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. 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.

  3. 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.

  4. Evaluation of CDMA system capacity for mobile satellite system applications

    NASA Technical Reports Server (NTRS)

    Smith, Partrick O.; Geraniotis, Evaggelos A.

    1988-01-01

    A specific Direct-Sequence/Pseudo-Noise (DS/PN) Code-Division Multiple-Access (CDMA) mobile satellite system (MSAT) architecture is discussed. The performance of this system is evaluated in terms of the maximum number of active MSAT subscribers that can be supported at a given uncoded bit-error probability. The evaluation decouples the analysis of the multiple-access capability (i.e., the number of instantaneous user signals) from the analysis of the multiple-access mutliplier effect allowed by the use of CDMA with burst-modem operation. We combine the results of these two analyses and present numerical results for scenarios of interest to the mobile satellite system community.

  5. Performance, implementation and network management techniques for a European CDMA-based land-mobile satellite system

    NASA Astrophysics Data System (ADS)

    Arenaccio, S.; Vernucci, A.; Padovani, R.; Arcidiacono, A.

    Results of a detailed comparative performance assessment between two candidate access solutions for the provision of land-mobile services, i.e., FDMA and CDMA, for the European Land-Mobile Satellite Services (LMSS) provision are presented. The design of the CDMA access system and the network architecture, system procedures, network control, operation in fading environments, and implementation aspects of the system are described. The CDMA system is shown to yield superior traffic capability, despite the absence of polarization reuse due to payload design, especially in the second-generation era (multiple spot-beams). In this case, the advantage was found to be largely dependent on the traffic distribution across spot beams. Power control techniques are proposed to cope with the geographical disadvantage suffered by mobile stations located at the beam borders to compensate for fadings.

  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 beamforming in a CDMA mobile satellite communications system

    NASA Astrophysics Data System (ADS)

    Munoz-Garcia, Samuel G.

    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.

  8. 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.

  9. 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.

  10. 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.

  11. 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

  12. 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

  13. 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.

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

    DTIC Science & Technology

    2015-01-01

    This research has the purpose to establish a foundation for new classification and estimation of CDMA signals. Keywords: DS / CDMA signals, BPSK, QPSK...DEVELOPMENT OF THE AVERAGE LIKELIHOOD FUNCTION FOR CODE DIVISION MULTIPLE ACCESS ( CDMA ) USING BPSK AND QPSK SYMBOLS JANUARY 2015...To) OCT 2013 – OCT 2014 4. TITLE AND SUBTITLE DEVELOPMENT OF THE AVERAGE LIKELIHOOD FUNCTION FOR CODE DIVISION MULTIPLE ACCESS ( CDMA ) USING BPSK

  15. 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.

  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. A European mobile satellite system concept exploiting CDMA and OBP

    NASA Technical Reports Server (NTRS)

    Vernucci, A.; Craig, A. D.

    1993-01-01

    This paper describes a novel Land Mobile Satellite System (LMSS) concept applicable to networks allowing access to a large number of gateway stations ('Hubs'), utilizing low-cost Very Small Aperture Terminals (VSAT's). Efficient operation of the Forward-Link (FL) repeater can be achieved by adopting a synchronous Code Division Multiple Access (CDMA) technique, whereby inter-code interference (self-noise) is virtually eliminated by synchronizing orthogonal codes. However, with a transparent FL repeater, the requirements imposed by the highly decentralized ground segment can lead to significant efficiency losses. The adoption of a FL On-Board Processing (OBP) repeater is proposed as a means of largely recovering this efficiency impairment. The paper describes the network architecture, the system design and performance, the OBP functions and impact on implementation. The proposed concept, applicable to a future generation of the European LMSS, was developed in the context of a European Space Agency (ESA) study contract.

  18. 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.

  19. 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.

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

    DTIC Science & Technology

    2014-05-01

    lengths in the range of 22 to 213 and possibly higher. Keywords: DS / CDMA signals, classification, balanced CDMA load, synchronous CDMA , decision...likelihood ratio test (ALRT). We begin this classification problem by finding the size of the spreading matrix that generated the DS - CDMA signal. As...Theoretical Background The classification of DS / CDMA signals should not be confused with the problem of multiuser detection. The multiuser detection deals

  1. 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.

  2. Multiple access techniques and spectrum utilization of the GLOBALSTAR mobile satellite system

    NASA Astrophysics Data System (ADS)

    Louie, Ming; Cohen, Michel; Rouffet, Denis; Gilhousen, Klein S.

    The GLOBALSTAR System is a Low Earth Orbit (LEO) satellite-based mobile communications system that is interoperable with the current and future Public Land Mobile Network (PLMN). The GLOBALSTAR System concept is based upon technological advancement in two key areas: (1) the advancement in LEO satellite technology; (2) the advancement in cellular telephone technology, including the commercial applications of Code Division Multiple Access (CDMA) technologies, and of the most recent progress in Time Division Multiple Access technologies. The GLOBALSTAR System uses elements of CDMA, Frequency Division Multiple Access (FDMA), and Time Division Multiple Access (TDMA) technology, combining with satellite Multiple Beam Antenna (MBA) technology, to arrive at one of the most efficient modulation and multiple access system ever proposed for a satellite communications system. The technology used in GLOBALSTAR exploits the following techniques in obtaining high spectral efficiency and affordable cost per channel, with minimum coordination among different systems: power control, in open and closed loops, voice activation, spot beam satellite antenna for frequency reuse, weighted satellite antenna gain, multiple satellite coverage, and handoff between satellites. The GLOBALSTAR system design will use the following frequency bands: 1610-1626.5 MHz for up-link and 2483.5-2500 MHz for down-link.

  3. Traffic handling capability of a broadband indoor wireless network using CDMA multiple access

    NASA Astrophysics Data System (ADS)

    Zhang, Chang G.; Hafez, H. M.; Falconer, David D.

    1994-05-01

    CDMA (code division multiple access) may be an attractive technique for wireless access to broadband services because of its multiple access simplicity and other appealing features. In order to investigate traffic handling capabilities of a future network providing a variety of integrated services, this paper presents a study of a broadband indoor wireless network supporting high-speed traffic using CDMA multiple access. The results are obtained through the simulation of an indoor environment and the traffic capabilities of the wireless access to broadband 155.5 MHz ATM-SONET networks using the mm-wave band. A distributed system architecture is employed and the system performance is measured in terms of call blocking probability and dropping probability. The impacts of the base station density, traffic load, average holding time, and variable traffic sources on the system performance are examined. The improvement of system performance by implementing various techniques such as handoff, admission control, power control and sectorization are also investigated.

  4. 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.

  5. 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.

  6. Multiple Access Interference Reduction Using Received Response Code Sequence for DS-CDMA UWB System

    NASA Astrophysics Data System (ADS)

    Toh, Keat Beng; Tachikawa, Shin'ichi

    This paper proposes a combination of novel Received Response (RR) sequence at the transmitter and a Matched Filter-RAKE (MF-RAKE) combining scheme receiver system for the Direct Sequence-Code Division Multiple Access Ultra Wideband (DS-CDMA UWB) multipath channel model. This paper also demonstrates the effectiveness of the RR sequence in Multiple Access Interference (MAI) reduction for the DS-CDMA UWB system. It suggests that by using conventional binary code sequence such as the M sequence or the Gold sequence, there is a possibility of generating extra MAI in the UWB system. Therefore, it is quite difficult to collect the energy efficiently although the RAKE reception method is applied at the receiver. The main purpose of the proposed system is to overcome the performance degradation for UWB transmission due to the occurrence of MAI during multiple accessing in the DS-CDMA UWB system. The proposed system improves the system performance by improving the RAKE reception performance using the RR sequence which can reduce the MAI effect significantly. Simulation results verify that significant improvement can be obtained by the proposed system in the UWB multipath channel models.

  7. Performance Enhancement of MC-CDMA System through Novel Sensitive Bit Algorithm Aided Turbo Multi User Detection

    PubMed Central

    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. PMID:25714917

  8. Coherent/Noncoherent Detection of Coherent Optical Heterodyne DPSK-CDMA and MFSK-CDMA Signals

    DTIC Science & Technology

    1991-12-01

    AD-A246 215 NAVAL POSTGRADUATE SCHOOL Monterey, Californla DTI THESIS COHERENT/ NONCOHERENT DETECTION OF COHERENT OPTICAL HETERODYNE DPSK-CDMA AND...NO ~ ACCESSION NO 11TILE(ncud S~riy ~a~fiat~r)COHERENT/ NONCOHERENT DETECTION OF COHERENT OPTICAL HETERODYNE DPSK-CDMA AND MFSK-CDMA SIGNALS 12 PERSONAL...early optical fiber communication systems. Gas lasers are also disregarded for practical systems due to size and safety considerations, even though

  9. 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.

  10. Blind information-theoretic multiuser detection algorithms for DS-CDMA and WCDMA downlink systems.

    PubMed

    Waheed, Khuram; Salem, Fathi M

    2005-07-01

    Code division multiple access (CDMA) is based on the spread-spectrum technology and is a dominant air interface for 2.5G, 3G, and future wireless networks. For the CDMA downlink, the transmitted CDMA signals from the base station (BS) propagate through a noisy multipath fading communication channel before arriving at the receiver of the user equipment/mobile station (UE/MS). Classical CDMA single-user detection (SUD) algorithms implemented in the UE/MS receiver do not provide the required performance for modern high data-rate applications. In contrast, multi-user detection (MUD) approaches require a lot of a priori information not available to the UE/MS. In this paper, three promising adaptive Riemannian contra-variant (or natural) gradient based user detection approaches, capable of handling the highly dynamic wireless environments, are proposed. The first approach, blind multiuser detection (BMUD), is the process of simultaneously estimating multiple symbol sequences associated with all the users in the downlink of a CDMA communication system using only the received wireless data and without any knowledge of the user spreading codes. This approach is applicable to CDMA systems with relatively short spreading codes but becomes impractical for systems using long spreading codes. We also propose two other adaptive approaches, namely, RAKE -blind source recovery (RAKE-BSR) and RAKE-principal component analysis (RAKE-PCA) that fuse an adaptive stage into a standard RAKE receiver. This adaptation results in robust user detection algorithms with performance exceeding the linear minimum mean squared error (LMMSE) detectors for both Direct Sequence CDMA (DS-CDMA) and wide-band CDMA (WCDMA) systems under conditions of congestion, imprecise channel estimation and unmodeled multiple access interference (MAI).

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

    DTIC Science & Technology

    2009-10-01

    In our previous work, we compared the theoretical bit error rates of multi-carrier direct sequence code division multiple access (MC- DS - CDMA ) and...consider only those cases where MC- CDMA has higher frequency diversity than MC- DS - CDMA . Since increases in diversity yield diminishing gains, we conclude

  12. Contrast research of CDMA and GSM network optimization

    NASA Astrophysics Data System (ADS)

    Wu, Yanwen; Liu, Zehong; Zhou, Guangyue

    2004-03-01

    With the development of mobile telecommunication network, users of CDMA advanced their request of network service quality. While the operators also change their network management object from signal coverage to performance improvement. In that case, reasonably layout & optimization of mobile telecommunication network, reasonably configuration of network resource, improvement of the service quality, and increase the enterprise's core competition ability, all those have been concerned by the operator companies. This paper firstly looked into the flow of CDMA network optimization. Then it dissertated to some keystones in the CDMA network optimization, like PN code assignment, calculation of soft handover, etc. As GSM is also the similar cellular mobile telecommunication system like CDMA, so this paper also made a contrast research of CDMA and GSM network optimization in details, including the similarity and the different. In conclusion, network optimization is a long time job; it will run through the whole process of network construct. By the adjustment of network hardware (like BTS equipments, RF systems, etc.) and network software (like parameter optimized, configuration optimized, capacity optimized, etc.), network optimization work can improve the performance and service quality of the network.

  13. Optical CDMA components requirements

    NASA Astrophysics Data System (ADS)

    Chan, James K.

    1998-08-01

    Optical CDMA is a complementary multiple access technology to WDMA. Optical CDMA potentially provides a large number of virtual optical channels for IXC, LEC and CLEC or supports a large number of high-speed users in LAN. In a network, it provides asynchronous, multi-rate, multi-user communication with network scalability, re-configurability (bandwidth on demand), and network security (provided by inherent CDMA coding). However, optical CDMA technology is less mature in comparison to WDMA. The components requirements are also different from WDMA. We have demonstrated a video transport/switching system over a distance of 40 Km using discrete optical components in our laboratory. We are currently pursuing PIC implementation. In this paper, we will describe the optical CDMA concept/features, the demonstration system, and the requirements of some critical optical components such as broadband optical source, broadband optical amplifier, spectral spreading/de- spreading, and fixed/programmable mask.

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

    NASA Astrophysics Data System (ADS)

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

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

  15. Asynchronous, Decentralized DS-CDMA Using Feedback-Controlled Spreading Sequences for Time-Dispersive Channels

    NASA Astrophysics Data System (ADS)

    Miyatake, Teruhiko; Chiba, Kazuki; Hamamura, Masanori; Tachikawa, Shin'ichi

    We propose a novel asynchronous direct-sequence codedivision multiple access (DS-CDMA) using feedback-controlled spreading sequences (FCSSs) (FCSS/DS-CDMA). At the receiver of FCSS/DS-CDMA, the code-orthogonalizing filter (COF) produces a spreading sequence, and the receiver returns the spreading sequence to the transmitter. Then the transmitter uses the spreading sequence as its updated version. The performance of FCSS/DS-CDMA is evaluated over time-dispersive channels. The results indicate that FCSS/DS-CDMA greatly suppresses both the intersymbol interference (ISI) and multiple access interference (MAI) over time-invariant channels. FCSS/DS-CDMA is applicable to the decentralized multiple access.

  16. Neurological abnormalities associated with CDMA exposure.

    PubMed

    Hocking, B; Westerman, R

    2001-09-01

    Dysaesthesiae of the scalp and neurological abnormality after mobile phone use have been reported previously, but the roles of the phone per se or the radiations in causing these findings have been questioned. We report finding a neurological abnormality in a patient after accidental exposure of the left side of the face to mobile phone radiation [code division multiple access (CDMA)] from a down-powered mobile phone base station antenna. He had headaches, unilateral left blurred vision and pupil constriction, unilateral altered sensation on the forehead, and abnormalities of current perception thresholds on testing the left trigeminal ophthalmic nerve. His nerve function recovered during 6 months follow-up. His exposure was 0.015-0.06 mW/cm(2) over 1-2 h. The implications regarding health effects of radiofrequency radiation are discussed.

  17. Orthogonal Multi-Carrier DS-CDMA with Frequency-Domain Equalization

    NASA Astrophysics Data System (ADS)

    Tanaka, Ken; Tomeba, Hiromichi; Adachi, Fumiyuki

    Orthogonal multi-carrier direct sequence code division multiple access (orthogonal MC DS-CDMA) is a combination of orthogonal frequency division multiplexing (OFDM) and time-domain spreading, while multi-carrier code division multiple access (MC-CDMA) is a combination of OFDM and frequency-domain spreading. In MC-CDMA, a good bit error rate (BER) performance can be achieved by using frequency-domain equalization (FDE), since the frequency diversity gain is obtained. On the other hand, the conventional orthogonal MC DS-CDMA fails to achieve any frequency diversity gain. In this paper, we propose a new orthogonal MC DS-CDMA that can obtain the frequency diversity gain by applying FDE. The conditional BER analysis is presented. The theoretical average BER performance in a frequency-selective Rayleigh fading channel is evaluated by the Monte-Carlo numerical computation method using the derived conditional BER and is confirmed by computer simulation of the orthogonal MC DS-CDMA signal transmission.

  18. Performance of DS-CDMA with imperfect power control operating over a low earth orbiting satellite link

    NASA Astrophysics Data System (ADS)

    Vojcic, Branimir R.; Pickholtz, Raymond L.; Milstein, Laurence B.

    1994-05-01

    The analysis of both performance and capacity of direct sequence CDMA in terrestrial cellular systems has been addressed in the technical literature. It has been suggested that CDMA be used as a multiple access method for satellite systems as well, in particular for multispot beam Low Earth Orbit Satellites (LEOS). One is tempted to argue that since CDMA works well on terrestrial links, it will nominally work as well on satellite links. However, because there are fundamental differences in the characteristics of the two channels, such as larger time delays from the mobile to the base station and smaller multipath delay spreads on the satellite channels, the performance of CDMA on satellite links cannot always be accurately predicted from its performance on terrestrial channels. In this paper, we analytically derive the performance of a CDMA system which operates over a low earth orbiting satellite channel. We incorporate such effects as imperfect power control and dual-order diversity to obtain the average probability of error of a single user.

  19. 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.

  20. 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.

  1. System-Level Performance of Antenna Arrays in CDMA-Based Cellular Mobile Radio Systems

    NASA Astrophysics Data System (ADS)

    Czylwik, Andreas; Dekorsy, Armin

    2004-12-01

    Smart antennas exploit the inherent spatial diversity of the mobile radio channel, provide an antenna gain, and also enable spatial interference suppression leading to reduced intracell as well as intercell interference. Especially, for the downlink of future CDMA-based mobile communications systems, transmit beamforming is seen as a well-promising smart antenna technique. The main objective of this paper is to study the performance of diverse antenna array topologies when applied for transmit beamforming in the downlink of CDMA-based networks. In this paper, we focus on uniform linear array (ULA) and uniform circular array (UCA) topologies. For the ULA, we consider three-sector base stations with one linear array per sector. While recent research on downlink beamforming is often restricted to one single cell, this study takes into account the important impact of intercell interference on the performance by evaluating complete networks. Especially, from the operator perspective, system capacity and system coverage are very essential parameters of a cellular system so that there is a clear necessity of intensive system level investigations. Apart from delivering assessments on the performance of the diverse antenna array topologies, in the paper also different antenna array parameters, such as element spacing and beamwidth of the sector antennas, are optimized. Although we focus on the network level, fast channel fluctuations are taken into account by including them analytically into the signal-to-interference calculation.

  2. 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.

  3. A CDMA system implementation with dimming control for visible light communication

    NASA Astrophysics Data System (ADS)

    Chen, Danyang; Wang, Jianping; Jin, Jianli; Lu, Huimin; Feng, Lifang

    2018-04-01

    Visible light communication (VLC), using solid-state lightings to transmit information, has become a complement technology to wireless radio communication. As a realistic multiple access scheme for VLC system, code division multiple access (CDMA) has attracted more and more attentions in recent years. In this paper, we address and implement an improved CDMA scheme for VLC system. The simulation results reveal that the improved CDMA scheme not only supports multi-users' transmission but also maintains dimming value at about 50% and enhances the system efficiency. It can also realize the flexible dimming control by adjusting some parameters of system structure, which rarely affects the system BER performance. A real-time experimental VLC system with improved CDMA scheme is performed based on field programmable gate array (FPGA), reaching a good BER performance.

  4. Demonstration of the CDMA-mode CAOS smart camera.

    PubMed

    Riza, Nabeel A; Mazhar, Mohsin A

    2017-12-11

    Demonstrated is the code division multiple access (CDMA)-mode coded access optical sensor (CAOS) smart camera suited for bright target scenarios. Deploying a silicon CMOS sensor and a silicon point detector within a digital micro-mirror device (DMD)-based spatially isolating hybrid camera design, this smart imager first engages the DMD starring mode with a controlled factor of 200 high optical attenuation of the scene irradiance to provide a classic unsaturated CMOS sensor-based image for target intelligence gathering. Next, this CMOS sensor provided image data is used to acquire a focused zone more robust un-attenuated true target image using the time-modulated CDMA-mode of the CAOS camera. Using four different bright light test target scenes, successfully demonstrated is a proof-of-concept visible band CAOS smart camera operating in the CDMA-mode using up-to 4096 bits length Walsh design CAOS pixel codes with a maximum 10 KHz code bit rate giving a 0.4096 seconds CAOS frame acquisition time. A 16-bit analog-to-digital converter (ADC) with time domain correlation digital signal processing (DSP) generates the CDMA-mode images with a 3600 CAOS pixel count and a best spatial resolution of one micro-mirror square pixel size of 13.68 μm side. The CDMA-mode of the CAOS smart camera is suited for applications where robust high dynamic range (DR) imaging is needed for un-attenuated un-spoiled bright light spectrally diverse targets.

  5. MAI statistics estimation and analysis in a DS-CDMA system

    NASA Astrophysics Data System (ADS)

    Alami Hassani, A.; Zouak, M.; Mrabti, M.; Abdi, F.

    2018-05-01

    A primary limitation of Direct Sequence Code Division Multiple Access DS-CDMA link performance and system capacity is multiple access interference (MAI). To examine the performance of CDMA systems in the presence of MAI, i.e., in a multiuser environment, several works assumed that the interference can be approximated by a Gaussian random variable. In this paper, we first develop a new and simple approach to characterize the MAI in a multiuser system. In addition to statistically quantifying the MAI power, the paper also proposes a statistical model for both variance and mean of the MAI for synchronous and asynchronous CDMA transmission. We show that the MAI probability density function (PDF) is Gaussian for the equal-received-energy case and validate it by computer simulations.

  6. 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.

  7. Coded DS-CDMA Systems with Iterative Channel Estimation and no Pilot Symbols

    DTIC Science & Technology

    2010-08-01

    ar X iv :1 00 8. 31 96 v1 [ cs .I T ] 1 9 A ug 2 01 0 1 Coded DS - CDMA Systems with Iterative Channel Estimation and no Pilot Symbols Don...sequence code-division multiple-access ( DS - CDMA ) systems with quadriphase-shift keying in which channel estimation, coherent demodulation, and decoding...amplitude, phase, and the interference power spectral density (PSD) due to the combined interference and thermal noise is proposed for DS - CDMA systems

  8. 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

  9. Multichannel Baseband Processor for Wideband CDMA

    NASA Astrophysics Data System (ADS)

    Jalloul, Louay M. A.; Lin, Jim

    2005-12-01

    The system architecture of the cellular base station modem engine (CBME) is described. The CBME is a single-chip multichannel transceiver capable of processing and demodulating signals from multiple users simultaneously. It is optimized to process different classes of code-division multiple-access (CDMA) signals. The paper will show that through key functional system partitioning, tightly coupled small digital signal processing cores, and time-sliced reuse architecture, CBME is able to achieve a high degree of algorithmic flexibility while maintaining efficiency. The paper will also highlight the implementation and verification aspects of the CBME chip design. In this paper, wideband CDMA is used as an example to demonstrate the architecture concept.

  10. 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

  11. Layered video transmission over multirate DS-CDMA wireless systems

    NASA Astrophysics Data System (ADS)

    Kondi, Lisimachos P.; Srinivasan, Deepika; Pados, Dimitris A.; Batalama, Stella N.

    2003-05-01

    n this paper, we consider the transmission of video over wireless direct-sequence code-division multiple access (DS-CDMA) channels. A layered (scalable) video source codec is used and each layer is transmitted over a different CDMA channel. Spreading codes with different lengths are allowed for each CDMA channel (multirate CDMA). Thus, a different number of chips per bit can be used for the transmission of each scalable layer. For a given fixed energy value per chip and chip rate, the selection of a spreading code length affects the transmitted energy per bit and bit rate for each scalable layer. An MPEG-4 source encoder is used to provide a two-layer SNR scalable bitstream. Each of the two layers is channel-coded using Rate-Compatible Punctured Convolutional (RCPC) codes. Then, the data are interleaved, spread, carrier-modulated and transmitted over the wireless channel. A multipath Rayleigh fading channel is assumed. At the other end, we assume the presence of an antenna array receiver. After carrier demodulation, multiple-access-interference suppressing despreading is performed using space-time auxiliary vector (AV) filtering. The choice of the AV receiver is dictated by realistic channel fading rates that limit the data record available for receiver adaptation and redesign. Indeed, AV filter short-data-record estimators have been shown to exhibit superior bit-error-rate performance in comparison with LMS, RLS, SMI, or 'multistage nested Wiener' adaptive filter implementations. Our experimental results demonstrate the effectiveness of multirate DS-CDMA systems for wireless video transmission.

  12. Cognitive CDMA Channelization

    DTIC Science & Technology

    2010-03-01

    proposed scheme for power and code allocation for the secondary user is outlined in Fig. 2. V. SIMULATION STUDIES We consider a primary DS - CDMA system...DATES COVERED (From - To) January 2008 – June 2009 4. TITLE AND SUBTITLE COGNITIVE CDMA CHANNELIZATION 5a. CONTRACT NUMBER In-House 5b. GRANT...TELEPHONE NUMBER (Include area code) N/A Standard Form 298 (Rev. 8-98) Prescribed by ANSI Std. Z39.18 Cognitive CDMA Channelization Kanke

  13. 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.

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

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

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

    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.

  15. 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.

  16. Space-Time Processing for Tactical Mobile Ad Hoc Networks

    DTIC Science & Technology

    2010-05-01

    Spatial Diversity and Imperfect Channel Estimation on Wideband MC- DS - CDMA and MC- CDMA " IEEE Transactions on Communications, Vol. 57, No. 10, pp. 2988...include direct sequence code division multiple access ( DS - CDMA ), Frequency Hopped (FH) CDMA and Orthogonal Frequency Division Multiple Access (OFDMA...capability, LPD/LPI, and operability in non-continuous spectrum. In addition, FH- CDMA is robust to the near-far problem, while DS - CDMA requires

  17. Iterative Overlap FDE for Multicode DS-CDMA

    NASA Astrophysics Data System (ADS)

    Takeda, Kazuaki; Tomeba, Hiromichi; Adachi, Fumiyuki

    Recently, a new frequency-domain equalization (FDE) technique, called overlap FDE, that requires no GI insertion was proposed. However, the residual inter/intra-block interference (IBI) cannot completely be removed. In addition to this, for multicode direct sequence code division multiple access (DS-CDMA), the presence of residual interchip interference (ICI) after FDE distorts orthogonality among the spreading codes. In this paper, we propose an iterative overlap FDE for multicode DS-CDMA to suppress both the residual IBI and the residual ICI. In the iterative overlap FDE, joint minimum mean square error (MMSE)-FDE and ICI cancellation is repeated a sufficient number of times. The bit error rate (BER) performance with the iterative overlap FDE is evaluated by computer simulation.

  18. A Hybrid Path-Oriented Code Assignment CDMA-Based MAC Protocol for Underwater Acoustic Sensor Networks

    PubMed Central

    Chen, Huifang; Fan, Guangyu; Xie, Lei; Cui, Jun-Hong

    2013-01-01

    Due to the characteristics of underwater acoustic channel, media access control (MAC) protocols designed for underwater acoustic sensor networks (UWASNs) are quite different from those for terrestrial wireless sensor networks. Moreover, in a sink-oriented network with event information generation in a sensor field and message forwarding to the sink hop-by-hop, the sensors near the sink have to transmit more packets than those far from the sink, and then a funneling effect occurs, which leads to packet congestion, collisions and losses, especially in UWASNs with long propagation delays. An improved CDMA-based MAC protocol, named path-oriented code assignment (POCA) CDMA MAC (POCA-CDMA-MAC), is proposed for UWASNs in this paper. In the proposed MAC protocol, both the round-robin method and CDMA technology are adopted to make the sink receive packets from multiple paths simultaneously. Since the number of paths for information gathering is much less than that of nodes, the length of the spreading code used in the POCA-CDMA-MAC protocol is shorter greatly than that used in the CDMA-based protocols with transmitter-oriented code assignment (TOCA) or receiver-oriented code assignment (ROCA). Simulation results show that the proposed POCA-CDMA-MAC protocol achieves a higher network throughput and a lower end-to-end delay compared to other CDMA-based MAC protocols. PMID:24193100

  19. A hybrid path-oriented code assignment CDMA-based MAC protocol for underwater acoustic sensor networks.

    PubMed

    Chen, Huifang; Fan, Guangyu; Xie, Lei; Cui, Jun-Hong

    2013-11-04

    Due to the characteristics of underwater acoustic channel, media access control (MAC) protocols designed for underwater acoustic sensor networks (UWASNs) are quite different from those for terrestrial wireless sensor networks. Moreover, in a sink-oriented network with event information generation in a sensor field and message forwarding to the sink hop-by-hop, the sensors near the sink have to transmit more packets than those far from the sink, and then a funneling effect occurs, which leads to packet congestion, collisions and losses, especially in UWASNs with long propagation delays. An improved CDMA-based MAC protocol, named path-oriented code assignment (POCA) CDMA MAC (POCA-CDMA-MAC), is proposed for UWASNs in this paper. In the proposed MAC protocol, both the round-robin method and CDMA technology are adopted to make the sink receive packets from multiple paths simultaneously. Since the number of paths for information gathering is much less than that of nodes, the length of the spreading code used in the POCA-CDMA-MAC protocol is shorter greatly than that used in the CDMA-based protocols with transmitter-oriented code assignment (TOCA) or receiver-oriented code assignment (ROCA). Simulation results show that the proposed POCA-CDMA-MAC protocol achieves a higher network throughput and a lower end-to-end delay compared to other CDMA-based MAC protocols.

  20. Impact of dynamic rate coding aspects of mobile phone networks on forensic voice comparison.

    PubMed

    Alzqhoul, Esam A S; Nair, Balamurali B T; Guillemin, Bernard J

    2015-09-01

    Previous studies have shown that landline and mobile phone networks are different in their ways of handling the speech signal, and therefore in their impact on it. But the same is also true of the different networks within the mobile phone arena. There are two major mobile phone technologies currently in use today, namely the global system for mobile communications (GSM) and code division multiple access (CDMA) and these are fundamentally different in their design. For example, the quality of the coded speech in the GSM network is a function of channel quality, whereas in the CDMA network it is determined by channel capacity (i.e., the number of users sharing a cell site). This paper examines the impact on the speech signal of a key feature of these networks, namely dynamic rate coding, and its subsequent impact on the task of likelihood-ratio-based forensic voice comparison (FVC). Surprisingly, both FVC accuracy and precision are found to be better for both GSM- and CDMA-coded speech than for uncoded. Intuitively one expects FVC accuracy to increase with increasing coded speech quality. This trend is shown to occur for the CDMA network, but, surprisingly, not for the GSM network. Further, in respect to comparisons between these two networks, FVC accuracy for CDMA-coded speech is shown to be slightly better than for GSM-coded speech, particularly when the coded-speech quality is high, but in terms of FVC precision the two networks are shown to be very similar. Copyright © 2015 The Chartered Society of Forensic Sciences. Published by Elsevier Ireland Ltd. All rights reserved.

  1. Phosphorylation and gene expression of p53 are not affected in human cells exposed to 2.1425 GHz band CW or W-CDMA modulated radiation allocated to mobile radio base stations.

    PubMed

    Hirose, H; Sakuma, N; Kaji, N; Suhara, T; Sekijima, M; Nojima, T; Miyakoshi, J

    2006-09-01

    A large-scale in vitro study focusing on low-level radiofrequency (RF) fields from mobile radio base stations employing the International Mobile Telecommunication 2000 (IMT-2000) cellular system was conducted to test the hypothesis that modulated RF fields induce apoptosis or other cellular stress response that activate p53 or the p53-signaling pathway. First, we evaluated the response 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 by 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 apoptosis or any signs of stress. Human glioblastoma 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 24 or 48 h. Human IMR-90 fibroblasts from fetal lungs were exposed to both W-CDMA and CW radiation at a SAR of 80 mW/kg for 28 h. Under the RF field exposure conditions described above, no significant differences in the percentage of apoptotic cells were observed between the test groups exposed to RF signals and the sham-exposed negative controls, as evaluated by the Annexin V affinity assay. No significant differences in expression levels of phosphorylated p53 at serine 15 or total p53 were observed between the test groups and the negative controls by the bead-based multiplex assay. Moreover, microarray hybridization and real-time RT-PCR analysis showed no noticeable differences in gene expression of the subsequent downstream targets of p53 signaling involved in apoptosis between the test groups and the negative controls. Our results confirm that exposure to low-level RF signals up to 800 mW/kg does not induce p53-dependent apoptosis, DNA damage, or other stress response in human

  2. 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.

  3. 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.

  4. Intersystem Interference Reduction for Overlaid HAPS-Terrestrial CDMA System

    NASA Astrophysics Data System (ADS)

    Huang, Jeng-Ji; Wang, Wei-Ting; Li, Mingfu; Shiung, David; Ferng, Huei-Wen

    In this letter, we propose that directional antennas, combined with power management, be incorporated to reduce intersystem interference in a shared band overlaid high altitude platform station (HAPS)-terrestrial code division multiple access (CDMA) system. To eliminate the HAPS to terrestrial interference, the HAPS is accessed only via directional antennas under the proposed scheme. By doing so, the uplink power to the HAPS can accordingly be increased, so that the terrestrial to HAPS interference is also effectively suppressed.

  5. 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.

  6. 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.

  7. Effects of optical layer impairments on 2.5 Gb/s optical CDMA transmission.

    PubMed

    Feng, H; Mendez, A; Heritage, J; Lennon, W

    2000-07-03

    We conducted a computer simulation study to assess the effects of optical layer impairments on optical CDMA (O-CDMA) transmission of 8 asynchronous users at 2.5 Gb/s each user over a 214-km link. It was found that with group velocity dispersion compensation, two other residual effects, namely, the nonzero chromatic dispersion slope of the single mode fiber (which causes skew) and the non-uniform EDFA gain (which causes interference power level to exceed signal power level of some codes) degrade the signal to multi-access interference (MAI) ratio. In contrast, four wave mixing and modulation due to the Kerr and Raman contributions to the fiber nonlinear refractive index are less important. Current wavelength-division multiplexing (WDM) technologies, including dispersion management, EDFA gain flattening, and 3 rd order dispersion compensation, are sufficient to overcome the impairments to the O-CDMA transmission system that we considered.

  8. Throughput of Coded Optical CDMA Systems with AND Detectors

    NASA Astrophysics Data System (ADS)

    Memon, Kehkashan A.; Umrani, Fahim A.; Umrani, A. W.; Umrani, Naveed A.

    2012-09-01

    Conventional detection techniques used in optical code-division multiple access (OCDMA) systems are not optimal and result in poor bit error rate performance. This paper analyzes the coded performance of optical CDMA systems with AND detectors for enhanced throughput efficiencies and improved error rate performance. The results show that the use of AND detectors significantly improve the performance of an optical channel.

  9. FIR Filter of DS-CDMA UWB Modem Transmitter

    NASA Astrophysics Data System (ADS)

    Kang, Kyu-Min; Cho, Sang-In; Won, Hui-Chul; Choi, Sang-Sung

    This letter presents low-complexity digital pulse shaping filter structures of a direct sequence code division multiple access (DS-CDMA) ultra wide-band (UWB) modem transmitter with a ternary spreading code. The proposed finite impulse response (FIR) filter structures using a look-up table (LUT) have the effect of saving the amount of memory by about 50% to 80% in comparison to the conventional FIR filter structures, and consequently are suitable for a high-speed parallel data process.

  10. Adaptive Transmission and Channel Modeling for Frequency Hopping Communications

    DTIC Science & Technology

    2009-09-21

    proposed adaptive transmission method has much greater system capacity than conventional non-adaptive MC direct- sequence ( DS )- CDMA system. • We...several mobile radio systems. First, a new improved allocation algorithm was proposed for multicarrier code-division multiple access (MC- CDMA ) system...Multicarrier code-division multiple access (MC- CDMA ) system with adaptive frequency hopping (AFH) has attracted attention of researchers due to its

  11. Mobile Web and Accessibility

    NASA Astrophysics Data System (ADS)

    Hori, Masahiro; Kato, Takashi

    While focusing on the human-computer interaction side of the Web content delivery, this article discusses problems and prospects of the mobile Web and Web accessibility in terms of what lessons and experiences we have gained from Web accessibility and what they can say about the mobile Web. One aim is to draw particular attention to the importance of explicitly distinguishing between perceptual and cognitive aspects of the users’ interactions with the Web. Another is to emphasize the increased importance of scenario-based evaluation and remote testing for the mobile Web where the limited screen space and a variety of environmental factors of mobile use are critical design issues. A newly devised inspection type of evaluation method that focuses on the perceptual-cognitive distinction of accessibility and usability issues is presented as a viable means of scenario-based, remote testing for the Web.

