WorldWideScience

Sample records for human-computer communication channel

  1. Cooperation in human-computer communication

    OpenAIRE

    Kronenberg, Susanne

    2000-01-01

    The goal of this thesis is to simulate cooperation in human-computer communication to model the communicative interaction process of agents in natural dialogs in order to provide advanced human-computer interaction in that coherence is maintained between contributions of both agents, i.e. the human user and the computer. This thesis contributes to certain aspects of understanding and generation and their interaction in the German language. In spontaneous dialogs agents cooperate by the pro...

  2. Feedback Loops in Communication and Human Computing

    NARCIS (Netherlands)

    op den Akker, Hendrikus J.A.; Heylen, Dirk K.J.; Pantic, Maja; Pentland, Alex; Nijholt, Antinus; Huang, Thomas S.

    Building systems that are able to analyse communicative behaviours or take part in conversations requires a sound methodology in which the complex organisation of conversations is understood and tested on real-life samples. The data-driven approaches to human computing not only have a value for the

  3. Optical Communications Channel Combiner

    Science.gov (United States)

    Quirk, Kevin J.; Quirk, Kevin J.; Nguyen, Danh H.; Nguyen, Huy

    2012-01-01

    NASA has identified deep-space optical communications links as an integral part of a unified space communication network in order to provide data rates in excess of 100 Mb/s. The distances and limited power inherent in a deep-space optical downlink necessitate the use of photon-counting detectors and a power-efficient modulation such as pulse position modulation (PPM). For the output of each photodetector, whether from a separate telescope or a portion of the detection area, a communication receiver estimates a log-likelihood ratio for each PPM slot. To realize the full effective aperture of these receivers, their outputs must be combined prior to information decoding. A channel combiner was developed to synchronize the log-likelihood ratio (LLR) sequences of multiple receivers, and then combines these into a single LLR sequence for information decoding. The channel combiner synchronizes the LLR sequences of up to three receivers and then combines these into a single LLR sequence for output. The channel combiner has three channel inputs, each of which takes as input a sequence of four-bit LLRs for each PPM slot in a codeword via a XAUI 10 Gb/s quad optical fiber interface. The cross-correlation between the channels LLR time series are calculated and used to synchronize the sequences prior to combining. The output of the channel combiner is a sequence of four-bit LLRs for each PPM slot in a codeword via a XAUI 10 Gb/s quad optical fiber interface. The unit is controlled through a 1 Gb/s Ethernet UDP/IP interface. A deep-space optical communication link has not yet been demonstrated. This ground-station channel combiner was developed to demonstrate this capability and is unique in its ability to process such a signal.

  4. Quantum communication under channel uncertainty

    International Nuclear Information System (INIS)

    Noetzel, Janis Christian Gregor

    2012-01-01

    This work contains results concerning transmission of entanglement and subspaces as well as generation of entanglement in the limit of arbitrary many uses of compound- and arbitrarily varying quantum channels (CQC, AVQC). In both cases, the channel is described by a set of memoryless channels. Only forward communication between one sender and one receiver is allowed. A code is said to be ''good'' only, if it is ''good'' for every channel out of the set. Both settings describe a scenario, in which sender and receiver have only limited channel knowledge. For different amounts of information about the channel available to sender or receiver, coding theorems are proven for the CQC. For the AVQC, both deterministic and randomised coding schemes are considered. Coding theorems are proven, as well as a quantum analogue of the Ahlswede-dichotomy. The connection to zero-error capacities of stationary memoryless quantum channels is investigated. The notion of symmetrisability is defined and used for both classes of channels.

  5. Quantum communication under channel uncertainty

    Energy Technology Data Exchange (ETDEWEB)

    Noetzel, Janis Christian Gregor

    2012-09-06

    This work contains results concerning transmission of entanglement and subspaces as well as generation of entanglement in the limit of arbitrary many uses of compound- and arbitrarily varying quantum channels (CQC, AVQC). In both cases, the channel is described by a set of memoryless channels. Only forward communication between one sender and one receiver is allowed. A code is said to be ''good'' only, if it is ''good'' for every channel out of the set. Both settings describe a scenario, in which sender and receiver have only limited channel knowledge. For different amounts of information about the channel available to sender or receiver, coding theorems are proven for the CQC. For the AVQC, both deterministic and randomised coding schemes are considered. Coding theorems are proven, as well as a quantum analogue of the Ahlswede-dichotomy. The connection to zero-error capacities of stationary memoryless quantum channels is investigated. The notion of symmetrisability is defined and used for both classes of channels.

  6. Investigation Of Information Sources And Communication Channels ...

    African Journals Online (AJOL)

    Investigation Of Information Sources And Communication Channels In Ipm Rice ... the information accessibility of farmer groups seems as empowerment strategy. ... information sources and communication channels, in order of importance, ...

  7. Human Computer Music Performance

    OpenAIRE

    Dannenberg, Roger B.

    2012-01-01

    Human Computer Music Performance (HCMP) is the study of music performance by live human performers and real-time computer-based performers. One goal of HCMP is to create a highly autonomous artificial performer that can fill the role of a human, especially in a popular music setting. This will require advances in automated music listening and understanding, new representations for music, techniques for music synchronization, real-time human-computer communication, music generation, sound synt...

  8. Universal communication part II: channels with memory

    OpenAIRE

    Lomnitz, Yuval; Feder, Meir

    2012-01-01

    Consider communication over a channel whose probabilistic model is completely unknown vector-wise and is not assumed to be stationary. Communication over such channels is challenging because knowing the past does not indicate anything about the future. The existence of reliable feedback and common randomness is assumed. In a previous paper it was shown that the Shannon capacity cannot be attained, in general, if the channel is not known. An alternative notion of "capacity" was defined, as the...

  9. Benefits of Subliminal Feedback Loops in Human-Computer Interaction

    OpenAIRE

    Walter Ritter

    2011-01-01

    A lot of efforts have been directed to enriching human-computer interaction to make the user experience more pleasing or efficient. In this paper, we briefly present work in the fields of subliminal perception and affective computing, before we outline a new approach to add analog communication channels to the human-computer interaction experience. In this approach, in addition to symbolic predefined mappings of input to output, a subliminal feedback loop is used that provides feedback in evo...

  10. integrating indigenous and exogenous communication channels

    African Journals Online (AJOL)

    Prof. Adipala Ekwamu

    1Ministry of Agriculture and Food Security, Pesticide Control Board, Malawi. 2Ministry of ... noticed by the authors that local communication channels and folk media play an important role in CBAF, ... traditionally generate, store, share,.

  11. Cooperative communications hardware, channel and PHY

    CERN Document Server

    Dohler, Mischa

    2010-01-01

    Facilitating Cooperation for Wireless Systems Cooperative Communications: Hardware, Channel & PHY focuses on issues pertaining to the PHY layer of wireless communication networks, offering a rigorous taxonomy of this dispersed field, along with a range of application scenarios for cooperative and distributed schemes, demonstrating how these techniques can be employed. The authors discuss hardware, complexity and power consumption issues, which are vital for understanding what can be realized at the PHY layer, showing how wireless channel models differ from more traditional

  12. Human computer interaction and communication aids for hearing-impaired, deaf and deaf-blind people: Introduction to the special thematic session

    DEFF Research Database (Denmark)

    Bothe, Hans-Heinrich

    2008-01-01

    This paper gives ail overview and extends the Special Thematic Session (STS) oil research and development of technologies for hearing-impaired, deaf, and deaf-blind people. The topics of the session focus oil special equipment or services to improve communication and human computer interaction....... The papers are related to visual communication using captions, sign language, speech-reading, to vibro-tactile stimulation, or to general services for hearing-impaired persons....

  13. Concurrent signal combining and channel estimation in digital communications

    Science.gov (United States)

    Ormesher, Richard C [Albuquerque, NM; Mason, John J [Albuquerque, NM

    2011-08-30

    In the reception of digital information transmitted on a communication channel, a characteristic exhibited by the communication channel during transmission of the digital information is estimated based on a communication signal that represents the digital information and has been received via the communication channel. Concurrently with the estimating, the communication signal is used to decide what digital information was transmitted.

  14. Spatial Modulation in the Underwater Acoustic Communication Channel

    National Research Council Canada - National Science Library

    Kilfoyle, Daniel

    2000-01-01

    .... The technique, termed spatial modulation, seeks to control the spatial distribution of signal energy such that multiple parallel communication channels are supported by the single, physical ocean channel...

  15. New Channel Coding Methods for Satellite Communication

    Directory of Open Access Journals (Sweden)

    J. Sebesta

    2010-04-01

    Full Text Available This paper deals with the new progressive channel coding methods for short message transmission via satellite transponder using predetermined length of frame. The key benefits of this contribution are modification and implementation of a new turbo code and utilization of unique features with applications of methods for bit error rate estimation and algorithm for output message reconstruction. The mentioned methods allow an error free communication with very low Eb/N0 ratio and they have been adopted for satellite communication, however they can be applied for other systems working with very low Eb/N0 ratio.

  16. A private ultraviolet channel in visual communication.

    Science.gov (United States)

    Cummings, Molly E; Rosenthal, Gil G; Ryan, Michael J

    2003-01-01

    Although private communication is considered an important diversifying force in evolution, there is little direct behavioural evidence to support this notion. Here, we show that ultraviolet (UV) signalling in northern swordtails (Xiphophorus) affords a channel for communication that is not accessible to their major predator, Astyanax mexicanus, the Mexican tetra. Laboratory and field behavioural experiments with swordtails (X. nigrensis) and predators (A. mexicanus) demonstrate that male UV ornamentation significantly increases their attractiveness to females but not to this predator, which is less sensitive to UV. UV reflectance among swordtail species correlates positively with tetra densities across habitats, and visual contrast estimates suggest that UV signals are highly conspicuous to swordtails in their natural environment. Cross-species comparisons also support the hypothesis that natural selection drives the use of UV communication. We compared two species, one with high (X. nigrensis) and one with low (X. malinche) Mexican tetra densities. Xiphophorus nigrensis males reflect significantly more UV than X. malinche, exhibit significant UV sexual dimorphism, and UV is a salient component of the sexual communication system. In X. malinche, however, males reflect minimally in the UV, there is no UV sexual dimorphism, and UV does not play a part in its communication system. PMID:12803903

  17. A private ultraviolet channel in visual communication.

    Science.gov (United States)

    Cummings, Molly E; Rosenthal, Gil G; Ryan, Michael J

    2003-05-07

    Although private communication is considered an important diversifying force in evolution, there is little direct behavioural evidence to support this notion. Here, we show that ultraviolet (UV) signalling in northern swordtails (Xiphophorus) affords a channel for communication that is not accessible to their major predator, Astyanax mexicanus, the Mexican tetra. Laboratory and field behavioural experiments with swordtails (X. nigrensis) and predators (A. mexicanus) demonstrate that male UV ornamentation significantly increases their attractiveness to females but not to this predator, which is less sensitive to UV. UV reflectance among swordtail species correlates positively with tetra densities across habitats, and visual contrast estimates suggest that UV signals are highly conspicuous to swordtails in their natural environment. Cross-species comparisons also support the hypothesis that natural selection drives the use of UV communication. We compared two species, one with high (X. nigrensis) and one with low (X. malinche) Mexican tetra densities. Xiphophorus nigrensis males reflect significantly more UV than X. malinche, exhibit significant UV sexual dimorphism, and UV is a salient component of the sexual communication system. In X. malinche, however, males reflect minimally in the UV, there is no UV sexual dimorphism, and UV does not play a part in its communication system.

  18. Quantum communication using a multiqubit entangled channel

    Energy Technology Data Exchange (ETDEWEB)

    Ghose, Shohini, E-mail: sghose@wlu.ca [Department of Physics and Computer Science, Wilfrid Laurier University, Waterloo, Ontario (Canada); Institute for Quantum Computing, University of Waterloo, Ontario (Canada); Hamel, Angele [Department of Physics and Computer Science, Wilfrid Laurier University, Waterloo, Ontario (Canada)

    2015-12-31

    We describe a protocol in which two senders each teleport a qubit to a receiver using a multiqubit entangled state. The multiqubit channel used for teleportation is genuinely 4-qubit entangled and is not equivalent to a product of maximally entangled Bell pairs under local unitary operations. We discuss a scenario in which both senders must participate for the qubits to be successfully teleported. Such an all-or-nothing scheme cannot be implemented with standard two-qubit entangled Bell pairs and can be useful for different communication and computing tasks.

  19. Multicarrier chaotic communications in multipath fading channels without channel estimation

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Shilian, E-mail: wangsl@nudt.edu.cn; Zhang, Zhili [College of Electrical Science and Engineering, National University of Defense Technology, Changsha, 410073, P R China (China)

    2015-01-15

    A multi-carrier chaotic shift keying(MC-CSK) communication scheme with low probability of interception(LPI) is proposed in this article. We apply chaotic spreading sequences in the frequency domain, mapping a different chip of a chaotic sequence to an individual orthogonal frequency division multiplexing(OFDM) subcarrier. In each block size of $M$ OFDM symbols, we use one pilot OFDM symbol inserted time-spaced in all-frequency to transmit the reference chaotic signal and use the other M-1 OFDM symbols to transmit the information-bearing signals each spreaded by the reference chaotic signal. At the receiver, we construct a differential detector after DFT and recover the information bits from the correlations between the pilot OFDM symbol and the other M-1 OFDM symbols in each block size of M. Performance analysis and computer simulations show that the MC-CSK outperforms differential chaos shift keying(DCSK) in AWGN channels with high bandwidth efficiency for the block size of M=2 and that the MC-CSK exploits effectively the frequent diversity of the multipath channel.

  20. Multicarrier chaotic communications in multipath fading channels without channel estimation

    Directory of Open Access Journals (Sweden)

    Shilian Wang

    2015-01-01

    Full Text Available A multi-carrier chaotic shift keying(MC-CSK communication scheme with low probability of interception(LPI is proposed in this article. We apply chaotic spreading sequences in the frequency domain, mapping a different chip of a chaotic sequence to an individual orthogonal frequency division multiplexing(OFDM subcarrier. In each block size of $M$ OFDM symbols, we use one pilot OFDM symbol inserted time-spaced in all-frequency to transmit the reference chaotic signal and use the other M-1 OFDM symbols to transmit the information-bearing signals each spreaded by the reference chaotic signal. At the receiver, we construct a differential detector after DFT and recover the information bits from the correlations between the pilot OFDM symbol and the other M-1 OFDM symbols in each block size of M. Performance analysis and computer simulations show that the MC-CSK outperforms differential chaos shift keying(DCSK in AWGN channels with high bandwidth efficiency for the block size of M=2 and that the MC-CSK exploits effectively the frequent diversity of the multipath channel.

  1. Channel coding techniques for wireless communications

    CERN Document Server

    Deergha Rao, K

    2015-01-01

    The book discusses modern channel coding techniques for wireless communications such as turbo codes, low-density parity check (LDPC) codes, space–time (ST) coding, RS (or Reed–Solomon) codes and convolutional codes. Many illustrative examples are included in each chapter for easy understanding of the coding techniques. The text is integrated with MATLAB-based programs to enhance the understanding of the subject’s underlying theories. It includes current topics of increasing importance such as turbo codes, LDPC codes, Luby transform (LT) codes, Raptor codes, and ST coding in detail, in addition to the traditional codes such as cyclic codes, BCH (or Bose–Chaudhuri–Hocquenghem) and RS codes and convolutional codes. Multiple-input and multiple-output (MIMO) communications is a multiple antenna technology, which is an effective method for high-speed or high-reliability wireless communications. PC-based MATLAB m-files for the illustrative examples are provided on the book page on Springer.com for free dow...

  2. Reliable quantum communication over a quantum relay channel

    Energy Technology Data Exchange (ETDEWEB)

    Gyongyosi, Laszlo, E-mail: gyongyosi@hit.bme.hu [Quantum Technologies Laboratory, Department of Telecommunications, Budapest University of Technology and Economics, 2 Magyar tudosok krt, Budapest, H-1117, Hungary and Information Systems Research Group, Mathematics and Natural Sciences, Hungarian Ac (Hungary); Imre, Sandor [Quantum Technologies Laboratory, Department of Telecommunications, Budapest University of Technology and Economics, 2 Magyar tudosok krt, Budapest, H-1117 (Hungary)

    2014-12-04

    We show that reliable quantum communication over an unreliable quantum relay channels is possible. The coding scheme combines the results on the superadditivity of quantum channels and the efficient quantum coding approaches.

  3. Propagation channel characterization, parameter estimation, and modeling for wireless communications

    CERN Document Server

    Yin, Xuefeng

    2016-01-01

    Thoroughly covering channel characteristics and parameters, this book provides the knowledge needed to design various wireless systems, such as cellular communication systems, RFID and ad hoc wireless communication systems. It gives a detailed introduction to aspects of channels before presenting the novel estimation and modelling techniques which can be used to achieve accurate models. To systematically guide readers through the topic, the book is organised in three distinct parts. The first part covers the fundamentals of the characterization of propagation channels, including the conventional single-input single-output (SISO) propagation channel characterization as well as its extension to multiple-input multiple-output (MIMO) cases. Part two focuses on channel measurements and channel data post-processing. Wideband channel measurements are introduced, including the equipment, technology and advantages and disadvantages of different data acquisition schemes. The channel parameter estimation methods are ...

  4. A Survey of Channel Modeling for UAV Communications

    KAUST Repository

    Khuwaja, Aziz Altaf; Chen, Yunfei; Zhao, Nan; Alouini, Mohamed-Slim; Dobbins, Paul

    2018-01-01

    Unmanned aerial vehicles (UAVs) have gained great interest for rapid deployment in both civil and military applications. UAV communication has its own distinctive channel characteristics compared with widely used cellular and satellite systems. Thus, accurate channel characterization is crucial for the performance optimization and design of efficient UAV communication systems. However, several challenges exist in UAV channel modeling. For example, propagation characteristics of UAV channels are still less explored for spatial and temporal variations in non-stationary channels. Also, airframe shadowing has not yet been investigated for small size rotary UAVs. This paper provides an extensive survey on the measurement campaigns launched for UAV channel modeling using low altitude platforms and discusses various channel characterization efforts. We also review the contemporary perspective of UAV channel modeling approaches and outline some future research challenges in this domain.

  5. A Survey of Channel Modeling for UAV Communications

    KAUST Repository

    Khuwaja, Aziz Altaf

    2018-01-23

    Unmanned aerial vehicles (UAVs) have gained great interest for rapid deployment in both civil and military applications. UAV communication has its own distinctive channel characteristics compared with widely used cellular and satellite systems. Thus, accurate channel characterization is crucial for the performance optimization and design of efficient UAV communication systems. However, several challenges exist in UAV channel modeling. For example, propagation characteristics of UAV channels are still less explored for spatial and temporal variations in non-stationary channels. Also, airframe shadowing has not yet been investigated for small size rotary UAVs. This paper provides an extensive survey on the measurement campaigns launched for UAV channel modeling using low altitude platforms and discusses various channel characterization efforts. We also review the contemporary perspective of UAV channel modeling approaches and outline some future research challenges in this domain.

  6. Improved Sparse Channel Estimation for Cooperative Communication Systems

    Directory of Open Access Journals (Sweden)

    Guan Gui

    2012-01-01

    Full Text Available Accurate channel state information (CSI is necessary at receiver for coherent detection in amplify-and-forward (AF cooperative communication systems. To estimate the channel, traditional methods, that is, least squares (LS and least absolute shrinkage and selection operator (LASSO, are based on assumptions of either dense channel or global sparse channel. However, LS-based linear method neglects the inherent sparse structure information while LASSO-based sparse channel method cannot take full advantage of the prior information. Based on the partial sparse assumption of the cooperative channel model, we propose an improved channel estimation method with partial sparse constraint. At first, by using sparse decomposition theory, channel estimation is formulated as a compressive sensing problem. Secondly, the cooperative channel is reconstructed by LASSO with partial sparse constraint. Finally, numerical simulations are carried out to confirm the superiority of proposed methods over global sparse channel estimation methods.

  7. Acoustic MIMO communications in a very shallow water channel

    Science.gov (United States)

    Zhou, Yuehai; Cao, Xiuling; Tong, Feng

    2015-12-01

    Underwater acoustic channels pose significant difficulty for the development of high speed communication due to highly limited band-width as well as hostile multipath interference. Enlightened by rapid progress of multiple input multiple output (MIMO) technologies in wireless communication scenarios, MIMO systems offer a potential solution by enabling multiple spatially parallel communication channels to improve communication performance as well as capacity. For MIMO acoustic communications, deep sea channels offer substantial spatial diversity among multiple channels that can be exploited to address simultaneous multipath and co-channel interference. At the same time, there are increasing requirements for high speed underwater communication in very shallow water area (for example, a depth less than 10 m). In this paper, a space-time multichannel adaptive receiver consisting of multiple decision feedback equalizers (DFE) is adopted as the receiver for a very shallow water MIMO acoustic communication system. The performance of multichannel DFE receivers with relatively small number of receiving elements are analyzed and compared with that of the multichannel time reversal receiver to evaluate the impact of limited spatial diversity on multi-channel equalization and time reversal processing. The results of sea trials in a very shallow water channel are presented to demonstrate the feasibility of very shallow water MIMO acoustic communication.

  8. Optimization of Communication in Noisy Quantum Channels

    National Research Council Canada - National Science Library

    Ruskai, Mary

    2002-01-01

    .... This project has been concerned with the analysis of mathematical models of noise for qubit channels, with the capacity of qubit channels used to transmit classical information, and with exchange...

