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Sample records for access cdma mobile

  1. Use of CDMA access technology in mobile satellite systems

    NASA Technical Reports Server (NTRS)

    Ramasastry, Jay; Wiedeman, Bob

    1995-01-01

    Use of Code Division Multiple Access (CDMA) technology in terrestrial wireless systems is fairly well understood. Similarly, design and operation of Power Control in a CDMA-based system in a terrestrial environment is also well established. Terrestrial multipath characteristics, and optimum design of the CDMA receiver to deal with multipath and fading conditions are reliably established. But the satellite environment is different. When the CDMA technology is adopted to the satellite environment, other design features need to be incorporated (for example; interleaving, open-loop and closed-loop power control design, diversity characteristics) to achieve comparable level of system performance. In fact, the GLOBALSTAR LEO/MSS system has incorporated all these features. Contrary to some published reports, CDMA retains the advantages in the satellite environment that are similar to those achieved in the terrestrial environment. This document gives a description of the CDMA waveform and other design features adopted for mobile satellite applications.

  2. A satellite mobile communication system based on Band-Limited Quasi-Synchronous Code Division Multiple Access (BLQS-CDMA)

    NASA Technical Reports Server (NTRS)

    Degaudenzi, R.; Elia, C.; Viola, R.

    1990-01-01

    Discussed here is a new approach to code division multiple access applied to a mobile system for voice (and data) services based on Band Limited Quasi Synchronous Code Division Multiple Access (BLQS-CDMA). The system requires users to be chip synchronized to reduce the contribution of self-interference and to make use of voice activation in order to increase the satellite power efficiency. In order to achieve spectral efficiency, Nyquist chip pulse shaping is used with no detection performance impairment. The synchronization problems are solved in the forward link by distributing a master code, whereas carrier forced activation and closed loop control techniques have been adopted in the return link. System performance sensitivity to nonlinear amplification and timing/frequency synchronization errors are analyzed.

  3. Why is CDMA the solution for mobile satellite communication

    NASA Technical Reports Server (NTRS)

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

    1989-01-01

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

  4. Comparison of CDMA and FDMA for the MobileStar(sm) system

    NASA Technical Reports Server (NTRS)

    Jacobs, I. M.; Gilhousen, K. S.; Weaver, L. A.; Renshaw, K.; Murphy, T.

    1988-01-01

    Spread-spectrum code division multiple access (CDMA) and single channel per carrier frequency division multiple access (FDMA) systems are compared for spectrum efficiency. CDMA is shown to have greater maximum throughput than FDMA for the MobileStar(sm) system which uses digital voice activated carriers and directive circularly polarized satellite antennas.

  5. Mobile multiple access study

    NASA Technical Reports Server (NTRS)

    1977-01-01

    Multiple access techniques (FDMA, CDMA, TDMA) for the mobile user and attempts to identify the current best technique are discussed. Traffic loading is considered as well as voice and data modulation and spacecraft and system design. Emphasis is placed on developing mobile terminal cost estimates for the selected design. In addition, design examples are presented for the alternative techniques of multiple access in order to compare with the selected technique.

  6. Adaptive beamforming in a CDMA mobile satellite communications system

    NASA Technical Reports Server (NTRS)

    Munoz-Garcia, Samuel G.

    1993-01-01

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

  7. Adaptive digital beamforming for a CDMA mobile communications payload

    NASA Technical Reports Server (NTRS)

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

    1993-01-01

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

  8. Adaptive digital beamforming for a CDMA mobile communications payload

    NASA Astrophysics Data System (ADS)

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

    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

  9. First satellite mobile communication trials using BLQS-CDMA

    NASA Technical Reports Server (NTRS)

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

    1993-01-01

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

  10. Capacity of a spread spectrum CDMA system for cellular mobile radio with consideration of system imperfections

    NASA Astrophysics Data System (ADS)

    Newson, Paul; Heath, Mark R.

    1994-05-01

    There has been much interest in the use of spread spectrum code division multiple access (CDMA) techniques for cellular mobile radio. To date, spread spectrum has been used mainly for military applications, in which the inherent transmission security and immunity to deliberate jamming are important. Spread spectrum systems, however, possess various other features such as multiple access and multipath rejection capability, which make their use attractive within the mobile radio environment. However, the current interest has been principally motivated by recent work in which it is claimed that the CDMA option may offer capacity improvement over more conventional frequency and time division multiple access (FDMA) (TDMA) techniques. Within this paper, the relative capacities of a basic FDMA and CDMA system are examined. It is shown that, in the absence of capacity-enhancing features such as voice activity detection and cell sectorization, the capacity of each system is comparable. The paper then assesses the sensitivity of the CDMA system to typical propagation conditions, power control errors, and realistic antenna patterns and shows that the capacity of a CDMA system may be significantly reduced under nonideal conditions.

  11. Alternative multiple-access techniques for mobile satellite systems

    NASA Technical Reports Server (NTRS)

    Smith, Patrick O.; Geraniotis, Evaggelos

    1989-01-01

    The use of Code Division Multiple Access (CDMA) to satisfy the diverse requirements of a generic (land, maritime, aeronautical) mobile satellite system (MSS) network design is discussed. Comparisons between CDMA and Frequency Division Multiple Access (FDMA) show that a CDMA network design can support significantly more voice channel allocations than FDMA when relatively simple CDMA correlation receivers are employed, provided that there is sufficient space segment equivalent isotropically radiated power (EIRP). The use of more advanced CDMA receivers can improve the spectral and power efficiency. Although the use of CDMA may not gain immediate and widespread support in the international MSS community, provision for the use of CDMA for a domestic system in the U.S., and possibly for a regional system throughout North America, is likely.

  12. Handover aspects for a Low Earth Orbit (LEO) CDMA Land Mobile Satellite (LMS) system

    NASA Astrophysics Data System (ADS)

    Carter, P.; Beach, M. A.

    This paper addresses the problem of handoff in a land mobile satellite (LMS) system between adjacent satellites in a low earth orbit (LEO) constellation. In particular, emphasis is placed on the application of soft handoff in a direct sequence code division multiple access (DS-CDMA) LMS system. Soft handoff is explained in terms of terrestrial macroscopic diversity, in which signals transmitted via several independent fading paths are combined to enhance the link quality. This concept is then reconsidered in the context of a LEO LMS system. A two-state Markov channel model is used to simulate the effects of shadowing on the communications path from the mobile to each satellite during handoff. The results of the channel simulation form a platform for discussion regarding soft handoff, highlighting the potential merits of the scheme when applied in a LEO LMS environment.

  13. Handover aspects for a Low Earth Orbit (LEO) CDMA Land Mobile Satellite (LMS) system

    NASA Technical Reports Server (NTRS)

    Carter, P.; Beach, M. A.

    1993-01-01

    This paper addresses the problem of handoff in a land mobile satellite (LMS) system between adjacent satellites in a low earth orbit (LEO) constellation. In particular, emphasis is placed on the application of soft handoff in a direct sequence code division multiple access (DS-CDMA) LMS system. Soft handoff is explained in terms of terrestrial macroscopic diversity, in which signals transmitted via several independent fading paths are combined to enhance the link quality. This concept is then reconsidered in the context of a LEO LMS system. A two-state Markov channel model is used to simulate the effects of shadowing on the communications path from the mobile to each satellite during handoff. The results of the channel simulation form a platform for discussion regarding soft handoff, highlighting the potential merits of the scheme when applied in a LEO LMS environment.

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

    NASA Astrophysics Data System (ADS)

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

    2006-03-01

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

  15. Comparison of FDMA and CDMA for second generation land-mobile satellite communications

    NASA Technical Reports Server (NTRS)

    Yongacoglu, A.; Lyons, R. G.; Mazur, B. A.

    1990-01-01

    Code Division Multiple Access (CDMA) and Frequency Division Multiple Access (FDMA) (both analog and digital) systems capacities are compared on the basis of identical link availabilities and physical propagation models. Parameters are optimized for a bandwidth limited, multibeam environment. For CDMA, the benefits of voice activated carriers, antenna discrimination, polarization reuse, return link power control and multipath suppression are included in the analysis. For FDMA, the advantages of bandwidth efficient modulation/coding combinations, voice activated carriers, polarization reuse, beam placement, and frequency staggering were taken into account.

  16. Application of neural networks to channel assignment for cellular CDMA networks with multiple services and mobile base stations

    NASA Astrophysics Data System (ADS)

    Hortos, William S.

    1996-03-01

    The use of artificial neural networks to the channel assignment problem for cellular code- division multiple access (CDMA) telecommunications systems is considered. CDMA takes advantage of voice activity and spatial isolation because its capacity is only interference limited, unlike time-division multiple access (TDMA) and frequency-division multiple access (FDMA) where capacities are bandwidth limited. Any reduction in interference in CDMA translates linearly into increased capacity. FDMA and TDMA use a frequency reuse pattern as a method to increase capacity, while CDMA reuses the same frequency for all cells and gains a reuse efficiency by means of orthogonal codes. The latter method can improve system capacity by factors of four to six over digital TDMA or FDMA. Cellular carriers are planning to provide multiple communication services using CDMA in the next generation cellular system infrastructure. The approach of this study is the use of neural network methods for automatic and local network control, based on traffic behavior in specific cell cites and demand history. The goal is to address certain problems associated with the management of mobile and personal communication services in a cellular radio communications environment. In planning a cellular radio network, the operator assigns channels to the radio cells so that the probability of the processed carrier-to-interference ratio, CII, exceeding a predefined value is sufficiently low. The RF propagation, determined from the topography and infrastructure in the operating area, is used in conjunction with the densities of expected communications traffic to formulate interference constraints. These constraints state which radio cells may use the same code (channel) or adjacent channels at a time. The traffic loading and the number of service grades can also be used to calculate the number of required channels (codes) for each cell. The general assignment problem is the task of assigning the required number

  17. Sharing possibilities amongst CDMA Mobile Satellite Systems, and impacts of terminal characteristics on sharing

    NASA Astrophysics Data System (ADS)

    Bambace, Luís Antonio Waack; Ceballos, Décio Castilho

    CDMA Mobile Satellite Systems (CDMA MSS) are able to co-directional, co-frequency and co-coverage sharing, and they are strongly interdependent in case of such a sharing. It is also known that the success of any telecommunication project is the use of the correct media to each task. Operators have a clear sight of such a media adequacy in traditional systems, but not necessarily in the case of Mobile Satellite Systems. This creates a risk that a wrong market objective operator causes trouble to other systems. This paper deals with the sharing alternatives for up to four CDMA MSS operating in the same frequency band, and analysts both: satellite to user downlink and user to satellite uplink. The influence of several items in capacity is here treated. The scope includes: downlink power flux density: code availability; single system internal interference; inter-system interference; diversity schemes: average link impairments, margins; user cooperation; terminal specifications and the dependence of the insulation between RHCP and LHCP with fade.

  18. Secure Communications in High Speed Fiber Optical Networks Using Code Division Multiple Access (CDMA) Transmission

    SciTech Connect

    Han, I; Bond, S; Welty, R; Du, Y; Yoo, S; Reinhardt, C; Behymer, E; Sperry, V; Kobayashi, N

    2004-02-12

    This project is focused on the development of advanced components and system technologies for secure data transmission on high-speed fiber optic data systems. This work capitalizes on (1) a strong relationship with outstanding faculty at the University of California-Davis who are experts in high speed fiber-optic networks, (2) the realization that code division multiple access (CDMA) is emerging as a bandwidth enhancing technique for fiber optic networks, (3) the realization that CDMA of sufficient complexity forms the basis for almost unbreakable one-time key transmissions, (4) our concepts for superior components for implementing CDMA, (5) our expertise in semiconductor device processing and (6) our Center for Nano and Microtechnology, which is where the majority of the experimental work was done. Here we present a novel device concept, which will push the limits of current technology, and will simultaneously solve system implementation issues by investigating new state-of-the-art fiber technologies. This will enable the development of secure communication systems for the transmission and reception of messages on deployed commercial fiber optic networks, through the CDMA phase encoding of broad bandwidth pulses. CDMA technology has been developed as a multiplexing technology, much like wavelength division multiplexing (WDM) or time division multiplexing (TDM), to increase the potential number of users on a given communication link. A novel application of the techniques created for CDMA is to generate secure communication through physical layer encoding. Physical layer encoding devices are developed which utilize semiconductor waveguides with fast carrier response times to phase encode spectral components of a secure signal. Current commercial technology, most commonly a spatial light modulator, allows phase codes to be changed at rates of only 10's of Hertz ({approx}25ms response). The use of fast (picosecond to nanosecond) carrier dynamics of semiconductors, as

  19. Advanced multiple access concepts in mobile satellite systems

    NASA Technical Reports Server (NTRS)

    Ananasso, Fulvio

    1990-01-01

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

  20. Delay-bounded semi-reliable vital sign transmission protocol for mobile telemedicine over a CDMA 1x EV-DO network.

    PubMed

    Lee, Tong H; Yoo, Sun K

    2008-04-01

    The reliable and instant transmission of vital signs is important for remote time-critical patient care through a telemedicine system. However, sometimes the reliability and instantaneity conditions cannot be satisfied simultaneously under a high-noise mobile network, because they are reciprocal to each other. In this paper, the vital sign transmission protocol (VSTP) running over a CDMA 1x EVDO (Code Division Multiple Access 1x Evolution Data Only) mobile network is proposed to comply with both the reliability and instantaneity requirements. The switching buffer management scheme is combined with a hybrid error control scheme, consisting of forward error correction (FEC) and automatic repeat request (ARQ). The CDMA 1x EVDO mobile network is modeled by two states using the Markov wireless channel model to test transmission performance under diverse network conditions. Throughout the noisy environment simulation, the performance of the VSTP is compared with the Transmission Control Protocol (TCP) and User Datagram Protocol (UDP) to demonstrate its efficacy over error-prone mobile network.

  1. Influence of Mobile Users' Density Distribution on the CDMA Base Station Power

    NASA Astrophysics Data System (ADS)

    Lebl, Aleksandar; Mitić, Dragan; Popović, Miroslav; Markov, Žarko; Mileusnić, Mladen; Matić, Vladimir

    2016-12-01

    In this paper we analyze the influence of users' density distribution in one cell of CDMA mobile network (ie adjusted power control on the forward link) on base station emission power. This influence is analyzed for different circles radii around base station within which same emission power is generated for all mobile users, and for different values of propagation loss coefficient. It is proved that emission power in this cell must be increased comparing to the similar cell, which uses complete power control. The power increase is greater when greater number of users are situated near base station, and for greater values of propagation loss coefficient. The results are presented, illustrated by numerical examples and verified by simulation for three users' density distributions: uniform, decreasing and increasing density from the base station to the cell rim. The simulation process, which is based on random traffic process, is presented briefly.

  2. Synthesis and demonstration of high speed, bandwidth efficient optical Code Division Multiple Access (CDMA) tested at 1 Gb/s throughput

    NASA Astrophysics Data System (ADS)

    Mendez, Antonio J.; Lambert, James L.; Morookian, John-Michael; Gagliardi, Robert M.

    1994-09-01

    Code division multiple access (CDMA) permits concurrent communication over all virtual channels (in principle), independent of the data rate and the network size. In reality, most CDMA approaches have a bandwidth penalty due to the code length and a loss penalty due to the broadcasting required by CDMA. Both of these penalties can be reduced or ameliorated by means of multi-attribute coding. Matrices constructed from relatively inefficient (0, 1)pulse sequences are suitable multi-attribute non-coherent CDMA codes which are both bandwidth and broadcast efficient. We exhibit a novel approach to synthesizing matrix CDMA codes, develop a 4 x 4 physical model, and demonstrate concurrent communication experimentally at concurrent data rates of 100-, 150-, and 250 Mb/s per port.

  3. Mobile access control vestibule

    NASA Astrophysics Data System (ADS)

    DePoy, Jennifer M.

    1998-12-01

    The mobile access control vestibule (MACV) is an adaptation of techniques developed for mobile military command centers. The overall configuration of modules acts as an entry control/screening facility or transportable command center. The system would provide the following capabilities: (1) A key element for force protection, rapid deployment units sent to areas having no prepositioned equipment or where there has been a degradation of that equipment as a result of natural disasters or civil unrest. (2) A rapidly deployable security control center to upgrade the security at nonmilitary sites (e.g., diplomatic or humanitarian organizations). (3) Personnel screening, package screening, badge/identification card production for authorized personnel, centralized monitoring of deployed perimeter sensors, and centralized communications for law enforcement personnel. (4) Self-contained screening and threat detection systems, including explosives detection using the system developed by Sandia National Laboratories for the FAA. When coupled with transportable electric generators, the system is self-sufficient. The communication system for the MACV would be a combination of physically wired and wireless communication units that supports by ad hoc networking.

  4. System level comparison of FDMA vs. CDMA (under conference guideline constraint)

    NASA Technical Reports Server (NTRS)

    Renshaw, Ken

    1989-01-01

    The margin that is required to mitigate the near-far problem in a Code Division Multiple Access (CDMA) mobile satellite system is determined by the radio-propagation model selected, the distribution of the users in clear and shadowed environments, and implementation techniques. The use of revenue potential as a means of evaluating the relative merits of CDMA and Frequency Division Multiple Access (FDMA) systems is a convenient way to rationalize the performance of systems using high-gain and low-gain antennas. The revenue potential of CDMA is much greater than the revenue potential for FDMA for a particular satellite design considered.

  5. DNA strand breaks are not induced in human cells exposed to 2.1425 GHz band CW and W-CDMA modulated radiofrequency fields allocated to mobile radio base stations.

    PubMed

    Sakuma, N; Komatsubara, Y; Takeda, H; Hirose, H; Sekijima, M; Nojima, T; Miyakoshi, J

    2006-01-01

    We conducted a large-scale in vitro study focused on the effects of low level radiofrequency (RF) fields from mobile radio base stations employing the International Mobile Telecommunication 2000 (IMT-2000) cellular system in order to test the hypothesis that modulated RF fields may act as a DNA damaging agent. First, we evaluated the responses of human cells to microwave exposure at a specific absorption rate (SAR) of 80 mW/kg, which corresponds to the limit of the average whole body SAR for general public exposure defined as a basic restriction in the International Commission on Non-Ionizing Radiation Protection (ICNIRP) guidelines. Second, we investigated whether continuous wave (CW) and Wideband Code Division Multiple Access (W-CDMA) modulated signal RF fields at 2.1425 GHz induced different levels of DNA damage. Human glioblastoma A172 cells and normal human IMR-90 fibroblasts from fetal lungs were exposed to mobile communication frequency radiation to investigate whether such exposure produced DNA strand breaks in cell culture. A172 cells were exposed to W-CDMA radiation at SARs of 80, 250, and 800 mW/kg and CW radiation at 80 mW/kg for 2 and 24 h, while IMR-90 cells were exposed to both W-CDMA and CW radiations at a SAR of 80 mW/kg for the same time periods. Under the same RF field exposure conditions, no significant differences in the DNA strand breaks were observed between the test groups exposed to W-CDMA or CW radiation and the sham exposed negative controls, as evaluated immediately after the exposure periods by alkaline comet assays. Our results confirm that low level exposures do not act as a genotoxicant up to a SAR of 800 mW/kg.

  6. Mobile Data Access

    DTIC Science & Technology

    1998-05-11

    F19628-93-C-0193, the Intel Corporation, the National Science Foundation, AT&T, and Lucent Technologies . The views and conclusions contained herein...in other locations must resort to some alternative wireless technology ; moving between these technologies yields significant variation. There is one...supporting infrastructure, and poor security and robustness, are inherent to mobile systems and will not be ehminated by technological progress. The

  7. Proceedings of the Mobile Satellite System Architectures and Multiple Access Techniques Workshop

    NASA Technical Reports Server (NTRS)

    Dessouky, Khaled

    1989-01-01

    The Mobile Satellite System Architectures and Multiple Access Techniques Workshop served as a forum for the debate of system and network architecture issues. Particular emphasis was on those issues relating to the choice of multiple access technique(s) for the Mobile Satellite Service (MSS). These proceedings contain articles that expand upon the 12 presentations given in the workshop. Contrasting views on Frequency Division Multiple Access (FDMA), Code Division Multiple Access (CDMA), and Time Division Multiple Access (TDMA)-based architectures are presented, and system issues relating to signaling, spacecraft design, and network management constraints are addressed. An overview article that summarizes the issues raised in the numerous discussion periods of the workshop is also included.

  8. Optical fiber-based CDMA networks

    NASA Astrophysics Data System (ADS)

    Gameiro, Atilio M. S.

    1996-01-01

    In this communication we consider the use of an optical fiber based fixed infrastructure for code division multiple access (CDMA) mobile networks. In such a scenario, the base stations are linked to the central station through optical fiber using subcarrier multiplexing (SCM) technology. One of the major problems associated with optical SCM is the nonlinearity of the laser diodes (LD). In this communication we model the LD as a memoryless nonlinearity and evaluate the effect of the nonlinearity on the SCM transmission CDMA signals. We find that the behavior departs significantly from what happens in FDMA and depends critically on the nonlinearity of the LD being a compressing or an expanding one. In the former case significant performance degradation may occur whereas for the latter the degradation is usually not dramatic.

  9. Analysis of multiple access techniques in multi-satellite and multi-spot mobile satellite systems

    NASA Technical Reports Server (NTRS)

    Corazza, Giovanni E.; Ferrarelli, Carlo; Vatalaro, Francesco

    1995-01-01

    In this paper the analysis of mobile satellite systems adopting constellations of multi-spot satellites over non-geostationary orbits is addressed. A link design procedure is outlined, taking into account system spectrum efficiency, probability of bit error and outage probability. A semi-analytic approach to the evaluation of outage probability in the presence of fading and imperfect power control is described, and applied to single channel per carrier (SCPC) and code division multiple access (CDMA) techniques. Some results are shown for the Globalstar, Iridium and Odyssey orbital configurations.

  10. A CDMA synchronisation scheme

    NASA Technical Reports Server (NTRS)

    Soprano, C.

    1993-01-01

    CDMA (Code Division Multiple Access) is known to decrease inter-service interference in Satellite Communication Systems. Its performance is increased by chip quasi-synchronous operation which virtually eliminates the self-noise; however, the theory shows that the time error on the synchronization has to be kept at less than one tenth of a chip which, for 1 Mchip/sec. spreading rate, corresponds to 10(exp -7) sec. This, on the return-link, may only be achieved by means of a closed loop control system which, for mobile communication systems, has to be capable of autonomous operation. Until now some results have been reported on the feasibility of chip quasi-synchronous operation for mobile communication systems only including satellites on GEO (Geostationary Earth Orbit). In what follows, the basic principles are exposed, and results are presented showing how low chip synchronism error may be achieved by means of an autonomous control loop operating through satellites on any Earth orbit.

  11. Mobile and Accessible Learning for MOOCs

    ERIC Educational Resources Information Center

    Sharples, Mike; Kloos, Carlos Delgado; Dimitriadis, Yannis; Garlatti, Serge; Specht, Marcus

    2015-01-01

    Many modern web-based systems provide a "responsive" design that allows material and services to be accessed on mobile and desktop devices, with the aim of providing "ubiquitous access." Besides offering access to learning materials such as podcasts and videos across multiple locations, mobile, wearable and ubiquitous…

  12. Pilot-Assisted Adaptive Channel Estimation for Coded MC-CDMA with ICI Cancellation

    NASA Astrophysics Data System (ADS)

    Yui, Tatsunori; Tomeba, Hiromichi; Adachi, Fumiyuki

    One of the promising wireless access techniques for the next generation mobile communications systems is multi-carrier code division multiple access (MC-CDMA). MC-CDMA can provide good transmission performance owing to the frequency diversity effect in a severe frequency-selective fading channel. However, the bit error rate (BER) performance of coded MC-CDMA is inferior to that of orthogonal frequency division multiplexing (OFDM) due to the residual inter-code interference (ICI) after frequency-domain equalization (FDE). Recently, we proposed a frequency-domain soft interference cancellation (FDSIC) to reduce the residual ICI and confirmed by computer simulation that the MC-CDMA with FDSIC provides better BER performance than OFDM. However, ideal channel estimation was assumed. In this paper, we propose adaptive decision-feedback channel estimation (ADFCE) and evaluate by computer simulation the average BER and throughput performances of turbo-coded MC-CDMA with FDSIC. We show that even if a practical channel estimation is used, MC-CDMA with FDSIC can still provide better performance than OFDM.

  13. Design and Evaluation of a Virtual Quadrant Receiver for 4-ary Pulse Position Modulation/Optical Code Division Multiple Access (4-ary PPM/O-CDMA)

    SciTech Connect

    Mendez, A J; Hernandez, V J; Gagliardi, R M; Bennett, C V

    2006-12-29

    M-ary pulse position modulation (M-ary PPM) is an alternative to on-off-keying (OOK) that transmits multiple bits as a single symbol occupying a frame of M slots. PPM does not require thresholding as in OOK signaling, instead performing a comparison test among all slots in a frame to make the slot decision. Combining PPM with optical code division multiple access (PPM/O-CDMA) adds the benefit of supporting multiple concurrent, asynchronous bursty PPM users. While the advantages of PPM/O-CDMA are well known, implementing a receiver that performs comparison test can be difficult. This paper describes the design of a novel array receiver for M-ary PPM/O-CDMA (M = 4) where the received signal is mapped onto an xy-plane whose quadrants define the PPM slot decision by means of an associated control law. The receiver does not require buffering or nonlinear operations. In this paper we describe a planar lightwave circuit (PLCs) implementation of the receiver. We give detailed numerical simulations that test the concept and investigate the effects of multi-access interference (MAI) and optical beat interference (OBI) on the slot decisions. These simulations provide guidelines for subsequent experimental measurements that will be described.

  14. Performance enhancement of MC-CDMA system through novel sensitive bit algorithm aided turbo multi user detection.

    PubMed

    Kumaravel, Rasadurai; Narayanaswamy, Kumaratharan

    2015-01-01

    Multi carrier code division multiple access (MC-CDMA) system is a promising multi carrier modulation (MCM) technique for high data rate wireless communication over frequency selective fading channels. MC-CDMA system is a combination of code division multiple access (CDMA) and orthogonal frequency division multiplexing (OFDM). The OFDM parts reduce multipath fading and inter symbol interference (ISI) and the CDMA part increases spectrum utilization. Advantages of this technique are its robustness in case of multipath propagation and improve security with the minimize ISI. Nevertheless, due to the loss of orthogonality at the receiver in a mobile environment, the multiple access interference (MAI) appears. The MAI is one of the factors that degrade the bit error rate (BER) performance of MC-CDMA system. The multiuser detection (MUD) and turbo coding are the two dominant techniques for enhancing the performance of the MC-CDMA systems in terms of BER as a solution of overcome to MAI effects. In this paper a low complexity iterative soft sensitive bits algorithm (SBA) aided logarithmic-Maximum a-Posteriori algorithm (Log MAP) based turbo MUD is proposed. Simulation results show that the proposed method provides better BER performance with low complexity decoding, by mitigating the detrimental effects of MAI.

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

    NASA Astrophysics Data System (ADS)

    Hortos, William S.

    1998-03-01

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

  16. A narrowband CDMA communications payload for little LEOS applications

    NASA Astrophysics Data System (ADS)

    Michalik, H.; Hävecker, W.; Ginati, A.

    1996-09-01

    In recent years Code Division Multiple Access (CDMA) techniques have been investigated for application in Local Area Networks [J. A. Salehi, IEEE Trans. Commun. 37 (1989)]as well as in Mobile Communications [R. Kohno et al., IEEE Commun. Mag. Jan (1995)]. The main attraction of these techniques is due to potential higher throughput and capacity of such systems under certain conditions compared to conventional multi-access schemes like frequency and time division multiplexing. Mobile communication over a Satellite Link represents in some terms the "worst case" for operating a CDMA-system. Considering e.g. the uplink case from mobile to satellite, the imperfections due to different and time varying channel conditions will add to the well known effects of Multiple Access Interference (MAI) between the simultaneously active users at the satellite receiver. In addition, bandwidth constraints due to the non-availability of large bandwidth channels in the interesting frequency bands, exist for small systems. As a result, for a given service in terms of user data rates, the practical code sequence lengths are limited as well as the available number of codes within a code set. In this paper a communications payload for Small Satellite Applications with CDMA uplink and C/TDMA downlink under the constraint of bandwidth limitations is proposed. To optimise the performance under the above addressed imperfections the system provides ability for power control and synchronisation for the CDMA uplink. The major objectives of this project are studying, development and testing of such a system for educational purposes and technology development at Hochschule Bremen.

  17. Deaf mobile application accessibility requirements

    NASA Astrophysics Data System (ADS)

    Nathan, Shelena Soosay; Hussain, Azham; Hashim, Nor Laily

    2016-08-01

    Requirement for deaf mobile applications need to be analysed to ensure the disabilities need are instilled into the mobile applications developed for them. Universal design is understandable to comply every user needs, however specific disability is argued by the authors to have different need and requirements. These differences are among the reasons for these applications being developed to target for a specific group of people, however they are less usable and later abandoned. This study focuses on deriving requirements that are needed by the deaf in their mobile applications that are meant specifically for them. Studies on previous literature was conducted it can be concluded that graphic, text, multimedia and sign language interpreter are among mostly required features to be included in their mobile application to ensure the applications are usable for this community.

  18. Accessibility: Maximum Mobility and Function.

    ERIC Educational Resources Information Center

    Smyser, Michael

    2003-01-01

    Describes how to design school and university labs to comply with Americans with Disabilities Act (ADA) standards, focusing on counter height for students in wheelchairs; appropriate knee space and sink height in sink areas; ADA-compliant fume hoods; accessible laboratory doors and entryways; and safety concerns (e.g., emergency eyewash stations…

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

    NASA Technical Reports Server (NTRS)

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

    1995-01-01

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

  20. Mobile App to Assess Universal Access Compliance.

    PubMed

    Fransolet, Colette

    2016-01-01

    In terms of local legislation, South Africa has a handful of regulations that indirectly require Universal Access, which is then in itself largely described as facilities for people with disabilities. The most predominant set of regulations is the South African National Building Regulations, with a specific code which is deemed to satisfy standard titled South African National Standard (SANS) 10400 Part S: Facilities for Persons with Disabilities. Revised in 2011, this building regulation offers some technical guidelines specific to built infrastructure, and largely for people with functional mobility limitations. The description of the term "functional mobility limitations" in the context of this paper refers to people who make use of mobility aids to assist with their functionality in an environment, for example people who use walking aids (sticks, canes or walkers) and people who use wheelchairs. Albeit lacking in specifics around the requirements for other areas of functional limitations, including people who are blind, people who are deaf, and people with cognitive limitations, the SANS 10400 Part S is, to date, the most effective regulatory requirement in the country to assist with making facilities more accessible. With only a few experts in South Africa working in the field, the ability to offer clients Universal Access Reviews in terms of basic compliance with the SANS 10400 Part S is limited by two major factors. Firstly, the costs associated with employing experts in the field to review infrastructure is mostly too exorbitant for clients to carry. Secondly, the amount of time taken to perform reviews onsite and then collate the information into a coherent report for the client is far too long. These aspects result in a gap between clients wanting to meet the requirements, and being able to have the work completed in a reasonable amount of time. To overcome the challenge of larger institutions and organizations wanting to have their facilities reviewed in

  1. 49 CFR 38.23 - Mobility aid accessibility.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 49 Transportation 1 2014-10-01 2014-10-01 false Mobility aid accessibility. 38.23 Section 38.23 Transportation Office of the Secretary of Transportation AMERICANS WITH DISABILITIES ACT (ADA) ACCESSIBILITY SPECIFICATIONS FOR TRANSPORTATION VEHICLES Buses, Vans and Systems § 38.23 Mobility aid accessibility....

  2. Performance of Improved Channel Allocation for Multicarrier CDMA with Adaptive Frequency Hopping and Multiuser Detection

    DTIC Science & Technology

    2008-08-29

    SECURITY CLASSIFICATION OF: Subchannel allocation for the reverse link of multicarrier code-division multiplex-access (MC-CDMA) system with adaptive...Triangle Park, NC 27709-2211 15. SUBJECT TERMS subchannel allocation, fading channels, CDMA Tao Jia, Alexandra Duel-Hallen North Carolina State University... Subchannel allocation for the reverse link of multicarrier code-division multiplex-access (MC-CDMA) system with adaptive frequency hopping (AFH) is

  3. Development of fiber-optic CDMA systems

    NASA Astrophysics Data System (ADS)

    Hassan, Kamel M.

    2005-09-01

    Fiber-Optic code division multiple access communication systems (FO-CDMA) have been given an intensifying interest in the last decade. This is due to several advantages may be offered by this technology, where it offers a promising solution for efficient truly asynchronous multiple access network as well as it has the ability to support variable bit rate and bursty traffic. FO-CDMA system permits an extra high optical signal processing speed compared to electronic signal processing, and there is no need to use wavelength sensitive components which are required in WDMA networks. FO-CDMA may be performed in time domain "t" or in wavelength domain "λ"(spectral amplitude encoding), this strategy is called one dimensional (1-D) optical coding. One of the most serious problems for CDMA is the multiple access interference (MAI), where it produces an asymptotic floor to the error probability, and limits the number of simultaneous users. Developing of FO-CDMA system to increase the number of users as well as to improve the system performance may be done through developing the system structure, choice of the appropriate detection scheme and the proper signature codes, developing the encoders and decoders hardware, use of adequate error correcting codes, incorporating optical amplifiers, use of multidimensional FO-CDMA techniques, and use of MAI cancellation and dispersion compensation techniques. This paper highlights the main directions of system development. The main technological challenges that have to be overcome before a wide spread of this technology have been also investigated. Finally, potential applications of this technology have been discussed.

  4. Preservice Teachers' Experiences on Accessing Course Materials Using Mobile Devices

    ERIC Educational Resources Information Center

    Unal, Zafer; Unal, Aslihan

    2014-01-01

    This study investigates and reports the first time experiences of mobile device users accessing the course materials on both the web and mobile version of course management system (Web Moodle & Mobile Moodle) during an online course offered at the University of South Florida, St. Petersburg College of Education.

  5. A secure network access system for mobile IPv6

    NASA Astrophysics Data System (ADS)

    Zhang, Hong; Yuan, Man; He, Rui; Jiang, Luliang; Ma, Jian; Qian, Hualin

    2004-03-01

    With the fast development of Internet and wireless and mobile communication technology, the Mobile Internet Age is upcoming. For those providing Mobile Internet services, especially from the view of ISP (Internet Service Provider), current mobile IP protocol is insufficient. Since the Mobile IPv6 protocol will be popular in near future, how to provide a secure mobile IPv6 service is important. A secure mobile IPv6 network access system is highly needed for mobile IPv6 deployment. Current methods and systems are still inadequate, including EAP, PANA, 802.1X, RADIUS, Diameter, etc. In this paper, we describe main security goals for a secure mobile IPv6 access system, and propose a secure network access system to achieve them. This access system consists of access router, attendant and authentication servers. The access procedure is divided into three phases, which are initial phase, authentication and registration phase and termination phase. This system has many advantages, including layer two independent, flexible and extensible, no need to modify current IPv6 address autoconfiguration protocols, binding update optimization, etc. Finally, the security of the protocol in this system is analyzed and proved with Extended BAN logic method, and a brief introduction of system implementation is given.

  6. The effects of simultaneous combined exposure to CDMA and WCDMA electromagnetic fields on rat testicular function.

    PubMed

    Lee, Hae-June; Jin, Yeung Bae; Kim, Tae-Hong; Pack, Jeong-Ki; Kim, Nam; Choi, Hyung-Do; Lee, Jae-Seon; Lee, Yun-Sil

    2012-05-01

    Wireless mobile phones and other telecommunication devices are used extensively in daily life. We therefore examined the effects of combined exposure to radiofrequency electromagnetic fields (RF-EMF) on rat testicular function, specifically with respect to sensitive processes such as spermatogenesis. Male rats were exposed to single code division multiple access (CDMA) and wideband code division multiple access (WCDMA) RF signals for 12 weeks. The RF exposure schedule comprised 45 min/day, 5 days/week for a total of 12 weeks. The whole-body average specific absorption rate (SAR) of CDMA and WCDMA was 2.0 W/kg each or 4.0 W/kg in total. We then investigated the correlates of testicular function such as sperm count in the cauda epididymis, testosterone concentration in the blood serum, malondialdehyde concentrations in the testes and epididymis, frequency of spermatogenesis stages, and appearance of apoptotic cells in the testes. We also immunoblotted for p53, bcl2, GADD45, cyclin G, and HSP70 in the testes of sham- and combined RF-exposed animals. Based on the results, we concluded that simultaneous exposure to CDMA and WCDMA RF-EMFs at 4.0 W/kg SAR did not have any observable adverse effects on rat spermatogenesis.

  7. 36 CFR 1192.125 - Mobility aid accessibility.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... Intercity Rail Cars and Systems § 1192.125 Mobility aid accessibility. (a)(1) General. All intercity rail cars, other than level entry cars, required to be accessible by § 1192.111 (a) and (e) of this subpart...(d) are provided, at stations or stops required to be accessible by 49 CFR part 37, the car is...

  8. 36 CFR 1192.125 - Mobility aid accessibility.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... Intercity Rail Cars and Systems § 1192.125 Mobility aid accessibility. (a)(1) General. All intercity rail cars, other than level entry cars, required to be accessible by § 1192.111 (a) and (e) of this subpart...(d) are provided, at stations or stops required to be accessible by 49 CFR part 37, the car is...

  9. Assured Access/Mobile Computing Initiatives on Five University Campuses.

    ERIC Educational Resources Information Center

    Blurton, Craig; Chee, Yam San; Long, Phillip D.; Resmer, Mark; Runde, Craig

    Mobile computing and assured access are becoming popular terms to describe a growing number of university programs which take advantage of ubiquitous network access points and the portability of notebook computers to ensure all students have access to digital tools and resources. However, the implementation of such programs varies widely from…

  10. A New Family of 2-D Optical Orthogonal Codes and Analysis of Its Performance in Optical CDMA Access Networks

    NASA Astrophysics Data System (ADS)

    Shurong, Sun; Yin, Hongxi; Wang, Ziyu; Xu, Anshi

    2006-04-01

    A new family of two-dimensional optical orthogonal code (2-D OOC), one-coincidence frequency hop code (OCFHC)/OOC, which employs OCFHC and OOC as wavelengthhopping and time-spreading patterns, respectively, is proposed in this paper. In contrary to previously constructed 2-D OOCs, OCFHC/OOC provides more choices on the number of available wavelengths and its cardinality achieves the upper bound in theory without sacrificing good auto-and-cross correlation properties, i.e., the correlation properties of the code is still ideal. Meanwhile, we utilize a new method, called effective normalized throughput, to compare the performance of diverse codes applicable to optical code division multiple access (OCDMA) systems besides conventional measure bit error rate, and the results indicate that our code performs better than obtained OCDMA codes and is truly applicable to OCDMA networks as multiaccess codes and will greatly facilitate the implementation of OCDMA access networks.

  11. 49 CFR 38.159 - Mobility aid accessibility.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... SPECIFICATIONS FOR TRANSPORTATION VEHICLES Over-the-Road Buses and Systems § 38.159 Mobility aid accessibility... by the Department of Transportation, the bus is not required to be equipped with a...

  12. New packet scheduling algorithm in wireless CDMA data networks

    NASA Astrophysics Data System (ADS)

    Wang, Yu; Gao, Zhuo; Li, Shaoqian; Li, Lemin

    2002-08-01

    The future 3G/4G wireless communication systems will provide internet access for mobile users. Packet scheduling algorithms are essential for QoS of diversified data traffics and efficient utilization of radio spectrum.This paper firstly presents a new packet scheduling algorithm DSTTF under the assumption of continuous transmission rates and scheduling intervals for CDMA data networks . Then considering the constraints of discrete transmission rates and fixed scheduling intervals imposed by the practical system, P-DSTTF, a modified version of DSTTF, is brought forward. Both scheduling algorithms take into consideration of channel condition, packet size and traffic delay bounds. The extensive simulation results demonstrate that the proposed scheduling algorithms are superior to some typical ones in current research. In addition, both static and dynamic wireless channel model of multi-level link capacity are established. These channel models sketch better the characterizations of wireless channel than two state Markov model widely adopted by the current literature.

  13. Channel coding for underwater acoustic single-carrier CDMA communication system

    NASA Astrophysics Data System (ADS)

    Liu, Lanjun; Zhang, Yonglei; Zhang, Pengcheng; Zhou, Lin; Niu, Jiong

    2017-01-01

    CDMA is an effective multiple access protocol for underwater acoustic networks, and channel coding can effectively reduce the bit error rate (BER) of the underwater acoustic communication system. For the requirements of underwater acoustic mobile networks based on CDMA, an underwater acoustic single-carrier CDMA communication system (UWA/SCCDMA) based on the direct-sequence spread spectrum is proposed, and its channel coding scheme is studied based on convolution, RA, Turbo and LDPC coding respectively. The implementation steps of the Viterbi algorithm of convolutional coding, BP and minimum sum algorithms of RA coding, Log-MAP and SOVA algorithms of Turbo coding, and sum-product algorithm of LDPC coding are given. An UWA/SCCDMA simulation system based on Matlab is designed. Simulation results show that the UWA/SCCDMA based on RA, Turbo and LDPC coding have good performance such that the communication BER is all less than 10-6 in the underwater acoustic channel with low signal to noise ratio (SNR) from -12 dB to -10dB, which is about 2 orders of magnitude lower than that of the convolutional coding. The system based on Turbo coding with Log-MAP algorithm has the best performance.

  14. Accessible Microscopy Workstation for Students and Scientists with Mobility Impairments

    ERIC Educational Resources Information Center

    Duerstock, Bradley S.

    2006-01-01

    An integrated accessible microscopy workstation was designed and developed to allow persons with mobility impairments to control all aspects of light microscopy with minimal human assistance. This system, named AccessScope, is capable of performing brightfield and fluorescence microscopy, image analysis, and tissue morphometry requisite for…

  15. Delay and throughput characteristics of TH, CDMA, TDMA, and hybrid networks for multipath faded data transmission channels

    NASA Astrophysics Data System (ADS)

    Elhakeem, Ahmed K.; Digirolamo, Rocco; Bdira, Ilyess B.; Talla, M.

    1994-05-01

    The new concepts of adaptive time hopping and variable frame Code Division (CDMA) Multiple Access are introduced. By a unified analysis, the probabilities of bit and packet errors in multipath fading environment for five Time Division (TDMA), Code Division, and Time Hopping (TH) related multiaccess networks are obtained; namely, TDMA, CDMA, CDMA/TDMA, Adaptive CDMA/TH, and variable frame CDMA/TDMA networks. The delay and useful throughputs of the five systems are also evaluated for data and voice traffic. All systems compared have the same channel power and bandwidth and support the same traffic. Though implementation issues are not covered, CDMA systems are put at a disadvantage (compared to cellular-type FDMA networks, for example) by ignoring such inherent advantages as voice silence utilizations and automatic frequency reuse. Nonetheless, two CDMA systems outperform TDMA systems at low and medium input traffics.

  16. Mobile access to the Internet: from personal bubble to satellites

    NASA Astrophysics Data System (ADS)

    Gerla, Mario

    2001-10-01

    Mobile, wireless access and networking has emerged in the last few years as one of the most important directions of Internet growth. The popularity of mobile, and, more generally, nomadic Internet access is due to many enabling factors including: (a) emergence of meaningful applications tailored to the individual on the move; (b) small form factor and long battery life; (c) efficient middleware designed to support mobility; and, (d) efficient wireless networking technologies. A key player in the mobile Internet access is the nomad, i.e. the individual equipped with various computing and I/O gadgets (cellular phone, earphones, GPS navigator, palm pilot, beeper, portable scanner, digital camera, etc.). These devices form his/her Personal Area Network or PAN or personal bubble. The connectivity within the bubble is wireless (using for example a low cost, low power wireless LAN such as Bluetooth). The bubble can expand and contract dynamically depending on needs. It may temporarily include sensors and actuators as the nomad walks into a new environment. In this paper, we identify the need for the interconnection of the PAN with other wireless networks in order to achieve costeffective mobile access to the Internet. We will overview some key networking technologies required to support the PAN (eg, Bluetooth). We will also discuss an emerging technology, Ad Hoc wireless networking which is the natural complement of the PAN in sparsely populated areas. Finally, we will identify the need for intelligent routers to assist the mobile user in the selection of the best Internet access strategy.

  17. Impairments Computation for Routing Purposes in a Transparent-Access Optical Network Based on Optical CDMA and WDM

    NASA Astrophysics Data System (ADS)

    Musa, Ahmed

    2016-06-01

    Optical access networks are becoming more widespread and the use of multiple services might require a transparent optical network (TON). Multiplexing and privacy could benefit from the combination of wavelength division multiplexing (WDM) and optical coding (OC) and wavelength conversion in optical switches. The routing process needs to be cognizant of different resource types and characteristics such as fiber types, fiber linear impairments such as attenuation, dispersion, etc. as well as fiber nonlinear impairments such as four-wave mixing, cross-phase modulation, etc. Other types of impairments, generated by optical nodes or photonic switches, also affect the signal quality (Q) or the optical signal to noise ratio (OSNR), which is related to the bit error rate (BER). Therefore, both link and switch impairments must be addressed and somehow incorporated into the routing algorithm. However, it is not practical to fully integrate all photonic-specific attributes in the routing process. In this study, new routing parameters and constraints are defined that reflect the distinct characteristics of photonic networking. These constraints are applied to the design phase of TON and expressed as a cost or metric form that will be used in the network routing algorithm.

  18. Accessing multimedia content from mobile applications using semantic web technologies

    NASA Astrophysics Data System (ADS)

    Kreutel, Jörn; Gerlach, Andrea; Klekamp, Stefanie; Schulz, Kristin

    2014-02-01

    We describe the ideas and results of an applied research project that aims at leveraging the expressive power of semantic web technologies as a server-side backend for mobile applications that provide access to location and multimedia data and allow for a rich user experience in mobile scenarios, ranging from city and museum guides to multimedia enhancements of any kind of narrative content, including e-book applications. In particular, we will outline a reusable software architecture for both server-side functionality and native mobile platforms that is aimed at significantly decreasing the effort required for developing particular applications of that kind.

  19. Accessible microscopy workstation for students and scientists with mobility impairments.

    PubMed

    Duerstock, Bradley S

    2006-01-01

    An integrated accessible microscopy workstation was designed and developed to allow persons with mobility impairments to control all aspects of light microscopy with minimal human assistance. This system, named AccessScope, is capable of performing brightfield and fluorescence microscopy, image analysis, and tissue morphometry requisite for undergraduate science courses to graduate-level research. An accessible microscope is necessary for students and scientists with mobility impairments to be able to use a microscope independently to better understand microscopical imaging concepts and cell biology. This knowledge is not always apparent by simply viewing a catalog of histological images. The ability to operate a microscope independently eliminates the need to hire an assistant or rely on a classmate and permits one to take practical laboratory examinations by oneself. Independent microscope handling is also crucial for graduate students and scientists with disabilities to perform scientific research. By making a personal computer as the user interface for controlling AccessScope functions, different upper limb mobility impairments could be accommodated by using various computer input devices and assistive technology software. Participants with a range of upper limb mobility impairments evaluated the prototype microscopy workstation. They were able to control all microscopy functions including loading different slides without assistance.

  20. 36 CFR 1192.95 - Mobility aid accessibility.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... mechanical, electrical or other system operates to ensure that cars do not move when the lift is in use. (3... Commuter Rail Cars and Systems § 1192.95 Mobility aid accessibility. (a)(1) General. All new commuter rail cars, other than level entry cars, covered by this subpart shall provide a level-change mechanism...

  1. 36 CFR 1192.95 - Mobility aid accessibility.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... mechanical, electrical or other system operates to ensure that cars do not move when the lift is in use. (3... Commuter Rail Cars and Systems § 1192.95 Mobility aid accessibility. (a)(1) General. All new commuter rail cars, other than level entry cars, covered by this subpart shall provide a level-change mechanism...

  2. Homeless Families' Education Networks: An Examination of Access and Mobilization

    ERIC Educational Resources Information Center

    Miller, Peter M.

    2011-01-01

    Purpose: This study sought deeper understanding of how sheltered families accessed and mobilized educationally related relationships and resources during periods of homelessness. Such work is posited to be especially relevant considering that there is a growing crisis of family homelessness in the United States and school- and community-based…

  3. Autonomy and Housing Accessibility Among Powered Mobility Device Users

    PubMed Central

    Brandt, Åse; Lexell, Eva Månsson; Iwarsson, Susanne

    2015-01-01

    OBJECTIVE. To describe environmental barriers, accessibility problems, and powered mobility device (PMD) users’ autonomy indoors and outdoors; to determine the home environmental barriers that generated the most housing accessibility problems indoors, at entrances, and in the close exterior surroundings; and to examine personal factors and environmental components and their association with indoor and outdoor autonomy. METHOD. This cross-sectional study was based on data collected from a sample of 48 PMD users with a spinal cord injury (SCI) using the Impact of Participation and Autonomy and the Housing Enabler instruments. Descriptive statistics and logistic regression were used. RESULTS. More years living with SCI predicted less restriction in autonomy indoors, whereas more functional limitations and accessibility problems related to entrance doors predicted more restriction in autonomy outdoors. CONCLUSION. To enable optimized PMD use, practitioners must pay attention to the relationship between client autonomy and housing accessibility problems. PMID:26356666

  4. Radio resource management for CDMA systems with interference guard margin (IGM)

    NASA Astrophysics Data System (ADS)

    Chen, Huan; Kumar, Sunil; Kuo, C.-C. Jay

    2001-11-01

    A call admission control (CAC) scheme and a resource reservation estimation (RRE) method suitable for the wide-band code division multiple access (W-CDMA) systems are proposed in this work. The proposed CAC scheme gives preferential treatment to high priority calls, such as handoff calls, by pre-reserving a certain amount of channel margin against the interference effect. It is called the interference guard margin (IGM) scheme. The amount of guard margin is determined by the measurement performed by the RRE module in base stations. Each RRE module dynamically adjusts the level of guard margin by referencing traffic conditions in neighboring cells based upon users' requests. A comprehensive service model is adopted to accommodate the scenario of multiple services supported in the W-CDMA system. The service model of consideration includes not only mobile terminal's service rate (source rate) but also different levels of priorities, mobility and rate adaptivity characteristics. Simulations are conducted with OPNET to study the performance of the proposed scheme in term of the objective function under different traffic conditions.