  12. Effects of simultaneous combined exposure to CDMA and WCDMA electromagnetic fields on serum hormone levels in rats

    PubMed Central

    Jin, Yeung Bae; Choi, Hyung-Do; Kim, Byung Chan; Pack, Jeong-Ki; Kim, Nam; Lee, Yun-Sil

    2013-01-01

    Despite more than a decade of research on the endocrine system, there have been no published studies about the effects of concurrent exposure of radiofrequency electromagnetic fields (RF-EMF) on this system. The present study investigated the several parameters of the endocrine system including melatonin, thyroid stimulating hormone, stress hormone and sex hormone after code division multiple access (CDMA, 849 MHz) and wideband code division multiple access (WCDMA, 1.95 GHz) signals for simultaneous exposure in rats. Sprague-Dawley rats were exposed to RF-EMF signals for 45 min/day, 5 days/week for up to 8 weeks. The whole-body average specific absorption rate (SAR) of CDMA or WCDMA was 2.0 W/kg (total 4.0 W/kg). At 4 and 8 weeks after the experiment began, each experimental group's 40 rats (male 20, female 20) were autopsied. Exposure for 8 weeks to simultaneous CDMA and WCDMA RF did not affect serum levels in rats of melatonin, thyroid stimulating hormone (TSH), triiodothyronine (T3) and thyroxin (T4), adrenocorticotropic hormone (ACTH) and sex hormones (testosterone and estrogen) as assessed by the ELISA method. PMID:23239176

  13. Adaptive receiver structures for asynchronous CDMA systems

    NASA Astrophysics Data System (ADS)

    Rapajic, Predrag B.; Vucetic, Branka S.

    1994-05-01

    Adaptive linear and decision feedback receiver structures for coherent demodulation in asynchronous code division multiple access (CDMA) systems are considered. It is assumed that the adaptive receiver has no knowledge of the signature waveforms and timing of other users. The receiver is trained by a known training sequence prior to data transmission and continuously adjusted by an adaptive algorithm during data transmission. The proposed linear receiver is as simple as a standard single-user detector receiver consisting of a matched filter with constant coefficients, but achieves essential advantages with respect to timing recovery, multiple access interference elimination, near/far effect, narrowband and frequency-selective fading interference suppression, and user privacy. An adaptive centralized decision feedback receiver has the same advantages of the linear receiver but, in addition, achieves a further improvement in multiple access interference cancellation at the expense of higher complexity. The proposed receiver structures are tested by simulation over a channel with multipath propagation, multiple access interference, narrowband interference, and additive white Gaussian noise.

  14. Effects of short-term W-CDMA mobile phone base station exposure on women with or without mobile phone related symptoms.

    PubMed

    Furubayashi, Toshiaki; Ushiyama, Akira; Terao, Yasuo; Mizuno, Yoko; Shirasawa, Kei; Pongpaibool, Pornanong; Simba, Ally Y; Wake, Kanako; Nishikawa, Masami; Miyawaki, Kaori; Yasuda, Asako; Uchiyama, Mitsunori; Yamashita, Hitomi Kobayashi; Masuda, Hiroshi; Hirota, Shogo; Takahashi, Miyuki; Okano, Tomoko; Inomata-Terada, Satomi; Sokejima, Shigeru; Maruyama, Eiji; Watanabe, Soichi; Taki, Masao; Ohkubo, Chiyoji; Ugawa, Yoshikazu

    2009-02-01

    To investigate possible health effects of mobile phone use, we conducted a double-blind, cross-over provocation study to confirm whether subjects with mobile phone related symptoms (MPRS) are more susceptible than control subjects to the effect of electromagnetic fields (EMF) emitted from base stations. We sent questionnaires to 5,000 women and obtained 2,472 valid responses from possible candidates; from these, we recruited 11 subjects with MPRS and 43 controls. There were four EMF exposure conditions, each of which lasted 30 min: continuous, intermittent, and sham exposure with and without noise. Subjects were exposed to EMF of 2.14 GHz, 10 V/m (W-CDMA), in a shielded room to simulate whole-body exposure to EMF from base stations, although the exposure strength we used was higher than that commonly received from base stations. We measured several psychological and cognitive parameters pre- and post-exposure, and monitored autonomic functions. Subjects were asked to report on their perception of EMF and level of discomfort during the experiment. The MPRS group did not differ from the controls in their ability to detect exposure to EMF; nevertheless they consistently experienced more discomfort, regardless of whether or not they were actually exposed to EMF, and despite the lack of significant changes in their autonomic functions. Thus, the two groups did not differ in their responses to real or sham EMF exposure according to any psychological, cognitive or autonomic assessment. In conclusion, we found no evidence of any causal link between hypersensitivity symptoms and exposure to EMF from base stations. Copyright 2008 Wiley-Liss, Inc.

  15. 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…

  16. Exploiting Phase Diversity for CDMA2000 1X Smart Antenna Base Stations

    NASA Astrophysics Data System (ADS)

    Kim, Seongdo; Hyeon, Seungheon; Choi, Seungwon

    2004-12-01

    A performance analysis of an access channel decoder is presented which exploits a diversity gain due to the independent magnitude of received signals energy at each of the antenna elements of a smart-antenna base-station transceiver subsystem (BTS) operating in CDMA2000 1X signal environment. The objective is to enhance the data retrieval at cellsite during the access period, for which the optimal weight vector of the smart antenna BTS is not available. It is shown in this paper that the access channel decoder proposed in this paper outperforms the conventional one, which is based on a single antenna channel in terms of detection probability of access probe, access channel failure probability, and Walsh-code demodulation performance.

  17. 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.

  18. Multimedia transmission in MC-CDMA using adaptive subcarrier power allocation and CFO compensation

    NASA Astrophysics Data System (ADS)

    Chitra, S.; Kumaratharan, N.

    2018-02-01

    Multicarrier code division multiple access (MC-CDMA) system is one of the most effective techniques in fourth-generation (4G) wireless technology, due to its high data rate, high spectral efficiency and resistance to multipath fading. However, MC-CDMA systems are greatly deteriorated by carrier frequency offset (CFO) which is due to Doppler shift and oscillator instabilities. It leads to loss of orthogonality among the subcarriers and causes intercarrier interference (ICI). Water filling algorithm (WFA) is an efficient resource allocation algorithm to solve the power utilisation problems among the subcarriers in time-dispersive channels. The conventional WFA fails to consider the effect of CFO. To perform subcarrier power allocation with reduced CFO and to improve the capacity of MC-CDMA system, residual CFO compensated adaptive subcarrier power allocation algorithm is proposed in this paper. The proposed technique allocates power only to subcarriers with high channel to noise power ratio. The performance of the proposed method is evaluated using random binary data and image as source inputs. Simulation results depict that the bit error rate performance and ICI reduction capability of the proposed modified WFA offered superior performance in both power allocation and image compression for high-quality multimedia transmission in the presence of CFO and imperfect channel state information conditions.

  19. 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.

  20. Accessible Collaborative Learning Using Mobile Devices

    ERIC Educational Resources Information Center

    Wald, Mike; Li, Yunjia; Draffan, E. A.

    2014-01-01

    This paper describes accessible collaborative learning using mobile devices with mobile enhancements to Synote, the freely available, award winning, open source, web based application that makes web hosted recordings easier to access, search, manage, and exploit for all learners, teachers and other users. Notes taken live during lectures using…

  1. A Charrelation Matrix-Based Blind Adaptive Detector for DS-CDMA Systems

    PubMed Central

    Luo, Zhongqiang; Zhu, Lidong

    2015-01-01

    In this paper, a blind adaptive detector is proposed for blind separation of user signals and blind estimation of spreading sequences in DS-CDMA systems. The blind separation scheme exploits a charrelation matrix for simple computation and effective extraction of information from observation signal samples. The system model of DS-CDMA signals is modeled as a blind separation framework. The unknown user information and spreading sequence of DS-CDMA systems can be estimated only from the sampled observation signals. Theoretical analysis and simulation results show that the improved performance of the proposed algorithm in comparison with the existing conventional algorithms used in DS-CDMA systems. Especially, the proposed scheme is suitable for when the number of observation samples is less and the signal to noise ratio (SNR) is low. PMID:26287209

  2. A Charrelation Matrix-Based Blind Adaptive Detector for DS-CDMA Systems.

    PubMed

    Luo, Zhongqiang; Zhu, Lidong

    2015-08-14

    In this paper, a blind adaptive detector is proposed for blind separation of user signals and blind estimation of spreading sequences in DS-CDMA systems. The blind separation scheme exploits a charrelation matrix for simple computation and effective extraction of information from observation signal samples. The system model of DS-CDMA signals is modeled as a blind separation framework. The unknown user information and spreading sequence of DS-CDMA systems can be estimated only from the sampled observation signals. Theoretical analysis and simulation results show that the improved performance of the proposed algorithm in comparison with the existing conventional algorithms used in DS-CDMA systems. Especially, the proposed scheme is suitable for when the number of observation samples is less and the signal to noise ratio (SNR) is low.

  3. 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

  4. Ultrasonic Array for Obstacle Detection Based on CDMA with Kasami Codes

    PubMed Central

    Diego, Cristina; Hernández, Álvaro; Jiménez, Ana; Álvarez, 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. PMID:22247675

  5. 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.

  6. Mobile phone base station-emitted radiation does not induce phosphorylation of Hsp27.

    PubMed

    Hirose, H; Sakuma, N; Kaji, N; Nakayama, K; Inoue, K; Sekijima, M; Nojima, T; Miyakoshi, J

    2007-02-01

    An in vitro study focusing on the effects of low-level radiofrequency (RF) fields from mobile radio base stations employing the International Mobile Telecommunication 2000 (IMT-2000) cellular system was conducted to test the hypothesis that modulated RF fields act to induce phosphorylation and overexpression of heat shock protein hsp27. 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 activation or gene expression of hsp27 and other heat shock proteins (hsps). Human glioblastoma A172 cells were exposed to W-CDMA radiation at SARs of 80 and 800 mW/kg for 2-48 h, and CW radiation at 80 mW/kg for 24 h. Human IMR-90 fibroblasts from fetal lungs were exposed to W-CDMA at 80 and 800 mW/kg for 2 or 28 h, and CW at 80 mW/kg for 28 h. Under the RF field exposure conditions described above, no significant differences in the expression levels of phosphorylated hsp27 at serine 82 (hsp27[pS82]) were observed between the test groups exposed to W-CDMA or CW signal and the sham-exposed negative controls, as evaluated immediately after the exposure periods by bead-based multiplex assays. Moreover, no noticeable differences in the gene expression of hsps were observed between the test groups and the negative controls by DNA Chip analysis. Our results confirm that exposure to low-level RF field up to 800 mW/kg does not induce phosphorylation of hsp27 or expression of hsp gene family.

  7. 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.

  8. Performance Analysis of a New Coded TH-CDMA Scheme in Dispersive Infrared Channel with Additive Gaussian Noise

    NASA Astrophysics Data System (ADS)

    Hamdi, Mazda; Kenari, Masoumeh Nasiri

    2013-06-01

    We consider a time-hopping based multiple access scheme introduced in [1] for communication over dispersive infrared links, and evaluate its performance for correlator and matched filter receivers. In the investigated time-hopping code division multiple access (TH-CDMA) method, the transmitter benefits a low rate convolutional encoder. In this method, the bit interval is divided into Nc chips and the output of the encoder along with a PN sequence assigned to the user determines the position of the chip in which the optical pulse is transmitted. We evaluate the multiple access performance of the system for correlation receiver considering background noise which is modeled as White Gaussian noise due to its large intensity. For the correlation receiver, the results show that for a fixed processing gain, at high transmit power, where the multiple access interference has the dominant effect, the performance improves by the coding gain. But at low transmit power, in which the increase of coding gain leads to the decrease of the chip time, and consequently, to more corruption due to the channel dispersion, there exists an optimum value for the coding gain. However, for the matched filter, the performance always improves by the coding gain. The results show that the matched filter receiver outperforms the correlation receiver in the considered cases. Our results show that, for the same bandwidth and bit rate, the proposed system excels other multiple access techniques, like conventional CDMA and time hopping scheme.

  9. 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.

  10. 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.

  11. 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

  12. 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.

  13. Joint Frequency-Domain Equalization and Despreading for Multi-Code DS-CDMA Using Cyclic Delay Transmit Diversity

    NASA Astrophysics Data System (ADS)

    Yamamoto, Tetsuya; Takeda, Kazuki; Adachi, Fumiyuki

    Frequency-domain equalization (FDE) based on the minimum mean square error (MMSE) criterion can provide a better bit error rate (BER) performance than rake combining. To further improve the BER performance, cyclic delay transmit diversity (CDTD) can be used. CDTD simultaneously transmits the same signal from different antennas after adding different cyclic delays to increase the number of equivalent propagation paths. Although a joint use of CDTD and MMSE-FDE for direct sequence code division multiple access (DS-CDMA) achieves larger frequency diversity gain, the BER performance improvement is limited by the residual inter-chip interference (ICI) after FDE. In this paper, we propose joint FDE and despreading for DS-CDMA using CDTD. Equalization and despreading are simultaneously performed in the frequency-domain to suppress the residual ICI after FDE. A theoretical conditional BER analysis is presented for the given channel condition. The BER analysis is confirmed by computer simulation.

  14. Support vector machine multiuser receiver for DS-CDMA signals in multipath channels.

    PubMed

    Chen, S; Samingan, A K; Hanzo, L

    2001-01-01

    The problem of constructing an adaptive multiuser detector (MUD) is considered for direct sequence code division multiple access (DS-CDMA) signals transmitted through multipath channels. The emerging learning technique, called support vector machines (SVM), is proposed as a method of obtaining a nonlinear MUD from a relatively small training data block. Computer simulation is used to study this SVM MUD, and the results show that it can closely match the performance of the optimal Bayesian one-shot detector. Comparisons with an adaptive radial basis function (RBF) MUD trained by an unsupervised clustering algorithm are discussed.

  15. Empowering Learners with Mobile Open-Access Learning Initiatives

    ERIC Educational Resources Information Center

    Mills, Michael, Ed.; Wake, Donna, Ed.

    2017-01-01

    Education has been progressing at a rapid pace ever since educators have been able to harness the power of mobile technology. Open-access learning techniques provide more students with the opportunity to engage in educational opportunities that may have been previously restricted. "Empowering Learners with Mobile Open-Access Learning…

  16. Analysis of Optical CDMA Signal Transmission: Capacity Limits and Simulation Results

    NASA Astrophysics Data System (ADS)

    Garba, Aminata A.; Yim, Raymond M. H.; Bajcsy, Jan; Chen, Lawrence R.

    2005-12-01

    We present performance limits of the optical code-division multiple-access (OCDMA) networks. In particular, we evaluate the information-theoretical capacity of the OCDMA transmission when single-user detection (SUD) is used by the receiver. First, we model the OCDMA transmission as a discrete memoryless channel, evaluate its capacity when binary modulation is used in the interference-limited (noiseless) case, and extend this analysis to the case when additive white Gaussian noise (AWGN) is corrupting the received signals. Next, we analyze the benefits of using nonbinary signaling for increasing the throughput of optical CDMA transmission. It turns out that up to a fourfold increase in the network throughput can be achieved with practical numbers of modulation levels in comparison to the traditionally considered binary case. Finally, we present BER simulation results for channel coded binary and[InlineEquation not available: see fulltext.]-ary OCDMA transmission systems. In particular, we apply turbo codes concatenated with Reed-Solomon codes so that up to several hundred concurrent optical CDMA users can be supported at low target bit error rates. We observe that unlike conventional OCDMA systems, turbo-empowered OCDMA can allow overloading (more active users than is the length of the spreading sequences) with good bit error rate system performance.

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

    DTIC Science & Technology

    2008-08-29

    resulting in much larger system capacity than for a non-adaptive MC direct-sequence ( DS )- CDMA system. This conclusion is confirmed for realistic fading...system capacity than for a non-adaptive MC direct-sequence ( DS )- CDMA system. This conclusion is confirmed for realistic fading channels with correlated...transmission method exploits both frequency and multiuser diversity and improves on non-adaptive MC DS - CDMA sys- tems in [6]. In this paper, we focus on the

  18. 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.

  19. Multi-Hop Link Capacity of Multi-Route Multi-Hop MRC Diversity for a Virtual Cellular Network

    NASA Astrophysics Data System (ADS)

    Daou, Imane; Kudoh, Eisuke; Adachi, Fumiyuki

    In virtual cellular network (VCN), proposed for high-speed mobile communications, the signal transmitted from a mobile terminal is received by some wireless ports distributed in each virtual cell and relayed to the central port that acts as a gateway to the core network. In this paper, we apply the multi-route MHMRC diversity in order to decrease the transmit power and increase the multi-hop link capacity. The transmit power, the interference power and the link capacity are evaluated for DS-CDMA multi-hop VCN by computer simulation. The multi-route MHMRC diversity can be applied to not only DS-CDMA but also other access schemes (i. e. MC-CDMA, OFDM, etc.).

  20. Universal accessibility of "accessible" fitness and recreational facilities for persons with mobility disabilities.

    PubMed

    Arbour-Nicitopoulos, Kelly P; Ginis, Kathleen A Martin

    2011-01-01

    This study descriptively measured the universal accessibility of "accessible" fitness and recreational facilities for Ontarians living with mobility disabilities. The physical and social environments of 44 fitness and recreational facilities that identified as "accessible" were assessed using a modified version of the AIMFREE. None of the 44 facilities were completely accessible. Mean accessibility ratings ranged between 31 and 63 out of a possible 100. Overall, recreational facilities had higher accessibility scores than fitness centers, with significant differences found on professional support and training, entrance areas, and parking lot. A modest correlation was found between the availability of fitness programming and the overall accessibility of fitness-center specific facility areas. Overall, the physical and social environments of the 44 fitness and recreational facilities assessed were limited in their accessibility for persons with mobility disabilities. Future efforts should be directed at establishing and meeting universal accessibility guidelines for Canadian physical activity facilities.

  1. DPLL implementation in carrier acquisition and tracking for burst DS-CDMA receivers.

    PubMed

    Guan, Yun-feng; Zhang, Zhao-yang; Lai, Li-feng

    2003-01-01

    This paper presents the architectures, algorithms, and implementation considerations of the digital phase locked loop (DPLL) used for burst-mode packet DS-CDMA receivers. As we know, carrier offset is a rather challenging problem in CDMA system. According to different applications, different DPLL forms should be adopted to correct different maximum carrier offset in CDMA systems. One classical DPLL and two novel DPLL forms are discussed in the paper. The acquisition range of carrier offset can be widened by using the two novel DPLL forms without any performance degradation such as longer acquisition time or larger variance of the phase error. The maximum acquisition range is 1/(4T), where T is the symbol period. The design can be implemented by FPGA directly.

  2. Fast converging minimum probability of error neural network receivers for DS-CDMA communications.

    PubMed

    Matyjas, John D; Psaromiligkos, Ioannis N; Batalama, Stella N; Medley, Michael J

    2004-03-01

    We consider a multilayer perceptron neural network (NN) receiver architecture for the recovery of the information bits of a direct-sequence code-division-multiple-access (DS-CDMA) user. We develop a fast converging adaptive training algorithm that minimizes the bit-error rate (BER) at the output of the receiver. The adaptive algorithm has three key features: i) it incorporates the BER, i.e., the ultimate performance evaluation measure, directly into the learning process, ii) it utilizes constraints that are derived from the properties of the optimum single-user decision boundary for additive white Gaussian noise (AWGN) multiple-access channels, and iii) it embeds importance sampling (IS) principles directly into the receiver optimization process. Simulation studies illustrate the BER performance of the proposed scheme.

  3. 49 CFR 38.125 - Mobility aid accessibility.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... SPECIFICATIONS FOR TRANSPORTATION VEHICLES Intercity Rail Cars and Systems § 38.125 Mobility aid accessibility. (a)(1) General. All intercity rail cars, other than level entry cars, required to be accessible by... to be accessible, or mini-high platforms complying with § 38.113(d) are provided, the car is not...

  4. Current Impact, Future Prospects and Implications of Mobile Healthcare in India

    PubMed Central

    Kappal, Rishi; Mehndiratta, Amit; Anandaraj, Prabu; Tsanas, Athanasios

    2014-01-01

    India has a diverse geographical landscape and predominately rural population. Telemedicine is identified as one of the technological pillars to support healthcare services in this region, but is associated with high cost and complex infrastructure, thus restricting its wider use. Mobile-based healthcare (m-Health) services may provide a practical, promising alternative approach to support healthcare facilities. India has a high mobile user base, both in cities and in rural regions. The appropriate identification of mobile data transmission technology for healthcare services is vital to optimally use the available technology. In this article, we review current telecommunication systemsin India, specifically the evolving consensus on the need for CDMA (Code Division Multiple Access - a wireless technology used by leading international and national operators. This technology is deployed in 800MHz band making it economically viable and far reaching with high quality of services) to continue its operations in India along with mobile healthcare services. We also discuss how healthcare services may be extended using m-Health technologies, given the availability of telecommunications and related services. PMID:29755887

  5. Crew Access Arm arrival at Mobile Launcher

    NASA Image and Video Library

    2017-11-09

    A heavy-load transport truck carrying the Orion crew access arm arrives at the mobile launcher (ML) at NASA's Kennedy Space Center in Florida. The crew access arm will be installed at about the 274-foot level on the mobile launcher tower. It will rotate from its retracted position and interface with the Orion crew hatch location to provide entry to the Orion crew module. The Ground Systems Development and Operations Program is overseeing installation of umbilicals and launch accessories on the ML tower to prepare for Exploration Mission-1.

  6. 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 not...

  7. 36 CFR 1192.125 - Mobility aid accessibility.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 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 not...

  8. 36 CFR 1192.125 - Mobility aid accessibility.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 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 not...

  9. 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 not...

  10. Genetic Local Search for Optimum Multiuser Detection Problem in DS-CDMA Systems

    NASA Astrophysics Data System (ADS)

    Wang, Shaowei; Ji, Xiaoyong

    Optimum multiuser detection (OMD) in direct-sequence code-division multiple access (DS-CDMA) systems is an NP-complete problem. In this paper, we present a genetic local search algorithm, which consists of an evolution strategy framework and a local improvement procedure. The evolution strategy searches the space of feasible, locally optimal solutions only. A fast iterated local search algorithm, which employs the proprietary characteristics of the OMD problem, produces local optima with great efficiency. Computer simulations show the bit error rate (BER) performance of the GLS outperforms other multiuser detectors in all cases discussed. The computation time is polynomial complexity in the number of users.

  11. 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

  12. Effects of gestational exposure to 1.95-GHz W-CDMA signals for IMT-2000 cellular phones: Lack of embryotoxicity and teratogenicity in rats.

    PubMed

    Ogawa, Kumiko; Nabae, Kyoko; Wang, Jianqing; Wake, Kanako; Watanabe, So-ichi; Kawabe, Mayumi; Fujiwara, Osamu; Takahashi, Satoru; Ichihara, Toshio; Tamano, Seiko; Shirai, Tomoyuki

    2009-04-01

    The present study was designed to evaluate whether gestational exposure to an EMF targeting the head region, similar to that from cellular phones, might affect embryogenesis in rats. A 1.95-GHz wide-band code division multiple access (W-CDMA) signal, which is one applied for the International Mobile Telecommunication 2000 (IMT-2000) system and used for the freedom of mobile multimedia access (FOMA), was employed for exposure to the heads of four groups of pregnant CD(SD) IGS rats (20 per group) for gestational days 7-17. The exposure was performed for 90 min/day in the morning. The spatial average specific absorption rate (SAR) for individual brains was designed to be 0.67 and 2.0 W/kg with peak brain SARs of 3.1 and 7.0 W/kg for low (group 3) and high (group 4) exposures, respectively, and a whole-body average SAR less than 0.4 W/kg so as not to cause thermal effects due to temperature elevation. Control and sham exposure groups were also included. At gestational day 20, all dams were killed and fetuses were taken out by cesarean section. There were no differences in maternal body weight gain. No adverse effects of EMF exposure were observed on any reproductive and embryotoxic parameters such as number of live (243-271 fetuses), dead or resorbed embryos, placental weights, sex ratios, weights or external, visceral or skeletal abnormalities of live fetuses. (c) 2008 Wiley-Liss, Inc.

  13. Downlink Multihop Transmission Technique for Asymmetric Traffic Accommodation in DS-CDMA/FDD Cellular Communications

    NASA Astrophysics Data System (ADS)

    Mori, Kazuo; Naito, Katsuhiro; Kobayashi, Hideo

    This paper proposes an asymmetric traffic accommodation scheme using a multihop transmission technique for CDMA/FDD cellular communication systems. The proposed scheme exploits the multihop transmission to downlink packet transmissions, which require the large transmission power at their single-hop transmissions, in order to increase the downlink capacity. In these multihop transmissions, vacant uplink band is used for the transmissions from relay stations to destination mobile stations, and this leads more capacity enhancement in the downlink communications. The relay route selection method and power control method for the multihop transmissions are also investigated in the proposed scheme. The proposed scheme is evaluated by computer simulation and the results show that the proposed scheme can achieve better system performance.

  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. 49 CFR 38.125 - Mobility aid accessibility.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... mechanical, electrical or other system operates to ensure that cars do not move when the lift is in use. (3... SPECIFICATIONS FOR TRANSPORTATION VEHICLES Intercity Rail Cars and Systems § 38.125 Mobility aid accessibility. (a)(1) General. All intercity rail cars, other than level entry cars, required to be accessible by...

  16. 49 CFR 38.95 - Mobility aid accessibility.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... SPECIFICATIONS FOR TRANSPORTATION VEHICLES Commuter Rail Cars and Systems § 38.95 Mobility aid accessibility. (a)(1) General. All new commuter rail cars, other than level entry cars, covered by this subpart shall...(d) are provided, the car is not required to be equipped with a car-borne device. The access systems...

  17. 49 CFR 38.95 - Mobility aid accessibility.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... SPECIFICATIONS FOR TRANSPORTATION VEHICLES Commuter Rail Cars and Systems § 38.95 Mobility aid accessibility. (a)(1) General. All new commuter rail cars, other than level entry cars, covered by this subpart shall...(d) are provided, the car is not required to be equipped with a car-borne device. The access systems...

  18. 49 CFR 38.125 - Mobility aid accessibility.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... mechanical, electrical or other system operates to ensure that cars do not move when the lift is in use. (3... SPECIFICATIONS FOR TRANSPORTATION VEHICLES Intercity Rail Cars and Systems § 38.125 Mobility aid accessibility. (a)(1) General. All intercity rail cars, other than level entry cars, required to be accessible by...

  19. 49 CFR 38.95 - Mobility aid accessibility.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... SPECIFICATIONS FOR TRANSPORTATION VEHICLES Commuter Rail Cars and Systems § 38.95 Mobility aid accessibility. (a)(1) General. All new commuter rail cars, other than level entry cars, covered by this subpart shall...(d) are provided, the car is not required to be equipped with a car-borne device. The access systems...

  20. 49 CFR 38.125 - Mobility aid accessibility.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... mechanical, electrical or other system operates to ensure that cars do not move when the lift is in use. (3... SPECIFICATIONS FOR TRANSPORTATION VEHICLES Intercity Rail Cars and Systems § 38.125 Mobility aid accessibility. (a)(1) General. All intercity rail cars, other than level entry cars, required to be accessible by...

  1. 49 CFR 38.95 - Mobility aid accessibility.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... SPECIFICATIONS FOR TRANSPORTATION VEHICLES Commuter Rail Cars and Systems § 38.95 Mobility aid accessibility... rail cars, other than level entry cars, covered by this subpart shall provide a level-change mechanism... accessible, or mini-high platforms complying with § 38.93(d) are provided, the car is not required to be...

  2. 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.

  3. 49 CFR 38.125 - Mobility aid accessibility.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... SPECIFICATIONS FOR TRANSPORTATION VEHICLES Intercity Rail Cars and Systems § 38.125 Mobility aid accessibility... cars, other than level entry cars, required to be accessible by §§ 38.111 (a) and (e) of this subpart... complying with § 38.113(d) are provided, the car is not required to be equipped with a car-borne device. (b...

  4. 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

  5. Outdoor motivation moderates the effects of accessibility on mobility in old age.

    PubMed

    Kamin, Stefan T; Beyer, Anja; Lang, Frieder R

    2016-07-01

    Mobility plays a major role in healthy aging and social participation. This study explored whether accessibility problems in the housing environment are negatively associated with mobility in old age and whether this association is moderated by differences in an individual's preference for spending time outside the home (outdoor motivation). This article reports the results of a research project on mobility in old age. The project included a survey study of 120 community-dwelling older adults between 59 and 92 years of age (mean = 71.7 years, SD = 7.3 years) living in the metropolitan region of Nuremberg, Germany. Objective assessments were conducted in the participants' housing environment to evaluate the magnitude of accessibility problems. Accessibility problems were negatively associated with mobility. Interaction analyses suggested a buffering effect of outdoor motivation on this association, i.e. participants who reported a preference for spending time outside the home had a higher mobility in the face of accessibility problems as compared with those who preferred staying at home. Outdoor motivation may have protective effects for older adults when accessibility problems challenge mobility. These findings contribute to improving the understanding of how and under what circumstances older adults stay mobile and active in everyday life. Considering interindividual differences in outdoor motivation may binterventions and public health programs that are aimed at enhancing mobility and social participation in old age.

  6. 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).

  7. Interference Cancellation Technique Based on Discovery of Spreading Codes of Interference Signals and Maximum Correlation Detection for DS-CDMA System

    NASA Astrophysics Data System (ADS)

    Hettiarachchi, Ranga; Yokoyama, Mitsuo; Uehara, Hideyuki

    This paper presents a novel interference cancellation (IC) scheme for both synchronous and asynchronous direct-sequence code-division multiple-access (DS-CDMA) wireless channels. In the DS-CDMA system, the multiple access interference (MAI) and the near-far problem (NFP) are the two factors which reduce the capacity of the system. In this paper, we propose a new algorithm that is able to detect all interference signals as an individual MAI signal by maximum correlation detection. It is based on the discovery of all the unknowing spreading codes of the interference signals. Then, all possible MAI patterns so called replicas are generated as a summation of interference signals. And the true MAI pattern is found by taking correlation between the received signal and the replicas. Moreover, the receiver executes MAI cancellation in a successive manner, removing all interference signals by single-stage. Numerical results will show that the proposed IC strategy, which alleviates the detrimental effect of the MAI and the near-far problem, can significantly improve the system performance. Especially, we can obtain almost the same receiving characteristics as in the absense of interference for asynchrnous system when received powers are equal. Also, the same performances can be seen under any received power state for synchronous system.

  8. A discussion on mobile satellite system and the myths of CDMA and diversity revealed

    NASA Technical Reports Server (NTRS)

    Hart, Nicholas; Goerke, Thomas; Jahn, Axel

    1995-01-01

    The paper explores the myths and facts surrounding: link margins and constellation designs; the use of satellite diversity in a mobile satellite channel; trade-offs in multiple access technique. Different satellite constellations are presented, which are comparable with those used by the big LEO proponents, with the associated trade-offs in the system design. Propagation data and results from various narrowband and wideband measurement campaigns are used to illustrate the expected differences in service performance.

  9. Improving performance of DS-CDMA systems using chaotic complex Bernoulli spreading codes

    NASA Astrophysics Data System (ADS)

    Farzan Sabahi, Mohammad; Dehghanfard, Ali

    2014-12-01

    The most important goal of spreading spectrum communication system is to protect communication signals against interference and exploitation of information by unintended listeners. In fact, low probability of detection and low probability of intercept are two important parameters to increase the performance of the system. In Direct Sequence Code Division Multiple Access (DS-CDMA) systems, these properties are achieved by multiplying the data information in spreading sequences. Chaotic sequences, with their particular properties, have numerous applications in constructing spreading codes. Using one-dimensional Bernoulli chaotic sequence as spreading code is proposed in literature previously. The main feature of this sequence is its negative auto-correlation at lag of 1, which with proper design, leads to increase in efficiency of the communication system based on these codes. On the other hand, employing the complex chaotic sequences as spreading sequence also has been discussed in several papers. In this paper, use of two-dimensional Bernoulli chaotic sequences is proposed as spreading codes. The performance of a multi-user synchronous and asynchronous DS-CDMA system will be evaluated by applying these sequences under Additive White Gaussian Noise (AWGN) and fading channel. Simulation results indicate improvement of the performance in comparison with conventional spreading codes like Gold codes as well as similar complex chaotic spreading sequences. Similar to one-dimensional Bernoulli chaotic sequences, the proposed sequences also have negative auto-correlation. Besides, construction of complex sequences with lower average cross-correlation is possible with the proposed method.

  10. 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.

  11. 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…

  12. 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.

  13. An FPGA-based DS-CDMA multiuser demodulator employing adaptive multistage parallel interference cancellation

    NASA Astrophysics Data System (ADS)

    Li, Xinhua; Song, Zhenyu; Zhan, Yongjie; Wu, Qiongzhi

    2009-12-01

    Since the system capacity is severely limited, reducing the multiple access interfere (MAI) is necessary in the multiuser direct-sequence code division multiple access (DS-CDMA) system which is used in the telecommunication terminals data-transferred link system. In this paper, we adopt an adaptive multistage parallel interference cancellation structure in the demodulator based on the least mean square (LMS) algorithm to eliminate the MAI on the basis of overviewing various of multiuser dectection schemes. Neither a training sequence nor a pilot signal is needed in the proposed scheme, and its implementation complexity can be greatly reduced by a LMS approximate algorithm. The algorithm and its FPGA implementation is then derived. Simulation results of the proposed adaptive PIC can outperform some of the existing interference cancellation methods in AWGN channels. The hardware setup of mutiuser demodulator is described, and the experimental results based on it demonstrate that the simulation results shows large performance gains over the conventional single-user demodulator.

  14. 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.

  15. CP decomposition approach to blind separation for DS-CDMA system using a new performance index

    NASA Astrophysics Data System (ADS)

    Rouijel, Awatif; Minaoui, Khalid; Comon, Pierre; Aboutajdine, Driss

    2014-12-01

    In this paper, we present a canonical polyadic (CP) tensor decomposition isolating the scaling matrix. This has two major implications: (i) the problem conditioning shows up explicitly and could be controlled through a constraint on the so-called coherences and (ii) a performance criterion concerning the factor matrices can be exactly calculated and is more realistic than performance metrics used in the literature. Two new algorithms optimizing the CP decomposition based on gradient descent are proposed. This decomposition is illustrated by an application to direct-sequence code division multiplexing access (DS-CDMA) systems; computer simulations are provided and demonstrate the good behavior of these algorithms, compared to others in the literature.

  16. 36 CFR § 1192.125 - Mobility aid accessibility.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ..., electrical or other system operates to ensure that cars do not move when the lift is in use. (3) Emergency... VEHICLES 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...

  17. Mobile phone interventions for tuberculosis should ensure access to mobile phones to enhance equity - A prospective, observational cohort study in Peruvian shantytowns.

    PubMed

    Saunders, Matthew J; Wingfield, Tom; Tovar, Marco A; Herlihy, Niamh; Rocha, Claudio; Zevallos, Karine; Montoya, Rosario; Ramos, Eric; Datta, Sumona; Evans, Carlton A

    2018-06-04

    Mobile phone interventions have been advocated for tuberculosis care, but little is known about access of target populations to mobile phones. We studied mobile phone access amongst patients with tuberculosis, focusing on vulnerable patients and patients who later had adverse treatment outcomes. In a prospective cohort study in Callao, Peru, we recruited and interviewed 2,584 patients with tuberculosis between 2007-2013 and followed them until 2016 for adverse treatment outcomes using national treatment registers. Subsequently, we recruited a further 622 patients between 2016-2017. Data were analysed using logistic regression and by calculating relative risks (RR). Between 2007-2013, the proportion of the general population of Peru without mobile phone access averaged 7.8% but for patients with tuberculosis was 18% (p<0.001). Patients without access were more likely to hold a lower socioeconomic position, suffer from food insecurity and be older than 50 years (all p<0.01). Compared to patients with mobile phone access, patients without access at recruitment were more likely to subsequently have incomplete treatment (20% versus 13%, RR=1.5; p=0.001) or an adverse treatment outcome (29% versus 23% RR=1.3; p=0.006). Between 2016 and 2017, the proportion of patients without access dropped to 8.9% overall, but remained the same (18%) as in 2012 among the poorest third. Access to mobile phones among patients with tuberculosis is insufficient, and rarest in patients who are poorer and later have adverse treatment outcomes. Thus, mobile phone interventions to improve tuberculosis care may be least accessed by the priority populations for whom they are intended. Such interventions should ensure access to mobile phones to enhance equity. This article is protected by copyright. All rights reserved. This article is protected by copyright. All rights reserved.