  9. Quantum Communication Scheme Using Non-symmetric Quantum Channel

    International Nuclear Information System (INIS)

    Cao Haijing; Chen Zhonghua; Song Heshan

    2008-01-01

    A theoretical quantum communication scheme based on entanglement swapping and superdense coding is proposed with a 3-dimensional Bell state and 2-dimensional Bell state function as quantum channel. quantum key distribution and quantum secure direct communication can be simultaneously accomplished in the scheme. The scheme is secure and has high source capacity. At last, we generalize the quantum communication scheme to d-dimensional quantum channel

  10. A Simulator of Periodically Switching Channels for Power Line Communications

    Science.gov (United States)

    Hayasaki, Taro; Umehara, Daisuke; Denno, Satoshi; Morikura, Masahiro

    An indoor power line is one of the most attractive media for in-home networks. However, there are many technical problems for achieving in-home power line communication (PLC) with high rate and high reliability. One of such problem is the degradation in the performance of the in-home PLC caused by periodically time-varying channel responses, particularly when connecting the switching power supply equipment. We present a measurement method for power line channel responses and reveal the switching of the channel responses synchronized with power-frequency voltage when connecting switching power supply equipment in sending or receiving outlets. In this paper, we term them periodically switching channel responses. The performance of PLC adapters is seriously affected by the periodically switching channel responses. Therefore, we provide a modeling of the periodically switching channel responses by using finite impulse response (FIR) filters with a shared channel memory and construct a simulator for in-home power line channels including the periodically switching channel responses in order to evaluate the various communication systems through the power line. We present the validity of the proposed simulator through the performance evaluation of OFDM/64QAM over periodically switching channels with additive white Gaussian noise. Furthermore, we evaluate the influence of the periodically switching channel responses on the communication quality of a time-invariant modulation scheme by using the proposed simulator.

  11. Customer Engagement Tool (Multi Channel Communication)

    Data.gov (United States)

    Social Security Administration — Add new infrastructure within SSA's Enterprise Architecture to allow interactions over multiple, yet to be defined, channels. Possibilities include: Provide a portal...

  12. On the Secrecy Capacity of MISO Visible Light Communication Channels

    KAUST Repository

    Arfaoui, Mohamed Amine; Rezki, Zouheir; Ghrayeb, Ali; Alouini, Mohamed-Slim

    2017-01-01

    We study the secrecy capacity of the multiple- input single-output (MISO) Gaussian wiretap visible light communication (VLC) channel. We study a typical VLC scenario with one transmitter, one legitimate receiver, and one eavesdropper. Specifically

  13. Remote optimal state estimation over communication channels with random delays

    KAUST Repository

    Mahmoud, Magdi S.; Al-Sunni, Fouad; Liu, Bo

    2014-01-01

    This paper considers the optimal estimation of linear systems over unreliable communication channels with random delays. In this work, it is assumed that the system to be estimated is far away from the filter. The observations of the system

  14. A communication-channel-based representation system for software

    NARCIS (Netherlands)

    Demirezen, Zekai; Tanik, Murat M.; Aksit, Mehmet; Skjellum, Anthony

    We observed that before initiating software development the objectives are minimally organized and developers introduce comparatively higher organization throughout the design process. To be able to formally capture this observation, a new communication channel representation system for software is

  15. SystemC modelling of wireless communication channel

    Science.gov (United States)

    Conti, Massimo; Orcioni, Simone

    2011-05-01

    This paper presents the definition in SystemC of wireless channels at different levels of abstraction. The different levels of description of the wireless channel can be easily interchanged allowing the reuse of the application and baseband layers in a high level analysis of the network or in a deep analysis of the communication between the wireless devices.

  16. The role of digital channels in industrial marketing communications

    OpenAIRE

    Karjaluoto, Heikki; Mustonen, Nora; Ulkuniemi, Pauliina

    2015-01-01

    Purpose – The purpose of this research is to investigate industrial marketing communications tools and the role of digital channels. The research draws from the literature on industrial marketing communications to examine its goals and intended utilization in industrial firms. Design/methodology/approach – An empirical multiple case study conducted among six industrial firms examines the current state of digital marketing communications (DMC). Findings – The study gleans thre...

  17. KIR channels tune electrical communication in cerebral arteries

    DEFF Research Database (Denmark)

    Sancho, Maria; Samson, Nina C; Hald, Bjorn O

    2017-01-01

    The conducted vasomotor response reflects electrical communication in the arterial wall and the distance signals spread is regulated by three factors including resident ion channels. This study defined the role of inward-rectifying K(+) channels (KIR) in governing electrical communication along...... hamster cerebral arteries. Focal KCl application induced a vasoconstriction that conducted robustly, indicative of electrical communication among cells. Inhibiting dominant K(+) conductances had no attenuating effect, the exception being Ba(2+) blockade of KIR Electrophysiology and Q-PCR analysis...... and the increased feedback arising from voltage-dependent-K(+) channels. In summary, this study shows that two KIR populations work collaboratively to govern electrical communication and the spread of vasomotor responses along cerebral arteries....

  18. Information transmission and recovery in neural communications channels

    International Nuclear Information System (INIS)

    Eguia, M. C.; Rabinovich, M. I.; Abarbanel, H. D. I.

    2000-01-01

    Biological neural communications channels transport environmental information from sensors through chains of active dynamical neurons to neural centers for decisions and actions to achieve required functions. These kinds of communications channels are able to create information and to transfer information from one time scale to the other because of the intrinsic nonlinear dynamics of the component neurons. We discuss a very simple neural information channel composed of sensory input in the form of a spike train that arrives at a model neuron, then moves through a realistic synapse to a second neuron where the information in the initial sensory signal is read. Our model neurons are four-dimensional generalizations of the Hindmarsh-Rose neuron, and we use a model of chemical synapse derived from first-order kinetics. The four-dimensional model neuron has a rich variety of dynamical behaviors, including periodic bursting, chaotic bursting, continuous spiking, and multistability. We show that, for many of these regimes, the parameters of the chemical synapse can be tuned so that information about the stimulus that is unreadable at the first neuron in the channel can be recovered by the dynamical activity of the synapse and the second neuron. Information creation by nonlinear dynamical systems that allow chaotic oscillations is familiar in their autonomous oscillations. It is associated with the instabilities that lead to positive Lyapunov exponents in their dynamical behavior. Our results indicate how nonlinear neurons acting as input/output systems along a communications channel can recover information apparently ''lost'' in earlier junctions on the channel. Our measure of information transmission is the average mutual information between elements, and because the channel is active and nonlinear, the average mutual information between the sensory source and the final neuron may be greater than the average mutual information at an earlier neuron in the channel. This

  19. Multi-carrier Communications over Time-varying Acoustic Channels

    Science.gov (United States)

    Aval, Yashar M.

    Acoustic communication is an enabling technology for many autonomous undersea systems, such as those used for ocean monitoring, offshore oil and gas industry, aquaculture, or port security. There are three main challenges in achieving reliable high-rate underwater communication: the bandwidth of acoustic channels is extremely limited, the propagation delays are long, and the Doppler distortions are more pronounced than those found in wireless radio channels. In this dissertation we focus on assessing the fundamental limitations of acoustic communication, and designing efficient signal processing methods that cam overcome these limitations. We address the fundamental question of acoustic channel capacity (achievable rate) for single-input-multi-output (SIMO) acoustic channels using a per-path Rician fading model, and focusing on two scenarios: narrowband channels where the channel statistics can be approximated as frequency- independent, and wideband channels where the nominal path loss is frequency-dependent. In each scenario, we compare several candidate power allocation techniques, and show that assigning uniform power across all frequencies for the first scenario, and assigning uniform power across a selected frequency-band for the second scenario, are the best practical choices in most cases, because the long propagation delay renders the feedback information outdated for power allocation based on the estimated channel response. We quantify our results using the channel information extracted form the 2010 Mobile Acoustic Communications Experiment (MACE'10). Next, we focus on achieving reliable high-rate communication over underwater acoustic channels. Specifically, we investigate orthogonal frequency division multiplexing (OFDM) as the state-of-the-art technique for dealing with frequency-selective multipath channels, and propose a class of methods that compensate for the time-variation of the underwater acoustic channel. These methods are based on multiple

  20. Relativistic quantum channel of communication through field quanta

    International Nuclear Information System (INIS)

    Cliche, M.; Kempf, A.

    2010-01-01

    Setups in which a system Alice emits field quanta that a system Bob receives are prototypical for wireless communication and have been extensively studied. In the most basic setup, Alice and Bob are modeled as Unruh-DeWitt detectors for scalar quanta, and the only noise in their communication is due to quantum fluctuations. For this basic setup, we construct the corresponding information-theoretic quantum channel. We calculate the classical channel capacity as a function of the spacetime separation, and we confirm that the classical as well as the quantum channel capacity are strictly zero for spacelike separations. We show that this channel can be used to entangle Alice and Bob instantaneously. Alice and Bob are shown to extract this entanglement from the vacuum through a Casimir-Polder effect.

  1. Transitions in the Communication Capacity of Dissipative Qubit Channels

    Science.gov (United States)

    Daems, D.

    2009-05-01

    The information transmission is studied for quantum channels in which the noise includes dissipative effects, more specifically, nonunitality. Noise is usually a nuisance but can sometimes be helpful. For these channels, the communication capacity is shown to increase with the dissipative component of the noise and may exhibit transitions beyond which it increases faster. The optimal states are constructed analytically as well as the pertaining “phase” diagram.

  2. Robust Quantum Secure Direct Communication over Collective Rotating Channel

    International Nuclear Information System (INIS)

    Qin Sujuan; Gao Fei; Wen Qiaoyan; Zhu Fuchen

    2010-01-01

    A quantum secure direct communication protocol over a collective rotating channel is proposed. The protocol encodes logical bits in noiseless subspaces, and so it can function over a quantum channel subjected to an arbitrary degree of collective rotating noise. Although entangled states are used, both the sender and receiver are only required to perform single-particle product measurement or Pauli operations. The protocol is feasible with present-day technique. (general)

  3. Achieving single channel, full duplex wireless communication

    KAUST Repository

    Choi, Jung Il; Jain, Mayank; Srinivasan, Kannan; Levis, Phil; Katti, Sachin

    2010-01-01

    This paper discusses the design of a single channel full-duplex wireless transceiver. The design uses a combination of RF and baseband techniques to achieve full-duplexing with minimal effect on link reliability. Experiments on real nodes show the full-duplex prototype achieves median performance that is within 8% of an ideal full-duplexing system. This paper presents Antenna Cancellation, a novel technique for self-interference cancellation. In conjunction with existing RF interference cancellation and digital baseband interference cancellation, antenna cancellation achieves the amount of self-interference cancellation required for full-duplex operation. The paper also discusses potential MAC and network gains with full-duplexing. It suggests ways in which a full-duplex system can solve some important problems with existing wireless systems including hidden terminals, loss of throughput due to congestion, and large end-to-end delays. Copyright 2010 ACM.

  4. Digital advertising in cross-channel communications

    Directory of Open Access Journals (Sweden)

    A. V. Mordovin

    2017-01-01

    Full Text Available Advertising has passed a long way of development and today it is no longer limited to the printed press, static billboards, radio and television commercials. Digital technology has started a completely new era of digital advertising, which allows marketers and advertisers to target audiences with great precision. To meet the needs and expectations of customers who gain new personal experience through involvement in the process of continuous network communication advertisers make use of digital technologies that continue to develop intensively. Based on technological advances, new advertising technologies employ tracking methods to produce tailor-made advertisements that meet specific needs of customers, and new advertising platforms that can host new types of ads with dynamic content provide endless opportunities for marketers and advertisers. This paper will explore the key trends in the segment of digital advertising. In the process of this research methods of desk research and expert interviews were used. The received results can be used for updating of strategy and structure of marketing communications of the enterprises, their marketing budgets; in the educational process and for the further deepening of scientific and applied research.

  5. Ubiquitous human computing.

    Science.gov (United States)

    Zittrain, Jonathan

    2008-10-28

    Ubiquitous computing means network connectivity everywhere, linking devices and systems as small as a drawing pin and as large as a worldwide product distribution chain. What could happen when people are so readily networked? This paper explores issues arising from two possible emerging models of ubiquitous human computing: fungible networked brainpower and collective personal vital sign monitoring.

  6. Assessing the Role of College as a Sustainability Communication Channel

    Science.gov (United States)

    Lertpratchya, Alisa P.; Besley, John C.; Zwickle, Adam; Takahashi, Bruno; Whitley, Cameron Thomas

    2017-01-01

    Purpose: The purpose of this study is to assess the effectiveness of higher education institution as a sustainability communication channel. The theory of planned behavior was used to examine the degree to which a student's tenure at a large university with active and visible sustainability initiatives is associated with changes in views about…

  7. Optimal channel utilization and service protection in cellular communication systems

    DEFF Research Database (Denmark)

    Iversen, Villy Bæk

    1997-01-01

    In mobile communications an efficient utilization of the channels is of great importance.In this paper we consider the basic principles for obtaining the maximum utilization, and we study strategies for obtaining these limits.In general a high degree of sharing is efficient, but requires service...... protection mechanisms for protecting services and subscriber groups.We study cellular systems with overlaid cells, and the effect of overlapping cells, and we show that by dynamic channel allocation we obtain a high utilization.The models are generalizations of the Erlang-B formula, and can be evaluated...

  8. Impact of a bone conduction communication channel on multichannel communication system effectiveness.

    Science.gov (United States)

    Blue, Misty; McBride, Maranda; Weatherless, Rachel; Letowski, Tomasz

    2013-04-01

    In this study, the impact of including a bone conduction transducer in a three-channel spatialized communication system was investigated. Several military and security forces situations require concurrent listening to three or more radio channels. In such radio systems, spatial separation between three concurrent radio channels can be achieved by delivering separate signals to the left and right earphone independently and both earphones simultaneously. This method appears to be effective; however, the use of bone conduction as one channel may provide both operational and performance benefits. Three three-channel communication systems were used to collect speech intelligibility data from 18 listeners (System I, three loudspeakers; System 2, stereo headphones; System 3, stereo headphones and a bone conduction vibrator). Each channel presented signals perceived to originate from separate locations. Volunteers listened to three sets of competing sentences and identified a number, color, and object spoken in the target sentence. Each listener participated in three trials (one per system). Each trial consisted of 48 competing sentence sets. Systems 2 and 3 were more intelligible than System I. Systems 2 and 3 were overall equally intelligible; however, the intelligibility of all three channels was significantly more balanced in System 3. Replacing an air conduction transducer with a bone conduction transducer in a multichannel audio device can provide a more effective and balanced simultaneous monitoring auditory environment. These results have important design and implementation implications for spatial auditory communication equipment.

  9. Handbook of human computation

    CERN Document Server

    Michelucci, Pietro

    2013-01-01

    This volume addresses the emerging area of human computation, The chapters, written by leading international researchers, explore existing and future opportunities to combine the respective strengths of both humans and machines in order to create powerful problem-solving capabilities. The book bridges scientific communities, capturing and integrating the unique perspective and achievements of each. It coalesces contributions from industry and across related disciplines in order to motivate, define, and anticipate the future of this exciting new frontier in science and cultural evolution. Reade

  10. Dynamic Propagation Channel Characterization and Modeling for Human Body Communication

    Science.gov (United States)

    Nie, Zedong; Ma, Jingjing; Li, Zhicheng; Chen, Hong; Wang, Lei

    2012-01-01

    This paper presents the first characterization and modeling of dynamic propagation channels for human body communication (HBC). In-situ experiments were performed using customized transceivers in an anechoic chamber. Three HBC propagation channels, i.e., from right leg to left leg, from right hand to left hand and from right hand to left leg, were investigated under thirty-three motion scenarios. Snapshots of data (2,800,000) were acquired from five volunteers. Various path gains caused by different locations and movements were quantified and the statistical distributions were estimated. In general, for a given reference threshold è = −10 dB, the maximum average level crossing rate of the HBC was approximately 1.99 Hz, the maximum average fade time was 59.4 ms, and the percentage of bad channel duration time was less than 4.16%. The HBC exhibited a fade depth of −4 dB at 90% complementary cumulative probability. The statistical parameters were observed to be centered for each propagation channel. Subsequently a Fritchman model was implemented to estimate the burst characteristics of the on-body fading. It was concluded that the HBC is motion-insensitive, which is sufficient for reliable communication link during motions, and therefore it has great potential for body sensor/area networks. PMID:23250278

  11. Analysis of different communication channels for promoting hygiene behaviour.

    Science.gov (United States)

    Pinfold, J V

    1999-10-01

    A hygiene intervention study reduced diarrhoeal disease transmission in rural northeast Thailand by promoting hand-washing and dish-washing behaviour. Most of the target audience did not recognize a connection between these behaviours and diarrhoeal disease, and therefore a social marketing approach was used to develop a campaign promoting behaviours through a variety of communication channels keeping messages simple and in terms understood by the community. Overall, there was a strong correlation between the number of communication channels remembered by respondents and their knowledge score, with passive channels of printed media such as stickers, posters and leaflets associated with significantly higher scores than other channels. However, the same did not hold true for improvement in actual behaviour and only 'school children' were associated with significantly less fingertip contamination. In-depth interviews with conformers and non-conformers suggested that although most knew the intervention messages well enough, the importance they attached to them differed markedly. Thus dissemination of message knowledge was not consistent with the process of dissemination of actual practice. Where a strong sense of community spirit existed, friends, relatives and neighbours were more likely to discuss intervention activities with each other.

  12. 39 CFR 223.2 - Channels of communication, headquarters with area offices.

    Science.gov (United States)

    2010-07-01

    ... RELATIONSHIPS AND COMMUNICATION CHANNELS § 223.2 Channels of communication, headquarters with area offices. (a... 39 Postal Service 1 2010-07-01 2010-07-01 false Channels of communication, headquarters with area...). Whether published on paper or online, such policies must be coordinated with other appropriate...

  13. Human-computer interaction : Guidelines for web animation

    OpenAIRE

    Galyani Moghaddam, Golnessa; Moballeghi, Mostafa

    2006-01-01

    Human-computer interaction in the large is an interdisciplinary area which attracts researchers, educators, and practioners from many differenf fields. Human-computer interaction studies a human and a machine in communication, it draws from supporting knowledge on both the machine and the human side. This paper is related to the human side of human-computer interaction and focuses on animations. The growing use of animation in Web pages testifies to the increasing ease with which such multim...

  14. Bandwidth efficient channel estimation method for airborne hyperspectral data transmission in sparse doubly selective communication channels

    Science.gov (United States)

    Vahidi, Vahid; Saberinia, Ebrahim; Regentova, Emma E.

    2017-10-01

    A channel estimation (CE) method based on compressed sensing (CS) is proposed to estimate the sparse and doubly selective (DS) channel for hyperspectral image transmission from unmanned aircraft vehicles to ground stations. The proposed method contains three steps: (1) the priori estimate of the channel by orthogonal matching pursuit (OMP), (2) calculation of the linear minimum mean square error (LMMSE) estimate of the received pilots given the estimated channel, and (3) estimate of the complex amplitudes and Doppler shifts of the channel using the enhanced received pilot data applying a second round of a CS algorithm. The proposed method is named DS-LMMSE-OMP, and its performance is evaluated by simulating transmission of AVIRIS hyperspectral data via the communication channel and assessing their fidelity for the automated analysis after demodulation. The performance of the DS-LMMSE-OMP approach is compared with that of two other state-of-the-art CE methods. The simulation results exhibit up to 8-dB figure of merit in the bit error rate and 50% improvement in the hyperspectral image classification accuracy.

  15. Mutual information against correlations in binary communication channels.

    Science.gov (United States)

    Pregowska, Agnieszka; Szczepanski, Janusz; Wajnryb, Eligiusz

    2015-05-19

    Explaining how the brain processing is so fast remains an open problem (van Hemmen JL, Sejnowski T., 2004). Thus, the analysis of neural transmission (Shannon CE, Weaver W., 1963) processes basically focuses on searching for effective encoding and decoding schemes. According to the Shannon fundamental theorem, mutual information plays a crucial role in characterizing the efficiency of communication channels. It is well known that this efficiency is determined by the channel capacity that is already the maximal mutual information between input and output signals. On the other hand, intuitively speaking, when input and output signals are more correlated, the transmission should be more efficient. A natural question arises about the relation between mutual information and correlation. We analyze the relation between these quantities using the binary representation of signals, which is the most common approach taken in studying neuronal processes of the brain. We present binary communication channels for which mutual information and correlation coefficients behave differently both quantitatively and qualitatively. Despite this difference in behavior, we show that the noncorrelation of binary signals implies their independence, in contrast to the case for general types of signals. Our research shows that the mutual information cannot be replaced by sheer correlations. Our results indicate that neuronal encoding has more complicated nature which cannot be captured by straightforward correlations between input and output signals once the mutual information takes into account the structure and patterns of the signals.

  16. Measurement and Modeling of Narrowband Channels for Ultrasonic Underwater Communications

    Directory of Open Access Journals (Sweden)

    Francisco J. Cañete

    2016-02-01

    Full Text Available Underwater acoustic sensor networks are a promising technology that allow real-time data collection in seas and oceans for a wide variety of applications. Smaller size and weight sensors can be achieved with working frequencies shifted from audio to the ultrasonic band. At these frequencies, the fading phenomena has a significant presence in the channel behavior, and the design of a reliable communication link between the network sensors will require a precise characterization of it. Fading in underwater channels has been previously measured and modeled in the audio band. However, there have been few attempts to study it at ultrasonic frequencies. In this paper, a campaign of measurements of ultrasonic underwater acoustic channels in Mediterranean shallow waters conducted by the authors is presented. These measurements are used to determine the parameters of the so-called κ-μ shadowed distribution, a fading model with a direct connection to the underlying physical mechanisms. The model is then used to evaluate the capacity of the measured channels with a closed-form expression.