  5. Call admission control for CDMA systems with Interference Guard Margin (IGM)

    NASA Astrophysics Data System (ADS)

    Chen, Huan; Kumar, Sunil; Kuo, C.-C. Jay

    2002-01-01

    A call admission control (CAC) scheme and a resource-reservation estimation (RRE) method suitable for the interference-based wireless system, such as wide-band code division multiple access (W-CDMA), are proposed in this work. The proposed CAC scheme gives preferential treatment to high priority handoff calls by pre-reserving a certain amount of interference margin called the interference guard margin (IGM). The amount of guard margin is determined by the measurement performed by the RRE module in base stations. Each RRE module dynamically adjusts the level of guard margin by considering traffic conditions in neighboring cells based upon handoff requests. A service model is adopted to support multiple services, which includes mobile terminal's data rate, different levels of priorities, mobility and rate adaptivity characteristics. Simulations are conducted with OPNET to study the performance of the proposed scheme in terms of the objective function, blocking probabilities and system utilization under different traffic conditions.

  6. DS-CDMA satellite diversity reception for personal satellite communication: Downlink performance analysis

    NASA Technical Reports Server (NTRS)

    DeGaudenzi, Riccardo; Giannetti, Filippo

    1995-01-01

    The downlink of a satellite-mobile personal communication system employing power-controlled Direct Sequence Code Division Multiple Access (DS-CDMA) and exploiting satellite-diversity is analyzed and its performance compared with a more traditional communication system utilizing single satellite reception. The analytical model developed has been thoroughly validated by means of extensive Monte Carlo computer simulations. It is shown how the capacity gain provided by diversity reception shrinks considerably in the presence of increasing traffic or in the case of light shadowing conditions. Moreover, the quantitative results tend to indicate that to combat system capacity reduction due to intra-system interference, no more than two satellites shall be active over the same region. To achieve higher system capacity, differently from terrestrial cellular systems, Multi-User Detection (MUD) techniques are likely to be required in the mobile user terminal, thus considerably increasing its complexity.

  7. A Link-Level Simulator of the cdma2000 Reverse-Link Physical Layer

    PubMed Central

    Gharavi, H.; Chin, F.; Ban, K.; Wyatt-Millington, R.

    2003-01-01

    The cdma2000 system is an evolutionary enhancement of the IS-95 standards which support 3G services defined by the International Telecommunications Union (ITU). cdma2000 comes in two phases: 1XRTT and 3XRTT (1X and 3X indicates the number of 1.25 MHz wide radio carrier channels used and RTT stands for Radio Transmission Technology). The cdma2000 1XRTT, which operates within a 1.25 MHz bandwidth, can be utilized in existing IS-95 CDMA channels as it uses the same bandwidth, while 3XRTT requires the commitment of 5 MHz bandwidth to support higher data rates. This paper describes a software model implementation of the cdma2000 reverse link and its application for evaluating the effect of rake receiver design parameters on the system performance under various multipath fading conditions. The cdma2000 models were developed at the National Institute of Standards and Technology (NIST), using SPW (Signal Processing Worksystem) commercial software tools. The model has been developed in a generic manner that includes all the reverse link six radio configurations and their corresponding data rates, according to cdma2000 specifications. After briefly reviewing the traffic channel characteristics of the cdma2000 reverse link (subscriber to base station), the paper discusses the rake receiver implementation including an ideal rake receiver. It then evaluates the performance of each receiver for a Spreading Rate 3 (3XRTT) operation, which is considered as a true “3G” cdma2000 technology. These evaluations are based on the vehicular IMT-2000 (International Mobile Telecommunication 2000) channel model using the link budget defined in cdma2000 specifications for the reverse link. PMID:27413613

  8. A Link-Level Simulator of the cdma2000 Reverse-Link Physical Layer.

    PubMed

    Gharavi, H; Chin, F; Ban, K; Wyatt-Millington, R

    2003-01-01

    The cdma2000 system is an evolutionary enhancement of the IS-95 standards which support 3G services defined by the International Telecommunications Union (ITU). cdma2000 comes in two phases: 1XRTT and 3XRTT (1X and 3X indicates the number of 1.25 MHz wide radio carrier channels used and RTT stands for Radio Transmission Technology). The cdma2000 1XRTT, which operates within a 1.25 MHz bandwidth, can be utilized in existing IS-95 CDMA channels as it uses the same bandwidth, while 3XRTT requires the commitment of 5 MHz bandwidth to support higher data rates. This paper describes a software model implementation of the cdma2000 reverse link and its application for evaluating the effect of rake receiver design parameters on the system performance under various multipath fading conditions. The cdma2000 models were developed at the National Institute of Standards and Technology (NIST), using SPW (Signal Processing Worksystem) commercial software tools. The model has been developed in a generic manner that includes all the reverse link six radio configurations and their corresponding data rates, according to cdma2000 specifications. After briefly reviewing the traffic channel characteristics of the cdma2000 reverse link (subscriber to base station), the paper discusses the rake receiver implementation including an ideal rake receiver. It then evaluates the performance of each receiver for a Spreading Rate 3 (3XRTT) operation, which is considered as a true "3G" cdma2000 technology. These evaluations are based on the vehicular IMT-2000 (International Mobile Telecommunication 2000) channel model using the link budget defined in cdma2000 specifications for the reverse link.

  9. Diversity reception for advanced multi-satellite networks: A CDMA approach

    NASA Technical Reports Server (NTRS)

    Colzi, E.; Degaudenzi, R.; Elia, C.; Giannetti, F.; Viola, R.

    1993-01-01

    Diversity reception for Synchronous CDMA (S-CDMA) is introduced and analyzed. A Gaussian co-channel synchronous and asynchronous interference approximation is derived to evaluate the effects on the system bit error rate. Numerical results are provided for a simple mobile communication system where the signals transmitted by two distinct satellites in visibility are coherently combined by a three fingers Rake receiver. A second example showing performance of an integrated ground/satellite single frequency network for digital audio broadcasting is presented. Results show the capacity advantage of utilizing S-CDMA in combination with diversity reception.

  10. Fast frequency hopping codes applied to SAC optical CDMA network

    NASA Astrophysics Data System (ADS)

    Tseng, Shin-Pin

    2015-06-01

    This study designed a fast frequency hopping (FFH) code family suitable for application in spectral-amplitude-coding (SAC) optical code-division multiple-access (CDMA) networks. The FFH code family can effectively suppress the effects of multiuser interference and had its origin in the frequency hopping code family. Additional codes were developed as secure codewords for enhancing the security of the network. In considering the system cost and flexibility, simple optical encoders/decoders using fiber Bragg gratings (FBGs) and a set of optical securers using two arrayed-waveguide grating (AWG) demultiplexers (DeMUXs) were also constructed. Based on a Gaussian approximation, expressions for evaluating the bit error rate (BER) and spectral efficiency (SE) of SAC optical CDMA networks are presented. The results indicated that the proposed SAC optical CDMA network exhibited favorable performance.

  11. Demonstration of Record BER and Number of Users for Optical CDMA (O-CDMA), with Implications to Secure Communications

    SciTech Connect

    Mendez, A J; Hernandez, V J; Bennett, C V; Gagliardi, R M; Lennon, W J

    2005-02-25

    We demonstrate a BER of 10{sup -11} for 16 simultaneous users, using wavelength/time O-CDMA. We show the extent to which severe multi-access interference can be used to mask and/or degrade the signal from an intruder.

  12. Mobile satellite business networks: A part of the European mobile system

    NASA Technical Reports Server (NTRS)

    deMateo, M. L.; Jongejans, A.; Loisy, C.; VanHimbeeck, C.; Marchal, J. P.; Borella, A.; Sartori, M.

    1995-01-01

    The European Space Agency (ESA) is presently procuring an L-band payload EMS, to be embarked on the ITALSAT-2 satellite due for launch in early 1996, in order to promote a regional European mobile system. One of the Land Mobile Communication systems supported by EMS is the MSBN (Mobile Satellite Business Network) voice and data system which will offer the services of a business network on a seamless European coverage. This paper will first recall the characteristics of the MSBN system, which is based on quasi-synchronized CDMA (Code Division Multiple Access) techniques in both directions, and then describe the CDMA receivers implementation. Main validation test results will also be reported confirming predicted performances.

  13. Effects of 1950 MHz W-CDMA-like signal on human spermatozoa.

    PubMed

    Nakatani-Enomoto, Setsu; Okutsu, Miho; Suzuki, Satoshi; Suganuma, Ryota; Groiss, Stefan Jun; Kadowaki, Suguru; Enomoto, Hiroyuki; Fujimori, Keiya; Ugawa, Yoshikazu

    2016-09-01

    There are growing concerns about how electromagnetic waves (EMW) emitted from mobile phones affect human spermatozoa. Several experiments have suggested harmful effects of EMW on human sperm quality, motility, velocity, or the deoxyribonucleic acid (DNA) of spermatozoa. In this study, we analyzed the effects on human spermatozoa (sperm motility and kinetic variables) induced by 1 h of exposure to 1950 MHz Wideband Code Division Multiple Access (W-CDMA)-like EMW with specific absorption rates of either 2.0 or 6.0 W/kg, using a computer-assisted sperm analyzer system. We also measured the percentage of 8-hydroxy-2'-deoxyguanosine (8-OHdG) positive spermatozoa with flow cytometry to evaluate damage to DNA. No significant differences were observed between the EMW exposure and the sham exposure in sperm motility, kinetic variables, or 8-OHdG levels. We conclude that W-CDMA-like exposure for 1 h under temperature-controlled conditions has no detectable effect on normal human spermatozoa. Differences in exposure conditions, humidity, temperature control, baseline sperm characteristics, and age of donors may explain inconsistency of our results with several previous studies. Bioelectromagnetics. 37:373-381, 2016. © 2016 Wiley Periodicals, Inc.

  14. Use of Mobile Devices to Access Resources Among Health Professions Students: A Systematic Review.

    PubMed

    Mi, Misa; Wu, Wendy; Qiu, Maylene; Zhang, Yingting; Wu, Lin; Li, Jie

    2016-01-01

    This systematic review examines types of mobile devices used by health professions students, kinds of resources and tools accessed via mobile devices, and reasons for using the devices to access the resources and tools. The review included 20 studies selected from articles published in English between January 2010 and April 2015, retrieved from PubMed and other sources. Data extracted included participants, study designs, mobile devices used, mobile resources/apps accessed, outcome measures, and advantages of and barriers to using mobile devices. The review indicates significant variability across the studies in terms of research methods, types of mobile programs implemented, resources accessed, and outcomes. There were beneficial effects of using mobile devices to access resources as well as conspicuous challenges or barriers in using mobile devices.

  15. Resolving mobility constraints impeding rural seniors' access to regionalized services.

    PubMed

    Ryser, Laura; Halseth, Greg

    2012-01-01

    Rural and small town places in developed economies are aging. While attention has been paid to the local transportation needs of rural seniors, fewer researchers have explored their regional transportation needs. This is important given policies that have reduced and regionalized many services and supports. This article explores mobility constraints impeding rural seniors' access to regionalized services using the example of northern British Columbia. Drawing upon several qualitative studies, we explore geographical, maintenance, organizational, communication, human resources, infrastructure, and financial constraints that affect seniors' regional mobility. Our findings indicate that greater coordination across multiple government agencies and jurisdictions is needed and more supportive policies and resources must be in place to facilitate a comprehensive regional transportation strategy. In addition to discussing the complexities of these geographies, the article identifies innovative solutions that have been deployed in northern British Columbia to support an aging population. This research provides a foundation for developing a comprehensive understanding of the key issues that need to be addressed to inform strategic investments in infrastructure and programs that support the regional mobility and, hence, healthy aging of rural seniors.

  16. Design of a Virtual Quadrant Receiver for 4-ary Pulse Position Modulation/Optical CDMA (4-ary PPM/O-CDMA)

    SciTech Connect

    Mendez, A J; Gagliardi, R M; Hernandez, V J; Bennett, C V; Lennon, W J

    2006-07-03

    We describe a receiver that performs optical code division multiple access (O-CDMA) decoding followed by pulse position modulation (PPM) symbol detection that behaves like a radar quadrant receiver. Simulations determine the impact of multi-access interference on symbol detection for up to 32 users.

  17. An effective access control approach to support mobility in IPv6 networks

    NASA Astrophysics Data System (ADS)

    Peng, Xue-hai; Lin, Chuang

    2005-11-01

    Access control is an important method to improve network security and prevent protected resources from being used by some nodes without authority. Moreover, mobility is an important trend of internet. In this paper, based on the architecture of hierarchical mobile IPv6, we proposed an effective access control approach to support mobility in IPv6 networks, which can ensure the operation of access control when a mobile node roams in these domains with different polices, with decreased delay of access negotiation and cost of delivering messages.

  18. Data communications with VSATs - RA/TDMA vs. SS/CDMA

    NASA Astrophysics Data System (ADS)

    Kim, Kap S.

    Random-access TDMA and spread-spectrum CDMA, two of the most predominant hub-VSAT (very-small-aperture terminal) inbound access techniques today, are discussed in relation to the interactive data application environment where the response time is the most critical performance parameter. The system access techniques, access time, channel capacity, and performance comparison are presented. It is concluded that, in general, either RA/TDMA or SS/CDMA can provide cost/performance-effective serivce for interactive applications as compared with terrestrial service alternatives. If the user's data application consists mostly of short message transactions and its inbound aggregated data rate is low (less than 9.6 kb/s), the SS/CDMA system is recommended. The RA/TDMA system is better suited for the user applications which require a mix of interactive and batch processings.

  19. A WDM/Optical-CDMA (WDM/O-CDMA) Concept for Avionics Integration

    SciTech Connect

    Mendez, A J; Hernandez, V J; Gagliardi, R M; Braun, S W; Bennett, C V; Lennon, W J

    2005-06-02

    We describe a concept where WDM and O-CDMA share a set of discrete wavelengths and components while using similar modulation formats. O-CDMA acts as a channel multiplier. Experiments show the feasibility of >2X channel multiplication.

  20. Security Concerns in Accessing Naval e-Learning with Personal Mobile Devices

    DTIC Science & Technology

    2014-12-01

    IN ACCESSING NAVAL e - LEARNING WITH PERSONAL MOBILE DEVICES by Keystella R. Mitchell December 2014 Thesis Co-Advisors: Man-Tak Shing...December 2014 3. REPORT TYPE AND DATES COVERED Master’s Thesis 4. TITLE AND SUBTITLE SECURITY CONCERNS IN ACCESSING NAVAL e - LEARNING WITH PERSONAL...was to investigate the feasibility of using personal mobile devices for Naval e - Learning (NeL). Another objective was to find out which mobile device

  1. Adaptive mobile access protocol (AMAP) for the message service of a land mobile satellite experiment (MSAT-X)

    NASA Technical Reports Server (NTRS)

    Li, V. O. K.; Yan, T.-Y.

    1984-01-01

    This paper describes a feasibility study of the adaptive mobile access protocol (AMAP) for MSATA-X, a proposed experimental mobile satellite communication network. The mobiles are dispersed over a wide geographical area and the channel data rate is limited due to the size and cost limitations of mobile antennas. AMAP is a reservation based multiple-access scheme. The available bandwidth is divided into subchannels, which are divided into reservation and message channels. The ALOHA multiple-access scheme is employed in the reservation channels, while the message channels are demand assigned. AMAP adaptively reallocates the reservation and message channels to optimize system performance. It has been shown that if messages are generated at a rate of one message per hour, AMAP can support approximately 2000 active users per 2400 bit/s channel with an average delay of 1.4 s.

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

    NASA Technical Reports Server (NTRS)

    Arcidiancono, Antonio

    1990-01-01

    A survey is given of several approaches to improving the performance and marketability of mobile satellite systems (MSS). The provision of voice/data services in the future regional European Land Mobile Satellite System (LMSS), network integration between the Digital Cellular Mobile System (GSM) and LMSS, the identification of critical areas for the implementation of integrated GSM/LMSS areas, space segment scenarios, LMSS for digital trunked private mobile radio (PMR) services, and code division multiple access (CDMA) techniques for a terrestrial/satellite system are covered.

  3. Future mobile access for open-data platforms and the BBC-DaaS system

    NASA Astrophysics Data System (ADS)

    Edlich, Stefan; Singh, Sonam; Pfennigstorf, Ingo

    2013-03-01

    In this paper, we develop an open data platform on multimedia devices to act as marketplace of data for information seekers and data providers. We explore the important aspects of Data-as-a-Service (DaaS) service in the cloud with a mobile access point. The basis of the DaaS service is to act as a marketplace for information, utilizing new technologies and recent new scalable polyglot architectures based on NoSql databases. Whereas Open-Data platforms are beginning to be widely accepted, its mobile use is not. We compare similar products, their approach and a possible mobile usage. We discuss several approaches to address the mobile access as a native app, html5 and a mobile first approach together with the several frontend presentation techniques. Big data visualization itself is in the early days and we explore some possibilities to get big data / open data accessed by mobile users.

  4. Intercarrier Interference Reduction in MC-CDMA System through Second Order Duobinary Coded Phase Rotated Conjugate Cancellation Scheme

    PubMed Central

    Chitra, S.; Kumaratharan, N.

    2015-01-01

    Multi-carrier code division multiple access (MC-CDMA) technique is one of the strong candidates for next generation wireless mobile communication systems. Multi-carrier systems are very much sensitive to carrier frequency offset (CFO) results in intercarrier interference (ICI). To mitigate ICI without any spectral loss, a second order duobinary coded phase rotated conjugate cancellation algorithm is proposed in this paper. In the conventional phase rotated conjugate cancellation (PRCC) technique, one path carries the MC-CDMA signal with a phase spin of ϕ and the other path carries the conjugate of the first path signal with -ϕ phase spin. This artificial phase rotation allows the transmitter to tune the transmitted signals so that the ICI effects could be mutually cancelled at the receiver. Although the PRCC technique reduces the spectral efficiency, the limitation can be overcome by the joint second order duobinary coding scheme with PRCC technique. In the proposed method, the correlative coding between the binary symbols modulated on adjacent subcarriers is used to reduce the ICI without any spectral loss. Simulation results show that the proposed PRCC method provides better carrier to interference ratio (CIR) and bit error rate (BER) performances compared to the conventional conjugate cancellation (CC) technique. PMID:25790029

  5. Accessibility and mobility of lysine residues in. beta. -lactoglobulin

    SciTech Connect

    Brown, E.M.; Pfeffer, P.E.; Kumosinski, T.F.; Greenberg, R.

    1988-07-26

    N/sup epsilon/-(/sup 2/H/sub 6/)Isopropyllysyl-..beta..-lactoglobulin was prepared by reductive alkylation of ..beta..-lactoglobulin with (/sup 2/H/sub 6/)acetone and NaBH/sub 4/ to provide a /sup 2/H (NMR) probe for the study of lysine involvement in lipid-protein interactions. Amino acid analysis showed 80% of the protein's 15 lysine residues to be labeled. Unmodified lysine residues were located through peptide maps produced from CNBr, tryptic, and chymotryptic digests of the labeled protein. Average correlation times calculated from /sup 2/H NMR spectra were 20 and 320 ps for 8.7 and 3.3 residues, respectively, in 6 M guanidine hydrochloride; in nondenaturing solution, values of 70 and 320 ps were obtained for 6.5 and 3.2 residues, respectively, with the remaining 2.3 modified residues not observed, suggesting that side chains of lysine residues in unordered or flexible regions were more mobile than those in stable periodic structures. /sup 2/H NMR spectra of the protein complexed with dipalmitoylphosphatidylcholine confirmed the extrinsic membrane protein type behavior of ..beta..-lactoglobulin previously reported from /sup 31/P NMR studies of the phospholipids complexed with ..beta..-lactoglobulin. Although no physiological function has yet been identified, comparison of these results with the X-ray structure supports the hypothesis that residues not accessible for modification may help to stabilize the cone-shaped ..beta..-barrel thought to contain binding sites for small lipid-soluble molecules.

  6. Molecular mobility with respect to accessible volume in Monte Carlo lattice model for polymers

    NASA Astrophysics Data System (ADS)

    Diani, J.; Gilormini, P.

    2017-02-01

    A three-dimensional cubic Monte Carlo lattice model is considered to test the impact of volume on the molecular mobility of amorphous polymers. Assuming classic polymer chain dynamics, the concept of locked volume limiting the accessible volume around the polymer chains is introduced. The polymer mobility is assessed by its ability to explore the entire lattice thanks to reptation motions. When recording the polymer mobility with respect to the lattice accessible volume, a sharp mobility transition is observed as witnessed during glass transition. The model ability to reproduce known actual trends in terms of glass transition with respect to material parameters, is also tested.

  7. A performance analysis of DS-CDMA and SCPC VSAT networks

    NASA Technical Reports Server (NTRS)

    Hayes, David P.; Ha, Tri T.

    1990-01-01

    Spread-spectrum and single-channel-per-carrier (SCPC) transmission techniques work well in very small aperture terminal (VSAT) networks for multiple-access purposes while allowing the earth station antennas to remain small. Direct-sequence code-division multiple-access (DS-CDMA) is the simplest spread-spectrum technique to use in a VSAT network since a frequency synthesizer is not required for each terminal. An examination is made of the DS-CDMA and SCPC Ku-band VSAT satellite systems for low-density (64-kb/s or less) communications. A method for improving the standardf link analysis of DS-CDMA satellite-switched networks by including certain losses is developed. The performance of 50-channel full mesh and star network architectures is analyzed. The selection of operating conditions producing optimum performance is demonstrated.

  8. 47 CFR 64.402 - Policies and procedures for the provision of priority access service by commercial mobile radio...

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... priority access service by commercial mobile radio service providers. 64.402 Section 64.402... Policies and procedures for the provision of priority access service by commercial mobile radio service providers. Commercial mobile radio service providers that elect to provide priority access service...

  9. Quadriphase DS-CDMA wireless communication systems employing the generalized detector

    NASA Astrophysics Data System (ADS)

    Tuzlukov, Vyacheslav

    2012-05-01

    Probability of bit-error Per performance of asynchronous direct-sequence code-division multiple-access (DS-CDMA) wireless communication systems employing the generalized detector (GD) constructed based on the generalized approach to signal processing in noise is analyzed. The effects of pulse shaping, quadriphase or direct sequence quadriphase shift keying (DS-QPSK) spreading, aperiodic spreading sequences are considered in DS-CDMA based on GD and compared with the coherent Neyman-Pearson receiver. An exact Per expression and several approximations: one using the characterristic function method, a simplified expression for the improved Gaussian approximation (IGA) and the simplified improved Gaussian approximation are derived. Under conditions typically satisfied in practice and even with a small number of interferers, the standard Gaussian approximation (SGA) for the multiple-access interference component of the GD statistic and Per performance is shown to be accurate. Moreover, the IGA is shown to reduce to the SGA for pulses with zero excess bandwidth. Second, the GD Per performance of quadriphase DS-CDMA is shown to be superior to that of bi-phase DS-CDMA. Numerical examples by Monte Carlo simulation are presented to illustrate the GD Per performance for square-root raised-cosine pulses and spreading factors of moderate to large values. Also, a superiority of GD employment in CDMA systems over the Neyman-Pearson receiver is demonstrated

  10. 49 CFR 38.23 - Mobility aid accessibility.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ...) Seat belt and shoulder harness. For each wheelchair or mobility aid securement device provided, a passenger seat belt and shoulder harness, complying with all applicable provisions of part 571 of this title, shall also be provided for use by wheelchair or mobility aid users. Such seat belts and...

  11. Dispersion Compensation Requirements for Optical CDMA Using WDM Lasers

    SciTech Connect

    Mendez, A J; Hendandez, V J; Feng, H X C; Heritage, J P; Lennon, W J

    2001-12-10

    Optical code division multiple access (O-CDMA) uses very narrow transmission pulses and is thus susceptible to fiber optic link impairments. When the O-CDMA is implemented as wavelength/time (W/T) matrices which use wavelength division multiplexing (WDM) sources such as multi-frequency laser transmitters, the susceptibility may be higher due to: (a) the large bandwidth utilized and (b) the requirement that the various wavelength components of the codes be synchronized at the point of modulation and encoding as well as after (optical) correlation. A computer simulation based on the nonlinear Schroedinger equation, developed to study optical networking on the National Transparent Optical Network (NTON), was modified to characterize the impairments on the propagation and decoding of W/T matrix codes over a link of the NTON. Three critical link impairments were identified by the simulation: group velocity dispersion (GVD); the flatness of the optical amplifier gain; and the slope of the GVD. Subsequently, experiments were carried out on the NTON link to verify and refine the simulations as well as to suggest improvements in the W/T matrix signal processing design. The NTON link measurements quantified the O-CDMA dispersion compensation requirements. Dispersion compensation management is essential to assure the performance of W/T matrix codes.

  12. Concept and implementation of the Globalstar mobile satellite system

    NASA Technical Reports Server (NTRS)

    Schindall, Joel

    1995-01-01

    Globalstar is a satellite-based mobile communications system which provides quality wireless communications (voice and/or data) anywhere in the world except the polar regions. The Globalstar system concept is based upon technological advancements in Low Earth Orbit (LEO) satellite technology and in cellular telephone technology, including the commercial application of Code Division Multiple Access (CDMA) technologies. The Globalstar system uses elements of CDMA and Frequency Division Multiple Access (FDMA), combined with satellite Multiple Beam Antenna (MBA) technology and advanced variable-rate vocoder technology to arrive at one of the most efficient modulation and multiple access systems ever proposed for a satellite communications system. The technology used in Globalstar includes the following techniques in obtaining high spectral efficiency and affordable cost per channel: (1) CDMA modulation with efficient power control; (2) high efficiency vocoder with voice activity factor; (3) spot beam antenna for increased gain and frequency reuse; (4) weighted satellite antenna gain for broad geographic coverage; (5) multisatellite user links (diversity) to enhance communications reliability; and (6) soft hand-off between beams and satellites. Initial launch is scheduled in 1997 and the system is scheduled to be operational in 1998. The Globalstar system utilizes frequencies in L-, S- and C-bands which have the potential to offer worldwide availability with authorization by the appropriate regulatory agencies.

  13. Mobile Access to Libraries: Librarians and Users Experience for "I-Mode" Applications in Libraries.

    ERIC Educational Resources Information Center

    Negishi, Masamitsu

    Recent penetration of the Internet in every aspect of society is remarkable. Along with various types of access methods being developed, information contents and services provided through them have also become available in a broad variety. The mobile phone systems capable of accessing the Internet have become very popular in Japan in the past…

  14. A Novel 2-D OFDM-DS-CDMA Receiver with Frequency-Time Spreading

    NASA Astrophysics Data System (ADS)

    Chen, Joy Iong-Zong

    This paper presents a novel 2-D (2-dimension) receiver that adopts the reception scheme to promote OFDM-DS-CDMA (orthogonal frequency division multiplexing multi-carrier coded-division multiple-access) system performance. The system model includes spread coding and a system block diagram of the 2-D receiver shown graphically with 3-D (three dimensions) plots. The analytical calculation of system performance for an OFDM-DS-CDMA system combined with the proposed receiver equipment is investigated. To evaluate the results from the channel fading effect is considered over the correlated fading environments. The correlated-Nakagami-m statistical distribution is taken into account in the evaluation. The results show that the number of users, the number of subcarriers and the fading channel correlation generally affect OFDM-DS-CDMA systems. The system is also influenced by the Doppler shift and the signal propagation environment (fading parameter).

  15. Authomatization of Digital Collection Access Using Mobile and Wireless Data Terminals

    NASA Astrophysics Data System (ADS)

    Leontiev, I. V.

    Information technologies become vital due to information processing needs, database access, data analysis and decision support. Currently, a lot of scientific projects are oriented on database integration of heterogeneous systems. The problem of on-line and rapid access to large integrated systems of digital collections is also very important. Usually users move between different locations, either at work or at home. In most cases users need an efficient and remote access to information, stored in integrated data collections. Desktop computers are unable to fulfill the needs, so mobile and wireless devices become helpful. Handhelds and data terminals are nessessary in medical assistance (they store detailed information about each patient, and helpful for nurses), immediate access to data collections is used in a Highway patrol services (databanks of cars, owners, driver licences). Using mobile access, warehouse operations can be validated. Library and museum items cyclecounting will speed up using online barcode-scanning and central database access. That's why mobile devices - cell phones, PDA, handheld computers with wireless access, WindowsCE and PalmOS terminals become popular. Generally, mobile devices have a relatively slow processor, and limited display capabilities, but they are effective for storing and displaying textual data, recognize user hand-writing with stylus, support GUI. Users can perform operations on handheld terminal, and exchange data with the main system (using immediate radio access, or offline access during syncronization process) for update. In our report, we give an approach for mobile access to data collections, which raises an efficiency of data processing in a book library, helps to control available books, books in stock, validate service charges, eliminate staff mistakes, generate requests for book delivery. Our system uses mobile devices Symbol RF (with radio-channel access), and data terminals Symbol Palm Terminal for batch

  16. 36 CFR 1192.23 - Mobility aid accessibility.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... deployed unless the interlocks or systems are engaged. The lift shall deploy to all levels (i.e., ground... lift shall incorporate an emergency method of deploying, lowering to ground level with a lift occupant... of the wheels of a wheelchair or mobility aid from rolling off the platform during its operation....

  17. 49 CFR 38.125 - Mobility aid accessibility.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... mobility aid maneuverability when entering or leaving the car. (c) Car ramp or bridge plate—(1) Design load. Ramps or bridge plates 30 inches or longer shall support a load of 600 pounds, placed at the centroid of... inches shall support a load of 300 pounds. (2) Ramp surface. The ramp or bridge plate surface shall...

  18. 49 CFR 38.159 - Mobility aid accessibility.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    .... (7) Seat belt and shoulder harness. For each wheelchair or mobility aid securement device provided, a passenger seat belt and shoulder harness, complying with all applicable provisions of the Federal Motor... users. Such seat belts and shoulder harnesses shall not be used in lieu of a device which secures...

  19. Effects of mobility and location on food access.

    PubMed

    Coveney, John; O'Dwyer, Lisel A

    2009-03-01

    Access to healthy food has become an important area of investigation for researchers interested in health disparities and inequalities. The debate about the existence and characteristics of 'food deserts' has increased the interest in food availability and equity in health research. This debate is crucial to an understanding of the factors leading to food security. Research reported here used in-depth interviews with respondents without private transport living within and outside food deserts in Adelaide, South Australia. The respondents came from a variety of households, including single and double parent families, and people living alone. The research found that living in a food desert did not, by itself, impose food access difficulties. Far more important was the access to independent transport to shops. A number of features were identified in this research including reliance on supermarkets, difficulties with public transport, and the provision of government schemes and systems that for some made food shopping much easier. The research suggests that food access problems in Adelaide are not so much the product of geographic distance between home and shop, as the social or welfare networks that allow people to access private transport.

  20. An efficient CDMA decoder for correlated information sources

    NASA Astrophysics Data System (ADS)

    Efraim, Hadar; Yacov, Nadav; Shental, Ori; Kanter, Ido

    2009-07-01

    We consider the detection of correlated information sources in the ubiquitous code-division multiple-access (CDMA) scheme. We propose a message-passing based scheme for detecting correlated sources directly, with no need for source coding. The detection is done simultaneously over a block of transmitted binary symbols (word). Simulation results are provided, demonstrating a substantial improvement in bit error rate in comparison with the unmodified detector and the alternative of source compression. The robustness of the error-performance improvement is shown under practical model settings, including wrong estimation of the generating Markov transition matrix and finite-length spreading codes.

  1. Propagation of 2.5 Gb/s Asynchronous, Concurrent, Optical CDMA Signals Through a 214 Kilometer Fiber Optic Link

    SciTech Connect

    Mendez, A.J.; Feng, H.X.C.; Heritage, J.P.; Morookian, J.; Gagliardi, R.M.

    2000-03-16

    The propagation of optical Code Division Multiple Access (CDMA) signals was studied by computer simulation. Group velocity dispersion produces the worst impairment. With dispersion management, the decoder successfully recovers the signals, even in the presence of severe multi-access interference.

  2. Creating a mobile subject guide to improve access to point-of-care resources for medical students: a case study

    PubMed Central

    Boruff, Jill T; Bilodeau, Edward

    2012-01-01

    Question: Can a mobile optimized subject guide facilitate medical student access to mobile point-of-care tools? Setting: The guide was created at a library at a research-intensive university with six teaching hospital sites. Objectives: The team created a guide facilitating medical student access to point-of-care tools directly on mobile devices to provide information allowing them to access and set up resources with little assistance. Methods: Two librarians designed a mobile optimized subject guide for medicine and conducted a survey to test its usefulness. Results: Web analytics and survey results demonstrate that the guide is used and the students are satisfied. Conclusion: The library will continue to use the subject guide as its primary means of supporting mobile devices. It remains to be seen if the mobile guide facilitates access for those who do not need assistance and want direct access to the resources. Internet access in the hospitals remains an issue. PMID:22272160

  3. Mobile Access to Clinical Information at the Point of Care

    PubMed Central

    Mncube-Barnes, Fatima M.; Lee, Ben; Esuruoso, Olumuyiwa; Gona, Phil N.; Daphnis, Stephane

    2016-01-01

    Objectives Using library subscriptions and accessible on handheld devices, this study sought to promote authoritative health information apps, and evidence-based point-of-care resources. Methods Three cohorts of internal medicine residents were issued iPads at the beginning of their second year, and were trained to skillfully access resources from the digital library. Pre- and post-intervention surveys were respectively administered at the beginning of the second year and end of the third year of training. The residents' computer experience and computer knowledge was assessed. Additionally, before and after formal introduction to iPads, perceptions on the use of computers to access clinical information were assessed. Survey responses were compared using two sample methods and summarized through descriptive statistics. Results Sixty-eight residents completed the pre-survey questionnaires and 45 completed the post-surveys. There were significant improvements in the residents' level of computer experience, and familiarity with medical apps. Furthermore, there was increased knowledge obtained in accessing clinical information through electronic medical records. Residents positively perceived the potential effects of computers and electronic medical records in medicine. Conclusion Study findings suggested that health science libraries can be instrumental in providing search skills to health professionals, especially residents in training. Participants showed appreciation of iPads and library support that facilitated successful completion of their related tasks. Replicating this study with a larger sample derived from multiple sites is recommended for future studies. Participation of mid-level healthcare professionals, such as Physician Assistants and Nurse Practitioners is suggested. PMID:28210418

  4. Application of Fiber-Optical Techniques in the Access Transmission and Backbone Transport of Mobile Networks

    NASA Astrophysics Data System (ADS)

    Hilt, Attila; Pozsonyi, László

    2012-09-01

    Fixed access networks widely employ fiber-optical techniques due to the extremely wide bandwidth offered to subscribers. In the last decade, there has also been an enormous increase of user data visible in mobile systems. The importance of fiber-optical techniques within the fixed transmission/transport networks of mobile systems is therefore inevitably increasing. This article summarizes a few reasons and gives examples why and how fiber-optic techniques are employed efficiently in second-generation networks.

  5. Equalization With Oversampling in Multiuser CDMA Systems

    DTIC Science & Technology

    2007-11-02

    A Mutually-Orthogonal Usercode-Receiver ( AMOUR ) for asynchronous or quasi-synchronous CDMA systems. AMOUR converts a multiuser CDMA system into...of improving the performance of AMOUR systems. They design Fractionally-Spaced AMOUR (FSAMOUR) receivers with integral and rational amounts of...practically guaranteed. They exploit this flexibility in the design of AMOUR and FSAMOUR receivers and achieve noticeable improvements in performance. (11 figures, 23 refs.)

  6. Access Scheme for Controlling Mobile Agents and its Application to Share Medical Information.

    PubMed

    Liao, Yu-Ting; Chen, Tzer-Shyong; Chen, Tzer-Long; Chung, Yu-Fang; Chen, Yu- Xin; Hwang, Jen-Hung; Wang, Huihui; Wei, Wei

    2016-05-01

    This study is showing the advantage of mobile agents to conquer heterogeneous system environments and contribute to a virtual integrated sharing system. Mobile agents will collect medical information from each medical institution as a method to achieve the medical purpose of data sharing. Besides, this research also provides an access control and key management mechanism by adopting Public key cryptography and Lagrange interpolation. The safety analysis of the system is based on a network attacker's perspective. The achievement of this study tries to improve the medical quality, prevent wasting medical resources and make medical resources access to appropriate configuration.

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

    NASA Astrophysics Data System (ADS)

    Kollár, Martin

    2012-05-01

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

  8. Modelling of Medium Access Control (MAC) Protocols for Mobile Ad-Hoc Networks

    DTIC Science & Technology

    2005-06-01

    Slot IP Internet Protocol LAN Local Area Network MAC Medium Access Control MACAW Medium Access Protocol for Wireless LANs MANET Mobile Ad-hoc...Unforced state – It waits after entering the state until it is invoked by another process or an interrupt. It is in dark grey on this report, and red ... green in OPNET. A MAC process model is built for general initialisations of the MAC module, and to invoke the selected MAC protocol process model

  9. Random access to mobile networks with advanced error correction

    NASA Technical Reports Server (NTRS)

    Dippold, Michael

    1990-01-01

    A random access scheme for unreliable data channels is investigated in conjunction with an adaptive Hybrid-II Automatic Repeat Request (ARQ) scheme using Rate Compatible Punctured Codes (RCPC) Forward Error Correction (FEC). A simple scheme with fixed frame length and equal slot sizes is chosen and reservation is implicit by the first packet transmitted randomly in a free slot, similar to Reservation Aloha. This allows the further transmission of redundancy if the last decoding attempt failed. Results show that a high channel utilization and superior throughput can be achieved with this scheme that shows a quite low implementation complexity. For the example of an interleaved Rayleigh channel and soft decision utilization and mean delay are calculated. A utilization of 40 percent may be achieved for a frame with the number of slots being equal to half the station number under high traffic load. The effects of feedback channel errors and some countermeasures are discussed.

  10. Random access to mobile networks with advanced error correction

    NASA Astrophysics Data System (ADS)

    Dippold, Michael

    A random access scheme for unreliable data channels is investigated in conjunction with an adaptive Hybrid-II Automatic Repeat Request (ARQ) scheme using Rate Compatible Punctured Codes (RCPC) Forward Error Correction (FEC). A simple scheme with fixed frame length and equal slot sizes is chosen and reservation is implicit by the first packet transmitted randomly in a free slot, similar to Reservation Aloha. This allows the further transmission of redundancy if the last decoding attempt failed. Results show that a high channel utilization and superior throughput can be achieved with this scheme that shows a quite low implementation complexity. For the example of an interleaved Rayleigh channel and soft decision utilization and mean delay are calculated. A utilization of 40 percent may be achieved for a frame with the number of slots being equal to half the station number under high traffic load. The effects of feedback channel errors and some countermeasures are discussed.

  11. Female mobility and postmarital kin access in a patrilocal society.

    PubMed

    Scelza, Brooke A

    2011-12-01

    Across a wide variety of cultural settings, kin have been shown to play an important role in promoting women's reproductive success. Patrilocal postmarital residence is a potential hindrance to maintaining these support networks, raising the question: how do women preserve and foster relationships with their natal kin when propinquity is disrupted? Using census and interview data from the Himba, a group of semi-nomadic African pastoralists, I first show that although women have reduced kin propinquity after marriage, more than half of married women are visiting with their kin at a given time. Mobility recall data further show that married women travel more than unmarried women, and that women consistently return to stay with kin around the time of giving birth. Divorce and death of a spouse also trigger a return to living with kin, leading to a cumulative pattern of kin coresidence across the lifespan. These data suggest that patrilocality may be less of a constraint on female kin support than has been previously assumed.

  12. A Model for Trust-based Access Control and Delegation in Mobile Clouds (Post Print)

    DTIC Science & Technology

    2013-10-01

    Qing-Guo, Z., Rong, L.: An Access Control Model for Ubiquitous Computing Application. In: Proceedings of the 2nd International Conference on Mobile ... Technology , Applications and Systems, Guangzhou, China (November 2005) 22. Baracaldo, N., Joshi, J.B.D.: A Trust-and-Risk Aware RBAC Framework: Tackling

  13. Overlapping Chat's Accessibility Requirements between Students with and without Disabilities Due to the Mobile Limitations

    ERIC Educational Resources Information Center

    Calvo, Rocío; Iglesias, Ana; Moreno, Lourdes

    2014-01-01

    The use of Chats has been extended to mobile-learning (m-learning) environments in the last decade. Students and teachers can communicate in real time and they do not need waiting till their next tutoring date to solve their problems and doubts. However, Chats have many accessibility barriers and many students cannot use this collaborative tool.…

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

    NASA Technical Reports Server (NTRS)

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

    1988-01-01

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

  15. Mobility and Hierarchy in the Age of Near-Universal Access

    ERIC Educational Resources Information Center

    Parry, Gareth

    2011-01-01

    With the shift toward near-universal access, the movement of students within and between systems of higher education has assumed a new importance, especially for policies aimed at widening participation and social equity. Globalization has given rise to increasing levels of student mobility across national boundaries, with participation in…

  16. Progress on Broadband Access to the Internet and Use of Mobile Devices in the United States.

    PubMed

    Serrano, Katrina J; Thai, Chan L; Greenberg, Alexandra J; Blake, Kelly D; Moser, Richard P; Hesse, Bradford W

    Healthy People 2020 (HP2020) aims to improve population health outcomes through several objectives, including health communication and health information technology. We used 7 administrations of the Health Information National Trends Survey to examine HP2020 goals toward access to the Internet through broadband and mobile devices (N = 34 080). We conducted descriptive analyses and obtained predicted marginals, also known as model-adjusted risks, to estimate the association between demographic characteristics and use of mobile devices. The HP2020 target (7.7% of the US population) for accessing the Internet through a cellular network was surpassed in 2014 (59.7%), but the HP2020 target (83.2%) for broadband access fell short (63.8%). Sex and age were associated with accessing the Internet through a cellular network throughout the years (Wald F test, P <.05). The increase in the percentage of people accessing the Internet through mobile devices presents an opportunity for technology-based health interventions that should be explored.

  17. 75 FR 47304 - Accessible Mobile Phone Options for People Who Are Blind, Deaf-Blind, or Have Low Vision

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-08-05

    ... COMMISSION Accessible Mobile Phone Options for People Who Are Blind, Deaf- Blind, or Have Low Vision AGENCY...-145, which shall be captioned ``Accessible Mobile Phone Options for People who are Blind, Deaf-blind... following issues: The wireless phone features and functions in the current marketplace that are...

  18. A mobile agent approach to access and represent remote spatial information in LBS

    NASA Astrophysics Data System (ADS)

    Fang, Zhixiang; Li, Qingquan; Luo, Zhi; Geng, Xuexian

    2005-10-01

    The mobile computing based Location based Service (LBS) technology has been increasingly grown in the past decade; however there still exist some important constraints that complicate work with a mobile spatial information system. The limited resources in the mobile computing terminals would restrict some features that are available on the traditional computing technology. This paper will explores the use of a cooperative, distributed multi-agent systems (Java Agent Development Framework, JADE) to improve the efficiency of accessing and represent remote spatial information in mobile terminals and fixed terminal which support Java runtime environment (JRE), because that JADE system has following features: distributed agent platform, graphical user interface to manage several agents and agent containers form remote host, supporting to execution of multiple, parallel and concurrent agent activities via behavior model, FIPA-compliant platform including AMS (Agent Management System), DF (Directory Facilitator) and ACC (Agent Communication Channel), Efficient transport of ACL messages inside same agent system, library of FIPA interaction protocols ready to be used, FIPA-compliant naming service and supporting for application-defined content languages and ontology. An agile and flexible agent based approach for accessing and representing remote spatial information is proposed in this paper, mobile agent system architecture in LBS is presented, and a prototype system is given to shown that JADE makes this approach feasible and effective.

  19. An Optimal Mobile Service for Telecare Data Synchronization using a Role-based Access Control Model and Mobile Peer-to-Peer Technology.

    PubMed

    Ke, Chih-Kun; Lin, Zheng-Hua

    2015-09-01

    The progress of information and communication technologies (ICT) has promoted the development of healthcare which has enabled the exchange of resources and services between organizations. Organizations want to integrate mobile devices into their hospital information systems (HIS) due to the convenience to employees who are then able to perform specific healthcare processes from any location. The collection and merage of healthcare data from discrete mobile devices are worth exploring possible ways for further use, especially in remote districts without public data network (PDN) to connect the HIS. In this study, we propose an optimal mobile service which automatically synchronizes the telecare file resources among discrete mobile devices. The proposed service enforces some technical methods. The role-based access control model defines the telecare file resources accessing mechanism; the symmetric data encryption method protects telecare file resources transmitted over a mobile peer-to-peer network. The multi-criteria decision analysis method, ELECTRE (Elimination Et Choice Translating Reality), evaluates multiple criteria of the candidates' mobile devices to determine a ranking order. This optimizes the synchronization of telecare file resources among discrete mobile devices. A prototype system is implemented to examine the proposed mobile service. The results of the experiment show that the proposed mobile service can automatically and effectively synchronize telecare file resources among discrete mobile devices. The contribution of this experiment is to provide an optimal mobile service that enhances the security of telecare file resource synchronization and strengthens an organization's mobility.

  20. Development of Pulse Position Modulation/Optical CDMA (PPM/O-CDMA) for Gb/s Fiber Optic Networking

    SciTech Connect

    Mendez, A J; Hernandez, V J; Gagliardi, R M; Bennett, C V; Lennon, W J

    2006-05-25

    Pulse position modulation (PPM) in lasercom systems is known to provide potential advantages over other modulation schemes. [1]. In PPM, a periodic time frame is established and data is transmitted by placing a pulse in any one of several subintervals (or ''slots'') within each frame. In PPM/O-CDMA all users use the same frame structure and each transmits its unique address code in place of the PPM pulse. The advantage of PPM as a pulsed signal format is that (1) a single pulse can transmit multiple bits during each frame; (2) decoding (determining which subinterval contains the pulse) is by comparison rather than threshold tests (as in on-off-keying); (3) each user transmits in only a small fraction of the frame, hence the multi-access interference (MAI) of any user statistically spreads over the entire frame time, reducing the chance of overlap with any other user; and (4) under an average power constraint, increasing frame time increases the peak pulse power (i.e., PPM trades average power for peak power). The most straightforward approach to implementing PPM/O-CDMA data modulator inserts the PPM pulse modulation first, then imposes the O-CDMA coding. A pulsed PPM modulator converts bits (words) into pulse positions. In the case of wavelength/time (W/T) matrix codes, multi-wavelength pulses are generated at the beginning of each frame, at the frame rate. For M-ary PPM, a block of k bits represents M = 2{sup k} unique interval positions in the frame corresponding to M-l specific time delays (the zero delay is also a position). PPM modulation is achieved by shifting the initial pulse into an interval position with delay D(i) (i=0,1,2,..,M-1). The location of a pulse position (selection of a delay) therefore identifies a unique k-bit word in the frame. At the receiver, determining which delay occurs relative to the frame start time decodes the data word. The probability of pulse overlap between two users decreases with M, which therefore decreases the probability

  1. Using Mobile Fruit Vendors to Increase Access to Fresh Fruit and Vegetables for Schoolchildren

    PubMed Central

    Yen, Irene H.; Laraia, Barbara

    2012-01-01

    This study explored the extent to which schoolchildren purchased precut and bagged fruits and vegetables from a mobile fruit vendor (frutero). During 14 days in fall 2008, a frutero sold fruits and vegetables at the entrance of an elementary school; 59% of the frutero’s 233 consumers of 248 items were elementary-school students. With each successive day, an average of 1 additional bag of fruits and vegetables was sold by the frutero and 1.5 fewer nonnutritious foods by a competing vendor. Policies encouraging the sale of nutritious foods from mobile food vendors may increase access for schoolchildren. PMID:22632739

  2. Conducting a fully mobile and randomised clinical trial for depression: access, engagement and expense

    PubMed Central

    Jordan, Joshua T; Castaneda, Diego; Gazzaley, Adam; Areán, Patricia A

    2016-01-01

    Importance Advances in mobile technology have resulted in federal and industry-level initiatives to facilitate large-scale clinical research using smart devices. Although the benefits of technology to expand data collection are obvious, assumptions about the reach of mobile research methods (access), participant willingness to engage in mobile research protocols (engagement), and the cost of this research (cost) remain untested. Objective To assess the feasibility of a fully mobile randomised controlled trial using assessments and treatments delivered entirely through mobile devices to depressed individuals. Design Using a web-based research portal, adult participants with depression who also owned a smart device were screened, consented and randomised to 1 of 3 mental health apps for treatment. Assessments of self-reported mood and cognitive function were conducted at baseline, 4, 8 and 12 weeks. Physical and social activity was monitored daily using passively collected phone use data. All treatment and assessment tools were housed on each participant's smart phone or tablet. Interventions A cognitive training application, an application based on problem-solving therapy, and a mobile-sensing application promoting daily activities. Results Access: We screened 2923 people and enrolled 1098 participants in 5 months. The sample characteristics were comparable to the 2013 US census data. Recruitment via Craigslist.org yielded the largest sample. Engagement: Study engagement was high during the first 2 weeks of treatment, falling to 44% adherence by the 4th week. Cost: The total amount spent on for this project, including staff costs and β testing, was $314 264 over 2 years. Conclusions and relevance These findings suggest that mobile randomised control trials can recruit large numbers of participants in a short period of time and with minimal cost, but study engagement remains challenging. Trial registration number NCT00540865. PMID:27019745

  3. Pilot-Assisted Channel Estimation for Orthogonal Multi-Carrier DS-CDMA with Frequency-Domain Equalization

    NASA Astrophysics Data System (ADS)

    Shima, Tomoyuki; Tomeba, Hiromichi; Adachi, Fumiyuki

    Orthogonal multi-carrier direct sequence code division multiple access (orthogonal MC DS-CDMA) is a combination of time-domain spreading and orthogonal frequency division multiplexing (OFDM). In orthogonal MC DS-CDMA, the frequency diversity gain can be obtained by applying frequency-domain equalization (FDE) based on minimum mean square error (MMSE) criterion to a block of OFDM symbols and can improve the bit error rate (BER) performance in a severe frequency-selective fading channel. FDE requires an accurate estimate of the channel gain. The channel gain can be estimated by removing the pilot modulation in the frequency domain. In this paper, we propose a pilot-assisted channel estimation suitable for orthogonal MC DS-CDMA with FDE and evaluate, by computer simulation, the BER performance in a frequency-selective Rayleigh fading channel.