  18. Urban search mobile platform modeling in hindered access conditions

    NASA Astrophysics Data System (ADS)

    Barankova, I. I.; Mikhailova, U. V.; Kalugina, O. B.; Barankov, V. V.

    2018-05-01

    The article explores the control system simulation and the design of the experimental model of the rescue robot mobile platform. The functional interface, a structural functional diagram of the mobile platform control unit, and a functional control scheme for the mobile platform of secure robot were modeled. The task of design a mobile platform for urban searching in hindered access conditions is realized through the use of a mechanical basis with a chassis and crawler drive, a warning device, human heat sensors and a microcontroller based on Arduino platforms.

  19. Bridging the digital divide: mobile access to personal health records among patients with diabetes.

    PubMed

    Graetz, Ilana; Huang, Jie; Brand, Richard J; Hsu, John; Yamin, Cyrus K; Reed, Mary E

    2018-01-01

    Some patients lack regular computer access and experience a digital divide that causes them to miss internet-based health innovations. The diffusion of smartphones has increased internet access across the socioeconomic spectrum, and increasing the channels through which patients can access their personal health records (PHRs) could help bridge the divide in PHR use. We examined PHR use through a computer-based Web browser or mobile device. Cross-sectional historical cohort analysis. Among adult patients in the diabetes registry of an integrated healthcare delivery system, we studied the devices used to access their PHR during 2016. Among 267,208 patients with diabetes, 68.1% used the PHR in 2016; 60.6% of all log-ins were via computer and 39.4% were via mobile device. Overall, 63.9% used it from both a computer and mobile device, 29.6% used only a computer, and 6.5% used only a mobile device. After adjustment, patients who were black, Hispanic, or Asian; lived in lower socioeconomic status (SES) neighborhoods; or had lower engagement were all significantly more likely to use the PHR only from a mobile device (P <.05). Patients using the PHR only via mobile device used it less frequently. Mobile-ready PHRs may increase access among patients facing a digital divide in computer use, disproportionately reaching racial/ethnic minorities and lower SES patients. Nonetheless, even with a mobile-optimized and app-accessible PHR, differences in PHR use by race/ethnicity and SES remain. Continued efforts are needed to increase equitable access to PHRs among patients with chronic conditions.

  20. 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

  1. AccessScope project: Accessible light microscope for users with upper limb mobility or visual impairments.

    PubMed

    Mansoor, Awais; Ahmed, Wamiq M; Samarapungavan, Ala; Cirillo, John; Schwarte, David; Robinson, J Paul; Duerstock, Bradley S

    2010-01-01

    A web-based application was developed to remotely view slide specimens and control all functions of a research-level light microscopy workstation, called AccessScope. Students and scientists with upper limb mobility and visual impairments are often unable to use a light microscope by themselves and must depend on others in its operation. Users with upper limb mobility impairments and low vision were recruited to assist in the design process of the AccessScope personal computer (PC) user interface. Participants with these disabilities were evaluated in their ability to use AccessScope to perform microscopical tasks. AccessScope usage was compared with inspecting prescanned slide images by grading participants' identification and understanding of histological features and knowledge of microscope operation. With AccessScope subjects were able to independently perform common light microscopy functions through an Internet browser by employing different PC pointing devices or accessibility software according to individual abilities. Subjects answered more histology and microscope usage questions correctly after first participating in an AccessScope test session. AccessScope allowed users with upper limb or visual impairments to successfully perform light microscopy without assistance. This unprecedented capability is crucial for students and scientists with disabilities to perform laboratory coursework or microscope-based research and pursue science, technology, engineering, and mathematics fields.

  2. 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.

  3. Approximate equiangular tight frames for compressed sensing and CDMA applications

    NASA Astrophysics Data System (ADS)

    Tsiligianni, Evaggelia; Kondi, Lisimachos P.; Katsaggelos, Aggelos K.

    2017-12-01

    Performance guarantees for recovery algorithms employed in sparse representations, and compressed sensing highlights the importance of incoherence. Optimal bounds of incoherence are attained by equiangular unit norm tight frames (ETFs). Although ETFs are important in many applications, they do not exist for all dimensions, while their construction has been proven extremely difficult. In this paper, we construct frames that are close to ETFs. According to results from frame and graph theory, the existence of an ETF depends on the existence of its signature matrix, that is, a symmetric matrix with certain structure and spectrum consisting of two distinct eigenvalues. We view the construction of a signature matrix as an inverse eigenvalue problem and propose a method that produces frames of any dimensions that are close to ETFs. Due to the achieved equiangularity property, the so obtained frames can be employed as spreading sequences in synchronous code-division multiple access (s-CDMA) systems, besides compressed sensing.

  4. Joint channel estimation and multi-user detection for multipath fading channels in DS-CDMA systems

    NASA Astrophysics Data System (ADS)

    Wu, Sau-Hsuan; Kuo, C.-C. Jay

    2002-11-01

    The technique of joint blind channel estimation and multiple access interference (MAI) suppression for an asynchronous code-division multiple-access (CDMA) system is investigated in this research. To identify and track dispersive time-varying fading channels and to avoid the phase ambiguity that come with the second-order statistic approaches, a sliding-window scheme using the expectation maximization (EM) algorithm is proposed. The complexity of joint channel equalization and symbol detection for all users increases exponentially with system loading and the channel memory. The situation is exacerbated if strong inter-symbol interference (ISI) exists. To reduce the complexity and the number of samples required for channel estimation, a blind multiuser detector is developed. Together with multi-stage interference cancellation using soft outputs provided by this detector, our algorithm can track fading channels with no phase ambiguity even when channel gains attenuate close to zero.

  5. Mobile phone base station radiation does not affect neoplastic transformation in BALB/3T3 cells.

    PubMed

    Hirose, H; Suhara, T; Kaji, N; Sakuma, N; Sekijima, M; Nojima, T; Miyakoshi, J

    2008-01-01

    A large-scale in vitro study focusing on low-level radiofrequency (RF) fields from mobile radio base stations employing the International Mobile Telecommunication 2000 (IMT-2000) cellular system was conducted to test the hypothesis that modulated RF fields affect malignant transformation or other cellular stress responses. Our group previously reported that DNA strand breaks were not induced in human cells exposed to 2.1425 GHz Wideband Code Division Multiple Access (W-CDMA) radiation up to 800 mW/kg from mobile radio base stations employing the IMT-2000 cellular system. In the current study, BALB/3T3 cells were continuously exposed to 2.1425 GHz W-CDMA RF fields at specific absorption rates (SARs) of 80 and 800 mW/kg for 6 weeks and malignant cell transformation was assessed. In addition, 3-methylcholanthrene (MCA)-treated cells were exposed to RF fields in a similar fashion, to assess for effects on tumor promotion. Finally, the effect of RF fields on tumor co-promotion was assessed in BALB/3T3 cells initiated with MCA and co-exposed to 12-O-tetradecanoylphorbol-13-acetate (TPA). At the end of the incubation period, transformation dishes were fixed, stained with Giemsa, and scored for morphologically transformed foci. No significant differences in transformation frequency were observed between the test groups exposed to RF signals and the sham-exposed negative controls in the non-, MCA-, or MCA plus TPA-treated cells. Our studies found no evidence to support the hypothesis that RF fields may affect malignant transformation. Our results suggest that exposure to low-level RF radiation of up to 800 mW/kg does not induce cell transformation, which causes tumor formation. (c) 2007 Wiley-Liss, Inc.

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

    DTIC Science & Technology

    2013-10-01

    the access-granter knowing the identity of access requester beforehand and authenticating the requester, can no longer be applied. Mobile Wallet Cloud...TktC) for a reservation and con- tacts the user’s mobile wallet provider (MobWC) to purchase the ticket from TktC. For accessing different services...receiving regular services. For example, the human user in our scenario can be an elite member with the mobile wallet service provider that

  7. An Architecture for Enabling Migration of Tactical Networks to Future Flexible Ad Hoc WBWF

    DTIC Science & Technology

    2010-09-01

    Requirements Several multiple access schemes TDMA OFDMA SC-OFDMA, FH- CDMA , DS - CDMA , hybrid access schemes, transitions between them Dynamic...parameters algorithms depend on the multiple access scheme If DS - CDMA : handling of macro-diversity (linked to cooperative routing) TDMA and/of OFDMA...Transport format Ciphering @MAC/RLC level : SCM Physical layer (PHY) : signal processing (mod, FEC, etc) CDMA : macro-diversity CDMA , OFDMA

  8. 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

  9. Mobile Recommender Apps with Privacy Management for Accessible and Usable Technologies.

    PubMed

    Hersh, Marion; Leporini, Barbara

    2017-01-01

    The paper presents the preliminary results of an ongoing survey of the use of computers and mobile devices, interest in recommender apps and knowledge and concerns about privacy issues amongst English and Italian speaking disabled people. Participants were found to be regular users of computers and mobile devices for a range of applications. They were interested in recommender apps for household items, computer software and apps that met their accessibility and other requirements. They showed greater concerns about controlling access to personal data of different types than this data being retained by the computer or mobile device. They were also willing to make tradeoffs to improve device performance.

  10. Access to cancer screening for women with mobility disabilities.

    PubMed

    Angus, Jan; Seto, Lisa; Barry, Nancy; Cechetto, Naomi; Chandani, Samira; Devaney, Julie; Fernando, Sharmini; Muraca, Linda; Odette, Fran

    2012-03-01

    Women with mobility disabilities are less likely to access cancer screening, even when they have a primary care provider. The Gateways to Cancer Screening project was initiated to document the challenges for women with disabilities in their access and experiences of screening for breast, cervical and colorectal cancer. The study followed the tenets of participatory action research. Five peer-led focus groups were held with 24 women with mobility disabilities. Study participants identified multiple and interacting institutional barriers to cancer screening. Their discussions highlighted the complex work of (1) arranging and attending health-related appointments, (2) confronting normative assumptions about women's bodies and (3) securing reliable health care and information. These overlapping, mutually reinforcing issues interact to shape how women with disabilities access and experience cancer screening. We explore implications for redesign of cancer screening services and education of health providers, providing specific recommendations suggested by our participants and the findings.

  11. A General Model for Performance Evaluation in DS-CDMA Systems with Variable Spreading Factors

    NASA Astrophysics Data System (ADS)

    Chiaraluce, Franco; Gambi, Ennio; Righi, Giorgia

    This paper extends previous analytical approaches for the study of CDMA systems to the relevant case of multipath environments where users can operate at different bit rates. This scenario is of interest for the Wideband CDMA strategy employed in UMTS, and the model permits the performance comparison of classic and more innovative spreading signals. The method is based on the characteristic function approach, that allows to model accurately the various kinds of interferences. Some numerical examples are given with reference to the ITU-R M. 1225 Recommendations, but the analysis could be extended to different channel descriptions.

  12. Uplink Packet-Data Scheduling in DS-CDMA Systems

    NASA Astrophysics Data System (ADS)

    Choi, Young Woo; Kim, Seong-Lyun

    In this letter, we consider the uplink packet scheduling for non-real-time data users in a DS-CDMA system. As an effort to jointly optimize throughput and fairness, we formulate a time-span minimization problem incorporating the time-multiplexing of different simultaneous transmission schemes. Based on simple rules, we propose efficient scheduling algorithms and compare them with the optimal solution obtained by linear programming.

  13. Iterative MMSE Detection for MIMO/BLAST DS-CDMA Systems in Frequency Selective Fading Channels - Achieving High Performance in Fully Loaded Systems

    NASA Astrophysics Data System (ADS)

    Silva, João Carlos; Souto, Nuno; Cercas, Francisco; Dinis, Rui

    A MMSE (Minimum Mean Square Error) DS-CDMA (Direct Sequence-Code Division Multiple Access) receiver coupled with a low-complexity iterative interference suppression algorithm was devised for a MIMO/BLAST (Multiple Input, Multiple Output / Bell Laboratories Layered Space Time) system in order to improve system performance, considering frequency selective fading channels. The scheme is compared against the simple MMSE receiver, for both QPSK and 16QAM modulations, under SISO (Single Input, Single Output) and MIMO systems, the latter with 2Tx by 2Rx and 4Tx by 4Rx (MIMO order 2 and 4 respectively) antennas. To assess its performance in an existing system, the uncoded UMTS HSDPA (High Speed Downlink Packet Access) standard was considered.

  14. 49 CFR 38.95 - Mobility aid accessibility.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... mechanical, electrical or other system operates to ensure that cars do not move when the lift is in use. (3... SPECIFICATIONS FOR TRANSPORTATION VEHICLES Commuter Rail Cars and Systems § 38.95 Mobility aid accessibility. (a)(1) General. All new commuter rail cars, other than level entry cars, covered by this subpart shall...

  15. 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

  16. Response to "Expanding Access to Learning with Mobile Digital Devices"

    ERIC Educational Resources Information Center

    Vanek, Jen

    2017-01-01

    In his article "Expanding Access to Learning with Mobile Digital Devices" (EJ1150752), Jeff Carter recommended a balanced perspective when measuring the potential of mobile learning to redefine teaching and learning for adults with basic skills needs. In response to Carter's article, the author makes some recommendations that she thinks…

  17. Food Access Patterns and Barriers among Midlife and Older Adults with Mobility Disabilities

    PubMed Central

    Huang, Deborah L.; Rosenberg, Dori E.; Simonovich, Shannon D.; Belza, Basia

    2012-01-01

    We examined where midlife and older adults with a mobility disability accessed food outside the home in King County, Washington, USA, how they travelled to these food destinations, and facilitators and barriers to food access using qualitative interviews. Thirty-five adults aged ≥50 years with a mobility disability (defined as use of an assistive device for mobility) were interviewed. Supplemental objective information was obtained from a Global Positioning System device worn by participants for 3 days. Participants primarily accessed food at grocery stores, restaurants, and coffee shops/cafés. The most common transportation modes were walking, obtaining a ride from friends, motorized chair/scooter, and public transit. Location and proximity of food destinations were factors affecting participants' ability to access these destinations. Adequate space, ease of entry, available amenities such as restrooms, and helpful people were facilitators for participants to access food outside the home. PMID:23056944

  18. 36 CFR 1192.95 - Mobility aid accessibility.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 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 or...

  19. 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 or...

  20. 36 CFR 1192.95 - Mobility aid accessibility.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 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 or...

  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 or...

  2. 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…

  3. An access alternative for mobile satellite networks

    NASA Technical Reports Server (NTRS)

    Wu, W. W.

    1988-01-01

    Conceptually, this paper discusses strategies of digital satellite communication networks for a very large number of low density traffic stations. These stations can be either aeronautical, land mobile, or maritime. The techniques can be applied to international, domestic, regional, and special purpose satellite networks. The applications can be commercial, scientific, military, emergency, navigational or educational. The key strategy is the use of a non-orthogonal access method, which tolerates overlapping signals. With n being either time or frequency partitions, and with a single overlapping signal allowed, a low cost mobile satellite system can be designed with n squared (n squared + n + 1) number of terminals.

  4. A Space-Time Signal Decomposition Algorithm for Downlink MIMO DS-CDMA Receivers

    NASA Astrophysics Data System (ADS)

    Wang, Yung-Yi; Fang, Wen-Hsien; Chen, Jiunn-Tsair

    We propose a dimension reduction algorithm for the receiver of the downlink of direct-sequence code-division multiple access (DS-CDMA) systems in which both the transmitters and the receivers employ antenna arrays of multiple elements. To estimate the high order channel parameters, we develop a layered architecture using dimension-reduced parameter estimation algorithms to estimate the frequency-selective multipath channels. In the proposed architecture, to exploit the space-time geometric characteristics of multipath channels, spatial beamformers and constrained (or unconstrained) temporal filters are adopted for clustered-multipath grouping and path isolation. In conjunction with the multiple access interference (MAI) suppression techniques, the proposed architecture jointly estimates the direction of arrivals, propagation delays, and fading amplitudes of the downlink fading multipaths. With the outputs of the proposed architecture, the signals of interest can then be naturally detected by using path-wise maximum ratio combining. Compared to the traditional techniques, such as the Joint-Angle-and-Delay-Estimation (JADE) algorithm for DOA-delay joint estimation and the space-time minimum mean square error (ST-MMSE) algorithm for signal detection, computer simulations show that the proposed algorithm substantially mitigate the computational complexity at the expense of only slight performance degradation.

  5. 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.

  6. Performance Comparison of Orthogonal and Quasi-orthogonal Codes in Quasi-Synchronous Cellular CDMA Communication

    NASA Astrophysics Data System (ADS)

    Jos, Sujit; Kumar, Preetam; Chakrabarti, Saswat

    Orthogonal and quasi-orthogonal codes are integral part of any DS-CDMA based cellular systems. Orthogonal codes are ideal for use in perfectly synchronous scenario like downlink cellular communication. Quasi-orthogonal codes are preferred over orthogonal codes in the uplink communication where perfect synchronization cannot be achieved. In this paper, we attempt to compare orthogonal and quasi-orthogonal codes in presence of timing synchronization error. This will give insight into the synchronization demands in DS-CDMA systems employing the two classes of sequences. The synchronization error considered is smaller than chip duration. Monte-Carlo simulations have been carried out to verify the analytical and numerical results.

  7. 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.

  8. Performance Analysis of Direct-Sequence Code-Division Multiple-Access Communications with Asymmetric Quadrature Phase-Shift-Keying Modulation

    NASA Technical Reports Server (NTRS)

    Wang, C.-W.; Stark, W.

    2005-01-01

    This article considers a quaternary direct-sequence code-division multiple-access (DS-CDMA) communication system with asymmetric quadrature phase-shift-keying (AQPSK) modulation for unequal error protection (UEP) capability. Both time synchronous and asynchronous cases are investigated. An expression for the probability distribution of the multiple-access interference is derived. The exact bit-error performance and the approximate performance using a Gaussian approximation and random signature sequences are evaluated by extending the techniques used for uniform quadrature phase-shift-keying (QPSK) and binary phase-shift-keying (BPSK) DS-CDMA systems. Finally, a general system model with unequal user power and the near-far problem is considered and analyzed. The results show that, for a system with UEP capability, the less protected data bits are more sensitive to the near-far effect that occurs in a multiple-access environment than are the more protected bits.

  9. The COMPOSE Project

    NASA Astrophysics Data System (ADS)

    Balletta, P.; Biagini, M.; Gallinaro, G.; Vernucci, A.

    2003-07-01

    This paper provides an overview of the on-going project COMPOSE, an EC co-funded project aiming to define, specify and validate an innovative mobile-services scenario in support of travellers, and to demonstrate the effectiveness of the new proposed location-based value-added services. COMPOSE is supported by organisations belonging to numerous categories covering, as a whole, the entire value-chain of infomobility services provision to the final user. The project team comprises, in addition to the affiliations of the authors, also Teleatlas (NL), ARS T&TT (NL), Alcatel-Bell Space (B), Skysoft (P), Hitech Marketing (A) and MobileGis (IR). The paper describes the services that will be offered to users, encompassing both the pre-trip and the on-trip framework, presents the overall hybrid system architecture also including a via-satellite component based upon the Wideband-CDMA (W-CDMA) technique adopted in UMTS, discusses the access solutions envisaged for that component permitting multiple feeder-link stations to share the CDMA multiplex capacity by directly transmitting their codes to the satellite, and illustrates the results of some computer simulations intended to assess the performance of said access solutions, with regard to the effects of the inevitable up- link frequency errors and transponder non-linearity.

  10. Robust MOE Detector for DS-CDMA Systems with Signature Waveform Mismatch

    NASA Astrophysics Data System (ADS)

    Lin, Tsui-Tsai

    In this letter, a decision-directed MOE detector with excellent robustness against signature waveform mismatch is proposed for DS-CDMA systems. Both the theoretic analysis and computer simulation results demonstrate that the proposed detector can provide better SINR performance than that of conventional detectors.

  11. Accessibility of health clubs for people with mobility disabilities and visual impairments.

    PubMed

    Rimmer, James H; Riley, Barth; Wang, Edward; Rauworth, Amy

    2005-11-01

    We sought to examine the accessibility of health clubs to persons with mobility disabilities and visual impairments. We assessed 35 health clubs and fitness facilities as part of a national field trial of a new instrument, Accessibility Instruments Measuring Fitness and Recreation Environments (AIMFREE), designed to assess accessibility of fitness facilities in the following domains: (1) built environment, (2) equipment, (3) swimming pools, (4) information, (5) facility policies, and (6) professional behavior. All facilities had a low to moderate level of accessibility. Some of the deficiencies concerned specific Americans with Disabilities Act guidelines pertaining to the built environment, whereas other deficiency areas were related to aspects of the facilities' equipment, information, policies, and professional staff. Persons with mobility disabilities and visual impairments have difficulty accessing various areas of fitness facilities and health clubs. AIMFREE is an important tool for increasing awareness of these accessibility barriers for people with disabilities.

  12. Disparities in mobile phone access and maternal health service utilization in Nigeria: a population-based survey.

    PubMed

    Jennings, Larissa; Omoni, Adetayo; Akerele, Akunle; Ibrahim, Yisa; Ekanem, Ekpenyong

    2015-05-01

    Mobile communication technologies may reduce maternal health disparities related to cost, distance, and infrastructure. However, the ability of mHealth initiatives to accelerate maternal health goals requires in part that women with the greatest health needs have access to mobile phones. This study examined if women with limited mobile phone access have differential odds of maternal knowledge and health service utilization as compared to female mobile phone users who are currently eligible to participate in maternal mHealth programs. Using household survey data from Nigeria, multivariable logistic regressions were used to examine the odds of maternal knowledge and service utilization by mobile phone strata. Findings showed that in settings with unequal access to mobile phones, mHealth interventions may not reach women who have the poorest maternal knowledge and care-seeking as these women often lacked mobile connectivity. As compared to mobile users, women without mobile phone access had significantly lower odds of antenatal care utilization (OR=0.48, 95%CI: 0.36-0.64), skilled delivery (OR=0.56, 95%CI: 0.45-0.70), and modern contraceptive use (OR=0.50, 95%CI: 0.33-0.76) after adjusting for demographic characteristics. They also had significantly lower knowledge of maternal danger signs (OR=0.69, 95%CI: 0.53-0.90) and knowledge of antenatal (OR=0.46, 95%CI: 0.36-0.59) and skilled delivery care benefits (OR=0.62, 95%CI: 0.47-0.82). No differences were observed by mobile phone strata in uptake of emergency obstetric care, postnatal services, or breastfeeding. As maternal mHealth strategies are increasingly utilized, more efforts are needed to improve women's access to mobile phones and minimize potential health inequities brought on by health systems and technological barriers in access to care. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

  13. Performance Analysis of Blind Subspace-Based Signature Estimation Algorithms for DS-CDMA Systems with Unknown Correlated Noise

    NASA Astrophysics Data System (ADS)

    Zarifi, Keyvan; Gershman, Alex B.

    2006-12-01

    We analyze the performance of two popular blind subspace-based signature waveform estimation techniques proposed by Wang and Poor and Buzzi and Poor for direct-sequence code division multiple-access (DS-CDMA) systems with unknown correlated noise. Using the first-order perturbation theory, analytical expressions for the mean-square error (MSE) of these algorithms are derived. We also obtain simple high SNR approximations of the MSE expressions which explicitly clarify how the performance of these techniques depends on the environmental parameters and how it is related to that of the conventional techniques that are based on the standard white noise assumption. Numerical examples further verify the consistency of the obtained analytical results with simulation results.

  14. On the performance of a code division multiple access scheme with transmit/receive conflicts

    NASA Astrophysics Data System (ADS)

    Silvester, J. A.

    One of the benefits of spread spectrum is that by assigning each user a different orthogonal signal set, multiple transmissions can occur simultaneously. This possibility is utilized in new access schemes called Code Division Multiple Access (CDMA). The present investigation is concerned with a particular CDMA implementation in which the transmit times for each symbol are exactly determined in a distributed manner such that both sender and receiver know them. In connection with a decision whether to transmit or receive, the loss of a symbol in one of the channels results. The system employs thus a coding technique which permits correct decoding of a codeword even if some constituent symbols are missing or in error. The technique used is Reed Solomon coding. The performance of this system is analyzed, and attention is given to the optimum strategy which should be used in deciding whether to receive or transmit.

  15. Accessibility of Health Clubs for People with Mobility Disabilities and Visual Impairments

    PubMed Central

    Rimmer, James H.; Riley, Barth; Wang, Edward; Rauworth, Amy

    2005-01-01

    Objective. We sought to examine the accessibility of health clubs to persons with mobility disabilities and visual impairments. Methods. We assessed 35 health clubs and fitness facilities as part of a national field trial of a new instrument, Accessibility Instruments Measuring Fitness and Recreation Environments (AIMFREE), designed to assess accessibility of fitness facilities in the following domains: (1) built environment, (2) equipment, (3) swimming pools, (4) information, (5) facility policies, and (6) professional behavior. Results. All facilities had a low to moderate level of accessibility. Some of the deficiencies concerned specific Americans with Disabilities Act guidelines pertaining to the built environment, whereas other deficiency areas were related to aspects of the facilities’ equipment, information, policies, and professional staff. Conclusions. Persons with mobility disabilities and visual impairments have difficulty accessing various areas of fitness facilities and health clubs. AIMFREE is an important tool for increasing awareness of these accessibility barriers for people with disabilities. PMID:16254234

  16. 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).

  17. 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.

  18. Mobile devices and weak ties: a study of vision impairments and workplace access in Bangalore.

    PubMed

    Pal, Joyojeet; Lakshmanan, Meera

    2015-07-01

    To explore ways in which social and economic interactions are changed by access to mobile telephony. This is a mixed-methods study of mobile phone use among 52 urban professionals with vision impairments in Bangalore, India. Interviews and survey results indicated that mobile devices, specifically those with adaptive technology software, play a vital role as multi-purpose devices that enable people with disabilities to navigate economically and socially in an environment where accessibility remains a significant challenge. We found that mobile devices play a central role in enabling and sustaining weak ties, but also that these weak ties have important gender-specific implications. We found that women have less access to weak ties than men, which impacts women's access to assistive technology (AT). This has potential implications for women's sense of safety and independence, both of which are strongly related to AT access. Implications for Rehabilitation Adaptive technologies increase individuals' ability to keep in contact with casual connections or weak ties through phone calls or social media. Men tend to have stronger access to weak ties than women in India due to cultural impediments to independent access to public spaces. Weak ties are an important source of assistive technology (AT) due to the high rate of resale of used AT, typically through informal networks.

  19. 36 CFR § 1192.95 - Mobility aid accessibility.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... mechanical, electrical or other system operates to ensure that cars do not move when the lift is in use. (3... VEHICLES 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...

  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. 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.

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

    PubMed

    Boruff, Jill T; Bilodeau, Edward

    2012-01-01

    Can a mobile optimized subject guide facilitate medical student access to mobile point-of-care tools? The guide was created at a library at a research-intensive university with six teaching hospital sites. 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. Two librarians designed a mobile optimized subject guide for medicine and conducted a survey to test its usefulness. Web analytics and survey results demonstrate that the guide is used and the students are satisfied. 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.

  3. RLS Channel Estimation with Adaptive Forgetting Factor for DS-CDMA Frequency-Domain Equalization

    NASA Astrophysics Data System (ADS)

    Kojima, Yohei; Tomeba, Hiromichi; Takeda, Kazuaki; Adachi, Fumiyuki

    Frequency-domain equalization (FDE) based on the minimum mean square error (MMSE) criterion can increase the downlink bit error rate (BER) performance of DS-CDMA beyond that possible with conventional rake combining in a frequency-selective fading channel. FDE requires accurate channel estimation. Recently, we proposed a pilot-assisted channel estimation (CE) based on the MMSE criterion. Using MMSE-CE, the channel estimation accuracy is almost insensitive to the pilot chip sequence, and a good BER performance is achieved. In this paper, we propose a channel estimation scheme using one-tap recursive least square (RLS) algorithm, where the forgetting factor is adapted to the changing channel condition by the least mean square (LMS)algorithm, for DS-CDMA with FDE. We evaluate the BER performance using RLS-CE with adaptive forgetting factor in a frequency-selective fast Rayleigh fading channel by computer simulation.

  4. 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

  5. Multiuser receiver for DS-CDMA signals in multipath channels: an enhanced multisurface method.

    PubMed

    Mahendra, Chetan; Puthusserypady, Sadasivan

    2006-11-01

    This paper deals with the problem of multiuser detection in direct-sequence code-division multiple-access (DS-CDMA) systems in multipath environments. The existing multiuser detectors can be divided into two categories: (1) low-complexity poor-performance linear detectors and (2) high-complexity good-performance nonlinear detectors. In particular, in channels where the orthogonality of the code sequences is destroyed by multipath, detectors with linear complexity perform much worse than the nonlinear detectors. In this paper, we propose an enhanced multisurface method (EMSM) for multiuser detection in multipath channels. EMSM is an intermediate piecewise linear detection scheme with a run-time complexity linear in the number of users. Its bit error rate performance is compared with existing linear detectors, a nonlinear radial basis function detector trained by the new support vector learning algorithm, and Verdu's optimal detector. Simulations in multipath channels, for both synchronous and asynchronous cases, indicate that it always outperforms all other linear detectors, performing nearly as well as nonlinear detectors.

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

    NASA Astrophysics Data System (ADS)

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

    2017-10-01

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

  7. 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.

  8. 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.

  9. Health-Promoting Nature Access for People with Mobility Impairments: A Systematic Review.

    PubMed

    Zhang, Gaochao; Poulsen, Dorthe V; Lygum, Victoria L; Corazon, Sus S; Gramkow, Marie C; Stigsdotter, Ulrika K

    2017-06-29

    This study systematically evaluated the scientific evidence for health benefits of natural environments for people with mobility impairments. Literature searches based on five categories of terms-target group, nature type, health-related impacts, nature-related activities and accessibility issues-were conducted in four databases (Web of Science, Scopus, CAB ABSTRACT and Medline). Twenty-seven articles from 4196 hits were included in the systematic reviews. We concluded that people with mobility disabilities could gain different health benefits, including physical health benefits, mental health benefits and social health benefits from nature in different kinds of nature contacts ranging from passive contact, active involvement to rehabilitative interventions. Several issues related to the accessibility and use of nature for people with mobility impairments need attention from professionals such as landscape architects, rehabilitative therapists, caregivers and policy makers. The overall quality of methodology of the included studies is not high based on assessment of the Mixed Methods Appraisal Tool (MMAT). Moreover, more randomized controlled trials and longitudinal studies that focus specifically on evidence-based health design of nature for people with mobility impairments in the future are needed.

  10. Optimal lightpath placement on a metropolitan-area network linked with optical CDMA local nets

    NASA Astrophysics Data System (ADS)

    Wang, Yih-Fuh; Huang, Jen-Fa

    2008-01-01

    A flexible optical metropolitan-area network (OMAN) [J.F. Huang, Y.F. Wang, C.Y. Yeh, Optimal configuration of OCDMA-based MAN with multimedia services, in: 23rd Biennial Symposium on Communications, Queen's University, Kingston, Canada, May 29-June 2, 2006, pp. 144-148] structured with OCDMA linkage is proposed to support multimedia services with multi-rate or various qualities of service. To prioritize transmissions in OCDMA, the orthogonal variable spreading factor (OVSF) codes widely used in wireless CDMA are adopted. In addition, for feasible multiplexing, unipolar OCDMA modulation [L. Nguyen, B. Aazhang, J.F. Young, All-optical CDMA with bipolar codes, IEEE Electron. Lett. 31 (6) (1995) 469-470] is used to generate the code selector of multi-rate OMAN, and a flexible fiber-grating-based system is used for the equipment on OCDMA-OVSF code. These enable an OMAN to assign suitable OVSF codes when creating different-rate lightpaths. How to optimally configure a multi-rate OMAN is a challenge because of displaced lightpaths. In this paper, a genetically modified genetic algorithm (GMGA) [L.R. Chen, Flexible fiber Bragg grating encoder/decoder for hybrid wavelength-time optical CDMA, IEEE Photon. Technol. Lett. 13 (11) (2001) 1233-1235] is used to preplan lightpaths in order to optimally configure an OMAN. To evaluate the performance of the GMGA, we compared it with different preplanning optimization algorithms. Simulation results revealed that the GMGA very efficiently solved the problem.

  11. An accurate evaluation of the performance of asynchronous DS-CDMA systems with zero-correlation-zone coding in Rayleigh fading

    NASA Astrophysics Data System (ADS)

    Walker, Ernest; Chen, Xinjia; Cooper, Reginald L.

    2010-04-01

    An arbitrarily accurate approach is used to determine the bit-error rate (BER) performance for generalized asynchronous DS-CDMA systems, in Gaussian noise with Raleigh fading. In this paper, and the sequel, new theoretical work has been contributed which substantially enhances existing performance analysis formulations. Major contributions include: substantial computational complexity reduction, including a priori BER accuracy bounding; an analytical approach that facilitates performance evaluation for systems with arbitrary spectral spreading distributions, with non-uniform transmission delay distributions. Using prior results, augmented by these enhancements, a generalized DS-CDMA system model is constructed and used to evaluated the BER performance, in a variety of scenarios. In this paper, the generalized system modeling was used to evaluate the performance of both Walsh- Hadamard (WH) and Walsh-Hadamard-seeded zero-correlation-zone (WH-ZCZ) coding. The selection of these codes was informed by the observation that WH codes contain N spectral spreading values (0 to N - 1), one for each code sequence; while WH-ZCZ codes contain only two spectral spreading values (N/2 - 1,N/2); where N is the sequence length in chips. Since these codes span the spectral spreading range for DS-CDMA coding, by invoking an induction argument, the generalization of the system model is sufficiently supported. The results in this paper, and the sequel, support the claim that an arbitrary accurate performance analysis for DS-CDMA systems can be evaluated over the full range of binary coding, with minimal computational complexity.

  12. Kalai-Smorodinsky bargaining solution for optimal resource allocation over wireless DS-CDMA visual sensor networks

    NASA Astrophysics Data System (ADS)

    Pandremmenou, Katerina; Kondi, Lisimachos P.; Parsopoulos, Konstantinos E.

    2012-01-01

    Surveillance applications usually require high levels of video quality, resulting in high power consumption. The existence of a well-behaved scheme to balance video quality and power consumption is crucial for the system's performance. In the present work, we adopt the game-theoretic approach of Kalai-Smorodinsky Bargaining Solution (KSBS) to deal with the problem of optimal resource allocation in a multi-node wireless visual sensor network (VSN). In our setting, the Direct Sequence Code Division Multiple Access (DS-CDMA) method is used for channel access, while a cross-layer optimization design, which employs a central processing server, accounts for the overall system efficacy through all network layers. The task assigned to the central server is the communication with the nodes and the joint determination of their transmission parameters. The KSBS is applied to non-convex utility spaces, efficiently distributing the source coding rate, channel coding rate and transmission powers among the nodes. In the underlying model, the transmission powers assume continuous values, whereas the source and channel coding rates can take only discrete values. Experimental results are reported and discussed to demonstrate the merits of KSBS over competing policies.

  13. Access Control for Mobile Assessment Systems Using ID.

    PubMed

    Nakayama, Masaharu; Ishii, Tadashi; Morino, Kazuma

    2015-01-01

    The assessment of shelters during disaster is critical to ensure the health of evacuees and prevent pandemic. In the Ishinomaki area, one of the areas most damaged by the Great East Japan Earthquake, the highly organized assessment helped to successfully manage a total of 328 shelters with a total of 46,480 evacuees. The input and analysis of vast amounts of data was tedious work for staff members. However, a web-based assessment system that utilized mobile devices was thought to decrease workload and standardize the evaluation form. The necessary access of information should be controlled in order to maintain individuals' privacy. We successfully developed an access control system using IDs. By utilizing a unique numerical ID, users can access the input form or assessment table. This avoids unnecessary queries to the server, resulting in a quick response and easy availability, even with poor internet connection.

