile communication services for users, which mainly analyzed from five dimensions: perceived switching costs, differences in perceived usefulness, differences in perceived ease of use, perceived difference between the

Qianfan Zhang; Shuiping Mao; Zhangshu Jia

2010-01-01

2

Autonomous mobile communication relays  

NASA Astrophysics Data System (ADS)

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.

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

2002-07-01

3

Advanced Communications Technology: Mobile Communications Requirements Report  

NASA Astrophysics Data System (ADS)

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.

1998-05-01

4

Application of Mobile Router to Military Communications.  

National Technical Information Service (NTIS)

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-r...

D. H. Stewart W. D. Ivancic T. L. Bell B. A. Kachmar D. Shell K. Leung

2002-01-01

5

Mobile telecommunication: Current knowledge on risk perception and risk communication: Results gained within the German Mobile Telecommunication Research Programme  

Microsoft Academic Search

Factors influencing the public' risk perception have already been investigated since the 70s of the last century. With the increased use of mobile telecommunication and the increased public attention to potential health risks from electromagnetic fields, the risk perception and society's dealing with the topic “mobile telecommunication” came into focus. From 2002 to 2008, the German Mobile Telecommunication Research Programme

Poelzl Christiane

2011-01-01

6

Advanced Communications Technology: Mobile Communications Requirements Report.  

National Technical Information Service (NTIS)

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 operatio...

1998-01-01

7

Fade-Free Mobile Communication  

NASA Technical Reports Server (NTRS)

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.

Stevenson, C. R.

1986-01-01

8

Mobile IP LAN for ARL Mobile Communications/Networking Testbed.  

National Technical Information Service (NTIS)

This report describes the protocol and implementation of a Mobile IP (Internet protocol) LAN (local area network) for the LAN of the U.S. Army Research Laboratory (ARL) Mobile Communications/Networking Testbed. Mobile IP LAN protocol is developed to allow...

B. B. Luu

2001-01-01

9

Research on the cancellation of Doppler Offset by information aid for aviation Mobile Broadband Communication  

Microsoft Academic Search

A new method, IAADO (Information-Aided Anti-Doppler-Offset), aiming at eliminating ICI (Inter-Channel-Interference) caused by DFO (Doppler Frequency Offset) and improving the performance of AMBC (Aviation Mobile Broadband Communication), is presented with a view to the characteristics of the high DFO of aviation channel and the aircraft as a platform of AMBC. The strong ICI caused by large DFO, degrades the performance

Wu Xian; Zhang Jun; Liu Zhongkan

2008-01-01

10

Mobile and wireless communications networks  

Microsoft Academic Search

The purpose of this tutorial is to highlight several aspects of mobile and wireless communications networks. A first part presents a brief overview of the market and technology evolution. The second part is devoted to the radio propagation channel characteristics. In the third section, we present an overview of the transmission techniques related to the definition of new mobile communications

Ghais El Zein

2004-01-01

11

Reliable Communication for Highly Mobile Agents  

Microsoft Academic Search

The provision of a reliable communication infrastructure for mobile agents is still an open research issue. The challenge to reliability we address in this work does not come from the possibility of faults, but rather from the mere presence of mobility, which complicates the problem of ensuring the delivery of information even in a fault-free network. For instance, the asynchronous

Amy L. Murphy; Gian Pietro Picco

1999-01-01

12

Mobile Communication Via Satellite  

NASA Technical Reports Server (NTRS)

System mixes real-time and delayed-transmission channels. Combination of L-band and SHF links connect fixed and mobile equipment on ground to satellite relay. Software and hardware architecture conforms structure of open-system-interconnection model suggested by International Standards Organization.

Yan, Tsun-Yee; Naderi, Firouz M.

1988-01-01

13

Supporting Secure Communication and Data Collection in Mobile Sensor Networks  

Microsoft Academic Search

Abstract, Sensor deployments may be static, but researchers have recently been making a case for mobile collector nodes to enhance data acquisition. Since mobile nodes are often more privileged, their compromise can give the adversary a significant advantage. Hence, security mechanisms for such networks must tolerate mobile node compromises. Unlike static sensors, which communicate mostly with their neighbors, mobile nodes

Li Zhou; Jinfeng Ni; Chinya V. Ravishankar

2006-01-01

14

Trends in mobile satellite communication  

NASA Technical Reports Server (NTRS)

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.

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

1993-01-01

15

Application of Mobile Router to Military Communications  

NASA Technical Reports Server (NTRS)

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.

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

2002-01-01

16

Communications Systems for Mobile Robotics  

SciTech Connect

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).

Futterman, J A; Pao, H

2003-12-08

17

Antennas for mobile satellite communications  

NASA Astrophysics Data System (ADS)

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.

Huang, John

1991-12-01

18

Satellite communication and navigation for mobile users  

NASA Technical Reports Server (NTRS)

Efforts made to utilize space technology for solving communication and navigation problems faced by mobile users in earth orientated situations are outlined. Applications include transoceanic airline communications, reliable long range ship-shore communications, emergency communications in regions with rough terrain, and military operations.

Bernstein, S. L.

1972-01-01

19

Effectively Communicating Qualitative Research  

ERIC Educational Resources Information Center

This article is a guide for counseling researchers wishing to communicate the methods and results of their qualitative research to varied audiences. The authors posit that the first step in effectively communicating qualitative research is the development of strong qualitative research skills. To this end, the authors review a process model for…

Ponterotto, Joseph G.; Grieger, Ingrid

2007-01-01

20

Spread spectrum mobile radio communications  

NASA Astrophysics Data System (ADS)

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.

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

1987-02-01

21

Mobile communication security controllers an evaluation paper  

Microsoft Academic Search

Cellular communication via a traditional mobile handset is a ubiquitous part of modern life and as device technology and network performance continues to advance, it becomes possible for laptop computers, Personal Digital Assistants [PDAs; Note abbreviations will be shown in square brackets to avoid confusion with references.] and even electrical meters to better exploit mobile networks for wireless communication. As

Keith E. Mayes; Konstantinos Markantonakis

2008-01-01

22

Effective Protocols for Mobile Communications and Networking  

SciTech Connect

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.

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

1998-12-01

23

"Mass" in Communication Research.  

ERIC Educational Resources Information Center

Summarizes the arguments against the use of the term "mass" in communication research based on confusions which relate it to the theses of mass society theory or the notion that the term is too simple for the complex nature of communication. (JMF)

Corner, John

1979-01-01

24

Reduced-Bandwidth Coding for Mobile Communication  

NASA Technical Reports Server (NTRS)

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.

Davarian, F.

1986-01-01

25

Space communications technology research in CRL  

NASA Astrophysics Data System (ADS)

This report overviews the current research of space communications technology in Communications Research Laboratory (CRL), Ministry of Posts, and Telecommunications. The Engineering Test Satellite-5 (ETS-5) project has been conducted these five years for mobile communications development. The international cooperations using ETS-5 has been performed. It describes the project of Communications and Broadcasting Engineering Test Satellite (COMETS) to be launched in 1997 for experiments of advanced mobile satellite communication and advanced broadcasting. It also mentions the project of Engineering Test Satellite-6 (ETS-6), to be launched in 1994, in which the CRL's missions of ETS-6 are the inter-satellite communication of S-band, millimeter-wave, and optical. Finally, this report describes the technologies of large antenna assembly experiment, small satellite communications, and cluster satellite briefly.

Iida, Takashi

1993-03-01

26

USDA Forest Service mobile satellite communications applications  

NASA Technical Reports Server (NTRS)

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.

Warren, John R.

1990-01-01

27

The triple helix model in Korean mobile communication technology innovation  

Microsoft Academic Search

The aim of this research is to analyse the determining factors for the success of the Korean mobile communications industry based on the CDMA technology. We argue that the determining factors of the success lie in the close co-operative working relationship between the government, the research institutes and the industries, the unprecedented establishment of the service commercialisation and the expansion

Sang-Young Han; Yun-Bong Auh; YeongWha Sawng

2001-01-01

28

Impacts of mobile agent technology on mobile communication system evolution  

Microsoft Academic Search

The development of third-generation mobile communication systems, such as UMTS, should be based on state-of-the-art middleware technologies. Today distributed object technology (DOT), such as OMG's CORBA, has gained considerable acceptance in the telecommunications environment, within the evolution of IN, TMN systems, and also in the context of UMTS design. Another new software technology, mobile agent technology (MAT), is gaining momentum

LARS HAGEN; MARKUS BREUGST

1998-01-01

29

Mobile satellite communications in the Forest Service  

NASA Astrophysics Data System (ADS)

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.

Warren, John R.

1988-05-01

30

Mobile satellite communications in the Forest Service  

NASA Technical Reports Server (NTRS)

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.

Warren, John R.

1988-01-01

31

Personal Mobile Communications by Satellite.  

National Technical Information Service (NTIS)

The engineering feasibility of satellite systems for paging and message services to mobile users with small terminals is demonstrated. The satellite itself would provide cover mainly in rural and semi-urban areas, but the coverage could be extended into u...

R. J. Cocks P. S. Hansell R. Krawec D. Lewin

1984-01-01

32

Satellite multiple access systems for mobile communication  

NASA Technical Reports Server (NTRS)

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.

Lewis, J. L.

1979-01-01

33

GLOBAL MOBILE SATELLITE COMMUNICATIONS: A REVIEW OF THREE CONTENDERS  

Microsoft Academic Search

The era of satellite-based mobile communications systems started with the first MARISAT satellite which was launched into a geostationary orbit over the Pacific Ocean in 1976 to provide communications between ships and shore stations. The combination of high cost and unacceptably large equipment has kept mobile satellite communications (MSC) systems from appealing to the wider market of personal mobile communications.

Gary M. Comparetto

1994-01-01

34

Anonymous communications in mobile ad hoc networks  

Microsoft Academic Search

Abstract—Due to the broadcast nature of radio transmissions, communications in mobile ad hoc networks (MANETs) are more susceptible to malicious traffi ca nalysis. In this paper we propose a novel anonymous on-demand routing protocol, termed MASK, to enable anonymous,communications thereby thwarting possible traffic analysis attacks. Based on a new cryptographic concept called pairing, we first propose an anonymous neighborhood authentication

Yanchao Zhang; Wei Liu; Wenjing Lout

2005-01-01

35

Modeling and Analysis of Mobility Management in Mobile Communication Networks  

PubMed Central

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.

Yoon, Ji Hyun; Kim, Chesoong

2014-01-01

36

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

PubMed

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

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

2011-10-01

37

Mobile Computing, Programming, Games and Online Communities: Changes to the Communicative Ecology of Design Students Through Mobile Computing: Part 2  

Microsoft Academic Search

In this paper, we discuss the influence the increased mobility afforded by Tablet PCs has had on the way multimedia students learn programming concepts and practice skills and techniques through their communicative ecology. Following on from our previous ethnographic action research study, on mobile computing, visual diaries, learning and communication, (Berry & Hamilton, 2006) we allocated Tablet PCs to a

Margaret Hamilton; Marsha Berry

38

The Global System for Mobile Communications Short Message Service  

Microsoft Academic Search

This tutorial presents an overview of the Global System for Mobile Communications Short Message Service from the viewpoint of implementing new telematic services. The SMS offers the users of GSM networks the ability to exchange alphanumeric messages up to the limit of 160 characters. The tutorial is motivated by an acute absence of research publications in this field. The information

C. Peersman; S. Cvetkovic; P. Griffiths; H. Spear

2000-01-01

39

Time reversal communication with a mobile source.  

PubMed

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

Song, H C

2013-10-01

40

Analysis of maritime mobile satellite communication systems  

NASA Astrophysics Data System (ADS)

The communication channel between a satellite and a ship earth station (SES) is described by a model which includes multipath fading, Doppler shift and noise. Multipath fading is caused by reflections from the sea surface. These reflections can affect the system performance, especially at low elevation angles or when SES is using low gain antennas. Doppler shift is a very important effect when using low altitude satellites, because of the high velocities involved. A software simulator is described and a simulator is presented for multipath fading in the maritime communications environment. Analysis of throughput of an unslotted Aloha maritime mobile satellite communication channel is also presented.

Zapata, Augusto J.

1988-12-01

41

Phased array for mobile satellite communications  

NASA Astrophysics Data System (ADS)

An L-band phased array antenna concept for mobile satellite communications is presented. The array is a multilayer structure with integrated 4-bit switched stub phase shifters and aperture coupled right hand circularly polarized antenna elements. The integrated phased array has an interface for direct computer control. Diagrams describing the operation and structure of the antenna are shown.

Ziegler, Volker

1990-11-01

42

Advanced Communications Payload for Mobile Applications.  

National Technical Information Service (NTIS)

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...

S. A. Ames R. K. Kwan

1990-01-01

43

Mobile satellite communications - Vehicle antenna technology update  

NASA Astrophysics Data System (ADS)

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.

Bell, D.; Naderi, F. M.

44

Antenna technology for advanced mobile communication systems  

NASA Technical Reports Server (NTRS)

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.

Rammos, Emmanuel; Roederer, Antoine; Rogard, Roger

1988-01-01

45

Pilot-Tone System for Mobile Communications  

NASA Technical Reports Server (NTRS)

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.

Davarian, F.

1986-01-01

46

Antenna technology for advanced mobile communication systems  

NASA Astrophysics Data System (ADS)

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.

Rammos, Emmanuel; Roederer, Antoine; Rogard, Roger

1988-05-01

47

Inmarsat second generation satellites for mobile communications  

NASA Astrophysics Data System (ADS)

The second-generation satellites of Inmarsat (the International Maritime Satellite Organization) are in the final stage of integration and testing. The satellites will satisfy the needs originated by the rapid expansion of the system and will allow the introduction of new mobile communications services. The essentials of the spacecraft design and the types of services that will be provided using the new satellites are discussed, with particular consideration given to the characteristics of the communications transponder, its design and technology, the requirements and the design solutions, and the most significant communications parameters. Paralleled linearized traveling-wave amplifiers, L-band shaped global direct radiating array antennas, and surface-acoustic-wave channelization filters are being implemented in the system. Passive intermodulation product generation and multipaction are being recognized as design drivers.

Gambaruto, E.; Banks, D. K.; Krinsky, B.

48

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

NASA Technical Reports Server (NTRS)

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.

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

1993-01-01

49

Hybrid Mobile Communication Networks for Planetary Exploration  

NASA Technical Reports Server (NTRS)

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.

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

2007-01-01

50

Lens Antenna For Mobile/Satellite Communication  

NASA Technical Reports Server (NTRS)

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.

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

1988-01-01

51

Biometric Communication Research for Television.  

ERIC Educational Resources Information Center

Biometric communication research is defined as research dealing with the information impact of a film or television show, photographic picture, painting, exhibition, display, or any literary or functional texts or verbal stimuli on human beings, both as individuals and in groups (mass audiences). Biometric communication research consists of a…

Malik, M. F.

52

Geographical dispersal of mobile communication networks  

NASA Astrophysics Data System (ADS)

In this paper, we analyze statistical properties of a communication network constructed from the records of a mobile phone company. The network consists of 2.5 million customers that have placed 810 million communications (phone calls and text messages) over a period of 6 months and for whom we have geographical home localization information. It is shown that the degree distribution in this network has a power-law degree distribution k-5 and that the probability that two customers are connected by a link follows a gravity model, i.e. decreases as d-2, where d is the distance between the customers. We also consider the geographical extension of communication triangles and we show that communication triangles are not only composed of geographically adjacent nodes but that they may extend over large distances. This last property is not captured by the existing models of geographical networks and in a last section we propose a new model that reproduces the observed property. Our model, which is based on the migration and on the local adaptation of agents, is then studied analytically and the resulting predictions are confirmed by computer simulations.

Lambiotte, Renaud; Blondel, Vincent D.; de Kerchove, Cristobald; Huens, Etienne; Prieur, Christophe; Smoreda, Zbigniew; Van Dooren, Paul

2008-09-01

53

Research in speech communication.  

PubMed Central

Advances in digital speech processing are now supporting application and deployment of a variety of speech technologies for human/machine communication. In fact, new businesses are rapidly forming about these technologies. But these capabilities are of little use unless society can afford them. Happily, explosive advances in microelectronics over the past two decades have assured affordable access to this sophistication as well as to the underlying computing technology. The research challenges in speech processing remain in the traditionally identified areas of recognition, synthesis, and coding. These three areas have typically been addressed individually, often with significant isolation among the efforts. But they are all facets of the same fundamental issue--how to represent and quantify the information in the speech signal. This implies deeper understanding of the physics of speech production, the constraints that the conventions of language impose, and the mechanism for information processing in the auditory system. In ongoing research, therefore, we seek more accurate models of speech generation, better computational formulations of language, and realistic perceptual guides for speech processing--along with ways to coalesce the fundamental issues of recognition, synthesis, and coding. Successful solution will yield the long-sought dictation machine, high-quality synthesis from text, and the ultimate in low bit-rate transmission of speech. It will also open the door to language-translating telephony, where the synthetic foreign translation can be in the voice of the originating talker. Images Fig. 1 Fig. 2 Fig. 5 Fig. 8 Fig. 11 Fig. 12 Fig. 13

Flanagan, J

1995-01-01

54

Research in speech communication.  

PubMed

Advances in digital speech processing are now supporting application and deployment of a variety of speech technologies for human/machine communication. In fact, new businesses are rapidly forming about these technologies. But these capabilities are of little use unless society can afford them. Happily, explosive advances in microelectronics over the past two decades have assured affordable access to this sophistication as well as to the underlying computing technology. The research challenges in speech processing remain in the traditionally identified areas of recognition, synthesis, and coding. These three areas have typically been addressed individually, often with significant isolation among the efforts. But they are all facets of the same fundamental issue--how to represent and quantify the information in the speech signal. This implies deeper understanding of the physics of speech production, the constraints that the conventions of language impose, and the mechanism for information processing in the auditory system. In ongoing research, therefore, we seek more accurate models of speech generation, better computational formulations of language, and realistic perceptual guides for speech processing--along with ways to coalesce the fundamental issues of recognition, synthesis, and coding. Successful solution will yield the long-sought dictation machine, high-quality synthesis from text, and the ultimate in low bit-rate transmission of speech. It will also open the door to language-translating telephony, where the synthetic foreign translation can be in the voice of the originating talker. PMID:7479806

Flanagan, J

1995-10-24

55

Route Optimization for Intra Communication of a Nested Mobile Network  

Microsoft Academic Search

Network mobility, i.e. Internet access services for a moving network as a single unit brings about new challenging issues. A nested mobile network is a hierarchical form of multiple mobile networks. Nested mobile networks sufier from a pin- ball routing problem. This problem becomes more serious in the case of a communication between any two nodes in the same nested

Sungmin Baek; Jinkyu Yoo; Hosik Cho

56

Voice communications jamming research  

NASA Astrophysics Data System (ADS)

The effect of various types of jammers, J/S power ratios and background noise levels on voice communication materials processed by a standard Air Force voice communication system was evaluated. The measurement instruments employed were the Modified Rhyme Test (MRT) and a nonstandard voice communication performance task. Good agreement is found between the two measurement instruments in ranking the relative effectiveness of the jammers evaluated. The effect of training on naive subjects' ability to listen to voice communications under conditions of noise and jamming was studied. The results of this exploratory study indicate that training improved the performance of the listeners under all conditions tested.

Moore, T. J.

1981-06-01

57

Consensus in networks of mobile communicating agents  

NASA Astrophysics Data System (ADS)

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.

Baronchelli, Andrea; Díaz-Guilera, Albert

2012-01-01

58

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

ERIC Educational Resources Information Center

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)

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

1986-01-01

59

Biometric Communication Research for Television.  

National Technical Information Service (NTIS)

Biometric communication research is defined as research dealing with the information impact of a film or television show, photographic picture, painting, exhibition, display, or any literary or functional texts or verbal stimuli on human beings, both as i...

M. F. Malik

1978-01-01

60

Aeronautical Mobile Airport Communications System (AeroMACS)  

NASA Technical Reports Server (NTRS)

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.

Budinger, James M.; Hall, Edward

2011-01-01

61

Mobile health for non-communicable diseases in Sub-Saharan Africa: a systematic review of the literature and strategic framework for research  

PubMed Central

Background Mobile health (mHealth) approaches for non-communicable disease (NCD) care seem particularly applicable to sub-Saharan Africa given the penetration of mobile phones in the region. The evidence to support its implementation has not been critically reviewed. Methods We systematically searched PubMed, Embase, Web of Science, Cochrane Central Register of Clinical Trials, a number of other databases, and grey literature for studies reported between 1992 and 2012 published in English or with an English abstract available. We extracted data using a standard form in accordance with Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. Results Our search yielded 475 citations of which eleven were reviewed in full after applying exclusion criteria. Five of those studies met the inclusion criteria of using a mobile phone for non-communicable disease care in sub-Saharan Africa. Most studies lacked comparator arms, clinical endpoints, or were of short duration. mHealth for NCDs in sub-Saharan Africa appears feasible for follow-up and retention of patients, can support peer support networks, and uses a variety of mHealth modalities. Whether mHealth is associated with any adverse effect has not been systematically studied. Only a small number of mHealth strategies for NCDs have been studied in sub-Saharan Africa. Conclusions There is insufficient evidence to support the effectiveness of mHealth for NCD care in sub-Saharan Africa. We present a framework for cataloging evidence on mHealth strategies that incorporates health system challenges and stages of NCD care. This framework can guide approaches to fill evidence gaps in this area. Systematic review registration: PROSPERO CRD42014007527.

2014-01-01

62

SAW based systems for mobile communications satellites  

NASA Technical Reports Server (NTRS)

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.

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

1993-01-01

63

Optical Fiber Feeder for Microcellular Mobile Communication Systems (H-015)  

Microsoft Academic Search

The authors investigate the feasibility of using an optical fiber feeder for microcellular mobile communication systems. The optical feeder enables compact and low-cost base stations, easy radio channel control, and flexible mobile communication systems. Basic transmission characteristics were investigated through optical transmission experiments. Using these results, it is estimated that the optical feeder can transmit 880 telephone channels for digital

Makoto Shibutani; Toshihito Kanai; Watani Domom; Katsumi Emura; Junji Namiki

1993-01-01

64

Key Issues in Expansion of Mobile Data Communications in China  

Microsoft Academic Search

China's mobile communications market presents unique market challenges. Market is experiencing a high subscriber growth rate and its implications for business and end-users and investigation into the current status of this market will improve our understanding on how adoption of mobile communications is evolving at the end-user level. In this paper we use a descriptive method to analyze key issues

Sunanda Sangwan; Chong Guan; Louis-Francois Pau

2008-01-01

65

Interference Analysis for an Aeronautical Mobile Airport Communications System  

NASA Technical Reports Server (NTRS)

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

Wilson, Jeffrey D.; Kercewski, Robert J.

2010-01-01

66

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

ERIC Educational Resources Information Center

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

Simonic, Tomaz; Mlinar, Tomi

2000-01-01

67

Supporting the WWW in Wireless Communications Through Mobile Agents  

Microsoft Academic Search

Mobile computing is considered of major importance to the computing industry for the forthcoming years due to the progress in wireless mobile communications. We present a proxy-based architecture that manages to accelerate Web browsing in wireless Customer Premises Networks (CPN). We discuss how such an architecture is implemented using the IBM Aglets framework for mobile agents. The suggested architecture relies

Stathes Hadjiefthymiades; Vicky Matthaiou; Lazaros F. Merakos

2002-01-01

68

A generalized transmultiplexer and its application to mobile satellite communications  

NASA Technical Reports Server (NTRS)

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.

Ichiyoshi, Osamu

1990-01-01

69

Design of a Communications Network to Support Mobile Health Systems (Telemedicine) in Arkansas.  

National Technical Information Service (NTIS)

This research study analyzed the design of a communications network to support a mobile health system. The need was defined in a previous study where the concept of the integration of a mobile health care system to deliver primary medical care to the rura...

E. W. Fant J. C. Winburn

1995-01-01

70

Experimental mobile satellite system for communications using engineering test satellite-V(ETS-V/EMSS-C)  

NASA Astrophysics Data System (ADS)

For establishing key technology of the maritime satellite communication system for small vessels and the aeronautical satellite communications and for research on general mobile satellite communications, Experimental Mobile Satellite System for Communications using Engineering Test Satellite-V(ETS-V/EMSS-C) is developed in Japan. Phase C development of the satellite and transponders will start this year and development of an aircraft earth station and a coast/aeronautical earth station have started. Ship earth stations and small mobile stations will be developed in 1985. C-band and L-band frequencies are used for communications experiments. A multibeam antenna and solid state transponders are used on the satellite and digital communication technics play an important role. The satellite will be launched in 1987.

Miura, S.; Ishide, A.; Kondo, K.

1984-10-01

71

Mobile communications satellite antenna flight experiment definition  

NASA Astrophysics Data System (ADS)

There are classes of application that collectively require a variety of different types of large-aperture space antennas. Fortunately, there are a number of different deployable antenna concepts that have tremendous potential for such applications. However, these concepts vary in maturity from flight-proven designs to extremely innovative configuration definitions. But these promising concepts lack sufficient demonstrations of maturity to be seriously considered in the large size range for immediate application. The reason for this situation is an extremely limited space flight data base in addition to the technical limitations and great costs associated with meaningful ground testing of large, flexible, precision space structures. The user community of such structures, especially the commercial organizations interested in providing a Mobile Communications Satellite (MSAT) on a profit-making basis, will require significant demonstrations of technology readiness prior to application commitment. Such demonstrations will probably be based on a combination of extensive ground testing and subsequent space flight experiments. The Communications Division of the National Aeronautics and Space Administration (NASA) Office of Space Science and Applications sponsored a study at the Jet Propulsion Laboratory (JPL) to determine the technical feasibility and cost of a Shuttle-based flight experiment specifically intended for the MSAT commercial user community. The experiment will include demonstrations of technology in the areas of radio frequency (RF), sensing and control, and structures. This paper summarizes the results of the structural subsystem study. These results include experiment objective and technical approach, experiment structural description, structure/environment interactions, structural characterization, thermal characterization, structural measurement system, and experiment functional description.

Freeland, Robert E.

72

Communication Concepts for Mobile Agent Systems  

Microsoft Academic Search

Driven by the question how to identify potential communication partners and the need for well-suited communication schemes in agent-based systems, we discuss two communication concepts: sessions and global event management.

Joachim Baumann; Fritz Hohl; Nikolaos Radouniklis; Kurt Rothermel; Markus Straßer

1997-01-01

73

Efficient spectrum utilization in mobile radio communication systems  

NASA Astrophysics Data System (ADS)

The problem of efficient spectrum utilization in mobile radio communication systems is addressed. A frequency channel assignment algorithm is proposed and studied by computer simulations for applications to mobile telephone systems and combined mobile telephone and dispatch systems. Spectrum efficient modulation techniques, namely, Duobinary Coded MSK and TFM are studied for the application of data transmission via mobile radio. The performance of coherent and noncoherent detections is studied under the mobile radio environments. The probability of error is calculated for both discriminator detection and differential detection. The steady state phase error probability of a digital phase locked loop with a phase step input is calculated under the fast fading mobile radio environments.

Elnoubi, S. M.

1980-03-01

74

Voice communication research evaluation system  

NASA Astrophysics Data System (ADS)

Aircraft voice communications may be degraded by a variety of sources such as electrical and/or acoustical noise, radio interference, jamming and various other forms of distraction. The Voice Communication Research and Evaluation System, located in the Biodynamics and Bioengineering Division of the Aerospace Medical Research Laboratory, has been developed for the comprehensive analysis and enhancement of operational voice communication. The basic system is comprised of a multi-station voice communication network consisting of the USAF standard aircraft intercommunication system, a standard A-19 diluter-demand oxygen regulation system and an on line computer data collection and data analysis system that displays results in real time. The system is housed in a large reverberation chamber containing a programmable sound source capable of reproducing the spectrum and level of any AF operational noise environment. Standardized voice communication effectiveness test materials are used to assess the performance of any aspect of the total voice communication link, however, emphasis is usually placed upon the performance of the aircrew members. This paper will descibe the salient features of this unique system and provide examples of its application to voice communication problems.