  4. Literacy Disparities in Patient Access and Health-Related Use of Internet and Mobile Technologies

    PubMed Central

    Bailey, Stacy Cooper; O’Conor, Rachel; Bojarski, Elizabeth A.; Mullen, Rebecca; Patzer, Rachel E.; Vicencio, Daniel; Jacobson, Kara L.; Parker, Ruth M.; Wolf, Michael S.

    2014-01-01

    Background Age and race-related disparities in technology use have been well documented, but less is known about how health literacy influences technology access and use. Objective To assess the association between patients’ literacy skills and mobile phone ownership, use of text messaging, internet access, and use of the internet for health-related purposes. Methods A secondary analysis utilizing data from 1,077 primary care patients enrolled in two, multi-site studies from 2011–2013. Patients were administered an in-person, structured interview. Results Patients with adequate health literacy were more likely to own a mobile phone or smartphone in comparison to patients with low or marginal literacy (mobile phone ownership: 96.8% vs. 95.2% vs. 90.1%, respectively, p<.001; smartphone ownership: 70.6% vs. 62.5% vs. 40.1%, p<.001) and to report text messaging (78.6% vs. 75.2% vs. 53.1%, p<.001). They were also more likely to have access to the internet from their home (92.1% vs. 74.7% vs. 44.9%, p<.001) and to report using the internet for email (93.0% vs. 75.7% vs. 38.5%, p<.001), browsing the web (93.9% vs. 80.2% vs. 44.5%, p<.001), accessing health information (86.3% vs. 75.5% vs. 40.8%, p<.001), and communicating with providers (54.2% vs. 29.8% vs. 13.0%, p<.001). Relationships remained significant in multivariable analyses controlling for relevant covariates. Conclusions Results reveal that literacy-related disparities in technology access and use are widespread, with lower literate patients being less likely to own smartphones or to access and use the internet, particularly for health reasons. Future interventions should consider these disparities and ensure that health promotion activities do not further exacerbate disparities. PMID:25363660

  5. Optical CDMA system using 2-D run-length limited code

    NASA Astrophysics Data System (ADS)

    Liu, Maw-Yang; Jiang, Joe-Air

    2010-10-01

    In this paper, time-spreading wavelength-hopping optical CDMA system using 2-D run-length limited code is investigated. The run-length limited code we use here is predicated upon spatial coding scheme, which can improve system performance significantly. In our proposed system, we employ carrier-hopping prime code and its shifted version as signature sequences. Based on the zero auto-correlation sidelobes property of signature sequence, we propose a two-state trellis coding architecture, which utilizes 2-D parallel detection scheme. The proposed scheme is compact and simple that can be applied to more complicated trellis to further enhance system performance. Multiple access interference is the main deterioration factor in optical CDMA system that affects system performance adversely. Aside from the multiple access interference, some of the adverse impacts of system performance are also taken into consideration, which include thermal noise, shot noise, relative intensity noise, and beat noise.

  6. Computer and cell phone access for individuals with mobility impairments: an overview and case studies.

    PubMed

    Burgstahler, Sheryl; Comden, Dan; Lee, Sang-Mook; Arnold, Anthony; Brown, Kayla

    2011-01-01

    Computers, telephones, and assistive technology hold promise for increasing the independence, productivity, and participation of individuals with disabilities in academic, employment, recreation, and other activities. However, to reach this goal, technology must be accessible to, available to, and usable by everyone. The authors of this article share computer and telephone access challenges faced by individuals with neurological and other impairments, assistive technology solutions, issues that impact product adoption and use, needs for new technologies, and recommendations for practitioners and researchers. They highlight the stories of three individuals with neurological/mobility impairments, the technology they have found useful to them, and their recommendations for future product development.

  7. In-field Access to Geoscientific Metadata through GPS-enabled Mobile Phones

    NASA Astrophysics Data System (ADS)

    Hobona, Gobe; Jackson, Mike; Jordan, Colm; Butchart, Ben

    2010-05-01

    Fieldwork is an integral part of much geosciences research. But whilst geoscientists have physical or online access to data collections whilst in the laboratory or at base stations, equivalent in-field access is not standard or straightforward. The increasing availability of mobile internet and GPS-supported mobile phones, however, now provides the basis for addressing this issue. The SPACER project was commissioned by the Rapid Innovation initiative of the UK Joint Information Systems Committee (JISC) to explore the potential for GPS-enabled mobile phones to access geoscientific metadata collections. Metadata collections within the geosciences and the wider geospatial domain can be disseminated through web services based on the Catalogue Service for Web(CSW) standard of the Open Geospatial Consortium (OGC) - a global grouping of over 380 private, public and academic organisations aiming to improve interoperability between geospatial technologies. CSW offers an XML-over-HTTP interface for querying and retrieval of geospatial metadata. By default, the metadata returned by CSW is based on the ISO19115 standard and encoded in XML conformant to ISO19139. The SPACER project has created a prototype application that enables mobile phones to send queries to CSW containing user-defined keywords and coordinates acquired from GPS devices built-into the phones. The prototype has been developed using the free and open source Google Android platform. The mobile application offers views for listing titles, presenting multiple metadata elements and a Google Map with an overlay of bounding coordinates of datasets. The presentation will describe the architecture and approach applied in the development of the prototype.

  8. A High Speed Mobile Courier Data Access System That Processes Database Queries in Real-Time

    NASA Astrophysics Data System (ADS)

    Gatsheni, Barnabas Ndlovu; Mabizela, Zwelakhe

    A secure high-speed query processing mobile courier data access (MCDA) system for a Courier Company has been developed. This system uses the wireless networks in combination with wired networks for updating a live database at the courier centre in real-time by an offsite worker (the Courier). The system is protected by VPN based on IPsec. There is no system that we know of to date that performs the task for the courier as proposed in this paper.

  9. The digital divide: Trends in global mobile and broadband Internet access from 2000-2010.

    PubMed

    Ronquillo, Charlene; Currie, Leanne

    2012-01-01

    The digital divide is described as the gap between those who do and do not have access to digital information and communications technologies (ICT). ICTs are viewed as an indicator of infrastructure and potential for development, and are a growing platform for health information and services delivery. This study compares the penetration of mobile and broadband Internet technologies by global region from 2000 to 2010. Results illustrate the rapid growth of mobile cellular telephone subscriptions in all global regions with trends suggesting a continued increase. Little to modest gains were made in fixed broadband Internet subscriptions globally. There is a growing popularity of mobile subscriptions with use of data communications, exceeding the numbers of fixed Internet subscriptions. This comparison reveals current strengths that can be built on and highlights the importance of awareness of global trends and using such knowledge to inform design and delivery of ICT-based health services.

  10. Direct sequence CDMA power control, interleaving, and coding

    NASA Astrophysics Data System (ADS)

    Simpson, Floyd; Holtzman, Jack M.

    1993-09-01

    We develop and analyze models of power control working with other aspects of CDMA systems, such as interleaving and coding on the land/ mobile radio channel. Our orientation is that a power control scheme is keeping the received powers at the base station 'almost equal', and we will be quantifying the performance degradation incurred if the powers are not exactly equal. In doing so, we consider the performance implications of control latency and a maximum speech delay constraint. It turns out that because of positive correlations between the fading channel amplitudes, the effectiveness of the combination of interleaving and coding in combating the effects of power variations due to slow Rayleigh fading is reduced. It is shown however, that power control and interleaving/coding are most effective in complementary parameter regions, thus providing a degree of robustness for both fast and slow Rayleigh fading.

  11. The Potential of Using a Mobile Phone to Access the Internet for Learning EFL Listening Skills within a Korean Context

    ERIC Educational Resources Information Center

    Nah, Ki Chune; White, Peter; Sussex, Roland

    2008-01-01

    Interest in the use of a mobile phone to access the Internet for learning English in general, and listening skills in particular, has been increasing in Korea over the last few years. However, there has been only a small number of studies on this topic in Korea. The present paper investigates the potential of using a mobile phone to browse…

  12. 2-Step Maximum Likelihood Channel Estimation for Multicode DS-CDMA with Frequency-Domain Equalization

    NASA Astrophysics Data System (ADS)

    Kojima, Yohei; Takeda, Kazuaki; Adachi, Fumiyuki

    Frequency-domain equalization (FDE) based on the minimum mean square error (MMSE) criterion can provide better downlink bit error rate (BER) performance of direct sequence code division multiple access (DS-CDMA) than the conventional rake combining in a frequency-selective fading channel. FDE requires accurate channel estimation. In this paper, we propose a new 2-step maximum likelihood channel estimation (MLCE) for DS-CDMA with FDE in a very slow frequency-selective fading environment. The 1st step uses the conventional pilot-assisted MMSE-CE and the 2nd step carries out the MLCE using decision feedback from the 1st step. The BER performance improvement achieved by 2-step MLCE over pilot assisted MMSE-CE is confirmed by computer simulation.

  13. PAPR reduction in SFBC MIMO MC-CDMA systems via user reservation

    NASA Astrophysics Data System (ADS)

    García-Otero, Mariano; Paredes-Hernández, Luis Alberto

    2011-12-01

    The combination of multicarrier code-division multiple access (MC-CDMA) with multiple-input multiple-output technology is attractive for broadband wireless communications. However, the large values of the peak-to-average power ratio (PAPR) of the signals transmitted on different antennas can lead to nonlinear distortion and a subsequent degradation of the system performance. In this article, we propose a PAPR reduction scheme for space-frequency block coding MC-CDMA downlink transmissions that does not require any processing at the receiver side because it is based on the addition of signals employing the spreading codes of inactive users. As the minimization of the PAPR leads to a second-order cone programming problem that can be too cumbersome for a practical implementation, some strategies to mitigate the complexity of the proposed method are also explored.

  14. Fast-responder: Rapid mobile-phone access to recent remote sensing imagery for first responders

    NASA Astrophysics Data System (ADS)

    Talbot, L. M.; Talbot, B. G.

    We introduce Fast-Responder, a novel prototype data-dissemination application and architecture concept to rapidly deliver remote sensing imagery to smartphones to enable situational awareness. The architecture implements a Fast-Earth image caching system on the phone and interacts with a Fast-Earth server. Prototype evaluation successfully demonstrated that National Guard users could select a location, download multiple remote sensing images, and flicker between images, all in less than a minute on a 3G mobile commercial link. The Fast-Responder architecture is a significant advance that is designed to meet the needs of mobile users, such as National Guard response units, to rapidly access information during a crisis, such as a natural or man-made disaster. This paper focuses on the architecture design and advanced user interface concepts for small-screens for highly active mobile users. Novel Fast-Responder concepts can also enable rapid dissemination and evaluation of imagery on the desktop, opening new technology horizons for both desktop and mobile users.

  15. Improving Inpatient Surveys: Web-Based Computer Adaptive Testing Accessed via Mobile Phone QR Codes

    PubMed Central

    2016-01-01

    Background The National Health Service (NHS) 70-item inpatient questionnaire surveys inpatients on their perceptions of their hospitalization experience. However, it imposes more burden on the patient than other similar surveys. The literature shows that computerized adaptive testing (CAT) based on item response theory can help shorten the item length of a questionnaire without compromising its precision. Objective Our aim was to investigate whether CAT can be (1) efficient with item reduction and (2) used with quick response (QR) codes scanned by mobile phones. Methods After downloading the 2008 inpatient survey data from the Picker Institute Europe website and analyzing the difficulties of this 70-item questionnaire, we used an author-made Excel program using the Rasch partial credit model to simulate 1000 patients’ true scores followed by a standard normal distribution. The CAT was compared to two other scenarios of answering all items (AAI) and the randomized selection method (RSM), as we investigated item length (efficiency) and measurement accuracy. The author-made Web-based CAT program for gathering patient feedback was effectively accessed from mobile phones by scanning the QR code. Results We found that the CAT can be more efficient for patients answering questions (ie, fewer items to respond to) than either AAI or RSM without compromising its measurement accuracy. A Web-based CAT inpatient survey accessed by scanning a QR code on a mobile phone was viable for gathering inpatient satisfaction responses. Conclusions With advances in technology, patients can now be offered alternatives for providing feedback about hospitalization satisfaction. This Web-based CAT is a possible option in health care settings for reducing the number of survey items, as well as offering an innovative QR code access. PMID:26935793

  16. Breaking and Fixing Origin-Based Access Control in Hybrid Web/Mobile Application Frameworks

    PubMed Central

    Georgiev, Martin; Jana, Suman; Shmatikov, Vitaly

    2014-01-01

    Hybrid mobile applications (apps) combine the features of Web applications and “native” mobile apps. Like Web applications, they are implemented in portable, platform-independent languages such as HTML and JavaScript. Like native apps, they have direct access to local device resources—file system, location, camera, contacts, etc. Hybrid apps are typically developed using hybrid application frameworks such as PhoneGap. The purpose of the framework is twofold. First, it provides an embedded Web browser (for example, WebView on Android) that executes the app's Web code. Second, it supplies “bridges” that allow Web code to escape the browser and access local resources on the device. We analyze the software stack created by hybrid frameworks and demonstrate that it does not properly compose the access-control policies governing Web code and local code, respectively. Web code is governed by the same origin policy, whereas local code is governed by the access-control policy of the operating system (for example, user-granted permissions in Android). The bridges added by the framework to the browser have the same local access rights as the entire application, but are not correctly protected by the same origin policy. This opens the door to fracking attacks, which allow foreign-origin Web content included into a hybrid app (e.g., ads confined in iframes) to drill through the layers and directly access device resources. Fracking vulnerabilities are generic: they affect all hybrid frameworks, all embedded Web browsers, all bridge mechanisms, and all platforms on which these frameworks are deployed. We study the prevalence of fracking vulnerabilities in free Android apps based on the PhoneGap framework. Each vulnerability exposes sensitive local resources—the ability to read and write contacts list, local files, etc.—to dozens of potentially malicious Web domains. We also analyze the defenses deployed by hybrid frameworks to prevent resource access by foreign

  17. Breaking and Fixing Origin-Based Access Control in Hybrid Web/Mobile Application Frameworks.

    PubMed

    Georgiev, Martin; Jana, Suman; Shmatikov, Vitaly

    2014-02-01

    Hybrid mobile applications (apps) combine the features of Web applications and "native" mobile apps. Like Web applications, they are implemented in portable, platform-independent languages such as HTML and JavaScript. Like native apps, they have direct access to local device resources-file system, location, camera, contacts, etc. Hybrid apps are typically developed using hybrid application frameworks such as PhoneGap. The purpose of the framework is twofold. First, it provides an embedded Web browser (for example, WebView on Android) that executes the app's Web code. Second, it supplies "bridges" that allow Web code to escape the browser and access local resources on the device. We analyze the software stack created by hybrid frameworks and demonstrate that it does not properly compose the access-control policies governing Web code and local code, respectively. Web code is governed by the same origin policy, whereas local code is governed by the access-control policy of the operating system (for example, user-granted permissions in Android). The bridges added by the framework to the browser have the same local access rights as the entire application, but are not correctly protected by the same origin policy. This opens the door to fracking attacks, which allow foreign-origin Web content included into a hybrid app (e.g., ads confined in iframes) to drill through the layers and directly access device resources. Fracking vulnerabilities are generic: they affect all hybrid frameworks, all embedded Web browsers, all bridge mechanisms, and all platforms on which these frameworks are deployed. We study the prevalence of fracking vulnerabilities in free Android apps based on the PhoneGap framework. Each vulnerability exposes sensitive local resources-the ability to read and write contacts list, local files, etc.-to dozens of potentially malicious Web domains. We also analyze the defenses deployed by hybrid frameworks to prevent resource access by foreign-origin Web content

  18. An integrated voice and data multiple-access scheme for a land-mobile satellite system

    NASA Technical Reports Server (NTRS)

    Li, V. O. K.; Yan, T.-Y.

    1984-01-01

    An analytical study is performed of the satellite requirements for a land mobile satellite system (LMSS). The spacecraft (MSAT-X) would be in GEO and would be compatible with multiple access by mobile radios and antennas and fixed stations. The FCC has received a petition from NASA to reserve the 821-825 and 866-870 MHz frequencies for the LMSS, while communications with fixed earth stations would be in the Ku band. MSAT-X transponders would alter the frequencies of signal and do no processing in the original configuration considered. Channel use would be governed by an integrated demand-assigned, multiple access protocol, which would divide channels into reservation and information channels, governed by a network management center. Further analyses will cover tradeoffs between data and voice users, probability of blocking, and the performance impacts of on-board switching and variable bandwidth assignment. Initial calculations indicate that a large traffic volume can be handled with acceptable delays and voice blocking probabilities.

  19. RCSB PDB Mobile: iOS and Android mobile apps to provide data access and visualization to the RCSB Protein Data Bank

    PubMed Central

    Quinn, Gregory B.; Bi, Chunxiao; Christie, Cole H.; Pang, Kyle; Prlić, Andreas; Nakane, Takanori; Zardecki, Christine; Voigt, Maria; Berman, Helen M.; Rose, Peter W.

    2015-01-01

    Summary: The Research Collaboratory for Structural Bioinformatics Protein Data Bank (RCSB PDB) resource provides tools for query, analysis and visualization of the 3D structures in the PDB archive. As the mobile Web is starting to surpass desktop and laptop usage, scientists and educators are beginning to integrate mobile devices into their research and teaching. In response, we have developed the RCSB PDB Mobile app for the iOS and Android mobile platforms to enable fast and convenient access to RCSB PDB data and services. Using the app, users from the general public to expert researchers can quickly search and visualize biomolecules, and add personal annotations via the RCSB PDB’s integrated MyPDB service. Availability and implementation: RCSB PDB Mobile is freely available from the Apple App Store and Google Play (http://www.rcsb.org). Contact: pwrose@ucsd.edu PMID:25183487

  20. PKI-based secure mobile access to electronic health services and data.

    PubMed

    Kambourakis, G; Maglogiannis, I; Rouskas, A

    2005-01-01

    Recent research works examine the potential employment of public-key cryptography schemes in e-health environments. In such systems, where a Public Key Infrastructure (PKI) is established beforehand, Attribute Certificates (ACs) and public key enabled protocols like TLS, can provide the appropriate mechanisms to effectively support authentication, authorization and confidentiality services. In other words, mutual trust and secure communications between all the stakeholders, namely physicians, patients and e-health service providers, can be successfully established and maintained. Furthermore, as the recently introduced mobile devices with access to computer-based patient record systems are expanding, the need of physicians and nurses to interact increasingly with such systems arises. Considering public key infrastructure requirements for mobile online health networks, this paper discusses the potential use of Attribute Certificates (ACs) in an anticipated trust model. Typical trust interactions among doctors, patients and e-health providers are presented, indicating that resourceful security mechanisms and trust control can be obtained and implemented. The application of attribute certificates to support medical mobile service provision along with the utilization of the de-facto TLS protocol to offer competent confidentiality and authorization services is also presented and evaluated through experimentation, using both the 802.11 WLAN and General Packet Radio Service (GPRS) networks.

  1. Physical Accessibility of Routine Prenatal Care for Women with Mobility Disability

    PubMed Central

    Wint, Amy J.; Smeltzer, Suzanne C.; Ecker, Jeffrey L.

    2015-01-01

    Abstract Background: Routine prenatal care includes physical examinations and weight measurement. Little is known about whether access barriers to medical diagnostic equipment, such as examination tables and weight scales, affect prenatal care among pregnant women with physical disabilities. Methods: We conducted 2-hour, in-depth telephone interviews with 22 women using a semistructured, open-ended interview protocol. All women had significant mobility difficulties before pregnancy and had delivered babies within the prior 10 years. We recruited most participants through social networks. We sorted interview transcript texts using used NVivo software and conducted conventional content analyses to identify major themes. Results: Interviewee's mean (standard deviation) age was 34.8 (5.3) years. Most were white, well-educated, and higher income; 8 women had spinal cord injuries, 4 cerebral palsy, and 10 had other conditions; 18 used wheeled mobility aids. Some women's obstetricians had height adjustable examination tables, which facilitated transfers for physical examinations. Other women had difficulty transferring onto fixed height examination tables and were examined while sitting in their wheelchairs. Family members and/or clinical staff sometimes assisted with transfers; some women reported concerns about transfer safety. No women reported being routinely weighed on an accessible weight scale by their prenatal care clinicians. A few were never weighed during their pregnancies. Conclusions: Inaccessible examination tables and weight scales impede some pregnant women with physical disabilities from getting routine prenatal physical examinations and weight measurement. This represents substandard care. Adjustable height examination tables and wheelchair accessible weight scales could significantly improve care and comfort for pregnant women with physical disabilities. PMID:26484689

  2. A pilot study on mobile phones as a means to access maternal health education in eastern rural Uganda.

    PubMed

    Roberts, Sanford; Birgisson, Natalia; Julia Chang, Diana; Koopman, Cheryl

    2015-01-01

    Maternal mortality in Uganda has remained relatively high since 2006. We studied access to mobile phones and people's interest in receiving audio-based maternal health lessons delivered via a toll-free telephone line. Interviews were conducted, using a male and a female translator, with 42 men and 41 women in four villages located in eastern rural Uganda. Most of the participants were recruited through systematic sampling, but some were recruited through community organizations and antenatal clinics. Ownership of a mobile phone was reported by 79% of men and by 42% of women. Among those who did not own a mobile phone, 67% of men and 88% of women reported regularly borrowing a mobile phone. Among women, 98% reported interest in receiving maternal mobile health lessons, and 100% of men. Providing local communities with mobile maternal health education offers a new potential method of reducing maternal mortality.

  3. Blind ICA detection based on second-order cone programming for MC-CDMA systems

    NASA Astrophysics Data System (ADS)

    Jen, Chih-Wei; Jou, Shyh-Jye

    2014-12-01

    The multicarrier code division multiple access (MC-CDMA) technique has received considerable interest for its potential application to future wireless communication systems due to its high data rate. A common problem regarding the blind multiuser detectors used in MC-CDMA systems is that they are extremely sensitive to the complex channel environment. Besides, the perturbation of colored noise may negatively affect the performance of the system. In this paper, a new coherent detection method will be proposed, which utilizes the modified fast independent component analysis (FastICA) algorithm, based on approximate negentropy maximization that is subject to the second-order cone programming (SOCP) constraint. The aim of the proposed coherent detection is to provide robustness against small-to-medium channel estimation mismatch (CEM) that may arise from channel frequency response estimation error in the MC-CDMA system, which is modulated by downlink binary phase-shift keying (BPSK) under colored noise. Noncoherent demodulation schemes are preferable to coherent demodulation schemes, as the latter are difficult to implement over time-varying fading channels. Differential phase-shift keying (DPSK) is therefore the natural choice for an alternative modulation scheme. Furthermore, the new blind differential SOCP-based ICA (SOCP-ICA) detection without channel estimation and compensation will be proposed to combat Doppler spread caused by time-varying fading channels in the DPSK-modulated MC-CDMA system under colored noise. In this paper, numerical simulations are used to illustrate the robustness of the proposed blind coherent SOCP-ICA detector against small-to-medium CEM and to emphasize the advantage of the blind differential SOCP-ICA detector in overcoming Doppler spread.

  4. The Effects of Spatial Diversity and Imperfect Channel Estimation on Wideband MC-DS-CDMA and MC-CDMA

    DTIC Science & Technology

    2009-10-01

    input multiple-output (MIMO) system which employs Alamouti spacetime block coding at each sub-carrier frequency to achieve spatial diversity. We...number of pilot symbols per channel estimate. 13 N/A MC-DS-CDMA, MC-CDMA, Alamouti spacetime block coding, frequency-selective Rayleigh fading

  5. Frequency-Domain Equalization for Broadband Single-Carrier Multiple Access

    NASA Astrophysics Data System (ADS)

    Adachi, Fumiyuki; Tomeba, Hiromichi; Takeda, Kazuki

    Single-carrier (SC) multiple access is a promising uplink multiple access technique because of its low peak-to-average power ratio (PAPR) property and high frequency diversity gain that is achievable through simple one-tap frequency-domain equalization (FDE) in a strong frequency-selective channel. The multiple access capability can be obtained by combining either frequency division multiple access (FDMA) or code division multiple access (CDMA) with SC transmission. In this article, we review the recent research on the SC multiple access techniques with one-tap FDE. After introducing the principle of joint FDE/antenna diversity combining, we review various SC multiple access techniques with one-tap FDE, i.e., SC-FDMA, SC-CDMA, block spread CDMA, and delay-time/CDMA.

  6. Orthogonal Pilot Channel Using Combination of FDMA and CDMA in Single-Carrier FDMA-Based Evolved UTRA Uplink

    NASA Astrophysics Data System (ADS)

    Kawamura, Teruo; Kishiyama, Yoshihisa; Higuchi, Kenichi; Sawahashi, Mamoru

    In the Evolved UTRA (UMTS Terrestrial Radio Access) uplink, single-carrier frequency division multiple access (SC-FDMA) radio access was adopted owing to its advantageous low peak-to-average power ratio (PAPR) feature, which leads to wide coverage area provisioning with limited peak transmission power of user equipments. This paper proposes orthogonal pilot channel generation using the combination of FDMA and CDMA in the SC-FDMA-based Evolved UTRA uplink. In the proposed method, we employ distributed FDMA transmission for simultaneous accessing users with different transmission bandwidths, and employ CDMA transmission for simultaneous accessing users with identical transmission bandwidth. Moreover, we apply a code sequence with a good auto-correlation property such as a Constant Amplitude Zero Auto-Correlation (CAZAC) sequence employing a cyclic shift to increase the number of sequences. Simulation results show that the average packet error rate performance using an orthogonal pilot channel with the combination of FDMA and CDMA in a six-user environment, i. e., four users each with a 1.25-MHz transmission bandwidth and two users each with a 5-MHz transmission bandwidth, employing turbo coding with the coding r of R=1/2 and QPSK and 16QAM data modulation coincides well with that in a single-user environment with the same transmission bandwidth. We show that the proposed orthogonal pilot channel structure using the combination of distributed FDMA and CDMA transmissions and the application of the CAZAC sequence is effective in the SC-FDMA-based Evolved UTRA uplink.

  7. Nurses’ Use of Mobile Devices to Access Information in Health Care Environments in Australia: A Survey of Undergraduate Students

    PubMed Central

    2014-01-01

    Background The growth of digital technology has created challenges for safe and appropriate use of mobile or portable devices during work-integrated learning (WIL) in health care environments. Personal and professional use of technology has outpaced the development of policy or codes of practice for guiding its use at the workplace. There is a perceived risk that portable devices may distract from provision of patient or client care if used by health professionals or students during employment or WIL. Objective This study aimed to identify differences in behavior of undergraduate nurses in accessing information, using a portable or mobile device, when undertaking WIL compared to other non-work situations. Methods A validated online survey was administered to students while on placement in a range of health care settings in two Australian states. Results There were 84 respondents, with 56% (n=47) reporting access to a mobile or portable device. Differences in use of a mobile device away from, compared with during WIL, were observed for non-work related activities such as messaging (P<.001), social networking (P<.001), shopping on the Internet (P=.01), conducting personal business online (P=.01), and checking or sending non-work related texts or emails to co-workers (P=.04). Study-related activities were conducted more regularly away from the workplace and included accessing University sites for information (P=.03) and checking or sending study-related text messages or emails to friends or co-workers (P=.01). Students continued to access nursing, medical, professional development, and study-related information away from the workplace. Conclusions Undergraduate nurses limit their access to non-work or non-patient centered information while undertaking WIL. Work-related mobile learning is being undertaken, in situ, by the next generation of nurses who expect easy access to mobile or portable devices at the workplace, to ensure safe and competent care is delivered to

  8. RCSB PDB Mobile: iOS and Android mobile apps to provide data access and visualization to the RCSB Protein Data Bank

    SciTech Connect

    Quinn, Gregory B.; Bi, Chunxiao; Christie, Cole H.; Pang, Kyle; Prlic, Andreas; Nakane, Takanori; Zardecki, Christine; Voigt, Maria; Berman, Helen M.; Bourne, Philip E.; Rose, Peter W.

    2014-09-02

    The Research Collaboratory for Structural Bioinformatics Protein Data Bank (RCSB PDB) resource provides tools for query, analysis and visualization of the 3D structures in the PDB archive. As the mobile Web is starting to surpass desktop and laptop usage, scientists and educators are beginning to integrate mobile devices into their research and teaching. In response, we have developed the RCSB PDB Mobile app for the iOS and Android mobile platforms to enable fast and convenient access to RCSB PDB data and services. Lastly, using the app, users from the general public to expert researchers can quickly search and visualize biomolecules, and add personal annotations via the RCSB PDB's integrated MyPDB service.

  9. RCSB PDB Mobile: iOS and Android mobile apps to provide data access and visualization to the RCSB Protein Data Bank

    DOE PAGES

    Quinn, Gregory B.; Bi, Chunxiao; Christie, Cole H.; ...

    2014-09-02

    The Research Collaboratory for Structural Bioinformatics Protein Data Bank (RCSB PDB) resource provides tools for query, analysis and visualization of the 3D structures in the PDB archive. As the mobile Web is starting to surpass desktop and laptop usage, scientists and educators are beginning to integrate mobile devices into their research and teaching. In response, we have developed the RCSB PDB Mobile app for the iOS and Android mobile platforms to enable fast and convenient access to RCSB PDB data and services. Lastly, using the app, users from the general public to expert researchers can quickly search and visualize biomolecules,more » and add personal annotations via the RCSB PDB's integrated MyPDB service.« less

  10. Ultrasonic array for obstacle detection based on CDMA with Kasami codes.

    PubMed

    Diego, Cristina; Hernández, Alvaro; Jiménez, Ana; Alvarez, Fernando J; Sanz, Rebeca; Aparicio, Joaquín

    2011-01-01

    This paper raises the design of an ultrasonic array for obstacle detection based on Phased Array (PA) techniques, which steers the acoustic beam through the environment by electronics rather than mechanical means. The transmission of every element in the array has been encoded, according to Code Division for Multiple Access (CDMA), which allows multiple beams to be transmitted simultaneously. All these features together enable a parallel scanning system which does not only improve the image rate but also achieves longer inspection distances in comparison with conventional PA techniques.

  11. Linear CDMA Detection Algorithm Based on Statistical Neurodynamics and Belief Propagation and the Stability Conditions

    NASA Astrophysics Data System (ADS)

    Shojiguchi, A.; Tanaka, T.; Okada, M.

    Recently a modified algorithm of code-division multiple-access (CDMA) parallel interference canceler (PIC) has been proposed by Tanaka based on statistical neurodynamics. In this paper we apply the modified algorithm to the linear PIC (LPIC) and investigate its stability. We show that the stable (unstable) fixed points of the modified algorithm correspond to the stable (unstable) replica symmetry solutions with the Gaussian prior. We also show the modified algorithm is a special case of Kabashima's belief-propagation algorithm with Gaussian prior.

  12. Minimum Kullback-Leibler-Based Turbo Multiuser Detector over Decomposition CDMA Signal

    NASA Astrophysics Data System (ADS)

    Ploysuwan, Tuchsanai; Tantiphanwadi, Sawat; Teekaput, Prasit

    In this paper, we develop a new iterative turbo multiuser detector for direct sequence code-division multiple access (DS-CDMA) systems over unknown frequency-selective channels by decomposing the observation signal into a number of signal components. Virtual trellis model representing the ISI channel for each separating signal user is designed to generate extrinsic probability in term of BCJR algorithm for exchange with a single channel decoder as priori information. Minimum kullback-leibler (MKL) framework is derived to calculate numerical channel estimation and extrinsic probability. In comparison with other similar receiver, simulation results demonstrate that the proposed solution achieves the desirable performance.

  13. Access, Use and Perceptions of Teachers and Students towards Mobile Phones as a Tool for Teaching and Learning in Tanzania

    ERIC Educational Resources Information Center

    Kafyulilo, Ayoub

    2014-01-01

    This study explored the access, use and perceptions of teachers and students towards mobile phones as a tool for facilitating teaching and learning beyond the classroom walls. A total of 29 pre-service teachers and four college instructors from Dar es salaam University College of Education (DUCE) as well as 12 in-service teachers and 40 students…

  14. Interaction Problems Accessing E-Learning Environments in Multi-Touch Mobile Devices: A Case Study in TelEduc

    ERIC Educational Resources Information Center

    da Silva, André Constantino; Freire, Fernanda Maria Pereira; de Arruda, Alan Victor Pereira; da Rocha, Heloísa Vieira

    2013-01-01

    e-Learning environments offer content, such text, audio, video, animations, using the Web infrastructure and they are designed to users interacting with keyboard, mouse and a medium-sized screen. Mobile devices, such as smartphones and tablets, have enough computation power to render Web pages, allowing browsing the Internet and access e-Learning…

  15. Effects on rat testis of 1.95-GHz W-CDMA for IMT-2000 cellular phones.

    PubMed

    Imai, Norio; Kawabe, Mayumi; Hikage, Takashi; Nojima, Toshio; Takahashi, Satoru; Shirai, Tomoyuki

    2011-08-01

    In recent years concern has arisen whether carrying a cellular phone near the reproductive organs such as the testes may cause dysfunction and particularly decrease in sperm development and production, and thus fertility in men. The present study was performed to investigate the effects of a 1.95 GHz electromagnetic field on testicular function in male Sprague-Dawley rats. Five week old animals were divided into 3 groups of 24 each and a 1.95-GHz wide-band code division multiple access (W-CDMA) signal, which is used for the freedom of mobile multimedia access (FOMA), was employed for whole body exposure for 5 hours per day, 7 days a week for 5 weeks (the period from the age of 5 to 10 weeks, corresponding to reproductive maturation in the rat). Whole-body average specific absorption rates (SAR) for individuals were designed to be 0.4 and 0.08 W/kg respectively. The control group received sham exposure. There were no differences in body weight gain or weights of the testis, epididymis, seminal vesicles, and prostate among the groups. The number of sperm in the testis and epididymis were not decreased in the electromagnetic field (EMF) exposed groups, and, in fact, the testicular sperm count was significantly increased with the 0.4 SAR. Abnormalities of sperm motility or morphology and the histological appearance of seminiferous tubules, including the stage of the spermatogenic cycle, were not observed. Thus, under the present exposure conditions, no testicular toxicity was evident.

  16. Performance analysis of an adaptive multiple access scheme for the message service of a land mobile satellite experiment (MSAT-X)

    NASA Technical Reports Server (NTRS)

    Yan, T.-Y.; Li, V. O. K.

    1984-01-01

    This paper describes an Adaptive Mobile Access Protocol (AMAP) for the message service of MSAT-X., a proposed experimental mobile satellite communication network. Message lengths generated by the mobiles are assumed to be uniformly distributed. The mobiles are dispersed over a wide geographical area and the channel data rate is limited. AMAP is a reservation based multiple access scheme. The available bandwidth is divided into subchannels, which are divided into reservation and message channels. The ALOHA multiple access scheme is employed in the reservation channels, while the message channels are demand assigned. AMAP adaptively reallocates the reservation and message channels to optimize the total average message delay.

  17. Access to Mobile Communication Technology and Willingness to Participate in Automated Telemedicine Calls Among Chronically Ill Patients in Honduras

    PubMed Central

    Mendoza-Avelares, Milton O.; Milton, Evan C.; Lange, Ilta; Fajardo, Roosevelt

    2010-01-01

    Abstract Objectives: Patients in underdeveloped countries may be left behind by advances in telehealthcare. We surveyed chronically ill patients with low incomes in Honduras to measure their use of mobile technologies and willingness to participate in mobile disease management support. Materials and Methods: 624 chronically ill primary care patients in Honduras were surveyed. We examined variation in telephone access across groups defined by patients' sociodemographic characteristics, diagnoses, and access to care. Logistic regression was used to identify independent correlates of patients' interest in automated telephonic support for disease management. Results: Participants had limited education (mean 4.8 years), and 65% were unemployed. Eighty-four percent had telephone access, and 78% had cell phones. Most respondents had voicemail (61%) and text messaging (58%). Mobile technologies were particularly common among patients who had to forego clinic visits and medications due to cost concerns (each p < 0.05). Most patients (>80%) reported that they would be willing to receive automated calls focused on appointment reminders, medication adherence, health status monitoring, and self-care education. Patients were more likely to be willing to participate in automated telemedicine services if they had to cancel a clinic appointment due to transportation problems or forego medication due to cost pressures. Conclusions: Even in this poor region of Honduras, most chronically ill patients have access to mobile technology, and most are willing to participate in automated telephone disease management support. Given barriers to in-person care, new models of mobile healthcare should be developed for chronically ill patients in developing countries. PMID:21062234

  18. U.S. Minority Homeless Youth's Access to and Use of Mobile Phones: Implications for mHealth Intervention Design.

    PubMed

    Jennings, Larissa; Lee, Nicole; Shore, Deborah; Strohminger, Nancy; Allison, Burgundi; Conserve, Donaldson F; Cheskin, Lawrence J

    2016-07-01

    Few interventions for homeless youth have leveraged the potential of mHealth technologies, in part because of the limited data on phone behaviors, perceptions, and intervention preferences among youth experiencing homelessness. We conducted 9 focus groups (n = 52 homeless youth) and 41 individual structured interviews also with homeless youth in underserved communities in Baltimore and Washington, DC, to ascertain how youth perceived their mobile phone, acquired and maintained mobile services over time, and thought mHealth programs for this population should be designed. We also measured phone use, functionality, source, duration of ownership, and reasons for changing phones or numbers. Results showed that mobile coverage was high, as most youth self-purchased phones or received gift payments from others. Maintaining mobile connectivity was often challenging because of financial constraints and interpersonal conflict. Youth valued phones to access social support but used several tactics to avoid perceived negative consequences of phone ownership, such as harassment, theft, or relational disputes. Youth most preferred mHealth content relating to sexual, reproductive, and mental health provided that mobile communication was confidential, empowering, and integrated with other digital media. Integrating hidden phones, financial support, and safety management may improve homeless youth's access to and engagement with mHealth strategies over time.

  19. Pervasive access to images and data--the use of computing grids and mobile/wireless devices across healthcare enterprises.

    PubMed

    Pohjonen, Hanna; Ross, Peeter; Blickman, Johan G; Kamman, Richard

    2007-01-01

    Emerging technologies are transforming the workflows in healthcare enterprises. Computing grids and handheld mobile/wireless devices are providing clinicians with enterprise-wide access to all patient data and analysis tools on a pervasive basis. In this paper, emerging technologies are presented that provide computing grids and streaming-based access to image and data management functions, and system architectures that enable pervasive computing on a cost-effective basis. Finally, the implications of such technologies are investigated regarding the positive impacts on clinical workflows.

  20. Quantum internet using code division multiple access.

    PubMed

    Zhang, Jing; Liu, Yu-xi; Ozdemir, Sahin Kaya; Wu, Re-Bing; Gao, Feifei; Wang, Xiang-Bin; Yang, Lan; Nori, Franco

    2013-01-01

    A crucial open problem inS large-scale quantum networks is how to efficiently transmit quantum data among many pairs of users via a common data-transmission medium. We propose a solution by developing a quantum code division multiple access (q-CDMA) approach in which quantum information is chaotically encoded to spread its spectral content, and then decoded via chaos synchronization to separate different sender-receiver pairs. In comparison to other existing approaches, such as frequency division multiple access (FDMA), the proposed q-CDMA can greatly increase the information rates per channel used, especially for very noisy quantum channels.

  1. Quantum internet using code division multiple access

    NASA Astrophysics Data System (ADS)

    Zhang, Jing; Liu, Yu-Xi; Özdemir, Şahin Kaya; Wu, Re-Bing; Gao, Feifei; Wang, Xiang-Bin; Yang, Lan; Nori, Franco

    2013-07-01

    A crucial open problem inS large-scale quantum networks is how to efficiently transmit quantum data among many pairs of users via a common data-transmission medium. We propose a solution by developing a quantum code division multiple access (q-CDMA) approach in which quantum information is chaotically encoded to spread its spectral content, and then decoded via chaos synchronization to separate different sender-receiver pairs. In comparison to other existing approaches, such as frequency division multiple access (FDMA), the proposed q-CDMA can greatly increase the information rates per channel used, especially for very noisy quantum channels.

  2. Quantum internet using code division multiple access

    PubMed Central

    Zhang, Jing; Liu, Yu-xi; Özdemir, Şahin Kaya; Wu, Re-Bing; Gao, Feifei; Wang, Xiang-Bin; Yang, Lan; Nori, Franco

    2013-01-01

    A crucial open problem inS large-scale quantum networks is how to efficiently transmit quantum data among many pairs of users via a common data-transmission medium. We propose a solution by developing a quantum code division multiple access (q-CDMA) approach in which quantum information is chaotically encoded to spread its spectral content, and then decoded via chaos synchronization to separate different sender-receiver pairs. In comparison to other existing approaches, such as frequency division multiple access (FDMA), the proposed q-CDMA can greatly increase the information rates per channel used, especially for very noisy quantum channels. PMID:23860488

  3. Enabling Access to Medical and Health Education in Rwanda Using Mobile Technology: Needs Assessment for the Development of Mobile Medical Educator Apps

    PubMed Central

    Tomaszewski, Brian; Dusabejambo, Vincent; Ndayiragije, Vincent; Gonsalves, Snedden; Sawant, Aishwarya; Mumararungu, Angeline; Gasana, George; Amendezo, Etienne; Haake, Anne; Mutesa, Leon

    2016-01-01

    Background Lack of access to health and medical education resources for doctors in the developing world is a serious global health problem. In Rwanda, with a population of 11 million, there is only one medical school, hence a shortage in well-trained medical staff. The growth of interactive health technologies has played a role in the improvement of health care in developed countries and has offered alternative ways to offer continuous medical education while improving patient's care. However, low and middle-income countries (LMIC) like Rwanda have struggled to implement medical education technologies adapted to local settings in medical practice and continuing education. Developing a user-centered mobile computing approach for medical and health education programs has potential to bring continuous medical education to doctors in rural and urban areas of Rwanda and influence patient care outcomes. Objective The aim of this study is to determine user requirements, currently available resources, and perspectives for potential medical education technologies in Rwanda. Methods Information baseline and needs assessments data collection were conducted in all 44 district hospitals (DHs) throughout Rwanda. The research team collected qualitative data through interviews with 16 general practitioners working across Rwanda and 97 self-administered online questionnaires for rural areas. Data were collected and analyzed to address two key questions: (1) what are the currently available tools for the use of mobile-based technology for medical education in Rwanda, and (2) what are user's requirements for the creation of a mobile medical education technology in Rwanda? Results General practitioners from different hospitals highlighted that none of the available technologies avail local resources such as the Ministry of Health (MOH) clinical treatment guidelines. Considering the number of patients that doctors see in Rwanda, an average of 32 patients per day, there is need for a

  4. Dynamic Key Management Schemes for Secure Group Access Control Using Hierarchical Clustering in Mobile Ad Hoc Networks

    NASA Astrophysics Data System (ADS)

    Tsaur, Woei-Jiunn; Pai, Haw-Tyng

    2008-11-01

    The applications of group computing and communication motivate the requirement to provide group access control in mobile ad hoc networks (MANETs). The operation in MANETs' groups performs a decentralized manner and accommodated membership dynamically. Moreover, due to lack of centralized control, MANETs' groups are inherently insecure and vulnerable to attacks from both within and outside the groups. Such features make access control more challenging in MANETs. Recently, several researchers have proposed group access control mechanisms in MANETs based on a variety of threshold signatures. However, these mechanisms cannot actually satisfy MANETs' dynamic environments. This is because the threshold-based mechanisms cannot be achieved when the number of members is not up to the threshold value. Hence, by combining the efficient elliptic curve cryptosystem, self-certified public key cryptosystem and secure filter technique, we construct dynamic key management schemes based on hierarchical clustering for securing group access control in MANETs. Specifically, the proposed schemes can constantly accomplish secure group access control only by renewing the secure filters of few cluster heads, when a cluster head joins or leaves a cross-cluster. In such a new way, we can find that the proposed group access control scheme can be very effective for securing practical applications in MANETs.

  5. Preparing Teachers for a Mobile World, to Improve Access to Education

    ERIC Educational Resources Information Center

    Ally, Mohamed; Grimus, Margarete; Ebner, Martin

    2014-01-01

    Recent statistics on the use of mobile technology proclaim that the world is becoming mobile. People use their phones to socialize, to conduct business, to search for information, and more. For the first time in history, people around the world have the potential to learn from any location at their own convenience. But first, education systems…

  6. Average Likelihood Methods for Code Division Multiple Access (CDMA)

    DTIC Science & Technology

    2014-05-01

    AFOSR). Some of the work accomplished was possible by using the AFRL High Performance Computing servers ( Condor HPC). Approved for Public Release...A Matlab implementation of the parameters is shown below. The code was executed using AFRL Condor HPC cluster for calculating the values of

  7. Mobile Health Access for Diabetics in Rural Areas of Turkey - Results of a Survey

    NASA Astrophysics Data System (ADS)

    Seker, Emine; Savini, Marco

    Extending the reach of medical professionals in rural areas is one of the goals using mobile health technologies. This paper illustrates the results of a survey conducted in 2008 in Turkey asking medical professionals about their current ICT usage and opinions about using mobile technologies in order to help patients with diabetes. The goal is to reduce the information gap between patients and medical professionals by allowing sending the information electronically using mobile technologies. This will improve both the interaction between various actors and also improve the treatment, as important trends of this chronic disease can be discovered on time.

  8. A CDMA Spotbeam Architecture for the Next Generation Satellite System (NGSS) for the Aeronautical Telecommunications Network (ATN)

    NASA Technical Reports Server (NTRS)

    Raghavan, Rajesh S.; Shamma, Mohammed A.

    2003-01-01

    This paper will present work being done to model and simulate a CDMA based Mobile Satellite System architecture for providing all or part of the future Air Traffic Management (ATM) services. Such a system, will help in relieving the dependence on ground based networks, if not eliminate it. Additionally such an architecture can be used in parallel or as a supplementary service along with ground based links to help alleviate any capacity bottlenecks, or in areas where such services are difficult to make available such as in oceanic, remote areas outside the jet highways, or in developing countries where ground services are less available.

  9. Accessibility

    EPA Pesticide Factsheets

    Federal laws, including Section 508 of the Rehabilitation Act, mandate that people with disabilities have access to the same information that someone without a disability would have. 508 standards cover electronic and information technology (EIT) products.

  10. Wavelet-based compression with ROI coding support for mobile access to DICOM images over heterogeneous radio networks.

    PubMed

    Maglogiannis, Ilias; Doukas, Charalampos; Kormentzas, George; Pliakas, Thomas

    2009-07-01

    Most of the commercial medical image viewers do not provide scalability in image compression and/or region of interest (ROI) encoding/decoding. Furthermore, these viewers do not take into consideration the special requirements and needs of a heterogeneous radio setting that is constituted by different access technologies [e.g., general packet radio services (GPRS)/ universal mobile telecommunications system (UMTS), wireless local area network (WLAN), and digital video broadcasting (DVB-H)]. This paper discusses a medical application that contains a viewer for digital imaging and communications in medicine (DICOM) images as a core module. The proposed application enables scalable wavelet-based compression, retrieval, and decompression of DICOM medical images and also supports ROI coding/decoding. Furthermore, the presented application is appropriate for use by mobile devices activating in heterogeneous radio settings. In this context, performance issues regarding the usage of the proposed application in the case of a prototype heterogeneous system setup are also discussed.

  11. Accessing best practice resources using mobile technology in an undergraduate nursing program: a feasibility study.

    PubMed

    Mann, Elizabeth G; Medves, Jennifer; Vandenkerkhof, Elizabeth G

    2015-03-01

    Mobile technology presents new opportunities for nursing education and ultimately the provision of nursing care. The aim of this study was to explore the utility of mobile technology in undergraduate nursing education. In this evaluation study, undergraduate nursing students were provided with iPod Touch devices containing best practice guidelines. Computer self-efficacy was assessed, and the Theory of Planned Behavior was used to identify potential predictors of the use of mobile technology. Questionnaires were completed at baseline (n = 33) and postimplementation (n = 23). Feedback on feasibility issues was recorded throughout the study period. Students generally found the devices useful, and few technical problems were identified; however, lack of skill in using the devices and lack of support from staff in the clinical setting were commonly identified issues. Self-efficacy scores were high throughout the study. Attitudes, perceptions of the desirability of use, perceived personal control over use, and intentions of using the device were lower postimplementation than at baseline. Attitude toward the technology predicted intention to use the device after graduation. Mobile technology may promote evidence-informed practice; however, supporting students' acquisition of related skills may optimize use. Successful integration of mobile technology into practice requires attention to factors that affect student attitudes.