  14. Interference Canceller Based on Cycle-and-Add Property for Single User Detection in DS-CDMA

    NASA Astrophysics Data System (ADS)

    Hettiarachchi, Ranga; Yokoyama, Mitsuo; Uehara, Hideyuki; Ohira, Takashi

    In this paper, performance of a novel interference cancellation technique for the single user detection in a direct-sequence code-division multiple access (DS-CDMA) system has been investigated. This new algorithm is based on the Cycle-and-Add property of PN (Pseudorandom Noise) sequences and can be applied for both synchronous and asynchronous systems. The proposed strategy provides a simple method that can delete interference signals one by one in spite of the power levels of interferences. Therefore, it is possible to overcome the near-far problem (NFP) in a successive manner without using transmit power control (TPC) techniques. The validity of the proposed procedure is corroborated by computer simulations in additive white Gaussian noise (AWGN) and frequency-nonselective fading channels. Performance results indicate that the proposed receiver outperforms the conventional receiver and, in many cases, it does so with a considerable gain.

  15. 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

  16. Public Safety Broadband Network Architecture Description

    DTIC Science & Technology

    2013-08-01

    could be used to add an in-app purchase to the user’s mobile phone bill. Major operators , such as AT& T , Deutsche Telekom, Orange, Telefonica and...3GPP technologies such as CDMA2000 and WiMAX networks. MME Mobility Managemen t Entity The MME is the key control-node for the LTE access-network... operator ( operator -managed small cells, etc.) or provides sufficient security (authentication, encryption, etc.). See Figure D3. Figure D3: ITU- T

  17. 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.

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

    PubMed Central

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

    2016-01-01

    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. PMID:28005473

  19. Crew Access Arm Installation onto Mobile Launcher

    NASA Image and Video Library

    2018-02-26

    With a control panel visible in the foreground, a technician begins installation of the Orion crew access arm (CAA) to the mobile launcher (ML) tower at NASA's Kennedy Space Center in Florida. NASA's Exploration Ground Systems organization has been overseeing installation of umbilicals and other launch accessories on the 380-foot-tall ML in preparation for stacking the first launch of the Space launch System, or SLS, rocket with an Orion spacecraft. The CAA is designed to rotate from its retracted position and line up with Orion's crew hatch providing entry for astronauts and technicians.

  20. Crew Access Arm Installation onto Mobile Launcher

    NASA Image and Video Library

    2018-02-26

    Viewed from the 274-foot level mobile launcher (ML), technicians help install the Orion crew access arm (CAA) to the tower at NASA's Kennedy Space Center in Florida. NASA's Exploration Ground Systems organization has been overseeing installation of umbilicals and other launch accessories on the 380-foot-tall ML in preparation for stacking the first launch of the Space launch System (SLS), rocket with an Orion spacecraft. The CAA is designed to rotate from its retracted position and line up with Orion's crew hatch providing entry for astronauts and technicians.

  1. Space-time adaptive decision feedback neural receivers with data selection for high-data-rate users in DS-CDMA systems.

    PubMed

    de Lamare, Rodrigo C; Sampaio-Neto, Raimundo

    2008-11-01

    A space-time adaptive decision feedback (DF) receiver using recurrent neural networks (RNNs) is proposed for joint equalization and interference suppression in direct-sequence code-division multiple-access (DS-CDMA) systems equipped with antenna arrays. The proposed receiver structure employs dynamically driven RNNs in the feedforward section for equalization and multiaccess interference (MAI) suppression and a finite impulse response (FIR) linear filter in the feedback section for performing interference cancellation. A data selective gradient algorithm, based upon the set-membership (SM) design framework, is proposed for the estimation of the coefficients of RNN structures and is applied to the estimation of the parameters of the proposed neural receiver structure. Simulation results show that the proposed techniques achieve significant performance gains over existing schemes.

  2. Health-Promoting Nature Access for People with Mobility Impairments: A Systematic Review

    PubMed Central

    Zhang, Gaochao; Poulsen, Dorthe V.; Lygum, Victoria L.; Corazon, Sus S.; Gramkow, Marie C.; Stigsdotter, Ulrika K.

    2017-01-01

    This study systematically evaluated the scientific evidence for health benefits of natural environments for people with mobility impairments. Literature searches based on five categories of terms—target group, nature type, health-related impacts, nature-related activities and accessibility issues—were conducted in four databases (Web of Science, Scopus, CAB ABSTRACT and Medline). Twenty-seven articles from 4196 hits were included in the systematic reviews. We concluded that people with mobility disabilities could gain different health benefits, including physical health benefits, mental health benefits and social health benefits from nature in different kinds of nature contacts ranging from passive contact, active involvement to rehabilitative interventions. Several issues related to the accessibility and use of nature for people with mobility impairments need attention from professionals such as landscape architects, rehabilitative therapists, caregivers and policy makers. The overall quality of methodology of the included studies is not high based on assessment of the Mixed Methods Appraisal Tool (MMAT). Moreover, more randomized controlled trials and longitudinal studies that focus specifically on evidence-based health design of nature for people with mobility impairments in the future are needed. PMID:28661433

  3. 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.

  4. 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.

  5. Quantifying the Impact of Accessibility on Preventive Healthcare in Sub-Saharan Africa Using Mobile Phone Data

    PubMed Central

    Wesolowski, Amy; O’Meara, Wendy Prudhomme; Tatem, Andrew J.; Ndege, Samson; Eagle, Nathan

    2015-01-01

    Background: Poor physical access to health facilities has been identified as an important contributor to reduced uptake of preventive health services and is likely to be most critical in low-income settings. However, the relation among physical access, travel behavior, and the uptake of healthcare is difficult to quantify. Methods: Using anonymized mobile phone data from 2008 to 2009, we analyze individual and spatially aggregated travel patterns of 14,816,521 subscribers across Kenya and compare these measures to (1) estimated travel times to health facilities and (2) data on the uptake of 2 preventive healthcare interventions in an area of western Kenya: childhood immunizations and antenatal care. Results: We document that long travel times to health facilities are strongly correlated with increased mobility in geographically isolated areas. Furthermore, we found that in areas with equal physical access to healthcare, mobile phone-derived measures of mobility predict which regions are lacking preventive care. Conclusions: Routinely collected mobile phone data provide a simple and low-cost approach to mapping the uptake of preventive healthcare in low-income settings. PMID:25643101

  6. Quantifying the impact of accessibility on preventive healthcare in sub-Saharan Africa using mobile phone data.

    PubMed

    Wesolowski, Amy; O'Meara, Wendy Prudhomme; Tatem, Andrew J; Ndege, Samson; Eagle, Nathan; Buckee, Caroline O

    2015-03-01

    Poor physical access to health facilities has been identified as an important contributor to reduced uptake of preventive health services and is likely to be most critical in low-income settings. However, the relation among physical access, travel behavior, and the uptake of healthcare is difficult to quantify. Using anonymized mobile phone data from 2008 to 2009, we analyze individual and spatially aggregated travel patterns of 14,816,521 subscribers across Kenya and compare these measures to (1) estimated travel times to health facilities and (2) data on the uptake of 2 preventive healthcare interventions in an area of western Kenya: childhood immunizations and antenatal care. We document that long travel times to health facilities are strongly correlated with increased mobility in geographically isolated areas. Furthermore, we found that in areas with equal physical access to healthcare, mobile phone-derived measures of mobility predict which regions are lacking preventive care. Routinely collected mobile phone data provide a simple and low-cost approach to mapping the uptake of preventive healthcare in low-income settings.

  7. 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

  8. 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…

  9. 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…

  10. The possible effects of health professional mobility on access to care for patients.

    PubMed

    Glinos, Irene A

    2014-01-01

    The chapter explains how health professional mobility impacts on the resources and capacity available within a health system, and how this affects service delivery and access. The contrasting experiences of destination countries, which receive foreign inflows of health professionals, and of source countries, which loose workforce due to outflows, are illustrated with country examples. The evidence opens the debate on how EU countries compete for health workforce, what this means for resource-strained, crisis-hit Member States, and whether there is any room for intra-European solidarity. The nexus between patient mobility and health professional mobility is moreover highlighted. This take on free mobility in the EU has received little attention, and while evidence is scarce, it calls for careful analysis when considering the possible effects of free movement on access to care in national health systems. The chapter reformulates the question on 'who wins' and 'who looses' from freedom of movement in the EU to turn our attention away from those who go abroad for care and instead focus on those who stay at home.

  11. Improving Evidence Dissemination and Accessibility through a Mobile-based Resource Platform.

    PubMed

    Zhu, Zheng; Xing, Weijie; Hu, Yan; Zhou, Yingfeng; Gu, Ying

    2018-05-28

    Current mobile information technologies fundamentally influence evidence dissemination from the perspective of both evidence seekers and evidence providers. However, there is no related study which tried using a mobile-based platform to disseminate evidence in China. The main object of this study is to develop a mobile-based evidence resource platform and to evaluate its effects of improving nurses' access to evidence-based practice resources and meeting users' demands. The mobile-based evidence resource platform was developed in 2014. A cross-sectional study was conducted over a period of 2 months between December 2015 and January 2016 to evaluate user experiences of and preferences regarding the platform. Descriptive analysis was adopted to analyze information and its communication effects from December 2014 to March 2017. A total of 472 participants met the inclusion criteria and responded to the survey. High scores were received for the overall rating (4.34 ± 0.67), evidence section (4.30 ± 0.63), learning materials section (4.26 ± 0.65), news section (4.27 ± 0.66), readability (4.38 ± 0.63), design and structure (4.38 ± 0.63), and interactivity (3.58 ± 0.84). As of March 31, 2017, the total number of followers was 28,954. The total number of readings was 584,834. The most current WCI value was 388.72. Our study demonstrated that the mobile-based platform for evidence transfer can promote the accessibility of evidence and meet users' demands. This mobile-based platform is currently available in the WeChat application environment. It will be a wise option for healthcare professionals for the purposes of learning about EBP and disseminating evidence in China.

  12. Accessible transportation technologies research initiative : advancing mobility solutions for travelers with disabilities.

    DOT National Transportation Integrated Search

    2016-01-01

    The Accessible Transportation Technologies Research Initiative (ATTRI) improves the mobility of travelers with disabilities through research, development, and implementation of transformative technologies, applications, or systems for people of all a...

  13. Crew Access Arm Installation onto Mobile Launcher

    NASA Image and Video Library

    2018-02-26

    Viewed from the 274-foot level mobile launcher (ML), the Orion crew access arm (CAA) is beign installed on the tower. The CAA will support the Space launch System (SLS) rocket at NASA's Kennedy Space Center in Florida. NASA's Exploration Ground Systems organization has been overseeing installation of umbilicals and other launch accessories on the 380-foot-tall ML in preparation for stacking the first launch of the Space launch System, or SLS, rocket with an Orion spacecraft. The CAA is designed to rotate from its retracted position and line up with Orion's crew hatch providing entry for astronauts and technicians.

  14. Crew Access Arm Installation onto Mobile Launcher

    NASA Image and Video Library

    2018-02-26

    Viewed from the 274-foot level mobile launcher (ML), a technician begins installation of the Orion crew access arm (CAA) to the tower. The CAA will support the Space launch System (SLS) rocket at NASA's Kennedy Space Center in Florida. NASA's Exploration Ground Systems organization has been overseeing installation of umbilicals and other launch accessories on the 380-foot-tall ML in preparation for stacking the first launch of the Space launch System, or SLS, rocket with an Orion spacecraft. The CAA is designed to rotate from its retracted position and line up with Orion's crew hatch providing entry for astronauts and technicians.

  15. Crew Access Arm Installation onto Mobile Launcher

    NASA Image and Video Library

    2018-02-26

    Viewed from the 274-foot level mobile launcher (ML), a crane positions the Orion crew access arm (CAA) so it can be attached to the tower that will support the Space launch System (SLS) rocket at NASA's Kennedy Space Center in Florida. NASA's Exploration Ground Systems organization has been overseeing installation of umbilicals and other launch accessories on the 380-foot-tall ML in preparation for stacking the first launch of the SLS, rocket with an Orion spacecraft. The CAA is designed to rotate from its retracted position and line up with Orion's crew hatch providing entry for astronauts and technicians.

  16. Crew Access Arm Installation onto Mobile Launcher

    NASA Image and Video Library

    2018-02-24

    At NASA's Kennedy Space Center in Florida, the Orion crew access arm (CAA) is lifted and attached to the Mobile Launcher (ML). The arm is installed at about the 274-foot level on the ML tower. NASA's Exploration Ground Systems organization has been overseeing installation of umbilicals and other launch accessories on the 380-foot-tall ML in preparation for stacking the first launch of the Space launch System (SLS), rocket with an Orion spacecraft. The CAA is designed to rotate from its retracted position and line up with Orion's crew hatch providing entry for astronauts and technicians.

  17. Crew Access Arm Install on Mobile Launcher

    NASA Image and Video Library

    2018-02-24

    At NASA's Kennedy Space Center in Florida, the Orion crew access arm (CAA) is lifted and attached to the Mobile Launcher (ML). The arm is installed at about the 274-foot level on the ML tower. NASA's Exploration Ground Systems organization has been overseeing installation of umbilicals and other launch accessories on the 380-foot-tall ML in preparation for stacking the first launch of the Space launch System (SLS), rocket with an Orion spacecraft. The CAA is designed to rotate from its retracted position and line up with Orion's crew hatch providing entry for astronauts and technicians.

  18. Crew Access Arm Installation onto Mobile Launcher

    NASA Image and Video Library

    2018-02-26

    At NASA's Kennedy Space Center in Florida, a crane positions the Orion crew access arm (CAA) so it can be attached to the mobile launcher (ML). The arm will be installed at about the 274-foot level on the ML tower. NASA's Exploration Ground Systems organization has been overseeing installation of umbilicals and other launch accessories on the 380-foot-tall ML in preparation for stacking the first launch of the Space launch System (SLS), rocket with an Orion spacecraft. The CAA is designed to rotate from its retracted position and line up with Orion's crew hatch providing entry for astronauts and technicians.

  19. Crew Access Arm Installation onto Mobile Launcher

    NASA Image and Video Library

    2018-02-26

    At NASA's Kennedy Space Center in Florida, a crane lifts the Orion crew access arm (CAA) so it can be attached to the mobile launcher (ML). The arm will be installed at about the 274-foot level on the ML tower. NASA's Exploration Ground Systems organization has been overseeing installation of umbilicals and other launch accessories on the 380-foot-tall ML in preparation for stacking the first launch of the Space launch System (SLS), rocket with an Orion spacecraft. The CAA is designed to rotate from its retracted position and line up with Orion's crew hatch providing entry for astronauts and technicians.

  20. Performance Analysis of New Binary User Codes for DS-CDMA Communication

    NASA Astrophysics Data System (ADS)

    Usha, Kamle; Jaya Sankar, Kottareddygari

    2016-03-01

    This paper analyzes new binary spreading codes through correlation properties and also presents their performance over additive white Gaussian noise (AWGN) channel. The proposed codes are constructed using gray and inverse gray codes. In this paper, a n-bit gray code appended by its n-bit inverse gray code to construct the 2n-length binary user codes are discussed. Like Walsh codes, these binary user codes are available in sizes of power of two and additionally code sets of length 6 and their even multiples are also available. The simple construction technique and generation of code sets of different sizes are the salient features of the proposed codes. Walsh codes and gold codes are considered for comparison in this paper as these are popularly used for synchronous and asynchronous multi user communications respectively. In the current work the auto and cross correlation properties of the proposed codes are compared with those of Walsh codes and gold codes. Performance of the proposed binary user codes for both synchronous and asynchronous direct sequence CDMA communication over AWGN channel is also discussed in this paper. The proposed binary user codes are found to be suitable for both synchronous and asynchronous DS-CDMA communication.

  1. 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... RULES RELATING TO COMMON CARRIERS Procedures for Handling Priority Services in Emergencies § 64.402 Policies and procedures for the provision of priority access service by commercial mobile radio service...

  2. 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).

  3. Rural patients' access to mobile phones and willingness to receive mobile phone-based pharmacy and other health technology services: a pilot study.

    PubMed

    Sankaranarayanan, Jayashri; Sallach, Rory E

    2014-02-01

    This pilot study explores the patient-centered demand for mobile phone-based health (mobile health [m-health]) services in the rural United States by documenting rural patients' access to mobile phones and patients' willingness to receive m-health services. An anonymous institutional review board-approved survey was completed by patients visiting two rural pharmacies in Nebraska from August to October 2011. Patients who volunteered to complete the survey provided their demographic data, disease state information, health status, mobile phone access, and willingness to receive (in terms of using and giving time to) m-health services. The majority of the 24 survey respondents were 19-40 years old (52%), female (88%), married (63%), with excellent to very good health status (63%), with no comorbidities (83%), with ≤$100 monthly medication expenses (80%), with private insurance (78%), living within 5 miles of their pharmacy (71%), and reporting that m-health services are important to them (75%; 12/16). Approximately 95%, 81%, 73%, and 55% of respondents reported access to a mobile phone, voice mails, text messaging, and mobile phone applications, respectively. Of the respondents, 65%, 57%, 52%, and 48% were willing to receive prerecorded messages for appointment reminders from the doctor, disease information, medication use/self-care information, and symptom monitoring information, respectively. In total, 70%, 63%, 61%, 54%, and 50% were willing to receive prerecorded messages from the pharmacist containing contact requests, new/refill prescription reminders, information on medication problems, reviewing/monitoring of medication use, and medication self-management/preventive screenings/immunizations, respectively. Of 44% (7/16) respondents willing to give time for m-health services, 83% were willing to give 15 min, and 17% were willing to give 30 min every month. By demonstrating rural patients' demand for m-health (including pharmacy) services, this is one of the

  4. 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.

  5. Mobile Launcher Crew Access Arm Transport from Cocoa FL to KSC

    NASA Image and Video Library

    2017-10-17

    The Orion crew access arm departs Precision Fabricating and Cleaning in Cocoa, Florida, atop a flatbed truck. The access arm will be transported to a storage location at NASA's Kennedy Space Center in Florida. Later this month, the arm will be transported to the mobile launcher (ML) tower at the center. The crew access arm will be located at about the 274-foot level on the tower. It will rotate from its retracted position and interface with the Orion crew hatch location to provide entry to the Orion crew module. The Ground Systems Development and Operations Program is overseeing installation of umbilicals and launch accessories on the ML tower.

  6. Mobile Launcher Crew Access Arm Transport from Cocoa FL to KSC

    NASA Image and Video Library

    2017-10-17

    A flatbed truck with the Orion crew access arm secured atop arrives in a storage location at NASA's Kennedy Space Center in Florida. The access arm was transported from Precision Fabricating and Cleaning in Cocoa, Florida. Later this month, the arm will be transported to the mobile launcher (ML) tower at the center. The crew access arm will be located at about the 274-foot level on the tower. It will rotate from its retracted position and interface with the Orion crew hatch location to provide entry to the Orion crew module. The Ground Systems Development and Operations Program is overseeing installation of umbilicals and launch accessories on the ML tower.

  7. Crew Access Arm Installation onto Mobile Launcher

    NASA Image and Video Library

    2018-02-24

    At NASA's Kennedy Space Center in Florida, a crane is prepared to lift the Orion crew access arm (CAA) so it can be attached to the mobile launcher (ML). The arm will be installed at about the 274-foot level on the ML tower. NASA's Exploration Ground Systems organization has been overseeing installation of umbilicals and other launch accessories on the 380-foot-tall ML in preparation for stacking the first launch of the Space launch System, or SLS, rocket with an Orion spacecraft. The CAA is designed to rotate from its retracted position and line up with Orion's crew hatch providing entry for astronauts and technicians.

  8. Crew Access Arm Installation onto Mobile Launcher

    NASA Image and Video Library

    2018-02-26

    At NASA's Kennedy Space Center in Florida, technicians assist as a crane lifts the Orion crew access arm (CAA) so it can be attached to the mobile launcher (ML). The arm will be installed at about the 274-foot level on the ML tower. NASA's Exploration Ground Systems organization has been overseeing installation of umbilicals and other launch accessories on the 380-foot-tall ML in preparation for stacking the first launch of the Space launch System (SLS), rocket with an Orion spacecraft. The CAA is designed to rotate from its retracted position and line up with Orion's crew hatch providing entry for astronauts and technicians.

  9. Crew Access Arm Installation onto Mobile Launcher

    NASA Image and Video Library

    2018-02-26

    At NASA's Kennedy Space Center in Florida, a crane begins lifting the Orion crew access arm (CAA) so it can be attached to the mobile launcher (ML). The arm will be installed at about the 274-foot level on the ML tower. NASA's Exploration Ground Systems organization has been overseeing installation of umbilicals and other launch accessories on the 380-foot-tall ML in preparation for stacking the first launch of the Space launch System (SLS), rocket with an Orion spacecraft. The CAA is designed to rotate from its retracted position and line up with Orion's crew hatch providing entry for astronauts and technicians.

  10. Accessing care summaries at point-of-care:Implementation of mobile devices for personal carers in aged care.

    PubMed

    Brimelow, Rachel E; Gibney, Annie; Meakin, Suzanne; Wollin, Judy A

    2017-04-01

    Continued development of mobile technology now allows access to information at the point-of-care. This study was conducted to evaluate the use of one such tool on a mobile device, from the carer perspective. Caregivers across 12 aged-care facilities were supplied mobile devices to access a Picture Care Plan (PCP), a specific tool designed around the role of the personal carer. An anonymous questionnaire was subsequently completed by 85 carers with questions relating to participants' experience. Perceived helpfulness of the PCP at the point-of-care was high (87%). A significant number of participants believed the use of the PCP increased resident safety and quality of care (76%). Practical components related to the carrying of the device, network speed and the requirement to maintain communication with senior members of staff to ascertain updates were also expressed by participants. Findings suggest that staff are receptive to adoption of mobile devices to access care directives at the point-of-care and that the technology is useful.

  11. 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.

  12. 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.

  13. Improving the Accessibility of Mobile OCR Apps Via Interactive Modalities.

    PubMed

    Cutter, Michael; Manduchi, Roberto

    2017-10-01

    Mobile optical character recognition (OCR) apps have come of age. Many blind individuals use them on a daily basis. The usability of such tools, however, is limited by the requirement that a good picture of the text to be read must be taken, something that is difficult to do without sight. Some mobile OCR apps already implement auto-shot and guidance mechanisms to facilitate this task. In this paper, we describe two experiments with blind participants, who tested these two interactive mechanisms on a customized iPhone implementation. These experiments bring to light a number of interesting aspects of accessing a printed document without sight, and enable a comparative analysis of the available interaction modalities.

  14. Improving the Accessibility of Mobile OCR Apps Via Interactive Modalities

    PubMed Central

    Cutter, Michael; Manduchi, Roberto

    2017-01-01

    Mobile optical character recognition (OCR) apps have come of age. Many blind individuals use them on a daily basis. The usability of such tools, however, is limited by the requirement that a good picture of the text to be read must be taken, something that is difficult to do without sight. Some mobile OCR apps already implement auto-shot and guidance mechanisms to facilitate this task. In this paper, we describe two experiments with blind participants, who tested these two interactive mechanisms on a customized iPhone implementation. These experiments bring to light a number of interesting aspects of accessing a printed document without sight, and enable a comparative analysis of the available interaction modalities. PMID:29270243

  15. Mobile Launcher Crew Access Arm Transport from Cocoa FL to KSC

    NASA Image and Video Library

    2017-10-17

    Two heavy-lift cranes are used to lower the Orion crew access arm onto a work stand in a storage location at NASA's Kennedy Space Center in Florida. The access arm was transported from Precision Fabricating and Cleaning in Cocoa, Florida. Later this month, the arm will be transported to the mobile launcher (ML) tower at the center. The crew access arm will be located at about the 274-foot level on the tower. It will rotate from its retracted position and interface with the Orion crew hatch location to provide entry to the Orion crew module. The Ground Systems Development and Operations Program is overseeing installation of umbilicals and launch accessories on the ML tower.

  16. Mobile Launcher Crew Access Arm Prep for Transport to Kennedy Sp

    NASA Image and Video Library

    2017-10-16

    The Orion crew access arm is being secured on a flatbed truck at Precision Fabricating and Cleaning in Cocoa, Florida. The crew access arm will be transported to a storage location near NASA's Kennedy Space Center in Florida. Later this month, the arm will be transported to the mobile launcher (ML) tower at the center. The crew access arm will be located at about the 274-foot level on the tower. It will rotate from its retracted position and interface with the Orion crew hatch location to provide entry to the Orion crew module. The Ground Systems Development and Operations Program is overseeing installation of umbilicals and launch accessories on the ML tower.

  17. Mobile Launcher Crew Access Arm Prep for Transport to Kennedy Sp

    NASA Image and Video Library

    2017-10-16

    Two heavy-lift cranes are used to lower the Orion crew access arm onto a flatbed truck at Precision Fabricating and Cleaning in Cocoa, Florida. The crew access arm will be transported to a storage location near NASA's Kennedy Space Center in Florida. Later this month, the arm will be transported to the mobile launcher (ML) tower at the center. The crew access arm will be located at about the 274-foot level on the tower. It will rotate from its retracted position and interface with the Orion crew hatch location to provide entry to the Orion crew module. The Ground Systems Development and Operations Program is overseeing installation of umbilicals and launch accessories on the ML tower.

  18. Mobile Launcher Crew Access Arm Prep for Transport to Kennedy Sp

    NASA Image and Video Library

    2017-10-16

    The Orion crew access arm is being secured onto a flatbed truck at Precision Fabricating and Cleaning in Cocoa, Florida. The crew access arm will be transported to a storage location near NASA's Kennedy Space Center in Florida. Later this month, the arm will be transported to the mobile launcher (ML) tower at the center. The crew access arm will be located at about the 274-foot level on the tower. It will rotate from its retracted position and interface with the Orion crew hatch location to provide entry to the Orion crew module. The Ground Systems Development and Operations Program is overseeing installation of umbilicals and launch accessories on the ML tower.

  19. Mobile Launcher Crew Access Arm Prep for Transport to Kennedy Sp

    NASA Image and Video Library

    2017-10-16

    The Orion crew access arm is secured on a flatbed truck at Precision Fabricating and Cleaning in Cocoa, Florida. The crew access arm will be transported to a storage location near NASA's Kennedy Space Center in Florida. Later this month, the arm will be transported to the mobile launcher (ML) tower at the center. The crew access arm will be located at about the 274-foot level on the tower. It will rotate from its retracted position and interface with the Orion crew hatch location to provide entry to the Orion crew module. The Ground Systems Development and Operations Program is overseeing installation of umbilicals and launch accessories on the ML tower.

  20. Mobile Launcher Crew Access Arm Prep for Transport to Kennedy Sp

    NASA Image and Video Library

    2017-10-16

    The Orion crew access arm is being moved by crane onto a flatbed truck at Precision Fabricating and Cleaning in Cocoa, Florida. The crew access arm will be transported to a storage location near NASA's Kennedy Space Center in Florida. Later this month, the arm will be transported to the mobile launcher (ML) tower at the center. The crew access arm will be located at about the 274-foot level on the tower. It will rotate from its retracted position and interface with the Orion crew hatch location to provide entry to the Orion crew module. The Ground Systems Development and Operations Program is overseeing installation of umbilicals and launch accessories on the ML tower.

  1. Mobile Launcher Crew Access Arm Transport from Cocoa FL to KSC

    NASA Image and Video Library

    2017-10-17

    A flatbed truck with the Orion crew access arm secured atop travels along a road in Cocoa, Florida, after departing Precision Fabricating and Cleaning. The access arm will be transported to a storage location at NASA's Kennedy Space Center in Florida. Later this month, the arm will be transported to the mobile launcher (ML) tower at the center. The crew access arm will be located at about the 274-foot level on the tower. It will rotate from its retracted position and interface with the Orion crew hatch location to provide entry to the Orion crew module. The Ground Systems Development and Operations Program is overseeing installation of umbilicals and launch accessories on the ML tower.

  2. Mobile Launcher Crew Access Arm Transport from Cocoa FL to KSC

    NASA Image and Video Library

    2017-10-17

    Two heavy-lift cranes lower the Orion crew access arm onto a work stand in a storage location at NASA's Kennedy Space Center in Florida. The access arm was transported from Precision Fabricating and Cleaning in Cocoa, Florida. Later this month, the arm will be transported to the mobile launcher (ML) tower at the center. The crew access arm will be located at about the 274-foot level on the tower. It will rotate from its retracted position and interface with the Orion crew hatch location to provide entry to the Orion crew module. The Ground Systems Development and Operations Program is overseeing installation of umbilicals and launch accessories on the ML tower.

  3. Mobile Launcher Crew Access Arm Transport from Cocoa FL to KSC

    NASA Image and Video Library

    2017-10-17

    Two heavy-lift cranes are used to tilt and lower the Orion crew access arm onto a work stand in a storage location at NASA's Kennedy Space Center in Florida. The access arm was transported from Precision Fabricating and Cleaning in Cocoa, Florida. Later this month, the arm will be transported to the mobile launcher (ML) tower at the center. The crew access arm will be located at about the 274-foot level on the tower. It will rotate from its retracted position and interface with the Orion crew hatch location to provide entry to the Orion crew module. The Ground Systems Development and Operations Program is overseeing installation of umbilicals and launch accessories on the ML tower.

  4. Mobile Launcher Crew Access Arm Prep for Transport to Kennedy Sp

    NASA Image and Video Library

    2017-10-16

    Two heavy-lift cranes are being used to lower the Orion crew access arm onto a flatbed truck at Precision Fabricating and Cleaning in Cocoa, Florida. The crew access arm will be transported to a storage location near NASA's Kennedy Space Center in Florida. Later this month, the arm will be transported to the mobile launcher (ML) tower at the center. The crew access arm will be located at about the 274-foot level on the tower. It will rotate from its retracted position and interface with the Orion crew hatch location to provide entry to the Orion crew module. The Ground Systems Development and Operations Program is overseeing installation of umbilicals and launch accessories on the ML tower.

  5. Mobile Launcher Crew Access Arm Transport from Cocoa FL to KSC

    NASA Image and Video Library

    2017-10-17

    Two heavy-lift cranes are used to lift the Orion crew access arm up from a flatbed truck in a storage location at NASA's Kennedy Space Center in Florida. The access arm was transported from Precision Fabricating and Cleaning in Cocoa, Florida. Later this month, the arm will be transported to the mobile launcher (ML) tower at the center. The crew access arm will be located at about the 274-foot level on the tower. It will rotate from its retracted position and interface with the Orion crew hatch location to provide entry to the Orion crew module. The Ground Systems Development and Operations Program is overseeing installation of umbilicals and launch accessories on the ML tower.

  6. Collaborative Indoor Access Point Localization Using Autonomous Mobile Robot Swarm

    PubMed Central

    Awad, Fahed; Naserllah, Muhammad; Omar, Ammar; Abu-Hantash, Alaa; Al-Taj, Abrar

    2018-01-01

    Localization of access points has become an important research problem due to the wide range of applications it addresses such as dismantling critical security threats caused by rogue access points or optimizing wireless coverage of access points within a service area. Existing proposed solutions have mostly relied on theoretical hypotheses or computer simulation to demonstrate the efficiency of their methods. The techniques that rely on estimating the distance using samples of the received signal strength usually assume prior knowledge of the signal propagation characteristics of the indoor environment in hand and tend to take a relatively large number of uniformly distributed random samples. This paper presents an efficient and practical collaborative approach to detect the location of an access point in an indoor environment without any prior knowledge of the environment. The proposed approach comprises a swarm of wirelessly connected mobile robots that collaboratively and autonomously collect a relatively small number of non-uniformly distributed random samples of the access point’s received signal strength. These samples are used to efficiently and accurately estimate the location of the access point. The experimental testing verified that the proposed approach can identify the location of the access point in an accurate and efficient manner. PMID:29385042

  7. Collaborative Indoor Access Point Localization Using Autonomous Mobile Robot Swarm.

    PubMed

    Awad, Fahed; Naserllah, Muhammad; Omar, Ammar; Abu-Hantash, Alaa; Al-Taj, Abrar

    2018-01-31

    Localization of access points has become an important research problem due to the wide range of applications it addresses such as dismantling critical security threats caused by rogue access points or optimizing wireless coverage of access points within a service area. Existing proposed solutions have mostly relied on theoretical hypotheses or computer simulation to demonstrate the efficiency of their methods. The techniques that rely on estimating the distance using samples of the received signal strength usually assume prior knowledge of the signal propagation characteristics of the indoor environment in hand and tend to take a relatively large number of uniformly distributed random samples. This paper presents an efficient and practical collaborative approach to detect the location of an access point in an indoor environment without any prior knowledge of the environment. The proposed approach comprises a swarm of wirelessly connected mobile robots that collaboratively and autonomously collect a relatively small number of non-uniformly distributed random samples of the access point's received signal strength. These samples are used to efficiently and accurately estimate the location of the access point. The experimental testing verified that the proposed approach can identify the location of the access point in an accurate and efficient manner.

  8. Crew Access Arm Installation onto Mobile Launcher

    NASA Image and Video Library

    2018-02-24

    Under the watchful eye of technicians and engineers, a crane is prepared to lift the Orion crew access arm (CAA) so it can be attached to the mobile launcher (ML) at NASA's Kennedy Space Center in Florida. The arm will be installed at about the 274-foot level on the ML tower. NASA's Exploration Ground Systems organization has been overseeing installation of umbilicals and other launch accessories on the 380-foot-tall ML in preparation for stacking the first launch of the Space launch System, or SLS, rocket with an Orion spacecraft. The CAA is designed to rotate from its retracted position and line up with Orion's crew hatch providing entry for astronauts and technicians.

  9. Crew Access Arm Installation onto Mobile Launcher

    NASA Image and Video Library

    2018-02-26

    Under the watchful eye of technicians and engineers, a crane begins lifting the Orion crew access arm (CAA) so it can be attached to the mobile launcher (ML) at NASA's Kennedy Space Center in Florida. The arm will be installed at about the 274-foot level on the ML tower. NASA's Exploration Ground Systems organization has been overseeing installation of umbilicals and other launch accessories on the 380-foot-tall ML in preparation for stacking the first launch of the Space launch System (SLS), rocket with an Orion spacecraft. The CAA is designed to rotate from its retracted position and line up with Orion's crew hatch providing entry for astronauts and technicians.

  10. Crew Access Arm Installation onto Mobile Launcher

    NASA Image and Video Library

    2018-02-26

    Seen to the right of the iconic Vehicle Assembly Building at NASA's Kennedy Space Center in Florida, a crane positions the Orion crew access arm (CAA) so it can be attached to the mobile launcher (ML). The arm will be installed at about the 274-foot level on the ML tower. NASA's Exploration Ground Systems organization has been overseeing installation of umbilicals and other launch accessories on the 380-foot-tall ML in preparation for stacking the first launch of the Space launch System (SLS), rocket with an Orion spacecraft. The CAA is designed to rotate from its retracted position and line up with Orion's crew hatch providing entry for astronauts and technicians.

  11. Broadband and scalable mobile satellite communication system for future access networks

    NASA Astrophysics Data System (ADS)

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

    2005-07-01

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

  12. Literacy disparities in patient access and health-related use of Internet and mobile technologies.

    PubMed

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

    2015-12-01

    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. 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. A secondary analysis utilizing data from 1077 primary care patients enrolled in two, multisite studies from 2011-2013. Patients were administered an in-person, structured interview. Patients with adequate health literacy were more likely to own a mobile phone or smartphone in comparison with patients having marginal or low literacy (mobile phone ownership: 96.8 vs. 95.2 vs. 90.1%, respectively, P < 0.001; smartphone ownership: 70.6 vs. 62.5 vs. 40.1%, P < 0.001) and to report text messaging (78.6 vs. 75.2 vs. 53.1%, P < 0.001). They were also more likely to have access to the Internet from their home (92.1 vs. 74.7 vs. 44.9%, P < 0.001) and to report using the Internet for email (93.0 vs. 75.7 vs. 38.5%, P < 0.001), browsing the web (93.9 vs. 80.2 vs. 44.5%, P < 0.001), accessing health information (86.3 vs. 75.5 vs. 40.8%, P < 0.001), and communicating with providers (54.2 vs. 29.8 vs. 13.0%, P < 0.001). Relationships remained significant in multivariable analyses controlling for relevant covariates. 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. © 2014 John Wiley & Sons Ltd.