McKinley, R. L.

1980-05-01

75

Mobility Environmental Research Study Mobility Testing Procedures.  

National Technical Information Service (NTIS)

Test procedures to be used for the evaluation of off-road vehicle mobility performance are presented. The development of a quantitative evaluation system represents an important step in the design of proper off-road vehicle tests. The procedures are prese...

R. A. Liston T. Czako P. Haley W. L. Harrison B. Hanamoto

1966-01-01

76

A Review of Mobile HCI Research Methods  

Microsoft Academic Search

This paper examines and reviews research methods applied within the field of mobile human-computer interaction. The purpose is to provide a snapshot of current practice for studying mobile HCI to identify shortcomings in the way research is conducted and to propose opportunities for future ap- proaches. 102 publications on mobile human-computer interaction research were categorized in a matrix relating their

Jesper Kjeldskov; Connor Graham

2003-01-01

77

Mobile communications via satellite in the 1990s  

NASA Astrophysics Data System (ADS)

The International Maritime Satellite Organization (Inmarsat) began operations in February 1982. It has the objective to provide satellite communications capacity which can best serve the mobile user in the international environment. It is pointed out that Inmarsat is the world's only organization providing commercial mobile communications via satellite. Inmarsat is concerned with the improvement of maritime communications. Attention is given to structure and financing, the Inmarsat satellites in geostationary orbit, the coast earth stations, the ship earth stations, applications and users, a future global maritime distress and safety system, polar-orbiting satellites, aeronautical communications, and the second-generation system.

Lundberg, O.

1984-07-01

78

A modified two-ring reference model for MIMO Mobile-to-Mobile communication channels  

Microsoft Academic Search

Analysis and design of multi-element antenna systems in mobile fading channels require a model for the space-time cross-correlation among the links of the underlying multiple-input multiple-output (MIMO) mobile-to-mobile (M-to-M) communication channel. In this paper, we propose a MIMO channel reference model for M-to-M communication systems that we call it as the modified geometrical two-ring model. This model is based on

Gholamreza Bakhshi; Reza Saadat; Kamal Shahtalebi

2008-01-01

79

Megatrends in Speech Communication: Theory and Research.  

ERIC Educational Resources Information Center

Identifies shifts in the speech communication field that include bridging the diversity in communication theory and research, increasing attention to policy implications and technology factors in communication research, etc. (PD)

Littlejohn, Stephen W.

1985-01-01

80

Isolated and Coupled Superquadric Loop Antennas for Mobile Communications Applications.  

National Technical Information Service (NTIS)

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 cas...

M. A. Jensen Y. Rahmat-samii

1993-01-01

81

Mobile Router Testing with Diverse RF Communications Links  

NASA Technical Reports Server (NTRS)

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.

Brooks, David; Hoder, Doug; Wilkins, Ryan

2004-01-01

82

A survey of various propagation models for mobile communication  

Microsoft Academic Search

In order to estimate the signal parameters accurately for mobile systems, it is necessary to estimate a system's propagation characteristics through a medium. Propagation analysis provides a good initial estimate of the signal characteristics. The ability to accurately predict radio-propagation behavior for wireless personal communication systems, such as cellular mobile radio, is becoming crucial to system design. Since site measurements

Tapan K. Sarkar; Zhong Ji; Kyungiung Kim; A. Medouri; Magdalena Salazar-Palma

2003-01-01

83

Cockpit weather graphics using mobile satellite communications  

NASA Astrophysics Data System (ADS)

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.

Seth, Shashi

84

Cockpit weather graphics using mobile satellite communications  

NASA Technical Reports Server (NTRS)

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.

Seth, Shashi

1993-01-01

85

The flexibility of ATM: supporting future multimedia and mobile communications  

Microsoft Academic Search

ATM is no longer considered a vision for the more distant future, but as a technology that will be deployed worldwide within the very near future, in both the private and public sectors. ATM will progressively support fixed and mobile communications in several steps, beginning with data communications and possibly leading to general purpose ATM switches for narrow- and broadband,

H. Armbruster

1995-01-01

86

Hermeneutics, Textuality, and Communication Research.  

ERIC Educational Resources Information Center

The fundamental shifts in thinking about communication theory and research that are suggested in the hermeneutic writing made available during the last decade are reviewed in this paper. The issues reviewed include a consideration of hermeneutics as a philosophy of social science, the modern conception of textuality, and the status of interpretive…

Deetz, Stanley

87

Communicating Research to Public Audiences  

NSF Publications Database

Full Proposal Preparation Instructions: This solicitation contains information that supplements the standard Grant Proposal Guide (GPG) proposal preparation guidelines. Communicating Research to Public Audiences (NSF 03-509) replaces Supplements to Active Research Awards (NSF 97-70). More comprehensive information on NSF Award Conditions is contained in the NSF Grant Policy Manual (GPM) Chapter II, available electronically on the NSF Website at http://www.nsf.gov/cgi-bin/getpub?gpm.

88

Tracking Mobile Users in Wireless Communication Networks  

Microsoft Academic Search

Tracking strategies for mobile wireless networks are studied. We assume a cellulararchitecture where base stations that are interconnected by a wired network communicatewith mobile units via wireless links. Previous works focused on the cost of utilizing thewired links for management of directories. In this paper, the issue considered is thecost of utilizing the wireless links for the actual tracking of

Amotz Bar-noy; Ilan Kessler

1993-01-01

89

Intelligent network concepts in mobile communications  

Microsoft Academic Search

A mobile cellular network architecture that is based on intelligent network concepts is presented. Subscriber service mobility and call management attributes of the network, including location information retrieval and updating, authentication, call routing, handover, charging, and operations and maintenance, are discussed

Bijan Jabbari

1992-01-01

90

Presence Aware Location-Based Service For Managing Mobile Communications  

Microsoft Academic Search

Presence technology based on Session Initiation Protocol can be used as an enabling platform for delivering communication and providing event-based services. We present a mobile workforce management solution which integrates fleet management with presence-based communication to show how presence technology can be used to realize location-based communication services. In particular, our solution integrates a user's presence information with their vehicle's

Vishal Kumar Singh; Henning Schulzrinne; Piotr Boni; Boris Elman; David Kenneson

2007-01-01

91

Research on Mobile Payment in the E-Commerce  

Microsoft Academic Search

The progress of mobile communication technology and the development of mobile termination promoted the mobilization development of e-commerce. At the same time, mobile payment, being the core technology of mobile commerce, is widely used in handling business transactions. This thesis analyzes the development of domestic and foreign mobile payment, the existent problem. Aiming at the characters of Chinese mobile payment

Yunhong Li; Siwen Luo

2008-01-01

92

Development of a mobile satellite communication unit  

NASA Technical Reports Server (NTRS)

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.

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

1988-01-01

93

[Mobile communication and health of population: estimation of danger, social and ethical problems].  

PubMed

Population lives under new electromagnetic conditions: constant round-the-clock compulsory chronic exposure of all groups of population to modulated wide spectrum of EMF RF during the work of base stations of mobile communication; daily and lifelong (from childhood) exposure of the brain to EMF RF of the mobile phone. Effects of exposure to EMF RF of low levels are presented. Results of research into chronic EMF RF exposure are absent. International recommendations and domestic guidelines do not take into account the changing conditions of EMF RF influence on the population: the brain has become a critical body, and children have been included in the risk group. Population actively continues to use mobile communication. In this situation estimation of the risks from mobile communication has become a social and ethical problem. PMID:21866836

Grigor'ev, Iu G; Grigor'ev, O A

2011-01-01

94

Development of a mobile satellite communication unit  

Microsoft Academic Search

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

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

1988-01-01

95

Research on Route Optimization in Mobile Networks  

Microsoft Academic Search

Mobile network (NEMO) is an extension of MIPv6. And route optimization for nested mobile networks is one of the major challenges in NEMO research. Some current solutions have too much additional cost and can't deal with fast handoff scenario well. Aiming at these problems, we give a new route optimization algorithm for nested mobile network in this paper. The basic

Wei Su; Hongke Zhang; Yan Ren

2006-01-01

96

Interference Analysis for an Aeronautical Mobile Airport Communications System.  

National Technical Information Service (NTIS)

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 Euro...

J. D. Wilson R. J. Kerczewski

2011-01-01

97

Analysis of Maritime Mobile Satellite Communication Systems.  

National Technical Information Service (NTIS)

The communication channel between a satellite and a ship earth station (SES) is described by a model which includes multipath fading, doppler shift and noise. Multipath fading is caused by reflections from the sea surface. These reflections can affect the...

A. J. Zapata

1988-01-01

98

Satellite systems requirements for land mobile communications  

NASA Technical Reports Server (NTRS)

The system design objective is to provide a satellite link through a gateway station, connecting mobile users in areas not served by a terrestrial cellular system to the switched telephone network (STN). The proposed frequency allocation comprises a pair of 10-MHz bands in the 806-890 MHz range specified by the 1979 World Administrative Radio Conference (WARC) for land-mobile satellite service (LMSS). The satellite design is constrained by projected STS capability with an upper stage of the wide-body Centaur or Integral Propulsion System (IPS) type. For the latter (a TRW design), the payload is limited to approximately 10,400 lb. The design is to be based on 1990's technology, with initial operating capability scheduled for 1995. The satellite should be designed for a 7-year life. Mobile-unit compatibility with cellular system specifications is desirable, if consistent with other system requirements.

Horstein, M.

1983-01-01

99

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

NASA Technical Reports Server (NTRS)

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.

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

1991-01-01

100

The Turbo Principle in Mobile Communications  

Microsoft Academic Search

This overview talk shows that the so-called turbo codes(decoders) entail a much broader principle. It dis- cusses how the feedback of extrinsic information which we call the turbo principle can be used in many mobile com- munications receivers to improve performance through iter- ative processing. As an analysis and design tool the EXIT charts of mutual information transfer are used.

Joachim Hagenauer

101

Mobile Communication and Innovation: More than Convenience  

Microsoft Academic Search

Systems of mobile tools and practices support innovation through access to people and information, the reduction of barriers to the innovation process, and increased engagement. These positive effects can be understood by overlaying the needs for motivation, opportunity, and ability in all forms of performance. We offer illustrations of these relationships, a resulting pair of design recommendations, and ultimately, an

Terri L. Griffith; Lynne P. Cooper; T. Milbrourn

2010-01-01

102

Wireless\\/mobile communication Aegis taciturn  

Microsoft Academic Search

“Technology does not drive change, it enables change.” The primary purpose of Technology is its implementation in day-to-day life wherein it could enhance the lifestyle as well as provide better safety and performance to its end users. The government has enforced stringent laws against usage of mobile phones while driving a vehicle. Yet, there seems to be a sense of

S. Aparajith; M. L. Naarayan

2010-01-01

103

Mobile satellite communications - Applications for developing countries  

NASA Astrophysics Data System (ADS)

The paper considers the institutional commitments and development of new service applications of the International Maritime Satellite Organization. It illustrates how a mobile-satellite system can offer a range of applications and reach user communities that cannot be served by fixed systems.

von Noorden, Wolf D.

104

Mobile message services and communications policy  

Microsoft Academic Search

Something of a design after-thought, mobile phone SMS (Short-Message Services) have been enthusiastically adopted by consumers worldwide, who have created a new text culture. SMS is now being deployed to provide a range of services and transactions, as well as playing a critical role in offering an interactive path for television broadcasting. In this paper we offer a case study

Gerard Goggin; Christina Spurgeon

2005-01-01

105

Land-mobile satellite communication system  

NASA Technical Reports Server (NTRS)

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.

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

1993-01-01

106

High Spectral Efficient and Flexible Next Generation Mobile Communications  

Microsoft Academic Search

In this paper we identify and describe the requirements and challenges of next generation mobile communications systems. The so-called fourth genera- tion (4G) aims at throughput rates of more than 100 MBit=s outdoors with high mobility and 1 GBit=s indoors. This requires new advanced techniques in the air interface of such a system. We outline new possible techniques and introduce

Simon Plass; Stephan Sand; Mikael Sternad; Arne Svensson

2007-01-01

107

High Spectral Efficient and Flexible Next Generation Mobile Communications  

Microsoft Academic Search

In this article we identify and describe the requirements and challenges of next generation mobile communications systems.\\u000a The so-called fourth generation (4G) aims at throughput rates of more than 100 MBit\\/s outdoors with high mobility and 1GBit\\/s\\u000a indoors. This requires new advanced techniques in the air interface of such a system. We outline new possible techniques and\\u000a introduce a future

Simon Plass; Stephan Sand; Mikael Sternad; Arne Svensson

2008-01-01

108

Mobility of a Disaster Recover Communication System  

Microsoft Academic Search

What is the best platform to build a Disaster Management Communication System (DMCS)? There is a need to investigate how to best use a DMCS. The two most important uses of a DMCS for any size disaster, is the need for information and getting relief to those that need it. The DMCS needs to collect information from the people affected

Edward Sobanski; Barbara Nicolai

2011-01-01

109

Mobile satellite service communications tests using a NASA satellite  

NASA Technical Reports Server (NTRS)

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.

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

1995-01-01

110

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

PubMed

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

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

2013-01-01

111

Research Supporting Satellite Communications Technology  

NASA Technical Reports Server (NTRS)

This report describes the second year of research effort under the grant Research Supporting Satellite Communications Technology. The research program consists of two major projects: Fault Tolerant Link Establishment and the design of an Auto-Configurable Receiver. The Fault Tolerant Link Establishment protocol is being developed to assist the designers of satellite clusters to manage the inter-satellite communications. During this second year, the basic protocol design was validated with an extensive testing program. After this testing was completed, a channel error model was added to the protocol to permit the effects of channel errors to be measured. This error generation was used to test the effects of channel errors on Heartbeat and Token message passing. The C-language source code for the protocol modules was delivered to Goddard Space Flight Center for integration with the GSFC testbed. The need for a receiver autoconfiguration capability arises when a satellite-to-ground transmission is interrupted due to an unexpected event, the satellite transponder may reset to an unknown state and begin transmitting in a new mode. During Year 2, we completed testing of these algorithms when noise-induced bit errors were introduced. We also developed and tested an algorithm for estimating the data rate, assuming an NRZ-formatted signal corrupted with additive white Gaussian noise, and we took initial steps in integrating both algorithms into the SDR test bed at GSFC.

Horan Stephen; Lyman, Raphael

2005-01-01

112

Voice intelligibility in satellite mobile communications  

NASA Technical Reports Server (NTRS)

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.

Wishna, S.

1973-01-01

113

Fusion of digital television, broadband Internet and mobile communications - Part I: Enabling technologies  

Microsoft Academic Search

SUMMARY The introduction of digital video broadcasting (DVB) satellite systems has become an important tool for future mobile communication and is currently a focus in several research areas such as the integration of DVB satellite systems with different wireless technologies. This tutorial consists of two parts, Enabling technologies and Future service scenarios, which aims to provide an introduction to the

F. L. C. Ong; X. Liang; Prashant Pillai; P. M. L. Chan; Georgios Koltsidas; Fotini-Niovi Pavlidou; Erina Ferro; Alberto Gotta; Haitham S. Cruickshank; S. Iyengar; Gorry Fairhurst; V. Mancuso

2007-01-01

114

Satellite-aided mobile communications, experiments, applications and prospects  

NASA Technical Reports Server (NTRS)

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.

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

1980-01-01

115

A Mobile Communication Solution Based on Accessing Identifier  

Microsoft Academic Search

Internets has severe problem in security and mobility because it use the only unique source IP address and destination IP address during the process of communication all the time, IP address is overloaded in semantics because it is used to represent both the location and the identity of a user, so a new mechanism should be proposed. Although there are

Li Xiuqin; Lan Julong

2009-01-01

116

Anonymous and untraceable communications: Location privacy in mobile internetworking  

Microsoft Academic Search

Data protection and privacy is rapidly becoming one of the most important is- sues on the Internet today. Larger number of Internet sites are collecting personal information from users through forms, cookies, online registrations, or surveys than ever before. New commercial services are springing up that can exploit the ability of mobile communication service providers to determine the geographic location

Alberto Escudero Pascual

2001-01-01

117

An Interference Cancellation Scheme for Mobile Communication Radio Repeaters  

Microsoft Academic Search

An interference cancellation (ICAN) scheme for mobile communication radio repeaters is presented. When a radio repeater has a gain that is larger than the isolation between its transmit and receive antennas, it oscillates due to feedback interference signals. To prevent feedback oscillation of a radio repeater, we first formulate a feedback oscillation model of the radio repeater and then derive

Moohong Lee; Byungjik Keum; Young Serk Shim; Hwang Soo Lee

2009-01-01

118

A Model and Measure of Mobile Communication Competence  

ERIC Educational Resources Information Center

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…

Bakke, Emil

2010-01-01

119

Application of radio-over-fiber (ROF) in mobile communication  

Microsoft Academic Search

Future generation of mobile communication system must be capable of serving high quality and broadband services even in highly dense populated area. The radio-over-fibre is one of the promising systems which can be used along the emerging wireless technologies such as smart antenna or multiple input multiple output (MIMO) systems to meet these requirements. In this paper, the role of

Reza Abdolee; Razali Ngah; Vida Vakilian; Tharek A. Rahman

2007-01-01

120

Joint source-channel (de-)coding for mobile communications  

Microsoft Academic Search

Real world source coding algorithms usually leave a certain amount of redundancy within the coded bit stream. Shannon (1948) already mentioned that this redundancy can be exploited at the receiver side to achieve a higher robustness against channel errors. We show how joint source-channel decoding can be performed in a way that is applicable to any mobile communication system standard.

Tim Fingscheidt; Thomas Hindelang; Richard V. Cox; Nambi Seshadri

2002-01-01

121

Remotely controlled communication and control system for limited mobility individuals  

Microsoft Academic Search

Design improvements to a remotely controlled system for patients with limited mobility are described. This system provides communication and control of the room environment with mouse control that can be adapted to the functional need of the user. Analysis is provided on the selection and integration of components within the system as well as an overview of the simulated access

Matthew Goldman; Ettore Cervo; Alexander Melle; Bryan Wilson; Seyitriza Tigrek; Frank Agyei-Ntim; Kimberly E. Newman; Frank Barnes; Michael Blei

2011-01-01

122

Nationwide mobile communication systems, volume 1, chapters 1 thru 4  

Microsoft Academic Search

This thesis provides a basic understanding of nationwide terrestrial and satellite mobile communications and tracking technologies. Covered are systems currently available and in development. An analysis of user costs is performed for comparison. A more detailed satellite cost\\/benefit analysis for use by the trucking industry is also presented. Follow-on chapters contain discussions of the basic economic issues faces by satellite

William Joseph Schworer III

1990-01-01

123

Processing voice and data in mobile satellite communications  

Microsoft Academic Search

An on-line self adaptive scheme is required to overcome delays in voice transmission to mobile terminals in satellite communications systems. A method to combat specular multipath and increase signal processing capability for voice and data transmission is described, and system performance evaluated. A signal model is developed to account for transmission parameters, with attention to Gaussian variables. Finally, an optimum

T. P. McGarty; K. S. Schneider

1977-01-01

124

4-element printed array antenna for land mobile satellite communications  

Microsoft Academic Search

A high-efficiency four-element printed array antenna composed of one-point feed crossed-dipole printed elements with a reflector has been developed. The authors describe the design techniques of the antenna for INMARSAT mobile satellite communication system use and present experimental results

Y. Kazama; Sigeru MATSUMOTO; Hajime SHIROTORI; Tamotsu SUDA; Kenzo KASAMAKI

1992-01-01

125

Coherent versus noncoherent signaling for satellite-aided mobile communications  

NASA Technical Reports Server (NTRS)

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.

Davarian, F.; Sumida, J.

1986-01-01

126

The application of mobile satellite services to emergency response communications  

NASA Technical Reports Server (NTRS)

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.

Freibaum, J.

1980-01-01

127

Frequency diversity for OFDM mobile communication via underwater acoustic channels  

NASA Astrophysics Data System (ADS)

The major constraint on the performance of orthogonal frequency division multiplexing (OFDM) based underwater acoustic (UWA) communication is to keep subcarriers orthogonal. In this paper, Doppler estimation and the respective compensation technique along with various diversity techniques were deliberated for OFDM-based systems best suited for underwater wireless information exchange. In practice, for mobile communication, adjustment and tuning of transducers in order to get spatial diversity is extremely difficult. Considering the relatively low coherence bandwidth in UWA, the frequency diversity design with the Doppler compensation function was elaborated here. The outfield experiments of mobile underwater acoustic communication (UWAC) based on OFDM were carried out with 0.17 bit/(s·Hz) spectral efficiency. The validity and the dependability of the scheme were also analyzed.

Qiao, Gang; Wang, Wei; Guo, Ran; Khan, Rehan; Wang, Yue

2012-03-01

128

Research Priorities in Networking and Communications.  

ERIC Educational Resources Information Center

A workshop focused on major research issues in networking and communications. This report defines the context for research priorities and initiatives and deals with issues in networking and communications. Fifteen major research priorities and four research specific initiatives were identified by participants as areas that should be pursued over…

National Science Foundation, Washington, DC.

129

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

Federal Register 2010, 2011, 2012, 2013

...Mobile Communications Devices and Related Software; Final Determination Finding Violation...mobile communications devices and related software. The Commission has determined that...Apple Inc., and its subsidiary NeXT Software, Inc., both of Cupertino,...

2011-12-23

130

Consideration on minimizing the mass of communications equipments for the mobile communications satellite  

NASA Astrophysics Data System (ADS)

In mobile satellite communication, small and economical earth terminals can be employed if large satellite EIRP can be realized. In order to satisfy this requirement, a large antenna and high-power transponders are necessary; simultaneously reducing the mass of communication equipments in the satellite is required. In this paper, the relations between the total mass of communication equipment and the characteristics of the transponder and antenna in the satellite are derived. As a result, the optimum transponder output power, antenna diameter, and beam number which give large satellite EIRP with minimum mass of communication equipment, are obtained.

Dooi, Yoshikazu; Iso, Akio; Okubo, Naofumi; Sekine, Kenji; Baba, Yuichirou

131

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

NASA Astrophysics Data System (ADS)

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.

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

132

The Globalstar mobile satellite system for worldwide personal communications  

NASA Technical Reports Server (NTRS)

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.

Wiedeman, Robert A.; Viterbi, Andrew J.

1993-01-01

133

A wideband propagation simulator for high speed mobile radio communications  

NASA Astrophysics Data System (ADS)

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.

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

1994-07-01

134

Close Relationships: A Study of Mobile Communication Records  

NASA Astrophysics Data System (ADS)

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.

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

2013-05-01

135

Cockpit weather graphics using mobile satellite communications  

Microsoft Academic Search

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

Shashi Seth

1993-01-01

136

Why is CDMA the solution for mobile satellite communication  

NASA Technical Reports Server (NTRS)

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.

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

1989-01-01

137

Monitoring Heart Disease and Diabetes with Mobile Internet Communications  

PubMed Central

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.

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

2012-01-01

138

Feasibility study on radio communications using high altitude radio platform in the stratosphere - Applicability to mobile radio and coverage performance  

Microsoft Academic Search

It is possible that a platform, powered by microwaves beamed from the earth, carrying radio equipment and flying in the stratosphere, could be used for radio relay such as satellite communications, terrestrial microwave radio relay, land mobile base stations. In the Communication Research Laboratory, feasibility studies were started in 1989 on application of the high altitude radio platform (HARP) to

Taiji Saruwatari

1991-01-01

139

Mobile robotics research at Sandia National Laboratories  

SciTech Connect

Sandia is a National Security Laboratory providing scientific and engineering solutions to meet national needs for both government and industry. As part of this mission, the Intelligent Systems and Robotics Center conducts research and development in robotics and intelligent machine technologies. An overview of Sandia`s mobile robotics research is provided. Recent achievements and future directions in the areas of coordinated mobile manipulation, small smart machines, world modeling, and special application robots are presented.

Morse, W.D.

1998-09-01

140

Near field communication: getting in touch with mobile users.  

PubMed

Near field communication is a method for sending and receiving small amounts of data across very short distances wirelessly. This technology is already available in a number of mobile devices and has many possible uses, including electronic payment, access control, and information exchange. This article will explain the basic principles of near field communication, discuss some of the ways it can be used in libraries, and explore some possible concerns with the technology. A list of resources for additional information is also included. PMID:23869639

Hoy, Matthew B

2013-01-01

141

Peace Communication Research and the SCA Journals.  

ERIC Educational Resources Information Center

A preliminary study surveyed peace communication research in speech communication journals, covering the period from World War I through the late 20th century. The Matlon "Index" includes journals approved by the publications board of the Speech Communication Association (SCA) and was used in this project as the database for the period from 1915…

Kelley, Colleen E.

142

Neurotalk: improving the communication of neuroscience research  

Microsoft Academic Search

There is increasing pressure for neuroscientists to communicate their research and the societal implications of their findings to the public. Communicating science is challenging, and the transformation of communication by digital and interactive media increases the complexity of the challenge. To facilitate dialogue with the public in this new media landscape, we suggest three courses of action for the neuroscience

Mary Anne Moser; Jennifer B. McCormick; Eric Racine; Sandra Blakeslee; Arthur Caplan; Erika Check Hayden; Jay Ingram; Tiffany Lohwater; Peter McKnight; Christie Nicholson; Anthony Phillips; Kevin D. Sauvé; Elaine Snell; Samuel Weiss; Judy Illes

2009-01-01

143

FEC decoder design optimization for mobile satellite communications  

NASA Technical Reports Server (NTRS)

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).

Roy, Ashim; Lewi, Leng

1990-01-01

144

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

NASA Technical Reports Server (NTRS)

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.

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

1984-01-01

145

Trellis-coded CPM for satellite-based mobile communications  

NASA Technical Reports Server (NTRS)

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.

Abrishamkar, Farrokh; Biglieri, Ezio

1988-01-01

146

Rayleigh fading compensation for QAM in land mobile radio communications  

Microsoft Academic Search

A pilot symbol-aided Rayleigh fading compensation is investigated for M-ary quadrature amplitude modulation (QAM) to achieve highly spectrally efficient land mobile communication systems. The optimum parameters for fading compensation, bit error rate (BER) performance against Eb\\/N0 (energy per bit to the noise power spectrum density), adjacent channel interference, and cochannel interference for 16-QAM, 64-QAM, and 256-QAM, and the spectral efficiencies

Seiichi Sampei; Terumi Sunaga

1993-01-01

147

The Contemporary Relevance of Communication Research: Using "Communication Currents" in the Communication Curriculum  

ERIC Educational Resources Information Center

The purpose of this report is to describe a rationale and strategies for use of the National Communication Association's online magazine, "Communication Currents", in the undergraduate communication curriculum. "Communication Currents" features essays that translate current scholarship published in NCA journals, making the research "understandable…

Waldeck, Jennifer H.

2008-01-01

148

First satellite mobile communication trials using BLQS-CDMA  

NASA Technical Reports Server (NTRS)

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.

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

1993-01-01

149

Mobile satellite digital communications - Prodat and Standard C  

NASA Astrophysics Data System (ADS)

The ESA Prodat system aimed at demonstrating the usefulness of satellite communications for mobile users is outlined, and emphasis is placed on mobile terminals. The specifics of the land-mobile environment are discussed including open areas with no obstructions and partial and complete obstructions. A Prodat terminal connected to a handheld personal computer is described, along with its modes of operation: tracking and synchronization, standby mode when the link is interrupted, and acquisition mode. The second part of the paper is devoted to the development of an Inmarsat Standard C Ship Earth Station. A Standard C terminal is described, and attention is focused on microwave performance, a fading simulator, and Standard C demodulator. Error probability and performance characteristics are assessed.

Meuleman, F.; Glavieux, A.

150

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

PubMed Central

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 to communication with Solution Linked Group. Conclusions The use of mobile technology in this intervention took a leap from simply rendering information to providing more rapid services. Active participation of service providers along with mothers’ accessibility motivated both the service providers and mothers to communicate through mobile phone for maternal health issues. These altogether made the shift towards adoption of an innovation.