  12. Mobilizing positive reinforcement in communities to reduce youth access to tobacco.

    PubMed

    Biglan, A; Ary, D; Koehn, V; Levings, D; Smith, S; Wright, Z; James, L; Henderson, J

    1996-10-01

    A community intervention to mobilize positive reinforcement for not selling tobacco to young people was evaluated. The intervention had five components: (a) mobilization of community support, (b) merchant education, (c) changing consequences to clerks for selling or not selling to those under 18, (d) publicity about clerks' refusals to sell, and (e) feedback to store owners or managers about the extent of their sales to adolescents. A multiple baseline design experiment was conducted, in which two small Oregon communities received the intervention, while two other continued in baseline. Outlets' willingness to sell was assessed repeatedly by teenage volunteers. The intervention significantly reduced the proportion of stores willing to sell. Mobilizing social and material reinforcement for stores not selling tobacco to young people is a viable means of reducing such sales. It may be especially valuable in communities where laws against sales to minors go unenforced.

  13. J2ME implementation of system for storing and accessing of sensitive data on patient's mobile device

    NASA Astrophysics Data System (ADS)

    Zabołotny, Wojciech M.; Wielgórski, Radosław; Nowik, Marcin

    2011-10-01

    This paper presents a system allowing to use a patient's mobile phone or PDA for storing of biomedical data, which then, during medical consultation or intervention may be used by the medical staff. The presented solution is aimed on providing both: reliable protection to sensitive patient's data, and easy access to information for authorized medical staff. In the presented system, data are stored in an encrypted form, and the encryption key is available only for authorized persons. The central authentication server verifies the current access rights of the person trying to obtain the information, before providing him or her with the key needed to access the patient's data. The key provided by the server is valid only for the particular device, which minimizes the risk of its misuse. For rare situations when no connection to the authentication server is available (e.g. intervention in the mountains or rural area), system assures an additional "emergency" method to access the encryption key in controlled, registered way. The system has been implemented in Java language and tested in the simulated environment provided by Sun Java Wireless Toolkit for CLDC.

  14. Ka-band geostationary satellite spacing requirements and access schemes

    NASA Technical Reports Server (NTRS)

    Caron, Mario; Hindson, Daniel J.

    1995-01-01

    Geostationary satellite systems for wideband personal communications applications have been proposed. This paper looks at the geostationary satellite spacing requirement to meet the ITU-R sharing criterion for FDMA and CDMA access schemes. CDMA capacity equation is first developed. Then the basis for the interference analysis between two systems with an overlapping coverage area is developed for the cases of identical and different access schemes and for bandwidth and power limited systems. An example of an interference analysis between two systems is fully carried out. The paper also points out the inherent problems when comparing systems with different access schemes. It is found that under certain scenarios, CDMA can allow a closer spacing between satellites.

  15. Schooling for Social Mobility: High School Reform for College Access and Success

    ERIC Educational Resources Information Center

    Hammack, Floyd M.

    2016-01-01

    This article addresses what schools that seek to promote social mobility as opposed to status maintenance among their students really ask of them. Focusing on several prominent charter school organizations, the article details the social and behavioral expectations of the schools and understands them through an application of Goffman's work on…

  16. Chaotic CDMA watermarking algorithm for digital image in FRFT domain

    NASA Astrophysics Data System (ADS)

    Liu, Weizhong; Yang, Wentao; Feng, Zhuoming; Zou, Xuecheng

    2007-11-01

    A digital image-watermarking algorithm based on fractional Fourier transform (FRFT) domain is presented by utilizing chaotic CDMA technique in this paper. As a popular and typical transmission technique, CDMA has many advantages such as privacy, anti-jamming and low power spectral density, which can provide robustness against image distortions and malicious attempts to remove or tamper with the watermark. A super-hybrid chaotic map, with good auto-correlation and cross-correlation characteristics, is adopted to produce many quasi-orthogonal codes (QOC) that can replace the periodic PN-code used in traditional CDAM system. The watermarking data is divided into a lot of segments that correspond to different chaotic QOC respectively and are modulated into the CDMA watermarking data embedded into low-frequency amplitude coefficients of FRFT domain of the cover image. During watermark detection, each chaotic QOC extracts its corresponding watermarking segment by calculating correlation coefficients between chaotic QOC and watermarked data of the detected image. The CDMA technique not only can enhance the robustness of watermark but also can compress the data of the modulated watermark. Experimental results show that the watermarking algorithm has good performances in three aspects: better imperceptibility, anti-attack robustness and security.

  17. Efficiency droop effects of GaN-based light-emitting diodes on the performance of code division multiple access visible-light communication system

    NASA Astrophysics Data System (ADS)

    Lu, Huimin; Yan, Chaowen; Gao, Wei; Yu, Tongjun; Wang, Jianping

    2016-02-01

    The physical mechanism in efficiency droop of GaN-based light-emitting diodes (LEDs) was investigated using a modified rate equation model considering inhomogeneous carrier distribution and was compared with the measured result. On this basis, the efficiency droop effect on the performance of a code division multiple access (CDMA) visible-light communication (VLC) system using GaN-based LEDs was also analyzed. The results reveal that the obvious transmitted signal error under the effect of LED efficiency droop leads to performance deterioration of multiuser CDMA VLC systems. Also, the performance of CDMA VLC systems is reduced with the user number increase due to LED efficiency droop. The bit error rate of a CDMA VLC system was further calculated for different branch signal levels and bias currents. It is demonstrated that the efficiency droop effect on the performance of CDMA VLC systems can be alleviated by adjusting the branch signal level and the bias current.

  18. Time-spreading wavelength-hopping optical CDMA system using EWO and TCM

    NASA Astrophysics Data System (ADS)

    Liu, Maw-Yang; Wang, Zhi-Wei

    2011-12-01

    In this paper, time-spreading wavelength-hopping optical CDMA system using trellis coded modulation scheme is investigated. The carrier hopping prime code and its shifted version are employed as signature sequences. Since the carrier hopping prime code is a symmetric code, the out of phase autocorrelation is zero. Applying the orthogonality of the signature sequences, the ternary transmission mechanism can be achieved. The proposed coding scheme is simple in both transmitter and receiver. As the multiple access interference and beat noise are the major deterioration of system performance, using coding scheme is an effective way to reduce the error floor. The numerical results reveal that the proposed coding scheme can significantly improve the system performance.

  19. A Randomized Controlled Trial of a Mobile Clinical Decision Aid to Improve Access to Kidney Transplantation: iChoose Kidney

    PubMed Central

    Patzer, Rachel E.; Basu, Mohua; Mohan, Sumit; Smith, Kayla D.; Wolf, Michael; Ladner, Daniela; Friedewald, John J.; Chiles, Mariana; Russell, Allison; McPherson, Laura; Gander, Jennifer; Pastan, Stephen

    2016-01-01

    Kidney transplantation is the preferred treatment for patients with end-stage renal disease, as it substantially increases a patient's survival and is cost saving compared to a lifetime of dialysis. However, transplantation is not universally chosen by patients with renal failure, and limited knowledge about the survival benefit of transplantation vs. dialysis may play a role. We created a mobile application clinical decision aid called iChoose Kidney to improve access to individualized prognosis information comparing dialysis and transplantation outcomes. We describe the iChoose Kidney study, a randomized controlled trial designed to test the clinical efficacy of a mobile health decision aid among end-stage renal disease patients referred for kidney transplantation at three large, diverse transplant centers across the U.S. Approximately 450 patients will be randomized to receive either: (1) standard of care or “usual” transplantation education, or (2) standard of care plus iChoose Kidney. The primary outcome is change in knowledge about the survival benefit of kidney transplantation vs. dialysis from baseline to immediate follow-up; secondary outcomes include change in treatment preferences, improved decisional conflict, and increased access to kidney transplantation. Analyses are also planned to examine effectiveness across subgroups of race, socioeconomic status, health literacy and health numeracy. Engaging patients in health care choices can increase patient empowerment and improve knowledge and understanding of treatment choices. If the effectiveness of iChoose Kidney has a greater impact on patients with low health literacy, lower socioeconomic status, and minority race, this decision aid could help reduce disparities in access to kidney transplantation. PMID:27610423

  20. European Mobile Satellite Services (EMSS): A regional system for Europe

    NASA Technical Reports Server (NTRS)

    Loisy, C.; Edin, P.; Benedicto, F. J.

    1995-01-01

    The European Space Agency is presently procuring two L-band payloads in order to promote a regional system for the provision of European Mobile Satellite Services (EMSS). These are the EMS payload on the Italsat I-F2 satellite and the LLM payload on the ARTEMIS satellite. Telecommunication system studies have been concentrating on mobile applications where full European geographical coverage is required. Potential applications include high priority Private Mobile Radio networks requiring national or European coverage, such as civil security, fire brigades, police and health services, as well as a dedicated system for provision of Air Traffic Services to the civil aviation community. A typical application is an intelligent road traffic management system combining a geographically selective traffic data collection service based on probe vehicles with a geographically selective traffic information broadcast service. Network architectures and bearer services have been developed both for data only and voice/data services. Vehicle mounted mobile transceivers using CDMA access techniques have been developed. The EMSS operational phase will start with the EMS payload in orbit in 1996 and continue with the LLM payload in 1997.

  1. Make That to Go: Re-Engineering a Web Portal for Mobile Access

    ERIC Educational Resources Information Center

    Spitzer, Stephan

    2012-01-01

    The fact that people now live in a world of abundant portable electronic devices is important to any organization that maintains a web presence, including libraries. No longer tied to a desktop, the patrons' netbooks, tablets, ebook readers, and, of course, cellphones all become potential tools for remote access to library content. About a year…

  2. Efficient Information Access for Location-Based Services in Mobile Environments

    ERIC Educational Resources Information Center

    Lee, Chi Keung

    2009-01-01

    The demand for pervasive access of location-related information (e.g., local traffic, restaurant locations, navigation maps, weather conditions, pollution index, etc.) fosters a tremendous application base of "Location Based Services (LBSs)". Without loss of generality, we model location-related information as "spatial objects" and the accesses…

  3. Mobilizing Curriculum Studies in a (Virtual) World: Open Access, Edupunks, and the Public Good

    ERIC Educational Resources Information Center

    Corrigan, Julie Ann; Ng-A-Fook, Nicholas

    2012-01-01

    Despite societal imperatives for equity--whether espoused by nation states or transnational agencies like UNESCO--current models of higher education are unequivocally failing to provide universal access. This paper seeks to explore the (cyber)spaces (un)occupied by higher education, specifically in the area of curriculum studies, arguing that the…

  4. Mobilization

    DTIC Science & Technology

    1987-01-01

    istic and romantic emotionalism that typifies this genre. Longino, James C., et al. “A Study of World War Procurement and Industrial Mobilization...States. Harrisburg, PA: Military Service Publishing Co., 1941. CARL 355.22 J72b. Written in rough prose , this World War II era document explains the

  5. Multi-Sensor Detection with Particle Swarm Optimization for Time-Frequency Coded Cooperative WSNs Based on MC-CDMA for Underground Coal Mines

    PubMed Central

    Xu, Jingjing; Yang, Wei; Zhang, Linyuan; Han, Ruisong; Shao, Xiaotao

    2015-01-01

    In this paper, a wireless sensor network (WSN) technology adapted to underground channel conditions is developed, which has important theoretical and practical value for safety monitoring in underground coal mines. According to the characteristics that the space, time and frequency resources of underground tunnel are open, it is proposed to constitute wireless sensor nodes based on multicarrier code division multiple access (MC-CDMA) to make full use of these resources. To improve the wireless transmission performance of source sensor nodes, it is also proposed to utilize cooperative sensors with good channel conditions from the sink node to assist source sensors with poor channel conditions. Moreover, the total power of the source sensor and its cooperative sensors is allocated on the basis of their channel conditions to increase the energy efficiency of the WSN. To solve the problem that multiple access interference (MAI) arises when multiple source sensors transmit monitoring information simultaneously, a kind of multi-sensor detection (MSD) algorithm with particle swarm optimization (PSO), namely D-PSO, is proposed for the time-frequency coded cooperative MC-CDMA WSN. Simulation results show that the average bit error rate (BER) performance of the proposed WSN in an underground coal mine is improved significantly by using wireless sensor nodes based on MC-CDMA, adopting time-frequency coded cooperative transmission and D-PSO algorithm with particle swarm optimization. PMID:26343660

  6. Multi-Sensor Detection with Particle Swarm Optimization for Time-Frequency Coded Cooperative WSNs Based on MC-CDMA for Underground Coal Mines.

    PubMed

    Xu, Jingjing; Yang, Wei; Zhang, Linyuan; Han, Ruisong; Shao, Xiaotao

    2015-08-27

    In this paper, a wireless sensor network (WSN) technology adapted to underground channel conditions is developed, which has important theoretical and practical value for safety monitoring in underground coal mines. According to the characteristics that the space, time and frequency resources of underground tunnel are open, it is proposed to constitute wireless sensor nodes based on multicarrier code division multiple access (MC-CDMA) to make full use of these resources. To improve the wireless transmission performance of source sensor nodes, it is also proposed to utilize cooperative sensors with good channel conditions from the sink node to assist source sensors with poor channel conditions. Moreover, the total power of the source sensor and its cooperative sensors is allocated on the basis of their channel conditions to increase the energy efficiency of the WSN. To solve the problem that multiple access interference (MAI) arises when multiple source sensors transmit monitoring information simultaneously, a kind of multi-sensor detection (MSD) algorithm with particle swarm optimization (PSO), namely D-PSO, is proposed for the time-frequency coded cooperative MC-CDMA WSN. Simulation results show that the average bit error rate (BER) performance of the proposed WSN in an underground coal mine is improved significantly by using wireless sensor nodes based on MC-CDMA, adopting time-frequency coded cooperative transmission and D-PSO algorithm with particle swarm optimization.

  7. Accessing to electronic medical history using a mobility intra hospital system.

    PubMed

    Guillén, Sergio; Traver, Vicente; Monton, Eduardo; Castellano, Elena; Valdivieso, Bernardo; Valero, Manuel Regaña

    2011-01-01

    The aim of this paper is to describe the solution that has been developed in Valencia Region (Spain) to provide health professionals (physicians and nurses) access to all the functionalities of a Hospital Information System (HIS) already available at fixed clients workstations. These functionalities are adapted to the care process carried out at patient bedside. In this way, professionals will have access to treatment and administration, recording of vital signs, nursing assessment, scales, care plan, extractions, medical records, progress notes so that they have all necessary information at the bedside, and record swiftly changes that occur in-situ. In addition, clinical safety is reinforced, including RFID patient identification mechanisms and barcode readers for blood samples or unidosis medication.

  8. Neoplastic transformation in C3H 10T(1/2) cells after exposure to 835.62 MHz FDMA and 847.74 MHz CDMA radiations.

    PubMed

    Roti Roti JL; Malyapa, R S; Bisht, K S; Ahern, E W; Moros, E G; Pickard, W F; Straube, W L

    2001-01-01

    The effect of radiofrequency (RF) radiation in the cellular phone communication range (835.62 MHz frequency division multiple access, FDMA; 847.74 MHz code division multiple access, CDMA) on neoplastic transformation frequency was measured using the in vitro C3H 10T(1/2) cell transformation assay system. To determine if 835.62 MHz FDMA or 847.74 MHz CDMA radiations have any genotoxic effects that induce neoplastic transformation, C3H 10T(1/2) cells were exposed at 37 degrees C to either of the above radiations [each at a specific absorption rate (SAR) of 0.6 W/kg] or sham-exposed at the same time for 7 days. After the culture medium was changed, the cultures were transferred to incubators and refed with fresh growth medium every 7 days. After 42 days, the cells were fixed and stained with Giemsa, and transformed foci were scored. To determine if exposure to 835.62 MHz FDMA or 847.74 MHz CDMA radiation has any epigenetic effects that can promote neoplastic transformation, cells were first exposed to 4.5 Gy of X rays to induce the transformation process and then exposed to the above radiations (SAR = 0.6 W/kg) in temperature-controlled irradiators with weekly refeeding for 42 days. After both the 7-day RF exposure and the 42-day RF exposure after X irradiation, no statistically significant differences in the transformation frequencies were observed between incubator controls, the sham-exposed (maintained in irradiators without power to the antenna), and the 835.62 MHz FDMA or 847.74 MHz CDMA-exposed groups.

  9. Code-division multiple-access multiuser demodulator by using quantum fluctuations

    NASA Astrophysics Data System (ADS)

    Otsubo, Yosuke; Inoue, Jun-ichi; Nagata, Kenji; Okada, Masato

    2014-07-01

    We examine the average-case performance of a code-division multiple-access (CDMA) multiuser demodulator in which quantum fluctuations are utilized to demodulate the original message within the context of Bayesian inference. The quantum fluctuations are built into the system as a transverse field in the infinite-range Ising spin glass model. We evaluate the performance measurements by using statistical mechanics. We confirm that the CDMA multiuser modulator using quantum fluctuations achieve roughly the same performance as the conventional CDMA multiuser modulator through thermal fluctuations on average. We also find that the relationship between the quality of the original information retrieval and the amplitude of the transverse field is somehow a "universal feature" in typical probabilistic information processing, viz., in image restoration, error-correcting codes, and CDMA multiuser demodulation.

  10. Code-division multiple-access multiuser demodulator by using quantum fluctuations.

    PubMed

    Otsubo, Yosuke; Inoue, Jun-Ichi; Nagata, Kenji; Okada, Masato

    2014-07-01

    We examine the average-case performance of a code-division multiple-access (CDMA) multiuser demodulator in which quantum fluctuations are utilized to demodulate the original message within the context of Bayesian inference. The quantum fluctuations are built into the system as a transverse field in the infinite-range Ising spin glass model. We evaluate the performance measurements by using statistical mechanics. We confirm that the CDMA multiuser modulator using quantum fluctuations achieve roughly the same performance as the conventional CDMA multiuser modulator through thermal fluctuations on average. We also find that the relationship between the quality of the original information retrieval and the amplitude of the transverse field is somehow a "universal feature" in typical probabilistic information processing, viz., in image restoration, error-correcting codes, and CDMA multiuser demodulation.

  11. Toward a Next Generation of Widely Accessible Spatial Interfaces: Mobile VR Environments for Patients with Persistent Pain

    PubMed Central

    Schroeder, David; Korsakov, Fedor; Jolton, Joseph; Keefe, Francis J.; Haley, Alex; Keefe, Daniel F.

    2015-01-01

    We present a series of multi-modal spatial interfaces and virtual environments that can be implemented with widely accessible virtual reality (VR) technologies. The results demonstrate and evaluate the new degree to which rich virtual experiences involving motion sensing, physiological inputs, stereoscopic imagery, sound, and haptic feedback can now be created using low-cost (e.g., mobile phone based) VR environments. Adapting spatial interfaces to these new platforms can open up exciting new application areas for VR. This is demonstrated through a series of prototype systems aimed at delivering in-home VR therapies to patients suffering from persistent pain conditions (e.g. arthritis pain, cancer pain). A rich spatial interface and visual aesthetic is particularly important for the success of these applications; thus an interdisciplinary team with expertise in technology, design, meditation, and the psychology of pain worked together to iteratively develop and evaluate the current prototypes. PMID:24807994

  12. History of Antenna Technology for Mobile Communications in Korea

    NASA Astrophysics Data System (ADS)

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

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

  13. A New TH-CDMA Scheme for Dispersive Infrared Channel and Its Performance Evaluation

    NASA Astrophysics Data System (ADS)

    Hamdi, Mazda; Nasiri-Kenari, Masoumeh

    2011-04-01

    Infrared indoor wireless communications using nondirected links are subject to severe multipath distortion which causes intersymbol interference (ISI). To lessen multipath distortion effect and thereby to improve the system performance, in this paper, we consider a new time-hopping based multiple access scheme for this channel, in which one pulse is transmitted in each bit interval. The position of the pulse is determined based on the output of a low rate error correcting code along with the user's dedicated PN code. We evaluate the multiple access performance of the system for correlation receiver considering background noise, dark current, and thermal noise. We compare the performance of our proposed multiple access scheme with those of the previously introduced code division multiple access schemes for infrared communications, like CDMA and Frame Time Hopping (FTH). Our results show that, for the same bandwidth and bit rate, the proposed system substantially excels the other methods in term of bit error rate, or equivalently the number of the users supported at a fixed bit error rate.

  14. Multiple user access and testing for PreNotiS: a fast mobile event reporting solution

    NASA Astrophysics Data System (ADS)

    Chan, Michael; Kumar, Abhinav; Akopian, David; Agaian, Sos S.

    2011-06-01

    The PreNotiS (preventive notification system) was proposed to address the current lack in consumer prevention and disaster informatics systems. The underscore of this letter is to propose PreNotiS as a provision of trusted proxies of information sourcing to be integral to the disaster informatics framework. To promote loose coupling among subsystems, PreNotiS has evolved into a model-view-controller (MVC) architecture via object-oriented incremental prototyping. The MVC specifies how all subsystems and how they interact with each other. A testing framework is also proposed for the PreNotiS to verify multiple concurrent user access which might be observable during disasters. The framework relies on conceptually similar self-test modules to help with serviceability.

  15. Grand Canyon as a universally accessible virtual field trip for intro Geoscience classes using geo-referenced mobile game technology

    NASA Astrophysics Data System (ADS)

    Bursztyn, N.; Pederson, J. L.; Shelton, B.

    2012-12-01

    There is a well-documented and nationally reported trend of declining interest, poor preparedness, and lack of diversity within U.S. students pursuing geoscience and other STEM disciplines. We suggest that a primary contributing factor to this problem is that introductory geoscience courses simply fail to inspire (i.e. they are boring). Our experience leads us to believe that the hands-on, contextualized learning of field excursions are often the most impactful component of lower division geoscience classes. However, field trips are becoming increasingly more difficult to run due to logistics and liability, high-enrollments, decreasing financial and administrative support, and exclusivity of the physically disabled. Recent research suggests that virtual field trips can be used to simulate this contextualized physical learning through the use of mobile devices - technology that exists in most students' hands already. Our overarching goal is to enhance interest in introductory geoscience courses by providing the kinetic and physical learning experience of field trips through geo-referenced educational mobile games and test the hypothesis that these experiences can be effectively simulated through virtual field trips. We are doing this by developing "serious" games for mobile devices that deliver introductory geology material in a fun and interactive manner. Our new teaching strategy will enhance undergraduate student learning in the geosciences, be accessible to students of diverse backgrounds and physical abilities, and be easily incorporated into higher education programs and curricula at institutions globally. Our prototype involves students virtually navigating downstream along a scaled down Colorado River through Grand Canyon - physically moving around their campus quad, football field or other real location, using their smart phone or a tablet. As students reach the next designated location, a photo or video in Grand Canyon appears along with a geological

  16. Enabling All-Access Mobility for Planetary Exploration Vehicles via Transformative Reconfiguration

    NASA Technical Reports Server (NTRS)

    Ferguson, Scott; Mazzoleni, Andre

    2016-01-01

    Effective large-scale exploration of planetary surfaces requires robotic vehicles capable of mobility across chaotic terrain. Characterized by a combination of ridges, cracks and valleys, the demands of this environment can cause spacecraft to experience significant reductions in operating footprint, performance, or even result in total system loss. Significantly increasing the scientific return of an interplanetary mission is facilitated by architectures capable of real-time configuration changes that go beyond that of active suspensions while concurrently meeting system, mass, power, and cost constraints. This Phase 1 report systematically explores how in-service architecture changes can expand system capabilities and mission opportunities. A foundation for concept generation is supplied by four Martian mission profiles spanning chasms, ice fields, craters and rocky terrain. A fifth mission profile centered on Near Earth Object exploration is also introduced. Concept generation is directed using four transformation principles - a taxonomy developed by the engineering design community to explain the cause of an architecture change and existing brainstorming techniques. This allowed early conceptual sketches of architecture changes to be organized by the principle driving the greatest increase in mission performance capability.

  17. A Simple Exact Error Rate Analysis for DS-CDMA with Arbitrary Pulse Shape in Flat Nakagami Fading

    NASA Astrophysics Data System (ADS)

    Rahman, Mohammad Azizur; Sasaki, Shigenobu; Kikuchi, Hisakazu; Harada, Hiroshi; Kato, Shuzo

    A simple exact error rate analysis is presented for random binary direct sequence code division multiple access (DS-CDMA) considering a general pulse shape and flat Nakagami fading channel. First of all, a simple model is developed for the multiple access interference (MAI). Based on this, a simple exact expression of the characteristic function (CF) of MAI is developed in a straight forward manner. Finally, an exact expression of error rate is obtained following the CF method of error rate analysis. The exact error rate so obtained can be much easily evaluated as compared to the only reliable approximate error rate expression currently available, which is based on the Improved Gaussian Approximation (IGA).

  18. Usability evaluation: results from "Evaluation of mobile information technology to improve nurses' access to and use of research evidence".

    PubMed

    Di Pietro, Tammie Leigh; Nguyen, Ha; Doran, Diane M

    2012-08-01

    Usability evaluations are necessary to determine the feasibility of nurses' interactions with computerized clinical decision-support systems. Limitations and challenges of operations that inhibit or facilitate utilization in clinical practice can be identified. This study provided nurses with mobile information terminals, PDAs and tablet PCs, to improve point-of-care access to information. The purpose of this study was to determine usability issues associated with point-of-care technology. Eleven nurses were self-selected. Nurses were videotaped and audiotaped completing four tasks, including setting up the device and three resource search exercises. A research team member completed a usability checklist. Completion times for each task, success rate, and challenges experienced were documented. Four participants completed all tasks, with an average time of 3 minutes 22 seconds. Three participants were unable to complete any of the three tasks. Navigating within resources caused the greatest occurrence of deviations with 39 issues among all participants. Results of the usability evaluation suggest that nurses require a device that (1) is manageable to navigate and (2) utilizes a user-friendly interface, such as a one-time log-in system. Usability testing can be helpful to organizations as they document issues to be cognizant of during the implementation process, increasing the potential for successful implementation and sustained usability.

  19. A Comparison of Mobile and Fixed Device Access on User Engagement Associated With Women, Infants, and Children (WIC) Online Nutrition Education

    PubMed Central

    2016-01-01

    Background Online health education has expanded its reach due to cost-effective implementation and demonstrated effectiveness. However, a limitation exists with the evaluation of online health education implementations and how the impact of the system is attenuated by the extent to which a user engages with it. Moreover, the current online health education research does not consider how this engagement has been affected by the transition from fixed to mobile user access over the last decade. Objective This paper focuses on comparing the impact mobile versus fixed devices have on user engagement key performance indicators (KPI) associated with the wichealth website (.org), an Internet-based parent-child feeding intervention offered to clients associated with the US Department of Agriculture’s Special Supplemental Nutrition Program for Women, Infants, and Children (WIC). Methods Data were collected from 612,201 nutrition education lessons completed by 305,735 unique WIC participants in 21 states over a 1-year period. Data consisted of system-collected measures, profile items, and items from an exit survey administered at the conclusion of each lesson. User engagement was defined based on 3 KPIs associated with usage of the wichealth website: number of link views, link view time, and progression in stage of readiness to change. Independent samples t tests were used to compare KPIs between fixed only and mobile only device users and paired samples t tests were used to compare KPIs within users who completed at least one lesson each on both a fixed and mobile device. A logistic regression was performed to estimate the odds of KPI performance thresholds in the independent samples study group given access device type while controlling for confounding of user characteristics associated with these KPIs. Results Analysis of 8 user characteristics (lessons completed, race, ethnicity, language, state of residence, pregnancy status, beginning stage of change, and preferred

  20. A Wideband Satcom Based Avionics Network with CDMA Uplink and TDM Downlink

    NASA Technical Reports Server (NTRS)

    Agrawal, D.; Johnson, B. S.; Madhow, U.; Ramchandran, K.; Chun, K. S.

    2000-01-01

    The purpose of this paper is to describe some key technical ideas behind our vision of a future satcom based digital communication network for avionics applications The key features of our design are as follows: (a) Packetized transmission to permit efficient use of system resources for multimedia traffic; (b) A time division multiplexed (TDM) satellite downlink whose physical layer is designed to operate the satellite link at maximum power efficiency. We show how powerful turbo codes (invented originally for linear modulation) can be used with nonlinear constant envelope modulation, thus permitting the satellite amplifier to operate in a power efficient nonlinear regime; (c) A code division multiple access (CDMA) satellite uplink, which permits efficient access to the satellite from multiple asynchronous users. Closed loop power control is difficult for bursty packetized traffic, especially given the large round trip delay to the satellite. We show how adaptive interference suppression techniques can be used to deal with the ensuing near-far problem; (d) Joint source-channel coding techniques are required both at the physical and the data transport layer to optimize the end-to-end performance. We describe a novel approach to multiple description image encoding at the data transport layer in this paper.

  1. Improved Channel Allocation for Multicarrier CDMA with Adaptive Frequency Hopping and Multiuser Detection

    DTIC Science & Technology

    2008-08-29

    Areas Commun., vol. 14, pp. 1852-1858, Dec. 1996. [6] Y. H. Kim, I. Song, S. Yoon and S. R. Park, “A multicarrier CDMA system with adaptive subchannel ...J. Li, and Z. Cao, “A near optimal subchannel allocation policy in forward links for multicarrier CDMA system,” Proc. IEEE VTC, 2001-Spring, vol. 2...Rhodes, Greece, 2001, pp. 896-900. [10] T. Jia, and A. Duel-Hallen, “ Subchannel allocation for multicarrier CDMA with adaptive frequency hopping

  2. Comparison of hybrid FDMA/CDMA systems in frequency selective Rayleigh fading

    NASA Astrophysics Data System (ADS)

    Eng, Thomas; Milstein, Laurence B.

    1994-06-01

    A hybrid FDMA/CDMA scheme operating over a frequency selective Rayleigh fading channel is described and analyzed. The performance of the hybrid system is then compared with that of a wideband CDMA system occupying the same total bandwidth. Both coherent and noncoherent modulation formats are investigated; it is found that, for coherent modulation with a RAKE receiver, wideband CDMA has greater capacity than does the hybrid. However, for the noncoherent modulation formats (either DPSK or square-law detected orthogonal signaling), a hybrid system can have a greater capacity if a high channel error rate can be tolerated. Otherwise, a wideband noncoherent system remains optimal.

  3. The introduction and evaluation of mobile devices to improve access to patient records: a catalyst for innovation and collaboration at BCCA.

    PubMed

    Wu, Jonn; Waldron, John; Hood, Shaina; Kahnamelli, Adam; Khan, Mohamed; Barnett, Jeff; French, John; Slager, Stacey; Melhem, Shadi; Shabestari, Omid

    2013-01-01

    Prompt and efficient access to patient records is vital in providing optimal patient care. The Cancer Agency Information System (CAIS) is the primary patient record repository for the British Columbia Cancer Agency (BCCA) but is only accessible on traditional computer workstations. The BCCA clinics have significant space limitations resulting in multiple health care professionals sharing each workstation. Furthermore, workstations are not available in examination rooms. A novel and cost efficient solution is necessary to improve clinician access to CAIS. This prompted the BCCA and IMITS to embark on an innovative provincial collaboration to introduce and evaluate the impact of a mobile device to improve access to CAIS. The project consisted of 2 phases with over 50 participants from multiple clinical disciplines across BCCA sites. Phase I evaluated the adoptability, effectiveness and costs associated with providing access to CAIS using a generic viewer (Citrix). Phase II incorporated the feedback and findings from Phase I to make available a customized mobile device-specific application. Phase II also addressed privacy and security requirements.

  4. Ultrahigh-capacity access network architecture for mobile data backhaul using integrated W-band wireless and free-space optical links with OAM multiplexing.

    PubMed

    Fang, Yuan; Yu, Jianjun; Zhang, Junwen; Chi, Nan; Xiao, Jiangnan; Chang, Gee-Kung

    2014-07-15

    In this Letter, we propose and experimentally demonstrate a novel access network architecture using hybrid integrated W-band wireless and free-space optical (FSO) links with orbital angular momentum (OAM) multiplexing. The transmission of a 20 GBd quadrature phase-shift keying signal modulated over 10 OAM modes has been demonstrated over a 0.6 m FSO link and a 0.4 m W-band wireless link at 100 GHz. The experimental results show that the architecture can support future ultrahigh-capacity, converged optical-wireless access networks that require extra bandwidth and system flexibility in mobile data networks.

  5. Bit-Error-Rate Performance of a Gigabit Ethernet O-CDMA Technology Demonstrator (TD)

    SciTech Connect

    Hernandez, V J; Mendez, A J; Bennett, C V; Lennon, W J

    2004-07-09

    An O-CDMA TD based on 2-D (wavelength/time) codes is described, with bit-error-rate (BER) and eye-diagram measurements given for eight users. Simulations indicate that the TD can support 32 asynchronous users.

  6. Code division multiple-access techniques in optical fiber networks. II - Systems performance analysis

    NASA Astrophysics Data System (ADS)

    Salehi, Jawad A.; Brackett, Charles A.

    1989-08-01

    A technique based on optical orthogonal codes was presented by Salehi (1989) to establish a fiber-optic code-division multiple-access (FO-CDMA) communications system. The results are used to derive the bit error rate of the proposed FO-CDMA system as a function of data rate, code length, code weight, number of users, and receiver threshold. The performance characteristics for a variety of system parameters are discussed. A means of reducing the effective multiple-access interference signal by placing an optical hard-limiter at the front end of the desired optical correlator is presented. Performance calculations are shown for the FO-CDMA with an ideal optical hard-limiter, and it is shown that using a optical hard-limiter would, in general, improve system performance.

  7. The effect of chronic exposure to 835.62 MHz FDMA or 847.74 MHz CDMA radiofrequency radiation on the incidence of spontaneous tumors in rats.

    PubMed

    La Regina, Marie; Moros, Eduardo G; Pickard, William F; Straube, William L; Baty, Jack; Roti Roti, Joseph L

    2003-08-01

    This study was designed to determine whether chronic exposure to radiofrequency (RF) radiation from cellular phones increased the incidence of spontaneous tumors in F344 rats. Eighty male and 80 female rats were randomly placed in each of three irradiation groups. The sham group received no irradiation; the Frequency Division Multiple Access (FDMA) group was exposed to 835.62 MHz FDMA RF radiation; and the Code Division Multiple Access (CDMA) group was exposed to 847.74 MHz CDMA RF radiation. Rats were irradiated 4 h per day, 5 days per week over 2 years. The nominal time-averaged specific absorption rate (SAR) in the brain for the irradiated animals was 0.85 +/- 0.34 W/kg (mean +/- SD) per time-averaged watt of antenna power. Antennas were driven with a time-averaged power of 1.50 +/- 0.25 W (range). That is, the nominal time-averaged brain SAR was 1.3 +/- 0.5 W/kg (mean +/- SD). This number was an average from several measurement locations inside the brain, and it takes into account changes in animal weight and head position during irradiation. All major organs were evaluated grossly and histologically. The number of tumors, tumor types and incidence of hyperplasia for each organ were recorded. There were no significant differences among final body weights or survival days for either males or females in any group. No significant differences were found between treated and sham-exposed animals for any tumor in any organ. We conclude that chronic exposure to 835.62 MHz FDMA or 847.74 MHz CDMA RF radiation had no significant effect on the incidence of spontaneous tumors in F344 rats.

  8. Improved CDMA Performance Using Parallel Interference Cancellation

    NASA Technical Reports Server (NTRS)

    Simon, Marvin; Divsalar, Dariush

    1995-01-01

    This report considers a general parallel interference cancellation scheme that significantly reduces the degradation effect of user interference but with a lesser implementation complexity than the maximum-likelihood technique. The scheme operates on the fact that parallel processing simultaneously removes from each user the interference produced by the remaining users accessing the channel in an amount proportional to their reliability. The parallel processing can be done in multiple stages. The proposed scheme uses tentative decision devices with different optimum thresholds at the multiple stages to produce the most reliably received data for generation and cancellation of user interference. The 1-stage interference cancellation is analyzed for three types of tentative decision devices, namely, hard, null zone, and soft decision, and two types of user power distribution, namely, equal and unequal powers. Simulation results are given for a multitude of different situations, in particular, those cases for which the analysis is too complex.

  9. 76 FR 32901 - The Provision of Fixed and Mobile Broadband Access, Educational and Other Advanced Services in...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-06-07

    ... subscriber station and base station with a typical cell radius of 3 to 10 kilometers. WiMAX can support fixed... satellite service (MSS) system with the downlink (satellite to mobile earth stations) in the 2483.5-2500 MHz... of 6 MHz or the actual emission bandwidth as defined in Sec. 27.53(m)(6). Mobile Satellite...

  10. Peak power minimization in indoor CDMA communications using clusters of antennas

    NASA Astrophysics Data System (ADS)

    Abolhassani, Bahman

    "Battery life" and "cost" constraints are presenting new challenges for the design of wireless networks. The major focus of past research on transmit power control, diversity, modulation and coding techniques has been limited to maximizing coverage and/or capacity for cellular telephone systems. However, for battery powered wireless handsets connected through indoor wireless links, the optimization objective is shifting from link efficiency to battery efficiency and cost. In this thesis, the battery life of handsets and the cost of network are both addressed for an indoor code division multiple access (CDMA) communications system using time division duplex (TDD). A wireless handset needs a large dynamic range transmitter amplifier in order to overcome channel path loss and fading. This makes the amplifier inefficient such that its power consumption becomes proportional to the peak transmit power. Therefore, the amplifier needs a large, heavy and expensive battery which lasts for only a few hours. Indoor wireless users, however, need small, light, low cost handsets with batteries that last for days rather than for a few hours. To achieve a long battery life for handsets, a system architecture is proposed in which each cell uses a central base station along with several radioports. The radioports placed at optimal or near-optimal locations in order to minimize the maximum path loss experienced by handsets. Each radioport may use more than one antenna to combat Rayleigh fading. The central base station selects the radioport that provides the strongest maximally ratio combined signal. An infra-structure cost model is developed for the proposed system, which depends on the peak transmit power capability of handsets and of other system parameters and performances. The number of parameters affecting the network infra-structure cost is high, which makes the cost minimization problematic. To avoid large computation time, a new network planning approach is proposed: its

  11. Contextual Uncertainties, Human Mobility, and Perceived Food Environment: The Uncertain Geographic Context Problem in Food Access Research.

    PubMed

    Chen, Xiang; Kwan, Mei-Po

    2015-09-01

    We examined the uncertainty of the contextual influences on food access through an analytic framework of the uncertain geographic context problem (UGCoP). We first examined the compounding effects of two kinds of spatiotemporal uncertainties on people's everyday efforts to procure food and then outlined three key dimensions (food access in real time, temporality of the food environment, and perceived nutrition environment) in which research on food access must improve to better represent the contributing environmental influences that operate at the individual level. Guidelines to address the UGCoP in future food access research are provided to account for the multidimensional influences of the food environment on dietary behaviors.

  12. Performance evaluation of CCI on the forward CDMA channel

    NASA Astrophysics Data System (ADS)

    Alam, M. S.; Alsharif, S.; Hossain, A. H. M. Z.

    2013-05-01

    This paper focuses on the performance of cochannel interference (CCI) which is the primary factor to limit the capacity of wireless communication systems. Several cellular network architectures have been proposed in the literature to reduce the cochannel interference, but none of them appears to effectively tackle this problem. Microzoning is the technique, where the cells are further divided into smaller zones. The advantage of this technique is that the cochannel interference in the cellular system is reduced because the cell maintains a particular coverage radius. The objective of this paper is to analyze the performance of cochannel interference on the forward channels of the proposed microzone based CDMA cellular systems operating with perfect power control in an effort to reduce the cochannel interference. Simulation results showed that the proposed technique can effectively minimize cochannel interference and the proposed architecture can be used for practical applications.

  13. Performance evaluation of CCI on the reverse CDMA channel

    NASA Astrophysics Data System (ADS)

    Alam, M. S.; Alsharif, S.; Hossain, A. H. M. Z.

    2011-06-01

    This paper focuses on the performance of cochannel interference (CCI) which is the primary factor to limit the capacity of wireless communication systems. Several cellular network architectures have been proposed in the literature to reduce the cochannel interference, but none of them appears to effectively tackle this problem. Microzoning is the technique, where the cells are further divided into smaller zones. The advantage of this technique is that the cochannel interference in the cellular system is reduced because the cell maintains a particular coverage radius. The objective of this paper is to analyze the performance of cochannel interference on the reverse channels of the proposed microzone based CDMA cellular systems operating with perfect power control in an effort to reduce the cochannel interference. Simulation results showed that the proposed technique can effectively minimize cochannel interference and the proposed architecture can be used for practical applications.

  14. A new watermarking approach based on combination of reversible watermarking and CDMA in spatial and DWT domain

    NASA Astrophysics Data System (ADS)

    Bekkouche, S.; Chouarfia, A.

    2011-06-01

    Image watermarking can be defined as a technique that allows insertion of imperceptible and indelible digital data into an image. In addition to its initial application which is the copyright, watermarking can be used in other fields, particularly in the medical field in order to contribute to secure images shared on the network for telemedicine applications. In this report we study some watermarking methods and the comparison result of their combination, the first one is based on the CDMA (Code Division Multiple Access) in DWT and spatial domain and its aim is to verify the image authenticity whereas the second one is the reversible watermarking (the least significant bits LSB and cryptography tools) and the reversible contrast mapping RCM its objective is to check the integrity of the image and to keep the Confidentiality of the patient data. A new scheme of watermarking is the combination of the reversible watermarking method based on LSB and cryptography tools and the method of CDMA in spatial and DWT domain to verify the three security properties Integrity, Authenticity and confidentiality of medical data and patient information .In the end ,we made a comparison between these methods within the parameters of quality of medical images. Initially, an in-depth study on the characteristics of medical images would contribute to improve these methods to mitigate their limits and to optimize the results. Tests were done on IRM kind of medical images and the quality measurements have been done on the watermarked image to verify that this technique does not lead to a wrong diagnostic. The robustness of the watermarked images against attacks has been verified on the parameters of PSNR, SNR, MSE and MAE which the experimental result demonstrated that the proposed algorithm is good and robust in DWT than in spatial domain.

  15. Distributed reservation-based code division multiple access

    NASA Astrophysics Data System (ADS)

    Wieselthier, J. E.; Ephremides, A.

    1984-11-01

    The use of spread spectrum signaling, motivated primarily by its antijamming capabilities in military applications, leads naturally to the use of Code Division Multiple Access (CDMA) techniques that permit the successful simultaneous transmission by a number of users over a wideband channel. In this paper we address some of the major issues that are associated with the design of multiple access protocols for spread spectrum networks. We then propose, analyze, and evaluate a distributed reservation-based multiple access protocol that does in fact exploit CDMA properties. Especially significant is the fact that no acknowledgment or feedback information from the destination is required (thus facilitating communication with a radio-silent mode), nor is any form of coordination among the users necessary.

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

    PubMed

    He, Longjun; Ming, Xing; Liu, Qian

    2014-04-01

    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 reconstruction and direct volume rendering, to providing shape, brightness, depth and location information generated from the original sectional images for radiologists. Furthermore, an algorithm that changes remote render parameters automatically to adapt to the network status was employed to improve the quality of experience. Finally, performance issues regarding the remote 3D visualization of the medical images over the wireless network of the proposed application were also discussed. The results demonstrated that this proposed medical application could provide a smooth interactive experience in the WLAN and 3G networks.

  17. [Abnormal catheter mobility in a totally implantable venous access depending on the upright or supine position in an obese patient].

    PubMed

    Bernard, P; Vrignaud, S; Letessier, E; Denimal, F; Le Néel, J C

    2001-10-01

    The authors advise on an exceptional complication in a totally implantable venous access and give recommendations on how to avoid this problem. In an obese person, one week after the implantation of a totally implantable venous access, a chest X-ray showed that the catheter was too short. In the operative room, at the time of the second intervention, the radioscopy did not find this anomaly. The subcutaneous injection port was positioned too low. When the patient was in a supine position, the subcutaneous injection port was in the correct position but when she was in an upright position, the breast descended and pulled down the subcutaneous injection port and the catheter.

  18. High precision three-dimensional iterative indoor localization algorithm using code division multiple access modulation based on visible light communication

    NASA Astrophysics Data System (ADS)

    Guan, Weipeng; Wu, Yvxiang; Wen, Shangsheng; Yang, Chen; Chen, Hao; Zhang, Zhaoze; Chen, Yingcong

    2016-10-01

    To solve the problem of positioning accuracy affected by mutual interference among multiple reference points in the traditional visible light communication positioning system, an iterative algorithm of received signal strength (RSS) based on code division multiple access (CDMA) coding is proposed. Every light-emitting diode (LED) source broadcasts a unique CDMA modulation identification (ID) code, which is associated with geographic position. The mobile terminal receives a mixed light signal from each LED reference point. By using the orthogonality of the spreading codes, the corresponding ID position information and the intensity attenuation factor of each LED reference point source can be available. According to the ID information and signal attenuation intensity, the location area of each LED and the distance between the receiver end and each LED can be determined. The three-dimensional (3-D) position of the receiver can be obtained by using the iterative algorithm of RSS triangulation. The experimental results show that the proposed algorithm can achieve a positioning accuracy of 5.25 cm in a two-dimensional (2-D) positioning system. And in the 3-D positioning system, the maximum positioning error is 10.27 cm, the minimum positioning error is 0.45 cm, the average positioning error is 3.97 cm, and the proportion of the positioning error exceeding 5 cm is <25%. With a very good positioning accuracy, this system is simple and does not require synchronization processing. What is more, it can be applied to both the 2-D and 3-D localization systems, which has a broad application prospect.

  19. Dynamic quality of service differentiation using fixed code weight in optical CDMA networks

    NASA Astrophysics Data System (ADS)

    Kakaee, Majid H.; Essa, Shawnim I.; Abd, Thanaa H.; Seyedzadeh, Saleh

    2015-11-01

    The emergence of network-driven applications, such as internet, video conferencing, and online gaming, brings in the need for a network the environments with capability of providing diverse Quality of Services (QoS). In this paper, a new code family of novel spreading sequences, called a Multi-Service (MS) code, has been constructed to support multiple services in Optical- Code Division Multiple Access (CDMA) system. The proposed method uses fixed weight for all services, however reducing the interfering codewords for the users requiring higher QoS. The performance of the proposed code is demonstrated using mathematical analysis. It shown that the total number of served users with satisfactory BER of 10-9 using NB=2 is 82, while they are only 36 and 10 when NB=3 and 4 respectively. The developed MS code is compared with variable-weight codes such as Variable Weight-Khazani Syed (VW-KS) and Multi-Weight-Random Diagonal (MW-RD). Different numbers of basic users (NB) are used to support triple-play services (audio, data and video) with different QoS requirements. Furthermore, reference to the BER of 10-12, 10-9, and 10-3 for video, data and audio, respectively, the system can support up to 45 total users. Hence, results show that the technique can clearly provide a relative QoS differentiation with lower value of basic users can support larger number of subscribers as well as better performance in terms of acceptable BER of 10-9 at fixed code weight.

  20. Performance of a space-time block coded code division multiple access system over Nakagami-m fading channels

    NASA Astrophysics Data System (ADS)

    Yu, Xiangbin; Dong, Tao; Xu, Dazhuan; Bi, Guangguo

    2010-09-01

    By introducing an orthogonal space-time coding scheme, multiuser code division multiple access (CDMA) systems with different space time codes are given, and corresponding system performance is investigated over a Nakagami-m fading channel. A low-complexity multiuser receiver scheme is developed for space-time block coded CDMA (STBC-CDMA) systems. The scheme can make full use of the complex orthogonality of space-time block coding to simplify the high decoding complexity of the existing scheme. Compared to the existing scheme with exponential decoding complexity, it has linear decoding complexity. Based on the performance analysis and mathematical calculation, the average bit error rate (BER) of the system is derived in detail for integer m and non-integer m, respectively. As a result, a tight closed-form BER expression is obtained for STBC-CDMA with an orthogonal spreading code, and an approximate closed-form BER expression is attained for STBC-CDMA with a quasi-orthogonal spreading code. Simulation results show that the proposed scheme can achieve almost the same performance as the existing scheme with low complexity. Moreover, the simulation results for average BER are consistent with the theoretical analysis.

  1. Enabling Web-Based GIS Tools for Internet and Mobile Devices To Improve and Expand NASA Data Accessibility and Analysis Functionality for the Renewable Energy and Agricultural Applications

    NASA Astrophysics Data System (ADS)

    Ross, A.; Stackhouse, P. W.; Tisdale, B.; Tisdale, M.; Chandler, W.; Hoell, J. M., Jr.; Kusterer, J.

    2014-12-01

    The NASA Langley Research Center Science Directorate and Atmospheric Science Data Center have initiated a pilot program to utilize Geographic Information System (GIS) tools that enable, generate and store climatological averages using spatial queries and calculations in a spatial database resulting in greater accessibility of data for government agencies, industry and private sector individuals. The major objectives of this effort include the 1) Processing and reformulation of current data to be consistent with ESRI and openGIS tools, 2) Develop functions to improve capability and analysis that produce "on-the-fly" data products, extending these past the single location to regional and global scales. 3) Update the current web sites to enable both web-based and mobile application displays for optimization on mobile platforms, 4) Interact with user communities in government and industry to test formats and usage of optimization, and 5) develop a series of metrics that allow for monitoring of progressive performance. Significant project results will include the the development of Open Geospatial Consortium (OGC) compliant web services (WMS, WCS, WFS, WPS) that serve renewable energy and agricultural application products to users using GIS software and tools. Each data product and OGC service will be registered within ECHO, the Common Metadata Repository, the Geospatial Platform, and Data.gov to ensure the data are easily discoverable and provide data users with enhanced access to SSE data, parameters, services, and applications. This effort supports cross agency, cross organization, and interoperability of SSE data products and services by collaborating with DOI, NRCan, NREL, NCAR, and HOMER for requirements vetting and test bed users before making available to the wider public.

  2. Demonstration of end-to-end cloud-DSL with a PON-based fronthaul supporting 5.76-Gb/s throughput with 48 eCDMA-encoded 1024-QAM discrete multi-tone signals.