  13. Internet Use and Access Among Pregnant Women via Computer and Mobile Phone: Implications for Delivery of Perinatal Care.

    PubMed

    Peragallo Urrutia, Rachel; Berger, Alexander A; Ivins, Amber A; Beckham, A Jenna; Thorp, John M; Nicholson, Wanda K

    2015-03-30

    The use of Internet-based behavioral programs may be an efficient, flexible method to enhance prenatal care and improve pregnancy outcomes. There are few data about access to, and use of, the Internet via computers and mobile phones among pregnant women. We describe pregnant women's access to, and use of, computers, mobile phones, and computer technologies (eg, Internet, blogs, chat rooms) in a southern United States population. We describe the willingness of pregnant women to participate in Internet-supported weight-loss interventions delivered via computers or mobile phones. We conducted a cross-sectional survey among 100 pregnant women at a tertiary referral center ultrasound clinic in the southeast United States. Data were analyzed using Stata version 10 (StataCorp) and R (R Core Team 2013). Means and frequency procedures were used to describe demographic characteristics, access to computers and mobile phones, and use of specific Internet modalities. Chi-square testing was used to determine whether there were differences in technology access and Internet modality use according to age, race/ethnicity, income, or children in the home. The Fisher's exact test was used to describe preferences to participate in Internet-based postpartum weight-loss interventions via computer versus mobile phone. Logistic regression was used to determine demographic characteristics associated with these preferences. The study sample was 61.0% white, 26.0% black, 6.0% Hispanic, and 7.0% Asian with a mean age of 31.0 (SD 5.1). Most participants had access to a computer (89/100, 89.0%) or mobile phone (88/100, 88.0%) for at least 8 hours per week. Access remained high (>74%) across age groups, racial/ethnic groups, income levels, and number of children in the home. Internet/Web (94/100, 94.0%), email (90/100, 90.0%), and Facebook (50/100, 50.0%) were the most commonly used Internet technologies. Women aged less than 30 years were more likely to report use of Twitter and chat rooms

  14. Mobile Launcher Crew Access Arm Prep for Transport to Kennedy Sp

    NASA Image and Video Library

    2017-10-16

    Two heavy-lift cranes are being used to move the Orion crew access arm and lower it onto a flatbed truck at Precision Fabricating and Cleaning in Cocoa, Florida. The crew access arm will be transported to a storage location near NASA's Kennedy Space Center in Florida. Later this month, the arm will be transported to the mobile launcher (ML) tower at the center. The crew access arm will be located at about the 274-foot level on the tower. It will rotate from its retracted position and interface with the Orion crew hatch location to provide entry to the Orion crew module. The Ground Systems Development and Operations Program is overseeing installation of umbilicals and launch accessories on the ML tower.

  15. Accessing and operating agricultural machinery: Advancements in assistive technology for users with impaired mobility.

    PubMed

    Ehlers, Shawn G; Field, William E

    2018-02-14

    This research focused on the advancements made in enabling agricultural workers with impaired mobility to access and operate off-road agricultural machinery. Although not a new concept, technological advancements in remote-controlled lifts, electronic actuators, electric over hydraulic controllers, and various modes of hand controls have advanced significantly, allowing operators with limited mobility to resume a high level of productivity in agricultural-related enterprises. In the United States, approximately 1.7% of the population is living with some form of paralysis or significant mobility impairment. When paired with the 2012 USDA Agriculture Census of 3.2 million farmers, it can be extrapolated that these technologies could impact 54,000 agricultural workers who have encountered disabling injuries or disease, which inhibit their ability to access and operate tractors, combines, and other self-propelled agricultural machines. Advancements in agricultural-specific technologies can allow for many of these individuals to regain the ability to effectively operate machinery once more.

  16. An information theory criteria based blind method for enumerating active users in DS-CDMA system

    NASA Astrophysics Data System (ADS)

    Samsami Khodadad, Farid; Abed Hodtani, Ghosheh

    2014-11-01

    In this paper, a new and blind algorithm for active user enumeration in asynchronous direct sequence code division multiple access (DS-CDMA) in multipath channel scenario is proposed. The proposed method is based on information theory criteria. There are two main categories of information criteria which are widely used in active user enumeration, Akaike Information Criterion (AIC) and Minimum Description Length (MDL) information theory criteria. The main difference between these two criteria is their penalty functions. Due to this difference, MDL is a consistent enumerator which has better performance in higher signal-to-noise ratios (SNR) but AIC is preferred in lower SNRs. In sequel, we propose a SNR compliance method based on subspace and training genetic algorithm to have the performance of both of them. Moreover, our method uses only a single antenna, in difference to the previous methods which decrease hardware complexity. Simulation results show that the proposed method is capable of estimating the number of active users without any prior knowledge and the efficiency of the method.

  17. Nurses' use of mobile devices to access information in health care environments in australia: a survey of undergraduate students.

    PubMed

    Mather, Carey; Cummings, Elizabeth; Allen, Penny

    2014-12-10

    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. 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. A validated online survey was administered to students while on placement in a range of health care settings in two Australian states. 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. 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 their patients.

  18. The Potential Use of Mobile Technology: Enhancing Accessibility and Communication in a Blended Learning Course

    ERIC Educational Resources Information Center

    Mayisela, Tabisa

    2013-01-01

    Mobile technology is increasingly being used to support blended learning beyond computer centres. It has been considered as a potential solution to the problem of a shortage of computers for accessing online learning materials (courseware) in a blended learning course. The purpose of the study was to establish how the use of mobile technology…

  19. Using mobile technologies to give health students access to learning resources in the UK community setting.

    PubMed

    Walton, Graham; Childs, Susan; Blenkinsopp, Elizabeth

    2005-12-01

    This article describes a project which explored the potential for mobile technologies to give health students in the community access to learning resources. The purpose included the need to identify possible barriers students could face in using mobile technologies. Another focus was to assess the students perceptions of the importance of being able to access learning resources in the community. This 1-year project used two main approaches for data collection. A review of the literature on mobile technologies in the health context was conducted. This was used in a systematic way to identify key issues and trends. The literature review was used to inform the design and production of a questionnaire. This was distributed to and completed by a group of community health students at Northumbria University, UK. The questionnaire was piloted and there was a 100% completion rate with 49 returned forms. The literature review indicated that most mobile technology applications were occurring in the US. At the time of the review the most prevalent mobile technologies were PDAs, laptops, WAP phones and portable radios with use being concentrated around doctors in the acute sector. A range of advantages and disadvantages to the technology were discovered. Mobile technologies were mainly being used for clinical rather than learning applications. The students showed a low level of awareness of the technology but placed great importance to accessing learning resources from the community. Significant development and changes are taking place in mobile technologies. Since the data collection for this work was completed in 2004 podcasting and videocasting have become significant in mobile learning for health professionals. Librarians will need to address the relevance and implications of m-learning for their practice. Care and consideration needs to be given on the time and resources librarians allocate for the necessary development work around mobile technologies. Collaboration and

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

    PubMed

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

    2015-01-01

    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. RCSB PDB Mobile is freely available from the Apple App Store and Google Play (http://www.rcsb.org). © The Author 2014. Published by Oxford University Press.

  1. 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

  2. Forming a Cyber Coalition

    DTIC Science & Technology

    2012-04-06

    Estonia 6 :  98% of Estonian‟s territory was covered with Internet access: fixed line, broadband, WiMax, WiFi , and CDMA21 mobile wireless Internet...The hacked homepage displayed a prominent image of Bashar al-Assad, the President of Syria, with a text proclaiming “Syrian Electronic Army Were...update and harmonize their criminal laws against hacking , infringements on copyrights, computer facilitated fraud, child pornography, and other illicit

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

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

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

    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

  4. 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

  5. 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.

  6. 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

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

    PubMed

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

    2016-06-01

    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. The aim of this study is to determine user requirements, currently available resources, and perspectives for potential medical education technologies in Rwanda. 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? 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 locally adapted mobile education app

  8. Internet Use and Access Among Pregnant Women via Computer and Mobile Phone: Implications for Delivery of Perinatal Care

    PubMed Central

    Peragallo Urrutia, Rachel; Berger, Alexander A; Ivins, Amber A; Beckham, A Jenna; Thorp Jr, John M

    2015-01-01

    Background The use of Internet-based behavioral programs may be an efficient, flexible method to enhance prenatal care and improve pregnancy outcomes. There are few data about access to, and use of, the Internet via computers and mobile phones among pregnant women. Objective We describe pregnant women’s access to, and use of, computers, mobile phones, and computer technologies (eg, Internet, blogs, chat rooms) in a southern United States population. We describe the willingness of pregnant women to participate in Internet-supported weight-loss interventions delivered via computers or mobile phones. Methods We conducted a cross-sectional survey among 100 pregnant women at a tertiary referral center ultrasound clinic in the southeast United States. Data were analyzed using Stata version 10 (StataCorp) and R (R Core Team 2013). Means and frequency procedures were used to describe demographic characteristics, access to computers and mobile phones, and use of specific Internet modalities. Chi-square testing was used to determine whether there were differences in technology access and Internet modality use according to age, race/ethnicity, income, or children in the home. The Fisher’s exact test was used to describe preferences to participate in Internet-based postpartum weight-loss interventions via computer versus mobile phone. Logistic regression was used to determine demographic characteristics associated with these preferences. Results The study sample was 61.0% white, 26.0% black, 6.0% Hispanic, and 7.0% Asian with a mean age of 31.0 (SD 5.1). Most participants had access to a computer (89/100, 89.0%) or mobile phone (88/100, 88.0%) for at least 8 hours per week. Access remained high (>74%) across age groups, racial/ethnic groups, income levels, and number of children in the home. Internet/Web (94/100, 94.0%), email (90/100, 90.0%), and Facebook (50/100, 50.0%) were the most commonly used Internet technologies. Women aged less than 30 years were more likely to

  9. A novel PON based UMTS broadband wireless access network architecture with an algorithm to guarantee end to end QoS

    NASA Astrophysics Data System (ADS)

    Sana, Ajaz; Hussain, Shahab; Ali, Mohammed A.; Ahmed, Samir

    2007-09-01

    In this paper we proposes a novel Passive Optical Network (PON) based broadband wireless access network architecture to provide multimedia services (video telephony, video streaming, mobile TV, mobile emails etc) to mobile users. In the conventional wireless access networks, the base stations (Node B) and Radio Network Controllers (RNC) are connected by point to point T1/E1 lines (Iub interface). The T1/E1 lines are expensive and add up to operating costs. Also the resources (transceivers and T1/E1) are designed for peak hours traffic, so most of the time the dedicated resources are idle and wasted. Further more the T1/E1 lines are not capable of supporting bandwidth (BW) required by next generation wireless multimedia services proposed by High Speed Packet Access (HSPA, Rel.5) for Universal Mobile Telecommunications System (UMTS) and Evolution Data only (EV-DO) for Code Division Multiple Access 2000 (CDMA2000). The proposed PON based back haul can provide Giga bit data rates and Iub interface can be dynamically shared by Node Bs. The BW is dynamically allocated and the unused BW from lightly loaded Node Bs is assigned to heavily loaded Node Bs. We also propose a novel algorithm to provide end to end Quality of Service (QoS) (between RNC and user equipment).The algorithm provides QoS bounds in the wired domain as well as in wireless domain with compensation for wireless link errors. Because of the air interface there can be certain times when the user equipment (UE) is unable to communicate with Node B (usually referred to as link error). Since the link errors are bursty and location dependent. For a proposed approach, the scheduler at the Node B maps priorities and weights for QoS into wireless MAC. The compensations for errored links is provided by the swapping of services between the active users and the user data is divided into flows, with flows allowed to lag or lead. The algorithm guarantees (1)delay and throughput for error-free flows,(2)short term fairness

  10. Mobile Launcher Crew Access Arm Transport from Cocoa FL to KSC

    NASA Image and Video Library

    2017-10-17

    The Orion crew access arm is secured on a flatbed truck at Precision Fabricating and Cleaning in Cocoa, Florida and ready to be transported to a storage location at NASA's Kennedy Space Center in Florida. Later this month, the arm will be transported to the mobile launcher (ML) tower at the center. The crew access arm will be located at about the 274-foot level on the tower. It will rotate from its retracted position and interface with the Orion crew hatch location to provide entry to the Orion crew module. The Ground Systems Development and Operations Program is overseeing installation of umbilicals and launch accessories on the ML tower.

  11. 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.

  12. Effects of mobile phone use on specific intensive care unit devices.

    PubMed

    Hans, Nidhi; Kapadia, Farhad N

    2008-10-01

    To observe the effects of mobile phone use in the vicinity of medical devices used in a critical care setting. Electromagnetic interference (EMI) was tested by using two types of mobile phones - GSM and CDMA. Mobile phones were placed at a distance of one foot from three medical devices - syringe pump, mechanical ventilator, and the bedside monitor - in switch off, standby, and talking modes of the phone. Medical devices were observed for any interference caused by the electromagnetic radiations (EMR) from the mobile phones. Out of the three medical devices that were tested, EMI occurred while using the mobile phone in the vicinity of the syringe pump, in the 'talk mode.' The mean variation observed in the calculated and delivered volume of the syringe pump was 2.66 ml. Mechanical ventilator did not show any specific adverse effects with mobile phone use in the one-foot vicinity. No other adverse effects or unexplained malfunctions or shutdown of the syringe pump, mechanical ventilator, or the bedside monitor was noted during the study period of 36 hours. EMI from mobile phones have an adverse effect on the medical devices used in critical care setup. They should be used at least one foot away from the diameter of the syringe pump.

  13. 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. Copyright © 2011 Wiley Periodicals, Inc.

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

    PubMed

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

    2016-01-01

    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. To assess the feasibility of a fully mobile randomised controlled trial using assessments and treatments delivered entirely through mobile devices to depressed individuals. 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. A cognitive training application, an application based on problem-solving therapy, and a mobile-sensing application promoting daily activities. 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. 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. NCT00540865.

  15. A Novel Design of Reconfigurable Wavelength-Time Optical Codes to Enhance Security in Optical CDMA Networks

    NASA Astrophysics Data System (ADS)

    Nasaruddin; Tsujioka, Tetsuo

    An optical CDMA (OCDMA) system is a flexible technology for future broadband multiple access networks. A secure OCDMA network in broadband optical access technologies is also becoming an issue of great importance. In this paper, we propose novel reconfigurable wavelength-time (W-T) optical codes that lead to secure transmission in OCDMA networks. The proposed W-T optical codes are constructed by using quasigroups (QGs) for wavelength hopping and one-dimensional optical orthogonal codes (OOCs) for time spreading; we call them QGs/OOCs. Both QGs and OOCs are randomly generated by a computer search to ensure that an eavesdropper could not improve its interception performance by making use of the coding structure. Then, the proposed reconfigurable QGs/OOCs can provide more codewords, and many different code set patterns, which differ in both wavelength and time positions for given code parameters. Moreover, the bit error probability of the proposed codes is analyzed numerically. To realize the proposed codes, a secure system is proposed by employing reconfigurable encoders/decoders based on array waveguide gratings (AWGs), which allow the users to change their codeword patterns to protect against eavesdropping. Finally, the probability of breaking a certain codeword in the proposed system is evaluated analytically. The results show that the proposed codes and system can provide a large codeword pattern, and decrease the probability of breaking a certain codeword, to enhance OCDMA network security.

  16. Characteristics of clients who access mobile compared to clinic HIV counselling and testing services: a matched study from Cape Town, South Africa.

    PubMed

    Meehan, Sue-Ann; Naidoo, Pren; Claassens, Mareli M; Lombard, Carl; Beyers, Nulda

    2014-12-20

    Studies within sub-Saharan African countries have shown that mobile services increase uptake of HIV counselling and testing (HCT) services when compared to clinics and are able to access different populations, but these have included provider-initiated HCT in clinics. This study aimed to compare the characteristics of clients who self-initiated HCT at either a mobile or a clinic service in terms of demographic and socio-economic variables, also comparing reasons for accessing a particular health service provider. This study took place in eight areas around Cape Town. A matched design was used with one mobile HCT service matched with one or more clinics (offering routine HCT services) within each of the eight areas. Adult clients who self-referred for an HIV test within a specified time period at either a mobile or clinic service were invited to participate in the study. Data were collected between February and April 2011 using a questionnaire. Summary statistics were calculated for each service type within a matched pair and differences of outcomes from pairs were used to calculate effect sizes and 95% confidence intervals. 1063 participants enrolled in the study with 511 from mobile and 552 from clinic HCT services. The proportion of males accessing mobile HCT significantly exceeded that of clinic HCT (p < 0.001). The mean age of participants attending mobile HCT was higher than clinic participants (p = 0.023). No significant difference was found for socio-economic variables between participants, with the exception of access to own piped water (p = 0.029). Participants who accessed mobile HCT were significantly more likely to report that they were just passing, deemed an "opportunistic" visit (p = 0.014). Participants who accessed clinics were significantly more likely to report the service being close to home or work (p = 0.035). An HCT strategy incorporating a mobile HCT service, has a definite role to play in reaching those population groups who do

  17. Access, Outcomes, and Social Mobility in a Stratified System of Postsecondary Education

    ERIC Educational Resources Information Center

    Thompson, Jason

    2017-01-01

    Educational attainment sits at the core of research on social stratification in the United States. An extensive literature details the inequalities in access to levels of education, the socioeconomic rewards conferred upon those reaching higher levels of schooling, and the prospects for social mobility among those able to attain a college degree.…

  18. Relationships between Access to Mobile Devices, Student Self-Directed Learning, and Achievement

    ERIC Educational Resources Information Center

    Bartholomew, Scott R.; Reeve, Ed; Veon, Raymond; Goodridge, Wade; Lee, Victor; Nadelson, Louis

    2017-01-01

    Today's students are growing up in a world of constant connectivity, instant information, and ever-changing technological advancements. The increasingly ubiquitous nature of mobile devices among K-12 students has led many to argue for and against the inclusion of these devices in K-12 classrooms. Arguments in favor cite instant access to…

  19. 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

  20. Performance Analysis of a De-correlated Modified Code Tracking Loop for Synchronous DS-CDMA System under Multiuser Environment

    NASA Astrophysics Data System (ADS)

    Wu, Ya-Ting; Wong, Wai-Ki; Leung, Shu-Hung; Zhu, Yue-Sheng

    This paper presents the performance analysis of a De-correlated Modified Code Tracking Loop (D-MCTL) for synchronous direct-sequence code-division multiple-access (DS-CDMA) systems under multiuser environment. Previous studies have shown that the imbalance of multiple access interference (MAI) in the time lead and time lag portions of the signal causes tracking bias or instability problem in the traditional correlating tracking loop like delay lock loop (DLL) or modified code tracking loop (MCTL). In this paper, we exploit the de-correlating technique to combat the MAI at the on-time code position of the MCTL. Unlike applying the same technique to DLL which requires an extensive search algorithm to compensate the noise imbalance which may introduce small tracking bias under low signal-to-noise ratio (SNR), the proposed D-MCTL has much lower computational complexity and exhibits zero tracking bias for the whole range of SNR, regardless of the number of interfering users. Furthermore, performance analysis and simulations based on Gold codes show that the proposed scheme has better mean square tracking error, mean-time-to-lose-lock and near-far resistance than the other tracking schemes, including traditional DLL (T-DLL), traditional MCTL (T-MCTL) and modified de-correlated DLL (MD-DLL).

  1. A Joint Optimization Criterion for Blind DS-CDMA Detection

    NASA Astrophysics Data System (ADS)

    Durán-Díaz, Iván; Cruces-Alvarez, Sergio A.

    2006-12-01

    This paper addresses the problem of the blind detection of a desired user in an asynchronous DS-CDMA communications system with multipath propagation channels. Starting from the inverse filter criterion introduced by Tugnait and Li in 2001, we propose to tackle the problem in the context of the blind signal extraction methods for ICA. In order to improve the performance of the detector, we present a criterion based on the joint optimization of several higher-order statistics of the outputs. An algorithm that optimizes the proposed criterion is described, and its improved performance and robustness with respect to the near-far problem are corroborated through simulations. Additionally, a simulation using measurements on a real software-radio platform at 5 GHz has also been performed.

  2. Access point selection game with mobile users using correlated equilibrium.

    PubMed

    Sohn, Insoo

    2015-01-01

    One of the most important issues in wireless local area network (WLAN) systems with multiple access points (APs) is the AP selection problem. Game theory is a mathematical tool used to analyze the interactions in multiplayer systems and has been applied to various problems in wireless networks. Correlated equilibrium (CE) is one of the powerful game theory solution concepts, which is more general than the Nash equilibrium for analyzing the interactions in multiplayer mixed strategy games. A game-theoretic formulation of the AP selection problem with mobile users is presented using a novel scheme based on a regret-based learning procedure. Through convergence analysis, we show that the joint actions based on the proposed algorithm achieve CE. Simulation results illustrate that the proposed algorithm is effective in a realistic WLAN environment with user mobility and achieves maximum system throughput based on the game-theoretic formulation.

  3. Access Point Selection Game with Mobile Users Using Correlated Equilibrium

    PubMed Central

    Sohn, Insoo

    2015-01-01

    One of the most important issues in wireless local area network (WLAN) systems with multiple access points (APs) is the AP selection problem. Game theory is a mathematical tool used to analyze the interactions in multiplayer systems and has been applied to various problems in wireless networks. Correlated equilibrium (CE) is one of the powerful game theory solution concepts, which is more general than the Nash equilibrium for analyzing the interactions in multiplayer mixed strategy games. A game-theoretic formulation of the AP selection problem with mobile users is presented using a novel scheme based on a regret-based learning procedure. Through convergence analysis, we show that the joint actions based on the proposed algorithm achieve CE. Simulation results illustrate that the proposed algorithm is effective in a realistic WLAN environment with user mobility and achieves maximum system throughput based on the game-theoretic formulation. PMID:25785726

  4. 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.

  5. 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

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

    PubMed

    Iezzoni, Lisa I; Wint, Amy J; Smeltzer, Suzanne C; Ecker, Jeffrey L

    2015-12-01

    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. 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. 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. 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.

  7. Cloud-assisted mobile-access of health data with privacy and auditability.

    PubMed

    Tong, Yue; Sun, Jinyuan; Chow, Sherman S M; Li, Pan

    2014-03-01

    Motivated by the privacy issues, curbing the adoption of electronic healthcare systems and the wild success of cloud service models, we propose to build privacy into mobile healthcare systems with the help of the private cloud. Our system offers salient features including efficient key management, privacy-preserving data storage, and retrieval, especially for retrieval at emergencies, and auditability for misusing health data. Specifically, we propose to integrate key management from pseudorandom number generator for unlinkability, a secure indexing method for privacy-preserving keyword search which hides both search and access patterns based on redundancy, and integrate the concept of attribute-based encryption with threshold signing for providing role-based access control with auditability to prevent potential misbehavior, in both normal and emergency cases.

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

    NASA Astrophysics Data System (ADS)

    Kaur, Navpreet; Goyal, Rakesh; Rani, Monika

    2017-06-01

    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.

  9. 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. Copyright © 2013 Wiley Periodicals, Inc.

  10. 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

  11. 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. © 2014 Wiley Periodicals, Inc.

  12. 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.

  13. Access and Mobilization: How Social Capital Relates to Low-Income Youth's Postsecondary Educational (PSE) Attainment

    ERIC Educational Resources Information Center

    Ashtiani, Mariam; Feliciano, Cynthia

    2018-01-01

    Youth from advantaged backgrounds have more social relationships that provide access to resources facilitating their educational success than those from low-income families. Does access to and mobilization of social capital also relate to success among the few low-income youth who "overcome the odds" and persist in higher education?…

  14. 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

    ... FEDERAL COMMUNICATIONS COMMISSION [CG Docket No. 10-145; DA 10-1324] Accessible Mobile Phone Options for People Who Are Blind, Deaf- Blind, or Have Low Vision AGENCY: Federal Communications... wireless communication access by these populations; the cost and feasibility of technical solutions to...

  15. Optimizing physician access to surgical intensive care unit laboratory information through mobile computing.

    PubMed

    Strain, J J; Felciano, R M; Seiver, A; Acuff, R; Fagan, L

    1996-01-01

    Approximately 30 minutes of computer access time are required by surgical residents at Stanford University Medical Center (SUMC) to examine the lab values of all patients on a surgical intensive care unit (ICU) service, a task that must be performed several times a day. To reduce the time accessing this information and simultaneously increase the readability and currency of the data, we have created a mobile, pen-based user interface and software system that delivers lab results to surgeons in the ICU. The ScroungeMaster system, loaded on a portable tablet computer, retrieves lab results for a subset of patients from the central laboratory computer and stores them in a local database cache. The cache can be updated on command; this update takes approximately 2.7 minutes for all ICU patients being followed by the surgeon, and can be performed as a background task while the user continues to access selected lab results. The user interface presents lab results according to physiologic system. Which labs are displayed first is governed by a layout selection algorithm based on previous accesses to the patient's lab information, physician preferences, and the nature of the patient's medical condition. Initial evaluation of the system has shown that physicians prefer the ScroungeMaster interface to that of existing systems at SUMC and are satisfied with the system's performance. We discuss the evolution of ScroungeMaster and make observations on changes to physician work flow with the presence of mobile, pen-based computing in the ICU.

  16. 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.

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

    NASA Astrophysics Data System (ADS)

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

    1984-11-01

    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.

  18. Demographics and Trends in Wheeled Mobility Equipment Use and Accessibility in the Community

    ERIC Educational Resources Information Center

    LaPlante, Mitchell P.; Kaye, H. Stephen

    2010-01-01

    This article presents a profile of household-resident U.S. adults using wheeled mobility equipment (WME) in 2005, trends in WME use from 1990 to 2005, and data on accessibility features and problems from 1994-97. Data were obtained from the Survey of Income and Program Participation (SIPP) and the National Health Interview Survey on Disability…

  19. 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.

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

    PubMed

    Chien, Tsair-Wei; Lin, Weir-Sen

    2016-03-02

    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. 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. 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. 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. 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.

  1. Exploring accessibility issues of a public building for the mobility impaired. Case study: interstate bus terminal (ISBT), Vijayawada, India.

    PubMed

    Alagappan, Valliappan; Hefferan, Albert; Parivallal, Aarthi

    2018-04-01

    Right to access in the built environment creates equal and nondiscriminatory opportunities to a person with disabilities in order to move freely around and interact positively without hindrance and barriers. The objective of the study is to understand the existing accessibility related issues and implementation of guidelines and standards for public buildings. The technical verification using onsite and offsite access audit format for current provision of facilities in the internal and external environment has been carried out with the format prepared in reference to Central Public Works Department (CPWD) accessibility guidelines for mobility impaired and elderly and American Disability Act (ADA) guidelines. The access audit format included parameters like accessibility, safety, security, comfort and convenience and it addresses the barriers faced by wheel chair users, people with crutches, prosthetics and with non-assistive devices. The study addressed accessibility compliance in three zones of the building with initiation from parking area zone, inside the building, and area outside the building premises. The findings highlight the environmental barriers encountered by mobility impaired people and represented graphically in the layout plan and physical effort required to overcome the challenges in the built environment. The overall accessibility compliance is 42% in the interstate bus terminal. Implications for rehabilitation The study identifies the environmental limitations, human and technologically facilitators with the help of Central Public Works Department (CPWD) and American Disability Act (ADA) guidelines (1990). It highlights barriers for mobility-impaired users, by demonstrating in a spatial layout and the means to facilitate easy access with minimal frustration, stress and with less physical effort. It demonstrates the need for preparation of separate guidelines for making the existing types of buildings to be access and disabled-friendly. New

  2. Utilizing Spectrum Efficiently (USE)

    DTIC Science & Technology

    2011-02-28

    18 4.8 Space-Time Coded Asynchronous DS - CDMA with Decentralized MAI Suppression: Performance and...numerical results. 4.8 Space-Time Coded Asynchronous DS - CDMA with Decentralized MAI Suppression: Performance and Spectral Efficiency In [60] multiple...supported at a given signal-to-interference ratio in asynchronous direct-sequence code-division multiple-access ( DS - CDMA ) sys- tems was examined. It was

  3. The use of mobile devices as assistive technology in resource-limited environments: access for learners with visual impairments in Kenya.

    PubMed

    Foley, Alan R; Masingila, Joanna O

    2015-07-01

    In this paper, the authors explore the use of mobile devices as assistive technology for students with visual impairments in resource-limited environments. This paper provides initial data and analysis from an ongoing project in Kenya using tablet devices to provide access to education and independence for university students with visual impairments in Kenya. The project is a design-based research project in which we have developed and are refining a theoretically grounded intervention--a model for developing communities of practice to support the use of mobile technology as an assistive technology. We are collecting data to assess the efficacy and improve the model as well as inform the literature that has guided the design of the intervention. In examining the impact of the use of mobile devices for the students with visual impairments, we found that the devices provide the students with (a) access to education, (b) the means to participate in everyday life and (c) the opportunity to create a community of practice. Findings from this project suggest that communities of practice are both a viable and a valuable approach for facilitating the diffusion and support of mobile devices as assistive technology for students with visual impairments in resource-limited environments. Implications for Rehabilitation The use of mobile devices as assistive technology in resource-limited environments provides students with visual impairments access to education and enhanced means to participate in everyday life. Communities of practice are both a viable and a valuable approach for facilitating the diffusion and support of mobile devices as assistive technology for students with visual impairments in resource-limited environments. Providing access to assistive technology early and consistently throughout students' schooling builds both their skill and confidence and also demonstrates the capabilities of people with visual impairments to the larger society.

  4. 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

  5. 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

  6. Evaluation of generic medical information accessed via mobile phones at the point of care in resource-limited settings

    PubMed Central

    Goldbach, Hayley; Chang, Aileen Y; Kyer, Andrea; Ketshogileng, Dineo; Taylor, Lynne; Chandra, Amit; Dacso, Matthew; Kung, Shiang-Ju; Rijken, Taatske; Fontelo, Paul; Littman-Quinn, Ryan; Seymour, Anne K; Kovarik, Carrie L

    2014-01-01

    Objective Many mobile phone resources have been developed to increase access to health education in the developing world, yet few studies have compared these resources or quantified their performance in a resource-limited setting. This study aims to compare the performance of resident physicians in answering clinical scenarios using PubMed abstracts accessed via the PubMed for Handhelds (PubMed4Hh) website versus medical/drug reference applications (Medical Apps) accessed via software on the mobile phone. Methods A two-arm comparative study with crossover design was conducted. Subjects, who were resident physicians at the University of Botswana, completed eight scenarios, each with multi-part questions. The primary outcome was a grade for each question. The primary independent variable was the intervention arm and other independent variables included residency and question. Results Within each question type there were significant differences in ‘percentage correct’ between Medical Apps and PubMed4Hh for three of the six types of questions: drug-related, diagnosis/definitions, and treatment/management. Within each of these question types, Medical Apps had a higher percentage of fully correct responses than PubMed4Hh (63% vs 13%, 33% vs 12%, and 41% vs 13%, respectively). PubMed4Hh performed better for epidemiologic questions. Conclusions While mobile access to primary literature remains important and serves an information niche, mobile applications with condensed content may be more appropriate for point-of-care information needs. Further research is required to examine the specific information needs of clinicians in resource-limited settings and to evaluate the appropriateness of current resources in bridging location- and context-specific information gaps. PMID:23535665

  7. Performance Analysis of Iterative Channel Estimation and Multiuser Detection in Multipath DS-CDMA Channels

    NASA Astrophysics Data System (ADS)

    Li, Husheng; Betz, Sharon M.; Poor, H. Vincent

    2007-05-01

    This paper examines the performance of decision feedback based iterative channel estimation and multiuser detection in channel coded aperiodic DS-CDMA systems operating over multipath fading channels. First, explicit expressions describing the performance of channel estimation and parallel interference cancellation based multiuser detection are developed. These results are then combined to characterize the evolution of the performance of a system that iterates among channel estimation, multiuser detection and channel decoding. Sufficient conditions for convergence of this system to a unique fixed point are developed.

  8. 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.

  9. Experiences of registered nurses with regard to accessing health information at the point-of-care via mobile computing devices.

    PubMed

    Ricks, Esmeralda; Benjamin, Valencia; Williams, Margaret

    2015-11-19

    The volume of health information necessary to provide competent health care today has become overwhelming. Mobile computing devices are fast becoming an essential clinical tool for accessing health information at the point-of-care of patients. This study explored and described how registered nurses experienced accessing information at the point-of-care via mobile computing devices (MCDs). A qualitative, exploratory, descriptive and contextual design was used. Ten in-depth interviews were conducted with purposively sampled registered nurses employed by a state hospital in the Nelson Mandela Bay Municipality (NMBM). Interviews were recorded, transcribed verbatim and analysed using Tesch's data analysis technique. Ethical principles were adhered to throughout the study. Guba's model of trustworthiness was used to confirm integrity of the study. Four themes emerged which revealed that the registered nurses benefited from the training they received by enabling them to develop, and improve, their computer literacy levels. Emphasis was placed on the benefits that the accessed information had for educational purposes for patients and the public, for colleagues and students. Furthermore the ability to access information at the point-of-care was considered by registered nurses as valuable to improve patient care because of the wide range of accurate and readily accessible information available via the mobile computing device. The registered nurses in this study felt that being able to access information at the point-of-care increased their confidence and facilitated the provision of quality care because it assisted them in being accurate and sure of what they were doing.

  10. 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.

  11. 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.

  12. 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

  13. ROSA: Distributed Joint Routing and Dynamic Spectrum Allocation in Cognitive Radio Ad Hoc Networks

    DTIC Science & Technology

    2010-03-01

    Aug. 1999. [20] I. N. Psaromiligkos and S. N. Batalama. Rapid Combined Synchronization/Demodulation Structures for DS - CDMA Systems - Part II: Finite...Medley. Rapid Combined Synchronization/Demodulation Structures for DS - CDMA Systems - Part I: Algorithmic developments. IEEE Transactions on...multiple access ( CDMA ) [21][20] al- low concurrent co-located communications so that a message from node i to node j can be correctly received even if

  14. Hybrid evolutionary computing model for mobile agents of wireless Internet multimedia

    NASA Astrophysics Data System (ADS)

    Hortos, William S.

    2001-03-01

    agents on a host station sharing a common goal can be merged or married to compose a new agent. Application of the two-layer set of algorithms for mobile agent evolution, performed in a distributed processing environment, is made to the QoS management functions of the IP multimedia IM sub-network of the third generation 3G Wideband Code-division Multiple Access W-CDMA wireless network.

  15. 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.

  16. Do vehicle grants and vehicle adaptations grants promote transport mobility and community access for children with disabilities in Sweden?

    PubMed

    Sjödin, Linda; Buchanan, Angus; Mundt, Beate; Karlsson, Emelie; Falkmer, Torbjörn

    2012-02-01

    A vast majority of the journeys made by children with disabilities in Sweden are in the family car, which usually is bought and adapted for the child with governmental subsidies. Despite the important philosophical views about accessible vehicles, little is known about the impact of vehicle adaptations on families' lives. The aim of the study was to investigate parent views about the impact of vehicle grants and vehicle adaptation grants on their children's transport mobility and community access. In total, 434 parents of children with disabilities in Sweden who had received vehicle grants and/or vehicle adaptation grants between 1998-2007 responded to a questionnaire comprising questions with both pre-selected and open-ended answers. A non-responder analysis was performed. Children with disabilities were found to increase their transport mobility and community access in society as vehicle grants and/or vehicle adaptation grants were given to their parents. Their travel patterns and their travel priorities with their family car indicated that family friends and relatives and leisure activities were frequently visited and prioritised destinations. The grants were linked to access to social and family activities, provided environmental gains and led to increased experienced security. The results also showed that the potential to make spontaneous trips had increased substantially and that families experienced feelings of freedom and enhanced community access. The non-responder analysis confirmed these results. According to parents, vehicle grants and vehicle adaptation grants for children with disabilities have a positive impact on the children's transport mobility and community access. © 2011 The Authors. Australian Occupational Therapy Journal © 2011 Occupational Therapy Australia.