  17. Optimal state estimation over communication channels with random delays

    KAUST Repository

    Mahmoud, Magdi S.; Liu, Bo

    2013-01-01

    This paper is concerned with the optimal estimation of linear systems over unreliable communication channels with random delays. The measurements are delivered without time stamp, and the probabilities of time delays are assumed to be known. Since the estimation is time-driven, the actual time delays are converted into virtual time delays among the formulation. The receiver of estimation node stores the sum of arrived measurements between two adjacent processing time instants and also counts the number of arrived measurements. The original linear system is modeled as an extended system with uncertain observation to capture the feature of communication, then the optimal estimation algorithm of systems with uncertain observations is proposed. Additionally, a numerical simulation is presented to show the performance of this work. © 2013 The Franklin Institute.

  18. Remote optimal state estimation over communication channels with random delays

    KAUST Repository

    Mahmoud, Magdi S.

    2014-01-22

    This paper considers the optimal estimation of linear systems over unreliable communication channels with random delays. In this work, it is assumed that the system to be estimated is far away from the filter. The observations of the system are capsulized without time stamp and then transmitted to the network node at which the filter is located. The probabilities of time delays are assumed to be known. The event-driven estimation scheme is applied in this paper and the estimate of the states is updated only at each time instant when any measurement arrives. To capture the feature of communication, the system considered is augmented, and the arrived measurements are regarded as the uncertain observations of the augmented system. The corresponding optimal estimation algorithm is proposed and additionally, a numerical simulation represents the performance of this work. © 2014 The authors. Published by Oxford University Press on behalf of the Institute of Mathematics and its Applications. All rights reserved.

  19. Optimal state estimation over communication channels with random delays

    KAUST Repository

    Mahmoud, Magdi S.

    2013-04-01

    This paper is concerned with the optimal estimation of linear systems over unreliable communication channels with random delays. The measurements are delivered without time stamp, and the probabilities of time delays are assumed to be known. Since the estimation is time-driven, the actual time delays are converted into virtual time delays among the formulation. The receiver of estimation node stores the sum of arrived measurements between two adjacent processing time instants and also counts the number of arrived measurements. The original linear system is modeled as an extended system with uncertain observation to capture the feature of communication, then the optimal estimation algorithm of systems with uncertain observations is proposed. Additionally, a numerical simulation is presented to show the performance of this work. © 2013 The Franklin Institute.

  20. Analysis of D2D Communications over Gamma/Nakagami Fading Channels

    Directory of Open Access Journals (Sweden)

    Z. Hussain

    2018-04-01

    Full Text Available In this paper, we investigate the outage probability, channel capacity and symbol error rate (SER performance of device-to-device (D2D communication systems. The D2D communication system is affected by several co-channel interferers. Gamma fading channel is considered for the D2D communication system. The channel for the co-channel interference is assumed to be Nakagami faded. An expression for the probability density function (PDF of the signal-to-interference ratio (SIR is presented. The PDF is a function of distances between various devices in the D2D system, path-loss, channel fading conditions and signal powers. Based on the PDF expression, we present the expressions for the outage, channel capacity and SER. With the help of numerical results the performance of D2D communication system is discussed under various conditions of interference, path-loss and channel fading.

  1. Efficient Weibull channel model for salinity induced turbulent underwater wireless optical communications

    KAUST Repository

    Oubei, Hassan M.; Zedini, Emna; Elafandy, Rami T.; Kammoun, Abla; Ng, Tien Khee; Alouini, Mohamed-Slim; Ooi, Boon S.

    2017-01-01

    Recent advances in underwater wireless optical communications necessitate a better understanding of the underwater channel. We propose the Weibull model to characterize the fading of salinity induced turbulent underwater wireless optical channels

  2. Equalization and detection for digital communication over nonlinear bandlimited satellite communication channels. Ph.D. Thesis

    Science.gov (United States)

    Gutierrez, Alberto, Jr.

    1995-01-01

    This dissertation evaluates receiver-based methods for mitigating the effects due to nonlinear bandlimited signal distortion present in high data rate satellite channels. The effects of the nonlinear bandlimited distortion is illustrated for digitally modulated signals. A lucid development of the low-pass Volterra discrete time model for a nonlinear communication channel is presented. In addition, finite-state machine models are explicitly developed for a nonlinear bandlimited satellite channel. A nonlinear fixed equalizer based on Volterra series has previously been studied for compensation of noiseless signal distortion due to a nonlinear satellite channel. This dissertation studies adaptive Volterra equalizers on a downlink-limited nonlinear bandlimited satellite channel. We employ as figure of merits performance in the mean-square error and probability of error senses. In addition, a receiver consisting of a fractionally-spaced equalizer (FSE) followed by a Volterra equalizer (FSE-Volterra) is found to give improvement beyond that gained by the Volterra equalizer. Significant probability of error performance improvement is found for multilevel modulation schemes. Also, it is found that probability of error improvement is more significant for modulation schemes, constant amplitude and multilevel, which require higher signal to noise ratios (i.e., higher modulation orders) for reliable operation. The maximum likelihood sequence detection (MLSD) receiver for a nonlinear satellite channel, a bank of matched filters followed by a Viterbi detector, serves as a probability of error lower bound for the Volterra and FSE-Volterra equalizers. However, this receiver has not been evaluated for a specific satellite channel. In this work, an MLSD receiver is evaluated for a specific downlink-limited satellite channel. Because of the bank of matched filters, the MLSD receiver may be high in complexity. Consequently, the probability of error performance of a more practical

  3. Evaluation of multiple-channel OFDM based airborne ultrasonic communications.

    Science.gov (United States)

    Jiang, Wentao; Wright, William M D

    2016-09-01

    Orthogonal frequency division multiplexing (OFDM) modulation has been extensively used in both wired and wireless communication systems. The use of OFDM technology allows very high spectral efficiency data transmission without using complex equalizers to correct the effect of a frequency-selective channel. This work investigated OFDM methods in an airborne ultrasonic communication system, using commercially available capacitive ultrasonic transducers operating at 50kHz to transmit information through the air. Conventional modulation schemes such as binary phase shift keying (BPSK) and quadrature amplitude modulation (QAM) were used to modulate sub-carrier signals, and the performances were evaluated in an indoor laboratory environment. Line-of-sight (LOS) transmission range up to 11m with no measurable errors was achieved using BPSK at a data rate of 45kb/s and a spectral efficiency of 1b/s/Hz. By implementing a higher order modulation scheme (16-QAM), the system data transfer rate was increased to 180kb/s with a spectral efficiency of 4b/s/Hz at attainable transmission distances up to 6m. Diffraction effects were incorporated into a model of the ultrasonic channel that also accounted for beam spread and attenuation in air. The simulations were a good match to the measured signals and non-LOS signals could be demodulated successfully. The effects of multipath interference were also studied in this work. By adding cyclic prefix (CP) to the OFDM symbols, the bit error rate (BER) performance was significantly improved in a multipath environment. Copyright © 2016 Elsevier B.V. All rights reserved.

  4. Statistical simulation of information transfer through non-line-of-sight atmospheric optical communication channels

    Science.gov (United States)

    Tarasenkov, M. V.; Belov, V. V.; Poznakharev, E. S.

    2017-11-01

    Impulse response of non-line-of-sight atmospheric communication channels at wavelengths of 0.3, 0.5, and 0.9 μm are compared for the case in which the optical axes of the receiver and laser radiation lie in the plane perpendicular to the Earth's surface. The most efficient communication channel depending on the base distance is determined. For a wavelength of 0.5 μm and a concrete variant of the transceiving part of the communication system, the limiting communication range and the limiting repetition frequency of pulses that can be transmitted through the communication channel are estimated.

  5. The Time Division Multi-Channel Communication Model and the Correlative Protocol Based on Quantum Time Division Multi-Channel Communication

    International Nuclear Information System (INIS)

    Liu Xiao-Hui; Pei Chang-Xing; Nie Min

    2010-01-01

    Based on the classical time division multi-channel communication theory, we present a scheme of quantum time-division multi-channel communication (QTDMC). Moreover, the model of quantum time division switch (QTDS) and correlative protocol of QTDMC are proposed. The quantum bit error rate (QBER) is analyzed and the QBER simulation test is performed. The scheme shows that the QTDS can carry out multi-user communication through quantum channel, the QBER can also reach the reliability requirement of communication, and the protocol of QTDMC has high practicability and transplantable. The scheme of QTDS may play an important role in the establishment of quantum communication in a large scale in the future. (general)

  6. Simulation of an Underwater Acoustic Communication Channel Characterized by Wind-Generated Surface Waves and Bubbles

    NARCIS (Netherlands)

    Dol, H.S.; Colin, M.E.G.D.; Ainslie, M.A.; Walree, P.A. van; Janmaat, J.

    2012-01-01

    Sea surface scattering by wind-generated waves and bubbles is regarded to be the main non-platform related cause of the time variability of shallow acoustic communication channels. Simulations for predicting the quality of acoustic communication links in such channels thus require adequate modeling

  7. Stress wave communication in concrete: I. Characterization of a smart aggregate based concrete channel

    International Nuclear Information System (INIS)

    Siu, Sam; Wu, Wenhao; Zhi Ding; Ji, Qing; Song, Gangbing

    2014-01-01

    In this paper, we explore the characteristics of a concrete block as a communication medium with piezoelectric transducers. Lead zirconate titanate (PZT) is a piezoceramic material used in smart materials intended for structural health monitoring (SHM). Additionally, a PZT based smart aggregate (SA) is capable of implementing stress wave communications which is utilized for investigating the properties of an SA based concrete channel. Our experiments characterize single-input single-output and multiple-input multiple-output (MIMO) concrete channels in order to determine the potential capacity limits of SAs for stress wave communication. We first provide estimates and validate the concrete channel response. Followed by a theoretical upper bound for data rate capacity of our two channels, demonstrating a near-twofold increase in channel capacity by utilizing multiple transceivers to form an MIMO system. Our channel modeling techniques and results are also helpful to researchers using SAs with regards to SHM, energy harvesting and stress wave communications. (paper)

  8. Efficient Weibull channel model for salinity induced turbulent underwater wireless optical communications

    KAUST Repository

    Oubei, Hassan M.

    2017-12-13

    Recent advances in underwater wireless optical communications necessitate a better understanding of the underwater channel. We propose the Weibull model to characterize the fading of salinity induced turbulent underwater wireless optical channels. The model shows an excellent agreement with the measured data under all channel conditions.

  9. The Emotiv EPOC interface paradigm in Human-Computer Interaction

    OpenAIRE

    Ancău Dorina; Roman Nicolae-Marius; Ancău Mircea

    2017-01-01

    Numerous studies have suggested the use of decoded error potentials in the brain to improve human-computer communication. Together with state-of-the-art scientific equipment, experiments have also tested instruments with more limited performance for the time being, such as Emotiv EPOC. This study presents a review of these trials and a summary of the results obtained. However, the level of these results indicates a promising prospect for using this headset as a human-computer interface for er...

  10. Design Considerations for Multi-Channel Picture Communication Networks

    OpenAIRE

    Scheibe, Paul O.

    1983-01-01

    Design of networks intended for communication of digitally-encoded pictures involves considerations different from those used in the design of text or voice communication networks. This paper provides an overview of the elements useful in the design of picture communication networks by relation and contrast with other communication networks. Particular emphasis is given to picture communication systems useful in medical applications.

  11. On the Secrecy Capacity of MISO Visible Light Communication Channels

    KAUST Repository

    Arfaoui, Mohamed Amine

    2017-02-07

    We study the secrecy capacity of the multiple- input single-output (MISO) Gaussian wiretap visible light communication (VLC) channel. We study a typical VLC scenario with one transmitter, one legitimate receiver, and one eavesdropper. Specifically, we compute the achievable secrecy rate for various input signaling distributions, including the truncated generalized normal (TGN) and uniform distributions. The transmitter is equipped with multiple light sources, while the legitimate and unauthorized receivers are each equipped with a single photodetector. We analyze the achievable secrecy rates via transmit beamforming and artificial noise. In addition, both zero-forcing beamforming and robust beamforming are considered. In the former case, the location of the eavesdropper is assumed to be known, whereas in the latter case, the location of the eavesdropper is unknown. Our numerical results show that the secrecy rate achieved by the TGN distribution is significantly improved as compared to those achieved by the truncated Gaussian and uniform distributions, for both zero-forcing beamforming and robust beamforming. We also derive an upper bound on the achievable secrecy capacity that we used to assess the closeness of the achievable secrecy rates to the derived bound.

  12. Particle Filtering Equalization Method for a Satellite Communication Channel

    Directory of Open Access Journals (Sweden)

    Amblard Pierre-Olivier

    2004-01-01

    Full Text Available We propose the use of particle filtering techniques and Monte Carlo methods to tackle the in-line and blind equalization of a satellite communication channel. The main difficulties encountered are the nonlinear distortions caused by the amplifier stage in the satellite. Several processing methods manage to take into account these nonlinearities but they require the knowledge of a training input sequence for updating the equalizer parameters. Blind equalization methods also exist but they require a Volterra modelization of the system which is not suited for equalization purpose for the present model. The aim of the method proposed in the paper is also to blindly restore the emitted message. To reach this goal, a Bayesian point of view is adopted. Prior knowledge of the emitted symbols and of the nonlinear amplification model, as well as the information available from the received signal, is jointly used by considering the posterior distribution of the input sequence. Such a probability distribution is very difficult to study and thus motivates the implementation of Monte Carlo simulation methods. The presentation of the equalization method is cut into two parts. The first part solves the problem for a simplified model, focusing on the nonlinearities of the model. The second part deals with the complete model, using sampling approaches previously developed. The algorithms are illustrated and their performance is evaluated using bit error rate versus signal-to-noise ratio curves.

  13. Nonverbal channel use in communication of emotion: how may depend on why.

    Science.gov (United States)

    App, Betsy; McIntosh, Daniel N; Reed, Catherine L; Hertenstein, Matthew J

    2011-06-01

    This study investigated the hypothesis that different emotions are most effectively conveyed through specific, nonverbal channels of communication: body, face, and touch. Experiment 1 assessed the production of emotion displays. Participants generated nonverbal displays of 11 emotions, with and without channel restrictions. For both actual production and stated preferences, participants favored the body for embarrassment, guilt, pride, and shame; the face for anger, disgust, fear, happiness, and sadness; and touch for love and sympathy. When restricted to a single channel, participants were most confident about their communication when production was limited to the emotion's preferred channel. Experiment 2 examined the reception or identification of emotion displays. Participants viewed videos of emotions communicated in unrestricted and restricted conditions and identified the communicated emotions. Emotion identification in restricted conditions was most accurate when participants viewed emotions displayed via the emotion's preferred channel. This study provides converging evidence that some emotions are communicated predominantly through different nonverbal channels. Further analysis of these channel-emotion correspondences suggests that the social function of an emotion predicts its primary channel: The body channel promotes social-status emotions, the face channel supports survival emotions, and touch supports intimate emotions.

  14. Passing crisis and emergency risk communications: the effects of communication channel, information type, and repetition.

    Science.gov (United States)

    Edworthy, Judy; Hellier, Elizabeth; Newbold, Lex; Titchener, Kirsteen

    2015-05-01

    Three experiments explore several factors which influence information transmission when warning messages are passed from person to person. In Experiment 1, messages were passed down chains of participants using five different modes of communication. Written communication channels resulted in more accurate message transmission than verbal. In addition, some elements of the message endured further down the chain than others. Experiment 2 largely replicated these effects and also demonstrated that simple repetition of a message eliminated differences between written and spoken communication. In a final field experiment, chains of participants passed information however they wanted to, with the proviso that half of the chains could not use telephones. Here, the lack of ability to use a telephone did not affect accuracy, but did slow down the speed of transmission from the recipient of the message to the last person in the chain. Implications of the findings for crisis and emergency risk communication are discussed. Copyright © 2015 Elsevier Ltd and The Ergonomics Society. All rights reserved.

  15. Modeling and characterization of different channels based on human body communication.

    Science.gov (United States)

    Jingzhen Li; Zedong Nie; Yuhang Liu; Lei Wang

    2017-07-01

    Human body communication (HBC), which uses the human body as a transmission medium for electrical signals, provides a prospective communication solution for body sensor networks (BSNs). In this paper, an inhomogeneous model which includes the tissue layers of skin, fat, and muscle is proposed to study the propagation characteristics of different HBC channels. Specifically, the HBC channels, namely, the on-body to on-body (OB-OB)channel, on-body to in-body (OB-IB) channel, in-body to on-body (IB-OB) channel, and in-body to in-body (IB-IB)channel, are studied over different frequencies (from 1MHz to 100MHz) through numerical simulations with finite-difference time-domain (FDTD) method. The results show that the gain of OB-IB channel and IB-OB channel is almost the same. The gain of IB-IB channel is greater than other channels in the frequency range 1MHz to 70MHz. In addition, the gain of all channels is associated with the channel length and communication frequency. The simulations are verified by experimental measurements in a porcine tissue sample. The results show that the simulations are in agreement with the measurements.

  16. Digital portfolio for learning: A new communication channel for education

    Directory of Open Access Journals (Sweden)

    Judit Coromina

    2011-04-01

    Full Text Available Purpose: The Catalonian Government has the intention of introducing the digital portfolio before 2017, an initiative related to new approaches for learning. Taking in consideration the increasing interest for digital portfolio as a new communication channel for education, the article aims are: on the one hand to describe how the digital portfolio works and on the other hand, to identify a list of criteria that should be useful for educative centers to select the best application to create the digital portfolio according to their needs.Design/methodology/approach: Firstly, a theoretical framework for portfolio functioning is described. After, applications to support the digital portfolio are classified. Next, a requirement analysis on an ideal application to support the portfolio is made, according to those phases for the portfolio creation identified in the theoretical framework. Lastly, a list of criteria is established to select the application for creating the digital portfolio.Findings and Originality/value: The article contributes to structure the portfolio creation process in some stages and phases in a wider way that it is described in the literature. In addition, a list of criteria is defined to help educative centers to select the application for managing the portfolio that fits better with their objectives. These criteria have been obtained with an exhaustive methodology.Research limitations/implications: In order to put in practice the identified criteria it is proposed to complete the multi-criteria decision model in a new study. It should include processes to weigh criteria and define normalizations. Afterwards it would be able to analyze the value of the model studying the satisfaction for using it by a sample of educative centers.Practical implications: The list of criteria identified should facilitate the selection of the more adequate application to create the learning portfolio to the educative centers, according to their

  17. Minimal mobile human computer interaction

    NARCIS (Netherlands)

    el Ali, A.

    2013-01-01

    In the last 20 years, the widespread adoption of personal, mobile computing devices in everyday life, has allowed entry into a new technological era in Human Computer Interaction (HCI). The constant change of the physical and social context in a user's situation made possible by the portability of

  18. Artifical Intelligence for Human Computing

    NARCIS (Netherlands)

    Huang, Th.S.; Nijholt, Antinus; Pantic, Maja; Pentland, A.; Unknown, [Unknown

    2007-01-01

    This book constitutes the thoroughly refereed post-proceedings of two events discussing AI for Human Computing: one Special Session during the Eighth International ACM Conference on Multimodal Interfaces (ICMI 2006), held in Banff, Canada, in November 2006, and a Workshop organized in conjunction

  19. Pilot-based parametric channel estimation algorithm for DCO-OFDM-based visual light communications

    Science.gov (United States)

    Qian, Xuewen; Deng, Honggui; He, Hailang

    2017-10-01

    Due to wide modulation bandwidth in optical communication, multipath channels may be non-sparse and deteriorate communication performance heavily. Traditional compressive sensing-based channel estimation algorithm cannot be employed in this kind of situation. In this paper, we propose a practical parametric channel estimation algorithm for orthogonal frequency division multiplexing (OFDM)-based visual light communication (VLC) systems based on modified zero correlation code (ZCC) pair that has the impulse-like correlation property. Simulation results show that the proposed algorithm achieves better performances than existing least squares (LS)-based algorithm in both bit error ratio (BER) and frequency response estimation.

  20. Communication and Student Unrest: A Report to the President of the University of New Mexico; Part I: Student-Administration Channels, Student Faculty Channels.

    Science.gov (United States)

    Goldhaber, Gerald M.

    This initial segment of a three-part study (Communication and Student Unrest) is an examination of the various communication channels--informal and formal, vertical and horizontal--which exist for student-administration and student-faculty interaction. Student-administration and student-faculty communication channels are discussed separately, and…

  1. Cyclic Communication and the Inseparability of MIMO Multi-way Relay Channels

    KAUST Repository

    Chaaban, Anas; Sezgin, Aydin

    2015-01-01

    The K-user MIMO multi-way relay channel (Ychannel) consisting of K users with M antennas each and a common relay node with N antennas is studied in this paper. Each user wants to exchange messages with all the other users via the relay. A transmission strategy is proposed for this channel. The proposed strategy is based on two steps: channel diagonalization and cyclic communication. The channel diagonalization is applied by using zero-forcing beam-forming. After channel diagonalization, the channel is decomposed into parallel sub-channels. Cyclic communication is then applied, where signal-space alignment for network-coding is used over each sub-channel. The proposed strategy achieves the optimal DoF region of the channel if N M. To prove this, a new degrees-of-freedom outer bound is derived. As a by-product, we conclude that the MIMO Y-channel is not separable, i.e., independent coding on separate sub-channels is not enough, and one has to code jointly over several sub-channels.