    PubMed

    Fang, Liming; Zhou, Lei; Liu, Xiang; Zhang, Xiaofeng; Sui, Meng; Effenberger, Frank; Zhou, Jun

    2015-05-18

    We experimentally demonstrate an end-to-end ultra-broadband cloud-DSL network using passive optical network (PON) based fronthaul with electronic code-division-multiple-access (eCDMA) encoding and decoding. Forty-eight signals that are compliant with the very-high-bit-rate digital subscriber line 2 (VDSL2) standard are transmitted with a record throughput of 5.76 Gb/s over a hybrid link consisting of a 20-km standard single-mode fiber and a 100-m twisted pair.

  3. Gene expression does not change significantly in C3H 10T(1/2) cells after exposure to 847.74 CDMA or 835.62 FDMA radiofrequency radiation.

    PubMed

    Whitehead, T D; Moros, E G; Brownstein, B H; Roti Roti, J L

    2006-06-01

    In vitro experiments with C3H 10T(1/2) mouse cells were performed to determine whether Frequency Division Multiple Access (FDMA) or Code Division Multiple Access (CDMA) modulated radiofrequency (RF) radiations induce changes in gene expression. After the cells were exposed to either modulation for 24 h at a specific absorption rate (SAR) of 5 W/ kg, RNA was extracted from both exposed and sham-exposed cells for gene expression analysis. As a positive control, cells were exposed to 0.68 Gy of X rays and gene expression was evaluated 4 h after exposure. Gene expression was evaluated using the Affymetrix U74Av2 GeneChip to detect changes in mRNA levels. Each exposure condition was repeated three times. The GeneChip data were analyzed using a two-tailed t test, and the expected number of false positives was estimated from t tests on 20 permutations of the six sham RF-field-exposed samples. For the X-ray-treated samples, there were more than 90 probe sets with expression changes greater than 1.3-fold beyond the number of expected false positives. Approximately one-third of these genes had previously been reported in the literature as being responsive to radiation. In contrast, for both CDMA and FDMA radiation, the number of probe sets with an expression change greater than 1.3-fold was less than or equal to the expected number of false positives. Thus the 24-h exposures to FDMA or CDMA RF radiation at 5 W/kg had no statistically significant effect on gene expression.

  4. Unequal error protection codes for wavelet video transmission over W-CDMA, AWGN, and Rayleigh fading channels

    NASA Astrophysics Data System (ADS)

    Le, Minh Hung; Liyana-Pathirana, Ranjith

    2003-06-01

    The unequal error protection (UEP) codes with wavelet-based algorithm for video compression over wide-band code division multiple access (W-CDMA), additive white Gaussian noise (AWGN) and Rayleigh fading channels are analysed. The utilization of Wavelets has come out to be a powerful method for compress video sequence. The wavelet transform compression technique has shown to be more appropriate to high quality video applications, producing better quality output for the compressed frames of video. A spatially scalable video coding framework of MPEG2 in which motion correspondences between successive video frames are exploited in the wavelet transform domain. The basic motivation for our coder is that motion fields are typically smooth that can be efficiently captured through a multiresolutional framework. Wavelet decomposition is applied to video frames and the coefficients at each level are predicted from the coarser level through backward motion compensation. The proposed algorithms of the embedded zero-tree wavelet (EZW) coder and the 2-D wavelet packet transform (2-D WPT) are investigated.

  5. Bringing care to the community: expanding access to health care in rural Malawi through mobile health clinics.

    PubMed

    Geoffroy, E; Harries, A D; Bissell, K; Schell, E; Bvumbwe, A; Tayler-Smith, K; Kizito, W

    2014-12-21

    Cadre : Le Mialawi soufre d'un manque chronique de personnel de santé, d'un lourd fardeau d'infection au virus de l'mmuodéficience humaine (VIH) et de paludisme avec une population surtout rurale. Des unités de santé mobiles (MHCs) pourraient fournir des soins de santé primaires aux adultes et aux enfants dans les zones d'accès difficile.Objectifs : Déterminer la faisabilité, le volume et les types de services fournis par trois MHCs de 2011 à 2013 dans le district de Mulanje, Malawi.Schéma : Etude rétrospective transversale.Résultats : Les MHCs ont effectué 309 492 consultations de soins de santé primaires et en 2013, les services ont fonctionné pendant 99% des jours prévus. En dépit d'une amélioration dans la fourniture des services, le total des consultations de patients a décliné au cours de la période d'étude. Le paludisme et les problèmes respiratoires et gastro-intestinaux constituaient 60% des consultations. Les femmes étaient significativement plus nombreuses (n = 11 543) que les hommes (n = 2481) à avoir un test VIH, mais les hommes étaient plus souvent VIH positifs (27%) que les femmes (14%). Le paludisme représentait 26 421 (35%) consultations pour les enfants de moins de 5 ans avec une augmentation significative en saison des pluies. La mise en œuvre des tests de diagnostic rapide a été associée à un déclin du nombre de patients traités pour paludisme. Les ruptures de stock d'antibiotiques dans les centres de santé du gouvernement étaient associés à une augmentation des consultations des MHC.Conclusion : Les MHC peuvent offrir en routine des soins de santé primaires aux adultes et aux enfants vivant dans les zones rurales du Malawi et compléter les structures fixes. Mais passer d'un rôle de complément à l'intégration au sein du système de santé du gouvernement reste un défi.

  6. Democratizing Neurorehabilitation: How Accessible are Low-Cost Mobile-Gaming Technologies for Self-Rehabilitation of Arm Disability in Stroke?

    PubMed Central

    Rinne, Paul; Mace, Michael; Nakornchai, Tagore; Zimmerman, Karl; Fayer, Susannah; Sharma, Pankaj; Liardon, Jean-Luc; Burdet, Etienne; Bentley, Paul

    2016-01-01

    Motor-training software on tablets or smartphones (Apps) offer a low-cost, widely-available solution to supplement arm physiotherapy after stroke. We assessed the proportions of hemiplegic stroke patients who, with their plegic hand, could meaningfully engage with mobile-gaming devices using a range of standard control-methods, as well as by using a novel wireless grip-controller, adapted for neurodisability. We screened all newly-diagnosed hemiplegic stroke patients presenting to a stroke centre over 6 months. Subjects were compared on their ability to control a tablet or smartphone cursor using: finger-swipe, tap, joystick, screen-tilt, and an adapted handgrip. Cursor control was graded as: no movement (0); less than full-range movement (1); full-range movement (2); directed movement (3). In total, we screened 345 patients, of which 87 satisfied recruitment criteria and completed testing. The commonest reason for exclusion was cognitive impairment. Using conventional controls, the proportion of patients able to direct cursor movement was 38–48%; and to move it full-range was 55–67% (controller comparison: p>0.1). By comparison, handgrip enabled directed control in 75%, and full-range movement in 93% (controller comparison: p<0.001). This difference between controllers was most apparent amongst severely-disabled subjects, with 0% achieving directed or full-range control with conventional controls, compared to 58% and 83% achieving these two levels of movement, respectively, with handgrip. In conclusion, hand, or arm, training Apps played on conventional mobile devices are likely to be accessible only to mildly-disabled stroke patients. Technological adaptations such as grip-control can enable more severely affected subjects to engage with self-training software. PMID:27706248

  7. Democratizing Neurorehabilitation: How Accessible are Low-Cost Mobile-Gaming Technologies for Self-Rehabilitation of Arm Disability in Stroke?

    PubMed

    Rinne, Paul; Mace, Michael; Nakornchai, Tagore; Zimmerman, Karl; Fayer, Susannah; Sharma, Pankaj; Liardon, Jean-Luc; Burdet, Etienne; Bentley, Paul

    2016-01-01

    Motor-training software on tablets or smartphones (Apps) offer a low-cost, widely-available solution to supplement arm physiotherapy after stroke. We assessed the proportions of hemiplegic stroke patients who, with their plegic hand, could meaningfully engage with mobile-gaming devices using a range of standard control-methods, as well as by using a novel wireless grip-controller, adapted for neurodisability. We screened all newly-diagnosed hemiplegic stroke patients presenting to a stroke centre over 6 months. Subjects were compared on their ability to control a tablet or smartphone cursor using: finger-swipe, tap, joystick, screen-tilt, and an adapted handgrip. Cursor control was graded as: no movement (0); less than full-range movement (1); full-range movement (2); directed movement (3). In total, we screened 345 patients, of which 87 satisfied recruitment criteria and completed testing. The commonest reason for exclusion was cognitive impairment. Using conventional controls, the proportion of patients able to direct cursor movement was 38-48%; and to move it full-range was 55-67% (controller comparison: p>0.1). By comparison, handgrip enabled directed control in 75%, and full-range movement in 93% (controller comparison: p<0.001). This difference between controllers was most apparent amongst severely-disabled subjects, with 0% achieving directed or full-range control with conventional controls, compared to 58% and 83% achieving these two levels of movement, respectively, with handgrip. In conclusion, hand, or arm, training Apps played on conventional mobile devices are likely to be accessible only to mildly-disabled stroke patients. Technological adaptations such as grip-control can enable more severely affected subjects to engage with self-training software.

  8. Opportunities and limitations for using new media and mobile phones to expand access to sexual and reproductive health information and services for adolescent girls and young women in six Nigerian states.

    PubMed

    Akinfaderin-Agarau, Fadekem; Chirtau, Manre; Ekponimo, Sylvia; Power, Samantha

    2012-06-01

    Reproductive health problems are a challenge affecting young people in Nigeria. Education as a Vaccine (EVA) implements the My Question and Answer Service, using mobile phones to provide sexual and reproductive health (SRH) information and services. Use of the service by adolescent girls and young women is low. Focus group discussions were held with 726 females to assess their access to mobile phones, as well as the barriers and limitations to the use of their phones to seek SRH information and services. Results demonstrate high mobile phone access but limited use of phones to access SRH information and services. Barriers to use of these services include cost of service for young female clients, request for socio-demographic information that could break anonymity, poor marketing and publicity, socio-cultural beliefs and expectations of young girls, individual personality and beliefs, as well as infrastructural/network quality. It is therefore recommended that these barriers be adequately addressed to increase the potential use of mobile phone for providing adolescent and young girls with SRH information and services. In addition, further initiatives and research are needed to explore the potentials of social media in meeting this need.

  9. Power prediction in mobile communication systems using an optimal neural-network structure.

    PubMed

    Gao, X M; Gao, X Z; Tanskanen, J A; Ovaska, S J

    1997-01-01

    Presents a novel neural-network-based predictor for received power level prediction in direct sequence code division multiple access (DS/CDMA) systems. The predictor consists of an adaptive linear element (Adaline) followed by a multilayer perceptron (MLP). An important but difficult problem in designing such a cascade predictor is to determine the complexity of the networks. We solve this problem by using the predictive minimum description length (PMDL) principle to select the optimal numbers of input and hidden nodes. This approach results in a predictor with both good noise attenuation and excellent generalization capability. The optimized neural networks are used for predictive filtering of very noisy Rayleigh fading signals with 1.8 GHz carrier frequency. Our results show that the optimal neural predictor can provide smoothed in-phase and quadrature signals with signal-to-noise ratio (SNR) gains of about 12 and 7 dB at the urban mobile speeds of 5 and 50 km/h, respectively. The corresponding power signal SNR gains are about 11 and 5 dB. Therefore, the neural predictor is well suitable for power control applications where ldquodelaylessrdquo noise attenuation and efficient reduction of fast fading are required.

  10. Multigenerational effects of whole body exposure to 2.14 GHz W-CDMA cellular phone signals on brain function in rats.

    PubMed

    Shirai, Tomoyuki; Imai, Norio; Wang, Jianqing; Takahashi, Satoru; Kawabe, Mayumi; Wake, Kanako; Kawai, Hiroki; Watanabe, So-Ichi; Furukawa, Fumio; Fujiwara, Osamu

    2014-10-01

    The present experimental study was carried out with rats to evaluate the effects of whole body exposure to 2.14 GHz band code division multiple access (W-CDMA) signals for 20 h a day, over three generations. The average specific absorption rate (SAR, in unit of W/kg) for dams was designed at three levels: high (<0.24 W/kg), low (<0.08 W/kg), and 0 (sham exposure). Pregnant mothers (4 rats/group) were exposed from gestational day (GD) 7 to weaning and then their offspring (F1 generation, 4 males and 4 females/dam, respectively) were continuously exposed until 6 weeks of age. The F1 females were mated with F1 males at 11 weeks old, and then starting from GD 7, they were exposed continuously to the electromagnetic field (EMF; one half of the F1 offspring was used for mating, that is, two of each sex per dam and 8 males and 8 females/group, except for all offspring for the functional development tests). This protocol was repeated in the same manner on pregnant F2 females and F3 pups; the latter were killed at 10 weeks of age. No abnormalities were observed in the mother rats (F0 , F1 , and F2 ) and in the offspring (F1 , F2 , and F3 ) in any biological parameters, including neurobehavioral function. Thus, it was concluded that under the experimental conditions applied, multigenerational whole body exposure to 2.14 GHz W-CDMA signals for 20 h/day did not cause any adverse effects on the F1 , F2 , and F3 offspring.

  11. A Novel Nonlinear Precoding Detection Algorithm for VBLAST in MIMO-MC-CDMA Downlink System

    NASA Astrophysics Data System (ADS)

    Fu, Hongliang; Tao, Yong

    Considering the error propagation effect and high complexity of the Vertical Bell Labs Layered Space Time (V-BLAST), a novel nonlinear ZF-THP algorithm for VBLAST in MIMO-MC-CDMA downlink system is proposed in this paper. QR decomposition is used for precoding matrix, the nonlinear Tomlinson-Harashima Precoding (THP) is used between the sub-carrier channels of MC-CDMA to eliminate interference from other signals at the transmitter, and can obtain frequency diversity gain and eliminate effectively the error propagation effect. At the receiver, zero forcing criterion is used, and the complexity of the receiver can be reduced. Simulation results show that the proposed algorithm is better than the traditional zero forcing algorithm and the linear precoding algorithm in the system BER.

  12. Optimal channel access protocol with multiple reception capacity

    NASA Astrophysics Data System (ADS)

    Chlamtac, Imrica; Farago, Andras

    1994-04-01

    A multiple access packet communication model is analyzed in which the users can receive packets on more than one common channel. For this type of system, a new channel access protocol is presented. We prove that under heavy homogeneous load the protocol guarantees the maximum achievable throughput among all possible protocols. The general model can be applied to different systems, according to various realizations of the logical channels. For example, in packet radio networks the channels can be realized by different carrier frequencies (FDMA) or by different codes (CDMA). The simplicity and optimality of the protocol make it attractive for practical applications.

  13. Average Likelihood Methods of Classification of Code Division Multiple Access (CDMA)

    DTIC Science & Technology

    2016-05-01

    where the system’s stochastic model is either incomplete or too complex to be described in mathematical terms. Feature based methods often provide an...developing mathematical rules that guarantees optimal performance in noise, i.e., rules that guarantee the lowest error in classification. The method is...suitable in problems where models are available and have low complexity. Its main disadvantage is the development of rules due to the mathematical

  14. Analysis of three-dimensional SAR distributions emitted by mobile phones in an epidemiological perspective.

    PubMed

    Deltour, Isabelle; Wiart, Joe; Taki, Masao; Wake, Kanako; Varsier, Nadège; Mann, Simon; Schüz, Joachim; Cardis, Elisabeth

    2011-12-01

    The three-dimensional distribution of the specific absorption rate of energy (SAR) in phantom models was analysed to detect clusters of mobile phones producing similar spatial deposition of energy in the head. The clusters' characteristics were described from the phones external features, frequency band and communication protocol. Compliance measurements with phones in cheek and tilt positions, and on the left and right side of a physical phantom were used. Phones used the Personal Digital Cellular (PDC), Code division multiple access One (CdmaOne), Global System for Mobile Communications (GSM) and Nordic Mobile Telephony (NMT) communication systems, in the 800, 900, 1500 and 1800 MHz bands. Each phone's measurements were summarised by the half-ellipsoid in which the SAR values were above half the maximum value. Cluster analysis used the Partitioning Around Medoids algorithm. The dissimilarity measure was based on the overlap of the ellipsoids, and the Manhattan distance was used for robustness analysis. Within the 800 MHz frequency band, and in part within the 900 MHz and the 1800 MHz frequency bands, weak clustering was obtained for the handset shape (bar phone, flip with top and flip with central antennas), but only in specific positions (tilt or cheek). On measurements of 120 phones, the three-dimensional distribution of SAR in phantom models did not appear to be related to particular external phone characteristics or measurement characteristics, which could be used for refining the assessment of exposure to radiofrequency energy within the brain in epidemiological studies such as the Interphone.

  15. Performance Analysis of a CDMA VSAT System With Convoltional and Reed-Solomon Coding

    DTIC Science & Technology

    2002-09-01

    Error Correction (FEC), Walsh codes and PN sequences are used to generate a CDMA system and FEC is used to further improve the performance. Convolutional and block coding methods are examined and the results are obtained for each different case, including concatenated use of the codes, The performance of the system is given in terms of Bit Error Rate (BER), As observed from the results, the performance is mainly affected by the number of users and the code

  16. Electromagnetic Interference Assessment of CDMA and GSM Wireless Phones to Aircraft Navigation Radios

    NASA Technical Reports Server (NTRS)

    Ely, Jay J.; Nguyen, Truong X.; Koppen, Sandra V.; Salud, M. Theresa

    2002-01-01

    To address the concern for cellular phone electromagnetic interference (EMI) to aircraft radios, a radiated emission measurement process for CDMA (IS-95) and GSM (ETSI GSM 11.22) wireless handsets was developed. Spurious radiated emissions were efficiently characterized from devices tested in either a semi-anechoic or reverberation chamber, in terms of effective isotropic radiated power. Eight representative handsets (4 GSM, 4 CDMA) were commanded to operate while varying their radio transmitter parameters (power, modulation, etc.). This report provides a detailed description of the measurement process and resulting data, which may subsequently be used by others as a basis of consistent evaluation for cellular/PCS phones, Bluetooth, IEEE802.11b, IEEE802.11a, FRS/GMRS radios, and other portable transmitters. Aircraft interference path loss (IPL) and navigation radio interference threshold data from numerous reference documents, standards, and NASA partnerships were compiled. Using this data, a preliminary risk assessment is provided for CDMA and GSM wireless phone interference to aircraft localizer, Glideslope, VOR, and GPS radio receivers on typical transport airplanes. The report identifies where existing data for device emissions, IPL, and navigation radio interference thresholds needs to be extended for an accurate risk assessment for wireless transmitters in aircraft.

  17. SMAC: A soft MAC to reduce control overhead and latency in CDMA-based AMI networks

    DOE PAGES

    Garlapati, Shravan; Kuruganti, Teja; Buehrer, Michael R.; ...

    2015-10-26

    The utilization of state-of-the-art 3G cellular CDMA technologies in a utility owned AMI network results in a large amount of control traffic relative to data traffic, increases the average packet delay and hence are not an appropriate choice for smart grid distribution applications. Like the CDG, we consider a utility owned cellular like CDMA network for smart grid distribution applications and classify the distribution smart grid data as scheduled data and random data. Also, we propose SMAC protocol, which changes its mode of operation based on the type of the data being collected to reduce the data collection latency andmore » control overhead when compared to 3G cellular CDMA2000 MAC. The reduction in the data collection latency and control overhead aids in increasing the number of smart meters served by a base station within the periodic data collection interval, which further reduces the number of base stations needed by a utility or reduces the bandwidth needed to collect data from all the smart meters. The reduction in the number of base stations and/or the reduction in the data transmission bandwidth reduces the CAPital EXpenditure (CAPEX) and OPerational EXpenditure (OPEX) of the AMI network. Finally, the proposed SMAC protocol is analyzed using markov chain, analytical expressions for average throughput and average packet delay are derived, and simulation results are also provided to verify the analysis.« less

  18. SMAC: A soft MAC to reduce control overhead and latency in CDMA-based AMI networks

    SciTech Connect

    Garlapati, Shravan; Kuruganti, Teja; Buehrer, Michael R.; Reed, Jeffrey H.

    2015-10-26

    The utilization of state-of-the-art 3G cellular CDMA technologies in a utility owned AMI network results in a large amount of control traffic relative to data traffic, increases the average packet delay and hence are not an appropriate choice for smart grid distribution applications. Like the CDG, we consider a utility owned cellular like CDMA network for smart grid distribution applications and classify the distribution smart grid data as scheduled data and random data. Also, we propose SMAC protocol, which changes its mode of operation based on the type of the data being collected to reduce the data collection latency and control overhead when compared to 3G cellular CDMA2000 MAC. The reduction in the data collection latency and control overhead aids in increasing the number of smart meters served by a base station within the periodic data collection interval, which further reduces the number of base stations needed by a utility or reduces the bandwidth needed to collect data from all the smart meters. The reduction in the number of base stations and/or the reduction in the data transmission bandwidth reduces the CAPital EXpenditure (CAPEX) and OPerational EXpenditure (OPEX) of the AMI network. Finally, the proposed SMAC protocol is analyzed using markov chain, analytical expressions for average throughput and average packet delay are derived, and simulation results are also provided to verify the analysis.

  19. Multiple Access Schemes for Lunar Missions

    NASA Technical Reports Server (NTRS)

    Deutsch, Leslie; Hamkins, Jon; Stocklin, Frank J.

    2010-01-01

    Two years ago, the NASA Coding, Modulation, and Link Protocol (CMLP) study was completed. The study, led by the authors of this paper, recommended codes, modulation schemes, and desired attributes of link protocols for all space communication links in NASA's future space architecture. Portions of the NASA CMLP team were reassembled to resolve one open issue: the use of multiple access (MA) communication from the lunar surface. The CMLP-MA team analyzed and simulated two candidate multiple access schemes that were identified in the original CMLP study: Code Division MA (CDMA) and Frequency Division MA (FDMA) based on a bandwidth-efficient Continuous Phase Modulation (CPM) with a superimposed Pseudo-Noise (PN) ranging signal (CPM/PN). This paper summarizes the results of the analysis and simulation of the CMLP-MA study and describes the final recommendations.

  20. Computationally Efficient Blind Code Synchronization for Asynchronous DS-CDMA Systems with Adaptive Antenna Arrays

    NASA Astrophysics Data System (ADS)

    Hu, Chia-Chang

    2005-12-01

    A novel space-time adaptive near-far robust code-synchronization array detector for asynchronous DS-CDMA systems is developed in this paper. There are the same basic requirements that are needed by the conventional matched filter of an asynchronous DS-CDMA system. For the real-time applicability, a computationally efficient architecture of the proposed detector is developed that is based on the concept of the multistage Wiener filter (MWF) of Goldstein and Reed. This multistage technique results in a self-synchronizing detection criterion that requires no inversion or eigendecomposition of a covariance matrix. As a consequence, this detector achieves a complexity that is only a linear function of the size of antenna array ([InlineEquation not available: see fulltext.]), the rank of the MWF ([InlineEquation not available: see fulltext.]), the system processing gain ([InlineEquation not available: see fulltext.]), and the number of samples in a chip interval ([InlineEquation not available: see fulltext.]), that is,[InlineEquation not available: see fulltext.]. The complexity of the equivalent detector based on the minimum mean-squared error (MMSE) or the subspace-based eigenstructure analysis is a function of[InlineEquation not available: see fulltext.]. Moreover, this multistage scheme provides a rapid adaptive convergence under limited observation-data support. Simulations are conducted to evaluate the performance and convergence behavior of the proposed detector with the size of the[InlineEquation not available: see fulltext.]-element antenna array, the amount of the[InlineEquation not available: see fulltext.]-sample support, and the rank of the[InlineEquation not available: see fulltext.]-stage MWF. The performance advantage of the proposed detector over other DS-CDMA detectors is investigated as well.

  1. Optical multiple access techniques for on-board routing

    NASA Technical Reports Server (NTRS)

    Mendez, Antonio J.; Park, Eugene; Gagliardi, Robert M.

    1992-01-01

    The purpose of this research contract was to design and analyze an optical multiple access system, based on Code Division Multiple Access (CDMA) techniques, for on board routing applications on a future communication satellite. The optical multiple access system was to effect the functions of a circuit switch under the control of an autonomous network controller and to serve eight (8) concurrent users at a point to point (port to port) data rate of 180 Mb/s. (At the start of this program, the bit error rate requirement (BER) was undefined, so it was treated as a design variable during the contract effort.) CDMA was selected over other multiple access techniques because it lends itself to bursty, asynchronous, concurrent communication and potentially can be implemented with off the shelf, reliable optical transceivers compatible with long term unattended operations. Temporal, temporal/spatial hybrids and single pulse per row (SPR, sometimes termed 'sonar matrices') matrix types of CDMA designs were considered. The design, analysis, and trade offs required by the statement of work selected a temporal/spatial CDMA scheme which has SPR properties as the preferred solution. This selected design can be implemented for feasibility demonstration with off the shelf components (which are identified in the bill of materials of the contract Final Report). The photonic network architecture of the selected design is based on M(8,4,4) matrix codes. The network requires eight multimode laser transmitters with laser pulses of 0.93 ns operating at 180 Mb/s and 9-13 dBm peak power, and 8 PIN diode receivers with sensitivity of -27 dBm for the 0.93 ns pulses. The wavelength is not critical, but 830 nm technology readily meets the requirements. The passive optical components of the photonic network are all multimode and off the shelf. Bit error rate (BER) computations, based on both electronic noise and intercode crosstalk, predict a raw BER of (10 exp -3) when all eight users are

  2. Electrical Spreading Code-Based OFDM Optical Access Networks for Budget Enhancement and Reduced System Bandwidth Requirement

    NASA Astrophysics Data System (ADS)

    Kumar, Pravindra; Srivastava, Anand

    2015-12-01

    Passive optical networks based on orthogonal frequency division multiplexing (OFDM-PON) give better performance in high-speed optical access networks. For further improvement in performance, a new architecture of OFDM-PON based on spreading code in electrical domain is proposed and analytically analyzed in this paper. This approach is referred as hybrid multi-carrier code division multiple access-passive optical network (MC-CDMA-PON). Analytical results show that at bit error rate (BER) of 10-3, there is 9.4 dB and 14.2 dB improvement in optical power budget for downstream and upstream, respectively, with MC-CDMA-PON system as compared to conventional OFDM-PON system for the same number of optical network units (ONUs).

  3. Comparison of two underwater acoustic communications techniques for multi-user access

    NASA Astrophysics Data System (ADS)

    Hursky, Paul; Siderius, T. Martin; Kauaiex Group

    2004-05-01

    Frequency hopped frequency shift keying (FHFSK) and code division multiple access (CDMA) are two different modulation techniques for multiple users to communicate with a single receiver simultaneously. In July 2003, these two techniques were tested alongside each other in a shallow water coastal environment off the coast of Kauai. A variety of instruments were used to measure the prevailing oceanography, enabling detailed modeling of the channel. The channel was acoustically probed using LFM waveforms and m-sequences as well. We will present the results of demodulating the FHFSK and CDMA waveforms and discuss modeling the channel for the purpose of predicting multi-user communications performance. a)Michael B. Porter, Paul Hursky, Martin Siderius (SAIC), Mohsen Badiey (UD), Jerald Caruthers (USM), William S. Hodgkiss, Kaustubha Raghukumar (SIO), Dan Rouseff, Warren Fox (APL-UW), Christian de Moustier, Brian Calder, Barbara J. Kraft (UNH), Keyko McDonald (SPAWARSSC), Peter Stein, James K. Lewis, and Subramaniam Rajan (SSI).

  4. Comparison of two underwater acoustic communications techniques for multi-user access

    NASA Astrophysics Data System (ADS)

    Hursky, Paul; Siderius, T. Martin; Kauaiex Group

    2001-05-01

    Frequency hopped frequency shift keying (FHFSK) and code division multiple access (CDMA) are two different modulation techniques for multiple users to communicate with a single receiver simultaneously. In July 2003, these two techniques were tested alongside each other in a shallow water coastal environment off the coast of Kauai. A variety of instruments were used to measure the prevailing oceanography, enabling detailed modeling of the channel. The channel was acoustically probed using LFM waveforms and m-sequences as well. We will present the results of demodulating the FHFSK and CDMA waveforms and discuss modeling the channel for the purpose of predicting multi-user communications performance. a)Michael B. Porter, Paul Hursky, Martin Siderius (SAIC), Mohsen Badiey (UD), Jerald Caruthers (USM), William S. Hodgkiss, Kaustubha Raghukumar (SIO), Dan Rouseff, Warren Fox (APL-UW), Christian de Moustier, Brian Calder, Barbara J. Kraft (UNH), Keyko McDonald (SPAWARSSC), Peter Stein, James K. Lewis, and Subramaniam Rajan (SSI).

  5. Mobile learning in medicine

    NASA Astrophysics Data System (ADS)

    Serkan Güllüoüǧlu, Sabri

    2013-03-01

    This paper outlines the main infrastructure for implicating mobile learning in medicine and present a sample mobile learning application for medical learning within the framework of mobile learning systems. Mobile technology is developing nowadays. In this case it will be useful to develop different learning environments using these innovations in internet based distance education. M-learning makes the most of being on location, providing immediate access, being connected, and acknowledges learning that occurs beyond formal learning settings, in places such as the workplace, home, and outdoors. Central to m-learning is the principle that it is the learner who is mobile rather than the device used to deliver m learning. The integration of mobile technologies into training has made learning more accessible and portable. Mobile technologies make it possible for a learner to have access to a computer and subsequently learning material and activities; at any time and in any place. Mobile devices can include: mobile phone, personal digital assistants (PDAs), personal digital media players (eg iPods, MP3 players), portable digital media players, portable digital multimedia players. Mobile learning (m-learning) is particularly important in medical education, and the major users of mobile devices are in the field of medicine. The contexts and environment in which learning occurs necessitates m-learning. Medical students are placed in hospital/clinical settings very early in training and require access to course information and to record and reflect on their experiences while on the move. As a result of this paper, this paper strives to compare and contrast mobile learning with normal learning in medicine from various perspectives and give insights and advises into the essential characteristics of both for sustaining medical education.

  6. An optical CDMA system based on chaotic sequences

    NASA Astrophysics Data System (ADS)

    Liu, Xiao-lei; En, De; Wang, Li-guo

    2014-03-01

    In this paper, a coherent asynchronous optical code division multiple access (OCDMA) system is proposed, whose encoder/decoder is an all-optical generator. This all-optical generator can generate analog and bipolar chaotic sequences satisfying the logistic maps. The formula of bit error rate (BER) is derived, and the relationship of BER and the number of simultaneous transmissions is analyzed. Due to the good property of correlation, this coherent OCDMA system based on these bipolar chaotic sequences can support a large number of simultaneous users, which shows that these chaotic sequences are suitable for asynchronous OCDMA system.

  7. A New Aloha Anti-Collision Algorithm Based on CDMA

    NASA Astrophysics Data System (ADS)

    Bai, Enjian; Feng, Zhu

    The tags' collision is a common problem in RFID (radio frequency identification) system. The problem has affected the integrity of the data transmission during the process of communication in the RFID system. Based on analysis of the existing anti-collision algorithm, a novel anti-collision algorithm is presented. The new algorithm combines the group dynamic frame slotted Aloha algorithm with code division multiple access technology. The algorithm can effectively reduce the collision probability between tags. Under the same number of tags, the algorithm is effective in reducing the reader recognition time and improve overall system throughput rate.

  8. A study of multiple access schemes in satellite control network

    NASA Astrophysics Data System (ADS)

    Mo, Zijian; Wang, Zhonghai; Xiang, Xingyu; Wang, Gang; Chen, Genshe; Nguyen, Tien; Pham, Khanh; Blasch, Erik

    2016-05-01

    Satellite Control Networks (SCN) have provided launch control for space lift vehicles; tracking, telemetry and commanding (TTC) for on-orbit satellites; and, test support for space experiments since the 1960s. Currently, SCNs encounter a new challenge: how to maintain the high reliability of services when sharing the spectrum with emerging commercial services. To achieve this goal, the capability of multiple satellites reception is deserved as an update/modernization of SCN in the future. In this paper, we conducts an investigation of multiple access techniques in SCN scenario, e.g., frequency division multiple access (FDMA) and coded division multiple access (CDMA). First, we introduce two upgrade options of SCN based on FDMA and CDMA techniques. Correspondingly, we also provide their performance analysis, especially the system improvement in spectrum efficiency and interference mitigation. Finally, to determine the optimum upgrade option, this work uses CRISP, i.e., Cost, Risk, Installation, Supportability and Performance, as the baseline approach for a comprehensive trade study of these two options. Extensive numerical and simulation results are presented to illustrate the theoretical development.

  9. SIR-based call admission control for DS-CDMA cellular systems

    NASA Astrophysics Data System (ADS)

    Liu, Zhao; Elzarki, Magda

    1994-05-01

    Signal-to-interference ratio (SIR)-based call admission control (CAC) algorithms are proposed and studied in a DS-CDMA cellular system. Residual capacity is introduced as the additional number of initial calls a base station can accept such that system-wide outage probability will be guaranteed to remain below a certain level. The residual capacity at each cell is updated dynamically according to the reverse-link SIR measurements at the base station. A 2(sup k) factorial experimental design and analysis via computer simulations is used to study the impact of the parameters used in the algorithms. The influence of these parameters on system performance, namely blocking probability and outage probability, is then examined via simulation. The performance of the algorithms is compared together with that of a fixed call admission control scheme (fixed CAC) under both homogeneous and hot spot traffic loadings. The results show that SIR-based CAC always outperforms fixed CAC even under overload situations, which is not the case in FDMA/TDMA cellular systems. The primary benefit of SIR-based CAC in DS-CDMA cellular systems, however, lies in improving the system performance under hot spot traffics.

  10. Accessing structure and dynamics of mobile phase in organic solids by real-time T1C filter PISEMA NMR spectroscopy.

    PubMed

    Zhang, Rongchun; Chen, Yuzhu; Chen, Tiehong; Sun, Pingchuan; Li, Baohui; Ding, Datong

    2012-01-26

    The structure and dynamic behavior of mobile components play a significant role in determining properties of solid materials. Herein, we propose a novel real-time spectrum-editing method to extract signals of mobile components in organic solids on the basis of the polarization inversion spin exchange at magic angle (PISEMA) pulse sequence and the difference in (13)C T(1) values of rigid and mobile components. From the dipolar splitting spectrum sliced along the heteronuclear dipolar coupling dimension of the 2D spectrum, the structural and dynamic information can be obtained, such as the distances between atoms, the dipolar coupling strength, the order parameter of the polymer backbone chain, and so on. Furthermore, our proposed method can be used to achieve the separation of overlapped NMR signals of mobile and rigid phases in the PISEMA experiment. The high efficacy of this 2D NMR method is demonstrated on organic solids, including crystalline L-alanine, semicrystalline polyamide-6, and the natural abundant silk fibroin.

  11. Mobile Phone Usage for M-Learning: Comparing Heavy and Light Mobile Phone Users

    ERIC Educational Resources Information Center

    Suki, Norbayah Mohd; Suki, Norazah Mohd

    2007-01-01

    Purpose: Mobile technologies offer the opportunity to embed learning in a natural environment. The objective of the study is to examine how the usage of mobile phones for m-learning differs between heavy and light mobile phone users. Heavy mobile phone users are hypothesized to have access to/subscribe to one type of mobile content than light…

  12. Doctors going mobile.

    PubMed

    Romano, Ron; Baum, Neil

    2014-01-01

    Having a Web page and a blog site are the minimum requirements for an Internet presence in the new millennium. However, a Web page that loads on a personal computer or a laptop will be ineffective on a mobile or cellular phone. Today, with more existing and potential patients having access to cellular technology, it is necessary to reconfigure the appearance of your Web site that appears on a mobile phone. This article discusses mobile computing and suggestions for improving the appearance of your Web site on a mobile or cellular phone.

  13. AccessAbility @ Cleveland Public Library.

    ERIC Educational Resources Information Center

    Mates, Barbara T.

    2003-01-01

    Describes several programs that were developed by staff at the Cleveland (Ohio) Public Library to be accessible to users with disabilities. Highlights include a Braille reading program; sensory garden; poetry club; book club based on talking books; wheelchair athletics; touching museum artifacts; and a mobile library for users who could not visit…

  14. Adaptive Code Division Multiple Access Protocol for Wireless Network-on-Chip Architectures

    NASA Astrophysics Data System (ADS)

    Vijayakumaran, Vineeth

    Massive levels of integration following Moore's Law ushered in a paradigm shift in the way on-chip interconnections were designed. With higher and higher number of cores on the same die traditional bus based interconnections are no longer a scalable communication infrastructure. On-chip networks were proposed enabled a scalable plug-and-play mechanism for interconnecting hundreds of cores on the same chip. Wired interconnects between the cores in a traditional Network-on-Chip (NoC) system, becomes a bottleneck with increase in the number of cores thereby increasing the latency and energy to transmit signals over them. Hence, there has been many alternative emerging interconnect technologies proposed, namely, 3D, photonic and multi-band RF interconnects. Although they provide better connectivity, higher speed and higher bandwidth compared to wired interconnects; they also face challenges with heat dissipation and manufacturing difficulties. On-chip wireless interconnects is one other alternative proposed which doesn't need physical interconnection layout as data travels over the wireless medium. They are integrated into a hybrid NOC architecture consisting of both wired and wireless links, which provides higher bandwidth, lower latency, lesser area overhead and reduced energy dissipation in communication. However, as the bandwidth of the wireless channels is limited, an efficient media access control (MAC) scheme is required to enhance the utilization of the available bandwidth. This thesis proposes using a multiple access mechanism such as Code Division Multiple Access (CDMA) to enable multiple transmitter-receiver pairs to send data over the wireless channel simultaneously. It will be shown that such a hybrid wireless NoC with an efficient CDMA based MAC protocol can significantly increase the performance of the system while lowering the energy dissipation in data transfer. In this work it is shown that the wireless NoC with the proposed CDMA based MAC protocol

  15. Accessing Inpatient Rehabilitation after Acute Severe Stroke: Age, Mobility, Prestroke Function and Hospital Unit Are Associated with Discharge to Inpatient Rehabilitation

    ERIC Educational Resources Information Center

    Hakkennes, Sharon; Hill, Keith D.; Brock, Kim; Bernhardt, Julie; Churilov, Leonid

    2012-01-01

    The objective of this study was to identify the variables associated with discharge to inpatient rehabilitation following acute severe stroke and to determine whether hospital unit contributed to access. Five acute hospitals in Victoria, Australia participated in this study. Patients were eligible for inclusion if they had suffered an acute severe…

  16. Assessing Mobile Phone Access and Perceptions for Texting-Based mHealth Interventions Among Expectant Mothers and Child Caregivers in Remote Regions of Northern Kenya: A Survey-Based Descriptive Study

    PubMed Central

    Carmichael, Jason-Louis; Hapanna, Galgallo Waqo; Wangoo, Patrick Gikaria; Karanja, Sarah; Wanyama, Denis; Muhula, Samuel Opondo; Kyomuhangi, Lennie Bazira; Loolpapit, Mores; Wangalwa, Gilbert Bwire; Kinagwi, Koki; Lester, Richard Todd

    2017-01-01

    Background With a dramatic increase in mobile phone use in low- and middle-income countries, mobile health (mHealth) has great potential to connect health care services directly to participants enrolled and improve engagement of care. Rural and remote global settings may pose both significant challenges and opportunities. Objective The objective of our study was to understand the demographics, phone usage and ownership characteristics, and feasibility among patients in rural and remote areas of Kenya of having text messaging (short messaging service, SMS)-based mHealth intervention for improvements in antenatal care attendance and routine immunization among children in Northern Kenya. Methods A survey-based descriptive study was conducted between October 2014 and February 2015 at 8 health facilities in Northern Kenya as part of a program to scale up an mHealth service in rural and remote regions. The study was conducted at 6 government health facilities in Isiolo, Marsabit, and Samburu counties in remote and northern arid lands (NAL). Two less remote health facilities in Laikipia and Meru counties in more populated central highlands were included as comparison sites. Results A total of 284 participants were surveyed; 63.4% (180/284) were from NAL clinics, whereas 36.6% (104/284) were from adjacent central highland clinics. In the NAL, almost half (48.8%, 88/180) reported no formal education and 24.4% (44/180) self-identified as nomads. The majority of participants from both regions had access to mobile phone: 99.0% (103/104) of participants from central highlands and 82.1% (147/180) of participants from NAL. Among those who had access to a phone, there were significant differences in network challenges and technology literacy between the 2 regions. However, there was no significant difference in the proportion of participants from NAL and central highlands who indicated that they would like to receive a weekly SMS text message from their health care provider (90

  17. The analysis of MAI in large scale MIMO-CDMA system

    NASA Astrophysics Data System (ADS)

    Berceanu, Madalina-Georgiana; Voicu, Carmen; Halunga, Simona

    2016-12-01

    Recently, technological development imposed a rapid growth in the use of data carried by cellular services, which also implies the necessity of higher data rates and lower latency. To meet the users' demands, it was brought into discussion a series of new data processing techniques. In this paper, we approached the MIMO technology that uses multiple antennas at the receiver and transmitter ends. To study the performances obtained by this technology, we proposed a MIMO-CDMA system, where image transmission has been used instead of random data transmission to take benefit of a larger range of quality indicators. In the simulations we increased the number of antennas, we observed how the performances of the system are modified and, based on that, we were able to make a comparison between a conventional MIMO and a Large Scale MIMO system, in terms of BER and MSSIM index, which is a metric that compares the quality of the image before transmission with the received one.

  18. A Study on Railway Signal System to Apply CDMA-QAM Method

    NASA Astrophysics Data System (ADS)

    Mochizuki, Hiroshi; Asano, Akira; Sano, Minoru; Takahashi, Sei; Nakamura, Hideo

    Recently, QAM (Quadrature Amplitude Modulation) transmission is paid to attention in digital modulation method, and it has been used for wireless LAN and digital broadcasting. QAM is a modulation method that puts information on carrier amplitude and phase. So QAM can achieve high-capacity data transmission that the use efficiency of frequency band is good. But QAM has a bad characteristic that is weak to the noise and the interference because distance between each symbol is short. Then we propose the method that not transmission data but CDMA signal, obtained after transmission data is modulated by spread code and multiplexed, is given to each symbol of QAM. And we studied about railway signal system on track circuit as a sample to apply this method. As result of computer simulations, we verified to be able to achieve the improvement of signal to noise ratio by optimizing the constellation map of QAM. We report with the method of a synchronous acquisition.

  19. Replica Analysis of Multiuser Detection for Code Division Multiple Access with M-Ary Phase-Shift Keying

    NASA Astrophysics Data System (ADS)

    Kato, Hiroyuki; Okada, Masato; Miyoshi, Seiji

    2013-07-01

    We analyze the performance of the maximizer of the posterior marginals (MPM) detector for code division multiple access (CDMA) multiuser detection with M-ary phase shift keying (M-ary PSK) in the large system limit by the replica method. The obtained theory agrees with computer simulation reasonably well. We also derive the theory in the case of the large M limit and discuss the dependence of the properties of M-ary PSK CDMA communication on M. We show that the waterfall phenomenon occurs for both the finite and infinite values of M. We also show that a value of M for which the decoded phase information on the original user symbol becomes minimum exists. Furthermore, we discuss the relationship between the theory based on the replica method and that based on self-consistent signal-to-noise analysis (SCSNA).

  20. Mobile medical image retrieval

    NASA Astrophysics Data System (ADS)

    Duc, Samuel; Depeursinge, Adrien; Eggel, Ivan; Müller, Henning

    2011-03-01

    Images are an integral part of medical practice for diagnosis, treatment planning and teaching. Image retrieval has gained in importance mainly as a research domain over the past 20 years. Both textual and visual retrieval of images are essential. In the process of mobile devices becoming reliable and having a functionality equaling that of formerly desktop clients, mobile computing has gained ground and many applications have been explored. This creates a new field of mobile information search & access and in this context images can play an important role as they often allow understanding complex scenarios much quicker and easier than free text. Mobile information retrieval in general has skyrocketed over the past year with many new applications and tools being developed and all sorts of interfaces being adapted to mobile clients. This article describes constraints of an information retrieval system including visual and textual information retrieval from the medical literature of BioMedCentral and of the RSNA journals Radiology and Radiographics. Solutions for mobile data access with an example on an iPhone in a web-based environment are presented as iPhones are frequently used and the operating system is bound to become the most frequent smartphone operating system in 2011. A web-based scenario was chosen to allow for a use by other smart phone platforms such as Android as well. Constraints of small screens and navigation with touch screens are taken into account in the development of the application. A hybrid choice had to be taken to allow for taking pictures with the cell phone camera and upload them for visual similarity search as most producers of smart phones block this functionality to web applications. Mobile information access and in particular access to images can be surprisingly efficient and effective on smaller screens. Images can be read on screen much faster and relevance of documents can be identified quickly through the use of images contained in

  1. 47 CFR 25.254 - Special requirements for ancillary terrestrial components operating in the 1610-1626.5 MHz/2483.5...

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... Considerations for the Coordination Between Mobile Satellite Service (MSS) Networks Utilizing Code Division Multiple Access (CDMA) and Other Spread Spectrum Techniques in the 1-3 GHz Band” (1995). Recommendation...

  2. 47 CFR 25.254 - Special requirements for ancillary terrestrial components operating in the 1610-1626.5 MHz/2483.5...

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... Considerations for the Coordination Between Mobile Satellite Service (MSS) Networks Utilizing Code Division Multiple Access (CDMA) and Other Spread Spectrum Techniques in the 1-3 GHz Band” (1995). Recommendation...

  3. Acceptability of a Mobile Smartphone Application Intervention to Improve Access to HIV Prevention and Care Services for Black Men Who Have Sex with Men in the District of Columbia.

    PubMed

    Levy, Matthew E; Watson, Christopher Chauncey; Wilton, Leo; Criss, Vittoria; Kuo, Irene; Glick, Sara Nelson; Brewer, Russell A; Magnus, Manya

    Eliminating racial HIV disparities among men who have sex with men (MSM) will require a greater uptake of HIV prevention and care interventions among Black MSM (BMSM), yet such strategies generally require meaningful engagement in a health care system that often does not meet the unique needs of BMSM. This study assessed the acceptability of, and correlates of having favorable perceptions of, a mobile smartphone application (app) intervention for BMSM that aims to remove structural barriers and improve access to culturally relevant HIV prevention and care services. An Internet-based sample of 93 BMSM completed an online survey on their perceptions of the app using 14 items measured on a 100-point visual analogue scale that were validated in exploratory factor analysis (alpha=0.95). Among the sample, perceptions of two sample app modules were generally favorable and most BMSM agreed that they would use the modules (81.2% and 87.1%). Correlates of having favorable perceptions included trusting medical advice from social networks, lacking private health insurance, and not having accessed a primary care physician in the last year. Our findings warrant the further development of this app and point to subgroups of BMSM for which it may have the greatest impact.

  4. Acceptability of a Mobile Smartphone Application Intervention to Improve Access to HIV Prevention and Care Services for Black Men Who Have Sex with Men in the District of Columbia

    PubMed Central

    Levy, Matthew E.; Watson, Christopher Chauncey; Wilton, Leo; Criss, Vittoria; Kuo, Irene; Glick, Sara Nelson; Brewer, Russell A.; Magnus, Manya

    2015-01-01

    Eliminating racial HIV disparities among men who have sex with men (MSM) will require a greater uptake of HIV prevention and care interventions among Black MSM (BMSM), yet such strategies generally require meaningful engagement in a health care system that often does not meet the unique needs of BMSM. This study assessed the acceptability of, and correlates of having favorable perceptions of, a mobile smartphone application (app) intervention for BMSM that aims to remove structural barriers and improve access to culturally relevant HIV prevention and care services. An Internet-based sample of 93 BMSM completed an online survey on their perceptions of the app using 14 items measured on a 100-point visual analogue scale that were validated in exploratory factor analysis (alpha=0.95). Among the sample, perceptions of two sample app modules were generally favorable and most BMSM agreed that they would use the modules (81.2% and 87.1%). Correlates of having favorable perceptions included trusting medical advice from social networks, lacking private health insurance, and not having accessed a primary care physician in the last year. Our findings warrant the further development of this app and point to subgroups of BMSM for which it may have the greatest impact. PMID:26594251

  5. The mobile LBS positioning solution based on NRTK and Windows Mobile

    NASA Astrophysics Data System (ADS)

    Liao, Zhongping; Duan, Xuwen; Lu, Jingxin; Yue, Xiaoyong; Liu, Wen; He, Qianqian

    2009-12-01

    In order to meet the requirements of Location-based Service (LBS), there are many proposed positioning solutions that may be able to provide LBS support, such as GPS, Mobile Phone Location, RFID, and so on. With the most widely recognized system being the Global Positioning System (GPS) and Windows Mobile 5.0 system characteristics, this paper first provides three kinds method, i.e. invoking Win32 API, using Ports namespace and calling GPS Intermediate Driver, to receive GPS raw data on Windows Mobile devices. Since internet-based GPS VRS RTK workstation can provide real-time streaming of differential GPS corrections. The following text introduces a high precision Net-based RTK (NRTK) mobile positioning solution which is mainly equipped with a Windows Mobile 5.0 device and an Ashtech Z-Xtreme receiver. With it a rover-side (NtripClient) firstly connects to an NtripCaster which is a part of a VRS workstation, via GPRS /CDMA, using the IP and specified listening Port of the Tongji VRS workstation. Then the rover-side transmits NMEA GGA strings after the HTTP request to the NtripCaster. With that the Windows Mobile device continuously receives RTCM data back from the NtripCaster and instantly sends them out into the Ashtech Z-Xtreme receiver. Finally, the Ashtech Z-Xtreme receiver will work out vector solution information of the rover-side. Thus, this paper provides a multimode mobile LBS positioning solution based on NRTK and Windows Mobile 5.0.

  6. Increasing accessibility to the blind of virtual environments, using a virtual mobility aid based on the "EyeCane": feasibility study.