  17. Rethinking mobile delivery: using Quick Response codes to access information at the point of need.

    PubMed

    Lombardo, Nancy T; Morrow, Anne; Le Ber, Jeanne

    2012-01-01

    This article covers the use of Quick Response (QR) codes to provide instant mobile access to information, digital collections, educational offerings, library website, subject guides, text messages, videos, and library personnel. The array of uses and the value of using QR codes to push customized information to patrons are explained. A case is developed for using QR codes for mobile delivery of customized information to patrons. Applications in use at the Libraries of the University of Utah will be reviewed to provide readers with ideas for use in their library. Copyright © Taylor & Francis Group, LLC

  18. Adaptive Digital Signature Design and Short-Data-Record Adaptive Filtering

    DTIC Science & Technology

    2008-04-01

    rate BPSK binary phase shift keying CA − CFAR cell averaging− constant false alarm rate CDMA code − division multiple − access CFAR constant false...Cotae, “Spreading sequence design for multiple cell synchronous DS-CDMA systems under total weighted squared correlation criterion,” EURASIP Journal...415-428, Mar. 2002. [6] P. Cotae, “Spreading sequence design for multiple cell synchronous DS-CDMA systems under total weighted squared correlation

  19. 75 FR 35989 - Facilitating the Provision of Fixed and Mobile Broadband Access, Educational and Other Advanced...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-06-24

    ...] Facilitating the Provision of Fixed and Mobile Broadband Access, Educational and Other Advanced Services in the...), clarifying the requirements necessary for Broadband Radio Service (BRS) and Educational Broadband Service (EBS) licensees to demonstrate substantial service and ensure that BRS licensees of new initial...

  20. mobile Digital Access to a Web-enhanced Network (mDAWN): Assessing the Feasibility of Mobile Health Tools for Self-Management of Type-2 Diabetes.

    PubMed

    Ho, Kendall; Newton, Lana; Boothe, Allison; Novak-Lauscher, Helen

    2015-01-01

    The mobile Digital Access to a Web-enhanced Network (mDAWN) program was implemented as an online, mobile self-management system to support patients with type-2 diabetes and their informal caregivers. Patients used wireless physiological sensors, received text messages, and had access to a secure web platform with health resources and semi-facilitated discussion forum. Outcomes were evaluated using (1) pre and post self-reported health behavior measures, (2) physiological outcomes, (3) program cost, and (4) in-depth participant interviews. The group had significantly decreased health distress, HbA1c levels, and systolic blood pressure. Participants largely saw the mDAWN as providing good value for the costs involved and found the program to be empowering in gaining control over their diabetes. mHealth programs have the potential to improve clinical outcomes through cost effective patient-led care for chronic illness. Further evaluation needs to examine integration of similar mHealth programs into the patient-physician relationship.

  1. Mobile access to virtual randomization for investigator-initiated trials.

    PubMed

    Deserno, Thomas M; Keszei, András P

    2017-08-01

    Background/aims Randomization is indispensable in clinical trials in order to provide unbiased treatment allocation and a valid statistical inference. Improper handling of allocation lists can be avoided using central systems, for example, human-based services. However, central systems are unaffordable for investigator-initiated trials and might be inaccessible from some places, where study subjects need allocations. We propose mobile access to virtual randomization, where the randomization lists are non-existent and the appropriate allocation is computed on demand. Methods The core of the system architecture is an electronic data capture system or a clinical trial management system, which is extended by an R interface connecting the R server using the Java R Interface. Mobile devices communicate via the representational state transfer web services. Furthermore, a simple web-based setup allows configuring the appropriate statistics by non-statisticians. Our comprehensive R script supports simple randomization, restricted randomization using a random allocation rule, block randomization, and stratified randomization for un-blinded, single-blinded, and double-blinded trials. For each trial, the electronic data capture system or the clinical trial management system stores the randomization parameters and the subject assignments. Results Apps are provided for iOS and Android and subjects are randomized using smartphones. After logging onto the system, the user selects the trial and the subject, and the allocation number and treatment arm are displayed instantaneously and stored in the core system. So far, 156 subjects have been allocated from mobile devices serving five investigator-initiated trials. Conclusion Transforming pre-printed allocation lists into virtual ones ensures the correct conduct of trials and guarantees a strictly sequential processing in all trial sites. Covering 88% of all randomization models that are used in recent trials, virtual randomization

  2. User needs for propagation data

    NASA Technical Reports Server (NTRS)

    Sullivan, Thomas M.

    1993-01-01

    New and refined models of radio signal propagation phenomena are needed to support studies of evolving satellite services and systems. Taking an engineering perspective, applications for propagation measurements and models in the context of various types of analyses that are of ongoing interest are reviewed. Problems that were encountered in the signal propagation aspects of these analyses are reviewed, and potential solutions to these problems are discussed. The focus is on propagation measurements and models needed to support design and performance analyses of systems in the Mobile-Satellite Service (MSS) operating in the 1-3 GHz range. These systems may use geostationary or non-geostationary satellites and Frequency Division Multiple Access (FDMA), Time Division Multiple Access Digital (TDMA), or Code Division Multiple Access (CDMA) techniques. Many of the propagation issues raised in relation to MSS are also pertinent to other services such as broadcasting-satellite (sound) at 2310-2360 MHz. In particular, services involving mobile terminals or terminals with low gain antennas are of concern.

  3. Enabling technologies for millimeter-wave radio-over-fiber systems in next generation heterogeneous mobile access networks

    NASA Astrophysics Data System (ADS)

    Zhang, Junwen; Yu, Jianjun; Wang, Jing; Xu, Mu; Cheng, Lin; Lu, Feng; Shen, Shuyi; Yan, Yan; Cho, Hyunwoo; Guidotti, Daniel; Chang, Gee-kung

    2017-01-01

    Fifth-generation (5G) wireless access network promises to support higher access data rate with more than 1,000 times capacity with respect to current long-term evolution (LTE) systems. New radio-access-technologies (RATs) based on higher carrier frequencies to millimeter-wave (MMW) radio-over-fiber, and carrier-aggregation (CA) using multi-band resources are intensively studied to support the high data rate access and effectively use of frequency resources in heterogeneous mobile network (Het-Net). In this paper, we investigate several enabling technologies for MMW RoF systems in 5G Het-Net. Efficient mobile fronthaul (MFH) solutions for 5G centralized radio access network (C-RAN) and beyond are proposed, analyzed and experimentally demonstrated based on the analog scheme. Digital predistortion based on memory polynomial for analog MFH linearization are presented with improved EVM performances and receiver sensitivity. We also propose and experimentally demonstrate a novel inter-/intra- RAT CA scheme for 5G Het- Net. The real-time standard 4G-LTE signal is carrier-aggregated with three broadband 60GHz MMW signals based on proposed optical-domain band-mapping method. RATs based on new waveforms have also been studied here to achieve higher spectral-efficiency (SE) in asynchronous environments. Full-duplex asynchronous quasi-gapless carrier aggregation scheme for MMW ROF inter-/intra-RAT based on the FBMC is also presented with 4G-LTE signals. Compared with OFDM-based signals with large guard-bands, FBMC achieves higher spectral-efficiency with better EVM performance at less received power and smaller guard-bands.

  4. A Code Division Multiple Access Communication System for the Low Frequency Band.

    DTIC Science & Technology

    1983-04-01

    frequency channels spread-spectrum communication / complex sequences, orthogonal codes impulsive noise 20. ABSTRACT (Continue an reverse side It...their transmissions with signature sequences. Our LF/CDMA scheme is different in that each user’s signature sequence set consists of M orthogonal ...signature sequences. Our LF/CDMA scheme is different in that each user’s signature sequence set consists of M orthogonal sequences and thus log 2 M

  5. Wireless Technology

    DTIC Science & Technology

    2009-03-01

    section, we use as an illustration vehicle for the proposed GLRT schemes a packet-data DS - CDMA communication system2. At all times, the GLRT detectors...are imple- 2The combined effect of DS - CDMA multiple access interference (MAI) and AWGN is Gaussian-mixture distributed and not plain Gaussian. It is...closely to the SMI detector in (9) and outperforms all other detectors. DS - CDMA Case-study #2 Asynchronous multipath fading channel: Pilot-assisted

  6. Bi-orthogonal Symbol Mapping and Detection in Optical CDMA Communication System

    NASA Astrophysics Data System (ADS)

    Liu, Maw-Yang

    2017-12-01

    In this paper, the bi-orthogonal symbol mapping and detection scheme is investigated in time-spreading wavelength-hopping optical CDMA communication system. The carrier-hopping prime code is exploited as signature sequence, whose put-of-phase autocorrelation is zero. Based on the orthogonality of carrier-hopping prime code, the equal weight orthogonal signaling scheme can be constructed, and the proposed scheme using bi-orthogonal symbol mapping and detection can be developed. The transmitted binary data bits are mapped into corresponding bi-orthogonal symbols, where the orthogonal matrix code and its complement are utilized. In the receiver, the received bi-orthogonal data symbol is fed into the maximum likelihood decoder for detection. Under such symbol mapping and detection, the proposed scheme can greatly enlarge the Euclidean distance; hence, the system performance can be drastically improved.

  7. "Socioeconomic inequalities in children's accessibility to food retailing: Examining the roles of mobility and time".

    PubMed

    Ravensbergen, Léa; Buliung, Ron; Wilson, Kathi; Faulkner, Guy

    2016-03-01

    Childhood overweight and obesity rates in Canada are at concerning levels, more apparently so for individuals of lower socioeconomic status (SES). Accessibility to food establishments likely influences patterns of food consumption, a contributor to body weight. Previous work has found that households living in lower income neighbourhoods tend to have greater geographical accessibility to unhealthy food establishments and lower accessibility to healthy food stores. This study contributes to the literature on neighbourhood inequalities in accessibility to healthy foods by explicitly focusing on children, an understudied population, and by incorporating mobility and time into metrics of accessibility. Accessibility to both healthy and unhealthy food retailing is measured within children's activity spaces using Road Network and Activity Location Buffering methods. Weekday vs. weekend accessibility to food establishments is then compared. The results suggest that children attending lower SES schools had almost two times the density of fast food establishments and marginally higher supermarket densities in their activity spaces. Children attending higher SES schools also had much larger activity spaces. All children had higher supermarket densities during weekdays than on weekend days. Copyright © 2016 Elsevier Ltd. All rights reserved.

  8. 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. © The Author(s) 2014 Reprints and permissions: sagepub.co.uk/journalsPermissions.nav.

  9. Wideband Channel Modeling in Real Atmospheric Environments with Experimental Evaluation

    DTIC Science & Technology

    2013-04-01

    5] D. F. Gingras and P. Gerstoft. 1997. “The Effect of Propagation on Wideband DS - CDMA Systems in the Suburban Environment,” The First IEEE...are commonly used in spread spectrum communication systems such as Code Division Multiple Access ( CDMA ) systems. Narrowband interference mitigation

  10. Cognitive Code-Division Channelization

    DTIC Science & Technology

    2011-04-01

    22] G. N. Karystinos and D. A. Pados, “New bounds on the total squared correlation and optimum design of DS - CDMA binary signature sets,” IEEE Trans...Commun., vol. 51, pp. 48-51, Jan. 2003. [23] C. Ding, M. Golin, and T. Klve, “Meeting the Welch and Karystinos- Pados bounds on DS - CDMA binary...receiver pair coexisting with a primary code-division multiple-access ( CDMA ) system. Our objective is to find the optimum transmitting power and code

  11. Interference Analysis for Highly Directional 60 GHz Mesh Networks: The Case for Rethinking Medium Access Control

    DTIC Science & Technology

    2010-11-24

    Helmken, “Performance analysis of coherent DS - CDMA systems in a Nakagami fading channel with arbitrary parameters,” Vehicular Technology, IEEE...Transactions on, vol. 46, no. 2, pp. 289–297, may 1997. [26] M. Sunay and P. McLane, “Calculating error probabilities for DS - CDMA systems: when not to use

  12. 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.

  13. 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

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

    PubMed

    Brusk, John J; Bensley, Robert J

    2016-11-15

    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. 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). 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. Analysis of 8 user characteristics (lessons completed, race, ethnicity, language, state of residence, pregnancy status, beginning stage of change, and preferred nutrition education method) were

  15. 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.

  16. 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…

  17. A Portable Farmland Information Collection System with Multiple Sensors.

    PubMed

    Zhang, Jianfeng; Hu, Jinyang; Huang, Lvwen; Zhang, Zhiyong; Ma, Yimian

    2016-10-22

    Precision agriculture is the trend of modern agriculture, and it is also one of the important ways to realize the sustainable development of agriculture. In order to meet the production requirements of precision agriculture-efficient use of agricultural resources, and improving the crop yields and quality-some necessary field information in crop growth environment needs to be collected and monitored. In this paper, a farmland information collection system is developed, which includes a portable farmland information collection device based on STM32 (a 32-bit comprehensive range of microcontrollers based on ARM Crotex-M3), a remote server and a mobile phone APP. The device realizes the function of portable and mobile collecting of multiple parameters farmland information, such as chlorophyll content of crop leaves, air temperature, air humidity, and light intensity. UM220-III (Unicore Communication Inc., Beijing, China) is used to realize the positioning based on BDS/GPS (BeiDou Navigation Satellite System, BDS/Global Positioning System, GPS) dual-mode navigation and positioning system, and the CDMA (Code Division Multiple Access, CDMA) wireless communication module is adopted to realize the real-time remote transmission. The portable multi-function farmland information collection system is real-time, accurate, and easy to use to collect farmland information and multiple information parameters of crops.

  18. A Portable Farmland Information Collection System with Multiple Sensors

    PubMed Central

    Zhang, Jianfeng; Hu, Jinyang; Huang, Lvwen; Zhang, Zhiyong; Ma, Yimian

    2016-01-01

    Precision agriculture is the trend of modern agriculture, and it is also one of the important ways to realize the sustainable development of agriculture. In order to meet the production requirements of precision agriculture—efficient use of agricultural resources, and improving the crop yields and quality—some necessary field information in crop growth environment needs to be collected and monitored. In this paper, a farmland information collection system is developed, which includes a portable farmland information collection device based on STM32 (a 32-bit comprehensive range of microcontrollers based on ARM Crotex-M3), a remote server and a mobile phone APP. The device realizes the function of portable and mobile collecting of multiple parameters farmland information, such as chlorophyll content of crop leaves, air temperature, air humidity, and light intensity. UM220-III (Unicore Communication Inc., Beijing, China) is used to realize the positioning based on BDS/GPS (BeiDou Navigation Satellite System, BDS/Global Positioning System, GPS) dual-mode navigation and positioning system, and the CDMA (Code Division Multiple Access, CDMA) wireless communication module is adopted to realize the real-time remote transmission. The portable multi-function farmland information collection system is real-time, accurate, and easy to use to collect farmland information and multiple information parameters of crops. PMID:27782076

  19. 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

  20. 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.

  1. 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.

  2. 33 CFR 165.835 - Security Zone; Port of Mobile, Mobile Ship Channel, Mobile, AL.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 33 Navigation and Navigable Waters 2 2010-07-01 2010-07-01 false Security Zone; Port of Mobile, Mobile Ship Channel, Mobile, AL. 165.835 Section 165.835 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) PORTS AND WATERWAYS SAFETY REGULATED NAVIGATION AREAS AND LIMITED ACCESS AREAS Specific Regulated...

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

    PubMed Central

    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. PMID:24199118

  4. 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.

  5. Accessibility and utilization patterns of a mobile medical clinic among vulnerable populations.

    PubMed

    Gibson, Britton A; Ghosh, Debarchana; Morano, Jamie P; Altice, Frederick L

    2014-07-01

    We mapped mobile medical clinic (MMC) clients for spatial distribution of their self-reported locations and travel behaviors to better understand health-seeking and utilization patterns of medically vulnerable populations in Connecticut. Contrary to distance decay literature, we found that a small but significant proportion of clients was traveling substantial distances to receive repeat care at the MMC. Of 8404 total clients, 90.2% lived within 5 miles of a MMC site, yet mean utilization was highest (5.3 visits per client) among those living 11-20 miles of MMCs, primarily for those with substance use disorders. Of clients making >20 visits, 15.0% traveled >10 miles, suggesting that a significant minority of clients traveled to MMC sites because of their need-specific healthcare services, which are not only free but available at an acceptable and accommodating environment. The findings of this study contribute to the important research on healthcare utilization among vulnerable population by focusing on broader dimensions of accessibility in a setting where both mobile and fixed healthcare services coexist. Copyright © 2014 Elsevier Ltd. All rights reserved.

  6. A comparison of usability factors of four mobile devices for accessing healthcare information by adolescents.

    PubMed

    Sheehan, B; Lee, Y; Rodriguez, M; Tiase, V; Schnall, R

    2012-01-01

    Mobile health (mHealth) is a growing field aimed at developing mobile information and communication technologies for healthcare. Adolescents are known for their ubiquitous use of mobile technologies in everyday life. However, the use of mHealth tools among adolescents is not well described. We examined the usability of four commonly used mobile devices (an iPhone, an Android with touchscreen keyboard, an Android with built-in keyboard, and an iPad) for accessing healthcare information among a group of urban-dwelling adolescents. Guided by the FITT (Fit between Individuals, Task, and Technology) framework, a thinkaloud protocol was combined with a questionnaire to describe usability on three dimensions: 1) task-technology fit; 2) individual-technology fit; and 3) individual-task fit. For task-technology fit, we compared the efficiency, and effectiveness of each of the devices tested and found that the iPhone was the most usable had the fewest errors and prompts and had the lowest mean overall task time For individual-task fit, we compared efficiency and learnability measures by website tasks and found no statistically significant effect on tasks steps, task time and number of errors. Following our comparison of success rates by website tasks, we compared the difference between two mobile applications which were used for diet tracking and found statistically significant effect on tasks steps, task time and number of errors. For individual-technology fit, interface quality was significantly different across devices indicating that this is an important factor to be considered in developing future mobile devices. All of our users were able to complete all of the tasks, however the time needed to complete the tasks was significantly different by mobile device and mHealth application. Future design of mobile technology and mHealth applications should place particular importance on interface quality.

  7. 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.

  8. Optimal power allocation and joint source-channel coding for wireless DS-CDMA visual sensor networks

    NASA Astrophysics Data System (ADS)

    Pandremmenou, Katerina; Kondi, Lisimachos P.; Parsopoulos, Konstantinos E.

    2011-01-01

    In this paper, we propose a scheme for the optimal allocation of power, source coding rate, and channel coding rate for each of the nodes of a wireless Direct Sequence Code Division Multiple Access (DS-CDMA) visual sensor network. The optimization is quality-driven, i.e. the received quality of the video that is transmitted by the nodes is optimized. The scheme takes into account the fact that the sensor nodes may be imaging scenes with varying levels of motion. Nodes that image low-motion scenes will require a lower source coding rate, so they will be able to allocate a greater portion of the total available bit rate to channel coding. Stronger channel coding will mean that such nodes will be able to transmit at lower power. This will both increase battery life and reduce interference to other nodes. Two optimization criteria are considered. One that minimizes the average video distortion of the nodes and one that minimizes the maximum distortion among the nodes. The transmission powers are allowed to take continuous values, whereas the source and channel coding rates can assume only discrete values. Thus, the resulting optimization problem lies in the field of mixed-integer optimization tasks and is solved using Particle Swarm Optimization. Our experimental results show the importance of considering the characteristics of the video sequences when determining the transmission power, source coding rate and channel coding rate for the nodes of the visual sensor network.

  9. 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

  10. 49 CFR 38.83 - Mobility aid accessibility.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... wheelchair or mobility aid users to reach areas, each with a minimum clear floor space of 48 inches by 30 inches, which do not unduly restrict passenger flow. Space to accommodate wheelchairs and mobility aids may be provided within the normal area used by standees and designation of specific spaces is not...

  11. 49 CFR 38.83 - Mobility aid accessibility.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... wheelchair or mobility aid users to reach areas, each with a minimum clear floor space of 48 inches by 30 inches, which do not unduly restrict passenger flow. Space to accommodate wheelchairs and mobility aids may be provided within the normal area used by standees and designation of specific spaces is not...

  12. 49 CFR 38.83 - Mobility aid accessibility.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... wheelchair or mobility aid users to reach areas, each with a minimum clear floor space of 48 inches by 30 inches, which do not unduly restrict passenger flow. Space to accommodate wheelchairs and mobility aids may be provided within the normal area used by standees and designation of specific spaces is not...

  13. 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.

  14. UTC Time Transfer for High Frequency Trading Using IS-95 CDMA Base Station Transmissions and IEEE-1588 Precision Time Protocol

    DTIC Science & Technology

    2010-11-01

    CDMA base stations are each synchronized by GPS receivers, they provide an indirect link to GPS system time and UTC time . The major stock...antenna synchronizes the Local Area Network (LAN) to within 10 microseconds of UTC using the IEEE-1588 Precision Time Protocol (PTP). This is an...activities. Understanding and measuring latency on the LAN is key to the success of HFTs. Without precise time synchronization below 1 millisecond

  15. 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…

  16. Are We Sure That Mobile Health Is Really Mobile? An examination of mobile device use during two remotely-delivered weight loss interventions

    PubMed Central

    Turner-McGrievy, Gabrielle M.; Tate, Deborah F.

    2014-01-01

    Background The “m” in mHealth is often thought of as the ability to receive health information and monitor behaviors on the go. Little is known about how people actually use mobile vs. traditional access methods and if access method affects engagement and health outcomes. Methods This study examines the 3-month outcomes of two mobile weight loss interventions (Pounds Off Digitally (POD) and mobile POD (mPOD)) where participants were required to own a mobile device for study entry and received weight loss information via podcast. Only participants in both studies who were randomized to receive the same theory-based podcast (TBP) were used in this analysis. In POD, 41 participants were randomized to the TBP condition (37 to a control not included in this analyses). In mPOD, 49 participants were randomized to the TBP (n=49) and 47 to the TBP+mobile group (a self-monitoring app and Twitter app for social support). The goal of this study is to examine how participants accessed study components and to examine how type of device impacts engagement and weight loss. Results Examining data from both studies in aggregate, despite a mobile delivery method, 58% of participants reported using a non-mobile device to access the majority of the podcasts (desktop computers), 76% accessed the podcasts mostly at their home or work, and 62% were mainly non-mobile (e.g., sitting at work) when listening. Examining objective download data for mPOD, 49% of downloads (2889/5944) originated from non-mobile delivery methods vs. mobile platforms (3055/5944). At 3 months, 55% of Twitter posts originated from the website (n=665 posts) vs. a mobile app (n=540; 45%). There was no difference in the number of podcasts participants reported listening to by device. There were more Twitter posts by mobile app users (51±11) than Twitter website users (23±6; p<0.05). There was a trend (p=0.055) in greater weight loss among mobile users for podcasts (−3.5±0.5%) as compared to non-mobile users (

  17. Are we sure that Mobile Health is really mobile? An examination of mobile device use during two remotely-delivered weight loss interventions.

    PubMed

    Turner-McGrievy, Gabrielle M; Tate, Deborah F

    2014-05-01

    The "m" in mHealth is often thought of as the ability to receive health information and monitor behaviors on the go. Little is known about how people actually use mobile vs. traditional access methods and if access method affects engagement and health outcomes. This study examines the 3-month outcomes of two mobile weight loss interventions (Pounds Off Digitally (POD) and mobile POD (mPOD)) where participants were required to own a mobile device for study entry and received weight loss information via podcast. Only participants in both studies who were randomized to receive the same theory-based podcast (TBP) were used in this analysis. In POD, 41 participants were randomized to the TBP condition (37 to a control not included in this analyses). In mPOD, 49 participants were randomized to the TBP (n=49) and 47 to the TBP+mobile group (a self-monitoring app and Twitter app for social support). The goal of this study is to examine how participants accessed study components and to examine how type of device impacts engagement and weight loss. Examining data from both studies in aggregate, despite a mobile delivery method, 58% of participants reported using a non-mobile device to access the majority of the podcasts (desktop computers), 76% accessed the podcasts mostly at their home or work, and 62% were mainly non-mobile (e.g., sitting at work) when listening. Examining objective download data for mPOD, 49% of downloads (2889/5944) originated from non-mobile delivery methods vs. mobile platforms (3055/5944). At 3 months, 55% of Twitter posts originated from the website (n=665 posts) vs. a mobile app (n=540; 45%). There was no difference in the number of podcasts participants reported listening to by device. There were more Twitter posts by mobile app users (51±11) than Twitter website users (23±6, p<0.05). There was a trend (p=0.055) in greater weight loss among mobile users for podcasts (-3.5±0.5%) as compared to non-mobile users (-2.5±0.5%). Weight loss was

  18. Developing and Evaluating a Technology Enhanced Interaction Framework and Method That Can Enhance the Accessibility of Mobile Learning

    ERIC Educational Resources Information Center

    Angkananon, Kewalin; Wald, Mike; Gilbert, Lester

    2014-01-01

    This paper focuses on the development and evaluation of a Technology Enhanced Interaction Framework and Method that can help with designing accessible mobile learning interactions involving disabled people. This new framework and method were developed to help design technological support for communication and interactions between people,…

  19. FD/DAMA Scheme For Mobile/Satellite Communications

    NASA Technical Reports Server (NTRS)

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

    1992-01-01

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

  20. Accessibility for persons with mobility impairments within an informal trading site: A case study on the markets of Warwick, South Africa

    PubMed Central

    Koch, Helga Elke; Anderson, Jassmine; Ghela, Prashika; Govender, Perusha; Hoosen, Nausheena; Khan, Halima

    2014-01-01

    Background There are a number of informal trading sites across cities in sub-Saharan Africa, of which the markets of Warwick is one example. Since the informal economy is an important contributor to a city’s economy as well as a source of employment, it is important for these sites to be accessible for all persons. Whilst the South African government has put structures in place to identify and remove environmental barriers in order to meet the individual needs of persons with mobility impairments and improve their quality of life, persons with mobility impairments still face barriers and restricting environments that prevent them from participating in society and its social and economic activities. Objectives This case study aimed at exploring accessibility within the markets of Warwick for persons with mobility impairments by an ergonomic assessment, augmented by voices of participants within the market. Method A qualitative, instrumental, single case study design was utilised with purposive sampling of the markets of Warwick as the study setting. Multiple sources of data were gathered, such as semi-structured interviews, direct observations of an environmental survey supported by photographs, and the authors’ review of relevant documents. Transcriptions were analysed using NVivo 10 software programme with inductive coding. Results Whilst policies have been in place since 1996 to adjust infrastructure, the markets of Warwick still remain inaccessible to persons with mobility impairments and do not meet the standardised infrastructural design. Conclusion The findings of this study may offer a significant understanding of the complexity of accessibility within an informal trading site and create an awareness of the limitations this has for persons with mobility impairments. Additionally, these findings may assist in effecting a positive change in terms of the infrastructure of the Markets and in continuous advocating for the rights of persons with all

  1. Rethinking Mobile Telephony with the IMP

    DTIC Science & Technology

    2011-01-01

    in the telephony industry, and portions of it such as SS7 or SCTP signaling are packet-switched, deployed mobile telephony access infrastructure is...deployment of wireless LAN technology raises the question of how a mobile telephony system might instead be architected to use wireless LAN access ...and wireless access points has made universal Internet access increasingly convenient. There are clearly barriers to this vision of accessing a

  2. Healthcare access and mobility between the UK and other European Union states: an 'implementation surplus'.

    PubMed

    Sheaff, R

    1997-12-01

    European Union (EU) policy on mobility requires ensuring healthcare access for EU residents who travel between EU states. This case-study investigates how this policy has been implemented in respect of EU visitors to the UK. EU visitors to the UK have similar access to 'immediately needed' National Health Service (NHS) healthcare to UK residents. For non-urgent healthcare, the NHS has official systems to discourage 'medical tourism' and divert such patients to the private sector or to reclaim the costs of NHS hospital treatment for EU visitors. Yet these official systems contrast with the flexibility and liberality of actual NHS practice towards EU visitors. Research on health policy implementation mostly examines reasons for 'implementation failure'. However, the present study indicates a health policy being implemented more fully than policy-makers may have anticipated. In the case of healthcare access for EU visitors to the UK, an implementation surplus is evident rather than an implementation deficit.

  3. Utility of routine postoperative visit after appendectomy and cholecystectomy with evaluation of mobile technology access in an urban safety net population.

    PubMed

    Chen, Diane W; Davis, Rachel W; Balentine, Courtney J; Scott, Aaron R; Gao, Yue; Tapia, Nicole M; Berger, David H; Suliburk, James W

    2014-08-01

    The value of routine postoperative visits after general surgery remains unclear. The objective of this study was to evaluate the utility of routine postoperative visits after appendectomy and cholecystectomy and to determine access to mobile technology as an alternative platform for follow-up. Retrospective review of 219 appendectomies and 200 cholecystectomies performed at a safety net hospital. One patient underwent both surgeries. Patient demographics, duration of clinic visit, and need for additional imaging, tests or readmissions were recorded. Access to mobile technology was surveyed by a validated questionnaire. Of 418 patients, 84% percent completed a postoperative visit. At follow-up, 58 patients (14%) required 70 interventions, including staple removal (16, 23%), suture removal (4, 6%), drain removal (8, 11%), additional follow-up (20, 28%), medication action (16, 21%), additional imaging (3, 4%), and readmission (1, 1%). Occupational paperwork (62) and nonsurgical clinic referrals (28) were also performed. Average check-in to check-out time was 100 ± 54 min per patient. One intervention was performed for every 7.8 h of time in the clinic. Additionally, 88% of the surveyed population reported access to cell phone technology, and 69% of patients <40 y had smartphone access. Routine in-person follow-up after surgery consumes significant time and resources for patients and healthcare systems but has little impact on patient care. Most of the work done in the clinic is administrative and could be completed using mobile technology, which is pervasive in our population. Copyright © 2014 Elsevier Inc. All rights reserved.

  4. 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.

  5. 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…

  6. Accurate Bit Error Rate Calculation for Asynchronous Chaos-Based DS-CDMA over Multipath Channel

    NASA Astrophysics Data System (ADS)

    Kaddoum, Georges; Roviras, Daniel; Chargé, Pascal; Fournier-Prunaret, Daniele

    2009-12-01

    An accurate approach to compute the bit error rate expression for multiuser chaosbased DS-CDMA system is presented in this paper. For more realistic communication system a slow fading multipath channel is considered. A simple RAKE receiver structure is considered. Based on the bit energy distribution, this approach compared to others computation methods existing in literature gives accurate results with low computation charge. Perfect estimation of the channel coefficients with the associated delays and chaos synchronization is assumed. The bit error rate is derived in terms of the bit energy distribution, the number of paths, the noise variance, and the number of users. Results are illustrated by theoretical calculations and numerical simulations which point out the accuracy of our approach.

  7. Framework for power and activity factor allocation in a multiclass CDMA system

    NASA Astrophysics Data System (ADS)

    Wu, Xinzhou; Srikant, Rayadurgam

    2001-07-01

    We consider a multimedia CDMA uplink where there are multiple classes of users with different Quality-of-Service (QoS) requirements. Each user is modeled as an ON-OFF source, where in the ON state, the user transmits a fixed number of bits in each time slot and in the OFF state, the user is silent. The probability of being in the ON state, known as the activity factor, could be different for different users. Assuming a constant channel gain, we first characterize the set of transmit power levels, activity factors and number of users in each class that can be supported by a system with a given spreading gain under the constraint that each user's QoS requirement must be met. Using this characterization, we then present a utility function-based algorithm for choosing the activity factors of elastic users in the network.

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

    NASA Astrophysics Data System (ADS)

    Devieux, Carrie L.

    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.

  9. 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.

  10. 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.

  11. Accessibility of sports facilities for persons with reduced mobility and assessment of their motivation for practice.

    PubMed

    Sá, Maria Manuel; Azevedo, Rui; Martins, Maria Cristina; Machado, Osvaldo; Tavares, João

    2012-01-01

    This study aims to create awareness, both within the scientific community and among providers of sports facilities, for individuals with impaired or reduced mobility, promoting the development of technical solutions that allow greater autonomy and social integration of people with disabilities. The purpose of this work is, on the one hand, to evaluate the accessibility of sports facilities for people with reduced mobility and, on the other hand, to investigate why this user group has such low rates of participation in sporting activities. Firstly, using the Portuguese norms and legislation transcribed from European Community directives, a check list was created comprising all the items that sports facilities should abide by in order to provide accessibility and safety to people with reduced mobility. Another questionnaire was designed aimed at this user group, with questions pertaining to their desire and ability to use sports facilities. This questionnaire was distributed in Portugal, in the greater metropolitan area of Porto, to users of Rehabilitation Centres and Physiotherapy Clinics. The results obtained from the check-list showed the compliances and non-compliances of the respective sports facilities, proving that many barriers preventing the participation of people with reduced mobility still exist. Twenty-four people with permanent impairment of the lower extremities (paraplegia) answered the questionnaire pertaining to the desire and ability to perform physical activity. Two individuals (8%) had sporting activities available to them in their area of residence and only five (21%) performed any physical activity. The main reason given for not taking part in any activity was the lack of adapted sports facilities. All the participants felt that taking part in sports is beneficial. The benefits stated were: general well-being and development of the psychomotor component (e.g. coordination, balance, body posture), of physical condition (e.g. strength, resistance

  12. Ad Hoc Access Gateway Selection Algorithm

    NASA Astrophysics Data System (ADS)

    Jie, Liu

    With the continuous development of mobile communication technology, Ad Hoc access network has become a hot research, Ad Hoc access network nodes can be used to expand capacity of multi-hop communication range of mobile communication system, even business adjacent to the community, improve edge data rates. For mobile nodes in Ad Hoc network to internet, internet communications in the peer nodes must be achieved through the gateway. Therefore, the key Ad Hoc Access Networks will focus on the discovery gateway, as well as gateway selection in the case of multi-gateway and handover problems between different gateways. This paper considers the mobile node and the gateway, based on the average number of hops from an average access time and the stability of routes, improved gateway selection algorithm were proposed. An improved gateway selection algorithm, which mainly considers the algorithm can improve the access time of Ad Hoc nodes and the continuity of communication between the gateways, were proposed. This can improve the quality of communication across the network.

  13. 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.

  14. Access to mobile communications by older people.

    PubMed

    Nguyen, Toan; Irizarry, Carol; Garrett, Rob; Downing, Andrew

    2015-06-01

    To investigate how older people effectively identify, select and learn to use mobile communications technologies to enhance communication and safety, and support independent living. One hundred and fifty-three older South Australians participated in a purpose-designed survey questionnaire. Older people relied on family and friends for information and advice (76%), and their children's assistance with buying (45%) and learning to use (48%) new technology. The most preferred learning method was face-to-face training (56%). Less than half (44%) were interested in trying out new designs/applications, functions and capabilities that could assist with independent living. The highest need was for personal security and emergencies (88%). Findings suggest that the family and friends of older people play an important role in identifying, selecting and learning to use mobile communication technologies. The safety and emergency capabilities of mobile communications technologies were more important than having functions that could assist with independent living. © 2014 ACOTA.

  15. 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.

  16. TissueWikiMobile: an Integrative Protein Expression Image Browser for Pathological Knowledge Sharing and Annotation on a Mobile Device

    PubMed Central

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

    2016-01-01

    Doctors need fast and convenient access to medical data. This motivates the use of mobile devices for knowledge retrieval and sharing. We have developed TissueWikiMobile 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 TissueWikiMobile, 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 TissueWikiMobile to access important biomedical data without losing mobility. TissueWikiMobile 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. PMID:27532057

  17. Code-division multiple-access protocol for active RFID systems

    NASA Astrophysics Data System (ADS)

    Mazurek, Gustaw; Szabatin, Jerzy

    2008-01-01

    Most of the Radio Frequency Identification (RFID) systems operating in HF and UHF bands employ narrowband modulations (FSK or ASK) with Manchester coding. However, these simple transmission schemes are vulnerable to narrowband interference (NBI) generated by other radio systems working in the same frequency band, and also suffer from collision problem and need special anti-collision procedures. This becomes especially important when operating in a noisy, crowded industrial environment. In this paper we show the performance of RFID system with DS-CDMA transmission in comparison to a standard system with FSK modulation defined in ISO 18000-7. Our simulation results show that without any bandwidth expansion the immunity against NBI can be improved by 8 dB and the system capacity can be 7 times higher when using DS-CDMA transmission instead of FSK modulation with Manchester coding.