  2. Cyclic Communication and the Inseparability of MIMO Multi-way Relay Channels

    KAUST Repository

    Chaaban, Anas

    2015-10-27

    The K-user MIMO multi-way relay channel (Ychannel) consisting of K users with M antennas each and a common relay node with N antennas is studied in this paper. Each user wants to exchange messages with all the other users via the relay. A transmission strategy is proposed for this channel. The proposed strategy is based on two steps: channel diagonalization and cyclic communication. The channel diagonalization is applied by using zero-forcing beam-forming. After channel diagonalization, the channel is decomposed into parallel sub-channels. Cyclic communication is then applied, where signal-space alignment for network-coding is used over each sub-channel. The proposed strategy achieves the optimal DoF region of the channel if N M. To prove this, a new degrees-of-freedom outer bound is derived. As a by-product, we conclude that the MIMO Y-channel is not separable, i.e., independent coding on separate sub-channels is not enough, and one has to code jointly over several sub-channels.

  3. Simple statistical channel model for weak temperature-induced turbulence in underwater wireless optical communication systems

    KAUST Repository

    Oubei, Hassan M.

    2017-06-16

    In this Letter, we use laser beam intensity fluctuation measurements to model and describe the statistical properties of weak temperature-induced turbulence in underwater wireless optical communication (UWOC) channels. UWOC channels with temperature gradients are modeled by the generalized gamma distribution (GGD) with an excellent goodness of fit to the measured data under all channel conditions. Meanwhile, thermally uniform channels are perfectly described by the simple gamma distribution which is a special case of GGD. To the best of our knowledge, this is the first model that comprehensively describes both thermally uniform and gradient-based UWOC channels.

  4. Integrated multi-channel vehicle-vehicle and vehicle-roadside communications for ITS

    Science.gov (United States)

    2008-12-01

    This research describes a medium access control (MAC) protocol to Enable multi-channel operation for dedicated short-range communication (DSRC). In particular, we focus on the challenge of supporting potentially high-bandwidth commercial or infotainm...

  5. Evaluation of coherence interference in optical wireless communication through multiscattering channels.

    Science.gov (United States)

    Kedar, Debbie; Arnon, Shlomi

    2006-05-10

    Optical wireless communication has been the subject of much research in recent years because of the increasing interest in laser satellite-ground links and urban optical wireless communication. The major sources of performance degradation have been identified as the spatial, angular, and temporal spread of the propagating beam when the propagation channel is multiscattering, resulting in reduced power reception and intersignal interference, as well as turbulence-induced scintillations and noise due to receiver circuitry and background illumination. However, coherence effects due to multipath interference caused by a scattering propagation channel do not appear to have been treated in detail in the scientific literature. We attempt a theoretical analysis of coherence interference in optical wireless communication through scattering channels and try to quantify the resultant performance degradation for different media. We conclude that coherence interference is discernible in optical wireless communication through scattering channels and is highly dependent on the microscopic nature of the propagation medium.

  6. Optimal coding-decoding for systems controlled via a communication channel

    Science.gov (United States)

    Yi-wei, Feng; Guo, Ge

    2013-12-01

    In this article, we study the problem of controlling plants over a signal-to-noise ratio (SNR) constrained communication channel. Different from previous research, this article emphasises the importance of the actual channel model and coder/decoder in the study of network performance. Our major objectives include coder/decoder design for an additive white Gaussian noise (AWGN) channel with both standard network configuration and Youla parameter network architecture. We find that the optimal coder and decoder can be realised for different network configuration. The results are useful in determining the minimum channel capacity needed in order to stabilise plants over communication channels. The coder/decoder obtained can be used to analyse the effect of uncertainty on the channel capacity. An illustrative example is provided to show the effectiveness of the results.

  7. Faithful qubit transmission in a quantum communication network with heterogeneous channels

    Science.gov (United States)

    Chen, Na; Zhang, Lin Xi; Pei, Chang Xing

    2018-04-01

    Quantum communication networks enable long-distance qubit transmission and distributed quantum computation. In this paper, a quantum communication network with heterogeneous quantum channels is constructed. A faithful qubit transmission scheme is presented. Detailed calculations and performance analyses show that even in a low-quality quantum channel with serious decoherence, only modest number of locally prepared target qubits are required to achieve near-deterministic qubit transmission.

  8. Improving B2B communication by utilizing digital marketing channels : a case study of REALPAD

    OpenAIRE

    Vuong Yen, Trang; Do, Thu

    2016-01-01

    REALPAD is a fast developing company that offers CRM software for residential real estate developers. The company is planning to expand its sales to new parts of the world and therefore has a need for more effective communication channels for the company to reach more prospects in the international market. The main objective of this thesis project was to find out how to improve REALPAD’s communication with potential and existing customers by using various digital marketing channels. In or...

  9. A review on channel models in free space optical communication systems

    Science.gov (United States)

    Anbarasi, K.; Hemanth, C.; Sangeetha, R. G.

    2017-12-01

    Free Space Optical communication (FSO) is a wireless communication technology which uses light to transmit the data in free space. FSO has advantages like unlicensed spectrum and higher bandwidth. In this paper FSO system merits and demerits, challenges in FSO, and various channel models are discussed. To mitigate the turbulence in FSO the mitigation techniques like relaying, diversity schemes and adopting different modulation techniques used in different channels are discussed and its performance comparison is given.

  10. A Study on the Inter-Channel Communication Independence for SMART I and C System

    International Nuclear Information System (INIS)

    Jeong, Kwang Il; Keum, Jong Yong; Park, Je Yun

    2009-01-01

    In nuclear power plants (NPP) the greatest concern is to ensure the safety goal, so it is designed with a protection conception using diversity and redundancy methods. Usually the I and C (Instrumentation and Control) system of NPP is composed of four channels to enhance the performance of the safety functions and performs the monitoring and control functions. In these redundant structures, the most important thing is that a malfunction in one channel cannot affect the safety functions of the redundant channels. The communication network of the digital I and C system is playing a role in intra-channel communication and inter-channel communication in four-channel I and C structure. Recent licensee experience indicates that companies planning to use the interchannel communication must perform a detailed analysis of all credible failure modes. In this paper, we propose some evaluation criteria to evaluate the inter-channel communication independence of SMART I and C system and preliminary design for mitigating methodologies of each credible failure

  11. Underwater wireless optical communications: From system-level demonstrations to channel modelling

    KAUST Repository

    Oubei, Hassan M.

    2018-01-09

    In this paper, we discuss about recent experimental advances in underwater wireless optical communications (UWOC) over various underwater channel water types using different modulation schemes as well as modelling and describing the statistical properties of turbulence-induced fading in underwater wireless optical channels using laser beam intensity fluctuations measurements.

  12. INVESTIGATION OF ADS-B MESSAGES TRAFFIC VIA SATELLITE COMMUNICATION CHANNEL

    OpenAIRE

    Volodymyr Kharchenko; Wang Bo; Andrii Grekhov; Marina Kovalenko

    2014-01-01

    For modelling of ADS-B messages transmition with the help of low-orbit satellite complex Іrіdіumdifferent models of communication channel "Aircraft-to-Satellites-to-Ground Stations" were built using NetCrackerProfessіonal 4.1 software. Influence of aircraft and satellites amount on average link utilization and message travellingtime was studied for telecommunication channels with intersatellite link and bent-pipe architecture. The effect ofcommunication channel "saturation" during simultaneou...

  13. Frequency domain based LS channel estimation in OFDM based Power line communications

    OpenAIRE

    Bogdanović, Mario

    2015-01-01

    This paper is focused on low voltage power line communication (PLC) realization with an emphasis on channel estimation techniques. The Orthogonal Frequency Division Multiplexing (OFDM) scheme is preferred technology in PLC systems because of its effective combat with frequency selective fading properties of PLC channel. As the channel estimation is one of the crucial problems in OFDM based PLC system because of a problematic area of PLC signal attenuation and interference, the improved LS est...

  14. Measurement-based Channel Characterization for 5G Wireless Communications on Campus Scenario

    DEFF Research Database (Denmark)

    Mi, Yang; He, Ruisi; Ai, Bo

    2017-01-01

    The fifth generation (5G) communication has been a hotspot of research in recent years, and both research institutions and industrial enterprises put a lot of interests for 5G communication at some new frequency bands. In this paper, we investigate the radio channels of 5G communications below 6...... GHz according to the requirements and scenarios of 5G communication. Channel measurements were conducted on campus of Beijing Jiaotong University, China at two key optional frequency bands below 6 GHz. By using the measured data, we analyzed key channel parameters at 460MHz and 3.5GHz, such as power...... delay profile, path loss exponent, shadow fading, and delay spread. The results are helpful for the 5G communication system design....

  15. Moderate Deviation Analysis for Classical Communication over Quantum Channels

    Science.gov (United States)

    Chubb, Christopher T.; Tan, Vincent Y. F.; Tomamichel, Marco

    2017-11-01

    We analyse families of codes for classical data transmission over quantum channels that have both a vanishing probability of error and a code rate approaching capacity as the code length increases. To characterise the fundamental tradeoff between decoding error, code rate and code length for such codes we introduce a quantum generalisation of the moderate deviation analysis proposed by Altŭg and Wagner as well as Polyanskiy and Verdú. We derive such a tradeoff for classical-quantum (as well as image-additive) channels in terms of the channel capacity and the channel dispersion, giving further evidence that the latter quantity characterises the necessary backoff from capacity when transmitting finite blocks of classical data. To derive these results we also study asymmetric binary quantum hypothesis testing in the moderate deviations regime. Due to the central importance of the latter task, we expect that our techniques will find further applications in the analysis of other quantum information processing tasks.

  16. An FPGA-Based Adaptable 200 MHz Bandwidth Channel Sounder for Wireless Communication Channel Characterisation

    Directory of Open Access Journals (Sweden)

    David L. Ndzi

    2011-01-01

    Full Text Available This paper describes the development of a fast adaptable FPGA-based wideband channel sounder with signal bandwidths of up to 200 MHz and channel sampling rates up to 5.4 kHz. The application of FPGA allows the user to vary the number of real-time channel response averages, channel sampling interval, and duration of measurement. The waveform, bandwidth, and frequency resolution of the sounder can be adapted for any channel under investigation. The design approach and technology used has led to a reduction in size and weight by more than 60%. This makes the sounder ideal for mobile time-variant wireless communication channels studies. Averaging allows processing gains of up to 30 dB to be achieved for measurement in weak signal conditions. The technique applied also improves reliability, reduces power consumption, and has shifted sounder design complexity from hardware to software. Test results show that the sounder can detect very small-scale variations in channels.

  17. Characterizing Social Networks and Communication Channels in a Web-Based Peer Support Intervention.

    Science.gov (United States)

    Owen, Jason E; Curran, Michaela; Bantum, Erin O'Carroll; Hanneman, Robert

    2016-06-01

    Web and mobile (mHealth) interventions have promise for improving health outcomes, but engagement and attrition may be reducing effect sizes. Because social networks can improve engagement, which is a key mechanism of action, understanding the structure and potential impact of social networks could be key to improving mHealth effects. This study (a) evaluates social network characteristics of four distinct communication channels (discussion board, chat, e-mail, and blog) in a large social networking intervention, (b) predicts membership in online communities, and (c) evaluates whether community membership impacts engagement. Participants were 299 cancer survivors with significant distress using the 12-week health-space.net intervention. Social networking attributes (e.g., density and clustering) were identified separately for each type of network communication (i.e., discussion board, blog, web mail, and chat). Each channel demonstrated high levels of clustering, and being a community member in one communication channel was associated with being in the same community in each of the other channels (φ = 0.56-0.89, ps < 0.05). Predictors of community membership differed across communication channels, suggesting that each channel reached distinct types of users. Finally, membership in a discussion board, chat, or blog community was strongly associated with time spent engaging with coping skills exercises (Ds = 1.08-1.84, ps < 0.001) and total time of intervention (Ds = 1.13-1.80, ps < 0.001). mHealth interventions that offer multiple channels for communication allow participants to expand the number of individuals with whom they are communicating, create opportunities for communicating with different individuals in distinct channels, and likely enhance overall engagement.

  18. Characterizing Social Networks and Communication Channels in a Web-Based Peer Support Intervention

    Science.gov (United States)

    Curran, Michaela; Bantum, Erin O'Carroll; Hanneman, Robert

    2016-01-01

    Abstract Web and mobile (mHealth) interventions have promise for improving health outcomes, but engagement and attrition may be reducing effect sizes. Because social networks can improve engagement, which is a key mechanism of action, understanding the structure and potential impact of social networks could be key to improving mHealth effects. This study (a) evaluates social network characteristics of four distinct communication channels (discussion board, chat, e-mail, and blog) in a large social networking intervention, (b) predicts membership in online communities, and (c) evaluates whether community membership impacts engagement. Participants were 299 cancer survivors with significant distress using the 12-week health-space.net intervention. Social networking attributes (e.g., density and clustering) were identified separately for each type of network communication (i.e., discussion board, blog, web mail, and chat). Each channel demonstrated high levels of clustering, and being a community member in one communication channel was associated with being in the same community in each of the other channels (φ = 0.56–0.89, ps < 0.05). Predictors of community membership differed across communication channels, suggesting that each channel reached distinct types of users. Finally, membership in a discussion board, chat, or blog community was strongly associated with time spent engaging with coping skills exercises (Ds = 1.08–1.84, ps < 0.001) and total time of intervention (Ds = 1.13–1.80, ps < 0.001). mHealth interventions that offer multiple channels for communication allow participants to expand the number of individuals with whom they are communicating, create opportunities for communicating with different individuals in distinct channels, and likely enhance overall engagement. PMID:27327066

  19. Phase-Type Models of Channel-Holding Times in Cellular Communication Systems

    DEFF Research Database (Denmark)

    Christensen, Thomas Kaare; Nielsen, Bo Friis; Iversen, Villy Bæk

    2004-01-01

    In this paper, we derive the distribution of the channel-holding time when both cell-residence and call-holding times are phase-type distributed. Furthermore, the distribution of the number of handovers, the conditional channel-holding time distributions, and the channel-holding time when cell re...... residence times are correlated are derived. All distributions are of phase type, making them very general and flexible. The channel-holding times are of importance in performance evaluation and simulation of cellular mobile communication systems.......In this paper, we derive the distribution of the channel-holding time when both cell-residence and call-holding times are phase-type distributed. Furthermore, the distribution of the number of handovers, the conditional channel-holding time distributions, and the channel-holding time when cell...

  20. Information-guided communications in MIMO systems with channel state impairments

    KAUST Repository

    Yang, Yuli

    2013-06-20

    Information-guided channel hopping (IGCH) is a promising technique for high-data-rate communications using multiple antennas for information mapping at the transmitter and optional antenna diversity at the receiver. Compared with some popular multi-antenna techniques, the advantage of this scheme is proven in ideal channel conditions, where the channel is spatially white and the perfect channel state information is assumed available at the receiver. The main objective of this paper is to present an information theoretical study on IGCH in realistic propagation environments with channel degeneracy due to spatial correlation and keyhole phenomena as well as imperfect channel estimation. It is proven that good performance promised by IGCH can be achieved in a variety of non-ideal channel conditions. Moreover, the analysis in this paper provides a convenient tool for the corresponding system design in practical operating environments. © 2013 John Wiley & Sons, Ltd.

  1. Information-guided communications in MIMO systems with channel state impairments

    KAUST Repository

    Yang, Yuli; Aï ssa, Sonia

    2013-01-01

    Information-guided channel hopping (IGCH) is a promising technique for high-data-rate communications using multiple antennas for information mapping at the transmitter and optional antenna diversity at the receiver. Compared with some popular multi-antenna techniques, the advantage of this scheme is proven in ideal channel conditions, where the channel is spatially white and the perfect channel state information is assumed available at the receiver. The main objective of this paper is to present an information theoretical study on IGCH in realistic propagation environments with channel degeneracy due to spatial correlation and keyhole phenomena as well as imperfect channel estimation. It is proven that good performance promised by IGCH can be achieved in a variety of non-ideal channel conditions. Moreover, the analysis in this paper provides a convenient tool for the corresponding system design in practical operating environments. © 2013 John Wiley & Sons, Ltd.

  2. Creating Feedback Channels With Optical Communications For Information Operations (IO)

    Science.gov (United States)

    2016-06-01

    amphibious operations. Optical communications technologies, direct marketing principles , and current IO shortfalls are explored to determine whether...technology. First, these concepts are applied to show covert amphibious operations. Optical communications technologies, direct marketing principles , and...power, as per Appendix A. A major portion of the marketing campaign comes in the form of advertising. The correlating principles of advertising in

  3. Wireless Channel Modeling Perspectives for Ultra-Reliable Communications

    DEFF Research Database (Denmark)

    Eggers, Patrick Claus F.; Popovski, Petar

    2018-01-01

    Ultra-Reliable Communication (URC) is one of the distinctive features of the upcoming 5G wireless communication. The level of reliability, going down to packet error rates (PER) of $10^{-9}$, should be sufficiently convincing in order to remove cables in an industrial setting or provide remote co...

  4. Communication Channels as Implementation Determinants of Performance Management Framework in Kenya

    Science.gov (United States)

    Sang, Jane

    2016-01-01

    The purpose of this study to assess communication channels as implementation determinants of performance management framework In Kenya at Moi Teaching and Referral Hospital (MTRH). The communication theory was used to inform the study. This study adopted an explanatory design. The target sampled 510 respondents through simple random and stratified…

  5. Digital Channels in Teacher-Parent Communication: The Case of Estonia

    Science.gov (United States)

    Palts, Karmen; Kalmus, Veronika

    2015-01-01

    The aim of this paper is to analyse the attitudes of Estonian primary school teachers and parents regarding the role of mutual digital communication in socialising the child and in the child's academic progress, their communication channel preferences, and related experiences and opinions. The main starting points are Bronfenbrenner's (1979)…

  6. Compressive Sensing Based Bayesian Sparse Channel Estimation for OFDM Communication Systems: High Performance and Low Complexity

    Science.gov (United States)

    Xu, Li; Shan, Lin; Adachi, Fumiyuki

    2014-01-01

    In orthogonal frequency division modulation (OFDM) communication systems, channel state information (CSI) is required at receiver due to the fact that frequency-selective fading channel leads to disgusting intersymbol interference (ISI) over data transmission. Broadband channel model is often described by very few dominant channel taps and they can be probed by compressive sensing based sparse channel estimation (SCE) methods, for example, orthogonal matching pursuit algorithm, which can take the advantage of sparse structure effectively in the channel as for prior information. However, these developed methods are vulnerable to both noise interference and column coherence of training signal matrix. In other words, the primary objective of these conventional methods is to catch the dominant channel taps without a report of posterior channel uncertainty. To improve the estimation performance, we proposed a compressive sensing based Bayesian sparse channel estimation (BSCE) method which cannot only exploit the channel sparsity but also mitigate the unexpected channel uncertainty without scarifying any computational complexity. The proposed method can reveal potential ambiguity among multiple channel estimators that are ambiguous due to observation noise or correlation interference among columns in the training matrix. Computer simulations show that proposed method can improve the estimation performance when comparing with conventional SCE methods. PMID:24983012

  7. Numerical Simulation of Dual-Channel Communication of Column Plasma Antenna Excited by a Surface Wave

    International Nuclear Information System (INIS)

    Duanmu Gang; Zhao Changming; Liang Chao; Xu Yuemin

    2014-01-01

    This paper focuses on the application of plasma as wireless antenna. In order to reveal the radiation characteristics of column plasma antenna, we chose the finite-difference time-domain (FDTD) numerical analysis method to simulate radiation impedance and efficiencies of each channel for a few sets of plasma densities and plasma collision frequencies. Simulation results demonstrate that a plasma antenna shares similar characteristics with a metallic antenna in radiation impedance and efficiency of each channel when an appropriate setting is adopted. Unlike a metallic antenna, a plasma antenna is capable of realizing such functions as dynamic reconfiguration, digital control and dual-channel communication. Thus it is possible to carry out dual-channel communication by plasma antenna, indicating a new path for modern intelligent communication. (plasma technology)

  8. Science communication on YouTube: Factors that affect channel and video popularity.

    Science.gov (United States)

    Welbourne, Dustin J; Grant, Will J

    2016-08-01

    YouTube has become one of the largest websites on the Internet. Among its many genres, both professional and amateur science communicators compete for audience attention. This article provides the first overview of science communication on YouTube and examines content factors that affect the popularity of science communication videos on the site. A content analysis of 390 videos from 39 YouTube channels was conducted. Although professionally generated content is superior in number, user-generated content was significantly more popular. Furthermore, videos that had consistent science communicators were more popular than those without a regular communicator. This study represents an important first step to understand content factors, which increases the channel and video popularity of science communication on YouTube. © The Author(s) 2015.

  9. Guest Editorial Special Issue on Human Computing

    NARCIS (Netherlands)

    Pantic, Maja; Santos, E.; Pentland, A.; Nijholt, Antinus

    2009-01-01

    The seven articles in this special issue focus on human computing. Most focus on two challenging issues in human computing, namely, machine analysis of human behavior in group interactions and context-sensitive modeling.

  10. Measurement and analysis of channel attenuation characteristics for an implantable galvanic coupling human-body communication.