    PubMed

    Maidenbaum, Shachar; Levy-Tzedek, Shelly; Chebat, Daniel-Robert; Amedi, Amir

    2013-01-01

    Virtual worlds and environments are becoming an increasingly central part of our lives, yet they are still far from accessible to the blind. This is especially unfortunate as such environments hold great potential for them for uses such as social interaction, online education and especially for use with familiarizing the visually impaired user with a real environment virtually from the comfort and safety of his own home before visiting it in the real world. We have implemented a simple algorithm to improve this situation using single-point depth information, enabling the blind to use a virtual cane, modeled on the "EyeCane" electronic travel aid, within any virtual environment with minimal pre-processing. Use of the Virtual-EyeCane, enables this experience to potentially be later used in real world environments with identical stimuli to those from the virtual environment. We show the fast-learned practical use of this algorithm for navigation in simple environments.

  7. Distributed magnetic field positioning system using code division multiple access

    NASA Technical Reports Server (NTRS)

    Prigge, Eric A. (Inventor)

    2003-01-01

    An apparatus and methods for a magnetic field positioning system use a fundamentally different, and advantageous, signal structure and multiple access method, known as Code Division Multiple Access (CDMA). This signal architecture, when combined with processing methods, leads to advantages over the existing technologies, especially when applied to a system with a large number of magnetic field generators (beacons). Beacons at known positions generate coded magnetic fields, and a magnetic sensor measures a sum field and decomposes it into component fields to determine the sensor position and orientation. The apparatus and methods can have a large `building-sized` coverage area. The system allows for numerous beacons to be distributed throughout an area at a number of different locations. A method to estimate position and attitude, with no prior knowledge, uses dipole fields produced by these beacons in different locations.

  8. College Access Marketing

    ERIC Educational Resources Information Center

    Tremblay, Christopher W.

    2011-01-01

    College Access Marketing (CAM) is a relatively new phenomenon that seeks to positively influence the college-going rate. This report defines CAM, describes CAM examples, and discusses how CAM seeks to counter barriers to college. It explores four main elements of CAM: information, marketing, advocacy, and social mobilization. Further, it…

  9. Efficient Mobility Management Signalling in Network Mobility Supported PMIPV6.

    PubMed

    Samuelraj, Ananthi Jebaseeli; Jayapal, Sundararajan

    2015-01-01

    Proxy Mobile IPV6 (PMIPV6) is a network based mobility management protocol which supports node's mobility without the contribution from the respective mobile node. PMIPV6 is initially designed to support individual node mobility and it should be enhanced to support mobile network movement. NEMO-BSP is an existing protocol to support network mobility (NEMO) in PMIPV6 network. Due to the underlying differences in basic protocols, NEMO-BSP cannot be directly applied to PMIPV6 network. Mobility management signaling and data structures used for individual node's mobility should be modified to support group nodes' mobility management efficiently. Though a lot of research work is in progress to implement mobile network movement in PMIPV6, it is not yet standardized and each suffers with different shortcomings. This research work proposes modifications in NEMO-BSP and PMIPV6 to achieve NEMO support in PMIPV6. It mainly concentrates on optimizing the number and size of mobility signaling exchanged while mobile network or mobile network node changes its access point.

  10. Efficient Mobility Management Signalling in Network Mobility Supported PMIPV6

    PubMed Central

    Jebaseeli Samuelraj, Ananthi; Jayapal, Sundararajan

    2015-01-01

    Proxy Mobile IPV6 (PMIPV6) is a network based mobility management protocol which supports node's mobility without the contribution from the respective mobile node. PMIPV6 is initially designed to support individual node mobility and it should be enhanced to support mobile network movement. NEMO-BSP is an existing protocol to support network mobility (NEMO) in PMIPV6 network. Due to the underlying differences in basic protocols, NEMO-BSP cannot be directly applied to PMIPV6 network. Mobility management signaling and data structures used for individual node's mobility should be modified to support group nodes' mobility management efficiently. Though a lot of research work is in progress to implement mobile network movement in PMIPV6, it is not yet standardized and each suffers with different shortcomings. This research work proposes modifications in NEMO-BSP and PMIPV6 to achieve NEMO support in PMIPV6. It mainly concentrates on optimizing the number and size of mobility signaling exchanged while mobile network or mobile network node changes its access point. PMID:26366431

  11. Biochemical Aspects of a Serine Protease from Caesalpinia echinata Lam. (Brazilwood) Seeds: A Potential Tool to Access the Mobilization of Seed Storage Proteins

    PubMed Central

    Praxedes-Garcia, Priscila; Cruz-Silva, Ilana; Gozzo, Andrezza Justino; Abreu Nunes, Viviane; Torquato, Ricardo José; Tanaka, Aparecida Sadae; Figueiredo-Ribeiro, Rita de Cássia; Gonzalez, Yamile Gonzalez; Araújo, Mariana da Silva

    2012-01-01

    Several proteins have been isolated from seeds of leguminous, but this is the first report that a protease was obtained from seeds of Caesalpinia echinata Lam., a tree belonging to the Fabaceae family. This enzyme was purified to homogeneity by hydrophobic interaction and anion exchange chromatographies and gel filtration. This 61-kDa serine protease (CeSP) hydrolyses H-D-prolyl-L-phenylalanyl-L-arginine-p-nitroanilide (Km 55.7 μM) in an optimum pH of 7.1, and this activity is effectively retained until 50°C. CeSP remained stable in the presence of kosmotropic anions (PO4 3−, SO4 2−, and CH3COO−) or chaotropic cations (K+ and Na+). It is strongly inhibited by TLCK, a serine protease inhibitor, but not by E-64, EDTA or pepstatin A. The characteristics of the purified enzyme allowed us to classify it as a serine protease. The role of CeSP in the seeds cannot be assigned yet but is possible to infer that it is involved in the mobilization of seed storage proteins. PMID:22629147

  12. Promoting Function, Independence, and Mobility

    MedlinePlus

    ... symptom management, the use of mobility aids, automobile adaptations and the use of assistance animals. Increasing Accessibility often requires the adaptation of tools and devices at one’s home or ...

  13. Mobile Learning Using Mobile Phones

    ERIC Educational Resources Information Center

    Vicente, Paula

    2013-01-01

    The participation in mobile learning programs is conditioned by having/using mobile communication technology. Those who do not have or use such technology cannot participate in mobile learning programs. This study evaluates who are the most likely participants of mobile learning programs by examining the demographic profile and mobile phone usage…

  14. OPACs and the Mobile Revolution

    ERIC Educational Resources Information Center

    Liston, Samuel

    2009-01-01

    Since the turn of the century, one of the hottest topics in the IT world has been the coming mobile revolution. While there's been some arguing over the details, the fundamental tenet of the mobile revolution is that lots and lots of people will start accessing web content from handheld portable devices instead of using a traditional laptop or…

  15. An Efficient Circulant MIMO Equalizer for CDMA Downlink: Algorithm and VLSI Architecture

    NASA Astrophysics Data System (ADS)

    Guo, Yuanbin; Zhang, Jianzhong(Charlie); McCain, Dennis; Cavallaro, Joseph R.

    2006-12-01

    We present an efficient circulant approximation-based MIMO equalizer architecture for the CDMA downlink. This reduces the direct matrix inverse (DMI) of size[InlineEquation not available: see fulltext.] with[InlineEquation not available: see fulltext.] complexity to some FFT operations with[InlineEquation not available: see fulltext.] complexity and the inverse of some[InlineEquation not available: see fulltext.] submatrices. We then propose parallel and pipelined VLSI architectures with Hermitian optimization and reduced-state FFT for further complexity optimization. Generic VLSI architectures are derived for the[InlineEquation not available: see fulltext.] high-order receiver from partitioned[InlineEquation not available: see fulltext.] submatrices. This leads to more parallel VLSI design with[InlineEquation not available: see fulltext.] further complexity reduction. Comparative study with both the conjugate-gradient and DMI algorithms shows very promising performance/complexity tradeoff. VLSI design space in terms of area/time efficiency is explored extensively for layered parallelism and pipelining with a Catapult C high-level-synthesis methodology.

  16. Development of the Average Likelihood Function for Code Division Multiple Access (CDMA) Using BPSK and QPSK Symbols

    DTIC Science & Technology

    2015-01-01

    characterization of signals in terms of the modulation parameters is a field of interest relevant to military and software defined radio . Early modulation...classification algorithms were based on ad-hoc methods. These methods were applied for classifying analog signals such as AM and FM . The methods

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

    NASA Technical Reports Server (NTRS)

    Wallett, Thomas M.

    2009-01-01

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

  18. High security chaotic multiple access scheme for visible light communication systems with advanced encryption standard interleaving

    NASA Astrophysics Data System (ADS)

    Qiu, Junchao; Zhang, Lin; Li, Diyang; Liu, Xingcheng

    2016-06-01

    Chaotic sequences can be applied to realize multiple user access and improve the system security for a visible light communication (VLC) system. However, since the map patterns of chaotic sequences are usually well known, eavesdroppers can possibly derive the key parameters of chaotic sequences and subsequently retrieve the information. We design an advanced encryption standard (AES) interleaving aided multiple user access scheme to enhance the security of a chaotic code division multiple access-based visible light communication (C-CDMA-VLC) system. We propose to spread the information with chaotic sequences, and then the spread information is interleaved by an AES algorithm and transmitted over VLC channels. Since the computation complexity of performing inverse operations to deinterleave the information is high, the eavesdroppers in a high speed VLC system cannot retrieve the information in real time; thus, the system security will be enhanced. Moreover, we build a mathematical model for the AES-aided VLC system and derive the theoretical information leakage to analyze the system security. The simulations are performed over VLC channels, and the results demonstrate the effectiveness and high security of our presented AES interleaving aided chaotic CDMA-VLC system.

  19. The effect of 835.62 MHz FDMA or 847.74 MHz CDMA modulated radiofrequency radiation on the induction of micronuclei in C3H 10T(1/2) cells.

    PubMed

    Bisht, Kheem S; Moros, Eduardo G; Straube, William L; Baty, Jack D; Roti Roti, Joseph L

    2002-05-01

    To determine if radiofrequency (RF) radiation induces the formation of micronuclei, C3H 10T(1/2) cells were exposed to 835.62 MHz frequency division multiple access (FDMA) or 847.74 MHz code division multiple access (CDMA) modulated RF radiation. After the exposure to RF radiation, the micronucleus assay was performed by the cytokinesis block method using cytochalasin B treatment. The micronuclei appearing after mitosis were scored in binucleated cells using acridine orange staining. The frequency of micronuclei was scored both as the percentage of binucleated cells with micronuclei and as the number of micronuclei per 100 binucleated cells. Treatment of cells with cytochalasin B at a concentration of 2 microg/ml for 22 h was found to yield the maximum number of binucleated cells in C3H 10T(1/2) cells. The method used for the micronucleus assay in the present study detected a highly significant dose response for both indices of micronucleus production in the dose range of 0.1-1.2 Gy and it was sensitive enough to detect a significant (P > 0.05) increase in micronuclei after doses of 0.3 Gy in exponentially growing cells and after 0.9 Gy in plateau-phase cells. Exponentially growing cells or plateau-phase cells were exposed to CDMA (3.2 or 4.8 W/kg) or FDMA (3.2 or 5.1 W/kg) RF radiation for 3, 8, 16 or 24 h. In three repeat experiments, no exposure condition was found by analysis of variance to result in a significant increase relative to sham-exposed cells either in the percentage of binucleated cells with micronuclei or in the number of micronuclei per 100 binucleated cells. In this study, data from cells exposed to different RF signals at two SARs were compared to a common sham-exposed sample. We used the Dunnett's test, which is specifically designed for this purpose, and found no significant exposure-related differences for either plateau-phase cells or exponentially growing cells. Thus the results of this study are not consistent with the possibility that

  20. 78 FR 30226 - Accessibility Requirements for Internet Browsers

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-05-22

    ... into mobile phones to be accessible to individuals who are blind or visually impaired. In this document... emerging and innovative advanced communications technologies. Section 718 of the Act requires mobile phone... mobile phones to ensure that the functions of the included browser are accessible to and usable...

  1. Realizing the Promises of Mobile Learning

    ERIC Educational Resources Information Center

    Wagner, Ellen D.

    2008-01-01

    This article considers the current status of mobile learning and discusses a number of trends that are driving toward enterprise mobility, a state of technological readiness where users have full access to resources regardless of physical location. Enterprise mobility is discussed as one of several key considerations at the core of a successful…

  2. Mobile technology: streamlining practice and improving care.

    PubMed

    Blake, Holly

    2013-09-01

    The use of mobile phones in care delivery has the potential to improve the way in which care is delivered. When implemented effectively, mobile technologies can empower patients and enhance communication between patients and their health-care providers. When barriers are recognised and addressed, mobile technologies can change working lives, facilitating rapid access to information and supporting efficiency in practice.

  3. Mobile Multi-System Overview

    NASA Technical Reports Server (NTRS)

    Witoff, Robert J.; Doody, David F.

    2012-01-01

    At the time of this reporting, there are 2,589 rich mobile devices used at JPL, including 1,550 iPhones and 968 Blackberrys. Considering a total JPL population of 5,961 employees, mobile applications have a total addressable market of 43 percent of the employees at JPL, and that number is rising. While it was found that no existing desktop tools can realistically be replaced by a mobile application, there is certainly a need to improve access to these desktop tools. When an alarm occurs and an engineer is away from his desk, a convenient means of accessing relevant data can save an engineer a great deal of time and improve his job efficiency. To identify which data is relevant, an engineer benefits from a succinct overview of the data housed in 13+ tools. This need can be well met by a single, rich, mobile application that provides access to desired data across tools in the ops infrastructure.

  4. Ensuring seamlessness in mobility services

    NASA Astrophysics Data System (ADS)

    Hotti, Timo; Tavi, Jari

    2001-10-01

    The infrastructure required for wireless and mobility services is becoming increasingly complex involving a multitude of different nodes such as smart terminals, base stations, access gateways and application servers and up to tens of millions of concurrent users. For true mobility services, the need to provide seamless access to data - independent of location or device - becomes apparent. But how do you ensure that this data and the corresponding mobile applications are distributed to those network nodes where the data is needed? Whether it's managing subscriber provisioning data of a large farm of access gateways, replicating application servers to allow for system scalability or distributing application software to smart terminals, seamlessness in mobility services requires a distributed data management functionality coupled with advanced multi-user, multi-device synchronization.

  5. Arteriovenous Access

    PubMed Central

    MacRae, Jennifer M.; Dipchand, Christine; Oliver, Matthew; Moist, Louise; Yilmaz, Serdar; Lok, Charmaine; Leung, Kelvin; Clark, Edward; Hiremath, Swapnil; Kappel, Joanne; Kiaii, Mercedeh; Luscombe, Rick; Miller, Lisa M.

    2016-01-01

    Complications of vascular access lead to morbidity and may reduce quality of life. In this module, we review both infectious and noninfectious arteriovenous access complications including neuropathy, aneurysm, and high-output access. For the challenging patients who have developed many complications and are now nearing their last vascular access, we highlight some potentially novel approaches. PMID:28270919

  6. 44% efficiency operation of power heterojunction FET at near pinch-off for 3.5 V wide-band CDMA cellular phones

    NASA Astrophysics Data System (ADS)

    Nishimura, T. B.; Iwata, N.; Bito, Y.; Hau, G.

    1999-08-01

    This paper describes 1.95 GHz power performance of a double-doped AlGaAs/InGaAs/AlGaAs heterojunction FET (HJFET) operated at 3.5 V drain bias voltage for Wide-band CDMA (W-CDMA) cellular phone systems. An HJFET with a novel multilayer cap and a narrow recess structure showed a low on-resistance ( Ron) of 1.4 ohm mm. With an optimum output impedance matching at a reduced quiescent drain current of 80 mA (less than 1% of the maximum drain current), the HJFET exhibited a high power added efficiency (PAE) of 44.2% with an output power of 600 mW (28.0 dBm) and an adjacent channel leakage power ratio (ACPR) of -43 dBc at 5 MHz off-center frequency. This high PAE obtained was ascribed to an ACPR dip behavior with respect to the input power at around the W-CDMA criteria. Through an ACPR simulation with measured AM-AM and AM-PM conversion characteristics, the AM-AM conversion characteristic was found to dominate the W-CDMA ACPR rather than the AM-PM conversion.

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

    ERIC Educational Resources Information Center

    Romich, Barry A.; Vagnini, Carol B.

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

  8. Mobility and HIV.

    PubMed

    1999-01-01

    Migrants, refugees, and internally displaced people are vulnerable to HIV because they live in poor areas with little privacy, have different sexual relationships, and lack information about sexual health and services. In response to these problems, HIV prevention and care programs were initiated. The programs include: 1) involving migrant workers as both interviewers and outreach workers to better understand the idea of the migrants per Coordination of Action Research on Mobility and AIDS; 2) improving living conditions; 3) access of migrants to information and services; 4) improving the rights of the people; 5) increasing income; and 6) access to sexual health information that concerns exposure of HIV through different sexual partners.

  9. An Exposition of Current Mobile Learning Design Guidelines and Frameworks

    ERIC Educational Resources Information Center

    Teall, Ed; Wang, Minjuan; Callaghan, Vic; Ng, Jason W. P.

    2014-01-01

    As mobile devices with wireless access become more readily available, learning delivered via mobile devices of all types must be designed to ensure successful learning. This paper first examines three questions related to the design of mobile learning: 1) what mobile learning (m-learning) guidelines can be identified in the current literature, 2)…

  10. User Experience of Mobile Interactivity: How Do Mobile Websites Affect Attitudes and Relational Outcomes?

    ERIC Educational Resources Information Center

    Dou, Xue

    2013-01-01

    Mobile media offer new opportunities for fostering communications between individuals and companies. Corporate websites are being increasingly accessed via smart phones and companies are scrambling to offer a mobile-friendly user experience on their sites. However, very little is known about how interactivity in the mobile context affects user…

  11. Survey of RF exposure levels from mobile telephone base stations in Australia.

    PubMed

    Henderson, S I; Bangay, M J

    2006-01-01

    This paper reports the results of an exposure level survey of radiofrequency electromagnetic energy originating from mobile telephone base station antennas. Measurements of CDMA800, GSM900, GSM1800, and 3G(UMTS) signals were performed at distances ranging over 50 to 500 m from 60 base stations in five Australian cities. The exposure levels from these mobile telecommunications base stations were found to be well below the general public exposure limits of the ICNIRP guidelines and the Australian radiofrequency standard (ARPANSA RPS3). The highest recorded level from a single base station was 7.8 x 10(-3) W/m(2), which translates to 0.2% of the general public exposure limit.

  12. Web Accessibility and Accessibility Instruction

    ERIC Educational Resources Information Center

    Green, Ravonne A.; Huprich, Julia

    2009-01-01

    Section 508 of the Americans with Disabilities Act (ADA) mandates that programs and services be accessible to people with disabilities. While schools of library and information science (SLIS*) and university libraries should model accessible Web sites, this may not be the case. This article examines previous studies about the Web accessibility of…

  13. Advanced Mobility Handover for Mobile IPv6 Based Wireless Networks

    PubMed Central

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

    2014-01-01

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

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

    PubMed

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

    2014-01-01

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

  15. Coded access optical sensor (CAOS) imager and applications

    NASA Astrophysics Data System (ADS)

    Riza, Nabeel A.

    2016-04-01

    Starting in 2001, we proposed and extensively demonstrated (using a DMD: Digital Micromirror Device) an agile pixel Spatial Light Modulator (SLM)-based optical imager based on single pixel photo-detection (also called a single pixel camera) that is suited for operations with both coherent and incoherent light across broad spectral bands. This imager design operates with the agile pixels programmed in a limited SNR operations starring time-multiplexed mode where acquisition of image irradiance (i.e., intensity) data is done one agile pixel at a time across the SLM plane where the incident image radiation is present. Motivated by modern day advances in RF wireless, optical wired communications and electronic signal processing technologies and using our prior-art SLM-based optical imager design, described using a surprisingly simple approach is a new imager design called Coded Access Optical Sensor (CAOS) that has the ability to alleviate some of the key prior imager fundamental limitations. The agile pixel in the CAOS imager can operate in different time-frequency coding modes like Frequency Division Multiple Access (FDMA), Code-Division Multiple Access (CDMA), and Time Division Multiple Access (TDMA). Data from a first CAOS camera demonstration is described along with novel designs of CAOS-based optical instruments for various applications.

  16. Unveiling the Mobile Learning Paradox.

    PubMed

    Mather, Carey; Cummings, Elizabeth

    2015-01-01

    A mobile learning paradox exists in Australian healthcare settings. Although it is increasingly acknowledged that timely, easy, and convenient access to health information using mobile learning technologies can enhance care and improve patient outcomes, currently there is an inability for nurses to access information at the point of care. Rapid growth in the use of mobile technology has created challenges for learning and teaching in the workplace. Easy access to educational resources via mobile devices challenges traditional strategies of knowledge and skill acquisition. Redesign of learning and teaching in the undergraduate curriculum and the development of policies to support the use of mobile learning at point of care is overdue. This study explored mobile learning opportunities used by clinical supervisors in tertiary and community-based facilities in two Australian States. Individual, organisation and systems level governance were sub-themes of professionalism that emerged as the main theme and impacts on learning and teaching in situ in healthcare environments. It is imperative healthcare work redesign includes learning and teaching that supports professional identity formation of students during work integrated learning.

  17. Design of a search and rescue terminal based on the dual-mode satellite and CDMA network

    NASA Astrophysics Data System (ADS)

    Zhao, Junping; Zhang, Xuan; Zheng, Bing; Zhou, Yubin; Song, Hao; Song, Wei; Zhang, Meikui; Liu, Tongze; Zhou, Li

    2010-12-01

    The current goal is to create a set of portable terminals with GPS/BD2 dual-mode satellite positioning, vital signs monitoring and wireless transmission functions. The terminal depends on an ARM processor to collect and combine data related to vital signs and GPS/BD2 location information, and sends the message to headquarters through the military CDMA network. It integrates multiple functions as a whole. The satellite positioning and wireless transmission capabilities are integrated into the motherboard, and the vital signs sensors used in the form of belts communicate with the board through Bluetooth. It can be adjusted according to the headquarters' instructions. This kind of device is of great practical significance for operations during disaster relief, search and rescue of the wounded in wartime, non-war military operations and other special circumstances.

  18. Measured radiofrequency exposure during various mobile-phone use scenarios.

    PubMed

    Kelsh, Michael A; Shum, Mona; Sheppard, Asher R; McNeely, Mark; Kuster, Niels; Lau, Edmund; Weidling, Ryan; Fordyce, Tiffani; Kühn, Sven; Sulser, Christof

    2011-01-01

    Epidemiologic studies of mobile phone users have relied on self reporting or billing records to assess exposure. Herein, we report quantitative measurements of mobile-phone power output as a function of phone technology, environmental terrain, and handset design. Radiofrequency (RF) output data were collected using software-modified phones that recorded power control settings, coupled with a mobile system that recorded and analyzed RF fields measured in a phantom head placed in a vehicle. Data collected from three distinct routes (urban, suburban, and rural) were summarized as averages of peak levels and overall averages of RF power output, and were analyzed using analysis of variance methods. Technology was the strongest predictor of RF power output. The older analog technology produced the highest RF levels, whereas CDMA had the lowest, with GSM and TDMA showing similar intermediate levels. We observed generally higher RF power output in rural areas. There was good correlation between average power control settings in the software-modified phones and power measurements in the phantoms. Our findings suggest that phone technology, and to a lesser extent, degree of urbanization, are the two stronger influences on RF power output. Software-modified phones should be useful for improving epidemiologic exposure assessment.

  19. FQPSK techniques for satellite and mobile radio communications systems

    NASA Astrophysics Data System (ADS)

    Li, Yazhuo; Tang, Jing; Tao, Xiaofeng

    2005-11-01

    A continuous phase modulation (CPM) and constant envelope modulation (CEM) alternative of Feher-Patented quadrature phase-shift keying (FQPSK) modulation technique is presented. It is found to provide good spectral efficiencies, power efficiencies, and bit error rate (BER) performance. The modulation schemes of FQPSK are described. The spectral efficiencies, BER performance are also compared with FQPSK and other modulation techniques which are widely used in current mobile and cordless radio standards. The results show that FQPSK modulated signal exhibits much less spectrum spreading than QPSK, OQPSK, and MSK, and the error probability performance of the FQPSK is superior to those in narrow-band nonlinear channels. Based on that, the system capacity and power dissipation are also analyzed for communication systems. It is found that the encoder or receiver for the FQPSK signal to be fully compatible with original I/Q modulated one. FQPSK technique is suitable for nonlinear channels, such as satellite and mobile communications systems reducing the AM/AM and AM/PM adverse effects. At last it is also attempted to extend the application in 3G (CDMA) and 4G (OFDM) mobile communications systems.

  20. A Review on Spectral Amplitude Coding Optical Code Division Multiple Access

    NASA Astrophysics Data System (ADS)

    Kaur, Navpreet; Goyal, Rakesh; Rani, Monika

    2017-03-01

    This manuscript deals with analysis of Spectral Amplitude Coding Optical Code Division Multiple Access (SACOCDMA) system. The major noise source in optical CDMA is co-channel interference from other users known as multiple access interference (MAI). The system performance in terms of bit error rate (BER) degrades as a result of increased MAI. It is perceived that number of users and type of codes used for optical system directly decide the performance of system. MAI can be restricted by efficient designing of optical codes and implementing them with unique architecture to accommodate more number of users. Hence, it is a necessity to design a technique like spectral direct detection (SDD) technique with modified double weight code, which can provide better cardinality and good correlation property.

  1. Mobility management techniques for the next-generation wireless networks

    NASA Astrophysics Data System (ADS)

    Sun, Junzhao; Howie, Douglas P.; Sauvola, Jaakko J.

    2001-10-01

    The tremendous demands from social market are pushing the booming development of mobile communications faster than ever before, leading to plenty of new advanced techniques emerging. With the converging of mobile and wireless communications with Internet services, the boundary between mobile personal telecommunications and wireless computer networks is disappearing. Wireless networks of the next generation need the support of all the advances on new architectures, standards, and protocols. Mobility management is an important issue in the area of mobile communications, which can be best solved at the network layer. One of the key features of the next generation wireless networks is all-IP infrastructure. This paper discusses the mobility management schemes for the next generation mobile networks through extending IP's functions with mobility support. A global hierarchical framework model for the mobility management of wireless networks is presented, in which the mobility management is divided into two complementary tasks: macro mobility and micro mobility. As the macro mobility solution, a basic principle of Mobile IP is introduced, together with the optimal schemes and the advances in IPv6. The disadvantages of the Mobile IP on solving the micro mobility problem are analyzed, on the basis of which three main proposals are discussed as the micro mobility solutions for mobile communications, including Hierarchical Mobile IP (HMIP), Cellular IP, and Handoff-Aware Wireless Access Internet Infrastructure (HAWAII). A unified model is also described in which the different micro mobility solutions can coexist simultaneously in mobile networks.

  2. Access Denied

    ERIC Educational Resources Information Center

    Villano, Matt

    2008-01-01

    Building access control (BAC)--a catchall phrase to describe the systems that control access to facilities across campus--has traditionally been handled with remarkably low-tech solutions: (1) manual locks; (2) electronic locks; and (3) ID cards with magnetic strips. Recent improvements have included smart cards and keyless solutions that make use…

  3. Open Access

    ERIC Educational Resources Information Center

    Suber, Peter

    2012-01-01

    The Internet lets us share perfect copies of our work with a worldwide audience at virtually no cost. We take advantage of this revolutionary opportunity when we make our work "open access": digital, online, free of charge, and free of most copyright and licensing restrictions. Open access is made possible by the Internet and copyright-holder…

  4. Analysis of mobile phone design features affecting radiofrequency power absorbed in a human head phantom.

    PubMed

    Kuehn, Sven; Kelsh, Michael A; Kuster, Niels; Sheppard, Asher R; Shum, Mona

    2013-09-01

    The US FCC mandates the testing of all mobile phones to demonstrate compliance with the rule requiring that the peak spatial SAR does not exceed the limit of 1.6 W/kg averaged over any 1 g of tissue. These test data, measured in phantoms with mobile phones operating at maximum antenna input power, permitted us to evaluate the variation in SARs across mobile phone design factors such as shape and antenna design, communication technology, and test date (over a 7-year period). Descriptive statistical summaries calculated for 850 MHz and 1900 MHz phones and ANOVA were used to evaluate the influence of the foregoing factors on SARs. Service technology accounted for the greatest variability in compliance test SARs that ranged from AMPS (highest) to CDMA, iDEN, TDMA, and GSM (lowest). However, the dominant factor for SARs during use is the time-averaged antenna input power, which may be much less than the maximum power used in testing. This factor is largely defined by the communication system; e.g., the GSM phone average output can be higher than CDMA by a factor of 100. Phone shape, antenna type, and orientation of a phone were found to be significant but only on the order of up to a factor of 2 (3 dB). The SAR in the tilt position was significantly smaller than for touch. The side of the head did not affect SAR levels significantly. Among the remaining factors, external antennae produced greater SARs than internal ones, and brick and clamshell phones produced greater SARs than slide phones. Assuming phone design and usage patterns do not change significantly over time, we have developed a normalization procedure and formula that permits reliable prediction of the relative SAR between various communication systems. This approach can be applied to improve exposure assessment in epidemiological research.

  5. Inclusion in an Age of Mobility

    ERIC Educational Resources Information Center

    Traxler, John

    2016-01-01

    Learning with mobiles in UK universities is not new and is not novel. It is, in fact, at least 10 years old, well-documented and comparable to activity in universities elsewhere in Western Europe, America and Asia Pacific. Continued and dramatic changes in the ownership, access and expectations of mobiles amongst university students and equally…

  6. Assessing Teaching Skills with a Mobile Simulation

    ERIC Educational Resources Information Center

    Gibson, David

    2013-01-01

    Because mobile technologies are overtaking personal computers as the primary tools of Internet access, and cloud-based resources are fundamentally transforming the world's knowledge, new forms of teaching and assessment are required to foster 21st century literacies, including those needed by K-12 teachers. A key feature of mobile technology…

  7. Connecting Learning Spaces Using Mobile Technology

    ERIC Educational Resources Information Center

    Chen, Wenli; Seow, Peter; So, Hyo-Jeong; Toh, Yancy; Looi, Chee-Kit

    2010-01-01

    The use of mobile technology can help extend children's learning spaces and enrich the learning experiences in their everyday lives where they move from one context to another, switching locations, social groups, technologies, and topics. When students have ubiquitous access to mobile devices with full connectivity, the in-situ use of the mobile…

  8. Strategies for safeguarding security of mobile computing.

    PubMed

    Green, Hays

    2013-02-01

    An effective mobile health strategy should comprise, in the very least, six key steps: Conduct a mobile security risk assessment. Establish policies and procedures. Develop a training program. Implement measures to prevent unauthorized access. Perform a clinical workflow analysis. Establish the organization's approach for responding to a breach.

  9. How To Modify a Trailer for Accessibility (Up to a Point) [and] Accessibility Considerations for Home Buyers. Key Notes.

    ERIC Educational Resources Information Center

    Access Group, Atlanta, GA.

    Two brief fact sheets for people with disabilities provide information on: (1) modifying a trailer to make it accessible for persons with mobility impairments, especially those in wheelchairs, and (2) accessibility considerations for home buyers or home owners with mobility impairments. The first fact sheet identifies inherent problems in…

  10. Equal Access.

    ERIC Educational Resources Information Center

    De Patta, Joe

    2003-01-01

    Presents an interview with Stephen McCarthy, co-partner and president of Equal Access ADA Consulting Architects of San Diego, California, about designing schools to naturally integrate compliance with the Americans with Disabilities Act (ADA). (EV)

  11. Malaysian University Students' Use of Mobile Phones for Study

    ERIC Educational Resources Information Center

    Pullen, Darren; J-F; Swabey, Karen; Abadooz, M.; Sing, Termit Kaur Ranjit

    2015-01-01

    Mobile technology coupled with Internet accessibility has increased not only how we communicate but also how we might engage in learning. The ubiquity of mobile technology, such as smart phones and tablet devices, makes it a valuable tool for accessing learning resources on the Internet. The unified theory of acceptance and use of technology…

  12. Anchor Toolkit - a secure mobile agent system

    SciTech Connect

    Mudumbai, Srilekha S.; Johnston, William; Essiari, Abdelilah

    1999-05-19

    Mobile agent technology facilitates intelligent operation insoftware systems with less human interaction. Major challenge todeployment of mobile agents include secure transmission of agents andpreventing unauthorized access to resources between interacting systems,as either hosts, or agents, or both can act maliciously. The Anchortoolkit, designed by LBNL, handles the transmission and secure managementof mobile agents in a heterogeneous distributed computing environment. Itprovides users with the option of incorporating their security managers.This paper concentrates on the architecture, features, access control anddeployment of Anchor toolkit. Application of this toolkit in a securedistributed CVS environment is discussed as a case study.

  13. Mobile Learning and Achievement Goal Orientation Profiles

    ERIC Educational Resources Information Center

    Asplund, Minna

    2014-01-01

    Students with different achievement goal orientations have different approaches towards learning and studying. There is a widespread interest to find an easy access into learning spaces for those students who have low motivation with fear of failure and academic withdrawal. Mobile learning offers an easily accessible chance with low threshold to…

  14. The Potential for Adaptable Accessible Learning Objects: A Case Study in Accessible Vodcasting

    ERIC Educational Resources Information Center

    Gkatzidou, Stavroula; Pearson, Elaine

    2009-01-01

    With the rapid development of wireless networks and mobile technologies and the increasing adoption of mobile learning, the need for "anywhere, anytime and any device" access to information becomes more evident. This has influenced the design of learning objects. The small but developing literature on vodcasting indicates its potential…

  15. Challenging Assumptions: Mobile Learning for Mathematics Project in South Africa

    ERIC Educational Resources Information Center

    Roberts, Nicky; Vanska, Riitta

    2011-01-01

    This article introduces the Nokia Mobile Learning for Mathematics Project in South Africa, which made use of mobile technology to support mathematics learning at 30 public secondary schools. It draws on the evaluation of this project from January to June 2010. The article discusses learner access to mobile devices, learner and teacher uptake and…

  16. Mobile Authoring of Open Educational Resources as Reusable Learning Objects

    ERIC Educational Resources Information Center

    Kinshuk; Jesse, Ryan

    2013-01-01

    E-learning technologies have allowed authoring and playback of standardized reusable learning objects (RLO) for several years. Effective mobile learning requires similar functionality at both design time and runtime. Mobile devices can play RLO using applications like SMILE, mobile access to a learning management system (LMS), or other systems…

  17. Prospects for the Use of Mobile Technologies in Science Education

    ERIC Educational Resources Information Center

    Avraamidou, Lucy

    2008-01-01

    During the past few years there have been great strides in the advancement of technology with the rise of mobile devices leading to an era characterized by the instant access to and mobility of information. Mobile technologies have more recently been used in a variety of educational settings for a variety of purposes and educational goals.…

  18. Mobile healthcare.

    PubMed

    Morgan, Stephen A; Agee, Nancy Howell

    2012-01-01

    Mobile technology's presence in healthcare has exploded over the past five years. The increased use of mobile devices by all segments of the US population has driven healthcare systems, providers, and payers to accept this new form of communication and to develop strategies to implement and leverage the use of mobile healthcare (mHealth) within their organizations and practices. As healthcare systems move toward a more value-driven model of care, patient centeredness and engagement are the keys to success. Mobile healthcare will provide the medium to allow patients to participate more in their care. Financially, mHealth brings to providers the ability to improve efficiency and deliver savings to both them and the healthcare consumer. However, mHealth is not without challenges. Healthcare IT departments have been reluctant to embrace this shift in technology without fully addressing security and privacy concerns. Providers have been hesitant to adopt mHealth as a form of communication with patients because it breaks with traditional models. Our healthcare system has just started the journey toward the development of mHealth. We offer an overview of the mobile healthcare environment and our approach to solving the challenges it brings to healthcare organizations.

  19. Expanding Access

    ERIC Educational Resources Information Center

    Roach, Ronald

    2007-01-01

    There is no question that the United States lags behind most industrialized nations in consumer access to broadband Internet service. For many policy makers and activists, this shortfall marks the latest phase in the struggle to overcome the digital divide. To remedy this lack of broadband affordability and availability, one start-up firm--with…

  20. Easy Access

    ERIC Educational Resources Information Center

    Gettelman, Alan

    2009-01-01

    School and university restrooms, locker and shower rooms have specific ADA accessibility requirements that serve the needs of staff, students and campus visitors who are disabled as a result of injury, illness or age. Taking good care of them is good for the reputation of a sensitive community institution, and fosters positive public relations.…

  1. Access Denied

    ERIC Educational Resources Information Center

    Raths, David

    2012-01-01

    As faculty members add online and multimedia elements to their courses, colleges and universities across the country are realizing that there is a lot of work to be done to ensure that disabled students (and employees) have equal access to course material and university websites. Unfortunately, far too few schools consider the task a top priority.…

  2. The Need to Address Mobile Device Security in the Higher Education IT Curriculum

    ERIC Educational Resources Information Center

    Patten, Karen P.; Harris, Mark A.

    2013-01-01

    Mobile devices, including smartphones and tablets, enable users to access corporate data from anywhere. In 2013, people will purchase 1.2 billion mobile devices, surpassing personal computers as the most common method for accessing the Internet. However, security of these mobile devices is a major concern for organizations. The two leading…

  3. Firewall for Dynamic IP Address in Mobile IPv6

    NASA Astrophysics Data System (ADS)

    Qiu, Ying; Bao, Feng; Zhou, Jianying

    Mobile communication is becoming the mainstream with the rapid growth of mobile devices penetrating our daily life. More and more mobile devices such as mobile phones, personal digital assistants, notebooks etc, are capable of Internet access. Mobile devices frequently change their communication IP addresses in mobile IPv6 network following its current attached domain. This raises a big challenge for building firewall for mobile devices. The conventional firewalls are primarily based on IPv4 networks where the security criteria are specified only to the fixed IP addresses or subnets, which apparently do not apply to mobile IPv6. In this paper we propose three solutions for mobile IPv6 firewall. Our approaches make the firewall adaptive to dynamic IP addresses in mobile IPv6 network. They have different expense and weight corresponding to different degree of universality. The paper focuses the study more from practical aspect.

  4. Mobility Demonstrator

    DTIC Science & Technology

    2013-08-22

    Resilient Technologies (Polaris Defense) Technology: Non- Pneumatic Tire Description: Airless Tire/wheel with honeycombed shaped polymer supporting...self-adjusting track tensioners • The biggest advancement in these systems has been pneumatic external road-arm design (external suspensions...UNCLASSIFIED: Distribution Statement A. Approved for public release. 90 Payoff:  Enabler for silent mobility, hybridization , and export power capabilities

  5. The AMSC mobile satellite system

    NASA Technical Reports Server (NTRS)

    Agnew, Carson E.; Bhagat, Jai; Hopper, Edwin A.; Kiesling, John D.; Exner, Michael L.; Melillo, Lawrence; Noreen, Gary K.; Parrott, Billy J.

    1988-01-01

    The American Mobile Satellite Consortium (AMSC) Mobile Satellite Service (MSS) system is described. AMSC will use three multi-beam satellites to provide L-band MSS coverage to the United States, Canada and Mexico. The AMSC MSS system will have several noteworthy features, including a priority assignment processor that will ensure preemptive access to emergency services, a flexible SCPC channel scheme that will support a wide diversity of services, enlarged system capacity through frequency and orbit reuse, and high effective satellite transmitted power. Each AMSC satellite will make use of 14 MHz (bi-directional) of L-band spectrum. The Ku-band will be used for feeder links.

  6. Mobile impurities in ferromagnetic liquids

    NASA Astrophysics Data System (ADS)

    Kantian, Adrian; Schollwoeck, Ulrich; Giamarchi, Thierry

    2011-03-01

    Recent work has shown that mobile impurities in one dimensional interacting systems may exhibit behaviour that differs strongly from that predicted by standard Tomonaga-Luttinger liquid theory, with the appearance of power-law divergences in the spectral function signifying sublinear diffusion of the impurity. Using time-dependent matrix product states, we investigate a range of cases of mobile impurities in systems beyond the analytically accessible examples to assess the existence of a new universality class of low-energy physics in one-dimensional systems. Correspondence: Adrian.Kantian@unige.ch This work was supported in part by the Swiss SNF under MaNEP and division II.

  7. Networking a mobile robot

    NASA Astrophysics Data System (ADS)

    McKee, Gerard T.

    1994-10-01

    Conventional mobile robotic systems are `stand alone'. Program development involves loading programs into the mobile, via an umbilical. Autonomous operation, in this context, means `isolation': the user cannot interact with the program as the robot is moving around. Recent research in `swarm robotics' has exploited wireless networks as a means of providing inter- robot communication, but the population is still isolated from the human user. In this paper we report on research we are conducting into the provision of mobile robots as resources on a local area computer network, and thus breaking the isolation barrier. We are making use of new multimedia workstation and wireless networking technology to link the robots to the network in order to provide a new type of resource for the user. We model the robot as a set of resources and propose a client-server architecture as the basis for providing user access to the robots. We describe the types of resources each robot can provide and we outline the potential for cooperative robotics, human-robot cooperation, and teleoperation and autonomous robot behavior within this context.

  8. HIV care for geographically mobile populations.

    PubMed

    Taylor, Barbara S; Garduño, L Sergio; Reyes, Emily V; Valiño, Raziel; Rojas, Rita; Donastorg, Yeycy; Brudney, Karen; Hirsch, Jennifer

    2011-01-01

    The interaction between geographic mobility and risk for human immunodeficiency virus infection is well recognized, but what happens to those same individuals, once infected, as they transition to living with the infection? Does mobility affect their transition into medical care? If so, do mobile and nonmobile populations achieve similar success with antiretroviral treatment? The definition of mobility has changed over the centuries to encompass a complex phenotype including permanent migration, frequent travel, circular migration, and travel to and from treatment centers. The heterogeneity of these definitions leads to discordant findings. Investigations show that mobility has an impact on infection risk, but fewer data exist on the impact of geographic mobility on medical care and treatment outcomes. This review will examine existing data regarding the impact of geographic mobility on access to and maintenance in medical care and on adherence to antiretroviral therapy for those living with human immunodeficiency virus infection. It will also expand the concept of mobility to include data on the impact of the distance from residence to clinic on medical care and treatment adherence. Our conclusions are that the existing literature is limited by varying definitions of mobility and the inherent oversimplification necessary to apply a "mobility measure" in a statistical analysis. The impact of mobility on antiretroviral treatment outcomes deserves further exploration to both define the phenomenon and target interventions to these at-risk populations.

  9. A service-oriented data access control model

    NASA Astrophysics Data System (ADS)

    Meng, Wei; Li, Fengmin; Pan, Juchen; Song, Song; Bian, Jiali

    2017-01-01

    The development of mobile computing, cloud computing and distributed computing meets the growing individual service needs. Facing with complex application system, it's an urgent problem to ensure real-time, dynamic, and fine-grained data access control. By analyzing common data access control models, on the basis of mandatory access control model, the paper proposes a service-oriented access control model. By regarding system services as subject and data of databases as object, the model defines access levels and access identification of subject and object, and ensures system services securely to access databases.

  10. Investigation of in-band transmission of both spectral amplitude coding/optical code division multiple-access and wavelength division multiplexing signals

    NASA Astrophysics Data System (ADS)

    Ashour, Isaac A. M.; Shaari, Sahbudin; Shalaby, Hossam M. H.; Menon, P. Susthitha

    2011-06-01

    The transmission of both optical code division multiple-access (OCDMA) and wavelength division multiplexing (WDM) users on the same band is investigated. Code pulses of spectral amplitude coding (SAC)/optical code division multiple-access (CDMA) are overlaid onto a multichannel WDM system. Notch filters are utilized in order to suppress the WDM interference signals for detection of optical broadband CDMA signals. Modified quadratic congruence (MQC) codes are used as the signature codes for the SAC/OCDMA system. The proposed system is simulated and its performance in terms of both the bit-error rate and Q-factor are determined. In addition, eavesdropper probability of error-free code detection is evaluated. Our results are compared to traditional nonhybrid systems. It is concluded that the proposed hybrid scheme still achieves acceptable performance. In addition, it provides enhanced data confidentiality as compared to the scheme with SAC/OCDMA only. It is also shown that the performance of the proposed system is limited by the interference of the WDM signals. Furthermore, the simulation illustrates the tradeoff between the performance and confidentiality for authorized users.

  11. Hemodialysis access - self care

    MedlinePlus

    Kidney failure - chronic-hemodialysis access; Renal failure - chronic-hemodialysis access; Chronic renal insufficiency - hemodialysis access; Chronic kidney failure - hemodialysis access; Chronic renal failure - hemodialysis access; dialysis - hemodialysis ...

  12. Does urban sprawl hold down upward mobility?

    USGS Publications Warehouse

    Ewing, R.; Hamidi, Shima; Grace, James B.; Wei, Y.

    2016-01-01

    Contrary to the general perception, the United States has a much more class-bound society than other wealthy countries. The chance of upward mobility for Americans is just half that of the citizens of the Denmark and many other European countries. In addition to other influences, the built environment may contribute to the low rate of upward mobility in the U.S. This study tests the relationship between urban sprawl and upward mobility for commuting zones in the U.S. We examine potential pathways through which sprawl may have an effect on mobility. We use structural equation modeling to account for both direct and indirect effects of sprawl on upward mobility. We find that upward mobility is significantly higher in compact areas than sprawling areas. The direct effect, which we attribute to better job accessibility in more compact commuting zones, is stronger than the indirect effects. Of the indirect effects, only one, through the mediating variable income segregation, is significant.

  13. Mobile Customer Relationship Management and Mobile Security

    NASA Astrophysics Data System (ADS)

    Sanayei, Ali; Mirzaei, Abas

    The purpose of this study is twofold. First, in order to guarantee a coherent discussion about mobile customer relationship management (mCRM), this paper presents a conceptualization of mCRM delineating its unique characteristics because of Among the variety of mobile services, considerable attention has been devoted to mobile marketing and in particular to mobile customer relationship management services. Second, the authors discusses the security risks in mobile computing in different level(user, mobile device, wireless network,...) and finally we focus on enterprise mobile security and it's subgroups with a series of suggestion and solution for improve mobile computing security.

  14. Systems implications of L-band fade data statistics for LEO mobile systems

    NASA Technical Reports Server (NTRS)

    Devieux, Carrie L.

    1993-01-01

    This paper examines and analyzes research data on the role of foliage attenuation in signal fading between a satellite transmitter and a terrestrial vehicle-mounted receiver. The frequency band of measurement, called L-Band, includes the region 1610.0 to 1626.5 MHz. Data from tests involving various combinations of foliage and vehicle movement conditions clearly show evidence of fast fading (in excess of 0.5 dB per millisecond) and fade depths as great or greater than 16 dB. As a result, the design of a communications link power control that provides the level of accuracy necessary for power sensitive systems could be significantly impacted. Specific examples of this include the communications links that employ Code Division Multiple Access (CDMA) as a modulation technique.

  15. Mobile medical visual information retrieval.

    PubMed

    Depeursinge, Adrien; Duc, Samuel; Eggel, Ivan; Müller, Henning

    2012-01-01

    In this paper, we propose mobile access to peer-reviewed medical information based on textual search and content-based visual image retrieval. Web-based interfaces designed for limited screen space were developed to query via web services a medical information retrieval engine optimizing the amount of data to be transferred in wireless form. Visual and textual retrieval engines with state-of-the-art performance were integrated. Results obtained show a good usability of the software. Future use in clinical environments has the potential of increasing quality of patient care through bedside access to the medical literature in context.

  16. Mobility Bibliography.

    DTIC Science & Technology

    1981-11-01

    Abele, G.; Walker, D.A.; Brown, J .; Brewer, M.C.; Atwood, D.M. TI - Effects of low ground pressure vehicle traffic on tundra aL Lonely, Alaska SO...resistance, bulldozing resistance. NTIS ’ DT ’ . [ Acces. J "D-4 CONTENTS Chapter I Snow vehicles or snowmobiles Chapter II Rolling resistance Chapter III...Russian Swe Swedish Eng English Jap Japanese Ger German Pol Polish Czech Czechoslovakian Nor Norwegian P reface This mobility bibliography was

  17. Going mobile

    NASA Astrophysics Data System (ADS)

    Brus, Eric

    1987-12-01

    By 1990, all metropolitan areas in the U.S. and rural areas close to major cities or towns are expected to have cellular telephone service; 22 Canadian cities also feature cellular service. To supply mobile telecommunication services to sparsely-populated rural areas, a mobile satellite service (MSS) is now being developed. In this paper the projected possibilities of the MSS system are discussed, including a possibility that a piggyback-MSS payload be added to the GSTAR-4 satellite which is scheduled for a launch in 1988 or 1989; one in which some of the hardware from aborted direct-broadcast satellites would be used; and the possibility of building a new MSS satellite with large servicing capacity. Canada is planning to launch its own mobile satellite, MSAT, in the early 1990s. The MSS is expected to be 'generic', serving not only people on land but maritime and aeronautical users as well. It will also offer major benefits to truck and automobile drivers, making it possible for them to conduct business or to call for assistance from locations beyond the range of cellular systems.

  18. Mobile Thread Task Manager

    NASA Technical Reports Server (NTRS)

    Clement, Bradley J.; Estlin, Tara A.; Bornstein, Benjamin J.

    2013-01-01

    The Mobile Thread Task Manager (MTTM) is being applied to parallelizing existing flight software to understand the benefits and to develop new techniques and architectural concepts for adapting software to multicore architectures. It allocates and load-balances tasks for a group of threads that migrate across processors to improve cache performance. In order to balance-load across threads, the MTTM augments a basic map-reduce strategy to draw jobs from a global queue. In a multicore processor, memory may be "homed" to the cache of a specific processor and must be accessed from that processor. The MTTB architecture wraps access to data with thread management to move threads to the home processor for that data so that the computation follows the data in an attempt to avoid L2 cache misses. Cache homing is also handled by a memory manager that translates identifiers to processor IDs where the data will be homed (according to rules defined by the user). The user can also specify the number of threads and processors separately, which is important for tuning performance for different patterns of computation and memory access. MTTM efficiently processes tasks in parallel on a multiprocessor computer. It also provides an interface to make it easier to adapt existing software to a multiprocessor environment.