  18. Creating widely accessible spatial interfaces: mobile VR for managing persistent pain.

    PubMed

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

    2013-01-01

    Using widely accessible VR technologies, researchers have implemented a series of multimodal spatial interfaces and virtual environments. The results demonstrate the degree to which we can now use low-cost (for example, mobile-phone based) VR environments to create rich virtual experiences involving motion sensing, physiological inputs, stereoscopic imagery, sound, and haptic feedback. Adapting spatial interfaces to these new platforms can open up exciting application areas for VR. In this case, the application area was in-home VR therapy for patients suffering from persistent pain (for example, arthritis and cancer pain). For such therapy to be successful, a rich spatial interface and rich visual aesthetic are particularly important. So, an interdisciplinary team with expertise in technology, design, meditation, and the psychology of pain collaborated to iteratively develop and evaluate several prototype systems. The video at http://youtu.be/mMPE7itReds demonstrates how the sine wave fitting responds to walking motions, for a walking-in-place application.

  19. 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…

  20. 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…

  1. 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

  2. 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.

  3. 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.

  4. 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.

  5. Utilization of mobile phones for accessing menstrual regulation services among low-income women in Bangladesh: a qualitative analysis.

    PubMed

    Messinger, Chelsea Jordan; Mahmud, Ilias; Kanan, Sushama; Jahangir, Yamin Tauseef; Sarker, Malabika; Rashid, Sabina Faiz

    2017-01-14

    As many as one-third of all pregnancies in Bangladesh are unplanned, with nearly one-half of these pregnancies ending in either menstrual regulation (MR) or illegal clandestine abortion. Although MR is provided free of charge, or at a nominal cost, through the public sector and various non-profits organizations, many women face barriers in accessing safe, affordable MR and post-MR care. Mobile health (mHealth) services present a promising platform for increasing access to MR among low-income women at risk for clandestine abortion. We sought to investigate the knowledge, attitudes and practices regarding mHealth of both MR clients and formal and informal sexual and reproductive healthcare providers in urban and rural low-income settlements in Bangladesh. A total of 58 interviews were conducted with MR clients, formal MR providers, and informal MR providers in four low-income settlements in the Dhaka and Sylhet districts of Bangladesh. Interview data was coded and qualitatively analysed for themes using standard qualitative research practices. Our findings suggest that low-income MR clients in Bangladesh have an inadequate understanding of how to use their mobile phones to obtain health service information or counselling related to MR, and correspondingly low levels of formal or informal mHealth service utilization. Few were aware of any formal mHealth services in place in their communities, despite the fact that providers stated that hotlines were available. Overall, MR clients expressed positive opinions of mHealth services as a means of improving women's access to affordable and timely MR. Formal and informal MR providers believed that mobile phones had benefits with respect to information dissemination and making appointments, but emphasized the necessity of in-person consultations for effective sexual and reproductive healthcare. We report low utilization yet high acceptability of mHealth services among low-income MR clients in Bangladesh. Expanding formal and

  6. Libraries and the Mobile Web

    ERIC Educational Resources Information Center

    Hanson, Cody

    2011-01-01

    In 2011, cell phones and mobile devices are ubiquitous. The vast majority of Americans now own cell phones, and over half of them have mobile access to the Internet through a phone or other mobile device. For libraries to stay relevant, they must be able to offer content and services through the mobile web. In this issue of "Library Technology…

  7. On Performance of Linear Multiuser Detectors for Wireless Multimedia Applications

    NASA Astrophysics Data System (ADS)

    Agarwal, Rekha; Reddy, B. V. R.; Bindu, E.; Nayak, Pinki

    In this paper, performance of different multi-rate schemes in DS-CDMA system is evaluated. The analysis of multirate linear multiuser detectors with multiprocessing gain is analyzed for synchronous Code Division Multiple Access (CDMA) systems. Variable data rate is achieved by varying the processing gain. Our conclusion is that bit error rate for multirate and single rate systems can be made same with a tradeoff with number of users in linear multiuser detectors.

  8. 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…

  9. Mobile health clinics in the era of reform.

    PubMed

    Hill, Caterina F; Powers, Brian W; Jain, Sachin H; Bennet, Jennifer; Vavasis, Anthony; Oriol, Nancy E

    2014-03-01

    Despite the role of mobile clinics in delivering care to the full spectrum of at-risk populations, the collective impact of mobile clinics has never been assessed. This study characterizes the scope of the mobile clinic sector and its impact on access, costs, and quality. It explores the role of mobile clinics in the era of delivery reform and expanded insurance coverage. A synthesis of observational data collected through Mobile Health Map and published literature related to mobile clinics. Analysis of data from the Mobile Health Map Project, an online platform that aggregates data on mobile health clinics in the United States, supplemented by a comprehensive literature review. Mobile clinics represent an integral component of the healthcare system that serves vulnerable populations and promotes high-quality care at low cost. There are an estimated 1500 mobile clinics receiving 5 million visits nationwide per year. Mobile clinics improve access for vulnerable populations, bolster prevention and chronic disease management, and reduce costs. Expanded coverage and delivery reform increase opportunities for mobile clinics to partner with hospitals, health systems, and insurers to improve care and lower costs. Mobile clinics have a critical role to play in providing high-quality, low-cost care to vulnerable populations. The postreform environment, with increasing accountability for population health management and expanded access among historically underserved populations, should strengthen the ability for mobile clinics to partner with hospitals, health systems, and payers to improve care and lower costs.

  10. 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.

  11. 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.

  12. 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.

  13. 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…

  14. Growth of mobile applications in dermatology - 2017 update.

    PubMed

    Flaten, Hania K; St Claire, Chelsea; Schlager, Emma; Dunnick, Cory A; Dellavalle, Robert P

    2018-02-15

    More than 80% of households in the US have a smartphone. Growth of mobile applications (apps) has grown in parallel with access to smartphones. Mobile health apps are used in medical fields, including dermatology. These apps allow patients to access information regarding dermatology conditions as well as access physicians via teledermatology. To analyze changes in number of dermatology mobile apps since 2014 and discuss benefits and drawbacks of mobile application growth to dermatology. Apple, Android, and Windows were queried for dermatology-related apps. The apps were categorized by purpose and compared to previously published data to assess growth and change in dermatology apps. A total of 526 dermatology mobile apps were found corresponding to an 80.8% growth in dermatology apps since 2014. The market share of teledermatology increased from 11.0% in 2014 to 20.1% in 2017. Dermatology apps continue to grow at a comparable pace to general app growth. Teledermatology apps experienced significant growth from 2014 to 2017. This growth has allowed time-efficient and cost-effective access to dermatologists, especially in rural areas. The growth of dermatology apps targeting patients allows for patient autonomy but also can result in access to inaccurate information regarding dermatology conditions.

  15. 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…

  16. Second generation accessible pedestrian systems.

    DOT National Transportation Integrated Search

    2014-09-01

    The Americans with Disabilities Act of 1990 has had a great impact on the implementation of Accessible Pedestrian Systems that target accessible and safety : impediments faced by pedestrians with mobility and visual impairments. Intersection geometri...

  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. Multi-Mode, Multi-Antenna Software Defined Radar for Adaptive Tracking and Identification of Targets in Urban Environments

    DTIC Science & Technology

    2011-10-31

    designs with code division multiple access ( CDMA ). Analog chirp filters were used to produce an up-chirp, which is used as a radar waveform, coupled with...signals. A potential shortcoming of CDMA techniques is that the addition of two signals will result in a non-constant amplitude signal which will be...of low-frequency A/ Ds . As an example for a multiple carrier signal all the received signals from the multiple carriers are aliased onto the

  19. ML Crew Access Arm Move

    NASA Image and Video Library

    2017-11-10

    A heavy-load transport truck carries the Orion crew access arm along the NASA Causeway east toward State Road 3 at NASA's Kennedy Space Center in Florida. The access arm will be moved to the mobile launcher (ML) near the Vehicle Assembly Building at the center. The crew access arm will be installed at about the 274-foot level on the mobile launcher tower. It will rotate from its retracted position and interface with the Orion crew hatch location to provide entry to the Orion crew module. The Ground Systems Development and Operations Program is overseeing installation of umbilicals and launch accessories on the ML tower to prepare for Exploration Mission-1.

  20. An implementation of wireless medical image transmission system on mobile devices.

    PubMed

    Lee, SangBock; Lee, Taesoo; Jin, Gyehwan; Hong, Juhyun

    2008-12-01

    The advanced technology of computing system was followed by the rapid improvement of medical instrumentation and patient record management system. The typical examples are hospital information system (HIS) and picture archiving and communication system (PACS), which computerized the management procedure of medical records and images in hospital. Because these systems were built and used in hospitals, doctors out of hospital have problems to access them immediately on emergent cases. To solve these problems, this paper addressed the realization of system that could transmit the images acquired by medical imaging systems in hospital to the remote doctors' handheld PDA's using CDMA cellular phone network. The system consists of server and PDA. The server was developed to manage the accounts of doctors and patients and allocate the patient images to each doctor. The PDA was developed to display patient images through remote server connection. To authenticate the personal user, remote data access (RDA) method was used in PDA accessing the server database and file transfer protocol (FTP) was used to download patient images from the remove server. In laboratory experiments, it was calculated to take ninety seconds to transmit thirty images with 832 x 488 resolution and 24 bit depth and 0.37 Mb size. This result showed that the developed system has no problems for remote doctors to receive and review the patient images immediately on emergent cases.

  1. 49 CFR 38.23 - Mobility aid accessibility.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... in width. When the platform is at vehicle floor height with the inner barrier (if applicable) down or... accessible entrance as practicable and shall have a clear floor area of 30 inches by 48 inches. Such space shall adjoin, and may overlap, an access path. Not more than 6 inches of the required clear floor space...

  2. 49 CFR 38.23 - Mobility aid accessibility.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... in width. When the platform is at vehicle floor height with the inner barrier (if applicable) down or... accessible entrance as practicable and shall have a clear floor area of 30 inches by 48 inches. Such space shall adjoin, and may overlap, an access path. Not more than 6 inches of the required clear floor space...

  3. 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.

  4. Going Mobile: How Mobile Personal Health Records Can Improve Health Care During Emergencies

    PubMed Central

    Ravi, Sanjana

    2014-01-01

    Personal health records (PHRs), in contrast to electronic health records (EHRs) or electronic medical records (EMRs), are health records in which data are accessible to patients and not just providers. In recent years, many systems have enabled PHRs to be available in a mobile format. Mobile PHRs (mPHRs) allow patients to access health information via the Internet or telecommunication devices, such as mobile phones, personal digital assistants, and tablet computers. mPHRs have the potential to help patients and providers identify medical conditions and prescriptions from numerous locations, which may minimize medical errors and identify improvements to health behaviors during emergencies, when patients present to a new provider, or EHRs are not accessible. Despite their benefits, numerous challenges inhibit the adoption and further development of mPHRs, including integration into overall health technology infrastructure and legal and security concerns. This paper identifies the benefits of mPHRs during emergencies and the remaining challenges impeding full adoption and use, and provides recommendations to federal agencies to enhance support and use of mPHRs. PMID:25098942

  5. Low vision and mobility scooters: the experiences of individuals with low vision who use mobility scooters.

    PubMed

    McMullan, Keri S; Butler, Mary

    2018-05-09

    Older adults with low vision are a growing population with rehabilitation needs including support with community mobility to enable community participation. Some older adults with low vision choose to use mobility scooters to mobilize within their community, but there is limited research about the use by people with low vision. This paper describes a pilot study and asks the question: what are the experiences of persons with low vision who use mobility scooters? This study gathered the experiences of four participants with low vision, aged 51 and over, who regularly use mobility scooters. Diverse methods were used including a go-along, a semi-structured interview and a new measure of functional vision for mobility called the vision-related outcomes in orientation and mobility (VROOM). Four themes were found to describe experiences: autonomy and well-being, accessibility, community interactions and self-regulation. Discussion and implications: This study was a pilot for a larger study examining self-regulation in scooter users. However, as roles emerge for health professionals and scooters, the findings also provide evidence to inform practice, because it demonstrates the complex meaning and influences on performance involved in low vision mobility scooter use. Implications for rehabilitation Scooter use supports autonomy and well-being and community connections for individuals with both mobility and visual impairments. Low vision scooter users demonstrate self-regulation of their scooter use to manage both their visual and environmental limitations. Issues of accessibility experienced by this sample affect a wider community of footpath users, emphasizing the need for councils to address inadequate infrastructure. Rehabilitators can support their low vision clients' scooter use by acknowledging issues of accessibility and promoting self-regulation strategies to manage risks and barriers.

  6. ML Crew Access Arm Move

    NASA Image and Video Library

    2017-11-10

    A heavy-load transport truck carrying the Orion crew access arm passes the Vehicle Assembly Building on its way to the mobile launcher at NASA's Kennedy Space Center in Florida. The access arm will be installed at about the 274-foot level on the mobile launcher tower. It will rotate from its retracted position and interface with the Orion crew hatch location to provide entry to the Orion crew module. The Ground Systems Development and Operations Program is overseeing installation of umbilicals and launch accessories on the ML tower to prepare for Exploration Mission-1.

  7. ML Crew Access Arm Move

    NASA Image and Video Library

    2017-11-10

    A heavy-load transport truck carrying the Orion crew access arm makes its way toward the mobile launcher (ML) at NASA's Kennedy Space Center in Florida. The crew access arm will be installed at about the 274-foot level on the mobile launcher tower. It will rotate from its retracted position and interface with the Orion crew hatch location to provide entry to the Orion crew module. The Ground Systems Development and Operations Program is overseeing installation of umbilicals and launch accessories on the ML tower to prepare for Exploration Mission-1.

  8. ML Crew Access Arm Move

    NASA Image and Video Library

    2017-11-10

    A heavy-load transport truck carrying the Orion crew access arm nears the mobile launcher (ML) at NASA's Kennedy Space Center in Florida. The crew access arm will be installed at about the 274-foot level on the mobile launcher tower. It will rotate from its retracted position and interface with the Orion crew hatch location to provide entry to the Orion crew module. The Ground Systems Development and Operations Program is overseeing installation of umbilicals and launch accessories on the ML tower to prepare for Exploration Mission-1.

  9. Experiences and Perceptions of Adults Accessing Publicly Available Nutrition Behavior-Change Mobile Apps for Weight Management.

    PubMed

    Lieffers, Jessica R L; Arocha, Jose F; Grindrod, Kelly; Hanning, Rhona M

    2018-02-01

    Nutrition mobile apps have become accessible and popular weight-management tools available to the general public. To date, much of the research has focused on quantitative outcomes with these tools (eg, weight loss); little is known about user experiences and perceptions of these tools when used outside of a research trial environment. Our aim was to understand the experiences and perceptions of adult volunteers who have used publicly available mobile apps to support nutrition behavior change for weight management. We conducted one-on-one semi-structured interviews with individuals who reported using nutrition mobile apps for weight management outside of a research setting. Twenty-four healthy adults (n=19 females, n=5 males) who had used publicly available nutrition mobile apps for weight management for ≥1 week within the past 3 to 4 months were recruited from the community in southern Ontario and Edmonton, Canada, using different methods (eg, social media, posters, and word of mouth). Interviews were audiorecorded, transcribed verbatim, and transcripts were verified against recordings. Data were coded inductively and organized into categories using NVivo, version 10 (QSR International). Participants used nutrition apps for various amounts of time (mean=approximately 14 months). Varied nutrition apps were used; however, MyFitnessPal was the most common. In the interviews, the following four categories of experiences with nutrition apps became apparent: food data entry (database, data entry methods, portion size, and complex foods); accountability, feedback, and progress (goal setting, accountability, monitoring, and feedback); technical and app-related factors; and personal factors (self-motivation, privacy, knowledge, and obsession). Most participants used apps without professional or dietitian support. This work reveals that numerous factors affect use and ongoing adherence to use of nutrition mobile apps. These data are relevant to professionals looking to

  10. 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…

  11. Biometrics: Accessibility challenge or opportunity?

    PubMed

    Blanco-Gonzalo, Ramon; Lunerti, Chiara; Sanchez-Reillo, Raul; Guest, Richard Michael

    2018-01-01

    Biometric recognition is currently implemented in several authentication contexts, most recently in mobile devices where it is expected to complement or even replace traditional authentication modalities such as PIN (Personal Identification Number) or passwords. The assumed convenience characteristics of biometrics are transparency, reliability and ease-of-use, however, the question of whether biometric recognition is as intuitive and straightforward to use is open to debate. Can biometric systems make some tasks easier for people with accessibility concerns? To investigate this question, an accessibility evaluation of a mobile app was conducted where test subjects withdraw money from a fictitious ATM (Automated Teller Machine) scenario. The biometric authentication mechanisms used include face, voice, and fingerprint. Furthermore, we employed traditional modalities of PIN and pattern in order to check if biometric recognition is indeed a real improvement. The trial test subjects within this work were people with real-life accessibility concerns. A group of people without accessibility concerns also participated, providing a baseline performance. Experimental results are presented concerning performance, HCI (Human-Computer Interaction) and accessibility, grouped according to category of accessibility concern. Our results reveal links between individual modalities and user category establishing guidelines for future accessible biometric products.

  12. Biometrics: Accessibility challenge or opportunity?

    PubMed Central

    Lunerti, Chiara; Sanchez-Reillo, Raul; Guest, Richard Michael

    2018-01-01

    Biometric recognition is currently implemented in several authentication contexts, most recently in mobile devices where it is expected to complement or even replace traditional authentication modalities such as PIN (Personal Identification Number) or passwords. The assumed convenience characteristics of biometrics are transparency, reliability and ease-of-use, however, the question of whether biometric recognition is as intuitive and straightforward to use is open to debate. Can biometric systems make some tasks easier for people with accessibility concerns? To investigate this question, an accessibility evaluation of a mobile app was conducted where test subjects withdraw money from a fictitious ATM (Automated Teller Machine) scenario. The biometric authentication mechanisms used include face, voice, and fingerprint. Furthermore, we employed traditional modalities of PIN and pattern in order to check if biometric recognition is indeed a real improvement. The trial test subjects within this work were people with real-life accessibility concerns. A group of people without accessibility concerns also participated, providing a baseline performance. Experimental results are presented concerning performance, HCI (Human-Computer Interaction) and accessibility, grouped according to category of accessibility concern. Our results reveal links between individual modalities and user category establishing guidelines for future accessible biometric products. PMID:29565989

  13. Joint Transmitter and Receiver Power Allocation under Minimax MSE Criterion with Perfect and Imperfect CSI for MC-CDMA Transmissions

    NASA Astrophysics Data System (ADS)

    Kotchasarn, Chirawat; Saengudomlert, Poompat

    We investigate the problem of joint transmitter and receiver power allocation with the minimax mean square error (MSE) criterion for uplink transmissions in a multi-carrier code division multiple access (MC-CDMA) system. The objective of power allocation is to minimize the maximum MSE among all users each of which has limited transmit power. This problem is a nonlinear optimization problem. Using the Lagrange multiplier method, we derive the Karush-Kuhn-Tucker (KKT) conditions which are necessary for a power allocation to be optimal. Numerical results indicate that, compared to the minimum total MSE criterion, the minimax MSE criterion yields a higher total MSE but provides a fairer treatment across the users. The advantages of the minimax MSE criterion are more evident when we consider the bit error rate (BER) estimates. Numerical results show that the minimax MSE criterion yields a lower maximum BER and a lower average BER. We also observe that, with the minimax MSE criterion, some users do not transmit at full power. For comparison, with the minimum total MSE criterion, all users transmit at full power. In addition, we investigate robust joint transmitter and receiver power allocation where the channel state information (CSI) is not perfect. The CSI error is assumed to be unknown but bounded by a deterministic value. This problem is formulated as a semidefinite programming (SDP) problem with bilinear matrix inequality (BMI) constraints. Numerical results show that, with imperfect CSI, the minimax MSE criterion also outperforms the minimum total MSE criterion in terms of the maximum and average BERs.

  14. 36 CFR 1192.83 - Mobility aid accessibility.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... areas, each with a minimum clear floor space of 48 inches by 30 inches, which do not unduly restrict passenger flow. Space to accommodate wheelchairs and mobility aids may be provided within the normal area used by standees and designation of specific spaces is not required. (2) Exception. If lifts, ramps or...

  15. 36 CFR 1192.83 - Mobility aid accessibility.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... areas, each with a minimum clear floor space of 48 inches by 30 inches, which do not unduly restrict passenger flow. Space to accommodate wheelchairs and mobility aids may be provided within the normal area used by standees and designation of specific spaces is not required. (2) Exception. If lifts, ramps or...

  16. Mobile learning to improve mathematics teachers mathematical competencies

    NASA Astrophysics Data System (ADS)

    Hendrayana, A.; Wahyudin

    2018-01-01

    The role of teachers is crucial to the success of mathematics learning. One of the learning indicator is characterized by the students’ improved mathematical proficiency. In order to increase that, it is necessary to improve the teacher’s mathematical skills first. For that, it needs an innovative way to get teachers close to easily accessible learning resources through technology. The technology can facilitate teachers to access learning resources anytime and anywhere. The appropriate information technology is mobile learning. Innovations that can make teachers easy to access learning resources are mobile applications that can be accessed anytime and anywhere either online or offline. The research method was research development method. In preliminary analysis, subjects consist of teachers and lecturers in professional teacher education program. The results that the teachers ready to adopt mobile-learning for the improvement of their skills.

  17. Spectral shaping of spreading sequences as a mean to address the trade-off between narrowband and multi-access interferences in UWB systems

    NASA Astrophysics Data System (ADS)

    Mangia, Mauro; Pareschi, Fabio; Rovatti, Riccardo; Setti, Gianluca

    This paper presents a way to cope with the need of simultaneously rejecting narrowband interference and multi-access interference in a UWB system based on direct-sequence CDMA. With this aim in mind, we rely on a closed-form expression of the system bit error probability in presence of both effects. By means of such a formula, we evaluate the effect of spectrum shaping techniques applied to the spreading sequences. The availability of a certain number of degrees of freedom in deciding the spectral profile allows us to cope with different configurations depending on the relative interfering power but also on the relative position of the signal center frequency and the narrowband interferer.

  18. 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.

  19. 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. © The Author 2015. Published by Oxford University Press on behalf of the American Medical Informatics Association. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  20. Multi-static networked 3D ladar for surveillance and access control

    NASA Astrophysics Data System (ADS)

    Wang, Y.; Ogirala, S. S. R.; Hu, B.; Le, Han Q.

    2007-04-01

    A theoretical design and simulation of a 3D ladar system concept for surveillance, intrusion detection, and access control is described. It is a non-conventional system architecture that consists of: i) multi-static configuration with an arbitrarily scalable number of transmitters (Tx's) and receivers (Rx's) that form an optical wireless code-division-multiple-access (CDMA) network, and ii) flexible system architecture with modular plug-and-play components that can be deployed for any facility with arbitrary topology. Affordability is a driving consideration; and a key feature for low cost is an asymmetric use of many inexpensive Rx's in conjunction with fewer Tx's, which are generally more expensive. The Rx's are spatially distributed close to the surveyed area for large coverage, and capable of receiving signals from multiple Tx's with moderate laser power. The system produces sensing information that scales as NxM, where N, M are the number of Tx's and Rx's, as opposed to linear scaling ~N in non-network system. Also, for target positioning, besides laser pointing direction and time-of-flight, the algorithm includes multiple point-of-view image fusion and triangulation for enhanced accuracy, which is not applicable to non-networked monostatic ladars. Simulation and scaled model experiments on some aspects of this concept are discussed.

  1. 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.

  2. Single-port access laparoscopic reversal of Hartmann operation.

    PubMed

    Borowski, D W; Kanakala, V; Agarwal, A K; Tabaqchali, M A; Garg, D K; Gill, T S

    2011-08-01

    Single-port access offers cosmetic advantages in addition to the well-recognized benefits of standard multiport laparoscopic surgery, and can be performed with the use of standard straight instruments. We describe a technique of single-port access reversal of Hartmann colostomy by use of the colostomy site for access. After routine skin preparation and laparoscopic setup, the colostomy is mobilized from its mucocutaneous border, and the anvil of a circular stapler is secured to the distal lumen. By the use of a GelPoint system with 3 or 4 trocars, the intra-abdominal adhesions are divided and the splenic flexure is mobilized to achieve sufficient access to the abdominal and pelvic cavities and proximal colonic mobility. The rectal stump is mobilized to the mid rectum, starting from the posterior mesorectal fascia around to the anterior rectal wall. A tension-free colorectal anastomosis is secured with a standard circular stapling device inserted transanally, and leak tested. The colostomy wound is closed in standard fashion. Five patients underwent single-port access reversal of Hartmann resection (4 diverticular perforations and 1 pT3N0 colon cancer), with a mean operating time of 155 (range, 137-187) minutes and a median length of stay of 3 (range, 2-11) days. There were no conversions, major surgical morbidity, or deaths. Single-port access reversal of Hartmann colostomy through the stoma site is safe, and it offers additional cosmetic advantages with no apparent additional morbidity in comparison with standard multiport surgery.

  3. Simulated Assessment of Interference Effects in Direct Sequence Spread Spectrum (DSSS) QPSK Receiver

    DTIC Science & Technology

    2014-03-27

    bit error rate BPSK binary phase shift keying CDMA code division multiple access CSI comb spectrum interference CW continuous wave DPSK differential... CDMA ) and GPS systems which is a Gold code. This code is generated by a modulo-2 operation between two different preferred m-sequences. The preferred m...10 SNR Sim (dB) S N R O ut ( dB ) SNR RF SNR DS Figure 3.26: Comparison of input S NRS im and S NROut of the band-pass RF filter (S NRRF) and

  4. 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

  5. Use of mobile devices to answer online surveys: implications for research.

    PubMed

    Cunningham, John A; Neighbors, Clayton; Bertholet, Nicolas; Hendershot, Christian S

    2013-07-08

    There is a growing use of mobile devices to access the Internet. We examined whether participants who used a mobile device to access a brief online survey were quicker to respond to the survey but also, less likely to complete it than participants using a traditional web browser. Using data from a recently completed online intervention trial, we found that participants using mobile devices were quicker to access the survey but less likely to complete it compared to participants using a traditional web browser. More concerning, mobile device users were also less likely to respond to a request to complete a six week follow-up survey compared to those using traditional web browsers. With roughly a third of participants using mobile devices to answer an online survey in this study, the impact of mobile device usage on survey completion rates is a concern. ClinicalTrials.gov: NCT01521078.

  6. 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…

  7. Understanding the mobile internet to develop the next generation of online medical teaching tools

    PubMed Central

    Christiano, Cynthia; Ferris, Maria

    2011-01-01

    Healthcare providers (HCPs) use online medical information for self-directed learning and patient care. Recently, the mobile internet has emerged as a new platform for accessing medical information as it allows mobile devices to access online information in a manner compatible with their restricted storage. We investigated mobile internet usage parameters to direct the future development of mobile internet teaching websites. Nephrology On-Demand Mobile (NODM) (http://www.nephrologyondemand.org) was made accessible to all mobile devices. From February 1 to December 31, 2010, HCP use of NODM was tracked using code inserted into the root files. Nephrology On-Demand received 15 258 visits, of which approximately 10% were made to NODM, with the majority coming from the USA. Most access to NODM was through the Apple iOS family of devices and cellular connections were the most frequently used. These findings provide a basis for the future development of mobile nephrology and medical teaching tools. PMID:21659443

  8. Understanding the mobile internet to develop the next generation of online medical teaching tools.

    PubMed

    Desai, Tejas; Christiano, Cynthia; Ferris, Maria

    2011-01-01

    Healthcare providers (HCPs) use online medical information for self-directed learning and patient care. Recently, the mobile internet has emerged as a new platform for accessing medical information as it allows mobile devices to access online information in a manner compatible with their restricted storage. We investigated mobile internet usage parameters to direct the future development of mobile internet teaching websites. Nephrology On-Demand Mobile (NOD(M)) (http://www.nephrologyondemand.org) was made accessible to all mobile devices. From February 1 to December 31, 2010, HCP use of NOD(M) was tracked using code inserted into the root files. Nephrology On-Demand received 15,258 visits, of which approximately 10% were made to NOD(M), with the majority coming from the USA. Most access to NOD(M) was through the Apple iOS family of devices and cellular connections were the most frequently used. These findings provide a basis for the future development of mobile nephrology and medical teaching tools.

  9. Using mobile phone technology to provide recovery support for women offenders.

    PubMed

    Scott, Christy K; Johnson, Kimberly; Dennis, Michael L

    2013-10-01

    Mobile technology holds promise as a recovery tool for people with substance use disorders. However, some populations who may benefit the most may not have access to or experience with mobile phones. Incarcerated women represent a group at high risk for recidivism and relapse to substance abuse. Cost-effective mechanisms must be in place to support their recovery upon release. This study explores using mobile technology as a recovery management tool for women offenders residing in the community following release from jail. This study surveyed 325 minority women offenders with substance use disorders to determine whether or not they use cell phones, their comfort with texting and search features, and the social networks that they access from mobile phones. We found that 83% of survey subjects had cell phones; 30% of those were smartphones. Seventy-seven percent of the women reported access to supportive friends, and 88% had close family members they contacted regularly using mobile technology. Results indicated that most of the women were comfortable using a mobile phone, although the majority of them had prepaid minutes rather than plans, and most did currently use smartphones or have the capability to download applications or access social networks via their phones. Most women reported that they would be comfortable using a mobile phone to text, e-mail, and answer surveys. The high rate of adoption of mobile technology by women offenders makes them a promising target for recovery support delivered via mobile phone.

  10. Transformations: Mobile Interaction & Language Learning

    ERIC Educational Resources Information Center

    Carroll, Fiona; Kop, Rita; Thomas, Nathan; Dunning, Rebecca

    2015-01-01

    Mobile devices and the interactions that these technologies afford have the potential to change the face and nature of education in our schools. Indeed, mobile technological advances are seen to offer better access to educational material and new interactive ways to learn. However, the question arises, as to whether these new technologies are…

  11. ML Crew Access Arm Move

    NASA Image and Video Library

    2017-11-10

    The Orion crew access arm is secured on a flatbed transporter for its move from a storage location at NASA's Kennedy Space Center in Florida to the mobile launcher (ML) tower near the Vehicle Assembly Building at the center. The crew access arm will be installed at about the 274-foot level on the mobile launcher tower. It will rotate from its retracted position and interface with the Orion crew hatch location to provide entry to the Orion crew module. The Ground Systems Development and Operations Program is overseeing installation of umbilicals and launch accessories on the ML tower to prepare for Exploration Mission-1.

  12. 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.

  13. 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.

  14. 33 CFR 334.782 - SUPSHIP Bath Maine Detachment Mobile at AUSTAL, USA, Mobile, AL; restricted area.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... warranted access into the restricted navigation area be needed, all entities are to contact the Supervisor... Mobile at AUSTAL, USA, Mobile, AL; restricted area. 334.782 Section 334.782 Navigation and Navigable Waters CORPS OF ENGINEERS, DEPARTMENT OF THE ARMY, DEPARTMENT OF DEFENSE DANGER ZONE AND RESTRICTED AREA...

  15. 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…

  16. Quantum key distribution in multicore fibre for secure radio access networks

    NASA Astrophysics Data System (ADS)

    Llorente, Roberto; Provot, Antoine; Morant, Maria

    2018-01-01

    Broadband access in optical domain usually focuses in providing a pervasive cost-effective high bitrate communication in a given area. Nowadays, it is of utmost interest also to be able to provide a secure communication to the costumers in the area. Wireless access networks rely on optical domain for both fronthaul and backhaul of the radio access network (C-RAN). Multicore fiber (MCF) has been proposed as a promising candidate for the optical media of choice in nextgeneration wireless. The capacity demand of next-generation 5G networks makes interesting the use of high-capacity optical solutions as space-division multiplexing of different signals over MCF media. This work addresses secure MCF communication supporting C-RAN architectures. The paper proposes the use of one core in the MCF to transport securely an optical quantum key encoding altogether with end-to-end wireless signal transmitted in the remaining cores in radio-over-fiber (RoF). The RoF wireless signals are suitable for radio access fronthaul and backhaul. The theoretical principle and simulation analysis of quantum key distribution (QKD) are presented in this paper. The potential impact of optical RoF transmission crosstalk impairments is assessed experimentally considering different cellular signals on the remaining optical cores in the MCF. The experimental results report fronthaul performance over a four-core optical fiber with RoF transmission of full-standard CDMA signals providing 3.5G services in one core, HSPA+ signals providing 3.9G services in the second core and 3GPP LTEAdvanced signals providing 4G services in the third core, considering that the QKD signal is allocated in the fourth core.

  17. Accessibility to health care facilities in Montreal Island: an application of relative accessibility indicators from the perspective of senior and non-senior residents.

    PubMed

    Paez, Antonio; Mercado, Ruben G; Farber, Steven; Morency, Catherine; Roorda, Matthew

    2010-10-25

    Geographical access to health care facilities is known to influence health services usage. As societies age, accessibility to health care becomes an increasingly acute public health concern. It is known that seniors tend to have lower mobility levels, and it is possible that this may negatively affect their ability to reach facilities and services. Therefore, it becomes important to examine the mobility situation of seniors vis-a-vis the spatial distribution of health care facilities, to identify areas where accessibility is low and interventions may be required. Accessibility is implemented using a cumulative opportunities measure. Instead of assuming a fixed bandwidth (i.e. a distance threshold) for measuring accessibility, in this paper the bandwidth is defined using model-based estimates of average trip length. Average trip length is an all-purpose indicator of individual mobility and geographical reach. Adoption of a spatial modelling approach allows us to tailor these estimates of travel behaviour to specific locations and person profiles. Replacing a fixed bandwidth with these estimates permits us to calculate customized location- and person-based accessibility measures that allow inter-personal as well as geographical comparisons. The case study is Montreal Island. Geo-coded travel behaviour data, specifically average trip length, and relevant traveller's attributes are obtained from the Montreal Household Travel Survey. These data are complemented with information from the Census. Health care facilities, also geo-coded, are extracted from a comprehensive business point database. Health care facilities are selected based on Standard Industrial Classification codes 8011-21 (Medical Doctors and Dentists). Model-based estimates of average trip length show that travel behaviour varies widely across space. With the exception of seniors in the downtown area, older residents of Montreal Island tend to be significantly less mobile than people of other age cohorts

  18. Inter-Domain Roaming Mechanism Transparent to Mobile Nodes among PMIPv6 Networks

    NASA Astrophysics Data System (ADS)

    Park, Soochang; Lee, Euisin; Jin, Min-Sook; Kim, Sang-Ha

    In Proxy Mobile IPv6 (PMIPv6), when a Mobile Node (MN) enters a PMIPv6 domain and attaches to an access link, the router on the access link detects attachment of the MN by the link-layer access. All elements of PMIPv6 including the router then provide network-based mobility management service for the MN. If the MN moves to another router in this PMIPv6 domain, the new router emulates attachment to the previous router by providing same network prefix to the MN. In other words, PMIPv6 provides rapid mobility management based on layer-2 attachment and transparent mobility support to the MN by emulating layer-3 attachment with respect to intra-domain roaming. However, when the MN moves to other PMIPv6 domains, although the domains also provide the network-based mobility management service, the MN should exploit the host-based mobility management protocol, i.e. Mobile IPv6 (MIPv6), for the inter-domain roaming. Hence, this letter proposes the rapid and transparent inter-domain roaming mechanism controlled by the networks adopting PMIPv6.

  19. 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…

  20. Clandestine Transmissions and Operations of Embedded Software on Cellular Mobile Devices

    DTIC Science & Technology

    2011-09-01

    Register EMS Enhanced Message Service FDMA Frequency Division Multiple Access GMT Greenwich Mean Time GMSC Gateway Mobile Switching Center...Message Switching Center SMS-IWMSC SMS-Interworking Mobile-Service Switching Center TCH Traffic Channels TDMA Time Division Multiple Access TP...assume the user will not attempt to re-program the device. Finally, we assume that the owner and user do not have root access and cannot disable any

  1. Availability and acceptability of HIV counselling and testing services. A qualitative study comparing clients' experiences of accessing HIV testing at public sector primary health care facilities or non-governmental mobile services in Cape Town, South Africa.