2014-01-01

151

Why phenomenology in communication research?  

Microsoft Academic Search

Phenomenology is, at the very least, a choice to study an environment from a situated location in actual experience and oriented toward particular aspects of the spectrum of human activity. Communication is, at the very least, a process of informing someone about something, and so forming and perhaps transforming both the environment and those who communicate within it in particular

Lenore Langsdorf

1994-01-01

152

Exploring the Concept of Mobile Viral Marketing through Case Study Research  

Microsoft Academic Search

Mobile viral marketing has a tremendous potential for communication and distribution purposes. Although seen as an important issue from the viewpoint of practitioners there has been little research on the phenomenon so far. This paper represents a first step in filling this void. We examine 34 case studies in order to identify relevant characteristics of mobile viral marketing. The outcome

Dietmar G. Wiedemann

2007-01-01

153

Finding Intercultural Business Communication Research Sites in Companies (Doing Research).  

ERIC Educational Resources Information Center

Describes important resources for discovering sites for communication research related to the North American Free Trade Agreement (NAFTA), to help identify appropriate companies and contact them. (SR)

Driskill, Linda; Shaw, Peggy

1994-01-01

154

Multivariate Analysis in Communication Research--Regression.  

ERIC Educational Resources Information Center

Multiple regression analysis is not beyond the reach of most researchers and research classes. It may prove beneficial to the communication researcher for a number of reasons. One of its most significant contributions to effective research is the utility of looking at several variables simultaneously. Another contribution of multiple regression…

Eli, Jack C.

155

PERCEPTIONS OF SECURITY AND PRIVACY WHEN USING MOBILE COMMUNICATION SYSTEMS An Analysis of Administrative and Line Staff Congruence  

Microsoft Academic Search

Mobile communication systems have revolutionized business communication and become common communication tools within business organizations. The dramatic increase in the use of mobile communication systems would not have been possible without the assumption of information security and privacy. However, in many workplaces, this assumption is wrong, and, in fact, mobile communications are vulnerable in many ways. The purpose of this

Cheon-Pyo Lee; Xin Luo; Merrill Warkentin

156

More About Lens Antenna For Mobile/Satellite Communication  

NASA Technical Reports Server (NTRS)

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.

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

1990-01-01

157

User requirements for interruption management in mobile communications in hospitals.  

PubMed

In hospitals, mobile communication devices increase the occurrence of inappropriate interruptions during clinical task performance. These interruptions have been related to decreased quality of clinical care. User requirements were elicited using a scenario based approach. The results present insights into user requirements for an interruption management system for hospitals. Hospital workflow protocols were identified as a major source of interruptions. Many suggestions for managing these interruptions related to improving workflow using IT. We have shown that even though the hospital is an exceptionally demanding environment, the user requirements for interruption management concur with earlier findings in the broader fields of context aware interruption management and computer supported cooperative work. PMID:23920869

Talsma, Bernd G; Solvoll, Terje; Hartvigsen, Gunnar

2013-01-01

158

Omni-directional L-band antenna for mobile communications  

NASA Technical Reports Server (NTRS)

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.

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

1988-01-01

159

Channel Modelling and Characterization of Mobile Satellite Communication Systems  

NASA Astrophysics Data System (ADS)

Reliable characterization of the propagation environment and channel modelling of mobile satellite communication systems is necessary in order to provide better quality of service and efficient design of these systems. In this paper, the channel impairments affecting the performance and an overview of the satellite channel models are presented. The statistical distributions of the received signal that can be used to characterize the dynamic nature of these propagation channels are also presented. The main modelling parameters are investigated and simulation results show that the bit error rate (BER) performance is predominantly affected by the shadowing factor. Finally, in order to further test the channel models and the effect of the propagation environment, we investigate a novel application of using satellite diversity in conjunction with compact MIMO (multiple-input multiple-output) antenna array configurations in order to enhance the capacity of satellite communication links.

Mohammed, Abbas; Seun, Ajayi; Yang, Zhe; Erman, Maria; Hult, Tommy

2009-03-01

160

Grounding Mobility Research ? Ideas for a Research Agenda  

Microsoft Academic Search

Research into mobile business has grown significantly over the last decade, but seemingly in a haphazard and not always rigorous fashion. This was first observed in 2003 and then borne out by an in-depth analysis of hundreds of m-business research publications in 2006. Four years on, these notions and findings still suggest that a direction of future research with a

Hans Lehmann; Eusebio Scornavacca

2010-01-01

161

Optical Communications Research at Institute of Telecommunications  

Microsoft Academic Search

In this contribution we present a brief summary of research activities carried out at Instituto de Telecomunicaç;ões (IT, Institute of Telecommunications) in optical communications. These activities cover various aspects related with optical components\\/subsystems, optical communication systems, and optical networking.

J. F. Rocha; A. T. Cartaxo; H. J. Silva; J. L. Pinto; A. Le Teixeira; A. S. Gameiro; P. P. Monteiro; J. O. Pires; R. S. Ribeiro; M. O. Violas; A. N. Pinto; M. N. Lima; P. S. André; M. M. Freire; A. L. Ribeiro; C. F. Fernandes; J. T. Pereira; J. M. Pousa; J. M. Santos; M. T. Almeida; A. R. Tavares; R. N. Nogueira; J. S. Machado

2005-01-01

162

Towards Verifying Communication Research in Healthcare  

Microsoft Academic Search

On the basis of international and Hungarian studies and research results, the subject of this paper is health care, moving towards a bio-psycho-social model, meanwhile struggling with financing problems. In medical attendance, an increasing attention is paid to risk communication and user satisfaction: appropriate communication and involving patients into decisions are more and more considered as factors that assist the

Beata Vajda

2010-01-01

163

Patient-centered Communication Research  

Cancer.gov

Several recent reports, including NCI's Strategic Plan for Leading the Nation and the NCI-designated cancer center directors' report Accelerating Successes Against Cancer, have recognized the salience of patient-clinician communication in optimizing cancer patients' and survivors' health outcomes.

164

Driving forces of researchers mobility.  

PubMed

Starting from the dataset of the publication corpus of the APS during the period 1955-2009, we reconstruct the individual researchers trajectories, namely the list of the consecutive affiliations for each scholar. Crossing this information with different geographic datasets we embed these trajectories in a spatial framework. Using methods from network theory and complex systems analysis we characterise these patterns in terms of topological network properties and we analyse the dependence of an academic path across different dimensions: the distance between two subsequent positions, the relative importance of the institutions (in terms of number of publications) and some socio-cultural traits. We show that distance is not always a good predictor for the next affiliation while other factors like "the previous steps" of the career of the researchers (in particular the first position) or the linguistic and historical similarity between two countries can have an important impact. Finally we show that the dataset exhibit a memory effect, hence the fate of a career strongly depends from the first two affiliations. PMID:24810800

Gargiulo, Floriana; Carletti, Timoteo

2014-01-01

165

Driving forces of researchers mobility  

NASA Astrophysics Data System (ADS)

Starting from the dataset of the publication corpus of the APS during the period 1955-2009, we reconstruct the individual researchers trajectories, namely the list of the consecutive affiliations for each scholar. Crossing this information with different geographic datasets we embed these trajectories in a spatial framework. Using methods from network theory and complex systems analysis we characterise these patterns in terms of topological network properties and we analyse the dependence of an academic path across different dimensions: the distance between two subsequent positions, the relative importance of the institutions (in terms of number of publications) and some socio-cultural traits. We show that distance is not always a good predictor for the next affiliation while other factors like ``the previous steps'' of the career of the researchers (in particular the first position) or the linguistic and historical similarity between two countries can have an important impact. Finally we show that the dataset exhibit a memory effect, hence the fate of a career strongly depends from the first two affiliations.

Gargiulo, Floriana; Carletti, Timoteo

2014-05-01

166

Driving forces of researchers mobility  

PubMed Central

Starting from the dataset of the publication corpus of the APS during the period 1955–2009, we reconstruct the individual researchers trajectories, namely the list of the consecutive affiliations for each scholar. Crossing this information with different geographic datasets we embed these trajectories in a spatial framework. Using methods from network theory and complex systems analysis we characterise these patterns in terms of topological network properties and we analyse the dependence of an academic path across different dimensions: the distance between two subsequent positions, the relative importance of the institutions (in terms of number of publications) and some socio–cultural traits. We show that distance is not always a good predictor for the next affiliation while other factors like “the previous steps” of the career of the researchers (in particular the first position) or the linguistic and historical similarity between two countries can have an important impact. Finally we show that the dataset exhibit a memory effect, hence the fate of a career strongly depends from the first two affiliations.

Gargiulo, Floriana; Carletti, Timoteo

2014-01-01

167

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

ERIC Educational Resources Information Center

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…

Ogara, Solomon Omondi

2011-01-01

168

Radial microstrip slotline feed network for circular mobile communications array  

NASA Astrophysics Data System (ADS)

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.

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

1994-04-01

169

Robust Timing Synchronization in Aeronautical Mobile Communication Systems  

NASA Technical Reports Server (NTRS)

This work details a study of robust synchronization schemes suitable for satellite to mobile aeronautical applications. A new scheme, the Modified Sliding Window Synchronizer (MSWS), is devised and compared with existing schemes, including the traditional Early-Late Gate Synchronizer (ELGS), the Gardner Zero-Crossing Detector (GZCD), and the Sliding Window Synchronizer (SWS). Performance of the synchronization schemes is evaluated by a set of metrics that indicate performance in digital communications systems. The metrics are convergence time, mean square phase error (or root mean-square phase error), lowest SNR for locking, initial frequency offset performance, midstream frequency offset performance, and system complexity. The performance of the synchronizers is evaluated by means of Matlab simulation models. A simulation platform is devised to model the satellite to mobile aeronautical channel, consisting of a Quadrature Phase Shift Keying modulator, an additive white Gaussian noise channel, and a demodulator front end. Simulation results show that the MSWS provides the most robust performance at the cost of system complexity. The GZCD provides a good tradeoff between robustness and system complexity for communication systems that require high symbol rates or low overall system costs. The ELGS has a high system complexity despite its average performance. Overall, the SWS, originally designed for multi-carrier systems, performs very poorly in single-carrier communications systems. Table 5.1 in Section 5 provides a ranking of each of the synchronization schemes in terms of the metrics set forth in Section 4.1. Details of comparison are given in Section 5. Based on the results presented in Table 5, it is safe to say that the most robust synchronization scheme examined in this work is the high-sample-rate Modified Sliding Window Synchronizer. A close second is its low-sample-rate cousin. The tradeoff between complexity and lowest mean-square phase error determines 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.

Xiong, Fu-Qin; Pinchak, Stanley

2004-01-01

170

A review of earth observation using mobile personal communication devices  

NASA Astrophysics Data System (ADS)

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.

Ferster, Colin J.; Coops, Nicholas C.

2013-02-01

171

Traditional and Mobile Public Health Alert Communications with Health Care Providers  

PubMed Central

Objective To systematically compare mobile (SMS) and traditional (email, FAX) communication strategies to identify which modality is most effective for communication of health alerts and advisories between public health agencies and health care providers in order to improve emergency preparedness and response. Introduction The effectiveness of emergency preparedness and response systems depends, in part, on the effectiveness of communication between agencies and individuals involved in emergency response, including health care providers who play a significant role in planning, event detection, response and communication with the public. Although much attention has been paid to the importance of communicating clinical data from health care providers to public health agencies for purposes of early event detection and situational awareness (e.g., BioSense) and to the need for alerting health care providers of public health events (e.g., Health Alert Networks), no studies to date have systematically identified the most effective methods of communication between public health agencies and community health care providers for purposes of public health emergency preparedness and response. The REACH (Rapid Emergency Alert Communication in Health) study is a 4-year randomized controlled trial to evaluate and compare the effectiveness of mobile (SMS) and traditional (email, FAX) communication strategies for sending public health messages to health care providers—physicians, pharmacists, nurse practitioners, physician’s assistants and veterinarians. Methods Providers were recruited from three sites (King County, WA; Spokane County, WA; and across the state of Montana; N=845) and randomized to receive time-sensitive public health messages via email, Fax, short message service (SMS) or to a control group that did not receive messages. For one year, alerts based on real events of public health interest were sent quarterly with follow-up telephone interviews conducted 5–10 days after the delivery date. Interviews consisted of approximately six questions that elicited information about message receipt, recall of its content and perceived credibility and trustworthiness of the message and source. In addition, provider access to online alert information and delivery success or failure was collected. Results Frequency of receipt, timeliness, content awareness, perceived credibility and perceived trustworthiness were measured and compared across communication delivery systems. On average 84.0% of participants were contacted in each follow-up survey following all alerts and across all three sites. Primary data analysis was designed to measure differences between the three communication groups using intent-to-treat methods. A set of secondary analyses examined the outcomes excluding providers who could not have received messages (due to incorrect contact information, known technical failures, or because providers could not receive messages by the assigned delivery message—for example, a provider without a Fax number randomized to the Fax group). We will discuss preliminary results of intent-to-treat analyses regarding rate of recall of study alert message content between traditional and mobile communications and perceived trustworthiness and credibility of message and message source by providers. In addition, we will report on frequency of accessing online alert information between traditional and mobile delivery groups. Conclusions There is currently no evidence-based research to guide or improve the practice of public health communication between public health agencies and health care providers before, during and after a public health emergency. Improving this communication via the use of effective media can enhance disease surveillance, which will aid in early detection and enhance case finding and situational awareness for public health emergencies. By systematically evaluating the relative effectiveness of mobile and traditional message delivery systems for emergency preparedness and response communications, th

Revere, Debra; Painter, Ian; Baseman, Janet

2013-01-01

172

Broadband and scalable mobile satellite communication system for future access networks  

NASA Astrophysics Data System (ADS)

Due to the recent market trends, NTT has begun research into next generation satellite communication systems, such as broadband and scalable mobile communication systems. One service application objective is to provide broadband Internet access for transportation systems, temporal broadband access networks and telemetries to remote areas. While these are niche markets the total amount of capacity should be significant. We set a 1-Gb/s total transmission capacity as our goal. Our key concern is the system cost, which means that the system should be unified system with diversified services and not tailored for each application. As satellites account for a large portion of the total system cost, we set the target satellite size as a small, one-ton class dry mass with a 2-kW class payload power. In addition to the payload power and weight, the mobile satellite's frequency band is extremely limited. Therefore, we need to develop innovative technologies that will reduce the weight and maximize spectrum and power efficiency. Another challenge is the need for the system to handle up to 50 dB and a wide data rate range of other applications. This paper describes the key communication system technologies; the frequency reuse strategy, multiplexing scheme, resource allocation scheme, and QoS management algorithm to ensure excellent spectrum efficiency and support a variety of services and quality requirements in the mobile environment.

Ohata, Kohei; Kobayashi, Kiyoshi; Nakahira, Katsuya; Ueba, Masazumi

2005-07-01

173

Communicating Qualitative Research Study Designs to Research Ethics Review Boards  

ERIC Educational Resources Information Center

Researchers using qualitative methodologies appear to be particularly prone to having their study designs called into question by research ethics or funding agency review committees. In this paper, the author considers the issue of communicating qualitative research study designs in the context of institutional research ethics review and offers…

Ells, Carolyn

2011-01-01

174

Isolated and coupled superquadric loop antennas for mobile communications applications  

NASA Astrophysics Data System (ADS)

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.

Jensen, Michael A.; Rahmat-Samii, Yahya

175

Considerations of digital phase modulation for narrowband satellite mobile communication  

NASA Technical Reports Server (NTRS)

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.

Grythe, Knut

1990-01-01

176

Speech coding at 4800 bps for mobile satellite communications  

NASA Technical Reports Server (NTRS)

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.

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

1988-01-01

177

Isolated and coupled superquadric loop antennas for mobile communications applications  

NASA Technical Reports Server (NTRS)

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.

Jensen, Michael A.; Rahmat-Samii, Yahya

1993-01-01

178

Adaptive beamforming in a CDMA mobile satellite communications system  

NASA Technical Reports Server (NTRS)

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.

Munoz-Garcia, Samuel G.

1993-01-01

179

Efficient simulation of TCP\\/IP for mobile wireless communications using importance sampling  

Microsoft Academic Search

Future military communications systems are expected to exchange information in a seamless and reliable manner across heterogeneous networks composed of both fixed, wired nodes and mobile, wireless nodes. While commercial protocols such as TCP\\/IP have improved the seamlessness of military communications systems, the use of TCP\\/IP in the mobile, wireless environment for which it was not designed can have a

Zsolt Haraszti; J. Keith Townsend; James A. Freebersyser

1998-01-01

180

A study and experiment plan for digital mobile communication via satellite  

Microsoft Academic Search

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

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

1978-01-01

181

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

ERIC Educational Resources Information Center

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.…

Beaubrun, Ronald; Pierre, Samuel

2001-01-01

182

Mobile forms of communication and the transformation of relations between the public and private spheres  

Microsoft Academic Search

Mobile communications have transformed the way people interact in those countries where technology, economics and policy have intersected to foster its profusion. That much would appear self-evident. Anecdotally we can call up a host of archetypal instances of mobile communications impacting upon our everyday lives in ways which less than two decades ago (in an age of fixed-line telephony) would

Bob Jeffery

183

Development of a cheap on-board vision mobile robot for robotic soccer research  

Microsoft Academic Search

To promote robotic soccer research, we need a low cost and portable robot with some sensors and a communication device. To date, there is no platform for robotic soccer. Therefore, each research must build his own robots or utilize robots which are commercially available. This paper describes how to construct a robot system which includes a lightweight and low-cost mobile

T. Nakamura; K. Terada; A. Shibata; J. Morimoto; H. Adachi; H. Takeda

1998-01-01

184

Development of a mobile research flight test support capability  

NASA Technical Reports Server (NTRS)

This paper presents the approach taken by the NASA Western Aeronautical Test Range (WATR) of the Ames Research Center to develop and utilize mobile systems to satisfy unique real-time research flight test requirements of research projects such as the advanced fighter technology integration (AFTI)F-16, YAV-8B Harrier, F-18 high-alpha research vehicle (HARV), XV-15, and the UH-60 Black Hawk. The approach taken is cost-effective, staff efficient, technologically current, and provides a safe and effective research flight test environment to support a highly complex set of real-time requirements including the areas of tracking and data acquisition, communications (audio and video) and real-time processing and display, postmission processing, and command uplink. The development of this capability has been in response to the need for rapid deployment at varied site locations with full real-time computations and display capability. This paper will discuss the requirements, implementation and growth plan for mobile systems development within the NASA Western Aeronautical Test Range.

Rhea, Donald C.; Moore, Archie L.

1988-01-01

185

A Review on Terahertz Communications Research  

NASA Astrophysics Data System (ADS)

The increasing demand of unoccupied and unregulated bandwidth for wireless communication systems will inevitably lead to the extension of operation frequencies toward the lower THz frequency range. Higher carrier frequencies will allow for fast transmission of huge amounts of data as needed for new emerging applications. Despite the tremendous hurdles that have to be overcome with regard to sources and detectors, circuit and antenna technology and system architecture to realize ultrafast data transmission in a scenario with extensive transmission loss, a new area of research is beginning to form. In this article we give an overview of emerging technologies and system research that might lead to ubiquitous THz communication systems in the future.

Kleine-Ostmann, Thomas; Nagatsuma, Tadao

2011-02-01

186

Low and Medium-Gain antennas for Mobile Satellite Communications (MSC) and Navigation  

Microsoft Academic Search

In this paper are introduced Low-Gain Omnidirectional Antennas for Mobile Satellite Communications (MSC) and Navigation. In many respects the Mobile Satellite Antenna (MSA) infrastructures currently available for MSC and Navigation. Medium and high gain MSA need to track the satellite, following both movements of mobiles and satellite orbital motions. Sometimes this is difficult and expensive to synchronize and have to

Stojce Dimov Ilcev

2011-01-01

187

Life Cycle Assessment of the Mobile Communication System UMTS: Towards Eco-efficient Systems (12 pp)  

Microsoft Academic Search

Goal, Scope and Background   Goal of this study is an evaluation of the environmental sustainability of the UMTS mobile communication system in Switzerland\\u000a by means of a Life Cycle Assessment (LCA). A baseline environmental impact profile across the full life cycle of the UMTS\\u000a (Universal Mobile Telecommunication System) and its predecessor, the GSM (Global System for Mobile Communication) is presented.

Mireille Faist Emmenegger; Rolf Frischknecht; Markus Stutz; Michael Guggisberg; Res Witschi; Tim Otto

2006-01-01

188

A Analysis of Noise and Interference in a Satellite Based Mobile Communications System  

Microsoft Academic Search

In any satellite-to-mobile or mobile-to-mobile communications system, the effects of fading, propagation path loss, noise, interference, and non-linearities on the signal have to be considered. The basic problem is to evaluate the performance of such a communications link for various signaling schemes. However, the multitude of the noise, attenuation and interference effects described above would introduce so many variables that

Shalom Solomon Bergstein

1983-01-01

189

An analysis of noise and interference in a satellite based mobile communications system  

Microsoft Academic Search

In any satellite-to-mobile or mobile-to-mobile communications system, the effects of fading, propagation path loss, noise, interference, and non-linearities on the signal have to be considered. The basic problem is to evaluate the performance of such a communications link for various signaling schemes. However, the multitude of the noise, attenuation and interference effects described above would introduce so many variables that

S. S. Bergstein

1983-01-01

190

How can we use mobile apps for disaster communications in Taiwan: Problems and possible practice  

Microsoft Academic Search

The growth rate of global smart phone in 2010 is as high as 78.1%, showing that smart phone gradually becomes the mainstream in the mobile phone market. Smart phone has the function of installing applications, provides users with more diversified mobile value-added services and will change users' communication habits in the future. Mobile communication follows the development trend of 3G

Sz Jie Sung

2011-01-01

191

Two-Armed, Mobile, Sensate Research Robot  

NASA Technical Reports Server (NTRS)

The Anthropomorphic Robotic Testbed (ART) is an experimental prototype of a partly anthropomorphic, humanoid-size, mobile robot. The basic ART design concept provides for a combination of two-armed coordination, tactility, stereoscopic vision, mobility with navigation and avoidance of obstacles, and natural-language communication, so that the ART could emulate humans in many activities. The ART could be developed into a variety of highly capable robotic assistants for general or specific applications. There is especially great potential for the development of ART-based robots as substitutes for live-in health-care aides for home-bound persons who are aged, infirm, or physically handicapped; these robots could greatly reduce the cost of home health care and extend the term of independent living. The ART is a fully autonomous and untethered system. It includes a mobile base on which is mounted an extensible torso topped by a head, shoulders, and two arms. All subsystems of the ART are powered by a rechargeable, removable battery pack. The mobile base is a differentially- driven, nonholonomic vehicle capable of a speed >1 m/s and can handle a payload >100 kg. The base can be controlled manually, in forward/backward and/or simultaneous rotational motion, by use of a joystick. Alternatively, the motion of the base can be controlled autonomously by an onboard navigational computer. By retraction or extension of the torso, the head height of the ART can be adjusted from 5 ft (1.5 m) to 6 1/2 ft (2 m), so that the arms can reach either the floor or high shelves, or some ceilings. The arms are symmetrical. Each arm (including the wrist) has a total of six rotary axes like those of the human shoulder, elbow, and wrist joints. The arms are actuated by electric motors in combination with brakes and gas-spring assists on the shoulder and elbow joints. The arms are operated under closed-loop digital control. A receptacle for an end effector is mounted on the tip of the wrist and contains a force-and-torque sensor that provides feedback for force (compliance) control of the arm. The end effector could be a tool or a robot hand, depending on the application.

Engelberger, J. F.; Roberts, W. Nelson; Ryan, David J.; Silverthorne, Andrew

2004-01-01

192

77 FR 40399 - Qiao Xing Universal Resources, Inc., and Qiao Xing Mobile Communication Co., Ltd.; Order of...  

Federal Register 2010, 2011, 2012, 2013

...Xing Universal Resources, Inc., and Qiao Xing Mobile Communication Co., Ltd.; Order of Suspension of Trading July...information concerning the securities of Qiao Xing Mobile Communication Co., Ltd. (``QXM''), a British...

2012-07-09

193

Communication Apprehension: A Preliminary Bibliography of Research.  

ERIC Educational Resources Information Center

This 243-item bibliography represents a preliminary step in the collection and synthesis of research in communication apprehension. No qualitative criteria were used in the selection of items for this bibliography, except that the item had to deal with apprehension as a major part of the report. Basic texts that mention apprehension but that do…

Daly, John A.

194

Multivariate Multiple Regression in Communication Research.  

ERIC Educational Resources Information Center

This paper examines the multivariate multiple regression model and explores its applicability to communication research. The first section discusses partitioning of a data matrix, as a heuristic device for distinguishing among alternative regression models. Section two examines various aspects of univariate multiple regression, including the form…

Monge, Peter R.

195

Computer networks in communication survey research  

Microsoft Academic Search

The paper explores the feasibility of using computer networks as communication survey research instruments. Also covered are the use of computers and computer networks in survey studies; a listing of the advantages and disadvantages of network surveys as compared with mail, phone, and fax surveys; a description of the development steps of network surveys; and a comparison of differences in

Chien Chou

1997-01-01

196

Study on Communication between Home and School System Based on Mobile Education Platform  

Microsoft Academic Search

As the two significant sides of the education, it is all-important to communicate and intercourse between the home and school. With the development of the information and the internet, Notebook computers, mobile phones and other modern communications equipments continues to increase, they are constructing the timely exchange of information and the emotion platform. So this article firstly introduces the communication

Weifeng Jiao; Jialing Zhao

2007-01-01

197

Placement of UAVs as Communication Relays Aiding Mobile Ad Hoc Wireless Networks  

Microsoft Academic Search

Unmanned aerial vehicles (UAVs) have been used for surveillance and reconnaaissance operations. Such communications enabled platforms can also be effectively utilized to enhance the communications transport capabilitites of a mobile ad hoc wireless network. When properly embedded into the architecture of a communications network, the resultirng UAV aided terrestrial network architecture is expended into a multi-layered hierarchical network structure. The

Izhak Rubin; Runhe Zhang

2007-01-01

198

Technical design and service aspects of digital mobile satellite communication systems  

Microsoft Academic Search

The key technical elements in designing digital mobile satellite communication systems are identified, and tradeoff studies on the transmission parameters of the satellite link, which were based on experience with an experimental system and the results of field trials, on digital maritime and aeronautical satellite communication systems, are described. The future evolution of the various new communication services to be

Yutaka YASUDA; Masayoshi OHASHI; Fumiaki SUGAYA; Yasuo HIRATA

1988-01-01

199

Research in space commercialization, technology transfer, and communications, volume 2  

NASA Technical Reports Server (NTRS)

Spectrum management, models for evaluating communication systems, the communications regulatory environment, expert prediction and consensus, remote sensing, and manned space operations research are discussed.

Dunn, D. A.; Agnew, C. E.

1983-01-01

200

Mobile phones and driving: a review of contemporary research  

Microsoft Academic Search

This study reviews research on the effects of using a mobile phone when driving. First, it is should be pointed out that the availability of a mobile phone in a car is of great value, for example, in emergencies and accidents. However, the results from the research covered in this review show that using a mobile phone in a car

Ola Svenson; Christopher J. D. Patten

2005-01-01

201

Adaptive digital beamforming for a CDMA mobile communications payload  

NASA Technical Reports Server (NTRS)

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 reference signal highly correlated with the desired user signal and uncorrelated with the interferences. CDMA lends itself very easily to the generation of such a reference signal, thanks to the a priori knowledge of the user's signature sequence. First, the integration of an adaptive antenna in an asynchronous CDMA system is analyzed. The adaptive antenna system can provide increased interference rejection - much higher than that afforded by the code alone - and, since CDMA is mainly interference limited, any reduction in interference converts directly and linearly into an increase in capacity. Analyses and computer simulations are presented that show how an asynchronous CDMA system incorporating adaptive beamforming can provide at least as much capacity as a synchronous system. More importantly, the proposed concept allows the near-far effect to be mitigated without requiring a tight coordination of the users in terms of transmitted power control or network synchronization. The system is extremely robust to the near-far effect because the signals reaching the satellite from directions other than that of the desired user - which are likely to have different power levels - are adaptively canceled by the antenna. Finally, a payload architecture is presented that illustrates the practical implementation of this concept. This digital payload architecture demonstrates 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.