  19. TissueWiki(Mobile): an Integrative Protein Expression Image Browser for Pathological Knowledge Sharing and Annotation on a Mobile Device.

    PubMed

    Cheng, Chihwen; Stokes, Todd H; Hang, Sovandy; Wang, May D

    2010-12-01

    Doctors need fast and convenient access to medical data. This motivates the use of mobile devices for knowledge retrieval and sharing. We have developed TissueWiki(Mobile) on the Apple iPhone and iPad to seamlessly access TissueWiki, an enormous repository of medical histology images. TissueWiki is a three terabyte database of antibody information and histology images from the Human Protein Atlas (HPA). Using TissueWiki(Mobile), users are capable of extracting knowledge from protein expression, adding annotations to highlight regions of interest on images, and sharing their professional insight. By providing an intuitive human computer interface, users can efficiently operate TissueWiki(Mobile) to access important biomedical data without losing mobility. TissueWiki(Mobile) furnishes the health community a ubiquitous way to collaborate and share their expert opinions not only on the performance of various antibodies stains but also on histology image annotation.

  20. Design of variable-weight quadratic congruence code for optical CDMA

    NASA Astrophysics Data System (ADS)

    Feng, Gang; Cheng, Wen-Qing; Chen, Fu-Jun

    2015-09-01

    A variable-weight code family referred to as variable-weight quadratic congruence code (VWQCC) is constructed by algebraic transformation for incoherent synchronous optical code division multiple access (OCDMA) systems. Compared with quadratic congruence code (QCC), VWQCC doubles the code cardinality and provides the multiple code-sets with variable code-weight. Moreover, the bit-error rate (BER) performance of VWQCC is superior to those of conventional variable-weight codes by removing or padding pulses under the same chip power assumption. The experiment results show that VWQCC can be well applied to the OCDMA with quality of service (QoS) requirements.

  1. Adaptive Behavior for Mobile Robots

    NASA Technical Reports Server (NTRS)

    Huntsberger, Terrance

    2009-01-01

    The term "System for Mobility and Access to Rough Terrain" (SMART) denotes a theoretical framework, a control architecture, and an algorithm that implements the framework and architecture, for enabling a land-mobile robot to adapt to changing conditions. SMART is intended to enable the robot to recognize adverse terrain conditions beyond its optimal operational envelope, and, in response, to intelligently reconfigure itself (e.g., adjust suspension heights or baseline distances between suspension points) or adapt its driving techniques (e.g., engage in a crabbing motion as a switchback technique for ascending steep terrain). Conceived for original application aboard Mars rovers and similar autonomous or semi-autonomous mobile robots used in exploration of remote planets, SMART could also be applied to autonomous terrestrial vehicles to be used for search, rescue, and/or exploration on rough terrain.

  2. Proceedings of the Fifth International Mobile Satellite Conference 1997

    NASA Technical Reports Server (NTRS)

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

    1997-01-01

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

  3. Accessibility and ergonomic analysis for banking cash.

    PubMed

    Kaizer, A; Ramos, F; Ferro, E

    2012-01-01

    Ergonomics and accessibility in banking has been the subject of numerous discussions, and in this work proposed by the partnership of companies and NR TN Mobile Work Safety and Occupational Medicine, aimed to analyze the service box and propose the development of a project to the teller accessible account of both the legal aspects regarding the factors inherent in banking, focusing primarily on the interface of the worker and the client user.

  4. DETAIL VIEW OF THE PORT TSM ACCESS DOOR Cape ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    DETAIL VIEW OF THE PORT TSM ACCESS DOOR - Cape Canaveral Air Force Station, Launch Complex 39, Mobile Launcher Platforms, Launcher Road, East of Kennedy Parkway North, Cape Canaveral, Brevard County, FL

  5. High precision mobile location framework and its service based on virtual reference station of GPS

    NASA Astrophysics Data System (ADS)

    Liu, Chun; Sun, Liangyu; Yao, Lianbi

    2008-10-01

    The wireless communication technology and space technology are synchronously developed in recent years, which bring up the development of location based service (LBS). At present, many location technology methods were developed. However, all these methods can only provide a relative poor location precision and depend on high cost. The technology of Virtual Reference Station (VRS) of GPS is then involved in this paper. One of the objective in this paper is aim to give the LBS position structure to improve the mobile location position when a mobile position instrument is connected with VRS network. The cheaper GPS built-in Personal Designer Aid (PDA) is then used to achieve a higher precision by using RTCM data from existing VRS network. In order to obtain a high precision position when using the low-cost GPS receiver as a rover, the infrusture of the mobile differential correction system is then put forward. According to network transportation of RTCM via internet protocol (NTRIP), the message is communicated through wireless network, such as GPRS, CDMA and so on. The rough coordinate information is sent to VRS control center continuously, and then the VRS correction information is replied to rover in the data format of RTCM3.1. So the position will be updated based on mathematic solution after the decoding of RTCM3.1 data. The thought of LBS position can improve the precision, and can speed the LBS.

  6. A Secure Operational Model for Mobile Payments

    PubMed Central

    2014-01-01

    Instead of paying by cash, check, or credit cards, customers can now also use their mobile devices to pay for a wide range of services and both digital and physical goods. However, customers' security concerns are a major barrier to the broad adoption and use of mobile payments. In this paper we present the design of a secure operational model for mobile payments in which access control is based on a service-oriented architecture. A customer uses his/her mobile device to get authorization from a remote server and generate a two-dimensional barcode as the payment certificate. This payment certificate has a time limit and can be used once only. The system also provides the ability to remotely lock and disable the mobile payment service. PMID:25386607

  7. Device Data Protection in Mobile Healthcare Applications

    NASA Astrophysics Data System (ADS)

    Weerasinghe, Dasun; Rajarajan, Muttukrishnan; Rakocevic, Veselin

    The rapid growth in mobile technology makes the delivery of healthcare data and services on mobile phones a reality. However, the healthcare data is very sensitive and has to be protected against unauthorized access. While most of the development work on security of mobile healthcare today focuses on the data encryption and secure authentication in remote servers, protection of data on the mobile device itself has gained very little attention. This paper analyses the requirements and the architecture for a secure mobile capsule, specially designed to protect the data that is already on the device. The capsule is a downloadable software agent with additional functionalities to enable secure external communication with healthcare service providers, network operators and other relevant communication parties.

  8. A secure operational model for mobile payments.

    PubMed

    Chang, Tao-Ku

    2014-01-01

    Instead of paying by cash, check, or credit cards, customers can now also use their mobile devices to pay for a wide range of services and both digital and physical goods. However, customers' security concerns are a major barrier to the broad adoption and use of mobile payments. In this paper we present the design of a secure operational model for mobile payments in which access control is based on a service-oriented architecture. A customer uses his/her mobile device to get authorization from a remote server and generate a two-dimensional barcode as the payment certificate. This payment certificate has a time limit and can be used once only. The system also provides the ability to remotely lock and disable the mobile payment service.

  9. Mobile Botnet Detection Using Network Forensics

    NASA Astrophysics Data System (ADS)

    Vural, Ickin; Venter, Hein

    Malicious software (malware) infects large numbers of computers around the world. This malware can be used to promote unwanted products, disseminate offensive content, or provide unauthorized access to personal and financial information. Until recently mobile networks have been relatively isolated from the Internet, so there has been little need to protect them against Botnets. Mobile networks are now well integrated with the internet, so threats on the internet such as Botnets have started to migrate onto mobile networks. Botnets on mobile devices will probably appear very soon, there are already signs that this is happening. This paper studies the potential threat of Botnets based on mobile networks, and proposes the use of computational intelligence techniques to detect Botnets. We then simulate anomaly detection followed by an interpretation of the simulated values.

  10. Mobile Learning in Medical Education: Review.

    PubMed

    Walsh, Kieran

    2015-10-01

    In the past several years, mobile learning made rapid inroads into the provision of medical education. There are significant advantages associated with mobile learning. These include high access, low cost, more situated and contextual learning, convenience for the learner, continuous communication and interaction between learner and tutor and between learner and other learners, and the ability to self-assess themselves while learning. Like any other form of medical pedagogy, mobile learning has its downsides. Disadvantages of mobile learning include: inadequate technology, a risk of distraction from learning by using a device that can be used for multiple purposes, and the potential for breakdown in barriers between personal usage of the mobile device and professional or educational use. Despite these caveats, there is no question but that mobile learning offers much potential. In the future, it is likely that the strategy of mobile first, whereby providers of e-learning think of the user experience on a mobile first, will result in learners who increasingly expect that all e-learning provision will work seamlessly on a mobile device.

  11. PAPR reduction in synchronous CI/MC-CDMA uplink system using genetic algorithms

    NASA Astrophysics Data System (ADS)

    Hati, Sumanta; Maity, Santi P.

    2013-01-01

    Main disadvantage of a multicarrier communication system is high peak to average power ratio (PAPR) of the transmitted signal. The high PAPR causes the performance degradation due to nonlinear distortion in the high power amplifier (HPA). PAPR value is closely depends on transmitted power and correlation properties of the user's spreading code. High peak and low average value of the transmitted power increases the PAPR. On the other side high auto correlation function (ACF) value and low cross correlation function (CCF) value of the spreading code also increases the PAPR. But to eliminate the multiple access interference (MAI) in receiver end, ACF should be peak and CCF should be posses zero for all time shifts. So, there is a conflicting nature of PAPR and bit error rate (BER). That's why an exhaustive effort has been made in this paper for proper distribution of transmitted power within an acceptable range of peak transmitted power and evaluates the new spreading codes using Genetic Algorithms (GA). In general, to obtain optimum PAPR reduction using GA, total searching time to find out the proper amplitude and phase parameters must be accomplished. Simulation results show that PAPR and BER performance using this proposed technique is better than conventional network.

  12. Optical CDMA with Embedded Spectral-Polarization Coding over Double Balanced Differential-Detector

    NASA Astrophysics Data System (ADS)

    Huang, Jen-Fa; Yen, Chih-Ta; Chen, Bo-Hau

    A spectral-polarization coding (SPC) optical code-division multiple-access (OCDMA) configuration structured over arrayed-waveguide grating (AWG) router is proposed. The polarization-division double balanced detector is adopted to execute difference detection and enhances system performance. The signal-to-noise ratio (SNR) is derived by taking the effect of PIIN into account. The result indicates that there would be up to 9-dB SNR improvement than the conventional spectral-amplitude coding (SAC) structures with Walsh-Hadamard codes. Mathematical deriving results of the SNR demonstrate the system embedded with the orthogonal state of polarization (SOP) will suppress effectively phase-induced intensity noise (PIIN). In addition, we will analyze the relations about bit error rate (BER) vs. the number of active users under the different encoding schemes and compare them with our proposed scheme. The BER vs. the effective power under the different encoding scheme with the same number of simultaneous active user conditions are also revealed. Finally, the polarization-matched factor and the difference between simulated and experimental values are discussed.

  13. Privacy and Security in Mobile Health: A Research Agenda

    PubMed Central

    Kotz, David; Gunter, Carl A.; Kumar, Santosh; Weiner, Jonathan P.

    2017-01-01

    Mobile health technology has great potential to increase healthcare quality, expand access to services, reduce costs, and improve personal wellness and public health. However, mHealth also raises significant privacy and security challenges. PMID:28344359

  14. Privacy and Security in Mobile Health: A Research Agenda.

    PubMed

    Kotz, David; Gunter, Carl A; Kumar, Santosh; Weiner, Jonathan P

    2016-06-01

    Mobile health technology has great potential to increase healthcare quality, expand access to services, reduce costs, and improve personal wellness and public health. However, mHealth also raises significant privacy and security challenges.

  15. Situational Effects on the Usage Intention of Mobile Games

    NASA Astrophysics Data System (ADS)

    Liang, Ting-Peng; Yeh, Yi-Hsuan

    As value-added services on mobile devices are developing rapidly, text messaging, multi-media messaging, music, video, games, GPS navigation, RFID, and mobile TV are all accessible from a single device. Mobile games that combine mobile communication with computer games are an emerging industry. The purpose of this research is to explore what situation factors may affect the intention to play mobile game. We propose a research model to fit the nature of mobile games and conducted an online survey to examine the effect of situational factors. The model integrates constructs in TAM and TRA. The findings are as follows. First, Subjective norm affects a user’s intention in using mobile games when a user has no other task. Second, perceived playfulness affects a user’s intention to use mobile games when the user has another task.

  16. Understanding energy consumption of sensor enabled applications on mobile phones.

    PubMed

    Crk, Igor; Albinali, Fahd; Gniady, Chris; Hartman, John

    2009-01-01

    Recent research in ubiquitous and mobile computing uses mobile phones and wearable accelerometers to monitor individuals' physical activities for personalized and proactive health care. The goal of this project is to measure and reduce the energy demand placed on mobile phones that monitor individuals' physical activities for extended periods of time with limited access to battery recharging and mobile phone reception. Many issues must be addressed before mobile phones become a viable platform for remote health monitoring, including: security, reliability, privacy, and, most importantly, energy. Mobile phones are battery-operated, making energy a critical resource that must be carefully managed to ensure the longest running time before the battery is depleted. In a sense, all other issues are secondary, since the mobile phone will simply not function without energy. In this project, we therefore focus on understanding the energy consumption of a mobile phone that runs MIT wockets, physical activity monitoring applications, and consider ways to reduce its energy consumption.

  17. Volume 4 - Mobile Sources

    EPA Pesticide Factsheets

    Mobile source reference material for activity data collection from the Emissions Inventory Improvement Program (EIIP). Provides complete methods for collecting key inputs to onroad mobile and nonroad mobile emissions models.

  18. Simultaneous CDMA and error correction schemes based on wavelet filters in integer quotient rings

    NASA Astrophysics Data System (ADS)

    Lay, Kuen-Tsair; Kong, Lin-Wen; Chen, Jiann-Horng

    2000-04-01

    In the past decade, wavelet filters have been widely applied to signal processing. In effect, wavelet filters are perfect reconstruction filter banks (PRFBs). However, in most researches, the filterbanks and wavelets operate on real- valued or complex-valued signals. In this paper, PRFBs operating over integer quotient rings (IQRs) are introduced. We denote an IQR as Z/(q). Algorithms for constructing such filter banks are proposed. The PRFB design can be carried out either in the time or the frequency domain. We demonstrate that some classical or well known filter tap coefficients can even be transformed into values over Z/(q) in a simple and straightforward way. Here we emphasize that to achieve perfect reconstruction (PR), the filters need not to work on elements in fields. In fact, operating on elements in IQRs can achieve PR with proper choices of a ring and filter tap coefficients. The designed filter banks can be orthogonal or biorthogonal. Based ona PRFB over an IQR, to which we refer as an IQR-PRFB, a perfect reconstruction transmultiplexer (PRTM), to which we refer as an IQR-PRTM, can be derived. Through the utilization of the IQR-PRTM multiplexing and multiple access in a multi-user digital communication system can be realized. The IQR-PRTM effectively decomposes the communication signal space into several orthogonal subspaces, where each multiplexed user sends his message in one of them. If some of the orthogonal subspaces are preserved for parity check, then error correction at the receiving end can be performed. In the proposed schemes, the data to be transmitted must be represented with elements of Z/(q), which can be done easily. A modulation and demodulation/detection scheme, in conjunction with the IQR-PRTM is proposed.

  19. Library support of mobile resources during clinical clerkships.

    PubMed

    Stokes, Alice; Light, Jeanene; Haines, Laura L

    2014-01-01

    In response to frequent use of mobile devices among medical students, Dana Medical Library at the University of Vermont provided mobile resource support to medical students preparing for clerkships. The librarians offered group instruction, individual assistance, and an online subject guide. These activities were assessed through evaluations, web statistics, and a survey. Survey questions gathered data on access to mobile devices, use of library-licensed mobile resources, and benefits and barriers to use in the clinical setting. The majority of survey respondents believed access to mobile resources improved their clerkship experience and contributed to comparable educational experiences across clerkship sites. Researchers found that library support affected student perception of the value of mobile resources in the clerkship experience.

  20. Cooperating mobile robots

    DOEpatents

    Harrington, John J.; Eskridge, Steven E.; Hurtado, John E.; Byrne, Raymond H.

    2004-02-03

    A miniature mobile robot provides a relatively inexpensive mobile robot. A mobile robot for searching an area provides a way for multiple mobile robots in cooperating teams. A robotic system with a team of mobile robots communicating information among each other provides a way to locate a source in cooperation. A mobile robot with a sensor, a communication system, and a processor, provides a way to execute a strategy for searching an area.

  1. Improving vaccine registries through mobile technologies: a vision for mobile enhanced Immunization information systems.

    PubMed

    Wilson, Kumanan; Atkinson, Katherine M; Deeks, Shelley L; Crowcroft, Natasha S

    2016-01-01

    Immunization registries or information systems are critical to improving the quality and evaluating the ongoing success of immunization programs. However, the completeness of these systems is challenged by a myriad of factors including the fragmentation of vaccine administration, increasing mobility of individuals, new vaccine development, use of multiple products, and increasingly frequent changes in recommendations. Mobile technologies could offer a solution, which mitigates some of these challenges. Engaging individuals to have more control of their own immunization information using their mobile devices could improve the timeliness and accuracy of data in central immunization information systems. Other opportunities presented by mobile technologies that could be exploited to improve immunization information systems include mobile reporting of adverse events following immunization, the capacity to scan 2D barcodes, and enabling bidirectional communication between individuals and public health officials. Challenges to utilizing mobile solutions include ensuring privacy of data, access, and equity concerns, obtaining consent and ensuring adoption of technology at sufficiently high rates. By empowering individuals with their own health information, mobile technologies can also serve as a mechanism to transfer immunization information as individuals cross local, regional, and national borders. Ultimately, mobile enhanced immunization information systems can help realize the goal of the individual, the healthcare provider, and public health officials always having access to the same immunization information.

  2. Mobile Schools for a Mobile World

    ERIC Educational Resources Information Center

    Booth, Susan

    2013-01-01

    Overwhelmingly, independent schools are embracing mobile devices--laptops, iPads or other tablets, and smartphones--to enhance teaching and learning. This article describes the results of the "NAIS 2012 Mobile Learning Survey." Among its findings were that 75 percent of NAIS-member schools currently use mobile learning devices in at…

  3. Mobile applications and Virtual Observatory

    NASA Astrophysics Data System (ADS)

    Schaaff, A.; Jagade, S.

    2015-06-01

    Within a few years, smartphones and Internet tablets have become the devices to access Web or standalone applications from everywhere, with a rapid development of the bandwidth of the mobile networks (e.g. 4G). Internet tablets are used to take notes during meetings or conferences, to read scientific papers in public transportation, etc. A smartphone is for example a way to have your data in the pocket or to control, from everywhere, the progress of a heavy workflow process. These mobile devices have enough powerful hardware to run more and more complex applications for many use cases. In the field of astronomy it is possible to use these tools to access data via a simple browser, but also to develop native applications reusing libraries (written in Java for Android or Objective-C/Swift for iOS) developed for desktops/laptops. We describe the experiments conducted in this domain, at CDS and IUCAA, considering a mobile application as a native application as well as a Web application.

  4. 6. MOBILE LAUNCHER SIDE 4, SHOWING MILK STOOL AND LUT. ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    6. MOBILE LAUNCHER SIDE 4, SHOWING MILK STOOL AND LUT. PROTRUSION ON UPPER RIGHT HAND SIDE OF LUT IS SWING ARM NINE WHICH PROVIDED ACCESS TO CAPSULE OF LAUNCH VEHICLE WHILE ON LAUNCHER. - Mobile Launcher One, Kennedy Space Center, Titusville, Brevard County, FL

  5. Statistical Inference-Based Cache Management for Mobile Learning

    ERIC Educational Resources Information Center

    Li, Qing; Zhao, Jianmin; Zhu, Xinzhong

    2009-01-01

    Supporting efficient data access in the mobile learning environment is becoming a hot research problem in recent years, and the problem becomes tougher when the clients are using light-weight mobile devices such as cell phones whose limited storage space prevents the clients from holding a large cache. A practical solution is to store the cache…

  6. Student Use and Pedagogical Impact of a Mobile Learning Application

    ERIC Educational Resources Information Center

    Teri, Saskia; Acai, Anita; Griffith, Douglas; Mahmoud, Qusay; Ma, David W. L.; Newton, Genevieve

    2014-01-01

    Mobile learning (m-learning) is a relevant innovation in teaching and learning in higher education. A mobile app called NutriBiochem was developed for use in biochemistry and nutrition education for students in a second year Biochemistry and Metabolism course. NutriBiochem was accessed through smartphones, tablets, or computers. Students were…

  7. A Mobile Learning Overview by Timeline and Mind Map

    ERIC Educational Resources Information Center

    Parsons, David

    2014-01-01

    Mobile learning has been a research topic for some 20 years. Over that time it has encompassed a wide range of concepts, theories, designs, experiments and evaluations. With increasing interest in mobile learning from researchers and practitioners, an accessible overview of this area of research that encapsulates its many facets and features can…

  8. Evaluation of Mobile Authoring and Tutoring in Medical Issues

    ERIC Educational Resources Information Center

    Alepis, Efthymios; Virvou, Maria

    2010-01-01

    Mobile computing facilities may provide many assets to the educational process. Mobile technology provides software access from anywhere and at any time, as well as computer equipment independence. The need for time and place independence is even greater for medical instructors and medical students. Medical instructors are usually doctors that…

  9. Mobile Technology: Implications of Its Application on Learning

    ERIC Educational Resources Information Center

    Adeyemo, Samuel Adesola; Adedoja, Gloria Olusola; Adelore, Omobola

    2013-01-01

    Learning in Nigeria is considered to have taken a new dimension as the Distance Learning Centre (DLC) of the University of Ibadan has created wider access to learning through the application of mobile technology to learning with particular reference to mobile phones use for the teaching and learning process. By this, the Centre seeks to achieve…

  10. SyRoTek--Distance Teaching of Mobile Robotics

    ERIC Educational Resources Information Center

    Kulich, M.; Chudoba, J.; Kosnar, K.; Krajnik, T.; Faigl, J.; Preucil, L.

    2013-01-01

    E-learning is a modern and effective approach for training in various areas and at different levels of education. This paper gives an overview of SyRoTek, an e-learning platform for mobile robotics, artificial intelligence, control engineering, and related domains. SyRoTek provides remote access to a set of fully autonomous mobile robots placed in…

  11. Anthropometry and Standards for Wheeled Mobility: An International Comparison

    ERIC Educational Resources Information Center

    Steinfeld, Edward; Maisel, Jordana; Feathers, David; D'Souza, Clive

    2010-01-01

    Space requirements for accommodating wheeled mobility devices and their users in the built environment are key components of standards for accessible design. These requirements typically include dimensions for clear floor areas, maneuvering clearances, seat and knee clearance heights, as well as some reference dimensions on wheeled mobility device…

  12. Understanding and Capturing People’s Mobile App Privacy Preferences

    DTIC Science & Technology

    2013-10-28

    they collect might also include personal information such as users’ location, phone number, etc. Similar to targeted advertising libraries, mobile ...The percentage of users surprised about popular mobile apps using users’ location, phone ID and contact list. This figure shows the top 10 apps with...surprised by these popular mobile apps access users’ location, unique phone ID and contact list. Figure 17 shows the data related to the top 10 apps

  13. Making the World Wide Web Accessible to All Students.

    ERIC Educational Resources Information Center

    Guthrie, Sally A.

    2000-01-01

    Examines the accessibility of Web sites belonging to 80 colleges of communications and schools of journalism by examining the hypertext markup language (HTML) used to format the pages. Suggests ways to revise the markup of pages to make them more accessible to students with vision, hearing, and mobility problems. Lists resources of the latest…

  14. 46 CFR 108.165 - Access to lifeboats and liferafts.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ....165 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) A-MOBILE OFFSHORE DRILLING UNITS DESIGN AND EQUIPMENT Construction and Arrangement Means of Escape § 108.165 Access to lifeboats and liferafts. Each unit must be designed to provide direct access to the lifeboat and liferaft...

  15. 46 CFR 108.165 - Access to lifeboats and liferafts.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ....165 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) A-MOBILE OFFSHORE DRILLING UNITS DESIGN AND EQUIPMENT Construction and Arrangement Means of Escape § 108.165 Access to lifeboats and liferafts. Each unit must be designed to provide direct access to the lifeboat and liferaft...

  16. Neurolinguistic Programming in Orientation and Mobility.

    ERIC Educational Resources Information Center

    Williams, M. F.; Jacobson, W. H.

    1989-01-01

    The article describes the neurolinguistic programing model and applies it to teaching orientation and mobility skills to congenitally blind students, who have access to only the auditory and kinesthetic primary systems. Understanding the effects on thought of limited representational systems can help trainers teach more effective cane or dog guide…

  17. 7 CFR 1755.509 - Mobile homes.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... TELECOMMUNICATIONS POLICIES ON SPECIFICATIONS, ACCEPTABLE MATERIALS, AND STANDARD CONTRACT FORMS § 1755.509 Mobile... applied. (b) The method of customer access location installation prescribed by the ANSI/NFPA 70-1999, NEC... ANSI/NFPA 70-1999, NEC ®, is incorporated by reference in accordance with 5 U.S.C. 552(a) and 1...

  18. 7 CFR 1755.509 - Mobile homes.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... TELECOMMUNICATIONS POLICIES ON SPECIFICATIONS, ACCEPTABLE MATERIALS, AND STANDARD CONTRACT FORMS § 1755.509 Mobile... applied. (b) The method of customer access location installation prescribed by the ANSI/NFPA 70-1999, NEC... ANSI/NFPA 70-1999, NEC ®, is incorporated by reference in accordance with 5 U.S.C. 552(a) and 1...

  19. 7 CFR 1755.509 - Mobile homes.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... TELECOMMUNICATIONS POLICIES ON SPECIFICATIONS, ACCEPTABLE MATERIALS, AND STANDARD CONTRACT FORMS § 1755.509 Mobile... applied. (b) The method of customer access location installation prescribed by the ANSI/NFPA 70-1999, NEC... ANSI/NFPA 70-1999, NEC ®, is incorporated by reference in accordance with 5 U.S.C. 552(a) and 1...

  20. 7 CFR 1755.509 - Mobile homes.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... TELECOMMUNICATIONS POLICIES ON SPECIFICATIONS, ACCEPTABLE MATERIALS, AND STANDARD CONTRACT FORMS § 1755.509 Mobile... applied. (b) The method of customer access location installation prescribed by the ANSI/NFPA 70-1999, NEC... ANSI/NFPA 70-1999, NEC ®, is incorporated by reference in accordance with 5 U.S.C. 552(a) and 1...

  1. Mobile devices as adjunctive pain management tools.

    PubMed

    Wiederhold, Brenda K; Gao, Kenneth; Kong, Lingjun; Wiederhold, Mark D

    2014-06-01

    Approximately 108 million people in North America and Europe suffer from chronic pain. Virtual reality (VR) is a promising method for pain management in a clinical setting due to the distracting properties of an immersive virtual environment. In this study, we demonstrated the potential use of mobile phones as a means of delivering an easily accessible, immersive experience. Thirty-one patients tested VR pain distraction. Objective measurements of heart rate correlated to decreased anxiety, while, subjectively, patients also reported reduced levels of discomfort. The positive results of this study indicate that mobile phones can provide an immersive experience sufficient to deliver pain management distraction. Because mobile devices are widely available, the potential for developing pain management programs that are accessible has become a realistic possibility.

  2. Ubiquitous Learning Website: Scaffold Learners by Mobile Devices with Information-Aware Techniques

    ERIC Educational Resources Information Center

    Chen, G. D.; Chang, C. K.; Wang, C. Y.

    2008-01-01

    The portability and immediate communication properties of mobile devices influence the learning processes in interacting with peers, accessing resources and transferring data. For example, the short message and browsing functions in a cell phone provide users with timely and adaptive information access. Although many studies of mobile learning…

  3. 75 FR 33303 - Comment Sought on Measurement of Mobile Broadband Network Performance and Coverage

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-06-11

    ... significance of mobile internet access. Additionally, the Bureau seeks comment on how providers can improve... services given the growing significance of mobile internet access. Additionally, the Bureau seeks comment... the following methods: Electronic Filers: Comments may be filed electronically using the Internet...

  4. The Effects of Locus of Control on University Students' Mobile Learning Adoption

    ERIC Educational Resources Information Center

    Hsia, Jung-Wen

    2016-01-01

    Since mobile devices have become cheaper, easily accessible, powerful, and popular and the cost of wireless access has declined gradually, mobile learning (m-learning) has begun to spread rapidly. To further improve the effectiveness and efficiency of m-learning for university students, it is critical to understand whether they use m-learning.…

  5. Hemodialysis access procedures

    MedlinePlus

    ... returned to your body. Usually the access is put in your arm but it can also go ... A surgeon will put the access in. There are 3 types of access. Fistula: The surgeon joins an artery and vein under the ...

  6. 78 FR 9605 - Operation of Wireless Communications Services in the 2.3 GHz Band; Establishment of Rules and...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-02-11

    ...) and aeronautical mobile telemetry (AMT) operations in adjacent bands and the deep space network (DSN... (user device to base station) transmission technology (e.g., 3rd Generation Partnership Project Long... Access (W-CDMA)--spread user devices' signals across the channel bandwidth and control the power of...

  7. 47 CFR 25.254 - Special requirements for ancillary terrestrial components operating in the 1610-1626.5 MHz/2483.5...

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... bandwidth of one megahertz or equivalent and no less video bandwidth shall be used to measure wideband EIRP... Mobile Satellite Service (MSS) Networks Utilizing Code Division Multiple Access (CDMA) and Other Spread... unacceptable interference to systems identified in paragraph (c) of this section and, in any case, shall...

  8. 47 CFR 25.254 - Special requirements for ancillary terrestrial components operating in the 1610-1626.5 MHz/2483.5...

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... bandwidth of one megahertz or equivalent and no less video bandwidth shall be used to measure wideband EIRP... Mobile Satellite Service (MSS) Networks Utilizing Code Division Multiple Access (CDMA) and Other Spread... unacceptable interference to systems identified in paragraph (c) of this section and, in any case, shall...

  9. Ubiquitous Mobile Awareness from Sensor Networks

    NASA Astrophysics Data System (ADS)

    Kanter, Theo; Pettersson, Stefan; Forsström, Stefan; Kardeby, Victor; Österberg, Patrik

    Users require applications and services to be available everywhere, enabling them to focus on what is important to them. Therefore, context information (e.g., spatial data, user preferences, available connectivity and devices, etc.) has to be accessible to applications that run in end systems close to users. In response to this, we present a novel architecture for ubiquitous sensing and sharing of context in mobile services and applications. The architecture offers distributed storage of context derived from sensor networks wirelessly attached to mobile phones and other devices. The architecture also handles frequent updates of sensor information and is interoperable with presence in 3G mobile systems, thus enabling ubiquitous sensing applications. We demonstrate these concepts and the principle operation in a sample ubiquitous Mobile Awareness service.

  10. United States Access Board

    MedlinePlus

    ... disabilities through leadership in accessible design and the development of accessibility guidelines and standards for the built environment, transportation, communication, medical diagnostic equipment, and information technology. ...

  11. Critical Access Hospitals (CAH)

    MedlinePlus

    ... use requirements for Critical Access Hospitals related to Electronic Health Records (EHRs)? Critical Access Hospital (CAH) are eligible for Electronic Health Record (EHR) incentive payments and can receive ...

  12. Mobile-IT Education (MIT.EDU): M-Learning Applications for Classroom Settings

    ERIC Educational Resources Information Center

    Sung, M.; Gips, J.; Eagle, N.; Madan, A.; Caneel, R.; DeVaul, R.; Bonsen, J.; Pentland, A.

    2005-01-01

    In this paper, we describe the Mobile-IT Education (MIT.EDU) system, which demonstrates the potential of using a distributed mobile device architecture for rapid prototyping of wireless mobile multi-user applications for use in classroom settings. MIT.EDU is a stable, accessible system that combines inexpensive, commodity hardware, a flexible…

  13. Investigating Students' Behavioural Intention to Adopt and Use Mobile Learning in Higher Education in East Africa

    ERIC Educational Resources Information Center

    Mtebe, Joel S.; Raisamo, Roope

    2014-01-01

    Recent penetration of mobile technologies and its services in East Africa has provided a new platform for institutions to widen access to education through mobile learning. Mobile technologies provide learners with flexibility and ubiquity to learn anytime and anywhere via wireless Internet. However, far too little research has been conducted to…

  14. Mobile Devices: Toys or Learning Tools for the 21st Century Teenagers?

    ERIC Educational Resources Information Center

    Kee, Ch'ng Lay; Samsudin, Zarina

    2014-01-01

    Learning is interwoven in daily life and so it can be take place at anytime and anywhere by using mobile device. In the 21st century, mobile devices have become ubiquitous, affordable and accessible for the teenagers. The teenagers have the opportunity to perform the learning activities by using the mobile devices. However, what are they used…

  15. Information Use and Barriers on a Mobile App in Distance Learning

    ERIC Educational Resources Information Center

    Du, Yunfei

    2015-01-01

    Mobile technologies such as iPhone apps make it possible for learners to freely access course content management systems, library Web sites, as well as reference services from anywhere, anytime. This paper reviewed the current status of mobile learning and suggested possible factors influencing the use of mobile apps in online learning. The author…

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

    NASA Technical Reports Server (NTRS)

    Castiel, David

    1991-01-01

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

  17. Choosing between responsive-design websites versus mobile apps for your mobile behavioral intervention: presenting four case studies.

    PubMed

    Turner-McGrievy, Gabrielle M; Hales, Sarah B; Schoffman, Danielle E; Valafar, Homay; Brazendale, Keith; Weaver, R Glenn; Beets, Michael W; Wirth, Michael D; Shivappa, Nitin; Mandes, Trisha; Hébert, James R; Wilcox, Sara; Hester, Andrew; McGrievy, Matthew J

    2016-11-03

    Both mobile apps and responsive-design websites (web apps) can be used to deliver mobile health (mHealth) interventions, but it can be difficult to discern which to use in research. The goal of this paper is to present four case studies from behavioral interventions that developed either a mobile app or a web app for research and present an information table to help researchers determine which mobile option would work best for them. Four behavioral intervention case studies (two developed a mobile app, and two developed a web app) presented include time, cost, and expertise. Considerations for adopting a mobile app or a web app-such as time, cost, access to programmers, data collection, security needs, and intervention components- are presented. Future studies will likely integrate both mobile app and web app modalities. The considerations presented here can help guide researchers on which platforms to choose prior to starting an mHealth intervention.

  18. WWW + smart card: towards a mobile health care management system.

    PubMed

    Chan, A T

    2000-07-01

    This paper highlights the benefits of combining the World Wide Web and smart card technologies to support a highly mobile health management framework. In particular, we describe an approach using the SmartCard-Web Gateway Interface (SGI) as a common interface to communicate and access the medical records residing in a smart card. Importantly, by employing HTTP as the baseline protocol to access information on the smart card, SGI promotes the use of de facto standard web browsers as the common client user interface. The initial implementation of the framework has demonstrated the feasibility of the concept in facilitating a truly mobile access of patient's medical records based on SGI.

  19. Protocol design for mobile radio group communications over satellite

    NASA Astrophysics Data System (ADS)

    Leung, Victor C. M.

    1992-10-01

    The protocol design for a mobile radio service supporting half-duplex push-to-talk voice communications over mobile satellite systems is presented. Two types of protocols are considered, namely, a demand assignment multiple access protocol to assign channels only to those user groups in active sessions of conversations and a signaling protocol to arbitrate contentions among members of the same user group within an assigned channel. It is concluded that the proposed access control protocol makes it possible to improve the throughput capacity of the assigned channel by 65 or 18 percent compared to manual carrier-sensed access without or with collisoin detection, respectively.

  20. Radioactive hot cell access hole decontamination machine

    DOEpatents

    Simpson, William E.

    1982-01-01

    Radioactive hot cell access hole decontamination machine. A mobile housing has an opening large enough to encircle the access hole and has a shielding door, with a door opening and closing mechanism, for uncovering and covering the opening. The housing contains a shaft which has an apparatus for rotating the shaft and a device for independently translating the shaft from the housing through the opening and access hole into the hot cell chamber. A properly sized cylindrical pig containing wire brushes and cloth or other disks, with an arrangement for releasably attaching it to the end of the shaft, circumferentially cleans the access hole wall of radioactive contamination and thereafter detaches from the shaft to fall into the hot cell chamber.

  1. A Theory of Access

    ERIC Educational Resources Information Center

    Ribot, Jesse C.; Peluso, Nancy Lee

    2003-01-01

    The term "access" is frequently used by property and natural resource analysts without adequate definition. In this paper we develop a concept of access and examine a broad set of factors that differentiate access from property. We define access as "the "ability" to derive benefits from things," broadening from property's classical definition as…

  2. Mobile robot knowledge base

    NASA Astrophysics Data System (ADS)

    Heath Pastore, Tracy; Barnes, Mitchell; Hallman, Rory

    2005-05-01

    Robot technology is developing at a rapid rate for both commercial and Department of Defense (DOD) applications. As a result, the task of managing both technology and experience information is growing. In the not-to-distant past, tracking development efforts of robot platforms, subsystems and components was not too difficult, expensive, or time consuming. To do the same today is a significant undertaking. The Mobile Robot Knowledge Base (MRKB) provides the robotics community with a web-accessible, centralized resource for sharing information, experience, and technology to more efficiently and effectively meet the needs of the robot system user. The resource includes searchable information on robot components, subsystems, mission payloads, platforms, and DOD robotics programs. In addition, the MRKB website provides a forum for technology and information transfer within the DOD robotics community and an interface for the Robotic Systems Pool (RSP). The RSP manages a collection of small teleoperated and semi-autonomous robotic platforms, available for loan to DOD and other qualified entities. The objective is to put robots in the hands of users and use the test data and fielding experience to improve robot systems.

  3. Mobile Router Technology Development

    NASA Technical Reports Server (NTRS)

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

    2002-01-01

    Cisco Systems and NASA have been performing joint research on mobile routing technology under a NASA Space Act Agreement. Cisco developed mobile router technology and provided that technology to NASA for applications to aeronautic and space-based missions. NASA has performed stringent performance testing of the mobile router, including the interaction of routing and transport-level protocols. This paper describes mobile routing, the mobile router, and some key configuration parameters. In addition, the paper describes the mobile routing test network and test results documenting the performance of transport protocols in dynamic routing environments.

  4. Mobility- Aware Cache Management in Wireless Environment

    NASA Astrophysics Data System (ADS)

    Kaur, Gagandeep; Saini, J. S.

    2010-11-01

    In infrastructure wireless environments, a base station provides communication links between mobile client and remote servers. Placing a proxy cache at the base station is an effective way of managing the wireless Internet bandwidth efficiently. However, in the situation of non-uniform heavy traffic, requests of all the mobile clients in the service area of the base station may cause overload in the cache. If the proxy cache has to release some cache space for the new mobile client in the environment, overload occurs. In this paper, we propose a novel cache management strategy to decrease the penalty of overloaded traffic on the proxy and to reduce the number of remote accesses by increasing the cache hit ratio. We predict the number of overload ahead of time based on its history and adapt the cache for the heavy traffic to be able to provide continuous and fair service to the current mobile clients and incoming ones. We have tested the algorithms over a real implementation of the cache management system in presence of fault tolerance and security. In our cache replacement algorithm, mobility of the clients, predicted overload number, size of the cached packets and their access frequencies are considered altogether. Performance results show that our cache management strategy outperforms the existing policies with less number of overloads and higher cache hit ratio.

  5. Mobile assistive technologies for the visually impaired.

    PubMed

    Hakobyan, Lilit; Lumsden, Jo; O'Sullivan, Dympna; Bartlett, Hannah

    2013-01-01

    There are around 285 million visually impaired people worldwide, and around 370,000 people are registered as blind or partially sighted in the UK. Ongoing advances in information technology (IT) are increasing the scope for IT-based mobile assistive technologies to facilitate the independence, safety, and improved quality of life of the visually impaired. Research is being directed at making mobile phones and other handheld devices accessible via our haptic (touch) and audio sensory channels. We review research and innovation within the field of mobile assistive technology for the visually impaired and, in so doing, highlight the need for successful collaboration between clinical expertise, computer science, and domain users to realize fully the potential benefits of such technologies. We initially reflect on research that has been conducted to make mobile phones more accessible to people with vision loss. We then discuss innovative assistive applications designed for the visually impaired that are either delivered via mainstream devices and can be used while in motion (e.g., mobile phones) or are embedded within an environment that may be in motion (e.g., public transport) or within which the user may be in motion (e.g., smart homes).

  6. Does Mobility Have to Mean Being Hard to Reach? Mobile Pastoralists and Education's "Terms of Inclusion"

    ERIC Educational Resources Information Center

    Dyer, Caroline

    2013-01-01

    Nomadic groups are highly discriminated against in access to education services, and the 2010 Education For All Global Monitoring Report demanded urgent action to address their education deprivation. Mobile pastoralists, particularly, appear to be falling beyond the remit of migration studies in education, although they are among the most mobile…

  7. Obstacle Characterization in a Geocrowdsourced Accessibility System

    NASA Astrophysics Data System (ADS)

    Qin, H.; Aburizaiza, A. O.; Rice, R. M.; Paez, F.; Rice, M. T.

    2015-08-01

    Transitory obstacles - random, short-lived and unpredictable objects - are difficult to capture in any traditional mapping system, yet they have significant negative impacts on the accessibility of mobility- and visually-impaired individuals. These transitory obstacles include sidewalk obstructions, construction detours, and poor surface conditions. To identify these obstacles and assist the navigation of mobility- and visually- impaired individuals, crowdsourced mapping applications have been developed to harvest and analyze the volunteered obstacles reports from local students, faculty, staff, and residents. In this paper, we introduce a training program designed and implemented for recruiting and motivating contributors to participate in our geocrowdsourced accessibility system, and explore the quality of geocrowdsourced data with a comparative analysis methodology.

  8. [Public access defibrillation in the Sorrento Peninsula].

    PubMed

    Santomauro, Maurizio; Giordano, Raffaele; Poli, Vincenzo; Iaccarino, Vincenzo; Palagiano, Francesco; Matarazzo, Luigi; Langella, Giuseppina; Riganti, Carla; Vosa, Carlo

    2012-10-01

    Early cardiac defibrillation is the only effective therapy to stop ventricular fibrillation or pulseless ventricular tachycardia. It is still considered the gold standard for the treatment of ventricular tachycardia/fibrillation, and is the only intervention capable of improving survival in cardiac arrest survivors. Timing of intervention, however, is crucial because after only 10 min success rates are very low (0-2%). Unfortunately, adequate relief cannot always be provided within the necessary time. The purpose of the public access defibrillation project in Sorrento was to create fixed and mobile first aid with automated external defibrillators in combination with the local 118 emergency system. With the involvement of pharmacies, bathing establishments and schools, 31 equally distant sites for public access defibrillation were made available. This organization was supplemented by mobile units on the cars of the Municipal Police and Civil Protection, and on patrol boats in the harbor.

  9. Internet Access to Spacecraft

    NASA Technical Reports Server (NTRS)

    Rash, James; Parise, Ron; Hogie, Keith; Criscuolo, Ed; Langston, Jim; Jackson, Chris; Price, Harold; Powers, Edward I. (Technical Monitor)

    2000-01-01

    The Operating Missions as Nodes on the Internet (OMNI) project at NASA's Goddard Space flight Center (GSFC), is demonstrating the use of standard Internet protocols for spacecraft communication systems. This year, demonstrations of Internet access to a flying spacecraft have been performed with the UoSAT-12 spacecraft owned and operated by Surrey Satellite Technology Ltd. (SSTL). Previously, demonstrations were performed using a ground satellite simulator and NASA's Tracking and Data Relay Satellite System (TDRSS). These activities are part of NASA's Space Operations Management Office (SOMO) Technology Program, The work is focused on defining the communication architecture for future NASA missions to support both NASA's "faster, better, cheaper" concept and to enable new types of collaborative science. The use of standard Internet communication technology for spacecraft simplifies design, supports initial integration and test across an IP based network, and enables direct communication between scientists and instruments as well as between different spacecraft, The most recent demonstrations consisted of uploading an Internet Protocol (IP) software stack to the UoSAT- 12 spacecraft, simple modifications to the SSTL ground station, and a series of tests to measure performance of various Internet applications. The spacecraft was reconfigured on orbit at very low cost. The total period between concept and the first tests was only 3 months. The tests included basic network connectivity (PING), automated clock synchronization (NTP), and reliable file transfers (FTP). Future tests are planned to include additional protocols such as Mobile IP, e-mail, and virtual private networks (VPN) to enable automated, operational spacecraft communication networks. The work performed and results of the initial phase of tests are summarized in this paper. This work is funded and directed by NASA/GSFC with technical leadership by CSC in arrangement with SSTL, and Vytek Wireless.

  10. Tandem mobile robot system

    DOEpatents

    Buttz, James H.; Shirey, David L.; Hayward, David R.

    2003-01-01

    A robotic vehicle system for terrain navigation mobility provides a way to climb stairs, cross crevices, and navigate across difficult terrain by coupling two or more mobile robots with a coupling device and controlling the robots cooperatively in tandem.

  11. Ion mobility sensor system

    DOEpatents

    Xu, Jun; Watson, David B.; Whitten, William B.

    2013-01-22

    An ion mobility sensor system including an ion mobility spectrometer and a differential mobility spectrometer coupled to the ion mobility spectrometer. The ion mobility spectrometer has a first chamber having first end and a second end extending along a first direction, and a first electrode system that generates a constant electric field parallel to the first direction. The differential mobility spectrometer includes a second chamber having a third end and a fourth end configured such that a fluid may flow in a second direction from the third end to the fourth end, and a second electrode system that generates an asymmetric electric field within an interior of the second chamber. Additionally, the ion mobility spectrometer and the differential mobility spectrometer form an interface region. Also, the first end and the third end are positioned facing one another so that the constant electric field enters the third end and overlaps the fluid flowing in the second direction.

  12. ECG by mobile technologies.

    PubMed

    Guzik, Przemyslaw; Malik, Marek

    Mobile electrocardiographs consist of three components: a mobile device (e.g. a smartphone), an electrocardiographic device or accessory, and a mobile application. Mobile platforms are small computers with sufficient computational power, good quality display, suitable data storage, and several possibilities of data transmission. Electrocardiographic electrodes and sensors for mobile use utilize unconventional materials, e.g. rubber, e-textile, and inkjet-printed nanoparticle electrodes. Mobile devices can be handheld, worn as vests or T-shirts, or attached to patient's skin as biopatches. Mobile electrocardiographic devices and accessories may additionally record other signals including respiratory rate, activity level, and geolocation. Large-scale clinical studies that utilize electrocardiography are easier to conduct using mobile technologies and the collected data are suitable for "big data" processing. This is expected to reveal phenomena so far inaccessible by standard electrocardiographic techniques.

  13. Quantitative imaging with a mobile phone microscope.

    PubMed

    Skandarajah, Arunan; Reber, Clay D; Switz, Neil A; Fletcher, Daniel A

    2014-01-01

    Use of optical imaging for medical and scientific applications requires accurate quantification of features such as object size, color, and brightness. High pixel density cameras available on modern mobile phones have made photography simple and convenient for consumer applications; however, the camera hardware and software that enables this simplicity can present a barrier to accurate quantification of image data. This issue is exacerbated by automated settings, proprietary image processing algorithms, rapid phone evolution, and the diversity of manufacturers. If mobile phone cameras are to live up to their potential to increase access to healthcare in low-resource settings, limitations of mobile phone-based imaging must be fully understood and addressed with procedures that minimize their effects on image quantification. Here we focus on microscopic optical imaging using a custom mobile phone microscope that is compatible with phones from multiple manufacturers. We demonstrate that quantitative microscopy with micron-scale spatial resolution can be carried out with multiple phones and that image linearity, distortion, and color can be corrected as needed. Using all versions of the iPhone and a selection of Android phones released between 2007 and 2012, we show that phones with greater than 5 MP are capable of nearly diffraction-limited resolution over a broad range of magnifications, including those relevant for single cell imaging. We find that automatic focus, exposure, and color gain standard on mobile phones can degrade image resolution and reduce accuracy of color capture if uncorrected, and we devise procedures to avoid these barriers to quantitative imaging. By accommodating the differences between mobile phone cameras and the scientific cameras, mobile phone microscopes can be reliably used to increase access to quantitative imaging for a variety of medical and scientific applications.

  14. Quantitative Imaging with a Mobile Phone Microscope

    PubMed Central

    Skandarajah, Arunan; Reber, Clay D.; Switz, Neil A.; Fletcher, Daniel A.

    2014-01-01

    Use of optical imaging for medical and scientific applications requires accurate quantification of features such as object size, color, and brightness. High pixel density cameras available on modern mobile phones have made photography simple and convenient for consumer applications; however, the camera hardware and software that enables this simplicity can present a barrier to accurate quantification of image data. This issue is exacerbated by automated settings, proprietary image processing algorithms, rapid phone evolution, and the diversity of manufacturers. If mobile phone cameras are to live up to their potential to increase access to healthcare in low-resource settings, limitations of mobile phone–based imaging must be fully understood and addressed with procedures that minimize their effects on image quantification. Here we focus on microscopic optical imaging using a custom mobile phone microscope that is compatible with phones from multiple manufacturers. We demonstrate that quantitative microscopy with micron-scale spatial resolution can be carried out with multiple phones and that image linearity, distortion, and color can be corrected as needed. Using all versions of the iPhone and a selection of Android phones released between 2007 and 2012, we show that phones with greater than 5 MP are capable of nearly diffraction-limited resolution over a broad range of magnifications, including those relevant for single cell imaging. We find that automatic focus, exposure, and color gain standard on mobile phones can degrade image resolution and reduce accuracy of color capture if uncorrected, and we devise procedures to avoid these barriers to quantitative imaging. By accommodating the differences between mobile phone cameras and the scientific cameras, mobile phone microscopes can be reliably used to increase access to quantitative imaging for a variety of medical and scientific applications. PMID:24824072

  15. World Wide Access: Accessible Web Design.

    ERIC Educational Resources Information Center

    Washington Univ., Seattle.