    Science.gov (United States)

    Zhang, Shuang; Pun, Sio Hang; Mak, Peng Un; Qin, Yu-Ping; Liu, Yi-He; Vai, Mang I

    2016-11-14

    In this study, an experiment was designed to verify the low power consumption of galvanic coupling human-body communication. A silver electrode (silver content: 99%) is placed in a pig leg and a sine wave signal with the power of 0 dBm is input. Compared with radio frequency communication and antenna transmission communication, attenuation is reduced by approximately 10 to 15 dB, so channel characteristics are highly improved.

  11. Integrated source and channel encoded digital communication system design study. [for space shuttles

    Science.gov (United States)

    Huth, G. K.

    1976-01-01

    The results of several studies Space Shuttle communication system are summarized. These tasks can be divided into the following categories: (1) phase multiplexing for two- and three-channel data transmission, (2) effects of phase noise on the performance of coherent communication links, (3) analysis of command system performance, (4) error correcting code tradeoffs, (5) signal detection and angular search procedure for the shuttle Ku-band communication system, and (6) false lock performance of Costas loop receivers.

  12. Discrete Input Signaling for MISO Visible Light Communication Channels

    KAUST Repository

    Arfaoui, Mohamed Amine; Rezki, Zouheir; Ghrayeb, Ali; Alouini, Mohamed-Slim

    2017-01-01

    In this paper, we study the achievable secrecy rate of visible light communication (VLC) links for discrete input distributions. We consider single user single eavesdropper multiple-input single-output (MISO) links. In addition, both beamforming

  13. Radio Channel Modelling for UAV Communication over Cellular Networks

    DEFF Research Database (Denmark)

    Amorim, Rafhael Medeiros de; Nguyen, Huan Cong; Mogensen, Preben Elgaard

    2017-01-01

    The main goal of this paper is to obtain models for path loss exponents and shadowing for the radio channel between airborne Unmanned Aerial Vehicles (UAVs) and cellular networks. In this pursuit, field measurements were conducted in live LTE networks at the 800 MHz frequency band, using a commer...

  14. Radio Channel Modelling for UAV Communication over Cellular Networks

    DEFF Research Database (Denmark)

    Amorim, Rafhael Medeiros de; Nguyen, Huan Cong; Mogensen, Preben Elgaard

    2017-01-01

    a commercial UAV. Our results show that path loss exponents decrease as the UAV moves up, approximating freespace propagation for horizontal ranges up to tens of kilometers at UAV heights around 100m. Our findings support the need of heightdependent parameters for describing the propagation channel for UAVs...

  15. Human computer interaction using hand gestures

    CERN Document Server

    Premaratne, Prashan

    2014-01-01

    Human computer interaction (HCI) plays a vital role in bridging the 'Digital Divide', bringing people closer to consumer electronics control in the 'lounge'. Keyboards and mouse or remotes do alienate old and new generations alike from control interfaces. Hand Gesture Recognition systems bring hope of connecting people with machines in a natural way. This will lead to consumers being able to use their hands naturally to communicate with any electronic equipment in their 'lounge.' This monograph will include the state of the art hand gesture recognition approaches and how they evolved from their inception. The author would also detail his research in this area for the past 8 years and how the future might turn out to be using HCI. This monograph will serve as a valuable guide for researchers (who would endeavour into) in the world of HCI.

  16. A Vertical Channel Model of Molecular Communication based on Alcohol Molecules

    Directory of Open Access Journals (Sweden)

    Pengfei Lu

    2016-05-01

    Full Text Available The study of Molecular Communication(MC is more and more prevalence, and channel model of MC plays an important role in the MC System. Since different propagation environment and modulation techniques produce different channel model, most of the research about MC are in horizontal direction,but in nature the communications between nano machines are in short range and some of the information transportation are in the vertical direction, such as transpiration of plants, biological pump in ocean, and blood transportation from heart to brain. Therefore, this paper we propose a vertical channel model which nano-machines communicate with each other in the vertical direction based on pure diffusion. We rst propose a vertical molecular communication model, we mainly considered the gravity as the factor, though the channel model is also affected by other main factors, such as the ow of the medium, the distance between the transmitter and the receiver, the delay or sensitivity of the transmitter and the receiver. Secondly, we set up a test-bed for this vertical channel model, in order to verify the difference between the theory result and the experiment data. At last, we use the data we get from the experiment and the non-linear least squares method to get the parameters to make our channel model more accurate.

  17. Mitigation Technique for Receiver Performance Variation of Multi-Color Channels in Visible Light Communication

    Directory of Open Access Journals (Sweden)

    Yeong Min Jang

    2011-06-01

    Full Text Available “Green” and energy-efficient wireless communication schemes have recently experienced rapid development and garnered much interest. One such scheme is visible light communication (VLC which is being touted as one of the next generation wireless communication systems. VLC allows communication using multi-color channels that provide high data rates and illumination simultaneously. Even though VLC has many advantageous features compared with RF technologies, including visibility, ubiquitousness, high speed, high security, harmlessness for the human body and freedom of RF interference, it suffers from some problems on the receiver side, one of them being photo sensitivity dissimilarity of the receiver. The photo sensitivity characteristics of a VLC receiver such as Si photo-detector depend on the wavelength variation. The performance of the VLC receiver is not uniform towards all channel colors, but it is desirable for receivers to have the same performance on each color channel. In this paper, we propose a mitigation technique for reducing the performance variation of the receiver on multi-color channels. We show received power, SNR, BER, output current, and outage probability in our simulation for different color channels. Simulation results show that, the proposed scheme can reduce the performance variation of the VLC receiver on multi-color channels.

  18. The Emotiv EPOC interface paradigm in Human-Computer Interaction

    Directory of Open Access Journals (Sweden)

    Ancău Dorina

    2017-01-01

    Full Text Available Numerous studies have suggested the use of decoded error potentials in the brain to improve human-computer communication. Together with state-of-the-art scientific equipment, experiments have also tested instruments with more limited performance for the time being, such as Emotiv EPOC. This study presents a review of these trials and a summary of the results obtained. However, the level of these results indicates a promising prospect for using this headset as a human-computer interface for error decoding.

  19. Integrated source and channel encoded digital communication system design study

    Science.gov (United States)

    Alem, W. K.; Huth, G. K.; Simon, M. K.

    1978-01-01

    The particular Ku-band carrier, PN despreading, and symbol synchronization strategies, which were selected for implementation in the Ku-band transponder aboard the orbiter, were assessed and evaluated from a systems performance viewpoint, verifying that system specifications were met. A study was performed of the design and implementation of tracking techniques which are suitable for incorporation into the Orbiter Ku-band communication system. Emphasis was placed on maximizing tracking accuracy and communication system flexibility while minimizing cost, weight, and system complexity of Orbiter and ground systems hardware. The payload communication study assessed the design and performance of the forward link and return link bent-pipe relay modes for attached and detached payloads. As part of this study, a design for a forward link bent-pipe was proposed which employs a residual carrier but which is tracked by the existing Costas loop.

  20. The Relationship between Marketing Strategy and Marketing Channels of Communication

    OpenAIRE

    Sayed Masud Sayedi; Hassan Soltani; Majid Keshavarz

    2014-01-01

    The overall objective of this study is to investigate the relationship between the expansion of marketing channels and marketing strategy is the first to examine the process of a questionnaire containing 19 questions was used as the existing standard. The research population, employees of manufacturing companies and trading company in Iran that their number is 1176 people. Sample size using the formula by including sampling error was estimated at 0.05 confidence level 0.95 times the number of...

  1. Experimental evaluation of multimodal human computer interface for tactical audio applications

    NARCIS (Netherlands)

    Obrenovic, Z.; Starcevic, D.; Jovanov, E.; Oy, S.

    2002-01-01

    Mission critical and information overwhelming applications require careful design of the human computer interface. Typical applications include night vision or low visibility mission navigation, guidance through a hostile territory, and flight navigation and orientation. Additional channels of

  2. An End-to-End Model of Plant Pheromone Channel for Long Range Molecular Communication.

    Science.gov (United States)

    Unluturk, Bige D; Akyildiz, Ian F

    2017-01-01

    A new track in molecular communication is using pheromones which can scale up the range of diffusion-based communication from μm meters to meters and enable new applications requiring long range. Pheromone communication is the emission of molecules in the air which trigger behavioral or physiological responses in receiving organisms. The objective of this paper is to introduce a new end-to-end model which incorporates pheromone behavior with communication theory for plants. The proposed model includes both the transmission and reception processes as well as the propagation channel. The transmission process is the emission of pheromones from the leaves of plants. The dispersion of pheromones by the flow of wind constitutes the propagation process. The reception process is the sensing of pheromones by the pheromone receptors of plants. The major difference of pheromone communication from other molecular communication techniques is the dispersion channel acting under the laws of turbulent diffusion. In this paper, the pheromone channel is modeled as a Gaussian puff, i.e., a cloud of pheromone released instantaneously from the source whose dispersion follows a Gaussian distribution. Numerical results on the performance of the overall end-to-end pheromone channel in terms of normalized gain and delay are provided.

  3. Ultra-fast secure communication with complex systems in classical channels (Conference Presentation)

    KAUST Repository

    Mazzone, Valerio

    2017-04-28

    Developing secure communications is a research area of growing interest. During the past years, several cryptographic schemes have been developed, with Quantum cryptography being a promising scheme due to the use of quantum effects, which make very difficult for an eavesdropper to intercept the communication. However, practical quantum key distribution methods have encountered several limitations; current experimental realizations, in fact, fail to scale up on long distances, as well as in providing unconditional security and speed comparable to classical optical communications channels. Here we propose a new, low cost and ultra-fast cryptographic system based on a fully classical optical channel. Our cryptographic scheme exploits the complex synchronization of two different random systems (one on the side of the sender and another on the side of the receiver) to realize a “physical” one paid system. The random medium is created by an optical chip fabricated through electron beam lithography on a Silicon On Insulator (SOI) substrate. We present experiments with ps lasers and commercial fibers, showing the ultrafast distribution of a random key between two users (Alice and Bob), with absolute no possibility for a passive/active eavesdropper to intercept the communication. Remarkably, this system enables the same security of quantum cryptography, but with the use of a classical communication channel. Our system exploits a unique synchronization that exists between two different random systems, and at such is extremely versatile and can enable safe communications among different users in standards telecommunications channels.

  4. Wireless Communication over Time-Varying Channels With Limited Feedback

    NARCIS (Netherlands)

    Simon, C.

    2011-01-01

    The number of deployed wireless communication systems has grown rapidly in the last years. Their popularity is mainly due to the effortlessness with which the systems can be deployed. Further, the new generation of wireless systems, e.g., 802.11n, starts to close the performance gap to their wired

  5. Basis expansion model for channel estimation in LTE-R communication system

    Directory of Open Access Journals (Sweden)

    Ling Deng

    2016-05-01

    Full Text Available This paper investigates fast time-varying channel estimation in LTE-R communication systems. The Basis Expansion Model (BEM is adopted to fit the fast time-varying channel in a high-speed railway communication scenario. The channel impulse response is modeled as the sum of basis functions multiplied by different coefficients. The optimal coefficients are obtained by theoretical analysis. Simulation results show that a Generalized Complex-Exponential BEM (GCE-BEM outperforms a Complex-Exponential BEM (CE-BEM and a polynomial BEM in terms of Mean Squared Error (MSE. Besides, the MSE of the CE-BEM decreases gradually as the number of basis functions increases. The GCE-BEM has a satisfactory performance with the serious fading channel.

  6. Robust Distributed Kalman Filter for Wireless Sensor Networks with Uncertain Communication Channels

    Directory of Open Access Journals (Sweden)

    Du Yong Kim

    2012-01-01

    Full Text Available We address a state estimation problem over a large-scale sensor network with uncertain communication channel. Consensus protocol is usually used to adapt a large-scale sensor network. However, when certain parts of communication channels are broken down, the accuracy performance is seriously degraded. Specifically, outliers in the channel or temporal disconnection are avoided via proposed method for the practical implementation of the distributed estimation over large-scale sensor networks. We handle this practical challenge by using adaptive channel status estimator and robust L1-norm Kalman filter in design of the processor of the individual sensor node. Then, they are incorporated into the consensus algorithm in order to achieve the robust distributed state estimation. The robust property of the proposed algorithm enables the sensor network to selectively weight sensors of normal conditions so that the filter can be practically useful.

  7. Networked control of discrete-time linear systems over lossy digital communication channels

    Science.gov (United States)

    Jin, Fang; Zhao, Guang-Rong; Liu, Qing-Quan

    2013-12-01

    This article addresses networked control problems for linear time-invariant systems. The insertion of the digital communication network inevitably leads to packet dropout, time delay and quantisation error. Due to data rate limitations, quantisation error is not neglected. In particular, the case where the sensors and controllers are geographically separated and connected via noisy, bandwidth-limited digital communication channels is considered. A fundamental limitation on the data rate of the channel for mean-square stabilisation of the closed-loop system is established. Sufficient conditions for mean-square stabilisation are derived. It is shown that there exists a quantisation, coding and control scheme to stabilise the unstable system over packet dropout communication channels if the data rate is larger than the lower bound proposed in our result. An illustrative example is given to demonstrate the effectiveness of the proposed conditions.

  8. On Communications under Stochastic Energy Harvesting with Noisy Channel State Information

    KAUST Repository

    Zenaidi, Mohamed Ridha

    2017-02-07

    In energy harvesting communications, the transmitters have to adapt transmission to the availability of energy harvested during communication. The performance of the transmission depends on the channel conditions which vary randomly due environmental changes. In this paper, we consider the problem of power allocation taking into account the energy arrivals over time and imperfect channel state information (CSI) available at the transmitter, in order to maximize the throughput. Differently from previous work, the CSI at the transmitter is not perfect and may include estimation errors. We solve this problem with respect to energy harvesting constraints. We determine the optimal power policy in the case where the channel is perfectly known at the receiver. Furthermore, a study of the asymptotic behavior of the communication system is proposed. Specifically, we analyze the average throughput (AT) in a system where the average recharge rate (ARR) is asymptotically small and when it is very high. Selected numerical results are provided to illustrate our analysis.

  9. Can combining web and mobile communication channels reveal concealed customer value?

    OpenAIRE

    Bothorel, Grégoire; Vanheems, Régine; Guérin, Anne

    2015-01-01

    International audience; Many firms have implemented a customer-value based segmentation to improve the efficiency of MARCOM campaigns as part of their long term customer relationship strategies (Kumar 2010, Thomas et al. 2005).If distribution channel addition may increase the intrinsic customer value (Kumar 2005, Rangaswamy 2005) in a US context as well as in a French context (Vanheems 2009), few studies have been conducted about the impact of adding a new communication channel during the sam...

  10. Power Adaptive Feedback Communication over an Additive Individual Noise Sequence Channel

    OpenAIRE

    Lomnitz, Yuval; Feder, Meir

    2009-01-01

    We consider a real-valued additive channel with an individual unknown noise sequence. We present a simple sequential communication scheme based on the celebrated Schalkwijk-Kailath scheme, which varies the transmit power according to the power of the sequence, so that asymptotically the relation between the SNR and the rate matches the Gaussian channel capacity 1/2 log(1+SNR)for almost every noise sequence.

  11. On Optimal Input Design and Model Selection for Communication Channels

    Energy Technology Data Exchange (ETDEWEB)

    Li, Yanyan [ORNL; Djouadi, Seddik M [ORNL; Olama, Mohammed M [ORNL

    2013-01-01

    In this paper, the optimal model (structure) selection and input design which minimize the worst case identification error for communication systems are provided. The problem is formulated using metric complexity theory in a Hilbert space setting. It is pointed out that model selection and input design can be handled independently. Kolmogorov n-width is used to characterize the representation error introduced by model selection, while Gel fand and Time n-widths are used to represent the inherent error introduced by input design. After the model is selected, an optimal input which minimizes the worst case identification error is shown to exist. In particular, it is proven that the optimal model for reducing the representation error is a Finite Impulse Response (FIR) model, and the optimal input is an impulse at the start of the observation interval. FIR models are widely popular in communication systems, such as, in Orthogonal Frequency Division Multiplexing (OFDM) systems.

  12. Multiple-User Quantum Information Theory for Optical Communication Channels

    Science.gov (United States)

    2008-06-01

    to this day. He later encouraged (and trained) me to participate in the Physics Olympiad, which led me to make it through all the levels of selection...optimal, homodyne, and hetero- dyne reception versus transmitter power P , with P0 ≡ 2π~c2L2/ AtAr used for the reference power...the constraints on the available physical resources. In most communication systems, the transfer of information is done by superimposing the

  13. Safety assessment of inter-channel / inter-system digital communications: A defensive measures approach

    International Nuclear Information System (INIS)

    Thuy, N. N. Q.

    2006-01-01

    Inappropriately designed inter-channel and inter-system digital communications could initiate common cause failure of multiple channels or multiple systems. Defensive measures were introduced in EPRI report TR-1002835 (Guideline for Performing Defense-in-Depth and Diversity Assessments for Digital Upgrades) to assess, on a deterministic basis, the susceptibility of digital systems architectures to common-cause failures. This paper suggests how this approach could be applied to assess inter-channel and inter-system digital communications from a safety standpoint. The first step of the approach is to systematically identify the so called 'influence factors' that one end of the data communication path can have on the other. Potential factors to be considered would typically include data values, data volumes and data rates. The second step of the approach is to characterize the ways possible failures of a given end of the communication path could affect these influence factors (e.g., incorrect data values, excessive data rates, time-outs, incorrect data volumes). The third step is to analyze the designed-in measures taken to guarantee independence of the other end. In addition to classical error detection and correction codes, typical defensive measures are one-way data communication, fixed-rate data communication, fixed-volume data communication, validation of data values. (authors)

  14. 80-Channel Multiplexer-Demultiplexer Module for DWDM Communications using Hybrid AWG -- Interleaver Technology

    Science.gov (United States)

    Rablau, Corneliu; Bredthauer, Lance

    2007-10-01

    Aside from the more traditional data, voice and e-mail communications, new bandwidth intensive applications in the larger consumer markets, such as music, digital pictures and movies, have led to an explosive increase in the demand for transmission capacity for optical communications networks. This has resulted in a widespread deployment of Dense Wavelength Division Multiplexing (DWDM) as a means of increasing the communications capacity by multiplexing and transmitting signals of different wavelengths (establishing multiple communication channels) through a single strand of fiber. We report on the design, assembly and characterization of a 50-GHz, 80-channel Mux-Demux module for DWDM systems. The module has been assembled from two commercially available 100 GHz, 40-channel Array Waveguide Grating (AWG) modules and a 50-GHz to 100-GHz interleaver. Relevant performance parameters such as insertion loss, channel uniformity, next-channel isolation (crosstalk) and integrated cross-talk are presented and discussed in contrast with the performance of other competing technologies such as Thin-Film-Filter-based Mux-Demux devices.

  15. Communication systems, transceivers, and methods for generating data based on channel characteristics

    Science.gov (United States)

    Forman, Michael A; Young, Derek

    2012-09-18

    Examples of methods for generating data based on a communications channel are described. In one such example, a processing unit may generate a first vector representation based in part on at least two characteristics of a communications channel. A constellation having at least two dimensions may be addressed with the first vector representation to identify a first symbol associated with the first vector representation. The constellation represents a plurality of regions, each region associated with a respective symbol. The symbol may be used to generate data, which may stored in an electronic storage medium and used as a cryptographic key or a spreading code or hopping sequence in a modulation technique.

  16. Statistical mechanical analysis of the linear vector channel in digital communication

    International Nuclear Information System (INIS)

    Takeda, Koujin; Hatabu, Atsushi; Kabashima, Yoshiyuki

    2007-01-01

    A statistical mechanical framework to analyze linear vector channel models in digital wireless communication is proposed for a large system. The framework is a generalization of that proposed for code-division multiple-access systems in Takeda et al (2006 Europhys. Lett. 76 1193) and enables the analysis of the system in which the elements of the channel transfer matrix are statistically correlated with each other. The significance of the proposed scheme is demonstrated by assessing the performance of an existing model of multi-input multi-output communication systems

  17. Eavesdropping on the Bostroem-Filbinger Communication Protocol in Noisy Quantum Channel

    OpenAIRE

    Cai, Qing-yu

    2004-01-01

    We show an eavesdropping scheme on Bostr\\UNICODE{0xf6}m-Felbinger communication protocol (called ping-pong protocol) [Phys. Rev. Lett. 89, 187902 (2002)] in an ideal quantum channel. A measurement attack can be perfectly used to eavesdrop Alice's information instead of a most general quantum operation attack. In a noisy quantum channel, the direct communication is forbidden. We present a quantum key distribution protocol based on the ping-pong protocol, which can be used in a low noisy quantu...

  18. INVESTIGATION OF ADS-B MESSAGES TRAFFIC VIA SATELLITE COMMUNICATION CHANNEL

    Directory of Open Access Journals (Sweden)

    Volodymyr Kharchenko

    2014-12-01

    Full Text Available For modelling of ADS-B messages transmition with the help of low-orbit satellite complex Іrіdіumdifferent models of communication channel "Aircraft-to-Satellites-to-Ground Stations" were built using NetCrackerProfessіonal 4.1 software. Influence of aircraft and satellites amount on average link utilization and message travellingtime was studied for telecommunication channels with intersatellite link and bent-pipe architecture. The effect ofcommunication channel "saturation" during simultaneous data transmission through a satellite communicationchannel from many planes was investigated.