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

1993-01-01

202

Federal research and development for satellite communications  

NASA Technical Reports Server (NTRS)

A Committee on Satellite Communication (COSC) was formed under the auspices of the Space Applications Board (SAB) in order to study Federal research and development on satellite communications (SC). Discussion on whether to continue the research and development and the proper role of the Federal Government are addressed. Discussion focussed on six possible options for a Federal role in SC research and development: (1) the current NASA SC program; (2) an expanded NASA SC technology program; (3) a SC technology flight test support program; (4) an experimental SC technology flight program; (5) an experimental public service SC system program; and (6) an operational public service SC system program. Decision criteria and recommendations are presented.

1977-01-01

203

Control over social interactions: an important reason for young people's use of the Internet and mobile phones for communication?  

PubMed

This paper reports some research that was undertaken to determine why young people choose to use certain communication media, especially the Internet and mobile phones for social purposes. Focus group methodology was employed in achieving this aim. Specifically, two focus groups containing young people aged 18-20 years were asked to discuss the question "why do you use different communication media, such as the Internet and mobile phones, in your social lives?" Discussions from the sessions were recorded on audiotapes, and then transcribed, and analyzed according to the principles of Grounded Theory. A number of categories emerged from the data. The most significant category indicated that young people often liked to use communication media such as the Internet and mobile phones to communicate because these afforded them control over their interactions. In particular, the data seemed to suggest that participants felt that because some communication media such as email, text messaging and instant messaging can be used asynchronously as well as synchronously, they allow one time to stop and think before giving a response if this is desired, or, alternatively, allowed one to retain the conversational nature of interactions if this is preferred. This gave participants greater control over interactions than they would have if, say, communicating via voice calls using the telephone or face-to-face, which are necessarily synchronous. PMID:17305461

Madell, Dominic E; Muncer, Steven J

2007-02-01

204

An Interference Cancellation Scheme for Mobile Communication Radio Repeaters  

NASA Astrophysics Data System (ADS)

An interference cancellation (ICAN) scheme for mobile communication radio repeaters is presented. When a radio repeater has a gain that is larger than the isolation between its transmit and receive antennas, it oscillates due to feedback interference signals. To prevent feedback oscillation of a radio repeater, we first formulate a feedback oscillation model of the radio repeater and then derive an ICAN model from that model. From the derived ICAN model, we show that the stability and the signal quality of the repeater depend on the repeater's gain and delay, the propagation delay on feedback paths, feedback channel characteristics, and the capability of the feedback channel estimation algorithm. It is also shown that the stability condition of the repeater does not guarantee the quality of the repeater's output signal. To guarantee repeater's stability and signal quality, an ICAN scheme based on an iterative algorithm is subsequently proposed. The simulation results confirm the relationship between the stability and signal quality of the repeater and the impact of the aforementioned factors. Using the proposed ICAN scheme, a mean error vector magnitude (quality indicator) of about 6.3% for the repeater's output signal was achieved.

Lee, Moohong; Keum, Byungjik; Shim, Young Serk; Lee, Hwang Soo

205

L-band antennas for regional mobile communication satellites  

NASA Astrophysics Data System (ADS)

Satellite L-band antennas ranging for state of the art small reflector systems to multibeam arrays, to large array-fed reflectors, with frequency reuse, flexible channel to beam allocation and/or steerable beam capabilities over an extended European coverage are reviewed. Both 2.5 to 5 m multifeed reflectors and foldable multibeam arrays are valid candidates for regional mobile communication satellites in the next decade. The foldable multibeam arrays have the major advantage over the multifeed reflectors of quasi-total traffic to beam allocation flexibility. In the longer term, when increase in traffic is such that on board minimum gains greater than 35 dBi are required, unfurlable reflectors with diameters greater than 10 m are preferable, since direct radiating arrays with equivalent aperture area cannot easily be deployed. Technologies for foldable arrays and reflectors up to 5 m diameter should be available for flight in the early nineties from present hardware developments. The same technology is applicable up to greater than 10 m, but with a serious additional effort required, particularly in testing.

Roederer, A.

1986-09-01

206

David Florida Laboratory: Support for mobile satellite communications  

NASA Technical Reports Server (NTRS)

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.

Dumoulin, Jean-Guy; Mamen, Rolf

1995-01-01

207

University research reactors and Internet communication  

SciTech Connect

In July 1993, the U.S. Nuclear Regulatory Commission (NRC) stunned nonprofit U.S. universities by eliminating the historical fee exemption for these entities. The fees would have devastating effects on university reactor operations and university by-product material usage. Faced with the prospect of eliminating their programs, the university research reactor (URR) community made a concerted response to reinstate the exemption. While the effort eventually proved successful, the need for fast and efficient communication became very apparent during the crisis. One outcome was an effort to enhance communications among the university reactors by using electronic mail (E-mail) on the Internet. This paper describes how the fee crisis demonstrated the need for enhanced communications and the results of the effort to provide it.

Bobek, L.M.

1994-12-31

208

The role of interpersonal communication in the process of knowledge mobilization within a community-based organization: a network analysis  

PubMed Central

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?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.

2014-01-01

209

Research on Mobile IP Routing of Space Network that Based on IP over CCSDS  

Microsoft Academic Search

Space wideband information network technology is one of the hot technologies in studying of space technology, there are many difficult technologies need to be solved, for example, technologies of the connection and communication between space and ground heterogeneous network, algorithm of mobile routing, etc. The paper does research on these problems based on IP technology of the ground network and

Li-zheng Jiang; Xin Meng; Sheng-bo Hu; Shu-qian Liu

2007-01-01

210

Concepts of "Culture": Implications for Intercultural Communication Research.  

ERIC Educational Resources Information Center

Reviews intercultural communication research as it is published by communication journals. Examines how culture is conceptualized in intercultural communication research. Discusses alternate ways in which "culture" might be conceptualized and explores the consequences that this might have for intercultural communication scholarship. (SR)

Moon, Dreama G.

1996-01-01

211

Effect Size Reporting Practices in Communication Research  

Microsoft Academic Search

In recent years, reporting estimates of effect size have become more important in social and behavioral science research. Four full volumes (2003–2006) of four influential communication journals were examined. The findings show that the rate of reporting effect size was very high for some types of statistical analyses (e.g., correlation, regression), and considerably lower for others (e.g., t-test, ? test).

Shaojing Sun; Xitao Fan

2010-01-01

212

A Survey of Routing Techniques for Mobile Communications Networks  

Microsoft Academic Search

. Mobile wireless networks pose interesting challenges for routing system design. To producefeasible routes in a mobile wireless network, a routing system must be able to accommodate roving users,changing network topology, and fluctuating link quality. We discuss the impact of node mobility and wirelesscommunication on routing system design, and we survey the set of techniques employed in or proposed forrouting

S. Ramanathan; Martha Steenstrup

1996-01-01

213

Research and development opportunities in mobile satellite technologies  

NASA Astrophysics Data System (ADS)

An assessment is made of the prospective services that could be advantageously furnished in a country as large as Australia by Mobile Satellite Service-based communications systems, as well as of the technology requirements of such systems. The key technologies in question are spacecraft UHF antennas, high-power onboard UHF amplifiers, mobile ground antennas, FDMA and CDMA multiple access techniques, and channel characterization. An evaluation is made of possible Australian R&D participation in Inmarsat Standard-C ship earth station, the Personal Mobile Satellite Alphanumeric Paging Terminal, and analog and digital modems for narrowband mobile satellite channels.

Manh, Q. D.

214

A Study on the Role of Mobile Phone Communication in Tuberculosis DOTS Treatment  

PubMed Central

Background: Every year, a lot of Tuberculosis (TB) patients undergo Directly Observed Treatment Short-course (DOTS) in Salem city, one of the high TB districts in South India. Mobile phone usage among these patients and health workers is common. Mobile phone communication has a great potential in TB treatment. Objectives: To analyze the mobile phone usage and its effectiveness in TB DOTS treatment. Materials and Methods: A cross-sectional survey with 150 TB patients was followed by a focus group discussion with treatment supervisors, DOTS providers, and health workers. Results: Majority of patients use mobile phones to make calls to health workers to clarify their doubts on side effects, food, and symptoms of the disease. TB treatment supervisors effectively use mobile phones to counsel patients to adhere to the treatment regimen. Patients see mobile phones as a useful communication tool in TB treatment though they prefer direct interpersonal communication with health workers. Though the mobile ownership is 68% among the TB patients, many of them are not able to send text messages or read messages in English. Conclusion: Mobile phone possession and usage is high among the patients. Patients need to be trained to use mobile phone features such as alarm, voice mail, and interactive voice response. Incentives like free talk time and short message service (SMS) will encourage patients to communicate frequently with health workers, thereby, increasing the chances of better adherence to DOTS. SMS could be made available in the regional languages.

Elangovan, R; Arulchelvan, S

2013-01-01

215

Application of smart antennas in CDMA mobile communication system  

NASA Astrophysics Data System (ADS)

Full coverage in mobile service region will elate mobile telephone customers. Limited frequency resources make mobile system capacity poor. High capacity and full coverage are two main key problems for system design. CDMA system has advantage of customer capacity, and Antenna array brings its coverage ability and intelligence into full play. Smart antenna combined with code division multiple access will improve mobile telecom system performance. Increasing system performance and capacity appear through enhancing desired signal and suppressing interference signals. Several kinds of antenna array techniques including beam forming, diversity, switched-beam antenna array and sectorization were discussed here in detail. The small antenna applications in TDMA mobile telecommunication systems are also discussed.

Guo, Congliang; Zhou, Yingui; Liu, Tonghui; Wang, Rongsheng; Liu, Shijian

2001-10-01

216

The research of mobile application user experience and assessment model  

Microsoft Academic Search

This essay mainly study mobile application user experience and quantitative assessment through Analytic Hierarchy Process. On the basis of the relational studies, this paper put forward four-dimensional assessment system of mobile application user experience. That is: user characteristics, App properties, App system supports and context parameters. What's more, combining user research, paper offers a comprehensive hierarchy criterion framework for mobile

Zhi Chen; Shangshang Zhu

2011-01-01

217

Trellis-Coded CPM (Continuous-Phase Modulated Signals) for Satellite-Based Mobile Communications.  

National Technical Information Service (NTIS)

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 b...

F. Abrishamkar E. Biglieri

1988-01-01

218

Incorporating guidelines for use of mobile technologies in health research and practice.  

PubMed

This commentary aims to create initial recommendations to guide researchers' decisions on the development and use of mobile technologies for public health research. We recommend that mobile technologies for public health research should be scalable and sustainable; draw on social, psychological and/or behavioral theoretical models; be able to be integrated with multiple communication devices; incorporate social network and/or geographic metrics and take a community-based participatory approach to development and implementation. All of these approaches are discussed. PMID:24713154

Young, Sean D; Holloway, Ian W; Swendeman, Dallas

2014-06-01

219

Children's Literature in the Undergraduate Course on Communication Research Methods  

ERIC Educational Resources Information Center

Objective: Students will develop positive attitudes toward communication research by linking new values and principles with the familiar values and principles contained in children's literature. Course: Communication Research Methods.

Brown, Daniel S.

2010-01-01

220

Evolution of Implicit and Explicit Communication in Mobile Robots  

NASA Astrophysics Data System (ADS)

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.

de Greeff, Joachim; Nolfi, Stefano

221

Free Space Optics Communication for Mobile Military Platforms.  

National Technical Information Service (NTIS)

Free Space Optics (FSO) is widely regarded as the next-generation high-speed wireless communication technology. FSO has demonstrated its capability to deliver data faster than any other state-of-the-art wireless communication technology. Today, terrestria...

S. S. Neo

2003-01-01

222

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

NASA Technical Reports Server (NTRS)

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.

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

1990-01-01

223

Improving the Communication of Spatial Information in Crisis Response by Combining Paper Maps and Mobile Devices  

Microsoft Academic Search

Ecient and eective communication between mobile units and the central emergency operation center is a key factor to respond successfully to the challenges of emergency management. Nowadays, the only ubiquitously available modality is a voice channel through mobile phones or radio transceivers. This makes it often very dicult to convey exact geographic locations and can lead to misconceptions with severe

Johannes Schoning; Michael Rohs; Antonio Kruger; Christoph Stasch

224

Error control for Ka-band land mobile satellite communications systems  

Microsoft Academic Search

Error control for Ka-band land mobile satellite communications systems is examined. The dominant propagation effect at Ka-band is signal shadowing caused by obstructions in the propagation path. Depending on the mobile speed, shadow events may last for many seconds and will typically result in attenuations at the receiver too severe to be addressed by raw link margin. The performance of

Jeffrey B. Schodorf

2000-01-01

225

Design of the mobile satellite communications constellations with common ground track  

Microsoft Academic Search

This paper, from the viewpoint characteristics of the mobile satellite ground track, discusses a method of designing of mobile satellite constellations with a common ground track., and also uses the method for China's area coverage design by way of computer simulation and a specialized satellite communication tool. By choosing the satellite orbit period as one fourth of the sidereal day,

He Jiafu; Wu Jiuyin; Ma Yifei; Gan Zhongmin

1999-01-01

226

Mobile Communications, Social Networks, and Urban Travel: Hypertext as a New Metaphor for Conceptualizing Spatial Interaction  

Microsoft Academic Search

The widespread use of mobile communications is leading to new practices in family life and social life, and these changes have significant implications for the study of urban travel. Because of the adoption of new modes of space-time coordination, changing time use and increasing mobility, changing use of existing urban nodes, the blurring of boundaries between home and work, the

Mei-Po Kwan

2007-01-01

227

Application of antenna arrays to mobile communications. II. Beamforming and direction-of-arrival considerations  

Microsoft Academic Search

Array processing involves manipulation of signals induced on various antenna elements. Its capabilities of steering nulls to reduce cochannel interferences and pointing independent beams toward various mobiles, as well as its ability to provide estimates of directions of radiating sources, make it attractive to a mobile communications system designer. Array processing is expected to play an important role in fulfilling

LAL C. GODARA

1997-01-01

228

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

ERIC Educational Resources Information Center

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…

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

2008-01-01

229

Research of intelligent recommendation for mobile reading  

NASA Astrophysics Data System (ADS)

Mobile reading is the trend of current publishing industry. Intelligent Recommendation system is useful and profitable for mobile reading platforms. Currently, intelligent recommendation systems mainly focus on news recommendation or production recommendation in e-commerce. In this paper, we designed and implemented an intelligent recommendation system based on slope one algorithm. Results show that our algorithm can help the users to find their interested books and thus greatly improve the income of mobile reading platform.

Li, Qu

2013-07-01

230

Dedicated short-range communication mobile device for intelligent transport systems  

US Patent & Trademark Office Database

A dedicated short-range communication mobile device for Intelligent transport systems, including: an antenna; a data transmission/reception circuit for transmitting and receiving data to and from a ground device through the antenna; a first power supply circuit for supplying power to the data transmission/reception circuit; a received electric field strength detecting unit for measuring a power level of a radio wave transmitted from the ground device; a communication area detecting unit for recognizing a communication area based on an output of the received electric field strength detecting unit; a power supply starting unit for starting the first power supply circuit based on an output of the communication area detecting unit; and a second power supply circuit for supplying power to the received electric field strength detecting unit, the communication area detecting unit and the power supply starting unit. As a result of the above configuration, the mobile device can reduce dissipation and does not complicate communication control.

2002-01-08

231

An efficient communication strategy for ad-hoc mobile networks  

Microsoft Academic Search

We investigate here the problem of establishing communica- tion in an ad-hoc mobile network, that is, we assume the extreme case of a total absense of any flxed network infrastructure (for example a case of rapid deployment of a set of mobile hosts in an unknown terrain). We propose, in such a case, that a small subset of the deployed

Ioannis Chatzigiannakis; Sotiris E. Nikoletseas; Paul G. Spirakis

2001-01-01

232

A Content Analysis of Research on Religion and Spirituality in General Communication and Health Communication Journals  

Microsoft Academic Search

Little research has been conducted within the field of communication regarding the intersection of religious faith and health communication. One step toward addressing the existing gap in health communication literature is to establish an accurate picture of the present state of affairs. The purpose of this study was to describe publication patterns in communication journals over the past 10 years

Ann Neville Miller; Simone Teel

2011-01-01

233

Minimizing the mass of a communications system for a multi-beam mobile communications satellite with elliptical beams  

NASA Astrophysics Data System (ADS)

The mass-minimizing configuration was studied for a multi-beam mobile communications satellite by using an elliptical-beam with a greater number of beams for receiving than for transmitting. Optimum transponder output power, major and minor axes size of the elliptical antenna, and the number of transmitting and receiving beams are obtained along with the lowest possible effective mass for the communications equipment. The minimum effective mass achieved is about 10 % smaller than the effective mass of communications system which use conventional multi-circular beams.

Kobayashi, Akihiko; Ishii, Kyoichi; Okamoto, Teruki; Masuda, Nobuo; Iso, Akio; Sato, Shin-Ichi

234

Mobile communication, public participation and e-governance in China: a case study of Xiamen anti-PX demonstration  

Microsoft Academic Search

China has become the biggest mobile communication carrier in the world since 2001. Advanced technologies create a communication revolution, and the individual, through the advent of mobile media, has become an active participant in this process. This study investigates the mobile phone's impact upon the developments of public participation, social inclusion and citizenship through the case study of Xiamen PX

Liu Jun; Zhao Hui

2010-01-01

235

A Mobile Robots Experimental Environment with Event-Based Wireless Communication  

PubMed Central

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.

Guinaldo, Maria; Fabregas, Ernesto; Farias, Gonzalo; Dormido-Canto, Sebastian; Chaos, Dictino; Sanchez, Jose; Dormido, Sebastian

2013-01-01

236

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

PubMed

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

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

2013-01-01

237

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

PubMed Central

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.

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

2012-01-01

238

Satellite-aided land mobile communications system implementation considerations  

NASA Technical Reports Server (NTRS)

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.

Leroy, B. E.

1982-01-01

239

International Research Network in European Political Communications  

NSDL National Science Digital Library

EurPolCom was initially established in 2000, by Professor Paul Statham, and located at the University of Leeds. In 2007, it was re-launched as a 'network' which advances research in the fields of political communications, the public sphere and social movements and is now located at the University of Bristol. On their website visitors can learn more about this organization and their various research projects. In addition, there are a number of working papers available to the public including "Constitutionalism of the European Public Sphere" and "The Politics of Immigration and Asylum Policy in Western Europe" to name only a few. After getting acquainted, visitors may want to learn more about their grants and awards available as well as upcoming events. Lastly, a set of related links is provided for those interested in a specific aspect of the site.

240

Research Priorities in Networking and Communications Research (Workshop Report)  

NSF Publications Database

Network interface architectures Network interfaces are responsible for connecting networks to hosts and other networks, and are critical to the performance and usefulness of networks. Examples of research topics in network interface architectures include; workstation I/O architectures to support high-speed network interfaces; low-latency (sub 10-microsecond) end-to-end inter-host communication; integration of architectural development of hosts, with that of local, metropolitan, and wide area ...

241

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

NASA Technical Reports Server (NTRS)

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.

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

1982-01-01

242

Recasting Communication Theory and Research: A Cybernetic Approach.  

ERIC Educational Resources Information Center

The author's main concern is to provide a research format which will supply a unitary conception of communication. The wide range of complex topics and variety of concepts embraced by communication theory and the rather disparate set of phenomena encompassed by communication research create this need for a unitary study approach capable of linking…

Hill, Gary A.

243

The application of the diversity in mobile free-space optical communication  

NASA Astrophysics Data System (ADS)

Traditional free-space optical (FSO) communications use a single transmitting antenna (laser/VCSEL/LED) and a receiving antenna (a photo-detector) for single channel communication between two nodes. In this paper we study two transmitting antenna one receiving antenna M-FSO (mobile FSO) communication system. In the process of single transmitting antenna moving, the optical beam broadens to make receive power smaller with the divergence angle larger and the power is difficult to be detected when long-distance communication. When short-distance communication, the divergence angle is so small that it makes a narrow beam which is hard to be aimed at receive aperture, even more serious when the beam is out of target caused by vibration. We take advantage of space diversity technology to reduce BER caused by atmospheric turbulence and mobile vibration. Through the multi-transmitter, the best choice of multi-divergence angle reduces BER, thus the receiver accurately recovers information.

Li, Yingchun; Zhang, Rui

2008-03-01

244

Weather Information Communication Technologies for Increased Safety and Mobility in the National Airspace System.  

National Technical Information Service (NTIS)

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 bet...

D. R. Hilderman

2006-01-01

245

Application of Space Communications to the Maritime Mobile Service.  

National Technical Information Service (NTIS)

There is growing interest in the use of satellites for maritime communications and position determination. Presentation is made of operational requirements, joint use by ships and aircraft, areas to be covered, conditions of system's operations, frequency...

C. Dorian

1971-01-01

246

Estimation of the demand for public services communications. [market research and economic analysis for a communications satellite system  

NASA Technical Reports Server (NTRS)

Market analyses and economic studies are presented to support NASA planning for a communications satellite system to provide public services in health, education, mobile communications, data transfer, and teleconferencing.

1976-01-01

247

Challenging Mobile Learning Discourse through Research: Student Perceptions of "Blackboard Mobile Learn" and "iPads"  

ERIC Educational Resources Information Center

Many university academics disagree with the rationale that we should pursue mobile learning because 21st century students are apparently demanding it. We argue that the only defensible rationale for making mobile learning part of pedagogy is because it enhances student learning. This presentation shares results from research with 135 students…

Kinash, Shelley; Brand, Jeffrey; Mathew, Trishita

2012-01-01

248

Satellite-aided land mobile communications system implementation considerations  

NASA Technical Reports Server (NTRS)

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

Leroy, B. E.

1982-01-01

249

Satellite Communications for Aeronautical Applications: Recent research and Development Results  

NASA Technical Reports Server (NTRS)

Communications systems have always been a critical element in aviation. Until recently, nearly all communications between the ground and aircraft have been based on analog voice technology. But the future of global aviation requires a more sophisticated "information infrastructure" which not only provides more and better communications, but integrates the key information functions (communications, navigation, and surveillance) into a modern, network-based infrastructure. Satellite communications will play an increasing role in providing information infrastructure solutions for aviation. Developing and adapting satellite communications technologies for aviation use is now receiving increased attention as the urgency to develop information infrastructure solutions grows. The NASA Glenn Research Center is actively involved in research and development activities for aeronautical satellite communications, with a key emphasis on air traffic management communications needs. This paper describes the recent results and status of NASA Glenn's research program.

Kerczewski, Robert J.

2001-01-01

250

Intelligent mobility research for robotic locomotion in complex terrain  

NASA Astrophysics Data System (ADS)

The objective of the Autonomous Intelligent Systems Section of Defence R&D Canada - Suffield is best described by its mission statement, which is "to augment soldiers and combat systems by developing and demonstrating practical, cost effective, autonomous intelligent systems capable of completing military missions in complex operating environments." The mobility requirement for ground-based mobile systems operating in urban settings must increase significantly if robotic technology is to augment human efforts in these roles and environments. The intelligence required for autonomous systems to operate in complex environments demands advances in many fields of robotics. This has resulted in large bodies of research in areas of perception, world representation, and navigation, but the problem of locomotion in complex terrain has largely been ignored. In order to achieve its objective, the Autonomous Intelligent Systems Section is pursuing research that explores the use of intelligent mobility algorithms designed to improve robot mobility. Intelligent mobility uses sensing, control, and learning algorithms to extract measured variables from the world, control vehicle dynamics, and learn by experience. These algorithms seek to exploit available world representations of the environment and the inherent dexterity of the robot to allow the vehicle to interact with its surroundings and produce locomotion in complex terrain. The primary focus of the paper is to present the intelligent mobility research within the framework of the research methodology, plan and direction defined at Defence R&D Canada - Suffield. It discusses the progress and future direction of intelligent mobility research and presents the research tools, topics, and plans to address this critical research gap. This research will create effective intelligence to improve the mobility of ground-based mobile systems operating in urban settings to assist the Canadian Forces in their future urban operations.

Trentini, Michael; Beckman, Blake; Digney, Bruce; Vincent, Isabelle; Ricard, Benoit

2006-06-01

251

Ion mobility spectrometry in breath research.  

PubMed

The number of publications in the field of breath analysis using different types of ion mobility spectrometers (IMS) has increased over the last few years. In this paper, the publications between 2010 and 2013 are reviewed with respect to different types of IMS such as differential mobility spectrometers, high-field asymmetric waveform ion mobility spectrometers and multi-capillary columns coupled to conventional IMS. The analytes detected by IMS and declared with significance to a specific medical question were considered further with respect to medical and analytical questions. In total, 42 different analytes were found to be detected using IMS on a high significance level and were compared to findings using other analytical methods with respect to the individual analyte. PMID:24682214

Fink, Tobias; Baumbach, Jörg I; Kreuer, Sascha

2014-06-01

252

Low delay, error resilient error control for mobile video communication  

Microsoft Academic Search

This paper proposes a low delay, error resilient video transmission scheme for mobile radio channels. Compressed video data is sensitive to channel error. Channel error can fatally degraded the reconstructed video sequence by causing intra-frame and inter-frame error propagation. Using ARQ to prevent all forms of error propagation, significantly increases the transmission delay of the video frame. We propose a

Naoto Matoba; Yasushi Kondo; Toshiaki Tanaka

1997-01-01

253

Power Control and MIMO Beamforming in CDMA Mobile Communications Systems.  

National Technical Information Service (NTIS)

This thesis concerns two interference management methods, the power control and the smart antenna. Power control balances received powers of all users so that a measure of the co-channel interference achieves a minimum. Using the beamforming in the mobile...

M. S. Elmusrati

2002-01-01

254

Mobile teleoperator research at Savannah River Laboratory  

SciTech Connect

A Robotics Technology Group was organized at Savannah River Laboratory to employ modern automation and robotics for applications at the Savannah River site. Several industrial robots have been installed in plant processes. Other robotics systems are under development in the laboratories, including mobile teleoperators for general remote tasks and emergency response operations. This paper discusses present work on a low-cost wheeled mobile vehicle, a modular light duty manipulator arm, a large gantry telerobot system, and a high technology six-legged walking robot with a teleoperated arm.

Byrd, J S

1985-01-01

255

Organizational Communication: Research and Practice. ERIC Digest.  

ERIC Educational Resources Information Center

In colleges and universities business students learn about organizational communication in order to function well in the business environment of which they will become a part. Although the organizational environment or culture is inextricably interwoven with the academic discipline of speech communication, the field of organizational communication

Aiex, Nola Kortner

256

Improving the Communication of Spatial Information in Crisis Response by Combining Paper Maps and Mobile Devices  

Microsoft Academic Search

Efficient and effective communication between mobile units and the central emergency operation center is a key factor to respond\\u000a successfully to the challenges of emergency management. Nowadays, the only ubiquitously available modality is a voice channel\\u000a through mobile phones or radio transceivers. This makes it often very difficult to convey exact geographic locations and can\\u000a lead to misconceptions with severe

Johannes Schöning; Michael Rohs; Antonio Krüger; Christoph Stasch

2008-01-01

257

A model for local\\/mobile radio communications with correct packet capture  

Microsoft Academic Search

The performance of a local\\/mobile radio communications system utilizing the slotted ALOHA multiple random access protocol is analyzed. The probability of correct packet capture is evaluated for a local\\/mobile packet radio system using ideal coherent binary phase-shift keying (BPSK) modulation. Both the near\\/far effect and the effect of Rayleigh fading on the probability of correct packet capture are taken into

R. Clark Robertson; Tri T. Ha

1992-01-01

258

[Psychophysiological indicators for children using mobile phones. Communication 2. Results of four-year monitoring].  