    PubMed

    Meehan, Sue-Ann; Leon, Natalie; Naidoo, Pren; Jennings, Karen; Burger, Ronelle; Beyers, Nulda

    2015-09-02

    The South African government is striving for universal access to HIV counselling and testing (HCT), a fundamental component of HIV care and prevention. In the Cape Town district, Western Cape Province of South Africa, HCT is provided free of charge at publically funded primary health care (PHC) facilities and through non-governmental organizations (NGOs). This study investigated the availability and accessibility of HCT services; comparing health seeking behaviour and client experiences of HCT across public PHC facilities (fixed sites) and NGO mobile services. This qualitative study used semi-structured interviews. Systematic sampling was used to select 16 participants who accessed HCT in either a PHC facility (8) or a NGO mobile service (8). Interviews, conducted between March and June 2011, were digitally recorded, transcribed and where required, translated into English. Constant comparative and thematic analysis was used to identify common and divergent responses and themes in relation to the key questions (reasons for testing, choice of service provider and experience of HCT). The sample consisted of 12 females and 4 males with an age range of 19-60 years (median age 28 years). Motivations for accessing health facilities and NGO services were similar; opportunity to test, being affected by HIV and a perceived personal risk for contracting HIV. Participants chose a particular service provider based on accessibility, familiarity with and acceptability of that service. Experiences of both services were largely positive, though instances of poor staff attitude and long waiting times were reported at PHC facilities. Those attending NGO services reported shorter waiting times and overall positive testing experiences. Concerns about lack of adequate privacy and associated stigma were expressed about both services. Realised access to HCT is dependent on availability and acceptability of HCT services. Those who utilised either a NGO mobile service or a public PHC

  2. Operational evaluation of a DGPS / SATCOM VTS : final report

    DOT National Transportation Integrated Search

    1996-09-01

    Satellite communications (SATCOM) using code division multiple access(CDMA) modulation and burst messaging, provided a new dimension to communication channel capacity, operating dependability, and area of coverage. This technology, together with diff...

  3. Secure Location Provenance for Mobile Devices

    DTIC Science & Technology

    2015-07-01

    SECURE LOCATION PROVENANCE FOR MOBILE DEVICES UNIVERSITY OF ALABAMA AT BIRMINGHAM JULY 2015 FINAL TECHNICAL REPORT...PROVENANCE FOR MOBILE DEVICES 5a. CONTRACT NUMBER FA8750-12-2-0254 5b. GRANT NUMBER N/A 5c. PROGRAM ELEMENT NUMBER 69220K 6. AUTHOR(S) Ragib Hasan...based services allow mobile device users to access various services based on the users’ current physical location information. Path-critical applications

  4. Higher Education Students’ Behaviour to Adopt Mobile Learning

    NASA Astrophysics Data System (ADS)

    Batmetan, J. R.; Palilingan, V. R.

    2018-02-01

    Mobile phone is an electronic device most often used by Y generation in Indonesia. This ages have become an important part in the growth of higher education in this country. The problem raised in this study is that very few students in higher education are adopting and accessing digital learning content using mobile phones. The objective of this study is to investigate the higher education students’ behaviour in using mobile learning. The research method used is Structural equation models (SEM) method to analyse the factors that influence higher education students’ behaviour in using mobile learning. The results of this study indicate tends of this student 85% to keep internet access in privacy. The majority of respondent is 78% having behaviour to keep adopting mobile learning and still use it in the future. Why? because this study shows that on the level of usability, easy to use, easy to learn, in various devices have a significant effect on the level of adoption of mobile learning. Implication of this study is higher education students’ behaviour of especially Y generation tends to prioritize the usability towards mobile learning and will continue to adopt mobile learning in the future.

  5. 7 CFR 1755.509 - Mobile homes.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 7 Agriculture 11 2014-01-01 2014-01-01 false Mobile homes. 1755.509 Section 1755.509 Agriculture... homes. (a) Customer access location installations at mobile homes shall be treated the same whether the homes are mounted on permanent foundations or temporary foundations and shall be installed as specified...

  6. 7 CFR 1755.509 - Mobile homes.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 7 Agriculture 11 2012-01-01 2012-01-01 false Mobile homes. 1755.509 Section 1755.509 Agriculture... homes. (a) Customer access location installations at mobile homes shall be treated the same whether the homes are mounted on permanent foundations or temporary foundations and shall be installed as specified...

  7. 7 CFR 1755.509 - Mobile homes.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 7 Agriculture 11 2013-01-01 2013-01-01 false Mobile homes. 1755.509 Section 1755.509 Agriculture... homes. (a) Customer access location installations at mobile homes shall be treated the same whether the homes are mounted on permanent foundations or temporary foundations and shall be installed as specified...

  8. 7 CFR 1755.509 - Mobile homes.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 7 Agriculture 11 2011-01-01 2011-01-01 false Mobile homes. 1755.509 Section 1755.509 Agriculture... homes. (a) Customer access location installations at mobile homes shall be treated the same whether the homes are mounted on permanent foundations or temporary foundations and shall be installed as specified...

  9. 7 CFR 1755.509 - Mobile homes.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 7 Agriculture 11 2010-01-01 2010-01-01 false Mobile homes. 1755.509 Section 1755.509 Agriculture... homes. (a) Customer access location installations at mobile homes shall be treated the same whether the homes are mounted on permanent foundations or temporary foundations and shall be installed as specified...

  10. Mobile work: Ergonomics in a rapidly changing work environment.

    PubMed

    Honan, Meg

    2015-01-01

    Places of work have been completely transformed by innovations in mobile work tools and ever-present access to internet data. This article characterizes use patterns and provides preliminary considerations for productive and comfortable use of common mobile devices. Two surveys described trends in mobile work. In the first, ergonomics professionals who oversee programs reported common mobile devices, their users and what data is accessed. The second, an end user survey, explored common activities performed on mobile devices, duration of use and locations where mobile work is common. The survey results provide a baseline data point for the status of mobile work in early 2014. Research indicates that additional risks have been introduced to the neck, thumbs and hands when using mobile devices. Possible trends regarding device use and work locations emerge. Intervention studies provide some direction for the practitioner. Practical strategies are outlined to reduce exposure intensity and duration. Contemporary mobile work presents tremendous change and opportunity for ergonomists and researchers to keep pace with fitting the changing models of work to the person. Continued research is needed on current mobile device use patterns to better understand ergonomic risk exposure in this rapidly changing realm.

  11. 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.

  12. Nuclear Hell On Wheels Examining The Need For A Mobile ICBM

    DTIC Science & Technology

    2015-02-17

    www.defenseone.com/ideas/2014/11/last-thing- us-needs-are-mobile-nuclear-missiles/98828/?oref=d- skybox (accessed 28 Nov 2014) 4 Department of Defense...last-thing-us-needs- are-mobile-nuclear-missiles/98828/?oref=d- skybox (accessed 28 Nov 2014) Craig, Campbell. Destroying the Village: Eisenhower and

  13. GalileoMobile: Interactive astronomy activities in schools

    NASA Astrophysics Data System (ADS)

    Vasquez, M.; Dasi Espuig, M.

    2014-04-01

    GalileoMobile is an itinerant science education initiative run on a voluntary basis by an international team of astronomers, educators, and science communicators. Our team's main goal is to make astronomy accessible to schools and communities around the globe that have little or no access to outreach actions. We do this by performing teacher workshops, activities with students, and donating educational material. Since the creation of GalileoMobile in 2008, we have travelled to Chile, Bolivia, Peru, India, and Uganda, and worked with 56 schools in total.

  14. Missed Opportunity? Leveraging Mobile Technology to Reduce Racial Health Disparities.

    PubMed

    Ray, Rashawn; Sewell, Abigail A; Gilbert, Keon L; Roberts, Jennifer D

    2017-10-01

    Blacks and Latinos are less likely than whites to access health insurance and utilize health care. One way to overcome some of these racial barriers to health equity may be through advances in technology that allow people to access and utilize health care in innovative ways. Yet, little research has focused on whether the racial gap that exists for health care utilization also exists for accessing health information online and through mobile technologies. Using data from the Health Information National Trends Survey (HINTS), we examine racial differences in obtaining health information online via mobile devices. We find that blacks and Latinos are more likely to trust online newspapers to get health information than whites. Minorities who have access to a mobile device are more likely to rely on the Internet for health information in a time of strong need. Federally insured individuals who are connected to mobile devices have the highest probability of reliance on the Internet as a go-to source of health information. We conclude by discussing the importance of mobile technologies for health policy, particularly related to developing health literacy, improving health outcomes, and contributing to reducing health disparities by race and health insurance status. Copyright © 2017 by Duke University Press.

  15. 36 CFR § 1192.83 - Mobility aid accessibility.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... users to reach areas, each with a minimum clear floor space of 48 inches by 30 inches, which do not unduly restrict passenger flow. Space to accommodate wheelchairs and mobility aids may be provided within the normal area used by standees and designation of specific spaces is not required. (2) Exception. If...

  16. Providing Epistemic Support For Assessments Through Mobile-Supported Sharing Activities1

    PubMed Central

    Raclaw, Joshua; Robles, Jessica S.; DiDomenico, Stephen M.

    2017-01-01

    This paper examines how participants in face-to-face conversation employ mobile phones as a resource for social action. We focus on what we call mobile-supported sharing activities, in which participants use a mobile phone to share text or images with others by voicing text aloud from their mobile or providing others with visual access to the device’s display screen. Drawing from naturalistic video recordings, we focus on how mobile-supported sharing activities invite assessments by providing access to an object that is not locally accessible to the participants. Such practices make relevant co-participants’ assessment of these objects and allow for different forms of co-participation across sequence types. We additionally examine how the organization of assessments during these sharing activities displays sensitivity to preference structure. The analysis illustrates the relevance of embodiment, local objects, and new communicative technologies to the production of action in co-present interaction. Data are in American English. PMID:28936031

  17. 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.

  18. 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…

  19. Multimedia information processing in the SWAN mobile networked computing system

    NASA Astrophysics Data System (ADS)

    Agrawal, Prathima; Hyden, Eoin; Krzyzanowsji, Paul; Srivastava, Mani B.; Trotter, John

    1996-03-01

    Anytime anywhere wireless access to databases, such as medical and inventory records, can simplify workflow management in a business, and reduce or even eliminate the cost of moving paper documents. Moreover, continual progress in wireless access technology promises to provide per-user bandwidths of the order of a few Mbps, at least in indoor environments. When combined with the emerging high-speed integrated service wired networks, it enables ubiquitous and tetherless access to and processing of multimedia information by mobile users. To leverage on this synergy an indoor wireless network based on room-sized cells and multimedia mobile end-points is being developed at AT&T Bell Laboratories. This research network, called SWAN (Seamless Wireless ATM Networking), allows users carrying multimedia end-points such as PDAs, laptops, and portable multimedia terminals, to seamlessly roam while accessing multimedia data streams from the wired backbone network. A distinguishing feature of the SWAN network is its use of end-to-end ATM connectivity as opposed to the connectionless mobile-IP connectivity used by present day wireless data LANs. This choice allows the wireless resource in a cell to be intelligently allocated amongst various ATM virtual circuits according to their quality of service requirements. But an efficient implementation of ATM in a wireless environment requires a proper mobile network architecture. In particular, the wireless link and medium-access layers need to be cognizant of the ATM traffic, while the ATM layers need to be cognizant of the mobility enabled by the wireless layers. This paper presents an overview of SWAN's network architecture, briefly discusses the issues in making ATM mobile and wireless, and describes initial multimedia applications for SWAN.

  20. Mobile Code: The Future of the Internet

    DTIC Science & Technology

    1999-01-01

    code ( mobile agents) to multiple proxies or servers " Customization " (e.g., re-formatting, filtering, metasearch) Information overload Diversified... Mobile code is necessary, rather than client-side code, since many customization features (such as information monitoring) do not work if the...economic foundation for Web sites, many Web sites earn money solely from advertisements . If these sites allow mobile agents to easily access the content

  1. 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…

  2. 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.

  3. 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.

  4. Mobile money, smallholder farmers, and household welfare in Kenya.

    PubMed

    Kikulwe, Enoch M; Fischer, Elisabeth; Qaim, Matin

    2014-01-01

    The use of mobile phones has increased rapidly in many developing countries, including in rural areas. Besides reducing the costs of communication and improving access to information, mobile phones are an enabling technology for other innovations. One important example are mobile phone based money transfers, which could be very relevant for the rural poor, who are often underserved by the formal banking system. We analyze impacts of mobile money technology on the welfare of smallholder farm households in Kenya. Using panel survey data and regression models we show that mobile money use has a positive impact on household income. One important pathway is through remittances received from relatives and friends. Such remittances contribute to income directly, but they also help to reduce risk and liquidity constraints, thus promoting agricultural commercialization. Mobile money users apply more purchased farm inputs, market a larger proportion of their output, and have higher profits than non-users of this technology. These results suggest that mobile money can help to overcome some of the important smallholder market access constraints that obstruct rural development and poverty reduction.

  5. Mobile Money, Smallholder Farmers, and Household Welfare in Kenya

    PubMed Central

    Kikulwe, Enoch M.; Fischer, Elisabeth; Qaim, Matin

    2014-01-01

    The use of mobile phones has increased rapidly in many developing countries, including in rural areas. Besides reducing the costs of communication and improving access to information, mobile phones are an enabling technology for other innovations. One important example are mobile phone based money transfers, which could be very relevant for the rural poor, who are often underserved by the formal banking system. We analyze impacts of mobile money technology on the welfare of smallholder farm households in Kenya. Using panel survey data and regression models we show that mobile money use has a positive impact on household income. One important pathway is through remittances received from relatives and friends. Such remittances contribute to income directly, but they also help to reduce risk and liquidity constraints, thus promoting agricultural commercialization. Mobile money users apply more purchased farm inputs, market a larger proportion of their output, and have higher profits than non-users of this technology. These results suggest that mobile money can help to overcome some of the important smallholder market access constraints that obstruct rural development and poverty reduction. PMID:25286032

  6. 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…

  7. Early Experiences with Mobile Electronic Health Records Application in a Tertiary Hospital in Korea

    PubMed Central

    Park, Minah; Hong, Eunseok; Kim, Sunhyu; Ahn, Ryeok; Hong, Jungseok; Song, Seungyeol; Kim, Tak; Kim, Jeongkeun; Yeo, Seongwoon

    2015-01-01

    Objectives Recent advances in mobile technology have opened up possibilities to provide strongly integrated mobile-based services in healthcare and telemedicine. Although the number of mobile Electronic Health Record (EHR) applications is large and growing, there is a paucity of evidence demonstrating the usage patterns of these mobile applications by healthcare providers. This study aimed to illustrate the deployment process for an integrated mobile EHR application and to analyze usage patterns after provision of the mobile EHR service. Methods We developed an integrated mobile application that aimed to enhance the mobility of healthcare providers by improving access to patient- and hospital-related information during their daily medical activities. The study included mobile EHR users who accessed patient healthcare records between May 2013 and May 2014. We performed a data analysis using a web server log file analyzer from the integrated EHR system. Cluster analysis was applied to longitudinal user data based on their application usage pattern. Results The mobile EHR service named M-UMIS has been in service since May 2013. Every healthcare provider in the hospital could access the mobile EHR service and view the medical charts of their patients. The frequency of using services and network packet transmission on the M-UMIS increased gradually during the study period. The most frequently accessed service in the menu was the patient list. Conclusions A better understanding regarding the adoption of mobile EHR applications by healthcare providers in patient-centered care provides useful information to guide the design and implementation of future applications. PMID:26618036

  8. Dicoogle Mobile: a medical imaging platform for Android.

    PubMed

    Viana-Ferreira, Carlos; Ferreira, Daniel; Valente, Frederico; Monteiro, Eriksson; Costa, Carlos; Oliveira, José Luís

    2012-01-01

    Mobile computing technologies are increasingly becoming a valuable asset in healthcare information systems. The adoption of these technologies helps to assist in improving quality of care, increasing productivity and facilitating clinical decision support. They provide practitioners with ubiquitous access to patient records, being actually an important component in telemedicine and tele-work environments. We have developed Dicoogle Mobile, an Android application that provides remote access to distributed medical imaging data through a cloud relay service. Besides, this application has the capability to store and index local imaging data, so that they can also be searched and visualized. In this paper, we will describe Dicoogle Mobile concept as well the architecture of the whole system that makes it running.

  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. MobileASL: intelligibility of sign language video over mobile phones.

    PubMed

    Cavender, Anna; Vanam, Rahul; Barney, Dane K; Ladner, Richard E; Riskin, Eve A

    2008-01-01

    For Deaf people, access to the mobile telephone network in the United States is currently limited to text messaging, forcing communication in English as opposed to American Sign Language (ASL), the preferred language. Because ASL is a visual language, mobile video phones have the potential to give Deaf people access to real-time mobile communication in their preferred language. However, even today's best video compression techniques can not yield intelligible ASL at limited cell phone network bandwidths. Motivated by this constraint, we conducted one focus group and two user studies with members of the Deaf Community to determine the intelligibility effects of video compression techniques that exploit the visual nature of sign language. Inspired by eye tracking results that show high resolution foveal vision is maintained around the face, we studied region-of-interest encodings (where the face is encoded at higher quality) as well as reduced frame rates (where fewer, better quality, frames are displayed every second). At all bit rates studied here, participants preferred moderate quality increases in the face region, sacrificing quality in other regions. They also preferred slightly lower frame rates because they yield better quality frames for a fixed bit rate. The limited processing power of cell phones is a serious concern because a real-time video encoder and decoder will be needed. Choosing less complex settings for the encoder can reduce encoding time, but will affect video quality. We studied the intelligibility effects of this tradeoff and found that we can significantly speed up encoding time without severely affecting intelligibility. These results show promise for real-time access to the current low-bandwidth cell phone network through sign-language-specific encoding techniques.

  11. 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…

  12. Effects of Practice Type in the Here and Now Mobile Learning Environment

    ERIC Educational Resources Information Center

    Tutty, Jeremy I.; Martin, Florence

    2014-01-01

    This generation of technology is characterized by mobile and portable devices such as smartphones and tablet computers with wireless broadband access. Mobile technologies enable a new kind of learning called "here and now learning," where learners have access to information anytime and anywhere to perform authentic activities in the…

  13. Simple video format for mobile applications

    NASA Astrophysics Data System (ADS)

    Smith, John R.; Miao, Zhourong; Li, Chung-Sheng

    2000-04-01

    With the advent of pervasive computing, there is a growing demand for enabling multimedia applications on mobile devices. Large numbers of pervasive computing devices, such as personal digital assistants (PDAs), hand-held computer (HHC), smart phones, portable audio players, automotive computing devices, and wearable computers are gaining access to online information sources. However, the pervasive computing devices are often constrained along a number of dimensions, such as processing power, local storage, display size and depth, connectivity, and communication bandwidth, which makes it difficult to access rich image and video content. In this paper, we report on our initial efforts in designing a simple scalable video format with low-decoding and transcoding complexity for pervasive computing. The goal is to enable image and video access for mobile applications such as electronic catalog shopping, video conferencing, remote surveillance and video mail using pervasive computing devices.

  14. Research of Ad Hoc Networks Access Algorithm

    NASA Astrophysics Data System (ADS)

    Xiang, Ma

    With the continuous development of mobile communication technology, Ad Hoc access network has become a hot research, Ad Hoc access network nodes can be used to expand capacity of multi-hop communication range of mobile communication system, even business adjacent to the community, improve edge data rates. When the ad hoc network is the access network of the internet, the gateway discovery protocol is very important to choose the most appropriate gateway to guarantee the connectivity between ad hoc network and IP based fixed networks. The paper proposes a QoS gateway discovery protocol which uses the time delay and stable route to the gateway selection conditions. And according to the gateway discovery protocol, it also proposes a fast handover scheme which can decrease the handover time and improve the handover efficiency.

  15. Mobile devices in medicine: a survey of how medical students, residents, and faculty use smartphones and other mobile devices to find information.

    PubMed

    Boruff, Jill T; Storie, Dale

    2014-01-01

    The research investigated the extent to which students, residents, and faculty members in Canadian medical faculties use mobile devices, such as smartphones (e.g., iPhone, Android, Blackberry) and tablet computers (e.g., iPad), to answer clinical questions and find medical information. The results of this study will inform how health libraries can effectively support mobile technology and collections. An electronic survey was distributed by medical librarians at four Canadian universities to medical students, residents, and faculty members via departmental email discussion lists, personal contacts, and relevant websites. It investigated the types of information sought, facilitators to mobile device use in medical information seeking, barriers to access, support needs, familiarity with institutionally licensed resources, and most frequently used resources. The survey of 1,210 respondents indicated widespread use of smartphones and tablets in clinical settings in 4 Canadian universities. Third- and fourth-year undergraduate students (i.e., those in their clinical clerkships) and medical residents, compared to other graduate students and faculty, used their mobile devices more often, used them for a broader range of activities, and purchased more resources for their devices. Technological and intellectual barriers do not seem to prevent medical trainees and faculty from regularly using mobile devices for their medical information searches; however, barriers to access and lack of awareness might keep them from using reliable, library-licensed resources. Libraries should focus on providing access to a smaller number of highly used mobile resources instead of a huge collection until library-licensed mobile resources have streamlined authentication processes.

  16. Mobile devices in medicine: a survey of how medical students, residents, and faculty use smartphones and other mobile devices to find information*

    PubMed Central

    Boruff, Jill T.; Storie, Dale

    2014-01-01

    Objectives: The research investigated the extent to which students, residents, and faculty members in Canadian medical faculties use mobile devices, such as smartphones (e.g., iPhone, Android, Blackberry) and tablet computers (e.g., iPad), to answer clinical questions and find medical information. The results of this study will inform how health libraries can effectively support mobile technology and collections. Methods: An electronic survey was distributed by medical librarians at four Canadian universities to medical students, residents, and faculty members via departmental email discussion lists, personal contacts, and relevant websites. It investigated the types of information sought, facilitators to mobile device use in medical information seeking, barriers to access, support needs, familiarity with institutionally licensed resources, and most frequently used resources. Results: The survey of 1,210 respondents indicated widespread use of smartphones and tablets in clinical settings in 4 Canadian universities. Third- and fourth-year undergraduate students (i.e., those in their clinical clerkships) and medical residents, compared to other graduate students and faculty, used their mobile devices more often, used them for a broader range of activities, and purchased more resources for their devices. Conclusions: Technological and intellectual barriers do not seem to prevent medical trainees and faculty from regularly using mobile devices for their medical information searches; however, barriers to access and lack of awareness might keep them from using reliable, library-licensed resources. Implications: Libraries should focus on providing access to a smaller number of highly used mobile resources instead of a huge collection until library-licensed mobile resources have streamlined authentication processes. PMID:24415916

  17. Mobile Phone Health Applications for the Federal Sector.

    PubMed

    Burrows, Christin S; Weigel, Fred K

    2016-01-01

    As the US healthcare system moves toward a mobile care model, mobile phones will play a significant role in the future of healthcare delivery. Today, 90% of American adults own a mobile phone and 64% own a smartphone, yet many healthcare organizations are only beginning to explore the opportunities in which mobile phones can improve and streamline care. After searching Google Scholar, the Association for Computing Machinery Database, and PubMed for articles related to mobile phone health applications and cell phone text message health, we selected articles and studies related to the application of mobile phones in healthcare. From our initial review, we identified the potential application areas and continued to refine our search, identifying a total of 55 articles for additional review and analysis. From the literature, we identified 3 main themes for mobile phone implementation in improving healthcare: primary, preventive, and population health. We recommend federal health leaders pursue the value and potential in these areas; not only because 90% of Americans already own mobile phones, but also because mobile phone integration can provide substantial access and potential cost savings. From the positive findings of multiple studies in primary, preventive, and population health, we propose a 5-year federal implementation plan to integrate mobile phone capabilities into federal healthcare delivery. Our proposal has the potential to improve access, reduce costs, and increase patient satisfaction, therefore changing the way the federal sector delivers healthcare by 2021.

  18. Access to Educational Opportunity in Rural Communities: Alternative Patterns of Delivering Vocational Education in Sparsely Populated Areas. Volume 3: The Northwest Multi-District: A Mobile Facilities Center.

    ERIC Educational Resources Information Center

    Peterson, Roland L.; And Others

    Representing the mobile facilities pattern of inter-district cooperation, the Northwest Multi-District case is one of four studies addressing access of rural students to vocational education through inter-school district cooperation. The report identifies essential features of this form of cooperation, details factors facilitating/impeding the…

  19. 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…

  20. 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…

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

    DTIC Science & Technology

    2012-02-28

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

  2. 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.…

  3. Cell Phones, Tablets, and Other Mobile Technology for Users with Visual Impairments

    MedlinePlus

    ... Visual Impairments Cell Phones, Tablets, and Other Mobile Technology for Users with Visual Impairments The Mobile Revolution ... 223 Likes) Cell Phones, Tablets, and Other Mobile Technology Touchscreen Smartphone Accessibility for People with Visual Impairments ...

  4. Teacher perceptions of usefulness of mobile learning devices in rural secondary science classrooms

    NASA Astrophysics Data System (ADS)

    Tighe, Lisa

    The internet and easy accessibility to a wide range of digital content has created the necessity for teachers to embrace and integrate digitial media in their curriculums. Although there is a call for digital media integration in curriculum by current learning standards, rural schools continue to have access to fewer resources due to limited budgets, potentially preventing teachers from having access to the most current technology and science instructional materials. This dissertation identifies the perceptions rural secondary science teachers have on the usefulness of mobile learning devices in the science classroom. The successes and challenges in using mobile learning devices in the secondary classroom were also explored. Throughout this research, teachers generally supported the integration of mobile devices in the classroom, while harboring some concerns relating to student distractability and the time required for integrating mobile devices in exisiting curriculum. Quantitative and qualitative data collected through surveys, interviews, and classroom observations revealed that teachers perceive that mobile devices bring benefits such as ease of communication and easy access to digitial information. However, there are perceived challenges with the ability to effectively communicate complex scientific information via mobile devices, distractibility of students, and the time required to develop effective curriculum to integrate digital media into the secondary science classroom.

  5. 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…

  6. 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

  7. 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

  8. 49 CFR 38.159 - Mobility aid accessibility.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... with the inner barrier (if applicable) down or retracted, gaps between the forward lift platform edge... inches (1220 mm). Such space shall adjoin, and may overlap, an access path. Not more than 6 inches (150 mm) of the required clear floor space may be accommodated for footrests under another seat, modesty...

  9. 49 CFR 38.159 - Mobility aid accessibility.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... with the inner barrier (if applicable) down or retracted, gaps between the forward lift platform edge... inches (1220 mm). Such space shall adjoin, and may overlap, an access path. Not more than 6 inches (150 mm) of the required clear floor space may be accommodated for footrests under another seat, modesty...

  10. 49 CFR 38.23 - Mobility aid accessibility.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... maneuvering into or out of the aisle. The loading-edge barrier (outer barrier) which functions as a loading.... The outer barrier of the lift shall automatically raise or close, or a supplementary system shall... accessible entrance as practicable and shall have a clear floor area of 30 inches by 48 inches. Such space...

  11. 36 CFR 1192.23 - Mobility aid accessibility.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... at vehicle floor height with the inner barrier (if applicable) down or retracted, gaps between the.... Such space shall adjoin, and may overlap, an access path. Not more than 6 inches of the required clear floor space may be accommodated for footrests under another seat provided there is a minimum of 9 inches...

  12. 36 CFR 1192.23 - Mobility aid accessibility.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... at vehicle floor height with the inner barrier (if applicable) down or retracted, gaps between the.... Such space shall adjoin, and may overlap, an access path. Not more than 6 inches of the required clear floor space may be accommodated for footrests under another seat provided there is a minimum of 9 inches...

  13. Wideband, mobile networking technologies

    NASA Astrophysics Data System (ADS)

    Hyer, Kevin L.; Bowen, Douglas G.; Pulsipher, Dennis C.

    2005-05-01

    Ubiquitous communications will be the next era in the evolving communications revolution. From the human perspective, access to information will be instantaneous and provide a revolution in services available to both the consumer and the warfighter. Services will be from the mundane - anytime, anywhere access to any movie ever made - to the vital - reliable and immediate access to the analyzed real-time video from the multi-spectral sensors scanning for snipers in the next block. In the former example, the services rely on a fixed infrastructure of networking devices housed in controlled environments and coupled to fixed terrestrial fiber backbones - in the latter, the services are derived from an agile and highly mobile ad-hoc backbone established in a matter of minutes by size, weight, and power-constrained platforms. This network must mitigate significant changes in the transmission media caused by millisecond-scale atmospheric temperature variations, the deployment of smoke, or the drifting of a cloud. It must mitigate against structural obscurations, jet wash, or incapacitation of a node. To maintain vital connectivity, the mobile backbone must be predictive and self-healing on both near-real-time and real-time time scales. The nodes of this network must be reconfigurable to mitigate intentional and environmental jammers, block attackers, and alleviate interoperability concerns caused by changing standards. The nodes must support multi-access of disparate waveform and protocols.

  14. Use of two test methods to ensure accurate surface firmness and stability measurements for accessibility.

    PubMed

    Axelson, Peter W; Hurley, Seanna L

    2018-05-01

    The firmness and stability of indoor and outdoor surfacing are critical to the accessibility and safety of all environments for people with mobility impairments and/or who use mobility devices. ASTM F1951 laboratory test procedures include pass/fail criteria for determining playground surface accessibility by comparing the work to propel up a 1:14 (7.1%) grade ramp to that of the test surface in a wheelchair. A portable instrumented surface indenter (ISI) was developed to validate that accessibility results obtained in the laboratory are maintained in the field where the surface is installed and used. Accessibility measurements have been made on indoor and outdoor surfaces tested in the laboratory using both the ASTM F1951 and the ISI over 13 years. Correlations between these two methods were calculated. A strong correlation has been demonstrated for the sum of the ISI firmness and stability results compared to the sum of the ASTM F1951 straight propulsion and turning results (R 2 =0.9006). The portable ISI can be used to verify that the firmness and stability of an installed surface in the field correlates to the accessibility results of the surface tested in the laboratory concurrently according to ASTM F1951 and the ISI. Implications for Rehabilitation The Instrumented Surface Indenter (ISI) allows for surfaces in all environments to be tested for firmness and stability, which is critical for wheelchair user safety, especially during rehabilitation when learning to use a wheelchair. The ISI allows for surfaces in all environments to be tested for firmness and stability, which increases access to all indoor and outdoor surfaces, thereby improving the quality of life for people who have mobility impairments and/or use mobility devices, such as canes, crutches, walkers, and wheelchairs. Using the ISI to test the firmness and stability of installed playground surfaces increases access to playgrounds for children with mobility impairments, facilitating

  15. Productivity and quality improvements in health care through airboss mobile messaging services.

    PubMed

    Shah, P J; Martinez, R; Cooney, E

    1997-01-01

    The US health care industry is in the midst of revolutionary changes. Under tremendous pressures from third-party payers and managed care programs to control costs while providing high quality medical services, health care entities are now looking at information technologies to help them achieve their goals. These goals typically include improved productivity, efficiency and decision-making capabilities among staff members. Moreover, hospitals and other health care facilities that provide a broad and integrated range of inpatient and outpatient care, wellness and home care services are in the best position to offer comprehensive packages to managed care and private insurers. Many health care providers and administrators are considered mobile employees. This mobility can range from intra-building and intra-campus to multi-site and metropolitan areas. This group often relies on a variety of information technologies such as personal computers, communicating laptops, pagers, cellular phones, wireline phones, cordless phones and fax machines to stay in touch and handle information needs. These health care professionals require mobile information access and messaging tools to improve communications, control accessibility and enhance decision-making capabilities. AirBoss mobile messaging services could address the health care industry's need for improved messaging capabilities for its mobile employees. The AirBoss family of services supports integrated voice services, data messaging, mobile facsimile and customized information delivery. This paper describes overview of the current mobile data networking capability, the AirBoss architecture, the health care-related applications it addresses and long-term benefits. In addition, a prototype application for mobile home health care workers is illustrated. This prototype application provides integrated e-mail, information services, web access, real-time access and update of patient records from wireline or wireless networks

  16. 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.

  17. 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…

  18. PATI: Patient accessed tailored information: A pilot study to evaluate the effect on preoperative breast cancer patients of information delivered via a mobile application.

    PubMed

    Foley, N M; O'Connell, E P; Lehane, E A; Livingstone, V; Maher, B; Kaimkhani, S; Cil, T; Relihan, N; Bennett, M W; Redmond, H P; Corrigan, M A

    2016-12-01

    The information needs of cancer patients are highly variable. Literature suggests an improved ability to modulate personalised stress, increased patient involvement with decision making, greater satisfaction with treatment choices and reduced anxiety levels in cancer patients who have access to information. The aim of this project was to evaluate the effects of a mobile information application on anxiety levels of patients undergoing surgery for breast cancer. An application was developed for use with Apple iPad containing information on basic breast cancer biology, different treatments used and surgical techniques. Content and face validity studies were performed. A randomized control trial was designed, with a 1:2 allocation. Data collected include basic demographics and type of surgery. Questionnaires used included: the HADS, Mini-MAC, information technology familiarity and information satisfaction. A total of 39 women participated. 13 women had access to an iPad containing additional information and 26 women acted as controls. The mean age was 54 and technology familiarity was similar among both groups. Anxiety and depression scores at seven days were significantly lower in control patients without access to the additional information provided by the mobile application (p = 0.022 and 0.029 respectively). Anxiety and depression in breast cancer patients is both multifactorial and significant, with anxiety levels directly correlating with reduced quality of life. Intuitively, information should improve anxiety levels, however, we have demonstrated that surgical patients with less information reported significantly lower anxiety. We advise the thorough testing and auditing of information initiatives before deployment. Copyright © 2016 Elsevier Ltd. All rights reserved.

  19. It cannot be all about safety: the benefits of prolonged mobility.

    PubMed

    Oxley, Jennifer; Whelan, Michelle

    2008-08-01

    While there is much emphasis on managing the safety of older road users, there is limited understanding and recognition of the significance of mobility and transportation needs, mobility changes in later life, and the impact of reduced mobility on quality of life. Moreover, there is little information about the measures that can be taken to increase or at least maintain mobility in older age. A systematic literature review was undertaken to address the issues associated with the transportation and mobility needs of older road users. Articles and publications were selected for relevance and research strength and strategies and measures aimed to manage the safe mobility of older road users were reviewed. The review provides clear evidence that, for older adults who cease driving, quality of life is reduced and that there are a number of adverse consequences of poor mobility. The misconceptions regarding the risks that older drivers pose on the road and how their safe mobility should be managed are discussed, particularly the implications of current licensing procedures on mobility. Evidence is also presented showing there are subgroups of older adults who are more likely to suffer more pronounced mobility consequences including women and financially disadvantaged groups. Moreover, "best-practice" strategies for maintaining at least some level of mobility for older adults are highlighted in four broad categories: safer road users, safer vehicles, safer roads and infrastructure, and provision of new and innovative alternative transport options that are specifically tailored to older adults. Provision of safe travel options that allow easy access to services and amenities is a vital factor in maintaining mobility amongst older road users. An understanding that continued mobility means access to a private vehicle, either as a driver (for as long as possible as it is safe to drive) or as a passenger, and easy and practical access to other forms of transport is essential

  20. Next Generation Access Network Deployment in Croatia: Optical Access Networks and Current IoT/5G Status

    NASA Astrophysics Data System (ADS)

    Breskovic, Damir; Sikirica, Mladen; Begusic, Dinko

    2018-05-01

    This paper gives an overview and background of optical access network deployment in Croatia. Optical access network development in Croatia has been put into a global as well as in the European Union context. All the challenges and the driving factors for optical access networks deployment are considered. Optical access network architectures that have been deployed by most of the investors in Croatian telecommunication market are presented, as well as the architectures that are in early phase of deployment. Finally, an overview on current status of mobile networks of the fifth generation and Internet of Things is given.