  19. Low-sampling-rate M-ary multiple access UWB communications in multipath channels

    KAUST Repository

    Alkhodary, Mohammad T.

    2015-08-31

    The desirable characteristics of ultra-wideband (UWB) technology are challenged by formidable sampling frequency, performance degradation in the presence of multi-user interference, and complexity of the receiver due to the channel estimation process. In this paper, a low-rate-sampling technique is used to implement M-ary multiple access UWB communications, in both the detection and channel estimation stages. A novel approach is used for multiple-access-interference (MAI) cancelation for the purpose of channel estimation. Results show reasonable performance of the proposed receiver for different number of users operating many times below Nyquist rate.

  20. Low-sampling-rate M-ary multiple access UWB communications in multipath channels

    KAUST Repository

    Alkhodary, Mohammad T.; Ballal, Tarig; Al-Naffouri, Tareq Y.; Muqaibel, Ali H.

    2015-01-01

    The desirable characteristics of ultra-wideband (UWB) technology are challenged by formidable sampling frequency, performance degradation in the presence of multi-user interference, and complexity of the receiver due to the channel estimation process. In this paper, a low-rate-sampling technique is used to implement M-ary multiple access UWB communications, in both the detection and channel estimation stages. A novel approach is used for multiple-access-interference (MAI) cancelation for the purpose of channel estimation. Results show reasonable performance of the proposed receiver for different number of users operating many times below Nyquist rate.

  1. Channels of health communications used among Korean and Asian Indian older adults.

    Science.gov (United States)

    Lee, Ji Seon

    2010-01-01

    According to Healthy People 2010, health communication is an important tool to reduce health disparities. Communication channels in which people prefer to receive health information may differ by race/ethnicity. One of the main challenges in designing an effective health communication program is to identify the most trusted and most often used channels of health information by Asian older adults. The aim of this study is to determine which health communication channels can be used to promote healthy lifestyles among older adults. A non-probability, convenience-sampling technique was used to recruit Korean (n = 9) and Asian Indian (n = 9) older adults from two senior centers in New York City. The findings from the two focus groups identified three distinct channels used by Asian older adults when obtaining health information: interpersonal (i.e., health care providers, word of mouth), mass media (i.e., ethnic mass media sources), and community specific (i.e., religious organizations, community centers). Health communication is an important area for prevention. Increased efforts are needed to develop culturally appropriate health messages and equally important to deliver these messages in the context in which Asian older adults trust and use the most.

  2. The Channel Estimation and Modeling in High Altitude Platform Station Wireless Communication Dynamic Network

    Directory of Open Access Journals (Sweden)

    Xiaoyang Liu

    2017-01-01

    Full Text Available In order to analyze the channel estimation performance of near space high altitude platform station (HAPS in wireless communication system, the structure and formation of HAPS are studied in this paper. The traditional Least Squares (LS channel estimation method and Singular Value Decomposition-Linear Minimum Mean-Squared (SVD-LMMS channel estimation method are compared and investigated. A novel channel estimation method and model are proposed. The channel estimation performance of HAPS is studied deeply. The simulation and theoretical analysis results show that the performance of the proposed method is better than the traditional methods. The lower Bit Error Rate (BER and higher Signal Noise Ratio (SNR can be obtained by the proposed method compared with the LS and SVD-LMMS methods.

  3. Compensating for Channel Fading in DS-CDMA Communication Systems Employing ICA Neural Network Detectors

    Directory of Open Access Journals (Sweden)

    David Overbye

    2005-06-01

    Full Text Available In this paper we examine the impact of channel fading on the bit error rate of a DS-CDMA communication system. The system employs detectors that incorporate neural networks effecting methods of independent component analysis (ICA, subspace estimation of channel noise, and Hopfield type neural networks. The Rayleigh fading channel model is used. When employed in a Rayleigh fading environment, the ICA neural network detectors that give superior performance in a flat fading channel did not retain this superior performance. We then present a new method of compensating for channel fading based on the incorporation of priors in the ICA neural network learning algorithms. When the ICA neural network detectors were compensated using the incorporation of priors, they give significantly better performance than the traditional detectors and the uncompensated ICA detectors. Keywords: CDMA, Multi-user Detection, Rayleigh Fading, Multipath Detection, Independent Component Analysis, Prior Probability Hebbian Learning, Natural Gradient

  4. Differential phase-shift keying and channel equalization in free space optical communication system

    Science.gov (United States)

    Zhang, Dai; Hao, Shiqi; Zhao, Qingsong; Wan, Xiongfeng; Xu, Chenlu

    2018-01-01

    We present the performance benefits of differential phase-shift keying (DPSK) modulation in eliminating influence from atmospheric turbulence, especially for coherent free space optical (FSO) communication with a high communication rate. Analytic expression of detected signal is derived, based on which, homodyne detection efficiency is calculated to indicate the performance of wavefront compensation. Considered laser pulses always suffer from atmospheric scattering effect by clouds, intersymbol interference (ISI) in high-speed FSO communication link is analyzed. Correspondingly, the channel equalization method of a binormalized modified constant modulus algorithm based on set-membership filtering (SM-BNMCMA) is proposed to solve the ISI problem. Finally, through the comparison with existing channel equalization methods, its performance benefits of both ISI elimination and convergence speed are verified. The research findings have theoretical significance in a high-speed FSO communication system.

  5. Optimized optical wireless channel for indoor and intra-vehicle communications: power distribution and SNR analysis

    Science.gov (United States)

    Shaaban, Rana; Faruque, Saleh

    2018-01-01

    Light emitting diodes - LEDs are modernizing the indoor illumination and replacing current incandescent and fluorescent lamps rapidly. LEDs have multiple advantages such as extremely high energy efficient, longer lifespan, and lower heat generation. Due to the ability to switch to different light intensity at a very fast rate, LED has given rise to a unique communication technology (visible light communication - VLC) used for high speed data transmission. By studying various kinds of commonly used VLC channel analysis: diffuse and line of sight channels, we presented a simply improved indoor and intra-vehicle visible light communication transmission model. Employing optical wireless communications within the vehicle, not only enhance user mobility, but also alleviate radio frequency interference, and increase efficiency by lowering the complexity of copper cabling. Moreover, a solution to eliminate ambient noise caused by environmental conditions is examined by using optical differential receiver. The simulation results show the improved received power distribution and signal to noise ratio - SNR.

  6. Implementation of an Ethernet-Based Communication Channel for the Patmos Processor

    DEFF Research Database (Denmark)

    Pezzarossa, Luca; Kenn Toft, Jakob; Lønbæk, Jesper

    The Patmos processor, which is used as the intellectual property of the T-CREST platform, is only equipped with a RS-232 serial port for communication with the outside world. The serial port is a minimal input/output device with a limited speed and without native networking features. An Ethernet 10....../100BASE-T IEEE 802.3 based communication channel is a reliable and high speed communication interface (10/100 Mbits/s) that also supports networking. This technical report presents an implementation of an Ethernet-based communication channel for the Patmos processor, targeting the Terasic DE2......-115 development board. We have designed the hardware to interface the EthMac Ethernet controller from OpenCores to Patmos and to the physical chip of the development board, and we have implemented a software library to drive the controller and to support some essential protocols. The design was implemented...

  7. Channel coding and data compression system considerations for efficient communication of planetary imaging data

    Science.gov (United States)

    Rice, R. F.

    1974-01-01

    End-to-end system considerations involving channel coding and data compression are reported which could drastically improve the efficiency in communicating pictorial information from future planetary spacecraft. In addition to presenting new and potentially significant system considerations, this report attempts to fill a need for a comprehensive tutorial which makes much of this very subject accessible to readers whose disciplines lie outside of communication theory.

  8. TAM AIRLINES ON TWITTER: COMMUNICATION CHANNEL OR SOCIAL NETWORK?

    Directory of Open Access Journals (Sweden)

    Cynthia Harumy Watanabe Corrêa

    2010-12-01

    Full Text Available The research emphasizes the social appropriation of Information and Communication Technologies by the Brazilian aviation industry, through a case study of communication strategies of TAM on the social networking site Twitter. TAM is a leader in the Brazilian domestic market and gradually conquering its space in Mercosul. This is an exploratory research, based on content analysis of messages sent to the company profile on Twitter, in order to check whether indeed the consolidation of a social network between TAM and its followers. We analyzed all messages posted since July 3, 2009, the date of the first post in the company profile, until the day January 31, 2010. Among the subjects discussed, there was the predominance of information and promotions. The study concludes that, under Twitter, TAM has yet reached a high degree of social interaction with his followers, because the major number of messages is directed to promotional marketing.

  9. Analysis of multipath channel fading techniques in wireless communication systems

    Science.gov (United States)

    Mahender, Kommabatla; Kumar, Tipparti Anil; Ramesh, K. S.

    2018-04-01

    Multipath fading occurs in any environment where there is multipath propagation and there is some movement of elements within the radio communications system. This may include the radio transmitter or receiver position, or in the elements that give rise to the reflections. The multipath fading can often be relatively deep, i.e. the signals fade completely away, whereas at other times the fading may not cause the signal to fall below a useable strength. Multipath fading may also cause distortion to the radio signal. As the various paths that can be taken by the signals vary in length, the signal transmitted at a particular instance will arrive at the receiver over a spread of times. This can cause problems with phase distortion and inter symbol interference when data transmissions are made. As a result, it may be necessary to incorporate features within the radio communications system that enables the effects of these problems to be minimized. This paper analyses the effects of various types of multipath fading in wireless transmission system.

  10. Challenges in sending large radiology images over military communications channels

    Science.gov (United States)

    Cleary, Kevin R.; Levine, Betty A.; Norton, Gary S.; Mundur, Padmavathi V.

    1997-05-01

    In cooperation with the US Army, Georgetown University Medical Center (GUMC) deployed a teleradiology network to sites in Bosnia-Herzegovina, Hungary, and Germany in early 1996. This deployment was part of Operation Primetime III, a military project to provide state-of-the-art medical care to the 20,000 US troops stationed in Bosnia-Herzegovina.In a three-month time frame from January to April 1996, the Imaging Sciences and Information Systems (ISIS) Center at GUMC worked with the Army to design, develop, and deploy a teleradiology network for the digital storage and transmission of radiology images. This paper will discuss some of the problems associated with sending large files over communications networks with significant delays such as those introduced by satellite transmissions.Radiology images of up to 10 megabytes are acquired, stored, and transmitted over the wide area network (WAN). The WAN included leased lines from Germany to Hungary and a satellite link form Germany to Bosnia-Herzegovina. The communications links provided at least a T-1 bandwidth. The satellite link introduces a round-trip delay of approximately 500 milliseconds. This type of high bandwidth, high delay network is called a long fat network. The images are transferred across this network using the Transmission Control Protocol (TCP/IP). By modifying the TCP/IP software to increase the window size, the throughput of the satellite link can be greatly improved.

  11. Discrete Input Signaling for MISO Visible Light Communication Channels

    KAUST Repository

    Arfaoui, Mohamed Amine

    2017-05-12

    In this paper, we study the achievable secrecy rate of visible light communication (VLC) links for discrete input distributions. We consider single user single eavesdropper multiple-input single-output (MISO) links. In addition, both beamforming and robust beamforming are considered. In the former case, the location of the eavesdropper is assumed to be known, whereas in the latter case, the location of the eavesdropper is unknown. We compare the obtained results with those achieved by some continuous distributions including the truncated generalized normal (TGN) distribution and the uniform distribution. We numerically show that the secrecy rate achieved by the discrete input distribution with a finite support is significantly improved as compared to those achieved by the TGN and the uniform distributions.

  12. Possible existence of optical communication channels in the brain

    Science.gov (United States)

    Kumar, Sourabh; Boone, Kristine; Tuszyński, Jack; Barclay, Paul; Simon, Christoph

    2016-11-01

    Given that many fundamental questions in neuroscience are still open, it seems pertinent to explore whether the brain might use other physical modalities than the ones that have been discovered so far. In particular it is well established that neurons can emit photons, which prompts the question whether these biophotons could serve as signals between neurons, in addition to the well-known electro-chemical signals. For such communication to be targeted, the photons would need to travel in waveguides. Here we show, based on detailed theoretical modeling, that myelinated axons could serve as photonic waveguides, taking into account realistic optical imperfections. We propose experiments, both in vivo and in vitro, to test our hypothesis. We discuss the implications of our results, including the question whether photons could mediate long-range quantum entanglement in the brain.

  13. Experimental Evaluation of Wireless Communication Channels under Radiation Environment

    International Nuclear Information System (INIS)

    Wang, Quan; Bari, Ataul; Deng, Changjian; Li, Liquan

    2014-01-01

    Deployment of wireless systems in nuclear power plants has attracted a lot of attention recently. However, before wireless systems can be installed in a nuclear power plant, it is necessary to evaluate the effect of radiation environment on electromagnetic wave which is the communication media for all radio wave based wireless systems. This is particular important if the wireless systems are expected to work in a harsh and radioactive environment following a severe accident. This paper presents some results of an experiment for evaluating the effect of radiation on electromagnetic wave. The experiments involve placing transmitter antenna and receiver antenna in a hot cell with variable strength of radiation to study the attenuation effects of the radioactive media. The results indicate that radiation does not effect on the electromagnetic wave propagation. This fact should be considered during the design and deployment wireless systems in a potentially radioactive environment

  14. Position-based coding and convex splitting for private communication over quantum channels

    Science.gov (United States)

    Wilde, Mark M.

    2017-10-01

    The classical-input quantum-output (cq) wiretap channel is a communication model involving a classical sender X, a legitimate quantum receiver B, and a quantum eavesdropper E. The goal of a private communication protocol that uses such a channel is for the sender X to transmit a message in such a way that the legitimate receiver B can decode it reliably, while the eavesdropper E learns essentially nothing about which message was transmitted. The ɛ -one-shot private capacity of a cq wiretap channel is equal to the maximum number of bits that can be transmitted over the channel, such that the privacy error is no larger than ɛ \\in (0,1). The present paper provides a lower bound on the ɛ -one-shot private classical capacity, by exploiting the recently developed techniques of Anshu, Devabathini, Jain, and Warsi, called position-based coding and convex splitting. The lower bound is equal to a difference of the hypothesis testing mutual information between X and B and the "alternate" smooth max-information between X and E. The one-shot lower bound then leads to a non-trivial lower bound on the second-order coding rate for private classical communication over a memoryless cq wiretap channel.

  15. Relay Selections for Security and Reliability in Mobile Communication Networks over Nakagami-m Fading Channels

    Directory of Open Access Journals (Sweden)

    Hongji Huang

    2017-01-01

    Full Text Available This paper studies the relay selection schemes in mobile communication system over Nakagami-m channel. To make efficient use of licensed spectrum, both single relay selection (SRS scheme and multirelays selection (MRS scheme over the Nakagami-m channel are proposed. Also, the intercept probability (IP and outage probability (OP of the proposed SRS and MRS for the communication links depending on realistic spectrum sensing are derived. Furthermore, this paper assesses the manifestation of conventional direct transmission scheme to compare with the proposed SRS and MRS ones based on the Nakagami-m channel, and the security-reliability trade-off (SRT performance of the proposed schemes and the conventional schemes is well investigated. Additionally, the SRT of the proposed SRS and MRS schemes is demonstrated better than that of direct transmission scheme over the Nakagami-m channel, which can protect the communication transmissions against eavesdropping attacks. Additionally, simulation results show that our proposed relay selection schemes achieve better SRT performance than that of conventional direct transmission over the Nakagami-m channel.

  16. Communicating with first year students; so many channels but is anyone listening? A Practice Report

    Directory of Open Access Journals (Sweden)

    Jason Lodge

    2010-07-01

    Full Text Available Communicating with first year students has become a far more complex prospect in the digital age. There is a lot of competition for limited attentional resources from media sources in almost endless channels. Getting important messages to students when there is so much competing information is a difficult prospect for academic and professional divisions of the university alike. Students’ preferences for these communication channels are not well understood and are constantly changing with the introduction of new technology. A first year group was surveyed about their use and preference for various sources of information. Students were generally positive about the use of social networking and other new online media but strongly preferred more established channels for official academic and administrative information. A discussion of the findings and recommendations follows.

  17. Performance limits of energy harvesting communications under imperfect channel state information

    KAUST Repository

    Zenaidi, Mohamed Ridha

    2016-07-26

    In energy harvesting communications, the transmitters have to adapt transmission to availability of energy harvested during the course of communication. The performance of the transmission depends on the channel conditions which vary randomly due to mobility and environmental changes. In this paper, we consider the problem of power allocation taking into account the energy arrivals over time and the degree of channel state information (CSI) available at the transmitter, in order to maximize the throughput. Differently from previous work, the CSI at the transmitter is not perfect and may include estimation errors. We solve this problem with respect to the causality and energy storage constraints. We determine the optimal offline policy in the case where the channel is assumed to be perfectly known at the receiver. Also, we obtain the power policy when the transmitter has no CSI. Furthermore, we analyze the asymptotic average throughput in a system where the average recharge rate goes asymptotically to zero. © 2016 IEEE.

  18. Shannon Meets Fick on the Microfluidic Channel: Diffusion Limit to Sum Broadcast Capacity for Molecular Communication.

    Science.gov (United States)

    Bicen, A Ozan; Lehtomaki, Janne J; Akyildiz, Ian F

    2018-03-01

    Molecular communication (MC) over a microfluidic channel with flow is investigated based on Shannon's channel capacity theorem and Fick's laws of diffusion. Specifically, the sum capacity for MC between a single transmitter and multiple receivers (broadcast MC) is studied. The transmitter communicates by using different types of signaling molecules with each receiver over the microfluidic channel. The transmitted molecules propagate through microfluidic channel until reaching the corresponding receiver. Although the use of different types of molecules provides orthogonal signaling, the sum broadcast capacity may not scale with the number of the receivers due to physics of the propagation (interplay between convection and diffusion based on distance). In this paper, the performance of broadcast MC on a microfluidic chip is characterized by studying the physical geometry of the microfluidic channel and leveraging the information theory. The convergence of the sum capacity for microfluidic broadcast channel is analytically investigated based on the physical system parameters with respect to the increasing number of molecular receivers. The analysis presented here can be useful to predict the achievable information rate in microfluidic interconnects for the biochemical computation and microfluidic multi-sample assays.

  19. Is channel segmentation necessary to reach a multiethnic population with weight-related health promotion? An analysis of use and perception of communication channels.

    Science.gov (United States)

    Hartman, Marieke A; Nierkens, Vera; Cremer, Stephan W; Verhoeff, Arnoud; Stronks, Karien

    2015-01-01

    To explore similarities and differences in the use and perception of communication channels to access weight-related health promotion among women in three ethnic minority groups. The ultimate aim was to determine whether similar channels might reach ethnic minority women in general or whether segmentation to ethnic groups would be required. Eight ethnically homogeneous focus groups were conducted among 48 women of Ghanaian, Antillean/Aruban, or Afro-Surinamese background living in Amsterdam. Our questions concerned which communication channels they usually used to access weight-related health advice or information about programs and whose information they most valued. The content analysis of data was performed. The participants mentioned four channels - regular and traditional health care, general or ethnically specific media, multiethnic and ethnic gatherings, and interpersonal communication with peers in the Netherlands and with people in the home country. Ghanaian women emphasized ethnically specific channels (e.g., traditional health care, Ghanaian churches). They were comfortable with these channels and trusted them. They mentioned fewer general channels - mainly limited to health care - and if discussed, negative perceptions were expressed. Antillean women mentioned the use of ethnically specific channels (e.g., communication with Antilleans in the home country) on balance with general audience-oriented channels (e.g., regular health care). Perceptions were mixed. Surinamese participants discussed, in a positive manner, the use of general audience-oriented channels, while they said they did not use traditional health care or advice from Surinam. Local language proficiency, time resided in the Netherlands, and approaches and messages received seemed to explain channel use and perception. The predominant differences in channel use and perception among the ethnic groups indicate a need for channel segmentation to reach a multiethnic target group with weight

  20. Polarization vision in cuttlefish in a concealed communication channel?

    Science.gov (United States)

    Shashar; Rutledge; Cronin

    1996-01-01

    Polarization sensitivity is well documented in marine animals, but its function is not yet well understood. Of the cephalopods, squid and octopus are known to be sensitive to the orientation of polarization of incoming light. This sensitivity arises from the orthogonal orientation of neighboring photoreceptors. Electron microscopical examination of the retina of the cuttlefish Sepia officinalis L. revealed the same orthogonal structure, suggesting that cuttlefish are also sensitive to linearly polarized light. Viewing cuttlefish through an imaging polarized light analyzer revealed a prominent polarization pattern on the arms, around the eyes and on the forehead of the animals. The polarization pattern disappeared when individuals lay camouflaged on the bottom and also during extreme aggression display, attacks on prey, copulation and egg-laying behavior in females. In behavioral experiments, the responses of cuttlefish to their images reflected from a mirror changed when the polarization patterns of the reflected images were distorted. These results suggest that cuttlefish use polarization vision and display for intraspecific recognition and communication.

  1. CSR Communication - An Employee Perspective : Tailoring Internal Communication using Employee Preferences for Content, Style and Channel.

    OpenAIRE

    Jonsson, Viktoria; Linnér, Rebecka

    2016-01-01

    Corporate Social Responsibility (CSR) represents a theory and practice that is well-known and communicating its content has shown to play an important role in order to exploit its advantages and engage stakeholders on CSR issues. Even though, CSR communication has shown to be a real challenge, since corporations are encouraged to engage in CSR, but not to communicate too loud about this engagement. This study was inspired by Jenny Dawkins (2005) and her initial idea that tailoring CSR message...