PubMed

This study submits the results of a four-year monitoring of a complex diagnostics of the psychophysiological indicators for 196 children aged 7 to 12 years old: 147 of them are child users of mobile communication (test group) and 49 are in the control group. We have identified the following major trends of the psychophysiological indicators for child users of mobile communication: an increased number of phonemic perception disorders, abatement of efficiency, reduced indicators for the arbitrary and semantic memory, an increased fatigue. A steady decline of the parameters from high values to bottom standards has been found. PMID:22279774

Khorseva, N I; Grigor'ev, Iu G; Gorbunova, N V

2011-01-01

259

“Race Matters” in the Journal of Applied Communication Research  

Microsoft Academic Search

Social issues have been a general stimulus for communication scholarship since the inception of the field. Over time, much of this research has evolved into what is known as applied communication research. Within this article, the authors report a critical analysis of research about a particularly significant social issue: race. In particular, they analyze articles published in The Journal of

Mark P. Orbe; Brenda J. Allen

2008-01-01

260

The Troubled Waters of Communication Research: A Position Paper.  

ERIC Educational Resources Information Center

Notes that faculty members in communication departments or schools of journalism and mass communication must navigate between the Scylla of diminishing faculty lines and the Charybdis of the turbulent waters of academic scholarship. Examines problems faced by journalism and communication researchers and places their work in a contemporary…

Leslie, Larry Z.

1998-01-01

261

Efficient Use of Narrowband Radio Channels for Mobile Digital Communications.  

National Technical Information Service (NTIS)

The project developed a wireless modem architecture that provides bandwidth efficient data communications in the 220 MHz ITS spectral allocations. The goal was to provide greater than 12 kbps transmission capacity on the 4 kHz channels (3 bps/Hz spectral ...

M. P. Fitz

1996-01-01

262

Information and Communication Technology and International Business Travel: Mobility Allies?  

Microsoft Academic Search

Like forecasts about the paperless office, technological solutions to the problem of international business travel continue to be deferred. As with the increased use of office paper, international business travel is defying predictions of its decline. There is growing evidence to suggest that business sectors which seem ideally placed to substitute information and communication technology (ICT) for travel, are actually

Paul Haynes

2010-01-01

263

Joint multipath-Doppler diversity in mobile wireless communications  

Microsoft Academic Search

We introduce a new approach for achieving diversity in spread-spectrum communications over fast-fading multipath channels. The RAKE receiver used in existing systems suffers from significant performance degradation due to the rapid channel variations encountered under fast fading. We show that the Doppler spread induced by temporal channel variations in fact provides another means for diversity that can be further exploited

Akbar M. Sayeed; Behnaam Aazhang

1999-01-01

264

Increased Capacity Using CDMA for Mobile Satellite Communication  

Microsoft Academic Search

The performance of a spread-spectrum CDMA (code-division multiple access) system in a mobile satellite environment is analyzed. Comparisons to single-channel-per-carrier FDMA systems are presented which show that the CDMA approach provides greater capacity. Results from computer simulations, laboratory tests, and field tests of a prototype modem are also presented. The tests results show excellent performance of the modem in the

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

1990-01-01

265

Carrier aggregation for LTE-advanced mobile communication systems  

Microsoft Academic Search

In order to achieve up to 1 Gb\\/s peak data rate in future IMT-Advanced mobile systems, carrier aggregation technology is introduced by the 3GPP to support very-high-data-rate transmissions over wide frequency bandwidths (e.g., up to 100 MHz) in its new LTE-Advanced standards. This article first gives a brief review of continuous and non-continuous CA techniques, followed by two data aggregation

Guangxiang Yuan; Xiang Zhang; Wenbo Wang; Yang Yang

2010-01-01

266

Control based mobile ad-hoc networks for video communications  

Microsoft Academic Search

This paper presents a feedback control scheme for transmission of video signals over mobile ad-hoc channels. The scheme is a combination of cross-layer (local) feedback and receiver feedback. The receiver feedback is based on the real time transport control protocol (RTCP), which is designed to provide an end-to-end feedback assessment of multihop transmission channels by tracking packet receptions in synchronization

Hamid Gharavi

2006-01-01

267

Knowledge Mobilization and Educational Research: Politics, Languages and Responsibilities  

ERIC Educational Resources Information Center

How can educational research have more impact? What processes of knowledge exchange are most effective for increasing the uses of research results? How can research-produced knowledge be better "mobilized" among users such as practicing educators, policy makers, and the public communities? These sorts of questions are commanding urgent attention…

Fenwick, Tara, Ed.; Farrell, Lesley, Ed.

2011-01-01

268

An adaptive array antenna for mobile satellite communications  

NASA Technical Reports Server (NTRS)

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.

Milne, Robert

1990-01-01

269

Intercepting mobile communications: the insecurity of 802.11  

Microsoft Academic Search

The 802.11 standard for wireless networks includes a Wired Equivalent Privacy (WEP) protocol, used to protect link-layer communications from eavesdropping and other attacks. We have discovered several serious security flaws in the protocol, stemming from mis-application of cryptographic primitives. The flaws lead to a number of practical attacks that demonstrate that WEP fails to achieve its security goals. In this

Nikita Borisov; Ian Goldberg; David Wagner

2001-01-01

270

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

NASA Astrophysics Data System (ADS)

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.

Görbil, Gökçe; Gelenbe, Erol

271

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

NASA Astrophysics Data System (ADS)

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.

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

272

75 FR 17434 - In the Matter of Certain Personal Data and Mobile Communications Devices and Related Software...  

Federal Register 2010, 2011, 2012, 2013

...Mobile Communications Devices and Related Software; Notice of Investigation AGENCY: U...of Cupertino, California and NeXT Software, Inc. f/k/a NeXT Computer, Inc...mobile communications devices and related software by reason of infringement of...

2010-04-06

273

AI Based Approach of Predicting the Credit Limits of Users to Middle Customer based Mobile Communication Services  

Microsoft Academic Search

Most of the developing countries even, mobile communication has become a matter of course for many people. As markets saturate, the care and retention of existing customers becomes a key element for revenue stabilization for mobile communication network operators. We present a predictive data mining model to reduce the rate of forced churn as a consequence of non-payment: estimations of

A. Pallegedara; V. S. Amaratunga; R. A. R. C. Gopura; P. D. Jayathileka

2006-01-01

274

Secure communication of medical information using mobile agents.  

PubMed

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

Nikooghadam, Morteza; Zakerolhosseini, Ali

2012-12-01

275

An efficient communication strategy for mobile agent based distributed spatial data mining application  

NASA Astrophysics Data System (ADS)

An efficient communication strategy is proposed in this paper, which aims to improve the response time and availability of mobile agent based distributed spatial data mining applications. When dealing with decomposed complex data mining tasks or On-Line Analytical Processing (OLAP), mobile agents authorized by the specified user need to coordinate and cooperate with each other by employing given communication method to fulfill the subtasks delegated to them. Agent interactive behavior, e.g. messages passing, intermediate results exchanging and final results merging, must happen after the specified path is determined by executing given routing selection algorithm. Most of algorithms exploited currently run in time that grows approximately quadratic with the size of the input nodes where mobile agents migrate between. In order to gain enhanced communication performance by reducing the execution time of the decision algorithm, we propose an approach to reduce the number of nodes involved in the computation. In practice, hosts in the system are reorganized into groups in terms of the bandwidth between adjacent nodes. Then, we find an optimal node for each group with high bandwidth and powerful computing resources, which is managed by an agent dispatched by agent home node. With that, the communication pattern can be implemented at a higher level of abstraction and contribute to improving the overall performance of mobile agent based distributed spatial data mining applications.

Han, Guodong; Wang, Jiazhen

2005-11-01

276

A frame synchronization method for adaptive array antennas in digital mobile communications  

Microsoft Academic Search

This paper proposes a frame synchronization method for an adaptive array antenna (AAA) used in digital mobile communications. The proposed scheme, which is based on the maximum likelihood estimation (MLE), calculates error signals by subtracting a training sequence convolved with an estimated channel impulse response from the AAA outputs and searches for the timing that minimizes the mean squared errors.

Kazuhiko Fukawa; Hiroshi Suzuki

2005-01-01

277

TCP\\/IP Performance Evaluations Based on Elevation Angles for Mobile Communications Employing Stratospheric Platform  

Microsoft Academic Search

This paper describes a proposed propagation estimation method and TCP\\/IP-based evaluations for mobile communications employing a stratospheric platform. To estimate a wireless channel, a realistic and detailed description of its physical environment must be accurately defined. Therefore, a building distribution model characterizing the physical environment in areas in Japan is presented. The analyses of the propagation estimation method are based

Marry Kong; Otabek Yorkinov; Shigeru Shimamoto

2009-01-01

278

The land mobile satellite communication channel-recording, statistics, and channel model  

Microsoft Academic Search

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

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

1991-01-01

279

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

Microsoft Academic Search

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

Yongli Yang; Guangxi Zhu; Desheng Wang; Lifen Wu

2007-01-01

280

User and Concept Studies as Tools in Developing Mobile Communication Services for the Elderly  

Microsoft Academic Search

The basis of this study was the ageing of the population all over the world. The study concentrated on finding out the key service needs of elderly people. The service needs from the end users’ as well as the experts’ perspective were gathered by means of various group methods such ideation sessions. Four mobile communication service concepts were created using

M. Mikkonen; S. Väyrynen

2002-01-01

281

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

ERIC Educational Resources Information Center

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…

Jones, Geraldine; Edwards, Gabriele; Reid, Alan

2009-01-01

282

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

ERIC Educational Resources Information Center

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…

Chaiprasurt, Chantorn; Esichaikul, Vatcharaporn

2013-01-01

283

Communication and processing consideration for alerting systems implemented through mobile sensor networks  

Microsoft Academic Search

At the beginning of the paper it is presented an alerting system architecture based on mobile sensor network. Then it is analyzed the current available radio communication infrastructure which can be used for implementation of alerting systems in conjunction with the alerting systems requirements. Further we shown how the digital signal processor (DSPs) are the best fit for the processing

DAN POPESCU; RADU DOBRESCU; MAXIMILIAN NICOLAE; ALEXANDRU IORDAN

2009-01-01

284

Switching Costs, Consumers' Heterogeneity and Price Discrimination in the Mobile Communications Industry  

Microsoft Academic Search

In this paper we develop a formal model that captures some basic features of competition in the mobile communications service industry. In a model of oligopolistic competition with price discrimination and switching costs, we study the role of firms’ installed base of consumers in providing the incentives to offer contracts for a new class of consumers with a lower willingness

Nicoletta Corrocher; Lorenzo Zirulia

2005-01-01

285

Twin-object platform: a generic proxy-based system for communication customization in mobile computing  

Microsoft Academic Search

Communication customization has been widely used and proved having benefits in mobile computing. However, most systems are designed for specific purposes. They may have weaknesses in compatibility and portability, and incur unnecessary overheads in certain situations. Besides, they may be not flexible as a generic system because of requiring particular software facilities or hardware devices. In the paper, we propose

Tzu-Chi Huang; Ce-Kuen Shieh; Yu-Ben Miao

2005-01-01

286

An Implanted Spherical Head Model Exposed to Electromagnetic Fields at a Mobile Communication Frequency  

Microsoft Academic Search

Can cellular phones and personal communication systems base station antennas affect the active or passive implantable medical devices adversely? Concerns over the possible harmful effects of nonionizing irradiation upon implanted medical devices have been present for many years. Key issues to address are the questions of whether mobile phones have a detrimental effect on implants, and how the interaction of

S. M. S. Reyhani; Simone A. Ludwig

2006-01-01

287

Laypeople's Health Concerns and Health Beliefs in Regard to Risk Perception of Mobile Communication  

Microsoft Academic Search

The consensus scientific view is that there is an absence of convincing scientific evidence for health risks of exposures to electromagnetic fields (EMF) at levels below those recommended in international guidelines. Nevertheless, some citizens are worried about EMF emitted by mobile communication and its consequences for health. The present study explored, by means of a mail survey, health concerns and

Marie-Eve Cousin; Michael Siegrist

2008-01-01

288

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

NASA Astrophysics Data System (ADS)

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 satellite communication systems. Therefore, the experimental DBF network with 16 radiating elements was developed for confirming a basic signal processing performance. A/D sampled data are processed by using FPGA circuit for beam forming by real-time basis. Optical Inter-Satellite Link Technology: The inter-satellite link (ISL) technology is also important, because the inter-satellite network is essential to realize the low delay network connection for multimedia services. The optical ISL simulator was developed for the study of optical modem and optical tracking mechanism. And the sensitivity of 56 photons/bit at 10-9 of error rate has been achieved by employing the Erbium doped fiber amplifier, polarizing filter and narrow band optical filter. Coude path type, the active universal joint (AUJ) type and two flat mirror type of optical antenna mechanism were developed. Satellite Network Technology: For constructing this optical ISL ring, the utilization of wavelength division multiplexing (WDM) technology is envisaged. By applying WDM technology to the optical intra-orbital ISL, logical mesh connections can be achieved by assigning the appropriate wavelength for the links among satellites. By using inclined orbit, inter-orbital ISL connection can be keep continuously. Therefore, WDM technology is also applicable to the inter-orbital ISL network. The satellite ATM network simulator was developed in order to investigate the effect of delay fluctuation caused by the satellite constellations. This simulator works as real-time basis by using commercial ATM switches and personal computers. This simulator was installed Dijkstra's algorithm to determine satellite routing path in order to minimize the end-to-end delay time from the source terminal to the destination terminal. The satellite IP network simulator has been developed in order to evaluate the congestion of the multimedia traffic. Variable Rate Modulation Technology: Considering the propagation impairments in the mobile conditions, we employ the variable rate transmission, which maintains the communication service

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

2002-01-01

289

Federal Research and Development for Satellite Communications.  

ERIC Educational Resources Information Center

This report of the Committee on Satellite Communications (COSC) reviews a number of future communication needs which could be satisfied by satellite systems, including needs in fields such as education, health care delivery, hazard warning, navigation aids, search and rescue, electronic mail delivery, time and frequency dissemination, and…

National Academy of Sciences - National Research Council, Washington, DC. Assembly of Engineering.

290

Implications of Research in Communication Education for the Black Child.  

ERIC Educational Resources Information Center

This paper discusses several aspects of the need for research in communication education for black children. Initial comments underline the need for educating teachers in communication behavior and teaching methods. The complex nature of the problem under review indicates the need for careful delineation of the problem for effective research and…

Holt, Grace S.

291

Evaluating Factor Analysis Decisions for Scale Design in Communication Research  

Microsoft Academic Search

Factor analysis techniques offer the communication researcher a set of important tools for the development and substantiation of attitude and opinion scales. Often, however, crucial factoring decisions are based on convention or misunderstanding, leading to questionable conclusions. The purpose of this article is to offer the nontechnical communication researcher a foundation for making and defending rational factoring decisions that can

John T. Morrison

2009-01-01

292

Communication in Surveys: Examining Cognitive Effects in Survey Research.  

ERIC Educational Resources Information Center

Panel studies have frequently been used by mass communication researchers. While these studies allow researchers to draw inferences about mass communication effects over time, they also tend to sensitize respondents to the issue under study. A study was undertaken to investigate panel effects by examining the survey interview as a medium of…

Salmon, Charles T.; And Others

293

A study and experiment plan for digital mobile communication via satellite  

NASA Technical Reports Server (NTRS)

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.

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

1978-01-01

294

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

NASA Technical Reports Server (NTRS)

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.

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

1995-01-01

295

Steerable L-band antenna for land mobile voice communication terminal  

NASA Astrophysics Data System (ADS)

The ESA is developing an EMS (European Mobile System) land mobile voice communication system. Two steerable prototype antennas were developed for an EMS mobile voice communication terminal. The first one is a rotating antenna consisting of two OTA (One Turn Antenna) elements. The feed network generates two separate beams slightly shifted from the boresight. The tracking is based on level difference measurements from these two beams. The mechanical rotation is accomplished by the aid of a step motor. The acquisition and tracking are controlled by a microprocessor. The second antenna is a fully electronic array consisting of 12 OTA elements locating on a circle. The compact feed network gives rise to 24 separate beams in the azimuth plane. The tracking is based on the use of these multiple beams and the performance is enhanced by direction information from a digital compass. The design and performance of both these antennas are described.

Aurinsalo, J.; Hujanen, A.; Jongejans, A.; Marttila, I.; Mutanen, R.; Pitkaenen, I.; Tallqvist, S.

1991-10-01

296

Research the mobile phone operation interfaces for vision-impairment.  

PubMed

Due to the vision-impaired users commonly having difficulty with mobile-phone function operations and adaption any manufacturer's user interface design, the goals for this research are established for evaluating how to improve for them the function operation convenience and user interfaces of either mobile phones or electronic appliances in the market currently. After applying collecting back 30 effective questionnaires from 30 vision-impairment, the comments have been concluded from this research include: (1) All mobile phone manufactures commonly ignorant of the vision-impairment difficulty with operating mobile phone user interfaces; (2) The vision-impairment preferential with audio alert signals; (3) The vision-impairment incapable of mobile-phone procurement independently unless with assistance from others; (4) Preferential with adding touch-usage interface design by the vision-impairment; in contrast with the least requirement for such functions as braille, enlarging keystroke size and diversifying-function control panel. With exploring the vision-impairment's necessary improvements and obstacles for mobile phone interface operation, this research is established with goals for offering reference possibly applied in electronic appliance design and . Hopefully, the analysis results of this research could be used as data references for designing electronic and high-tech products and promoting more usage convenience for those vision-impaired. PMID:22317456

Yao, Yen-Ting; Leung, Cherng-Yee

2012-01-01

297

The Mobile Agents Integrated Field Test: Mars Desert Research Station April 2003  

NASA Technical Reports Server (NTRS)

The Mobile Agents model-based, distributed architecture, which integrates diverse components in a system for lunar and planetary surface operations, was extensively tested in a two-week field "technology retreat" at the Mars Society s Desert Research Station (MDRS) during April 2003. More than twenty scientists and engineers from three NASA centers and two universities refined and tested the system through a series of incremental scenarios. Agent software, implemented in runtime Brahms, processed GPS, health data, and voice commands-monitoring, controlling and logging science data throughout simulated EVAs with two geologists. Predefined EVA plans, modified on the fly by voice command, enabled the Mobile Agents system to provide navigation and timing advice. Communications were maintained over five wireless nodes distributed over hills and into canyons for 5 km; data, including photographs and status was transmitted automatically to the desktop at mission control in Houston. This paper describes the system configurations, communication protocols, scenarios, and test results.

Clancey, William J.; Sierhuis, Maarten; Alena, Rick; Crawford, Sekou; Dowding, John; Graham, Jeff; Kaskiris, Charis; Tyree, Kim S.; vanHoof, Ron

2003-01-01

298

[Perspectives of mobile communication in the management of diabetics].  

PubMed

Sufficient control of blood glucose levels has been demonstrated to be associated with improved long-term outcome in patients with diabetes. Recent advances in interface technology allow transfer of measurement data to mobile devices, which enables control, multiple access, and storage of these data and virtually links patients and care-giving physicians. The possibility of alerting predefined addressee in case of measurements below or above certain limits offers some sort of security that cannot be obtained by simply penning a single value to a scratchpad. Therefore, treating physicians are able to follow the therapeutic course in an easy and finally time-independent manner. Furthermore, physical contact is not necessary, which may be favorable especially for elderly, sometimes immobile patients. PMID:21858635

Mlekusch, Wolfgang

2011-07-01

299

Future mobile satellite communication concepts at 20/30 GHz  

NASA Technical Reports Server (NTRS)

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.

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

1990-01-01

300

Design and evaluation of speech coders for mobile satellite communications  

NASA Astrophysics Data System (ADS)

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.

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

301

The triple helix model in Korean mobile communications technology innovation  

Microsoft Academic Search

The aim of this research is to analyze the success factors of Korean telecommunications industry in CDMA technology development. It is mainly based on the close triple cooperation of the government, government sponsored-research institutes and private companies that enables Korea to provide the public service of CDMA technology for the first time in the world. The rapid worldwide growth of

Sang-Young Han; Yun-Bong Auh; YeongWha Sawng

2001-01-01

302

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

NASA Astrophysics Data System (ADS)

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 presented herein. Results from flight experiments show that mobility of unmanned aircraft, following locally estimated SNIR gradients, can be used to form a locally optimized communication chain by driving the aircraft to locations that improve the end-to-end capacity of the chain over that of a range-based controller or a static deployment algorithm.

Dixon, Cory

303

Voice communication research and evaluation system  

NASA Astrophysics Data System (ADS)

The basic system is comprised of a multistation voice communication network consisting of the USAF standard aircraft intercommunication system, a standard A-19 diluter demand oxygen regulation system and an on line computer data collection and data analysis system that displays results in real time. The system is housed in a large reverberation chamber containing a programmable sound source capable of reproducing the spectrum and level of any AF operational noise environment. Standardized voice communication effectiveness test materials are used to assess the performance of any aspect of the total voice communication link, however, emphasis is usually placed upon the performance of the aircrew members. Examples of its application to voice communication problems are provided.

McKinley, R. L.

1981-06-01

304

2005 Mobility of Transfer Students in BC. Research Results  

ERIC Educational Resources Information Center

This 8-page document outlines the key findings of research conducted to assess the number and proportion of potential transfer students from Fall 2004 who subsequently registered at BC universities in 2005, as well as the mobility patterns of these students among all public post-secondary institutions in BC. The research was initiated to assist BC…

Holubeshen, Moufida; Cowin, Bob; Gaber, Devron

2006-01-01

305

Action Research Approach on Mobile Learning Design for the Underserved  

ERIC Educational Resources Information Center

This paper discusses an action research study focused on developing a mobile learning model of literacy development for underserved migrant indigenous children in Latin America. The research study incorporated a cyclical action model with four distinctive stages (Strategize, Apply, Evaluate, and Reflect) designed to guide constituencies involved…

Kim, Paul H.

2009-01-01

306

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

NASA Technical Reports Server (NTRS)

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.

Horstein, M.

1983-01-01

307

Worldwide Seamless Cellular Satellite Communications: The Global Mobile Communication by Globalstar System.  

National Technical Information Service (NTIS)

Presentation viewgraphs are presented that describe the need and technology requirements for a worldwide cellular satellite communication system. Specific services provided by such a system are outlined and the role of the service provider is described.

A. J. Navarra

1992-01-01

308

Opening communication channels with people living with HIV using mobile phone text messaging: insights from the CAMPS trial  

PubMed Central

Background Using two-way mobile phone text messages to improve adherence to antiretroviral medication enhances communication between patients and health workers. We describe the implications of participants’ responses to text messages in the Cameroon Mobile Phone SMS (CAMPS) trial. Findings This is a cross-sectional analysis of data from the intervention arm of the CAMPS trial. CAMPS was a randomized controlled trial of motivational text messaging versus usual care to improve adherence to antiretroviral medication among people living with HIV in Yaounde, Cameroon (n?=?200) over a 6 month period. Participants in the intervention arm (n?=?101) were given a contact phone number, but were not required to respond to their reminder messages. If they did, their responses were noted and reported as counts and percentages. We received 99 phone calls and 55 text messages (154 responses) from 48 participants during the study period. The median number of responses was 1 (first quartile [Q1]: 1; third quartile [Q3]: 3). Half (n?=?79, 51.1%) of them were expressions of gratitude. The rest included requests for logistical (n?=?21, 13.6%), medical (n?=?20, 12.9%) and financial (n?=?11, 7.1%) support. Conclusion Initiating two-way mobile communication opens more channels for people living with HIV to express unmet needs. Researchers, policy makers and clinicians should be ready to respond to the needs expressed by patients who respond to text messages. Trial registration Pan-African Clinical Trials Registry: PACTR201011000261458; Clinicaltrials.gov: NCT01247181

2013-01-01

309

Creating and Guiding Mobile Device Research Projects.  

National Technical Information Service (NTIS)

This paper describes a highly effective two-semester client-oriented team-based approach in which students get their first 'real' research and development experience in a carefully guided environment that fashions theory into product. Examples used descri...

C. F. Morrell G. A. Jacoby

2011-01-01

310

[Metabolic changes in cells under electromagnetic radiation of mobile communication systems].  

PubMed

Review is devoted to the analysis of biological effects of microwaves. The results of last years' researches indicated the potential risks of long-term low-level microwaves exposure for human health. The analysis of metabolic changes in living cells under the exposure of microwaves from mobile communication systems indicates that this factor is stressful for cells. Among the reproducible effects of low-level microwave radiation are overexpression of heat shock proteins, an increase of reactive oxygen species level, an increase of intracellular Ca2+, damage of DNA, inhibition of DNA reparation, and induction of apoptosis. Extracellular-signal-regulated kinases ERK and stress-related kinases p38MAPK are involved in metabolic changes. Analysis of current data suggests that the concept of exceptionally thermal mechanism of biological effects of microwaves is not correct. In turn, this raises the question of the need to revaluation of modern electromagnetic standards based on thermal effects of non-ionizing radiation on biological systems. PMID:21851043

Iakimenko, I L; Sidorik, E P; Tsybulin, A S

2011-01-01

311

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

NASA Technical Reports Server (NTRS)

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.

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

1994-01-01

312

Using Mobile Robots to Teach Articial Intelligence Research Skills  

Microsoft Academic Search

Successful Articial Intelligence researchers must be able to think creatively and critically, communicate eectively and evaluate the results of their work. Therefore, it is important in fostering quality research skills. We also wanted a project that would be fun and exciting, appeal to a wide range of students and allow for explorations in a range of AI topics. We felt

Daniel M. Gaines; Natasha Balac

313

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

NASA Astrophysics Data System (ADS)

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.

Hu, Hui; Jiang, Hong

2007-12-01

314

Aerospace Communications at the NASA Glenn Research Center  

NASA Technical Reports Server (NTRS)

The Communications Division at the NASA Glenn Research Center in Cleveland Ohio has as its charter to provide NASA and the Nation with our expertise and services in innovative communications technologies that address future missions in Aerospace Technology, Spaceflight, Space Science, Earth Science, Life Science and Exploration.

Miranda, Felix A.

2006-01-01

315

Is There Any Reason to Research Sex Differences in Communication?  

ERIC Educational Resources Information Center

Analyzes empirical findings and conceptual problems to clarify how sex differences are related to communication. Finds that conceptual reasons for the muddled picture of sex differences in communication research include reliance on stereotypes, polarization of the sexes, lack of valid reasons, and dearth of theory. (SR)

Canary, Daniel J.; Hause, Kimberley S.

1993-01-01

316

Building Collective Communication Competence in Interdisciplinary Research Teams  

ERIC Educational Resources Information Center

Using a grounded theory approach, this investigation addresses how an interdisciplinary research (IDR) team negotiates meaning and struggles to establish and sustain a sense of collective communication competence (CCC). Certain communication processes were foundational to building CCC, such as spending time together, practicing trust, discussing…

Thompson, Jessica Leigh

2009-01-01

317

Democratizing Qualitative Research: Photovoice and the Study of Human Communication  

Microsoft Academic Search

This essay discusses the possibilities of photovoice as a method to advance the study of human communication. Via a democratizing of the research process, photovoice can significantly affect the study of communication. Originally proposed by Wang and Burris (1994), photovoice traditionally has been used to study the social worlds of marginalized persons (e.g., rural, learning disabled, people without homes). Photovoice

David R. Novak

2010-01-01

318

Management Qua Communication in Rocket Research and Development  

ERIC Educational Resources Information Center

Reviews a diagnostic study conducted by a communication consultant within the George C Marshall Space Flight Center during the research and development of the Saturn V or "Moon Rocket". Participant observation and in-depth interview methodology yields information on organizational communication and systematic problems within a complex network. (MH)

Tompkins, Phillip K.