    This brief paper considers the application of "universal design" principles to Web page design in order to increase accessibility for people with disabilities. Suggestions are based on the World Wide Web Consortium's accessibility initiative, which has proposed guidelines for all Web authors and federal government standards. Seven guidelines for…

  16. Access Nets: Modeling Access to Physical Spaces

    NASA Astrophysics Data System (ADS)

    Frohardt, Robert; Chang, Bor-Yuh Evan; Sankaranarayanan, Sriram

    Electronic, software-managed mechanisms using, for example, radio-frequency identification (RFID) cards, enable great flexibility in specifying access control policies to physical spaces. For example, access rights may vary based on time of day or could differ in normal versus emergency situations. With such fine-grained control, understanding and reasoning about what a policy permits becomes surprisingly difficult requiring knowledge of permission levels, spatial layout, and time. In this paper, we present a formal modeling framework, called AccessNets, suitable for describing a combination of access permissions, physical spaces, and temporal constraints. Furthermore, we provide evidence that model checking techniques are effective in reasoning about physical access control policies. We describe our results from a tool that uses reachability analysis to validate security policies.

  17. A retransmission protocol for the message service of a land mobile satellite experiment

    NASA Technical Reports Server (NTRS)

    Yan, T.-Y.; Li, V. O. K.

    1985-01-01

    The objectives of NASA's land mobile satellite experiments are discussed. The assigned multiple access protocol combined with a retransmission scheme is to provide reliable transmission of data messages from mobiles to base stations (BSs). The sequences for communication between mobiles and BSs, mobiles and the network management center (NMC), and BSs and NMC are examined, and an example of mobiles/BSs communication is provided. The performance of the retransmission protocol and data message reservation and message channels delays are analyzed. A bit error rate of 0.001 is observed for satellite channels in a mobile environment and the message error probability is between 0-0.1.

  18. Mobility and Young Children.

    ERIC Educational Resources Information Center

    Bernard van Leer Foundation Newsletter, 1994

    1994-01-01

    This newsletter theme issue deals with the phenomenon of mobility or transience in India, Kenya, Greece, Ireland, Malaysia, Thailand and Israel. The primary focus is on mobility's effect on young children, specifically their health and education; some of the broader concerns also addressed by the newsletter are the causes of mobility and its…

  19. Mobile Student Information System

    ERIC Educational Resources Information Center

    Asif, Muhammad; Krogstie, John

    2011-01-01

    Purpose: A mobile student information system (MSIS) based on mobile computing and context-aware application concepts can provide more user-centric information services to students. The purpose of this paper is to describe a system for providing relevant information to students on a mobile platform. Design/methodology/approach: The research…

  20. Sustainable mobile information infrastructures in low resource settings.

    PubMed

    Braa, Kristin; Purkayastha, Saptarshi

    2010-01-01

    Developing countries represent the fastest growing mobile markets in the world. For people with no computing access, a mobile will be their first computing device. Mobile technologies offer a significant potential to strengthen health systems in developing countries with respect to community based monitoring, reporting, feedback to service providers, and strengthening communication and coordination between different health functionaries, medical officers and the community. However, there are various challenges in realizing this potential including technological such as lack of power, social, institutional and use issues. In this paper a case study from India on mobile health implementation and use will be reported. An underlying principle guiding this paper is to see mobile technology not as a "stand alone device" but potentially an integral component of an integrated mobile supported health information infrastructure.

  1. Cordless telephone use: implications for mobile phone research.

    PubMed

    Redmayne, Mary; Inyang, Imo; Dimitriadis, Christina; Benke, Geza; Abramson, Michael J

    2010-04-01

    Cordless and mobile (cellular) telephone use has increased substantially in recent years causing concerns about possible health effects. This has led to much epidemiological research, but the usual focus is on mobile telephone radiofrequency (RF) exposure only despite cordless RF being very similar. Access to and use of cordless phones were included in the Mobile Radiofrequency Phone Exposed Users Study (MoRPhEUS) of 317 Year 7 students recruited from Melbourne, Australia. Participants completed an exposure questionnaire-87% had a cordless phone at home and 77% owned a mobile phone. There was a statistically significant positive relationship (r = 0.38, p < 0.01) between cordless and mobile phone use. Taken together, this increases total RF exposure and its ratio in high-to-low mobile users. Therefore, the design and analysis of future epidemiological telecommunication studies need to assess cordless phone exposure to accurately evaluate total RF telephone exposure effects.

  2. 36 CFR 1192.23 - Mobility aid accessibility.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ...) Platform surface. The platform surface shall be free of any protrusions over 1/4 inch high and shall be... inches, and the transition from roadway or sidewalk to ramp may be vertical without edge treatment up to...) Ramp threshold. The transition from roadway or sidewalk and the transition from vehicle floor to...

  3. 49 CFR 38.23 - Mobility aid accessibility.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... supplementary system is engaged. (6) Platform surface. The platform surface shall be free of any protrusions..., for a maximum rise of 3 inches, and the transition from roadway or sidewalk to ramp may be vertical.... (3) Ramp threshold. The transition from roadway or sidewalk and the transition from vehicle floor...

  4. 36 CFR 1192.159 - Mobility aid accessibility.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... lifts, ramps or bridge plates meeting the applicable requirements of this section are provided at... the platform. The handrails shall be capable of withstanding a force of 100 pounds (445 N... inches (760 mm) above the ramp surface. The handrails shall be capable of withstanding a force of...

  5. 49 CFR 38.159 - Mobility aid accessibility.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ...) Exception. If portable or station-based lifts, ramps or bridge plates meeting the applicable requirements of... the platform. The handrails shall be capable of withstanding a force of 100 pounds (445 N... inches (760 mm) above the ramp surface. The handrails shall be capable of withstanding a force of...

  6. 49 CFR 38.83 - Mobility aid accessibility.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... maneuverability when entering or leaving the vehicle. (c) Vehicle ramp or bridge plate—(1) Design load. Ramps or bridge plates 30 inches or longer shall support a load of 600 pounds, placed at the centroid of the ramp... load of 300 pounds. (2) Ramp surface. The ramp or bridge plate surface shall be continuous and...

  7. 36 CFR 1192.83 - Mobility aid accessibility.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... maneuverability when entering or leaving the vehicle. (c) Vehicle ramp or bridge plate—(1) Design load. Ramps or bridge plates 30 inches or longer shall support a load of 600 pounds, placed at the centroid of the ramp... shall support a load of 300 pounds. (2) Ramp surface. The ramp or bridge plate surface shall...

  8. 49 CFR 38.125 - Mobility aid accessibility.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... car. (c) Car ramp or bridge plate—(1) Design load. Ramps or bridge plates 30 inches or longer shall support a load of 600 pounds, placed at the centroid of the ramp or bridge plate distributed over an area... material. Ramps or bridge plates shorter than 30 inches shall support a load of 300 pounds. (2)...

  9. 49 CFR 38.95 - Mobility aid accessibility.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ...) Design load. Ramps or bridge plates 30 inches or longer shall support a load of 600 pounds, placed at the... 30 inches shall support a load of 300 pounds. (2) Ramp surface. The ramp or bridge plate surface... or boarding device (e.g., lift, ramp or bridge plate) complying with either paragraph (b) or (c)...

  10. 49 CFR 38.83 - Mobility aid accessibility.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... maneuverability when entering or leaving the vehicle. (c) Vehicle ramp or bridge plate—(1) Design load. Ramps or bridge plates 30 inches or longer shall support a load of 600 pounds, placed at the centroid of the ramp... load of 300 pounds. (2) Ramp surface. The ramp or bridge plate surface shall be continuous and...

  11. 36 CFR 1192.159 - Mobility aid accessibility.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... lifts, ramps or bridge plates meeting the applicable requirements of this section are provided at... load. The design load of the lift shall be at least 600 pounds (2665 N). Working parts, such as cables... load, shall have a safety factor of at least six, based on the ultimate strength of the...

  12. 36 CFR 1192.159 - Mobility aid accessibility.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... lifts, ramps or bridge plates meeting the applicable requirements of this section are provided at... load. The design load of the lift shall be at least 600 pounds (2665 N). Working parts, such as cables... load, shall have a safety factor of at least six, based on the ultimate strength of the...

  13. 36 CFR 1192.83 - Mobility aid accessibility.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... maneuverability when entering or leaving the vehicle. (c) Vehicle ramp or bridge plate—(1) Design load. Ramps or bridge plates 30 inches or longer shall support a load of 600 pounds, placed at the centroid of the ramp... shall support a load of 300 pounds. (2) Ramp surface. The ramp or bridge plate surface shall...

  14. 49 CFR 38.95 - Mobility aid accessibility.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... car. (c) Car ramp or bridge plate—(1) Design load. Ramps or bridge plates 30 inches or longer shall support a load of 600 pounds, placed at the centroid of the ramp or bridge plate distributed over an area... material. Ramps or bridge plates shorter than 30 inches shall support a load of 300 pounds. (2)...

  15. 49 CFR 38.125 - Mobility aid accessibility.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ...) Requirements. The controls shall be interlocked with the car brakes, propulsion system, or door, or shall... propulsion system interlocks requirement does not apply to platform mounted or portable lifts provided that a mechanical, electrical or other system operates to ensure that cars do not move when the lift is in use....

  16. 36 CFR 1192.83 - Mobility aid accessibility.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... the vehicle brakes, propulsion system, or door, or shall provide other appropriate mechanisms or...) Exception. The brake or propulsion system interlocks requirement does not apply to a station platform mounted lift provided that a mechanical, electrical or other system operates to ensure that vehicles...

  17. 36 CFR 1192.125 - Mobility aid accessibility.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... be interlocked with the car brakes, propulsion system, or door, or shall provide other appropriate... is intended to be stowed while occupied. (iii) Exception. The brake or propulsion system interlocks requirement does not apply to platform mounted or portable lifts provided that a mechanical, electrical...

  18. 49 CFR 38.95 - Mobility aid accessibility.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ...) Controls—(i) Requirements. The controls shall be interlocked with the car brakes, propulsion system, or.... (iii) Exception. The brake or propulsion system interlock requirement does not apply to a platform mounted or portable lift provided that a mechanical, electrical or other system operates to ensure...

  19. 49 CFR 38.83 - Mobility aid accessibility.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... the vehicle brakes, propulsion system, or door, or shall provide other appropriate mechanisms or...) Exception. The brake or propulsion system interlocks requirement does not apply to a station platform mounted lift provided that a mechanical, electrical or other system operates to ensure that vehicles...

  20. 36 CFR 1192.95 - Mobility aid accessibility.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ...) Requirements. The controls shall be interlocked with the car brakes, propulsion system, or door, or shall... propulsion system interlock requirement does not apply to a platform mounted or portable lift provided that a mechanical, electrical or other system operates to ensure that cars do not move when the lift is in use....

  1. 49 CFR 38.83 - Mobility aid accessibility.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... the vehicle brakes, propulsion system, or door, or shall provide other appropriate mechanisms or..., each control for deploying, lowering, raising, and stowing the lift and lowering the roll-off barrier...) Exception. The brake or propulsion system interlocks requirement does not apply to a station...

  2. 49 CFR 38.159 - Mobility aid accessibility.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... brakes, transmission, or door, or shall provide other appropriate mechanisms or systems, to ensure that..., lowering, raising, and stowing the lift and lowering the roll-off barrier shall be of a momentary contact...) Platform barriers. The lift platform shall be equipped with barriers to prevent any of the wheels of...

  3. 49 CFR 38.125 - Mobility aid accessibility.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... be interlocked with the car brakes, propulsion system, or door, or shall provide other appropriate..., lowering, raising, and stowing the lift and lowering the roll-off barrier shall be of a monetary contact... is intended to be stowed while occupied. (iii) Exception. The brake or propulsion system...

  4. 49 CFR 38.95 - Mobility aid accessibility.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ...) Requirements. The controls shall be interlocked with the car brakes, propulsion system, or door, or shall..., each control for deploying, lowering, raising, and stowing the lift and lowering the roll-off barrier... passenger compartment and the lift is intended to be stowed while occupied. (iii) Exception. The brake...

  5. 49 CFR 38.23 - Mobility aid accessibility.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ...) Requirements. The controls shall be interlocked with the vehicle brakes, transmission, or door, or shall... stowing the lift and lowering the roll-off barrier shall be of a momentary contact type requiring... occupant in the event of a single failure of any load carrying component. (5) Platform barriers. The...

  6. 49 CFR 38.23 - Mobility aid accessibility.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ..., such as platform, frame, and attachment hardware which would not be expected to wear, shall have a... stowing the lift and lowering the roll-off barrier shall be of a momentary contact type requiring... supporting structure. The handrail shall have a cross-sectional diameter between 11/4 inches and 11/2...

  7. 36 CFR 1192.23 - Mobility aid accessibility.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... on the ultimate strength of the material. Nonworking parts, such as platform, frame, and attachment... shall be of a momentary contact type requiring continuous manual pressure by the operator and shall not... concentrated at any point on the handrail without permanent deformation of the rail or its supporting...

  8. 36 CFR 1192.23 - Mobility aid accessibility.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... on the ultimate strength of the material. Nonworking parts, such as platform, frame, and attachment... shall be of a momentary contact type requiring continuous manual pressure by the operator and shall not... concentrated at any point on the handrail without permanent deformation of the rail or its supporting...

  9. 49 CFR 38.95 - Mobility aid accessibility.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... material. Nonworking parts, such as platform, frame, and attachment hardware which would not be expected to... roll-off barrier shall be of a monetary contact type requiring continuous manual pressure by the... prohibiting the lift from being stowed while occupied shall not apply to a lift design of this type if...

  10. 49 CFR 38.83 - Mobility aid accessibility.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... on the ultimate strength of the material. Nonworking parts, such as platform, frame, and attachment... shall be of a momentary contact type requiring continuous manual pressure by the operator and shall not... lift from being stowed while occupied shall not apply to a lift design of this type if the...

  11. 36 CFR 1192.125 - Mobility aid accessibility.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... least six, based on the ultimate strength of the material. Nonworking parts, such as platform, frame... type requiring continuous manual pressure by the operator and shall not allow improper lift sequencing... a lift design of this type if the stowed position is within the passenger compartment and the...

  12. 36 CFR 1192.95 - Mobility aid accessibility.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... parts, such as platform, frame, and attachment hardware which would not be expected to wear, shall have... shall be of a momentary contact type requiring continuous manual pressure by the operator and shall not... stowed while occupied shall not apply to a lift design of this type if the stowed position is within...

  13. 36 CFR 1192.83 - Mobility aid accessibility.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... on the ultimate strength of the material. Nonworking parts, such as platform, frame, and attachment... shall be of a momentary contact type requiring continuous manual pressure by the operator and shall not... lift from being stowed while occupied shall not apply to a lift design of this type if the...

  14. 36 CFR 1192.83 - Mobility aid accessibility.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... on the ultimate strength of the material. Nonworking parts, such as platform, frame, and attachment... shall be of a momentary contact type requiring continuous manual pressure by the operator and shall not... lift from being stowed while occupied shall not apply to a lift design of this type if the...

  15. 49 CFR 38.159 - Mobility aid accessibility.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... ultimate strength of the material. Nonworking parts, such as platform, frame and attachment hardware which... type requiring continuous manual pressure by the operator and shall not allow improper lift sequencing...) concentrated at any point on the handrail without permanent deformation of the rail or its supporting...

  16. 36 CFR 1192.159 - Mobility aid accessibility.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    .... Nonworking parts, such as platform, frame and attachment hardware which would not be expected to wear, shall... stowing the lift and lowering the roll-off barrier shall be of a momentary contact type requiring...) concentrated at any point on the handrail without permanent deformation of the rail or its supporting...

  17. 36 CFR 1192.125 - Mobility aid accessibility.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... least six, based on the ultimate strength of the material. Nonworking parts, such as platform, frame... type requiring continuous manual pressure by the operator and shall not allow improper lift sequencing... a lift design of this type if the stowed position is within the passenger compartment and the...

  18. 36 CFR 1192.159 - Mobility aid accessibility.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    .... Nonworking parts, such as platform, frame and attachment hardware which would not be expected to wear, shall... stowing the lift and lowering the roll-off barrier shall be of a momentary contact type requiring...) concentrated at any point on the handrail without permanent deformation of the rail or its supporting...

  19. 49 CFR 38.125 - Mobility aid accessibility.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    .... Nonworking parts, such as platform, frame, and attachment hardware which would not be expected to wear, shall... shall be of a monetary contact type requiring continuous manual pressure by the operator and shall not... stowed while occupied shall not apply to a lift design of this type if the stowed position is within...

  20. 36 CFR 1192.95 - Mobility aid accessibility.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... parts, such as platform, frame, and attachment hardware which would not be expected to wear, shall have... shall be of a momentary contact type requiring continuous manual pressure by the operator and shall not... stowed while occupied shall not apply to a lift design of this type if the stowed position is within...

  1. 36 CFR 1192.23 - Mobility aid accessibility.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... the centroid of the platform. (10) Platform movement. No part of the platform shall move at a rate... attached to the vehicle so that it is not subject to displacement when loading or unloading a heavy...

  2. Influence of the Laser Diode Nonlinearity in Fiber-Fed Microcellular Networks

    NASA Astrophysics Data System (ADS)

    Gameiro, A.

    In this paper, the use of an optical fiber-based fixed infrastructure for code division multiple access (CDMA) mobile networks is considered. One of the major problems associated with optical subcarrier multiplexing (SCM) is the nonlinearity of the laser diodes (LD). The LD is modeled by a memoryless nonlinearity, and the effect of the nonlinearity on the SCM transmission of CDMA signals is evaluated. The behavior departs significantly from what happens in frequency division multiple access (FDMA), and depends critically on the nonlinearity being compressing or expanding. In the former case, significant performance degradation may occur, whereas for the latter this is usually not dramatic. When compared against FDMA, the major advantage of CDMA comes from the tight power control function that must be built in such systems, which means that situations of a weak signal corrupted by strong signals do not occur, unlike what happens in FDMA.

  3. Mobile satellite services: The quest for spectrum

    NASA Astrophysics Data System (ADS)

    Hunt, Murray J.; Amero, Ronald G.

    The acquisition of suitable frequency spectrum at International Telecommunications Union (ITU) World Administrative Radio Conferences (WARCs) and access to it through international frequency coordination is vital to the success of commercial mobile satellite (MSAT) systems. Mobile satellite services were conceived in the late sixties as a means of providing reliable wide area communications to aircraft. Although this service did not come to fruition at that time, commercial maritime mobile satellite communications were inaugurated by Inmarsat some years later. The application in a domestic mobile satellite service context was extensively examined by the Department of Communications in the early eighties, which eventually led to the decision by Telesat Canada to assume responsibility for the project as a commercial venture and to the formation of Telesat Mobile Inc. (TMI). Each of these events is traced to the process of frequency allocation at WARCs. This paper also examines the complex international coordination activities related to MSAT. Finally, some preliminary thoughts are given on the importance of a future WARC component to deal with mobile satellite services, expected in the 1990s.

  4. Sustainable mobility in rural China.

    PubMed

    Dalkmann, Holger; Hutfilter, Sabine; Vogelpohl, Karin; Schnabel, Peter

    2008-04-01

    Rural areas in China suffer from various problems. The stagnating economic development and a lack of (sufficient) job opportunities and basic services, etc., lead to disadvantages for great parts of China's population. In this context, the transport sector plays a crucial role for the development of rural settlements. Although the degree of undersupply varies between villages, the situation of Chinese villages is often worsened by an insufficient developed transport sector. Regarding mobility in rural China, major constraints and therefore challenges are the difficult access to the transport infrastructure, bad road conditions and the lack of public transport systems. Improvements within the transport sector can be regarded as crucial for the economic and social development of (rural) China and should be carried out in a sustainable and holistic manner using participatory approaches. The aim should be the development of mobility strategies considering the specific needs within the field of transport, which shall have a decisive and positive impact on related sectors. This paper is based on experiences made during the 3 years lasting Sino-European research project SUCCESS (Sustainable Users Concept for China Engaging Scientific Scenario) that analyses the present and the potential future role of transport systems in selected rural areas of China. Referring to the case studies of three villages in rural China, some mobility-related projects that present a favourable impact not only on the transport sector but also on the social system and the economy shall be highlighted. Finally, based on the analysis, instruments and measures for the development of a pathway to a sustainable mobility in rural China will be outlined.

  5. System services and architecture of the TMI satellite mobile data system

    NASA Technical Reports Server (NTRS)

    Gokhale, D.; Agarwal, A.; Guibord, A.

    1993-01-01

    The North American Mobile Satellite Service (MSS) system being developed by AMSC/TMI and scheduled to go into service in early 1995 will include the provision for real time packet switched services (mobile data service - MDS) and circuit switched services (mobile telephony service - MTS). These services will utilize geostationary satellites which provide access to mobile terminals (MT's) through L-band beams. The MDS system utilizes a star topology with a centralized data hub (DH) and will support a large number of mobile terminals. The DH, which accesses the satellite via a single Ku band beam, is responsible for satellite resource management, for providing mobile users with access to public and private data networks, and for comprehensive network management of the system. This paper describes the various MDS services available for the users, the ground segment elements involved in the provisioning of these services, and a summary description of the channel types, protocol architecture, and network management capabilities provided within the system.

  6. Mobile Virtual Private Networking

    NASA Astrophysics Data System (ADS)

    Pulkkis, Göran; Grahn, Kaj; Mårtens, Mathias; Mattsson, Jonny

    Mobile Virtual Private Networking (VPN) solutions based on the Internet Security Protocol (IPSec), Transport Layer Security/Secure Socket Layer (SSL/TLS), Secure Shell (SSH), 3G/GPRS cellular networks, Mobile IP, and the presently experimental Host Identity Protocol (HIP) are described, compared and evaluated. Mobile VPN solutions based on HIP are recommended for future networking because of superior processing efficiency and network capacity demand features. Mobile VPN implementation issues associated with the IP protocol versions IPv4 and IPv6 are also evaluated. Mobile VPN implementation experiences are presented and discussed.

  7. Residential mobility microsimulation models

    NASA Astrophysics Data System (ADS)

    Wang, Yifei; Wu, Lun

    2010-09-01

    Residential mobility refers to the spatial movement of individuals and households between dwellings within an urban area. This considerable amount of intra-urban movement affects the urban structure and has significant repercussions for urban transportation. In order to understand and project related impacts, a considerable number of residential mobility models has been developed and used in the regional planning process. Within this context, the history and state-of-art residential mobility models are discussed and indicated. Meanwhile, a residential mobility Microsimulation model, called URM-Microsim (Urban Residential Mobility Microsimulation), is introduced and discussed.

  8. Ion mobility sensor

    DOEpatents

    Koo, Jackson C.; Yu, Conrad M.

    2005-08-23

    An ion mobility sensor which can detect both ion and molecules simultaneously. Thus, one can measure the relative arrival times between various ions and molecules. Different ions have different mobility in air, and the ion sensor enables measurement of ion mobility, from which one can identify the various ions and molecules. The ion mobility sensor which utilizes a pair of glow discharge devices may be designed for coupling with an existing gas chromatograph, where various gas molecules are already separated, but numbers of each kind of molecules are relatively small, and in such cases a conventional ion mobility sensor cannot be utilized.

  9. Mobile Sensor Technologies Being Developed

    NASA Technical Reports Server (NTRS)

    Greer, Lawrence C.; Oberle, Lawrence G.

    2003-01-01

    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 equipment to miniaturize an existing sensor platform. We developed a five-circuit-board suite, with an average board size of 1.5 by 3 cm. Shown in the preceding photograph, this suite provides all motor control, direction finding, and communications capabilities for a 27- by 21- by 40-mm prototype mobile platform. The second part of the project is to provide communications between mobile platforms, and also between multiple platforms and a central command location. This is accomplished with a low-power network labeled "SPAN," Sensor Platform Area Network, a local area network made up of proximity elements. In practice, these proximity elements are composed of fixed- and mobile-sensor-laden science packages that communicate to each other via radiofrequency links. Data in the network will be shared by a central command location that will pass information into and out of the network through its access to a backbone element. The result will be a protocol portable to general purpose microcontrollers satisfying a host of sensor networking tasks. This network will enter the gap somewhere between television remotes and Bluetooth but, unlike 802.15.4, will not specify a physical layer, thus allowing for many data rates over optical, acoustical, radiofrequency, hardwire, or other media. Since the protocol will exist as portable C-code, developers may be able to embed it in a host of microcontrollers from commercial to space grade and, of course, to design it into ASICs. Unlike in 802.15.4, the nodes will relate to each other as peers. A demonstration of this protocol using the two test bed platforms was recently held. Two NASA modified, commercially available, mobile platforms communicated and shared data with each other and a

  10. Primary vascular access.

    PubMed

    Gibbons, C P

    2006-05-01

    Primary vascular access is usually achievable by a distal autogenous arterio-venous fistula (AVF). This article describes the approach to vascular access planning, the usual surgical options and the factors affecting patency.

  11. Perspectives of a mobile application for people with communication disabilities in the community.

    PubMed

    Crook, Alice; Kenny, Julie; Johnson, Hilary; Davidson, Bronwyn

    2017-02-01

    Purpose To determine the perceptions of people with complex communication needs (CCN) and business staff regarding the uses and functionality of a mobile application to aid communication access. Method A qualitative study using thematic analysis of transcripts and field notes from focus groups and interviews of 19 people with CCN and nine business staff. Results Four themes and 10 subthemes were drawn from the data. Themes highlighted the desire for: increased communication strategies to support customer interactions, increased access to information, functionality of a mobile application to increase its utility, and preferred technical and visual features of mobile applications. Conclusion People with CCN and business staff perceived a mobile application as a useful tool to aid communication access. This research highlighted the importance of facilitating strategies to communicative interactions and information in the community as the fundamental goal of a mobile application developed to support communication access. Implications for Rehabilitation Mobile applications are widely accepted and used in modern customer service industries and have been identified as tools to increase communication access for people with complex communication needs (CCN). People with CCN identified accessibility, presentation, and customisation as important features of mobile applications for communication access. The diversity of user preferences and needs, and the rapid development of new technologies limit the applicability of a single design for mobile applications for people with CCN. People with CCN should be involved in application design and development. A mobile application for communication access would support customer-business interactions as well as enable more accessible information sharing about disability needs and services.

  12. [Accessible Rural Housing.

    ERIC Educational Resources Information Center

    Baker, Nick, Ed.

    1995-01-01

    This issue of the quarterly newsletter "Rural Exchange" provides information and resources on accessible rural housing for the disabled. "Accessible Manufactured Housing Could Increase Rural Home Supply" (Nick Baker) suggests that incorporation of access features such as lever door handles and no-step entries into manufactured housing could help…

  13. Reflective Database Access Control

    ERIC Educational Resources Information Center

    Olson, Lars E.

    2009-01-01

    "Reflective Database Access Control" (RDBAC) is a model in which a database privilege is expressed as a database query itself, rather than as a static privilege contained in an access control list. RDBAC aids the management of database access controls by improving the expressiveness of policies. However, such policies introduce new interactions…

  14. Open Access Alternatives

    ERIC Educational Resources Information Center

    Tenopir, Carol

    2004-01-01

    Open access publishing is a hot topic today. But open access publishing can have many different definitions, and pros and cons vary with the definitions. Open access publishing is especially attractive to companies and small colleges or universities that are likely to have many more readers than authors. A downside is that a membership fee sounds…

  15. Demystifying Remote Access

    ERIC Educational Resources Information Center

    Howe, Grant

    2009-01-01

    With money tight, more and more districts are considering remote access as a way to reduce expenses and budget information technology costs more effectively. Remote access allows staff members to work with a hosted software application from any school campus without being tied to a specific physical location. Each school can access critical…

  16. Improving Mobile Infrastructure for Pervasive Personal Computing

    DTIC Science & Technology

    2007-11-01

    ISR model of mobile computing, users take advantage of pervasive de- ployments of inexpensive, mass-market PC hardware rather than carrying portable ...carry one’s computing environment in a portable computer. Instead, an exact replica of the last checkpointed state of a user’s entire computing...restricted. The same assumption applies to a portable computer that is physically safeguarded by the user at all times. In contrast, physical access to

  17. Globalstar communications payload for global mobile communications

    NASA Astrophysics Data System (ADS)

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

    1992-03-01

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

  18. Mobile Phone Application Development for the Classroom

    NASA Astrophysics Data System (ADS)

    Lewis, P.; Oostra, D.; Crecelius, S.; Chambers, L. H.

    2012-08-01

    With smartphone sales currently surpassing laptop sales, it is hard not to think that these devices will have a place in the classroom. More specifically, with little to no monetary investment, classroom-centric mobile applications have the ability to suit the needs of teachers. Previously, programming such an item was a daunting task to the classroom teacher. But now, through the use of online visual tools, anyone has the ability to generate a mobile application to suit individual classroom needs. The "MY NASA DATA" (MND) project has begun work on such an application. Using online tools that are directed at the non-programmer, the team has developed two usable mobile applications ("apps") that fit right into the science classroom. The two apps generated include a cloud dichotomous key for cloud identification in the field, and an atmospheric science glossary to help with standardized testing key vocabulary and classroom assignments. Through the use of free online tools, teachers and students now have the ability to customize mobile applications to meet their individual needs. As an extension of the mobile applications, the MND team is planning web-based application programming interfaces (API's) that will be generated from data that is currently included in the MND Live Access Server. This will allow teachers and students to choose data sets that they want to include in the mobile application without having to populate the API themselves. Through the use of easy to understand online mobile app tutorials and MND data sets, teachers will have the ability to generate unit-specific mobile applications to further engage and empower students in the science classroom.

  19. Pubcast and Genecast: Browsing and explor-ing publications and associated curated con-tent in biology through mobile devices.

    PubMed

    Goldweber, Scott; Theodore, Jamal; John Torcivia-Rodriguez, John; Simonyan, Vahan; Mazumder, Raja

    2016-03-23

    Services such as Facebook, Amazon, and eBay were once solely accessed from stationary computers. These web services are now being used increasingly on mobile devices. We acknowledge this new reality by providing users a way to access publications and a curated cancer mutation database on their mobile device with daily automated updates.

  20. Tracking Human Mobility Using WiFi Signals

    PubMed Central

    Sapiezynski, Piotr; Stopczynski, Arkadiusz; Gatej, Radu; Lehmann, Sune

    2015-01-01

    We study six months of human mobility data, including WiFi and GPS traces recorded with high temporal resolution, and find that time series of WiFi scans contain a strong latent location signal. In fact, due to inherent stability and low entropy of human mobility, it is possible to assign location to WiFi access points based on a very small number of GPS samples and then use these access points as location beacons. Using just one GPS observation per day per person allows us to estimate the location of, and subsequently use, WiFi access points to account for 80% of mobility across a population. These results reveal a great opportunity for using ubiquitous WiFi routers for high-resolution outdoor positioning, but also significant privacy implications of such side-channel location tracking. PMID:26132115

  1. [The NAS system: Nursing Activities Score in mobile technology].

    PubMed

    Catalan, Vanessa Menezes; Silveira, Denise Tolfo; Neutzling, Agnes Ludwig; Martinato, Luísa Helena Machado; Borges, Gilberto Cabral de Mello

    2011-12-01

    The objective of this study was to present the computerized structure that enables the use of the Nursing Activities Score (NAS) in mobile technology. It is a project for the development of technology production based on software engineering, founded on the theory of systems development life cycle. The NAS system was built in two modules: the search module, which is accessed using a personal computer (PC), and Data Collection module, which is accessed through a mobile device (Smartphone). The NAS system was constructed to allow other forms, in addition to the NAS tool, to be included in the future. Thus, it is understood that the development of the NAS will bring nurses closer to mobile technology and facilitate their accessibility to the data of the instrument relating to patients, thus assisting in decision-making and in staffing to provide nursing care.

  2. Tracking Human Mobility Using WiFi Signals.

    PubMed

    Sapiezynski, Piotr; Stopczynski, Arkadiusz; Gatej, Radu; Lehmann, Sune

    2015-01-01

    We study six months of human mobility data, including WiFi and GPS traces recorded with high temporal resolution, and find that time series of WiFi scans contain a strong latent location signal. In fact, due to inherent stability and low entropy of human mobility, it is possible to assign location to WiFi access points based on a very small number of GPS samples and then use these access points as location beacons. Using just one GPS observation per day per person allows us to estimate the location of, and subsequently use, WiFi access points to account for 80% of mobility across a population. These results reveal a great opportunity for using ubiquitous WiFi routers for high-resolution outdoor positioning, but also significant privacy implications of such side-channel location tracking.

  3. PDA-phone-based instant transmission of radiological images over a CDMA network by combining the PACS screen with a Bluetooth-interfaced local wireless link.

    PubMed

    Kim, Dong Keun; Yoo, Sun K; Park, Jeong Jin; Kim, Sun Ho

    2007-06-01

    Remote teleconsultation by specialists is important for timely, correct, and specialized emergency surgical and medical decision making. In this paper, we designed a new personal digital assistant (PDA)-phone-based emergency teleradiology system by combining cellular communication with Bluetooth-interfaced local wireless links. The mobility and portability resulting from the use of PDAs and wireless communication can provide a more effective means of emergency teleconsultation without requiring the user to be limited to a fixed location. Moreover, it enables synchronized radiological image sharing between the attending physician in the emergency room and the remote specialist on picture archiving and communication system terminals without distorted image acquisition. To enable rapid and fine-quality radiological image transmission over a cellular network in a secure manner, progressive compression and security mechanisms have been incorporated. The proposed system is tested over a code division Multiple Access 1x-Evolution Data-Only network to evaluate the performance and to demonstrate the feasibility of this system in a real-world setting.

  4. SIMON: Integration of mobility and parking solutions for people with disabilities.

    PubMed

    Ferreras, Alberto; Barberà, Ricard; Durá-Gil, Juan Vicente; Solaz, José; Muñoz, Eva María; Serrano, Manuel; Marqués, Antonio

    2015-01-01

    Mobility and parking in urban areas are often difficult for people with disabilities. Obstacles include lack of accessible information on routes, transport alternatives and parking availability, as well as fraud in the use of the specific services intended for these citizens. The SIMON project aims to improve this situation through the integration of different ICT solutions. SIMON is enhancing the European Parking Card for disable people with contactless technologies and integrates mobile solutions to support user unique identification in existing parking areas whilst preserving privacy. SIMON will also promote better mobility solutions for mobility including information, navigation and access to restricted areas.

  5. Earth Science Data for a Mobile Age

    NASA Astrophysics Data System (ADS)

    Oostra, D.; Chambers, L. H.; Lewis, P. M.; Baize, R.; Oots, P.; Rogerson, T.; Crecelius, S.; Coleman, T.

    2012-12-01

    Earth science data access needs to be interoperable and automatic. Recently, increasingly savvy data users combined with more complex web and mobile applications have placed increasing demands on how this Earth science data is being delivered to educators and students. The MY NASA DATA (MND) and S'COOL projects are developing a strategy to interact with the education community in the age of mobile devices and platforms. How can we provide data and meaningful scientific experiences to educational users through mobile technologies? This initiative will seek out existing technologies and stakeholders within the Earth Science community to identify datasets that are relevant and appropriate for mobile application development and use by the educational community. Targeting efforts within the educational community will give the project a better understanding of the previous attempts at data/mobile application use in the classroom and its problems. In addition, we will query developers and data providers on what successes and failures they've experienced in trying to provide data for applications designed on mobile platforms. This feedback will be implemented in new websites, applications and lessons that will provide authentic scientific experiences for students and end users. We want to create tools that help sort through the vast amounts of NASA data, and deliver it to users automatically. NASA provides millions of gigabytes of data that is publicly available through a large number of services spread across the World Wide Web. Accessing and navigating this data can be time consuming and problematic with variety of file types and methods for accessing this data. The MND project, through its' Live Access Server system, provides selected datasets that are relevant and targets National Standards of Learning for educators to easily integrate into existing curricula. In the future, we want to provide desired data to users with automatic updates, anticipate future data queries

  6. Concentration of Access to Information and Communication Technologies in the Municipalities of the Brazilian Legal Amazon.

    PubMed

    de Brito, Silvana Rossy; da Silva, Aleksandra do Socorro; Cruz, Adejard Gaia; Monteiro, Maurílio de Abreu; Vijaykumar, Nandamudi Lankalapalli; da Silva, Marcelino Silva; Costa, João Crisóstomo Weyl Albuquerque; Francês, Carlos Renato Lisboa

    2016-01-01

    This study fills demand for data on access and use of information and communication technologies (ICT) in the Brazilian legal Amazon, a region of localities with identical economic, political, and social problems. We use the 2010 Brazilian Demographic Census to compile data on urban and rural households (i) with computers and Internet access, (ii) with mobile phones, and (iii) with fixed phones. To compare the concentration of access to ICT in the municipalities of the Brazilian Amazon with other regions of Brazil, we use a concentration index to quantify the concentration of households in the following classes: with computers and Internet access, with mobile phones, with fixed phones, and no access. These data are analyzed along with municipal indicators on income, education, electricity, and population size. The results show that for urban households, the average concentration in the municipalities of the Amazon for computers and Internet access and for fixed phones is lower than in other regions of the country; meanwhile, that for no access and mobile phones is higher than in any other region. For rural households, the average concentration in the municipalities of the Amazon for computers and Internet access, mobile phones, and fixed phones is lower than in any other region of the country; meanwhile, that for no access is higher than in any other region. In addition, the study shows that education and income are determinants of inequality in accessing ICT in Brazilian municipalities and that the existence of electricity in rural households is directly associated with the ownership of ICT resources.

  7. Energy access and sustainable development

    NASA Astrophysics Data System (ADS)

    Kammen, Daniel M.; Alstone, Peter; Gershenson, Dimitry

    2015-03-01

    With 1.4 billion people lacking electricity to light their homes and provide other basic services, or to conduct business, and all of humanity (and particularly the poor) are in need of a decarbonized energy system can close the energy access gap and protect the global climate system. With particular focus on addressing the energy needs of the underserved, we present an analytical framework informed by historical trends and contemporary technological, social, and institutional conditions that clarifies the heterogeneous continuum of centralized on-grid electricity, autonomous mini- or community grids, and distributed, individual energy services. We find that the current day is a unique moment of innovation in decentralized energy networks based on super-efficient end-use technology and low-cost photovoltaics, supported by rapidly spreading information technology, particularly mobile phones. Collectively these disruptive technology systems could rapidly increase energy access, contributing to meeting the Millennium Development Goals for quality of life, while simultaneously driving action towards low-carbon, Earth-sustaining, energy systems.

  8. A comparison of the boomerang wire vascular access management system versus manual compression alone during percutaneous diagnostic and interventional cardiovascular procedures.

    PubMed

    Echeverria, Angela; Krajcer, Zvonimir

    2016-01-01

    Vascular closure devices allow for early sheath removal, allowing for earlier patient mobilization The Boomerang vascular access management system does not alter arterial integrity for future interventions Access site complications provide significant morbidity in diagnostic and therapeutic interventions.

  9. ACTS mobile SATCOM experiments

    NASA Technical Reports Server (NTRS)

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

    1993-01-01

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

  10. Mobile computing for radiology.

    PubMed

    Auffermann, William F; Chetlen, Alison L; Sharma, Arjun; Colucci, Andrew T; DeQuesada, Ivan M; Grajo, Joseph R; Kung, Justin W; Loehfelm, Thomas W; Sherry, Steven J

    2013-12-01

    The rapid advances in mobile computing technology have the potential to change the way radiology and medicine as a whole are practiced. Several mobile computing advances have not yet found application to the practice of radiology, while others have already been applied to radiology but are not in widespread clinical use. This review addresses several areas where radiology and medicine in general may benefit from adoption of the latest mobile computing technologies and speculates on potential future applications.

  11. Mobile health technology and the use of health-related mobile applications.

    PubMed

    Doyle-Lindrud, Susan

    2014-12-01

    Medical mobile applications (apps) are prevalent in society. Healthcare providers use them to obtain clinical information more efficiently, and healthcare consumers use them to gain greater personal control over their health management. With the increasing number of health-related mobile apps available, people in the oncology community now have many relevant apps at their fingertips. These apps are targeted to the oncology healthcare provider as well as the patient. This article will review a few popular apps and discuss the potential benefits of accessing information using apps and the possible risks associated with them.

  12. Exploring the mobility of mobile phone users

    NASA Astrophysics Data System (ADS)

    Csáji, Balázs Cs.; Browet, Arnaud; Traag, V. A.; Delvenne, Jean-Charles; Huens, Etienne; Van Dooren, Paul; Smoreda, Zbigniew; Blondel, Vincent D.

    2013-03-01

    Mobile phone datasets allow for the analysis of human behavior on an unprecedented scale. The social network, temporal dynamics and mobile behavior of mobile phone users have often been analyzed independently from each other using mobile phone datasets. In this article, we explore the connections between various features of human behavior extracted from a large mobile phone dataset. Our observations are based on the analysis of communication data of 100,000 anonymized and randomly chosen individuals in a dataset of communications in Portugal. We show that clustering and principal component analysis allow for a significant dimension reduction with limited loss of information. The most important features are related to geographical location. In particular, we observe that most people spend most of their time at only a few locations. With the help of clustering methods, we then robustly identify home and office locations and compare the results with official census data. Finally, we analyze the geographic spread of users’ frequent locations and show that commuting distances can be reasonably well explained by a gravity model.

  13. Identification and Classification of Orthogonal Frequency Division Multiple Access (OFDMA) Signals Used in Next Generation Wireless Systems

    DTIC Science & Technology

    2012-03-01

    interoperability for microwave access ZCC zero-terminating convolutional coding xv EXECUTIVE SUMMARY Many developing regions of the world that...consolidated and revised into the IEEE 802.16-2009 standard, which is the basis for mobile worldwide interoperability for microwave access (WiMAX...interoperability for microwave access (WiMAX) is based on the IEEE 802.16-2004 standard and mobile WiMAX is based on the IEEE 802.16e-2005 standard. Although

  14. A Novel Scheme of Fast-frequency Hopping Optical CDMA System with No-hit-zone Sequence

    NASA Astrophysics Data System (ADS)

    Ji, Jianhua; liu, Ling; Wang, Ke; Zhang, Zhipeng; Xu, Ming

    2013-09-01

    In traditional fast frequency-hopping OCDMA (FFH-OCDMA) system, beat noise and multiple-access interference are the main performance limitations, and complicated power control must be employed to eliminate the near-far effect. In this paper, a novel scheme of FFH-OCDMA with no-hit-zone sequence is proposed, which is named NHZ FFH-OCDMA. In NHZ FFH-OCDMA, the synchronization among users can be controlled within permissible time delay, and the code cross-correlation for different users equals zero. Therefore, near-far effect can be eliminated. Furthermore, beat noise and multiple-access interference also can be removed. Simulation of eight simultaneous users with dada rate 100 Mbit/s is demonstrated, where the fiber link consists of 50 km single-mode fiber, plus 5 km dispersion compensating fiber. Simulation results show that the near-far problem of NHZ FFH-OCDMA can be eliminated, and complicated power control can be removed. Therefore, this scheme is a good candidate for optical access network.

  15. A Mobile Data Application for the Fermi Mission

    NASA Astrophysics Data System (ADS)

    Stephens, Thomas E.; Science Support Center, Fermi

    2014-01-01

    With the ever increasing use of smartphones and tablets among scientists and the world at large, it becomes increasingly important for projects and missions to have mobile friendly access to their data. This access could come in the form of mobile friendly websites and/or native mobile applications that allow the users to explore or access the data. The Fermi Gamma-ray Space Telescope mission has begun work along the latter path. In this poster I present the current version of the Fermi Data Portal, a native mobile application for both Android and iOS devices that allows access to various high level public data products from the Fermi Science Support Center (FSSC), the Gamma-ray Coordinate Network (GCN), and other sources. While network access is required to download data, most of the data served by the app are stored locally and are available even when a network connection is not available. This poster discusses the application's features as well as the development experience and lessons learned so far along the way.

  16. A Mobile Data Application for the Fermi Mission

    NASA Astrophysics Data System (ADS)

    Stephens, T. E.

    2013-10-01

    With the ever increasing use of smartphones and tablets among scientists and the world at large, it becomes increasingly important for projects and missions to have mobile friendly access to their data. This access could come in the form of mobile friendly websites and/or native mobile applications that allow the users to explore or access the data. The Fermi Gamma-ray Space Telescope Mission has begun work along the latter path. In this poster I present the initial version of the Fermi Mobile Data Portal, a native application for both Android and iOS devices that allows access to various high level public data products from the Fermi Science Support Center (FSSC), the Gamma-ray Coordinate Network (GCN), and other sources. While network access is required to download data, most of the data served by the app are stored locally and are available even when a network connection is not available. This poster discusses the application's features as well as the development experience and lessons learned so far along the way.

  17. Mobile Life - Innovation in the Wild

    NASA Astrophysics Data System (ADS)

    Höök, Kristina

    After a decade of work in our research labs on mobile and ubiquitous technology, often formed by the early visions of ubiquitous computing, with the urge to move interaction from the desktop out into the wild, these technologies have now moved out into the world - into the wild. We are in the middle of a second IT-revolution, caused by the spread of mobile and ubiquitous services, in combination with a broad consumer-oriented market pull. The first ITrevolution, the introduction and deployment of Internet and the World Wide Web during the 1990’s, had a major impact on all parts of our society. As mobile, ubiquitous technology now becomes wide-spread, the design and evaluation of mobile services - i.e. information technology that can be accessed and used in virtually any setting - represents an important business arena for the IT- and telecom industry. Together we have to look for a sustainable web of work, leisure and ubiquitous technology we can call the mobile life.

  18. Influence of sociodemographics on human mobility

    PubMed Central

    Lenormand, Maxime; Louail, Thomas; Cantú-Ros, Oliva G.; Picornell, Miguel; Herranz, Ricardo; Arias, Juan Murillo; Barthelemy, Marc; Miguel, Maxi San; Ramasco, José J.

    2015-01-01

    Human mobility has been traditionally studied using surveys that deliver snapshots of population displacement patterns. The growing accessibility to ICT information from portable digital media has recently opened the possibility of exploring human behavior at high spatio-temporal resolutions. Mobile phone records, geolocated tweets, check-ins from Foursquare or geotagged photos, have contributed to this purpose at different scales, from cities to countries, in different world areas. Many previous works lacked, however, details on the individuals’ attributes such as age or gender. In this work, we analyze credit-card records from Barcelona and Madrid and by examining the geolocated credit-card transactions of individuals living in the two provinces, we find that the mobility patterns vary according to gender, age and occupation. Differences in distance traveled and travel purpose are observed between younger and older people, but, curiously, either between males and females of similar age. While mobility displays some generic features, here we show that sociodemographic characteristics play a relevant role and must be taken into account for mobility and epidemiological modelization. PMID:25993055

  19. Influence of sociodemographics on human mobility

    NASA Astrophysics Data System (ADS)

    Lenormand, Maxime; Louail, Thomas; Cantú-Ros, Oliva G.; Picornell, Miguel; Herranz, Ricardo; Arias, Juan Murillo; Barthelemy, Marc; Miguel, Maxi San; Ramasco, José J.

    2015-05-01

    Human mobility has been traditionally studied using surveys that deliver snapshots of population displacement patterns. The growing accessibility to ICT information from portable digital media has recently opened the possibility of exploring human behavior at high spatio-temporal resolutions. Mobile phone records, geolocated tweets, check-ins from Foursquare or geotagged photos, have contributed to this purpose at different scales, from cities to countries, in different world areas. Many previous works lacked, however, details on the individuals’ attributes such as age or gender. In this work, we analyze credit-card records from Barcelona and Madrid and by examining the geolocated credit-card transactions of individuals living in the two provinces, we find that the mobility patterns vary according to gender, age and occupation. Differences in distance traveled and travel purpose are observed between younger and older people, but, curiously, either between males and females of similar age. While mobility displays some generic features, here we show that sociodemographic characteristics play a relevant role and must be taken into account for mobility and epidemiological modelization.

  20. A Web Page Summarization for Mobile Phones

    NASA Astrophysics Data System (ADS)

    Hasegawa, Takaaki; Nishikawa, Hitoshi; Imamura, Kenji; Kikui, Gen'ichiro; Okumur, Manabu

    Recently, web pages for mobile devices are widely spread on the Internet and a lot of people can access web pages through search engines by mobile devices as well as personal computers. A summary of a retrieved web page is important because the people judge whether or not the page would be relevant to their information need according to the summary. In particular, the summary must be not only compact but also grammatical and meaningful when the users retrieve information using a mobile phone with a small screen. Most search engines seem to produce a snippet based on the keyword-in-context (KWIC) method. However, this simple method could not generate a refined summary suitable for mobile phones because of low grammaticality and content overlap with the page title. We propose a more suitable method to generate a snippet for mobile devices using sentence extraction and sentence compression methods. First, sentences are biased based on whether they include the query terms from the users or words that are relevant to the queries, as well as whether they do not overlap with the page title based on maximal marginal relevance (MMR). Second, the selected sentences are compressed based on their phrase coverage, which is measured by the scores of words, and their phrase connection probability measured based on the language model, according to the dependency structure converted from the sentence. The experimental results reveal the proposed method outperformed the KWIC method in terms of relevance judgment, grammaticality, non-redundancy and content coverage.