  2. What You Don't Know Won't Hurt Me: Impression Management Functions of Communication Channels in Relationships.

    Science.gov (United States)

    O'Sullivan, Patrick B.

    2000-01-01

    Addresses the implications of interpersonal communication technology use for personal relationships. Tests elements of an impression management model, which specifies the processes and outcomes of strategic uses of channel and message for self-presentational goals. Supports a functional perspective that views mediated communication channels as a…

  3. Two-channel spin-chain communication line and simple quantum gates

    Science.gov (United States)

    Stolze, J.; Zenchuk, A. I.

    2017-08-01

    We consider the remote creation of a mixed state in a one-qubit receiver connected to two two-qubit senders via different channels. Channels are assumed to be chains of spins (qubits) with nearest-neighbor interactions, no external fields are being applied. The problem of sharing the creatable region of the receiver's state-space between two senders is considered for a communication line with the receiver located asymmetrically with respect to these senders (asymmetric communication line). An example of a quantum register realizing simple functions is constructed on the basis of a symmetric communication line. In that setup, the initial states of the two senders serve as input and control signals, respectively, while the state of the receiver at a proper time instant is considered as the output signal.

  4. Blind channel estimation for MLSE receiver in high speed optical communications: theory and ASIC implementation.

    Science.gov (United States)

    Gorshtein, Albert; Levy, Omri; Katz, Gilad; Sadot, Dan

    2013-09-23

    Blind channel estimation is critical for digital signal processing (DSP) compensation of optical fiber communications links. The overall channel consists of deterministic distortions such as chromatic dispersion, as well as random and time varying distortions including polarization mode dispersion and timing jitter. It is critical to obtain robust acquisition and tracking methods for estimating these distortions effects, which, in turn, can be compensated by means of DSP such as Maximum Likelihood Sequence Estimation (MLSE). Here, a novel blind estimation algorithm is developed, accompanied by inclusive mathematical modeling, and followed by extensive set of real time experiments that verify quantitatively its performance and convergence. The developed blind channel estimation is used as the basis of an MLSE receiver. The entire scheme is fully implemented in a 65 nm CMOS Application Specific Integrated Circuit (ASIC). Experimental measurements and results are presented, including Bit Error Rate (BER) measurements, which demonstrate the successful data recovery by the MLSE ASIC under various channel conditions and distances.

  5. Studies on diversion cross-flow between two parallel channels communicating by a lateral slot. II

    International Nuclear Information System (INIS)

    Tapucu, A.; Merilo, M.

    1977-01-01

    The axial pressure variations of two parallel channels with single phase flows communicating by a long lateral slot have been studied experimentally. Using mass and momentum conservation principles, the axial pressure variations have been derived in terms of two parameters ksub(d) and ksub(r), for donor and recipient channels, respectively. These parameters include the combined effect of fluid transferred from donor to recipient channel, and drag force brought on by the connection gap, and are functions of the velocities and slot geometry parameters. A pressure difference oscillation between channels along the slot has been detected which is sinusoidal with wave lengths which seem to be a function of the gap clearance. (Auth.)

  6. A tone-aided dual vestigial sideband system for digital communications on fading channels

    Science.gov (United States)

    Hladik, Stephen M.; Saulnier, Gary J.; Rafferty, William

    1989-01-01

    A spectrally efficient tone-aided dual vestigial sideband (TA/DVSB) system for digital data communications on fading channels is presented and described analytically. This PSK (phase-shift-keying) system incorporates a feed-forward, tone-aided demodulation technique to compensate for Doppler frequency shift and channel- induced, multipath fading. In contrast to other tone-in-band-type systems, receiver synchronization is derived from the complete data VSBs. Simulation results for the Rician fading channel are presented. These results demonstrate the receiver's ability to mitigate performance degradation due to fading and to obtain proper data carrier synchronization, suggesting that the proposed TA/DVSB system has promise for this application. Simulated BER (bit-error rate) data indicate that the TA/DVSB system effectively alleviates the channel distortions of the land mobile satellite application.

  7. Is channel segmentation necessary to reach a multiethnic population with weight-related health promotion? An analysis of use and perception of communication channels

    NARCIS (Netherlands)

    Hartman, M.A.; Nierkens, V.; Cremer, S.W.; Verhoeff, A.; Stronks, K.

    2015-01-01

    Objective. To explore similarities and differences in the use and perception of communication channels to access weight-related health promotion among women in three ethnic minority groups. The ultimate aim was to determine whether similar channels might reach ethnic minority women in general or

  8. Is channel segmentation necessary to reach a multiethnic population with weight-related health promotion? An analysis of use and perception of communication channels

    NARCIS (Netherlands)

    Hartman, Marieke A.; Nierkens, Vera; Cremer, Stephan W.; Verhoeff, Arnoud; Stronks, Karien

    2015-01-01

    To explore similarities and differences in the use and perception of communication channels to access weight-related health promotion among women in three ethnic minority groups. The ultimate aim was to determine whether similar channels might reach ethnic minority women in general or whether

  9. Channel modelling and performance analysis of V2I communication systems in blind bend scattering environments

    KAUST Repository

    Chelli, Ali

    2014-01-01

    In this paper, we derive a new geometrical blind bend scattering model for vehicle-to- infrastructure (V2I) communications. The proposed model takes into account single-bounce and double- bounce scattering stemming from fixed scatterers located on both sides of a curved street. Starting from the geometrical blind bend model, the exact expression of the angle of departure (AOD) is derived. Based on this expression, the probability density function (PDF) of the AOD and the Doppler power spectrum are determined. Analytical expressions for the channel gain and the temporal autocorrelation function (ACF) are provided under non-line-of-sight (NLOS) conditions. Additionally, we investigate the impact of the position of transmitting vehicle relatively to the receiving road-side unit on the channel statistics. Moreover, we study the performance of different digital modulations over a sum of singly and doubly scattered (SSDS) channel. Note that the proposed V2I channel model falls under the umbrella of SSDS channels since the transmitted signal undergoes a combination of single-bounce and double-bounce scattering. We study some characteristic quantities of SSDS channels and derive expressions for the average symbol error probability of several modulation schemes over SSDS channels with and without diversity combining. The validity of these analytical expressions is confirmed by computer-based simulations.

  10. Modeling of Non-WSSUS Double-Rayleigh Fading Channels for Vehicular Communications

    Directory of Open Access Journals (Sweden)

    Carlos A. Gutiérrez

    2017-01-01

    Full Text Available This paper deals with the modeling of nonstationary time-frequency (TF dispersive multipath fading channels for vehicle-to-vehicle (V2V communication systems. As a main contribution, the paper presents a novel geometry-based statistical channel model that facilitates the analysis of the nonstationarities of V2V fading channels arising at a small-scale level due to the time-varying nature of the propagation delays. This new geometrical channel model has been formulated following the principles of plane wave propagation (PWP and assuming that the transmitted signal reaches the receiver antenna through double interactions with multiple interfering objects (IOs randomly located in the propagation area. As a consequence of such interactions, the first-order statistics of the channel model’s envelope are shown to follow a worse-than-Rayleigh distribution; specifically, they follow a double-Rayleigh distribution. General expressions are derived for the envelope and phase distributions, four-dimensional (4D TF correlation function (TF-CF, and TF-dependent delay and Doppler profiles of the proposed channel model. Such expressions are valid regardless of the underlying geometry of the propagation area. Furthermore, a closed-form solution of the 4D TF-CF is presented for the particular case of the geometrical two-ring scattering model. The obtained results provide new theoretical insights into the correlation and spectral properties of small-scale nonstationary V2V double-Rayleigh fading channels.

  11. Energy reduction using multi-channels optical wireless communication based OFDM

    Science.gov (United States)

    Darwesh, Laialy; Arnon, Shlomi

    2017-10-01

    In recent years, an increasing number of data center networks (DCNs) have been built to provide various cloud applications. Major challenges in the design of next generation DC networks include reduction of the energy consumption, high flexibility and scalability, high data rates, minimum latency and high cyber security. Use of optical wireless communication (OWC) to augment the DC network could help to confront some of these challenges. In this paper we present an OWC multi channels communication method that could lead to significant energy reduction of the communication equipment. The method is to convert a high speed serial data stream to many slower and parallel streams and vies versa at the receiver. We implement this concept of multi channels using optical orthogonal frequency division multiplexing (O-OFDM) method. In our scheme, we use asymmetrically clipped optical OFDM (ACO-OFDM). Our results show that the realization of multi channels OFDM (ACO-OFDM) methods reduces the total energy consumption exponentially, as the number of channels transmitted through them rises.

  12. Fixed channel assignment in cellular communication systems considering the whole set of packed patterns

    DEFF Research Database (Denmark)

    Borges, Pedro Manuel F. C.; Vidal, Rene Victor Valqui

    2000-01-01

    This paper addresses the problem of fixed channel assignment in cellular communication systems with nonuniform traffic distribution. The objective of the channel assignment is to minimise the average blocking probability. Methods for finding a good allocation can be based on first building a number...... of flexibility when dealing with extensions to the problem. A neighbouring structure was used, that facilitated the calculations while still allowing for the search in the entire solution space. A summary of extensive numerical experiments is presented. The outcome is an improvement over previous results...

  13. Occupational stress in human computer interaction.

    Science.gov (United States)

    Smith, M J; Conway, F T; Karsh, B T

    1999-04-01

    There have been a variety of research approaches that have examined the stress issues related to human computer interaction including laboratory studies, cross-sectional surveys, longitudinal case studies and intervention studies. A critical review of these studies indicates that there are important physiological, biochemical, somatic and psychological indicators of stress that are related to work activities where human computer interaction occurs. Many of the stressors of human computer interaction at work are similar to those stressors that have historically been observed in other automated jobs. These include high workload, high work pressure, diminished job control, inadequate employee training to use new technology, monotonous tasks, por supervisory relations, and fear for job security. New stressors have emerged that can be tied primarily to human computer interaction. These include technology breakdowns, technology slowdowns, and electronic performance monitoring. The effects of the stress of human computer interaction in the workplace are increased physiological arousal; somatic complaints, especially of the musculoskeletal system; mood disturbances, particularly anxiety, fear and anger; and diminished quality of working life, such as reduced job satisfaction. Interventions to reduce the stress of computer technology have included improved technology implementation approaches and increased employee participation in implementation. Recommendations for ways to reduce the stress of human computer interaction at work are presented. These include proper ergonomic conditions, increased organizational support, improved job content, proper workload to decrease work pressure, and enhanced opportunities for social support. A model approach to the design of human computer interaction at work that focuses on the system "balance" is proposed.

  14. Relay selection in cooperative communication systems over continuous time-varying fading channel

    Directory of Open Access Journals (Sweden)

    Ke Geng

    2017-02-01

    Full Text Available In this paper, we study relay selection under outdated channel state information (CSI in a decode-and-forward (DF cooperative system. Unlike previous researches on cooperative communication under outdated CSI, we consider that the channel varies continuously over time, i.e., the channel not only changes between relay selection and data transmission but also changes during data transmission. Thus the level of accuracy of the CSI used in relay selection degrades with data transmission. We first evaluate the packet error rate (PER of the cooperative system under continuous time-varying fading channel, and find that the PER performance deteriorates more seriously under continuous time-varying fading channel than when the channel is assumed to be constant during data transmission. Then, we propose a repeated relay selection (RRS strategy to improve the PER performance, in which the forwarded data is divided into multiple segments and relay is reselected before the transmission of each segment based on the updated CSI. Finally, we propose a combined relay selection (CRS strategy which takes advantage of three different relay selection strategies to further mitigate the impact of outdated CSI.

  15. PInCom project: SaaS Big Data Platform for and Communication Channels

    Directory of Open Access Journals (Sweden)

    Juan Manuel Lombardo

    2016-03-01

    Full Text Available The problem of optimization will be addressed in this article, based on the premise that the successful implementation of Big Data solutions requires as a determining factor not only effective -it is assumed- but the efficiency of the responsiveness of management information get the best value offered by the digital and technological environment for gaining knowledge. In adopting Big Data strategies should be identified storage technologies and appropriate extraction to enable professionals and companies from different sectors to realize the full potential of the data. A success story is the solution PInCom: Intelligent-Communications Platform that aims customer loyalty by sending multimedia communications across heterogeneous transmission channels.

  16. State estimation and synchronization of pendula systems over digital communication channels

    Science.gov (United States)

    Fradkov, A. L.; Andrievsky, B.; Ananyevskiy, M.

    2014-04-01

    The recent results on nonlinear systems synchronization and control under communication constraints are applied to the remote state estimation and synchronization for a class of exogenously excited nonlinear Lurie systems. State estimation of the chain of diffusively coupled pendulums over the digital communication channel with limited capacity is experimentally studied. Advantage of the adaptive coding procedure under the conditions of the plant model uncertainty and irregular disturbances is shown. Quality of the estimation is evaluated by means of the experiments with the multi-pendulum set-up. Experimental study of master-slave synchronization over network (local network, wireless network) for the system with two cart-pendulums is presented.

  17. MMSE-NP-RISIC-Based Channel Equalization for MIMO-SC-FDE Troposcatter Communication Systems

    Directory of Open Access Journals (Sweden)

    Zedong Xie

    2016-01-01

    Full Text Available The impact of intersymbol interference (ISI on single-carrier frequency-domain equalization with multiple input multiple output (MIMO-SC-FDE troposcatter communication systems is severe. Most of the channel equalization methods fail to solve it completely. In this paper, given the disadvantages of the noise-predictive (NP MMSE-based and the residual intersymbol interference cancellation (RISIC equalization in the single input single output (SISO system, we focus on the combination of both equalization schemes mentioned above. After extending both of them into MIMO system for the first time, we introduce a novel MMSE-NP-RISIC equalization method for MIMO-SC-FDE troposcatter communication systems. Analysis and simulation results validate the performance of the proposed method in time-varying frequency-selective troposcatter channel at an acceptable computational complexity cost.

  18. Performance Analysis of Free-Space Optical Communication Systems With Multiuser Diversity Over Atmospheric Turbulence Channels

    KAUST Repository

    Yang, Liang

    2014-04-01

    Free-space optical (FSO) communication has become a cost-effective method to provide high data rates. However, the turbulence-induced fading limits its application to short-range applications. To address this, we propose a multiuser diversity (MD) FSO scheme in which the Nth best user is selected and the channel fluctuations can be effectively exploited to produce a selection diversity gain. More specifically, we first present the statistics analysis for the considered system over both weak and strong atmospheric turbulence channels. Based on these statistics, the outage probability, bit-error rate performance, average capacity, diversity order, and coverage are analyzed. Results show that the diversity order for the gamma-gamma fading is N min{α, β}/2, where N is the number of users, and α and β are the channel fading parameters related to the effective atmospheric conditions of the link.

  19. Eavesdropping on the "Ping-Pong" Quantum Communication Protocol Freely in a Noise Channel

    OpenAIRE

    Deng, Fu-Guo; Li, Xi-Han; Li, Chun-Yan; Zhou, Ping; Zhou, Hong-Yu

    2005-01-01

    We introduce an attack scheme for eavesdropping the ping-pong quantum communication protocol proposed by Bostr$\\ddot{o}$m and Felbinger [Phys. Rev. Lett. \\textbf{89}, 187902 (2002)] freely in a noise channel. The vicious eavesdropper, Eve, intercepts and measures the travel photon transmitted between the sender and the receiver. Then she replaces the quantum signal with a multi-photon signal in a same state, and measures the photons return with the measuring basis with which Eve prepares the ...

  20. Influence of the Communication Channel on the Forms of Impoliteness in Company-Customer Interactions

    OpenAIRE

    Schwab, Pierre-Nicolas; Rosier, Laurence

    2015-01-01

    The present study aims to examine verbal violence in companies’ answers sent in response to customers’ complaints through two different channels: online (on a public forum) vs. offline (by postal mail). We draw on a recent body of marketing literature pertaining to employees’ dysfunctional behaviors, as well as on conceptualizations of impoliteness, to analyze which role the communication method plays on the forms of impoliteness taken in those interactions.The online dataset of impolite answ...

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

    Science.gov (United States)

    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).

  2. Performance Limits of Energy Harvesting Communications under Imperfect Channel State Information

    KAUST Repository

    Zenaidi, Mohamed Ridah

    2015-01-07

    In energy harvesting communications, the transmitters have to adapt transmission to availability of energy harvested during the course of communication. The performance of the transmission depends on the channel conditions which vary randomly due to mobility and environmental changes. In this work, we consider the problem of power allocation taking into account the energy arrivals over time and the degree of channel state information (CSI) available at the transmitter, in order to maximize the throughput. In this work, the CSI at the transmitter is not perfect and may include estimation errors. We solve this problem with respect to the causality and energy storage constraints. We determine the optimal offline policy in the case where the channel is assumed to be perfectly known at the receiver. Different cases of CSI availability are studied for the transmitter. We obtain the power policy when the transmitter has either perfect CSI or no CSI. We also investigate of utmost interest the case of fading channels with imperfect CSI. Furthermore, we analyze the asymptotic average throughput in a system where the average recharge rate goes asymptotically to zero and when it is very high.

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

    Science.gov (United States)

    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.

  4. Mothers "Google It Up:" Extending Communication Channel Behavior in Diffusion of Innovations Theory.

    Science.gov (United States)

    Sundstrom, Beth

    2016-01-01

    This study employed qualitative methods, conducting 44 in-depth interviews with biological mothers of newborns to understand women's perceptions and use of new media, mass media, and interpersonal communication channels in relation to health issues. Findings contribute to theoretical and practical understandings of the role of communication channels in diffusion of innovations theory. In particular, this study provides a foundation for the use of qualitative research to advance applications of diffusion of innovations theory. Results suggest that participants resisted mass media portrayals of women's health. When faced with a health question, participants uniformly started with the Internet to "Google it up." Findings suggest new media comprise a new communication channel with new rules, serving the functions of both personal and impersonal influence. In particular, pregnancy and the postpartum period emerged as a time when campaign planners can access women in new ways online. As a result, campaign planners could benefit from introducing new ideas online and capitalizing on the strength of weak ties favored in new media. Results expand the innovativeness/needs paradox in diffusion of innovations theory by elaborating on the role of new media to reach underserved populations. These findings provide an opportunity to better understand patient information seeking through the lens of diffusion of innovations theory.

  5. Random matrix theory of multi-antenna communications: the Ricean channel

    International Nuclear Information System (INIS)

    Moustakas, Aris L; Simon, Steven H

    2005-01-01

    The use of multi-antenna arrays in wireless communications through disordered media promises huge increases in the information transmission rate. It is therefore important to analyse the information capacity of such systems in realistic situations of microwave transmission, where the statistics of the transmission amplitudes (channel) may be coloured. Here, we present an approach that provides analytic expressions for the statistics, i.e. the moments of the distribution, of the mutual information for general Gaussian channel statistics. The mathematical method applies tools developed originally in the context of coherent wave propagation in disordered media, such as random matrix theory and replicas. Although it is valid formally for large antenna numbers, this approach produces extremely accurate results even for arrays with as few as two antennas. We also develop a method to analytically optimize over the input signal distribution, which enables us to calculate analytic capacities when the transmitter has knowledge of the statistics of the channel. The emphasis of this paper is on elucidating the novel mathematical methods used. We do this by analysing a specific case when the channel matrix is a complex Gaussian with arbitrary mean and unit covariance, which is usually called the Ricean channel

  6. Performance Limits of Online Energy Harvesting Communications with Noisy Channel State Information at the Transmitter

    KAUST Repository

    Zenaidi, Mohamed Ridha

    2017-03-01

    In energy harvesting communications, the transceivers have to adjust the data transmission to the energy scavenged during the course of communication. The performance of the transmission depends on the channel conditions which vary randomly due to mobility and environmental changes. In this paper, we consider the problem of power allocation taking into account the energy arrivals over time and the quality of channel state information (CSI) measured at the transmitter, in order to maximize the throughput. Differently from previous work, we focus on energy harvesting communications where the CSI at the transmitter is not perfect and may include estimation errors. In the present paper, we introduce a Markov process that models the energy arrival process. Indeed, we solve the throughput maximization problem with respect to energy harvesting constraints. We show that the optimal online power policy can be found using dynamic programming. Furthermore, we study the asymptotic behavior of the communication system at low and high average recharge rate (ARR) regime. Selected numerical results are provided to support our analysis.

  7. DEVICE FOR BINARY DATA TRANSMITTING AND RECEIVING OVER A FIBEROPTIC COMMUNICATION CHANNEL

    Directory of Open Access Journals (Sweden)

    A. M. Timofeev

    2018-01-01

    Full Text Available When transferring data over optical fiber communication channels, it is required to provide data security and the authenticity of their source. To limit the access to the data for a third party, there can be applied quantum-cryptographical systems which are supposed to transfer every data bit by means of low power optical signals containing radiation photons the number of which could be in the range from 10 to 1, however, are far from being perfect and suffer from shortcomings, the main of which being a large number of errors due to the depolarization effect of optical radiation. The aim of this work was, therefore, to create device for sending and receiving confidential data which could provide complete security of transferred data, inherent to quantum-cryptographical communication systems at the same time could have a low number of such errors.A device for quantum-cryptographic communication system with a photon counter applied as a receiving module has been proposed. The possibility to use silicon avalanche photodetectors operating in the photon counting mode for confidential information transmission systems and defining authenticity of the source of transmitted information has been shown.I develop modern optical fiber communication system incorporating avalanche photodetector photon counter as a receiving module, that allow to detect unauthorized access to information and violation of its integrity and speed up the exchange of information in comparison with well-known quantum-cryptographical communication systems.