1977-01-01

319

Research on subjective symptoms and mobile telephony  

Microsoft Academic Search

In summary, the published laboratory research, to date, on electromagnetic hypersensitivity and subjective symptoms from exposures to cell-phone RF fields are very limited. One study suffered from a single-blind design, and the exposure conditions were not randomized. The other was a carefully executed, double-blind study with randomized exposures. The statistical strength was weakened by a small number of subjects in

James C. Lin

2005-01-01

320

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

NASA Technical Reports Server (NTRS)

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.

1989-01-01

321

The Status of Research on Women and Communication.  

ERIC Educational Resources Information Center

Surveys and summarizes the research published in speech communication journals on (1) historical treatments of women (2) sex differences; (3) images of women in the media; (4) education and pedagogy; and (5) surveys and integrative works. (PD)

Foss, Karen A.; Foss, Sonja K.

1983-01-01

322

The communication investigator: Teaching research methods to undergraduates  

Microsoft Academic Search

This essay explores the basic communication research course for undergraduates. Discussed are several key notions for making this course valuable to the undergraduate: the attitude of the instructor, the attitude of the students, course requirements and activities, and evaluation techniques.

Don W. Stacks; Mark Hickson III

1991-01-01

323

Audience Research for Improving Family Planning Communication Programs.  

National Technical Information Service (NTIS)

The information-education-communication (IEC) approach to family planning (FP) systematically researches and designs specific mass media messages for targeted subgroups of the population. This manual, part of a 3-part series, describes how to carry out au...

J. T. Bertrand

1980-01-01

324

An Energy Efficient Communication Protocol Based on Data Equilibrium in Mobile Wireless Sensor Network  

Microsoft Academic Search

This paper considers large-scale dense wireless sensor networks with path-constrained mobile sink. From the viewpoints of\\u000a improving data equilibrium and energy-saving, we propose an enhanced energy efficient communication protocol in which a partition\\u000a algorithm of overlapping time based on data equilibrium is designed to minimize the data variance and disequilibrium from\\u000a each node. We present a data equilibrium information diffusion

Shuai Gao; Yanchao Niu; Hongwei Huo; Hongke Zhang

2007-01-01

325

Cascaded CCI cancellation and error-correcting codes for DS-SS CDMA mobile communication system  

Microsoft Academic Search

This paper investigates the robustness of the conventional cascaded combination of co-channel interference cancellation (CCI) and the decoding of error-correcting techniques for a DS-SS CDMA mobile communication system. The system is evaluated under extreme interference conditions where the receiver is subjected to intersymbol interference (ISI), multi-access interference (MAI), and co-code CCI (CCCCI) generated within the mother cell and from the

K. M. Shaheen; Someshwar C. Gupta

1995-01-01

326

Reduced complexity comb-filters for decimation and interpolation in mobile communications terminals  

Microsoft Academic Search

In mobile communications systems complexity and efficiency are issues of paramount importance. Therefore when implementing integer factor sample-rate conversion, comb-filters-especially cascaded-integrator-comb (CIC) filters-are a good choice of realizing linear-phase filters with low complexity. However, neither the direct implementation of comb-filters as transversal filters nor their implementation as CIC-filters are minimal realizations. Since both, decimators and interpolators are time-variant systems, the

Tim Hentschel; Gerhard Fettweis

1999-01-01

327

A 60 GHz Radio-Over-Fiber Network Architecture for Seamless Communication With High Mobility  

Microsoft Academic Search

We demonstrate a 60 GHz broadband picocellular Radio-over-Fiber network architecture that enables seamless connectivity for highly mobile end-users. Its seamless communication capabilities arise by the supported handover scheme that relies on a novel Moving Extended Cell (MEC) concept. MEC exploits user-centric virtual groups of adjacent cells that transmit the same data content to the user and utilizes a switch mechanism

Nikos Pleros; Konstantinos Vyrsokinos; Kostas Tsagkaris; Nikolaos D. Tselikas

2009-01-01

328

DSD (Double Soft Decision) Concatenated FEC Scheme in Mobile Satellite Communication Systems  

Microsoft Academic Search

In order to realize a higher-code-gain forward error correction scheme in mobile satellite communication systems, a novel concatenated coding scheme employing soft decision decoding for not only inner codes but also outer codes (double soft decision, or DSD, concatenated forward error correction scheme) is proposed. Soft-decision outer decoding can improve the bit error probability of inner decoded data. In this

Shunji Honda; Shuji Kubota; Shuzo Kato

1992-01-01

329

Performance of shorted microstrip patch antennas for mobile communications handsets at 1800 MHz  

Microsoft Academic Search

We have investigated the application of two different types of novel shorted-patch antennas for mobile communications handsets at 1800 MHz. A single shorted-patch and a stacked shorted-patch antenna offering improved bandwidth are compared with data for a ?\\/4 monopole. The finite-difference time-domain (FDTD) technique was used to calculate antenna characteristics such as impedance and radiation patterns for two cases: on

Jack T. Rowley; Rod B. Waterhouse

1999-01-01

330

Novel array antenna for mobile and satellite communications with an omnidirectional radiation pattern  

NASA Astrophysics Data System (ADS)

A novel array antenna is proposed for obtaining omnidirectional radiation pattern and is suitable for satellite and mobile communication applications. The method is based on application of the Bessel function to derive a new family of array current distribution to achieve omnidirectional pattern. The array provides a microstrip implementation of an omnidirectional antenna that is simple to design and inexpensive to fabricate. Simulated results for the rectangular microstrip patch array validate the present design technique.

Singh, Ranjit

1998-07-01

331

Mobile Networked Text Communication: The case of SMS and its Influence on Social Interaction  

Microsoft Academic Search

Abstract This chapter introduces a qualitative study of the use of mobile text messaging (SMS) and reflects on how,SMS influences social interaction. It describes how,this new communication,technology is used to maintain,social relations and how,it generally assists users in their everyday activities. Three issues are highlighted: how,users use SMS to overcome shyness, how they use it for micro-grooming and how users

Louise Barkhuus

332

Overview of communications programs  

NASA Technical Reports Server (NTRS)

The objective of the communications program is to advance critical areas of enabling and enhancing communication technologies that support commercial needs, science, and exploration missions for the 1990's and beyond. The technology program consists of research and technology development in the following areas: RF technology; digital technology; optical communications; mobile communications; and systems integration, test, and evaluation.

Depaula, Ramon P.

1991-01-01

333

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

NASA Astrophysics Data System (ADS)

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.

Hayes, Edward J.; Keelty, J. Malcolm

1991-09-01

334

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

NASA Technical Reports Server (NTRS)

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.

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

1980-01-01

335

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

NASA Technical Reports Server (NTRS)

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.

Hayes, Edward J.; Keelty, J. Malcolm

1991-01-01

336

Research Challenges and Opportunities in Mobile Applications [DSP Education  

Microsoft Academic Search

tions, especially focusing on educational aspects and research problems, pointing out issues and opportunities for students in this area. Our goal is to explore challenges, possibilities, and approaches for enabling speech processing, as well as convenient and effective speech and multimodal user interfaces for mobile environments.

Dilek Hakkani-Tur; Gokhan Tur; Larry Heck

2011-01-01

337

Student Mobility Research: Next Steps. Engage. Fall/Winter 2009  

ERIC Educational Resources Information Center

This "Engage" newsletter features articles on student mobility research, supporting the BC Transfer System and inter-provincial initiatives. It announces the publication of five reports profiling students who transferred to British Columbia universities in the period 2003-04 to 2007-08. These reports provide detailed demographic and performance…

British Columbia Council on Admissions and Transfer, 2009

2009-01-01

338

Augmented Learning: Research and Design of Mobile Educational Games  

ERIC Educational Resources Information Center

New technology has brought with it new tools for learning, and research has shown that the educational potential of video games resonates with scholars, teachers, and students alike. In "Augmented Learning", Eric Klopfer describes the largely untapped potential of mobile learning games--games played on such handheld devices as cell phones, Game…

Klopfer, Eric

2008-01-01

339

Review of Computer Mediated Communication Research for Education  

ERIC Educational Resources Information Center

This research review examines recent developments in computer-mediated communication (CMC) research for educational applications. The review draws on 170 recent research articles selected from 78 journals representing a wide range of disciplines. The review focuses on peer-reviewed empirical studies, but is open to a variety of methodologies. The…

Luppicini, Rocci

2007-01-01

340

Communication between Consumers and Producers of Student Affairs Research.  

ERIC Educational Resources Information Center

To facilitate communication between researchers and research users, 268 American College Personnel Association members nominated topics in need of further research. Participants identified staff burnout, counselor effectiveness, faculty advising, older/nontraditional students, student recruitment/retention, and goals/motivations of contemporary…

Caple, Richard B.; Voss, Colleen Hester

1983-01-01

341

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

NASA Astrophysics Data System (ADS)

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).

Kollár, Martin

2012-05-01

342

48 CFR 6.302-3 - Industrial mobilization; engineering, developmental, or research capability; or expert services.  

Code of Federal Regulations, 2013 CFR

... false Industrial mobilization; engineering, developmental, or research capability...302-3 Industrial mobilization; engineering, developmental, or research capability...To establish or maintain an essential engineering, research, or development...

2013-10-01

343

How scientists use social media to communicate their research  

PubMed Central

Millions of people all over the world are constantly sharing an extremely wide range of fascinating, quirky, funny, irrelevant and important content all at once. Even scientists are no strangers to this trend. Social media has enabled them to communicate their research quickly and efficiently throughout each corner of the world. But which social media platforms are they using to communicate this research and how are they using them? One thing is clear: the range of social media platforms that scientists are using is relatively vast and dependent on discipline and sentiment. While the future of social media is unknown, a combination of educated speculation and persuasive fact points to the industry's continual growth and influence. Thus, is that not only are scientists utilizing social media to communicate their research, they must. The ability to communicate to the masses via social media is critical to the distribution of scientific information amongst professionals in the field and to the general population.

2011-01-01

344

How scientists use social media to communicate their research.  

PubMed

Millions of people all over the world are constantly sharing an extremely wide range of fascinating, quirky, funny, irrelevant and important content all at once. Even scientists are no strangers to this trend. Social media has enabled them to communicate their research quickly and efficiently throughout each corner of the world. But which social media platforms are they using to communicate this research and how are they using them? One thing is clear: the range of social media platforms that scientists are using is relatively vast and dependent on discipline and sentiment. While the future of social media is unknown, a combination of educated speculation and persuasive fact points to the industry's continual growth and influence. Thus, is that not only are scientists utilizing social media to communicate their research, they must. The ability to communicate to the masses via social media is critical to the distribution of scientific information amongst professionals in the field and to the general population. PMID:22085450

Van Eperen, Laura; Marincola, Francesco M

2011-01-01

345

Operations to Research: Communication of Lessons Learned  

NASA Technical Reports Server (NTRS)

This presentation explores ways to build upon previous spaceflight experience and communicate this knowledge to prepare for future exploration. An operational approach is highlighted, focusing on selection and retention standards (disease screening and obtaining medical histories); pre-, in-, and post-flight monitoring (establishing degrees of bone loss, skeletal muscle loss, cardiovascular deconditioning, medical conditions, etc.); prevention, mitigation, or treatment (in-flight countermeasures); and, reconditioning, recovery, and reassignment (post-flight training regimen, return to pre-flight baseline and flight assignment). Experiences and lessons learned from the Apollo, Skylab, Shuttle, Shuttle-Mir, International Space Station, and Orion missions are outlined.

Fogarty, Jennifer

2009-01-01

346

Customer Relationship Management on Internet and Mobile Channels: An Analytical Framework and Research Directions  

Microsoft Academic Search

The Internet has served as an effective channel for companies to build and manage relationships with customers. The mobile channel, emerging from the convergence of wireless communications and the mobile Web, promises to deliver additional support to meet consumer needs. This chapter examines features of customer relationship management (CRM) as implemented on the Internet (eCRM) and the mobile channel (mCRM)

Susy S. Chan

347

Research Directions in Family Communication: Proceedings of the Family Communication Research Conference (Evanston, Illinois, September 6-8, 1984).  

ERIC Educational Resources Information Center

In a conference focusing on issues in research methods, family theory, and family therapy as they relate to family communication and on future research needs, this document consists of papers presented by the 12 participants. Specific titles and speakers were as follows: "Kinship Relationships," by Mary Anne Fitzpatrick; "Research Potentials in…

Yerby, Janet, Ed.

348

[Changes in the parameters of the simple auditory-motor response in children users of mobile communication: longitudinal study].  

PubMed

The study presents the findings of longitudinal observations of the changes in the parameters of simple auditory-motor response in children-users of mobile communication. The obtained results indicate the multivariability of possible effects of radiation from mobile phones on the auditory system of children. PMID:22891552

Khorseva, N I; Grigor'ev, Iu G; Gorbunova, N V

2012-01-01

349

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

ERIC Educational Resources Information Center

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…

Campbell, Scott W.; Kwak, Nojin

2011-01-01

350

Communication and Political Mobilization: Digital Media and the Organization of Anti-Iraq War Demonstrations in the U.S  

Microsoft Academic Search

The speed and scale of mobilization in many contemporary protest events may reflect a transformation of movement organizations toward looser ties with members, enabling broader mobilization through the mechanism of dense individual-level political networks. This analysis explores the dynamics of this communication process in the case of U.S. protests against the Iraq war in 2003. We hypothesize that individual activists

W. Lance Bennett; Christian Breunig; Terri Givens

2008-01-01

351

Handoff with DSP Support: Enabling Seamless Voice Communications across Heterogeneous Telephony Systems on Dual-Mode Mobile Devices  

Microsoft Academic Search

Many mobile handsets manufactured today are equipped with wireless data modules that can provide users with the alternative to access Internet telephony service for voice communications. Due to the limited coverage area of wireless data service, however, a call established through VoIP service may need to be transferred transparently to mobile telephony service, and vice versa, for maintaining voice call

Hung-yun Hsieh; Chung-wei Li; Hsiao-pu Lin

2009-01-01

352

Challenges and future directions for tailored communication research.  

PubMed

As informatics technology advances, a growing number of research trials on tailored communications provide an accumulation of promising evidence to support their efficacy. These trials also reveal gaps and opportunities for future research. The scope and boundaries of tailoring must be redefined in terms of both new technology and the trade-offs between complexity, demand burden on participants, and the minimal information required for effective and efficient tailoring. Basic and methods research is needed to broaden theory, develop a common language, standardize measures, and isolate the key mediating mechanisms that facilitate tailored communications. Applied research must consider more rigorous research designs for efficacy trials and conduct more effectiveness trials to investigate the mechanisms of technology transfer to enhance large-scale diffusion of tailored communications. The role of contextual variables needs to be examined, as well as their interaction with different population groups, and also the channels, modes, and methods of tailored message delivery. Research is also needed on the feasibility of tailoring across clusters of multiple risk factors to identify the commonalities, differences, and interrelations among diverse behaviors. The potential cost-effectiveness of tailored communications must also be examined. No matter how efficacious, tailored communications delivered to large populations (i.e. mass-customization) will not make a public health impact unless proven to be practical and cost-efficient. PMID:10721436

Abrams, D B; Mills, S; Bulger, D

1999-01-01

353

ICSW 2 AN : An Inter-vehicle Communication System Using Mobile Access Point over Wireless Wide Area Networks  

Microsoft Academic Search

\\u000a This paper presents a prototype of inter-vehicle communication system using mobile access point that internetworks wired or\\u000a wireless LAN and wireless WAN anywhere. Implemented mobile access point can be equipped with various wireless WAN interfaces\\u000a such as WCDMA and HSDPA. Mobile access point in the IP mechanism has to process connection setup procedure to one wireless\\u000a WAN. To show the

Tae-Young Byun

2010-01-01

354

Communications, Signal Processing, and Telemetering Research Program Review  

NASA Technical Reports Server (NTRS)

A Communications, Signal Processing, and Telemetering Research Program Review was held on February 23, 1999. Research conducted under the grant was presented and reviewed, for progress, and for possible technology transfers. The research reviewed was in the following areas: (1) Bandwidth-efficient Modulation and nonlinear equalization; (2) Investigation of an architecture for parallel signal processing applicable to communications problems; (3)Coded partial response over satellites; (4) synchronization at Low SNR; (5) Serial concatenated convolutional codes and some implementation issues on high rate turbo codes; (6) Flight experiments; (7) Real time doppler tracking; (8) Space protocol testing; (9) Lightweight optical communications without carrying a laser in space. The presentations are given by the graduate students who performed the research.

1999-01-01

355

The Growth of Communication Research in Latin America.  

ERIC Educational Resources Information Center

This paper analyzes the origins, growth, and present state of communication research in Latin America. Based on empirical data, the paper identifies: (1) the factors that determined the kinds of studies that emerged in the region; (2) the major research topics; (3) the most influential scholars; and (4) the main currents of theoretical influence…

Gomez-Palacio, Carlos; Jara, J. Ruben

356

Mass Communication Research Trends from 1980 to 1999.  

ERIC Educational Resources Information Center

Uses thematic meta-analysis to examine study method, medium and area of focus, theoretical approach, funding source, and time period covered in research articles published in 10 major mass communications journals during the 1980 to 1999 period. Finds that qualitative research methods continued to be much less common than quantitative methods…

Kamhawi, Rasha; Weaver, David

2003-01-01

357

The Historical Origins of Mass Communication Research in Our Field.  

ERIC Educational Resources Information Center

The seeds of mass communication research in broadcasting were extracurricular, not academic, inspired by experimental campus radio stations. Prior to the mid-1930s, radio research was scarce. Until World War II, radio speech was the most important topic, followed by articles on how to use radio for improving instruction. There are three…

Becker, Samuel L.

358

From Research to Policy: Roma Participation through Communicative Organization  

ERIC Educational Resources Information Center

For centuries, Roma people's social exclusion has been reinforced through research that has legitimized stereotypes rather than helping to overcome them. This has led Roma people to refuse to participate in the kind of research that has contributed to discrimination against them. We describe how the critical communicative methodology, used in the…

Munte, Ariadna; Serradell, Olga; Sorde, Teresa

2011-01-01

359

Doctoral Program in Audio-Visual Communication Research. Final Report.  

ERIC Educational Resources Information Center

Program objectives may be summarized as follows: (1) to provide an opportunity for outstanding students to become trained in research through participation in a doctoral program having a special emphasis on audiovisual communication; (2) to produce persons trained in the research skills that are essential for the development, implementation, and…

Jwaideh, Alice R.

360

A Survey of Context-Aware Mobile Computing Research  

Microsoft Academic Search

Context-aware computing is a mobile computing paradigm in which applications can discover and take advantage of contextual information (such as user location, time of day, nearby people and devices, and user activity). Since it was proposed about a decade ago, many researchers have studied this topic and built several context-aware applications to demonstrate the usefulness of this new technology. Context-aware

Guanling Chen; David Kotz

2000-01-01

361

48 CFR 206.302-3 - Industrial mobilization, engineering, developmental, or research capability, or expert services.  

Code of Federal Regulations, 2013 CFR

...2013-10-01 2013-10-01 false Industrial mobilization, engineering, developmental, or research capability, or expert services...Open Competition 206.302-3 Industrial mobilization, engineering, developmental, or research capability, or expert...

2013-10-01

362

48 CFR 206.302-3 - Industrial mobilization; or engineering, development, or research capability.  

Code of Federal Regulations, 2010 CFR

...2010-10-01 2010-10-01 false Industrial mobilization; or engineering, development, or research capability...and Open Competition 206.302-3 Industrial mobilization; or engineering, development, or research...

2010-10-01

363

48 CFR 206.302-3 - Industrial mobilization; or engineering, development, or research capability.  

Code of Federal Regulations, 2010 CFR

...2009-10-01 2009-10-01 false Industrial mobilization; or engineering, development, or research capability...and Open Competition 206.302-3 Industrial mobilization; or engineering, development, or research...

2009-10-01

364

Remote monitoring system research and implementation based on wireless communication  

NASA Astrophysics Data System (ADS)

With rapid development of automatic control and network techniques, network-based remote monitoring is becoming an investigating hotspot in the elevator industry. At the same time as the development of wireless communication technology, remote wireless monitoring technology is applied more and more widely in recent years. A variety of wireless detection equipment is entering various industrial enterprises, and has been widely used. At present, there are many defects of the traditional monitoring system, such as poor real-time, low reliability, low intelligence. Based on the analysis of the difficulties to monitor the mobile terminal, this paper firstly analyzes the GSM/GPRS technology, and then discusses a design of the remote monitoring system based on wireless communication. The architecture of the monitoring center is introduced in detail. It is characterized by user-friendly, easy operate, good real-time and easy to extend.

Fu, Weizhi; Meng, Xiaofeng

2013-03-01

365

Virtual research environments in scholarly work and communications  

Microsoft Academic Search

Purpose – The purpose of this paper is to investigate the implications of the emergence of virtual research environments (VREs) and related e-research tools for scholarly work and communications processes. Design\\/methodology\\/approach – The concepts of VREs and of e-research more generally are introduced and relevant literature is reviewed. On this basis, the authors discuss the developing role they play in

Alexander Voss; Rob Procter

2009-01-01

366

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

NASA Technical Reports Server (NTRS)

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.

Paul, Lori (editor)

1991-01-01

367

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

NASA Technical Reports Server (NTRS)

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.

Gersho, Allen; Jedrey, Thomas C.

1990-01-01

368

Content Analysis as a Foundation for Programmatic Research in Communication  

PubMed Central

Previous arguments that content analyses provide the descriptive foundation for media effects research (McLeod & Reeves, 1980) are extended to include that content analyses can provide a sound and useful foundation for programmatic research by individual communication scientists. I discuss examples from my own work and from that of colleagues in communication and related disciplines. Use of messages sampled and coded in a content analysis in combination with survey data sets or as stimuli in experiments are highlighted. The particular potential for employing larger numbers of randomly sampled messages in experimental designs, and, with use of appropriate statistical methods, being able to generalize to populations of messages, is described.

Slater, Michael D.

2013-01-01

369

Autonomous Mobile Platform for Research in Cooperative Robotics  

NASA Technical Reports Server (NTRS)

This paper describes the design and development of a platform for research in cooperative mobile robotics. The structure and mechanics of the vehicles are based on R/C cars. The vehicle is rendered mobile by a DC motor and servo motor. The perception of the robot's environment is achieved using IR sensors and a central vision system. A laptop computer processes images from a CCD camera located above the testing area to determine the position of objects in sight. This information is sent to each robot via RF modem. Each robot is operated by a Motorola 68HC11E micro-controller, and all actions of the robots are realized through the connections of IR sensors, modem, and motors. The intelligent behavior of each robot is based on a hierarchical fuzzy-rule based approach.

Daemi, Ali; Pena, Edward; Ferguson, Paul

1998-01-01

370

Research Approaches to Mobile Use in the Developing World: A Review of the Literature  

Microsoft Academic Search

This paper reviews roughly 200 recent studies of mobile (cellular) phone use in the developing world, and identifies major concentrations of research. It categorizes studies along two dimensions. One dimension distinguishes studies of the determinants of mobile adoption from those that assess the impacts of mobile use, and from those focused on the interrelationships between mobile technologies and users. A

Jonathan Donner

2008-01-01

371

Research of mobile learning system based on cloud computing  

Microsoft Academic Search

Mobile learning is one of the most important e-Learning models, with the development of technology, cloud computing provides a new idea for mobile learning. After analyzing mobile learning and the various advantages it got from the cloud computing, the paper introduces a cloud-computing-based mobile learning system model, in order to promote the development of mobile learning.

Shaoyong Chen; Min Lin; Huanming Zhang

2011-01-01

372

Efficient QoS provisioning for adaptive multimedia in mobile communication networks by reinforcement learning  

NASA Astrophysics Data System (ADS)

The scarcity and large fluctuations of link bandwidth in wireless networks have motivated the development of adaptive multimedia services in mobile communication networks, where it is possible to increase or decrease the bandwidth of individual ongoing flows. This paper studies the issues of quality of service (QoS) provisioning in such systems. In particular, call admission control and bandwidth adaptation are formulated as a constrained Markov decision problem. The rapid growth in the number of states and the difficulty in estimating state transition probabilities in practical systems make it very difficult to employ classical methods to find the optimal policy. We present a novel approach that uses a form of reinforcement learning known as Q-learning to solve QoS provisioning for wireless adaptive multimedia. Q-learning does not require the explicit state transition model to solve the Markov decision problem; therefore more general and realistic assumptions can be applied to the underlying system model for this approach than in previous schemes. Moreover, the proposed scheme can efficiently handle the large state space and action set of the wireless adaptive multimedia QoS provisioning problem. Handoff dropping probability and average allocated bandwidth are considered as QoS constraints in our model and can be guaranteed simultaneously. Simulation results demonstrate the effectiveness of the proposed scheme in adaptive multimedia mobile communication networks.

Yu, Fei; Wong, Vincent W. S.; Leung, Victor C.

2003-12-01

373

A New Approach to Business-Communication Education: Integrating Business Research Methods and Communication Skills  

Microsoft Academic Search

This article describes an innovative method of teaching business communica tion. This method, which involves integrating business research methods and communication skills, has been employed and favorably received at the MBA level, especially by managers of technical and scientific personnel and by stu dents who anticipate careers in managing such personnel. This article offers a theoretical justification for such an

Alan Neff

1990-01-01

374

Content Analysis as a Best Practice in Technical Communication Research  

ERIC Educational Resources Information Center

Content analysis is a powerful empirical method for analyzing text, a method that technical communicators can use on the job and in their research. Content analysis can expose hidden connections among concepts, reveal relationships among ideas that initially seem unconnected, and inform the decision-making processes associated with many technical…

Thayer, Alexander; Evans, Mary; McBride, Alicia; Queen, Matt; Spyridakis, Jan

2007-01-01

375

Communicating bioastronautics research to students, families and the nation  

Microsoft Academic Search

The National Space Biomedical Research Institute (NSBRI) is supporting the National Aeronautics and Space Administration's (NASA) education mission through a comprehensive Education and Public Outreach Program (EPOP) that communicates the excitement and significance of space biology to schools, families, and lay audiences. The EPOP is comprised of eight academic institutions: Baylor College of Medicine, Massachusetts Institute of Technology, Morehouse School

Marlene Y. MacLeish; Nancy P. Moreno; William A. Thomson; Dava J. Newman; Patrick J. Gannon; Roland B. Smith; Jon J. Denton; Robert K. James; Craig Wilson; Marguerite Sognier; Deborah L. Illman

2005-01-01

376

Testing Equivalence in Communication Research: Theory and Application  

Microsoft Academic Search

Although equivalence testing is preferred when a researcher's goal is to support the null hypothesis (i.e., no substantial effect), equivalence tests are virtually unknown and unused in the communication field. This article provides the rationale for and theoretical background of equivalence testing and offers examples of equivalence tests for the independent and dependent groups t-test and tests of association using

René Weber; Lucy Popova

2012-01-01

377

Changing Models for Researching Pedagogy with Information and Communications Technologies  

ERIC Educational Resources Information Center

This paper examines changing models of pedagogy by drawing on recent research with teachers and their students as well as theoretical developments. In relation to a participatory view of learning, the paper reviews existing pedagogical models that take little account of the use of information and communications technologies as well as those that…

Webb, M.

2013-01-01

378

The Vienna LTE simulators - Enabling reproducibility in wireless communications research  

Microsoft Academic Search

In this article, we introduce MATLAB-based link and system level simulation environments for UMTS Long-Term Evolution (LTE).\\u000a The source codes of both simulators are available under an academic non-commercial use license, allowing researchers full\\u000a access to standard-compliant simulation environments. Owing to the open source availability, the simulators enable reproducible\\u000a research in wireless communications and comparison of novel algorithms. In this

Christian Mehlführer; Josep Colom Colom Ikuno; Michal Šimko; Stefan Schwarz; Martin Wrulich; Markus Rupp

2011-01-01

379

Small-Scale Design Experiments as Working Space for Larger Mobile Communication Challenges  

ERIC Educational Resources Information Center

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…

Lowe, Sarah; Stuedahl, Dagny

2014-01-01

380

Performance of turbo and trellis coded OFDM for LEO satellite channels in global mobile communications  

Microsoft Academic Search

Orthogonal frequency division multiplexing (OFDM) is a robust transmission technique in a Raleigh fading and Rician fading environments. The growing interest in OFDM research motivated us to propose OFDM for satellite communications. In this paper, trellis coded modulation (TCM) and turbo coding are considered with OFDM for a Rician fading channel according to the specifications given by the Iridium system.

W. A. C. Fernando; R. M. A. P. Rajatheva

1998-01-01

381

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

NASA Astrophysics Data System (ADS)

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.

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

2007-11-01

382

Research on phone contacts online status based on mobile cloud computing  

NASA Astrophysics Data System (ADS)

Because the limited ability of storage space, CPU processing on mobile phone, it is difficult to realize complex applications on mobile phones, but along with the development of cloud computing, we can place the computing and storage in the clouds, provide users with rich cloud services, helping users complete various function through the browser has become the trend for future mobile communication. This article is taking the mobile phone contacts online status as an example to analysis the development and application of mobile cloud computing.

Wang, Wen-jinga; Ge, Weib

2013-03-01

383

NASA satellite communications application research. Phase 2: Efficient high power, solid state amplifier for EFH communications  

NASA Technical Reports Server (NTRS)

The final report describes the work performed from 9 Jun. 1992 to 31 Jul. 1993 on the NASA Satellite Communications Application Research (SCAR) Phase 2 program, Efficient High Power, Solid State Amplifier for EHF Communications. The purpose of the program was to demonstrate the feasibility of high-efficiency, high-power, EHF solid state amplifiers that are smaller, lighter, more efficient, and less costly than existing traveling wave tube (TWT) amplifiers by combining the output power from up to several hundred solid state amplifiers using a unique orthomode spatial power combiner (OSPC).

Benet, James

1993-01-01

384

Data transferring technique for mobile robot controller via mobile technology  

Microsoft Academic Search

Wireless communication technology is one of the most popular and important communications at this moment. The field of robotics includes various sectors such as factory sector, manufacturing and security. These papers describe research and investigation on mobile technologies usage such as 3G for mobile robot controller. Prototype development to be done to determine the capability of technology used to control

Saliyah Kahar; Riza Sulaiman; Anton Satria Prabuwono; Mohd Fahmi Mohamad Amran; Suziyanti Marjudi

2011-01-01

385

Combined Effect of Random Transmit Power Control and Inter-Path Interference Cancellation on DS-CDMA Packet Mobile Communications  

NASA Astrophysics Data System (ADS)

In mobile communication systems, high speed packet data services are demanded. In the high speed data transmission, throughput degrades severely due to severe inter-path interference (IPI). Recently, we proposed a random transmit power control (TPC) to increase the uplink throughput of DS-CDMA packet mobile communications. In this paper, we apply IPI cancellation in addition to the random TPC. We derive the numerical expression of the received signal-to-interference plus noise power ratio (SINR) and introduce IPI cancellation factor. We also derive the numerical expression of system throughput when IPI is cancelled ideally to compare with the Monte Carlo numerically evaluated system throughput. Then we evaluate, by Monte-Carlo numerical computation method, the combined effect of random TPC and IPI cancellation on the uplink throughput of DS-CDMA packet mobile communications.

Kudoh, Eisuke; Ito, Haruki; Wang, Zhisen; Adachi, Fumiyuki

386

Technologies for Learning? An Actor-Network Theory Critique of "Affordances" in Research on Mobile Learning  

ERIC Educational Resources Information Center

How is the link between learner and technology made in mobile learning? What is the value of the concept of "affordances"? And how does research articulating this concept act to position mobile devices as "technologies for learning"? This literature review used both unstructured and structured search samples of published research on mobile

Wright, Steve; Parchoma, Gale

2011-01-01

387

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

NASA Technical Reports Server (NTRS)

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.

1983-01-01

388

Technical characteristics of the OmniTRACS: The first operation mobile Ku-band satellite communications system  

NASA Technical Reports Server (NTRS)

The techinical characteristics of the OmniTRACS system are described. The system is the first operational mobile Ku-band satellite communications system and provides two-way message and position determination service to mobile terminals using existing Ku-band satellites. Interference to and from the system is minimized by the use of special spread-spectrum techniques, together with low power and low data rate transmissions.

Antonio, Franklin P.; Gilhousen, Klein S.; Jacobs, Irwin M.; Weaver, Linday A., Jr.

1988-01-01

389

[Researcher, physician, patient connection in information, communication, and relationship].  

PubMed

The change from the sociology of medicine to the sociology of health comes about in a post-modern social context characterized by a complex and ambiguous situation. This is particularly true in the case of maternity where communication between people of different knowledge is fundamental: the researcher, doctor and female patient tend to lean towards an auto-referential relationship based on an informative communication method (as emerged from a survey on how women patients received information in the cities of Bologna and Urbino). Adopting a relational type communication based on listening, the three subjects can create a common system which, thanks also to the support of modern technology, can help to easily overcome the difficulties encountered. PMID:10645665

Mazzoli, G

1999-01-01

390

The Shared Mobile Atmospheric Research and Teaching Radar: A Collaboration to Enhance Research and Teaching.  

NASA Astrophysics Data System (ADS)

A group of scientists from three universities across two different states and from one federal research laboratory joined together to build and deploy two mobile C-band Doppler weather radars to enhance research and promote meteorological education. This 5-yr project led to the development of the Shared Mobile Atmospheric Research and Teaching (SMART) radar coalition that built the first mobile C-band Doppler weather radar in the United States and also successfully deployed the first mobile C-band dual-Doppler network in a landfalling hurricane. This accomplishment marked the beginning of an era in which high temporal and spatial resolution precipitation and dual-Doppler wind data over mesoscale (100 km) regions can be acquired from mobile ground-based platforms during extreme heavy rain and high-wind events.In this paper, we discuss the rationale for building the mobile observing systems, highlight some of the challenges that were encountered in creating a unique multia-gency coalition, provide examples of how the SMART radars have contributed to research and education, and discuss future plans for continued development and management of the radar facility, including how others may use the radars for their own research and teaching programs.The capability of the SMART radars to measure winds in non-precipitating environments, to capture rapidly evolving, short-lived, small-scale tornadic circulations, and to sample mesoscale regions with high spatial resolution over broad regions of heavy rainfall is demonstrated. Repeated successful intercepts provide evidence that these radars are capable of being used to study a wide range of atmospheric phenomena.


Biggerstaff, Michael I.; Wicker, Louis J.; Guynes, Jerry; Ziegler, Conrad; Straka, Jerry M.; Rasmussen, Erik N.; Doggett, Arthur, IV; Carey, Larry D.; Schroeder, John L.; Weiss, Chris

2005-09-01

391

Research in space commercialization, technology transfer, and communications  

NASA Technical Reports Server (NTRS)

Research and internship programs in technology transfer, space commercialization, and information and communications policy are described. The intern's activities are reviewed. On-campus research involved work on the costs of conventional telephone technology in rural areas, an investigation of the lag between the start of a research and development project and the development of new technology, using NASA patent and patent waiver data, studies of the financial impact and economic prospects of a space operation center, a study of the accuracy of expert forecasts of uncertain quantities and a report on frequency coordination in the fixed and fixed satellite services at 4 and 6 GHz.

1982-01-01

392

Research on optic antenna of space laser communication networking  

NASA Astrophysics Data System (ADS)

With the highlights of the high transmission rate, large capacity, strong anti-interference and anti-capture ability, good security and small light, space laser communication becomes an important hotspot. At present, the focus of research of the laser communication system is point to point communication structure. However, from the application point of view, both the realization of space laser communication among multiple points and the establishment of the information transmission network can really have the practical value. Aiming at the problem of space laser communication network, this article puts forward the general idea about optical antenna to achieve multiple tracking goals at the same time. Through the analysis of the optical antenna, and the comparing of the current commonly used mirror driving mechanism, a new mirror driving mechanism is designed. The azimuth motion, containing circular grating feedback, is driven by torque motor?voice coil motor of fan produces pitch motion that has fan-shaped grating feedback, so that compression of the structure size to improve the efficiency of the reflector assembly. Through the establishment of the driving mechanism and the kinematic model of 3D entity, the relationship between the single drive azimuth and pitch angle following the angle of incident light is explained. The biggest ideal view area affecting the optical antenna is obtained by the simulation analysis of the kinematics model using MATLAB. The several factors of field overlap area and blind area offers a theoretical basis for structure optimization and control system for the subsequent optical antenna design.

Meng, Li-Xin; Li, Long; Zhang, Li-zhong; Zhao, Shan-shan; Jiang, Hui-lin

2013-08-01

393

Using mobile phones to engage citizen scientists in research  

NASA Astrophysics Data System (ADS)

Mobile phone-based tools have the potential to revolutionize the way citizen scientists are recruited and retained, facilitating a new type of “connected” citizen scientist—one who collects scientifically relevant data as part of his or her daily routine. Established citizen science programs collect information at local, regional, and continental scales to help answer diverse questions in the geosciences and environmental sciences. Hundreds of thousands of citizen scientists contribute to recurring research projects such as the Audubon Society's annual Christmas Bird Count, which drew more than 60,000 observers in 2009, or the U.S. Environmental Protection Agency's Volunteer Monitoring program, through which trained volunteers improve the monitoring of water quality in lakes and streams across the United States. These programs have relied on traditional recruiting techniques and written observations. New methods for engaging participants through technology, specifically, mobile applications, or apps, provide unprecedented ways for participants to have immediate access to their own and others' observations and research results.

Graham, Eric A.; Henderson, Sandra; Schloss, Annette

2011-09-01

394

Research on Automatic Testing Technology Oriented Intelligent Mobile Terminal Software  

Microsoft Academic Search

With the rapid development of ubiquitous computing technology, software is widely used in the intelligent mobile terminals. How to improve the intelligent mobile terminal software quality is one of the hot topics in embedded software testing field. Combined with the developed intelligent mobile terminal software automatic testing environment, the intelligent mobile terminal software testing script technology (TST-IMTS) was proposed firstly.

Yongfeng Yin; Bin Liu; Chen Wang; Hongying Ni

2010-01-01

395

Student Communication Behaviors and Their Influence on Teachers and Teaching in the American Classroom: A Review of Recent Communication Research.  

ERIC Educational Resources Information Center

This review of literature examines student communication behaviors and their influence on teachers and teaching. The purpose of this paper is two-fold. First, it reviews recent communication research that examines student communication behaviors and how their verbal and nonverbal messages have been shown to influence the instructional process in…

Mottet, Timothy P.

396

The projects of Disaster-Resistant Information Communication Network at the Research Organization of Electrical Communication, Tohoku University  

NASA Astrophysics Data System (ADS)

After the East Japan Great Earthquake, Tohoku University has established Research Organization of Electrical Communication to achieve the most advanced disaster-resistant information communication network in the world. In this paper, we will introduce our projects of "Disaster-Resistant Information Communication Network" based on industry-academia-government collaboration.

Iwatsuki, Katsumi

2012-12-01

397

Modeling and performance analysis of an improved movement-based location management scheme for packet-switched mobile communication systems.  

PubMed

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

Chung, Yun Won; Kwon, Jae Kyun; Park, Suwon

2014-01-01

398

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

NASA Technical Reports Server (NTRS)

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.

Peach, Robert; Malarky, Alastair

1990-01-01

399

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

NASA Technical Reports Server (NTRS)

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.

Haddad, H. A.

1948-01-01

400

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

NASA Technical Reports Server (NTRS)

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.

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

1993-01-01

401

Optimizing Communications Between Arctic Residents and IPY Scientific Researchers  

NASA Astrophysics Data System (ADS)

BACKGROUND International Polar Year, which was launched in March 2007, is an international program of coordinated, interdisciplinary scientific research on Earth's polar regions. The northern regions of the eight Arctic States (Canada, Alaska (USA), Russia, Sweden, Norway, Finland. Iceland and Greenland (Denmark) have significant indigenous populations. The circumpolar Arctic is one of the least technologically connected regions in the world, although Canada and others have been pioneers in developing and suing Information and Communication Technology (ICT) in remote areas. The people living in this vast geographic area have been moving toward taking their rightful place in the global information society, but are dependent on the outreach and cooperation of larger mainstream societies. The dominant medium of communication is radio, which is flexible in accommodating multiple cultures, languages, and factors of time and distance. The addition of newer technologies such as streaming on the Internet can increase access and content for all communities of interest, north and south. The Arctic Circle of Indigenous Communicators (ACIC) is an independent association of professional Northern indigenous media workers in the print, radio, television, film and Internet industries. ACIC advocates the development of all forms of communication in circumpolar North areas. It is international in scope. Members are literate in English, French, Russian and many indigenous languages. ACIC has proposed the establishment of a headquarters for monitoring IPY projects are in each area, and the use of community radio broadcasters to collect and disseminate information about IPY. The cooperation of Team IPY at the University of Colorado, Arctic Net at Laval University, and others, is being developed. ACIC is committed to making scientific knowledge gained in IPY accessible to those most affected - residents of the Arctic. ABSTRACT The meeting of the American Geophysical Union will be held in San Francisco on December 10 to 14, 2007. One component of this conference is entitled « Education, Outreach and Communications During IPY and Beyond ». ACIC proposes to present a discussion paper, « Optimizing Communications Between Arctic Residents and IPY Scientific Researchers », describing the status of IPY outreach and communications in the Arctic at this time. The paper will be complemented by photographs which illustrate the context of communication activity in these regions. ACIC has an existing international network of indigenous northern communicators. The IPY Northern Coordination Offices in Canada, and key informants in Alaska, RAIPON in the Russian Federation, and the Association of Sami Journalists, will be interviewed to determine involvement in IPY activities planned and/or undertaken. The level of community and professional awareness will be surveyed through interviews with community radio personnel. Aspirations and expectations for further cooperation with IPY reseearchers will be determined. Barriers and shortfalls will be identified. The usability and potential of current communications will be assessed. Endorsed IPY projects will be contacted to determine their Arctic communication plans and activities, barriers and opportunities. Information gained from the Joint Committee Assessment in October will be considered in the context of northern informant input. Conclusions and recommendations will reported, with the goal of optimizing opportunities to connect indigenous Arctic residents and IPY scientific research centres.

Stapleton, M.; Carpenter, L.

2007-12-01

402

The Use of Exploratory Factor Analysis and Principal Components Analysis in Communication Research.  

ERIC Educational Resources Information Center

Discusses the distinct purposes of principal components analysis (PCA) and exploratory factor analysis (EFA), using two data sets as examples. Reviews the use of each technique in three major communication journals: "Communication Monographs,""Human Communication Research," and "Communication Research." Finds that the use of EFA and PCA indicates…

Park, Hee Sun; Dailey, Rene; Lemus, Daisy

2002-01-01

403

Research activities in optical communications at Universite Laval  

Microsoft Academic Search

This paper presents a summary of some of the research activities conducted at the Centre d'optique, photonique et laser from Universite Laval that find applications in the field of optical communications. The subjects considered are: absolute frequency control, compensation of dispersion and nonlinear effects within dense wavelength division multiplexed systems, writing of in-fiber Bragg gratings, optical fast frequency-hopped code division

Michel Tetu; Pierre-Andre Belanger; Michel A. Duguay; Tigran V. Galstian; Christine Latrasse; Sophie Larochelle; Nathalie McCarthy; Claude Pare; Michel Piche; Leslie A. Rusch; Yunlong Sheng; Pierre J. Tremblay; Alain Villeneuve

1998-01-01

404

Scientific Mobility and International Research Networks: Trends and Policy Tools for Promoting Research Excellence and Capacity Building  

ERIC Educational Resources Information Center

One of the ways in which globalization is manifesting itself in higher education and research is through the increasing importance and emphasis on scientific mobility. This article seeks to provide an overview and analysis of current trends and policy tools for promoting mobility. The article argues that the mobility of scientific labour is an…

Jacob, Merle; Meek, V. Lynn

2013-01-01

405

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

NASA Technical Reports Server (NTRS)

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.

Castro, Jonathan P.

1993-01-01

406

Hysteresis in consumer markets with focus on the mobile communications market  

NASA Astrophysics Data System (ADS)

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.

Twomey, C.

2008-11-01

407

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

NASA Astrophysics Data System (ADS)

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.

Castro, Jonathan P.

408

Adaptive data rate SSMA system for personal and mobile satellite communications  

NASA Technical Reports Server (NTRS)

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.

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

1995-01-01

409

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

NASA Technical Reports Server (NTRS)

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.

Horstein, M.; Barnett, R.

1981-01-01

410

A high capacity mobile communications satellite system for the first generation MSS  

NASA Astrophysics Data System (ADS)

A low-cost high-capacity dual-band mobile communications satellite system using existing equipment is proposed for the first generation MSS. Cost effectiveness and the requirements of beam optimization and passive intermodulation avoidance dictated the choice of two single band satellites for separate UHF and L-band coverage of North America. Similar designs for the two satellites, based on the Intelsat V and Insat/Arabsat configurations, will achieve over 6000 5-kHz SCPC, communications channels for the system. The 12 beam UHF and 17 beam L-band satellites achieve up to a three-fold frequency reuse of the FCC allocated MSS frequency spectrum. Spacecraft design features include separate 9.1 m antennas for sending and receiving, SAW filters for channel noise attenuation, an integrated bipropellant propulsion system, and a 3.8 kW 10-year electrical power subsystem with a solar array. The satellites are compatible with the STS, Ariane, and other expendable boosters.

Wiedeman, R. A.

411

A VHE architecture for advanced value-added service provision in 3rd generation mobile communication networks  

Microsoft Academic Search

In the emerging era of 3rd generation mobile communication networks, it is expected that operator differentiation in the market will highly depend on the advanced provision of value-added services, including the successful implementation of the virtual home environment (VHE) concept. In this paper, after discussing some issues critical to VHE realization, we introduce a distributed application platform architecture, capable of

Nikos Houssos; Maria Koutsopoulou; Sibylle Schaller

2000-01-01

412

Performance Analysis of Maximal Ratio Combining and Comparison with Optimum Combining for Mobile Radio Communications with Cochannel Interference  

Microsoft Academic Search

The performance of maximal ratio combining for space diversity reception in digital cellular mobile radio systems is studied for communications in the presence of multiple cochannel interference (CCI) sources and is compared to optimum com- bining. The main contribution of the paper is that the analysis accounts for fading of the signal of interest (SOI) as well as the cochannel

A. Shah; A. M. Haimovich

2000-01-01

413

Performance analysis of maximal ratio combining and comparison with optimum combining for mobile radio communications with cochannel interference  

Microsoft Academic Search

The performance of maximal ratio combining for space diversity reception in digital cellular mobile radio systems is studied for communications in the presence of multiple cochannel interference (CCI) sources and is compared to optimum combining. The main contribution of the paper is that the analysis accounts for fading of the signal of interest (SOI) as well as the cochannel interference

A. Shah; A. M. Haimovich

2000-01-01

414

Performance of multi-level QAM with maximal ratio combining space diversity for land mobile radio communications  

Microsoft Academic Search

A novel type of space diversity with maximal ratio combining for multilevel quadrature amplitude modulation (QAM) in land mobile communications to improve transmission performance is proposed. In order to realize maximal ratio combining space diversity for QAM, a novel type of diversity combining method using a pilot symbol insertion type fading estimator is applied. The proposed diversity combining is carried

S. Sampei; T. Sunaga

1990-01-01

415

A novel channel estimation method for OFDM mobile communication systems based on pilot signals and transform-domain processing  

Microsoft Academic Search

A method of estimating the channel transfer function is presented for orthogonal frequency division multiplexing (OFDM) mobile communication systems working under time-variant radio channel conditions. The proposed method employs lowpass filtering in a transform domain so that intercarrier interference and additive white Gaussian noise components in the received pilot signals are significantly reduced. The cutoff frequency of the transform-domain filter

Yuping Zhao; Aiping Huang

1997-01-01

416

Market and committee-based mechanisms in the creation and diffusion of global industry standards: the case of mobile communication  

Microsoft Academic Search

The existing literature on industrial standards almost exclusively focuses on pure market competition; this paper shows how and why both governments and firms have had a strong effect on the creation of global standards in the mobile communication industry through a hybrid system of committees and markets. According to our model, governments can and did influence forecasted and actual installed

Jeffrey L. Funk; David T. Methe

2001-01-01

417

The Investigation of Cloud-Computing-based Image Mining Mechanism in Mobile Communication WEB on Android  

Microsoft Academic Search

With the development of 3G network technology, the rapid upgrading of mobile phone hardware, and the refined requirements for mobile phones by mobile phone users, it is essential for mobile phones to be able to promptly and accurately process images. A mobile phone terminal sends the service requests to cloud computer system which then processes the requests and sends the

Cai-Dong Gu; Kan Lu; Jian-Ping Wu; Ying-li Fu; Jing-xiang Li; Chang-shui Xiao; Mao-xin Si; Zhao-bin Liu

2010-01-01

418

Security, Privacy, Trust, and Resource Management in Mobile and Wireless Communications  

Microsoft Academic Search

Mobile cloud computing has grown out of two hot technology trends, mobility and cloud. The emergence of cloud computing and its extension into the mobile domain creates the potential for a global, interconnected mobile cloud computing environment that will allow the entire mobile ecosystem to enrich their services across multiple networks. We can utilize significant optimization and increased operating power

Hassan Takabi; James B. D. Joshi

2013-01-01

419

PROCEEDINGS OF THE ROTTERDAM MOBILITY RESEARCH CONFERENCE (ROTTERDAM, THE NETHERLANDS, AUGUST 3-7, 1964).  

ERIC Educational Resources Information Center

THESE PROCEEDINGS WERE PREPARED FROM THE MOBILITY RESEARCH CONFERENCE HELD IN ROTTERDAM, THE NETHERLANDS, AUGUST 3-7, 1964. PROGRESS REPORTS ARE GIVEN ON THE FOLLOWING--(1) ULTRASONIC MOBILITY AID, (2) ULTRASONIC GUIDANCE SYSTEM, (3) ELEKTROFTALM MOBILITY AID, (4) PASSIVE ENVIRONMENT SENSORS, (5) AMBIENT-LIGHT OBJECT DETECTOR, (6) TRAVEL PATH…

CLARK, LESLIE L.; AND OTHERS

420

Research of Temperature Measuring Virtual Instrument Based on Smart Mobile Phone  

Microsoft Academic Search

A temperature measuring virtual instrument based on smart mobile phone is introduced in this paper. The research was mainly done about the mobile phone hardware platform combined with general purpose software developing tools to be used as virtual instrument for data acquisition and signal process. This novel idea was realized on the smart mobile phone of Nokia N91 used for

Pingchuan Zhang; Buyin Li; Zhaoxiang Huang; Maosheng Shen; Jia Liu

2009-01-01

421

MoLeNET Mobile Learning Conference 2009: Research Papers  

ERIC Educational Resources Information Center

The Mobile Learning Network (MoLeNET) is a unique collaborative approach to encouraging, supporting, expanding and promoting mobile learning, primarily in English post-14 education and training, via supported shared cost mobile learning projects. Collaboration at national level involves participating institutions and the Learning and Skills…

Guy Parker, Ed.

2010-01-01

422

A survey of mobility models for ad hoc network research  

Microsoft Academic Search

In the performance evaluation of a protocol for an ad hoc network, the protocol should be tested under realistic conditions including, but not limited to, a sensible transmission range, limited buffer space for the storage of messages, representative data traffic models, and realistic movements of the mobile users (i.e., a mobility model). This paper is a survey of mobility models

Tracy Camp; Jeff Boleng; Vanessa Davies

2002-01-01

423

Identifying Research Priorities and Needs in Mobile Learning Technologies for Distance Education: A Delphi Study  

ERIC Educational Resources Information Center

The main purpose of this study was to identify, categorize and rank the future research priorities and needs for mobile learning technologies. The key research inquiries were the following: (a) What are the major research issues and challenges identified by online workers for mobile learning technologies over the next ten years?, (b) What are the…

Kurubacak, Gulsun

2007-01-01

424

Communication and Research Productivity in an Interdisciplinary Behavioral Science Research Area.  

ERIC Educational Resources Information Center

The nature of the relationship between communication behavior and research productivity is examined in this report. The purpose of the study was to attempt to explain variance in scientists' and scholars' research productivity using a variety of predictors. Data for the study were collected on questionnaires sent to 662 persons selected from…

Parker, Edwin B.,; And Others

425

OSI-compatible protocols for mobile-satellite communications: The AMSS experience  

NASA Technical Reports Server (NTRS)

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.

Moher, Michael

1990-01-01

426

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)

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.

Wilcox, R. E.

1985-01-01

427

Performance of the unique-word-reverse-modulation type demodulator for mobile satellite communications  

NASA Technical Reports Server (NTRS)

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).

Dohi, Tomohiro; Nitta, Kazumasa; Ueda, Takashi

1993-01-01

428

A new coherent demodulation technique for land-mobile satellite communications  

NASA Astrophysics Data System (ADS)

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.

Yoshida, Shousei; Tomita, Hideho

429

Requirements for a mobile communications satellite system. Volume 3: Large space structures measurements study  

NASA Technical Reports Server (NTRS)

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.

Akle, W.

1983-01-01

430

A new coherent demodulation technique for land-mobile satellite communications  

NASA Technical Reports Server (NTRS)

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.

Yoshida, Shousei; Tomita, Hideho

1990-01-01

431

Mobile Sensor Technologies Being Developed.  

National Technical Information Service (NTIS)

The NASA Glenn Research Center is developing small mobile platforms for sensor placement, as well as methods for communicating between roving platforms and a central command location. The first part of this project is to use commercially available equipme...

L. C. Greer L. G. Oberle

2003-01-01

432

7 CFR 3022.8 - Communication of research misconduct policies and procedures.  

Code of Federal Regulations, 2011 CFR

...2011-01-01 false Communication of research misconduct policies and procedures...FINANCIAL OFFICER, DEPARTMENT OF AGRICULTURE RESEARCH INSTITUTIONS CONDUCTING USDA-FUNDED EXTRAMURAL RESEARCH; RESEARCH MISCONDUCT § 3022.8...

2011-01-01

433

7 CFR 3022.8 - Communication of research misconduct policies and procedures.  

...2014-01-01 false Communication of research misconduct policies and procedures...FINANCIAL OFFICER, DEPARTMENT OF AGRICULTURE RESEARCH INSTITUTIONS CONDUCTING USDA-FUNDED EXTRAMURAL RESEARCH; RESEARCH MISCONDUCT § 3022.8...

2014-01-01

434

7 CFR 3022.8 - Communication of research misconduct policies and procedures.  

Code of Federal Regulations, 2012 CFR

...2012-01-01 false Communication of research misconduct policies and procedures...FINANCIAL OFFICER, DEPARTMENT OF AGRICULTURE RESEARCH INSTITUTIONS CONDUCTING USDA-FUNDED EXTRAMURAL RESEARCH; RESEARCH MISCONDUCT § 3022.8...

2012-01-01

435

7 CFR 3022.8 - Communication of research misconduct policies and procedures.  

Code of Federal Regulations, 2013 CFR

...2013-01-01 false Communication of research misconduct policies and procedures...FINANCIAL OFFICER, DEPARTMENT OF AGRICULTURE RESEARCH INSTITUTIONS CONDUCTING USDA-FUNDED EXTRAMURAL RESEARCH; RESEARCH MISCONDUCT § 3022.8...

2013-01-01

436

Research on the influence of communication delay on safety location of train in communication based train control (CBTC)  

Microsoft Academic Search

For the problems of the communication delay influence on the safety location in control system, research has been done for the delay of communication with different system structures of control and length of data frame. According to numerical results, the comparison between basic access and RTS\\/CTS can be seen clearly. The results show that under the current condition in CBTC,

Lijie Chen; Tao Tang

2009-01-01

437

Report on a Round Table "Communication 1980" on Mass Communication Research and Policy. Hanko, Finland, April 9-11, 1970.  

ERIC Educational Resources Information Center

The papers presented at the conference fall into three main categories: 1) outlines for critical research into mass communication, 2) international perspectives in broadcasting, and 3) the functions and goals of mass communication, together with problems of democratic control over broadcasting. All papers have been translated into English, as have…

Finnish Broadcasting Co., Helsinki.

438

Research and Application of Reverse Mobile Commerce Platform  

Microsoft Academic Search

Reverse Mobile Commerce Platform is an innovative e-commerce mode that reverses the traditional business process of e-commerce. Commodities traded on such platform are invisible information such as certain public idea, opinion, knowledge, comment and experience etc. This paper sets out to put forward the ideology and system constitution of Reverse Mobile Commerce Platform, and make detailed description of its operational

Hu Zhiyong

2009-01-01

439

Research on mobile cloud computing: Review, trend and perspectives  

Microsoft Academic Search

Mobile Cloud Computing (MCC) which combines mobile computing and cloud computing, has become one of the industry buzz words and a major discussion thread in the IT world since 2009. As MCC is still at the early stage of development, it is necessary to grasp a thorough understanding of the technology in order to point out the direction of future

Han Qi; Abdullah Gani

2012-01-01

440

The research of mobile IP handover technology in LEO spacecraft  

Microsoft Academic Search

To reduce high handover latency in Mobile IP applied between the spacecraft and ground stations, a handover scheme of Mobile IP based on the orbit information predetermination is proposed. The access time for each ground station and the access sequence are predicted in advance according to the spacecraft orbit information and the access stations location information, and then trigger the

Fu-sheng Dai; Yu-dong Feng; Gong-liang Liu

2010-01-01

441

Research for Particulate Control. EPA's Mobile Test Vans.  

National Technical Information Service (NTIS)

This report discusses EPA's mobile vans and their use in on-site aerosol monitoring. It contains a complete explanation of what is involved in hosting a mobile particulate control van at a plant, including specifications for installation and operation of ...

1979-01-01

442

Q-Method 20 Years Later: Its Uses and Abuses in Communications Research.  

ERIC Educational Resources Information Center

William Stephenson's Q methodology has been linked to the future of communications research by some and condemned as treacherous by others. This study reviews the uses of Q in published mass communications research over the past 20 years. The survey found 30 mass communications studies published in English in the scholarly journals related to mass…

Freeman, Leonard

443

The new frontier of communications research: smart grid and smart metering  

Microsoft Academic Search

This paper discusses some of the challenges and opportunities of communications research in the area of smart grids and smart metering. It is clear that the communications research community has been actively seeking the 'next big thing' after interests in recent hot topics such as cognitive radio, cooperative communications, and MIMO have more or less peaked. We argue that the

Zhong Fan; Georgios Kalogridis; Costas Efthymiou; Mahesh Sooriyabandara; Mutsumu Serizawa; Joe McGeehan

2010-01-01

444

An Individual's Experience: A Socio-Cultural Critique of Communication Apprehension Research  

ERIC Educational Resources Information Center

The purpose of this study was to understand what it could mean to have communication apprehension (CA). Literature that focuses on the research and theoretical aspects of communication apprehension was collected. From this research the concept of communication apprehension was conceptually defined, tools for measuring this phenomenon were…

Alley-Young, Gordon

2005-01-01

445

New Approaches to Human Mobility: Using Mobile Phones for Demographic Research  

PubMed Central

This article explores new methods for gathering and analyzing spatially rich demographic data using mobile phones. It describes a pilot study (the Human Mobility Project) in which volunteers around the world were successfully recruited to share GPS and cellular tower information on their trajectories and respond to dynamic, location-based surveys using an open-source Android application. The pilot study illustrates the great potential of mobile phone methodology for moving spatial measures beyond residential census units and investigating a range of important social phenomena, including the heterogeneity of activity spaces, the dynamic nature of spatial segregation, and the contextual dependence of subjective well-being.

Palmer, John R.B.; Espenshade, Thomas J.; Bartumeus, Frederic; Chung, Chang Y.; Ozgencil, Necati Ercan; Li, Kathleen

2012-01-01

446

Free Space Optical and RF Communications Testbed for Research and Education in Scalable Networks.  

National Technical Information Service (NTIS)

We have procured advanced communications and test equipment to further our research on scalable communication networks, hybrid free-space- optical (FSO) RF links and networks, and directional within networks.

C. C. Davis S. D. Milner Q. Balzano

2005-01-01

447

Performance of a Joint CDMA\\/PRMA Protocol for Mixed Voice\\/Data Transmission for Third Generation Mobile Communication  

Microsoft Academic Search

A joint code-division multiple-access\\/packet-reservation multiple-access (CDMA\\/PRMA) technique is proposed and investigated as a candidate for an uplink protocol for third generation mobile communication systems. Access to the radio channel is controlled such that compared to random access CDMA, interference variance is reduced and throughput increased. Mixed voice\\/data traffic is investigated for an isolated cell only, whereas voice-only traffic is also

Alex E. Brand; Hamid Aghvami

1996-01-01

448

Field Testing of a Remote Controlled Robotic Tele-echo System in an Ambulance Using Broadband Mobile Communication Technology  

Microsoft Academic Search

We report the testing of a mobile Robotic Tele-echo system that was placed in an ambulance and successfully transmitted clear\\u000a real time echo imaging of a patient's abdomen to the destination hospital from where this device was being remotely operated.\\u000a Two-way communication between the paramedics in this vehicle and a doctor standing by at the hospital was undertaken. The\\u000a robot

Ryohei Takeuchi; Hiroshi Harada; Kohji Masuda; Gen-ichiro Ota; Masaki Yokoi; Nobuyasu Teramura; Tomoyuki Saito

2008-01-01

449

A High Speed, Long-Range Mobile Communications Link for use in Polar Regions  

NASA Astrophysics Data System (ADS)

The Polar Radar for Ice Sheet Measurements (PRISM) project has developed a high bandwidth, wireless communications link between an autonomous rover and a manned vehicle deployed on a polar ice sheet to exchange real-time video, timing signals for a bistatic radar, and rover sensory data. The PRISM project is developing advanced intelligent remote sensing technology that involves radar systems, an autonomous rover, and communications systems to measure detailed ice sheet characteristics, and to determine bed conditions (frozen or wet) below active ice sheets in both Greenland and Antarctica. While this wireless communications link is being developed to fill a need within the PRISM Project, the same technology will allow polar researchers separated by moderate distances ( ˜10 km) to exchange data. The communications link is based on a high data rate 802.11b wireless technology, and a prototype system has been tested and evaluated during field experiments conducted at the NorthGRIP ice core drilling camp in Greenland (75° 06\\'\\ N, 42° 20\\'\\ W) from June 23-July 17, 2003. The IEEE 802.11b standard works in the 2.4-2.483 GHz band and has been widely used for high-speed data transfer in a WLAN (Wireless Local Area Network). It typically has a range of a few hundred meters and theoretical data rates on the order of 11 Mbps. It has been used for a number of applications in home and office environments. We modified a 802.11b system to operate up to a maximum distance of about 8 km and investigated the radio propagation environment over the flat terrain of the Greenland ice sheet. We evaluated its performance along three different tracks of 8 km in length, and made throughput measurements at intervals of 0.5 km. We measured the received signal strength and noise level in 2-s intervals along these 8 km tracks. Also we conducted experiments for four different antenna heights (1, 2, 3 and 5 m) for developing a radio propagation model for WLAN communication over the ice sheet. We found that peer-to-peer communication between nodes on the ice had data rates varying from 4.5 Mbps at close range to 2.5 Mbps at a distance of 8 km from the base station. The design, propagation model, throughput and coverage of this peer-to-peer communications system in Greenland are presented in this paper. This WLAN system has numerous applications in polar field camps. We tested the transfer of real-time video segments across this link for our educational outreach efforts in the field. These video segments were subsequently uploaded using an Iridium-based Internet link, and sent back to the University of Kansas. The wireless Internet connectivity was also made available to members of the North Grip camp, who were able to access e-mail and the Internet from their tents and common areas. However, throughput for wireless access to the Internet was limited by the Iridium-based Internet connection that had a maximum bandwidth of 9.6 Kbps.

Chalishazar, N.; Prescott, G.; Braaten, D.

2003-12-01

450

MobiCloud: Building Secure Cloud Framework for Mobile Computing and Communication  

Microsoft Academic Search

Cloud services can greatly enhance the computing capability of mobile devices. Mobile users can rely on the cloud to perform computationally intensive operations such as searching, data mining, and multimedia processing. In this paper, we propose a new mobile cloud framework called MobiCloud. In addition to providing traditional computation services, MobiCloud also enhances the operation of the ad hoc network

Dijiang Huang; Xinwen Zhang; Myong Kang; Jim Luo

2010-01-01

451

Mobile Health Care: Towards a Commercialization of Research Results  

Microsoft Academic Search

During the last fours years a consortium of universities, hospitals and commercial companies has been working together for the development of innovative systems and services for mobile health care. Two major projects were financed by the European Union allowed us to develop a complete mobile healthcare system and validate it with extensive medical trials. MobiHealth1 and HealthService241 have developed a

Dimitri Konstantas; Richard Bults; Aart Van Halteren; Katarzyna Wac; Val Jones; Ing Widya; Rainer Herzog; Barbara Streimelweger; A. Meier; M. Schumacher

2006-01-01

452

Research on mobile electronic commerce security technology based on WPKI  

NASA Astrophysics Data System (ADS)

Through the in-depth study on the existing mobile e-commerce and WAP protocols, this paper presents a security solution of e-commerce system based on WPKI, and describes its implementation process and specific implementation details. This solution uniformly distributes the key used by the various participating entities , to fully ensure the confidentiality, authentication, fairness and integrity of mobile e-commerce payments, therefore has some pract ical value for improving the security of e-commerce system.

Zhang, Bo

2013-07-01

453

Weather Information Communication Technologies for Increased Safety and Mobility in the National Airspace System  

NASA Technical Reports Server (NTRS)

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.

Hilderman, Don R.

2006-01-01

454

Communicating bioastronautics research to students, families and the nation  

NASA Astrophysics Data System (ADS)

The National Space Biomedical Research Institute (NSBRI) is supporting the National Aeronautics and Space Administration's (NASA) education mission through a comprehensive Education and Public Outreach Program (EPOP) that communicates the excitement and significance of space biology to schools, families, and lay audiences. The EPOP is comprised of eight academic institutions: Baylor College of Medicine, Massachusetts Institute of Technology, Morehouse School of Medicine, Mount Sinai School of Medicine, Texas A&M University, University of Texas Medical Branch Galveston, Rice University, and the University of Washington. This paper describes the programs and products created by the EPOP to promote space life science education in schools and among the general public. To date, these activities have reached thousands of teachers and students around the US and have been rated very highly.

MacLeish, Marlene Y.; Moreno, Nancy P.; Thomson, William A.; Newman, Dava J.; Gannon, Patrick J.; Smith, Roland B.; Denton, Jon J.; James, Robert K.; Wilson, Craig; Sognier, Marguerite; Illman, Deborah L.

2005-05-01

455

Communicating bioastronautics research to students, families and the nation.  

PubMed

The National Space Biomedical Research Institute (NSBRI) is supporting the National Aeronautics and Space Administration's (NASA) education mission through a comprehensive Education and Public Outreach Program (EPOP) that communicates the excitement and significance of space biology to schools, families, and lay audiences. The EPOP is comprised of eight academic institutions: Baylor College of Medicine, Massachusetts Institute of Technology, Morehouse School of Medicine, Mount Sinai School of Medicine, Texas A&M University, University of Texas Medical Branch Galveston, Rice University, and the University of Washington. This paper describes the programs and products created by the EPOP to promote space life science education in schools and among the general public. To date, these activities have reached thousands of teachers and students around the US and have been rated very highly. PMID:15834996

MacLeish, Marlene Y; Moreno, Nancy P; Thomson, William A; Newman, Dava J; Gannon, Patrick J; Smith, Roland B; Denton, Jon J; James, Robert K; Wilson, Craig; Sognier, Marguerite; Illman, Deborah L

2005-01-01

456

Living flexibly? How Europe's science researchers manage mobility, fixed-term employment and life outside work  

Microsoft Academic Search

This paper draws from interviews with mobile science researchers to explore experiences of mobility and fixed-term employment in the EU. The paper takes a socio-legal approach, aiming to understand the contribution of EU law and policy to the resource framework within which career decisions are made. The high incidence of fixed-term employment and the expectation of geographic mobility in science

E. A. Oliver

2012-01-01

457

Communicators' Perceptions of Social Presence as a Function of Avatar Realism in Small Display Mobile Communication Devices  

Microsoft Academic Search

This study describes an experiment in which 126 participants engaged via a mobile telephone simulation that included a visual display in a discussion that required self-disclosure and affective evaluation of the other participant. Participants in same gender and mixed gender dyads were represented by avatars that varied in visual realism (unmodified video, modified video, graphic display, or no visual display)

Sin-hwa Kang; James H. Watt; Sasi Kanth Ala

2008-01-01

458

Heliophysics Research at the National Observatory of Athens: Communicating Science  

NASA Astrophysics Data System (ADS)

The term heliophysics refers to the physics that controls the system that is being defined by the Sun, the heliosphere and the surrounding planets. Today, we are aware that we people live within the extended atmosphere of a living star, the Sun. Although, the light that the Sun provides creates and sustains life on Earth, its variability gives birth to streams of high energetic particles and radiation which could be harmful for the human life. The magnetic field and the atmosphere of the Earth provide powerful shielding against these threats, making the Earth an oasis within the Universe were life is in place to evolve and grow. We should all keep in mind, however, that the fate of life at Earth is bounded to the way it responds to the variability of the Sun. This united system that is being analyzed through heliophysics demands the understanding of the processes that take place within and at the face of the Sun as well as the interaction of the solar plasma and the emitted radiation with the Earth and the rest of the planets. Research on heliophysics at the National Observatory of Athens focuses at the analysis of the effect of the stormy Sun to the Earth. With this respect we use data from energetic particles, recoded onboard an armada of spacecraft, trying to decode the impact of solar storms. Given the fact that heliophysics is a vital and dynamic part of our everyday life, great care is being devoted to the communication of our research results to the general public in Greece, participating at large public outreach events like the Researcher's Night and with lectures/presentations delivered regularly to a variety of audiences, but also at a worldwide scale as our team acts as the National contact point for the International Space Weather Initiative (ISWI). In this work we present vital facts of our dominant Sun, we illustrate its effect at Earth and we discuss the effectiveness of the communication techniques that have been used in order to promote heliophysics research at a wider public.

Malandraki, Olga; Papaioannou, Athanasios; Patsou, Ioanna; Tziotziou, Kostas

2014-05-01

459

Mobile Three Frequency Radar as Research Platform for Precipitation Profiling  

NASA Astrophysics Data System (ADS)

Precipitation profiling at the frequency bands of Ku, Ka and W bands are becoming increasingly popular in the studies of atmospheric microphysics. Ever since the introduction of Ku / Ka pair of frequencies for the Global Precipitation Measurement mission (GPM) and the success of W band in Cloudsat, the interest in precipitation profiling using these frequencies has increased. The profiling observations will also serve as ground validation instruments for several space missions such as GPM and EarthCARE [1]. In order to get better information to retrieve ice microphysics as well as to enhance sensitivity, we need to move from the standard S- and C-band weather radars to higher frequencies [2]. As was recently shown, the use of multi- frequency profiling yields important additional information compared to single-frequency radar mapping [3]. During the past four years a consortium of research, academic and private industries in Finland has been developing a flexible low-cost mobile three-band radar system for precipitation profiling. The feasibility of the concept is being demonstrated by implementing the Ku- and Ka-band part of the system. The antenna structure with antennas for Ku-, Ka- and W-band is completed allowing the pointing of all three antenna systems into the same direction during an azimuth and elevation scan. Using a freely programmable digital waveform generator and decoding electronics for the received data, the implementation of different wave form generation, compression and decoding schemes and their influence on the radar performance in the different bands can be evaluated and optimized. The modular design allows the connection of different transmitter control and receiver decoding units to any of the three band front-end electronics to evaluate the performance of different approaches in the various bands simultaneously. A real-time analysis software supports the data interpretation and system optimization during field tests. Via mobile internet connection and standard data formats the collected data can be made available for operative use. The mechanical integration on a standard car trailer allows the fast deployment to different locations. References [1] V. Chandrasekar, D. Moisseev, W. Schmidt, K. Rautiainen and A.-M Harri, "Scientific and engineering overview of the three frequency precipitation profiling radar at Helsinki" The 9th International Symposium on Advanced Environmental Monitoring and Modeling Helsinki, 2012. [2] V. Chandrasekar, H. Fukatsu and K. Mubarak, "Global mapping of attenuation at Ku- and Ka-band", IEEE Transactions on Geoscience and Remote Sensing, vol. 41, pp. 2166-2176, 2003 [3] J.Leinonen, D. Moisseev, V. Chandrasekar, J. Koskinen, "Mapping Radar Reflectivity Values of Snowfall Between Frequency Bands", IEEE Transactions on Geoscience and Remote Sensing, vol. 49, no.8, pp. 3047-3058, 2011 doi: 10.1109/TGRS.2011.2117432

Schmidt, Walter; Rautiainen, Kimmo; Harri, Ari-Matti

2014-05-01

460

Communications Technologies. The VTT Roadmaps.  

National Technical Information Service (NTIS)

The view of VTT (Technical Research Centre of Finland) on the development of selected information and communication technologies is presented. The views are given as technology roadmaps in the areas of interoperability and mobility in future networks, mic...

M. Sipila

2002-01-01

461

Research in space commercialization, technology transfer and communications, vol. 2  

NASA Technical Reports Server (NTRS)

Spectrum management, models for evaluating communications systems, and implications of communications regulations for NASA are considered as major parts of communications policy. Marketing LANDSAT products in developing countries, a political systems analysis of LANDSAT, and private financing and operation of the space operations center (space station) are discussed. Investment requirements, risks, government support, and other primary business and management considerations are examined.

Dunn, D. A.; Agnew, C. E.

1983-01-01

462

An Infrared Network for Mobile Computers  

Microsoft Academic Search

The PARCTAB infrared network provides a flexible infrastructure for research into wireless mobile computing. The network consists of a collection of room-sized cells each wired with a base station transceiver. Mobile computers communicate with transceivers through a carrier sense multiple access (CSMA) protocol and act as terminals for applications executing on remote hosts. Each mobile computer is represented by a

Norman Adams; Bill N. Schilit; Michael M. Tso; Roy Want

1993-01-01

463

A hierarchical framework model of mobile security  

Microsoft Academic Search

As wireless communications and mobile multimedia services are booming nowadays, systematic research of the overall aspects of mobile security is crucial. This paper presents a framework model for guiding the systematic investigation of mobile security. Based on the introduction of some background viewpoints of security targets from a novel perspective, the framework is described as a hierarchical model in which

Jun-Zhao Sun; Douglas Howie; Antti Koivisto; Jaakko Sauvola

2001-01-01

464

Research Issues of Privacy Access Control Model for Mobile Ad Hoc Healthcare Applications with XACML  

Microsoft Academic Search

Information privacy is usually concerned with the confidentiality of protected health information (PHI) such as electronic medical records (EMR). To meet the needs of highly mobile patients in healthcare scenarios, mobile devices such as personal digital assistants (PDAs) are being used for storing entire patient histories and physicals, research data collection forms, the physician's reference desk, current care plans, and

Patrick C. K. Hung; Jude Andrade; Yongming Chen; Ranny Huang; Miguel Vargas Martin; Yi Zheng

2007-01-01

465

Teacher Effectiveness, Mobility, and Attrition in Florida: A Descriptive Analysis. Research Brief  

ERIC Educational Resources Information Center

While there has been substantial research studying the factors that influence teachers' career decisions, there is far less literature on the relationship between teacher effectiveness, mobility, and attrition. In the paper "Teacher Effectiveness, Mobility, and Attrition in Florida: A Descriptive Analysis," Martin West and Matthew Chingos address…

National Center on Performance Incentives, 2008

2008-01-01

466

Orientation and Mobility for Blind Infants. Abstract XIII: Research & Resources on Special Education.  

ERIC Educational Resources Information Center

A federally funded research report, titled "The Development of a Program in Orientation and Mobility for Multi-Handicapped Blind Infants" by Randall Harley et al., is briefly summarized in this one-page abstract. The report discusses the development of the "Peabody Mobility Kit for Infants," a package of assessment and training materials for use…

ERIC Clearinghouse on Handicapped and Gifted Children, Reston, VA.

467

Train-Ground Communication in CBTC Based on 802.11b: Design and Performance Research  

Microsoft Academic Search

The 802.11b physical protocols applied in Communication Based Train Control (CBTC) train-ground communication system are simulated in this paper, and the simulation result is used to determine the AP distance. The train speed impact on physical FER is also studied by the simulation result. As a protocol used in a fully mobile outdoor environment, the packet delay and packets loss

Li Zhu; Yan Zhang; Bin Ning; Hailin Jiang

2009-01-01

468

Mobile Home Research: An Evaluation of Formaldehyde Problems in Residential Mobile Homes.  

National Technical Information Service (NTIS)

This report examines the problem of elevated formaldehyde levels in mobile homes. Two related and practical concerns are (1) to develop an indoor formaldehyde concentration that may be suggested as an adequate safety standard and (2) to determine if the p...

1980-01-01

469

Current and Future AAC Research Considerations for Adults with Acquired Cognitive and Communication Impairments  

Microsoft Academic Search

Adults with acquired language impairments secondary to stroke, traumatic brain injury, and neurodegenerative diseases are candidates for communication supports outside of the traditional restoration-based approaches to intervention. Recent research proves repeatedly that augmentative and alternative communication (AAC) provides a means for participation, engagement, conversation, and message transfer when individuals can no longer expect full return of pre-morbid communication skills and

Melanie Fried-Oken; David R. Beukelman; Karen Hux

2012-01-01

470

Integration between terrestrial-based and satellite-based land mobile communications systems  

NASA Technical Reports Server (NTRS)

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.

Arcidiancono, Antonio

1990-01-01

471

Selected Research and Development Topics on Aerospace Communications at NASA Glenn Research Center  

NASA Technical Reports Server (NTRS)

This presentation discusses some of the efforts on communications RD that have been performed or are currently underway at NASA Glenn Research Center. The primary purpose of this presentation is to outline some RD topics to serve as talking points for a Technical Interchange Meeting with the Ohio State University. The meeting is scheduled to take place at The ElectroScience Laboratory of the Ohio State University on February 24, 2014.

Miranda, Felix A.; Romanofsky, Robert R.; Nessel, James A.

2014-01-01

472

Manufacturing consent?: Media messages in the mobilization against HIV/AIDS in India and lessons for health communication.  

PubMed

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

Khan, Shamshad

2014-01-01

473

Comparative international analysis of radiofrequency exposure surveys of mobile communication radio base stations.  

PubMed

This paper presents analyses of data from surveys of radio base stations in 23 countries across five continents from the year 2000 onward and includes over 173,000 individual data points. The research compared the results of the national surveys, investigated chronological trends and compared exposures by technology. The key findings from this data are that irrespective of country, the year and cellular technology, exposures to radio signals at ground level were only a small fraction of the relevant human exposure standards. Importantly, there has been no significant increase in exposure levels since the widespread introduction of 3G mobile services, which should be reassuring for policy makers and negate the need for post-installation measurements at ground level for compliance purposes. There may be areas close to antennas where compliance levels could be exceeded. Future potential work includes extending the study to additional countries, development of cumulative exposure distributions and investigating the possibility of linking exposure measurements to population statistics to assess the distribution of exposure levels relative to population percentiles. PMID:22377680

Rowley, Jack T; Joyner, Ken H

2012-01-01

474

Architecture for delay-sensitive communications in mobile optical free-space networks  

Microsoft Academic Search

Mobile optical free space networks are an emerging architecture that can provide high speed connectivity between a ground-based backbone network and mobile users in challenging environments. In such a network traffic could be relayed by airborne or ground routers using wireless optical links. The variable nature of the wireless optical channel complicates support for real-time distributed applications demanding bounds on

I. Cardei; A. Pavan; R. Bettati

2005-01-01

475

Application of radio channel modelling to a planning tool in a mobile radio indoor communication system  

Microsoft Academic Search

For mobile radio systems, it is very important to know how the propagation medium performs at the right frequency and within the given geographical environment. When this environment is an indoor one, that is, when a mobile system is being deployed within a building, a number of new issues appear that pose a number of constraints and restrictions to the

Gema Vallejo-Cabrejas; P. Batolome-Pascual

1993-01-01

476

Traffic Capacity of Three Types of Common-User Mobile Radio Communication Systems  

Microsoft Academic Search

The traffic-carrying capability of three types of common-user mobile radio systems are derived and compared; they are also compared with a private-user system. The systems considered make use of multichannel capability for mobile units or a dispersed array of base stations, or both.

L. Schiff

1970-01-01

477

Agent Communication Network - A Mobile Agent Computation Model for Internet Applications  

Microsoft Academic Search

We propose a graph-based model, with a simulation, for the mobile agents to evolve over the Internet. Based on the concepts of Food Web (or Food Chain), one of the natural laws that we may use besides neural networks and genetic algorithms, we define an agent niche overlap graph and agent evolution states for the distributed computation of mobile agent

Timothy K. Shih

1999-01-01

478

Residential mobility, technology & social ties  

Microsoft Academic Search

This research uses the disruption associated with residential mobility, to develop a deeper theoretical understanding of the role of communication technology in the initiation, maintenances and dissolution of social relationships. Residential mobility is a common yet stressful event. It represents a natural experiment, because it puts people in a situation where some of their previous face-to-face interactions must stop or

Irina Shklovski

2006-01-01

479

Satellite-aided mobile radio concepts study: Concept definition of a satellite-aided mobile and personal radio communication system  

NASA Technical Reports Server (NTRS)

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.

Anderson, R. E.

1979-01-01

480

Mobility-Based Mobile Relay Selection in MANETs  

NASA Astrophysics Data System (ADS)

The future wireless mobile communication networks are expected to provide seamless wireless access and data exchange to mobile users. In particular, it is expected that the demand for ubiquitous data exchange between mobile users will increase with the widespread use of various wireless applications of the intelligent transportation system (ITS) and intelligent vehicles. Mobile ad hoc networks (MANETs) are one of the representative research areas pursuing the technology needed to satisfy the increasing mobile communication requirements. However, most of the works on MANET systems do not take into account the continuous and dynamic changes of nodal mobility to accommodate system design and performance evaluation. The mobility of nodes limits the reliability of communication between the source and the destination node since a link between two continuously moving nodes is established only when one node enters the transmission range of the other. To alleviate this problem, mobile relay has been studied. In particular, it is shown that relay selection is an efficient way to support nodal mobility in MANET systems. In this paper, we propose a mobility-based relay selection algorithm for the MANET environment. Firstly, we define the lifetime as the maximum link duration for which the link between two nodes remains active. Therefore, the lifetime indicates the reliability of the relay link which measures its capability to successfully support relayed communication when requested by the source node. Furthermore, we consider a series of realistic scenarios according to the randomness of nodal mobility. Thus, the proposed algorithm can be easily applied in practical MANET systems by choosing the appropriate node mobility behavior. The numerical results show that the improved reliability of the proposed algorithm's relayed communication is achieved with a proper number of mobile relay nodes rather than with the conventional selection algorithm. Lastly, we show that random mobility of the individual nodes enhances reliability of the network in a sparse network environment.

Kim, Gilnam; Lee, Hyoungjoo; Lee, Kwang Bok

481

A medical application integrating remote 3D visualization tools to access picture archiving and communication system on mobile devices.  

PubMed

With computing capability and display size growing, the mobile device has been used as a tool to help clinicians view patient information and medical images anywhere and anytime. However, for direct interactive 3D visualization, which plays an important role in radiological diagnosis, the mobile device cannot provide a satisfactory quality of experience for radiologists. This paper developed a medical system that can get medical images from the picture archiving and communication system on the mobile device over the wireless network. In the proposed application, the mobile device got patient information and medical images through a proxy server connecting to the PACS server. Meanwhile, the proxy server integrated a range of 3D visualization techniques, including maximum intensity projection, multi-planar r