  8. Energy Efficient and Performance Analysis of Multihop Wireless Communication Over Nakagami-m Fading Channel

    KAUST Repository

    Randrianantenaina, Itsikiantsoa

    2015-06-01

    The concept of multihop communications (where the source communicates with the destination via many intermediate nodes) has been revisited and adapted to mitigate wireless channel impairments and ensure broader coverage. It has been shown in the literature that, in addition to extending coverage, overcoming shadowing and reducing the transmit power, multihop communications can increase the capacity of the network at a low additional cost. On the other hand, the problem of energy efficiency is one of the current biggest challenges towards green radio communications. Morevover, electromagnetic radiation is at its limit in many contexts, while for battery-powered devices, transmit and circuit energy consumption has to be minimized for better battery lifetime and performance. In this work, the performance of multihop communication over Nakagami-m fading is investigated for both cases without and with diversity combining. Closed form expressions of the average ergodic capacity are derived for each of these cases. Then, an expression of the outage probability is obtained using the inverse of Laplace transform and the average bit error rate is bounded using the Moment-Generating-Function approach. The energy efficiency is analyzed using the "consumption factor" as a metric, and it is derived in closed-form. And based on the obtained expressions, we propose a power allocation strategy maximizing this consumption factor.

  9. Insights into the Dialogic Communication on the ‘Debating Europe’ Internet Channels

    Directory of Open Access Journals (Sweden)

    Alexandra Bardan

    2017-03-01

    Full Text Available This article aims to provide an overview of the online interaction of the ‘Debating Europe’ platform using the theoretical framework of dialogic communication. A brief historical approach of the notion “Web 2.0” further informs about the functions of the ‘Debating Europe’ platform and its mission statement. Related work opens an interrogation on the ‘Debating Europe’ platform as a virtual space meant to connect European citizens and politicians in online debates concerning EU matters. The empirical study regards the use of dialogic principles on the ‘Debating Europe’ platform, focusing on a cross comparison of its three Internet channels: the website, the Facebook page and the Twitter account. The results indicate the website as the main dialogic channel, while Facebook and Twitter fulfill mainly information dissemination purposes.

  10. Cooperative jamming power control to enhance secrecy communications of AF Relaying systems for Rayleigh fading channel

    KAUST Repository

    Park, Kihong

    2012-09-01

    In this paper, we investigate secrecy communications in two-hop wireless relaying networks which consist of one source, one amplify-and-forward (AF) relay, one legitimate destination, and one eavesdropper. To prevent the eavesdropper from intercepting the source message, we make the destination send the intended noise to the AF relay during the first phase. This is referred to as cooperative jamming. According to the channel information at the destination, we address two types of jamming power allocation; (i) rate-optimal power allocation and (ii) outage-optimal power allocation. More specifically, without the instantaneous channel knowledge for the eavesdropper side, the outage probability of the secrecy rate is minimized with respect to the intended noise power level. We show that the outage-optimal allocation gives almost the same outage probability as the rateoptimal one. In addition, the jamming power consumption can be significantly reduced compared to the fixed and rate-optimal power allocation methods. © 2012 IEEE.

  11. On the Performance Analysis of Digital Communications over Weibull-Gamma Channels

    KAUST Repository

    Ansari, Imran Shafique

    2015-05-01

    In this work, the performance analysis of digital communications over a composite Weibull-Gamma (WG) multipath-fading and shadowing channel is presented wherein WG distribution is appropriate for modeling fading environments when multipath is superimposed on shadowing. More specifically, in this work, exact closed-form expressions are derived for the probability density function, the cumulative distribution function, the moment generating function, and the moments of a composite WG channel. Capitalizing on these results, new exact closed-form expressions are offered for the outage probability, the higher- order amount of fading, the average error rate for binary and M-ary modulation schemes, and the ergodic capacity under various types of transmission policies, mostly in terms of Meijer\\'s G functions. These new analytical results were also verified via computer-based Monte-Carlo simulation results. © 2015 IEEE.

  12. On the Performance Analysis of Digital Communications over Weibull-Gamma Channels

    KAUST Repository

    Ansari, Imran Shafique; Alouini, Mohamed-Slim

    2015-01-01

    In this work, the performance analysis of digital communications over a composite Weibull-Gamma (WG) multipath-fading and shadowing channel is presented wherein WG distribution is appropriate for modeling fading environments when multipath is superimposed on shadowing. More specifically, in this work, exact closed-form expressions are derived for the probability density function, the cumulative distribution function, the moment generating function, and the moments of a composite WG channel. Capitalizing on these results, new exact closed-form expressions are offered for the outage probability, the higher- order amount of fading, the average error rate for binary and M-ary modulation schemes, and the ergodic capacity under various types of transmission policies, mostly in terms of Meijer's G functions. These new analytical results were also verified via computer-based Monte-Carlo simulation results. © 2015 IEEE.

  13. Ultrasonic Digital Communication System for a Steel Wall Multipath Channel: Methods and Results

    Energy Technology Data Exchange (ETDEWEB)

    Murphy, Timothy L. [Rensselaer Polytechnic Inst., Troy, NY (United States)

    2005-12-01

    As of the development of this thesis, no commercially available products have been identified for the digital communication of instrumented data across a thick ({approx} 6 n.) steel wall using ultrasound. The specific goal of the current research is to investigate the application of methods for digital communication of instrumented data (i.e., temperature, voltage, etc.) across the wall of a steel pressure vessel. The acoustic transmission of data using ultrasonic transducers prevents the need to breach the wall of such a pressure vessel which could ultimately affect its safety or lifespan, or void the homogeneity of an experiment under test. Actual digital communication paradigms are introduced and implemented for the successful dissemination of data across such a wall utilizing solely an acoustic ultrasonic link. The first, dubbed the ''single-hop'' configuration, can communicate bursts of digital data one-way across the wall using the Differential Binary Phase-Shift Keying (DBPSK) modulation technique as fast as 500 bps. The second, dubbed the ''double-hop'' configuration, transmits a carrier into the vessel, modulates it, and retransmits it externally. Using a pulsed carrier with Pulse Amplitude Modulation (PAM), this technique can communicate digital data as fast as 500 bps. Using a CW carrier, Least Mean-Squared (LMS) adaptive interference suppression, and DBPSK, this method can communicate data as fast as 5 kbps. A third technique, dubbed the ''reflected-power'' configuration, communicates digital data by modulating a pulsed carrier by varying the acoustic impedance at the internal transducer-wall interface. The paradigms of the latter two configurations are believed to be unique. All modulation methods are based on the premise that the wall cannot be breached in any way and can therefore be viably implemented with power delivered wirelessly through the acoustic channel using ultrasound. Methods

  14. An Off-Grid Turbo Channel Estimation Algorithm for Millimeter Wave Communications

    Directory of Open Access Journals (Sweden)

    Lingyi Han

    2016-09-01

    Full Text Available The bandwidth shortage has motivated the exploration of the millimeter wave (mmWave frequency spectrum for future communication networks. To compensate for the severe propagation attenuation in the mmWave band, massive antenna arrays can be adopted at both the transmitter and receiver to provide large array gains via directional beamforming. To achieve such array gains, channel estimation (CE with high resolution and low latency is of great importance for mmWave communications. However, classic super-resolution subspace CE methods such as multiple signal classification (MUSIC and estimation of signal parameters via rotation invariant technique (ESPRIT cannot be applied here due to RF chain constraints. In this paper, an enhanced CE algorithm is developed for the off-grid problem when quantizing the angles of mmWave channel in the spatial domain where off-grid problem refers to the scenario that angles do not lie on the quantization grids with high probability, and it results in power leakage and severe reduction of the CE performance. A new model is first proposed to formulate the off-grid problem. The new model divides the continuously-distributed angle into a quantized discrete grid part, referred to as the integral grid angle, and an offset part, termed fractional off-grid angle. Accordingly, an iterative off-grid turbo CE (IOTCE algorithm is proposed to renew and upgrade the CE between the integral grid part and the fractional off-grid part under the Turbo principle. By fully exploiting the sparse structure of mmWave channels, the integral grid part is estimated by a soft-decoding based compressed sensing (CS method called improved turbo compressed channel sensing (ITCCS. It iteratively updates the soft information between the linear minimum mean square error (LMMSE estimator and the sparsity combiner. Monte Carlo simulations are presented to evaluate the performance of the proposed method, and the results show that it enhances the angle

  15. Electronic Communication Channel Use and Health Information Source Preferences Among Latinos in Northern Manhattan.

    Science.gov (United States)

    Hillyer, Grace Clarke; Schmitt, Karen M; Lizardo, Maria; Reyes, Andria; Bazan, Mercedes; Alvarez, Maria C; Sandoval, Rossy; Abdul, Kazeem; Orjuela, Manuela A

    2017-04-01

    Understanding key health concepts is crucial to participation in Precision Medicine initiatives. In order to assess methods to develop and disseminate a curriculum to educate community members in Northern Manhattan about Precision Medicine, clients from a local community-based organization were interviewed during 2014-2015. Health literacy, acculturation, use of Internet, email, and text messaging, and health information sources were assessed. Associations between age and outcomes were evaluated; multivariable analysis used to examine the relationship between participant characteristics and sources of health information. Of 497 interviewed, 29.4 % had inadequate health literacy and 53.6 % had access to the Internet, 43.9 % to email, and 45.3 % to text messaging. Having adequate health literacy was associated with seeking information from a healthcare professional (OR 2.59, 95 % CI 1.54-4.35) and from the Internet (OR 3.15, 95 % CI 1.97-5.04); having ≤ grade school education (OR 2.61, 95 % CI 1.32-5.17) also preferred information from their provider; persons >45 years (OR 0.29, 95 % CI 0.18-0.47) were less likely to use the Internet for health information and preferred printed media (OR 1.64, 95 % CI 1.07-2.50). Overall, electronic communication channel use was low and varied significantly by age with those ≤45 years more likely to utilize electronic channels. Preferred sources of health information also varied by age as well as by health literacy and educational level. This study demonstrates that to effectively communicate key Precision Medicine concepts, curriculum development for Latino community members of Northern Manhattan will require attention to health literacy, language preference and acculturation and incorporate more traditional communication channels for older community members.

  16. Language evolution and human-computer interaction

    Science.gov (United States)

    Grudin, Jonathan; Norman, Donald A.

    1991-01-01

    Many of the issues that confront designers of interactive computer systems also appear in natural language evolution. Natural languages and human-computer interfaces share as their primary mission the support of extended 'dialogues' between responsive entities. Because in each case one participant is a human being, some of the pressures operating on natural languages, causing them to evolve in order to better support such dialogue, also operate on human-computer 'languages' or interfaces. This does not necessarily push interfaces in the direction of natural language - since one entity in this dialogue is not a human, this is not to be expected. Nonetheless, by discerning where the pressures that guide natural language evolution also appear in human-computer interaction, we can contribute to the design of computer systems and obtain a new perspective on natural languages.

  17. Experimental realization of a highly secure chaos communication under strong channel noise

    International Nuclear Information System (INIS)

    Ye Weiping; Dai Qionglin; Wang Shihong; Lu Huaping; Kuang Jinyu; Zhao Zhenfeng; Zhu Xiangqing; Tang Guoning; Huang Ronghuai; Hu Gang

    2004-01-01

    A one-way coupled spatiotemporally chaotic map lattice is used to construct cryptosystem. With the combinatorial applications of both chaotic computations and conventional algebraic operations, our system has optimal cryptographic properties much better than the separative applications of known chaotic and conventional methods. We have realized experiments to practice duplex voice secure communications in realistic Wired Public Switched Telephone Network by applying our chaotic system and the system of Advanced Encryption Standard (AES), respectively, for cryptography. Our system can work stably against strong channel noise when AES fails to work

  18. Experimental realization of a highly secure chaos communication under strong channel noise

    Science.gov (United States)

    Ye, Weiping; Dai, Qionglin; Wang, Shihong; Lu, Huaping; Kuang, Jinyu; Zhao, Zhenfeng; Zhu, Xiangqing; Tang, Guoning; Huang, Ronghuai; Hu, Gang

    2004-09-01

    A one-way coupled spatiotemporally chaotic map lattice is used to construct cryptosystem. With the combinatorial applications of both chaotic computations and conventional algebraic operations, our system has optimal cryptographic properties much better than the separative applications of known chaotic and conventional methods. We have realized experiments to practice duplex voice secure communications in realistic Wired Public Switched Telephone Network by applying our chaotic system and the system of Advanced Encryption Standard (AES), respectively, for cryptography. Our system can work stably against strong channel noise when AES fails to work.

  19. Space communication system for compressed data with a concatenated Reed-Solomon-Viterbi coding channel

    Science.gov (United States)

    Rice, R. F.; Hilbert, E. E. (Inventor)

    1976-01-01

    A space communication system incorporating a concatenated Reed Solomon Viterbi coding channel is discussed for transmitting compressed and uncompressed data from a spacecraft to a data processing center on Earth. Imaging (and other) data are first compressed into source blocks which are then coded by a Reed Solomon coder and interleaver, followed by a convolutional encoder. The received data is first decoded by a Viterbi decoder, followed by a Reed Solomon decoder and deinterleaver. The output of the latter is then decompressed, based on the compression criteria used in compressing the data in the spacecraft. The decompressed data is processed to reconstruct an approximation of the original data-producing condition or images.

  20. Bounds on the Capacity of ASK Molecular Communication Channels with ISI

    OpenAIRE

    Ghavami, Siavash; Adve, Raviraj; Lahouti, Farshad

    2015-01-01

    There are now several works on the use of the additive inverse Gaussian noise (AIGN) model for the random transit time in molecular communication~(MC) channels. The randomness invariably causes inter-symbol interference (ISI) in MC, an issue largely ignored or simplified. In this paper we derive an upper bound and two lower bounds for MC based on amplitude shift keying (ASK) in presence of ISI. The Blahut-Arimoto algorithm~(BAA) is modified to find the input distribution of transmitted symbol...

  1. The Model of Communication Channel in the 802.11b Standard Wireless Network

    Directory of Open Access Journals (Sweden)

    Zdenek Nemec

    2008-01-01

    Full Text Available The paper deals with software modelling of a communication channel in the 802.11b standard wireless network physical layer. A computer model of signal processing was created to verify possibility of the proposal of localisation system. Functionality of the signal generation and processing model was verified by the Spectrum Analyzer. Simulations run inSimulink/Matlab SW. The Simulink is used for the signal processor model and a pure Matlab software is used for mathematical evaluations of data processor model and for determination of initial conditions.

  2. Frequency and spatial correlation functions in a fading communication channel through the ionosphere

    International Nuclear Information System (INIS)

    Liu, C.H.; Yeh, K.C.

    1975-01-01

    Equations for the two-frequency two-position mutual coherence functions are derived under the usual parabolic and Markov approximations. These equations are then solved numerically. It is shown that the mutual coherence functions occur naturally in the study of pulse distortion through a random communication channel and in the investigation of signal correlations. Contour plots of correlation functions show the possibility of having equal values at two frequency separations for a given spatial separation. This behavior is explainable in terms of overlapping Fresnel zones

  3. Round-Trip Delay Estimation in OPC UA Server-Client Communication Channel

    OpenAIRE

    Nakutis, Zilvinas; Deksnys, Vytautas; Jarusevicius, Ignas; Dambrauskas, Vilius; Cincikas, Gediminas; Kriauceliunas, Alenas

    2017-01-01

    In this paper an estimation of round-trip delay (RTD) in OPC UA server-client channel was investigated in various data communication networks including Ethernet, WiFi, and 3G. Testing was carried out using the developed IoT gateway device running OPC UA server and remote computer running OPC UA client. The server and the client machines were configured to operate in Virtual Private Network powered by OpenVPN. Experimental analysis revealed that RTD values are distributed in the wide range exh...

  4. Fault-tolerant controlled quantum secure direct communication over a collective quantum noise channel

    International Nuclear Information System (INIS)

    Yang, Chun-Wei; Hwang, Tzonelih; Tsai, Chia-Wei

    2014-01-01

    This work proposes controlled quantum secure direct communication (CQSDC) over an ideal channel. Based on the proposed CQSDC, two fault-tolerant CQSDC protocols that are robust under two kinds of collective noises, collective-dephasing noise and collective-rotation noise, respectively, are constructed. Due to the use of quantum entanglement of the Bell state (or logical Bell state) as well as dense coding, the proposed protocols provide easier implementation as well as better qubit efficiency than other CQSDC protocols. Furthermore, the proposed protocols are also free from correlation-elicitation attack and other well-known attacks. (paper)

  5. INSTITUTIONAL LOBBYING IN BRAZIL: A COMMUNICATION CHANNEL BETWEEN THE STATE AND THE CIVIL SOCIETY?

    Directory of Open Access Journals (Sweden)

    Andréa Cristina de Jesus Oliveira

    2007-12-01

    Full Text Available n this article it is examined the structure, the organization and the action of institutional lobbying in Brazilian Congress. Tthe institutional lobbying refers to the performance of the corporative or institutional departments of private companies devoted to the relationships with the different spheres and government levels. An important attribute of the corporative or institutional departments is the development of a communication channel with the State, trying to assist them with ideas and initiatives that can provide solutions for their problems and also to present the positions of the company.

  6. Adoption of ICT in Science Education: A Case Study of Communication Channels in a Teachers' Professional Development Project

    Science.gov (United States)

    Juuti, Kalle; Lavonen, Jari; Aksela, Maija; Meisalo, Veijo

    2009-01-01

    This paper analyses the use of various communication channels in science teachers' professional development project aiming to develop versatile uses for ICT (Information and Communication Technologies) in science teaching. A teacher network was created specifically for this project, and the researchers facilitated three forms of communication…

  7. Bandwidth-Efficient Communication through 225 MHz Ka-band Relay Satellite Channel

    Science.gov (United States)

    Downey, Joseph; Downey, James; Reinhart, Richard C.; Evans, Michael Alan; Mortensen, Dale John

    2016-01-01

    The communications and navigation space infrastructure of the National Aeronautics and Space Administration (NASA) consists of a constellation of relay satellites (called Tracking and Data Relay Satellites (TDRS)) and a global set of ground stations to receive and deliver data to researchers around the world from mission spacecraft throughout the solar system. Planning is underway to enhance and transform the infrastructure over the coming decade. Key to the upgrade will be the simultaneous and efficient use of relay transponders to minimize cost and operations while supporting science and exploration spacecraft. Efficient use of transponders necessitates bandwidth efficient communications to best use and maximize data throughput within the allocated spectrum. Experiments conducted with NASA's Space Communication and Navigation (SCaN) Testbed on the International Space Station provides a unique opportunity to evaluate advanced communication techniques, such as bandwidth-efficient modulations, in an operational flight system. Demonstrations of these new techniques in realistic flight conditions provides critical experience and reduces the risk of using these techniques in future missions. Efficient use of spectrum is enabled by using high-order modulations coupled with efficient forward error correction codes. This paper presents a high-rate, bandwidth-efficient waveform operating over the 225 MHz Ka-band service of the TDRS System (TDRSS). The testing explores the application of Gaussian Minimum Shift Keying (GMSK), 248-phase shift keying (PSK) and 1632- amplitude PSK (APSK) providing over three bits-per-second-per-Hertz (3 bsHz) modulation combined with various LDPC encoding rates to maximize throughput. With a symbol rate of 200 Mbaud, coded data rates of 1000 Mbps were tested in the laboratory and up to 800 Mbps over the TDRS 225 MHz channel. This paper will present on the high-rate waveform design, channel characteristics, performance results, compensation

  8. Bandwidth-Efficient Communication through 225 MHz Ka-band Relay Satellite Channel

    Science.gov (United States)

    Downey, Joseph A.; Downey, James M.; Reinhart, Richard C.; Evans, Michael A.; Mortensen, Dale J.

    2016-01-01

    The communications and navigation space infrastructure of the National Aeronautics and Space Administration (NASA) consists of a constellation of relay satellites (called Tracking and Data Relay Satellites (TDRS)) and a global set of ground stations to receive and deliver data to researchers around the world from mission spacecraft throughout the solar system. Planning is underway to enhance and transform the infrastructure over the coming decade. Key to the upgrade will be the simultaneous and efficient use of relay transponders to minimize cost and operations while supporting science and exploration spacecraft. Efficient use of transponders necessitates bandwidth efficient communications to best use and maximize data throughput within the allocated spectrum. Experiments conducted with NASA's Space Communication and Navigation (SCaN) Testbed on the International Space Station provides a unique opportunity to evaluate advanced communication techniques, such as bandwidth-efficient modulations, in an operational flight system. Demonstrations of these new techniques in realistic flight conditions provides critical experience and reduces the risk of using these techniques in future missions. Efficient use of spectrum is enabled by using high-order modulations coupled with efficient forward error correction codes. This paper presents a high-rate, bandwidth-efficient waveform operating over the 225 MHz Ka-band service of the TDRS System (TDRSS). The testing explores the application of Gaussian Minimum Shift Keying (GMSK), 2/4/8-phase shift keying (PSK) and 16/32- amplitude PSK (APSK) providing over three bits-per-second-per-Hertz (3 b/s/Hz) modulation combined with various LDPC encoding rates to maximize through- put. With a symbol rate of 200 M-band, coded data rates of 1000 Mbps were tested in the laboratory and up to 800 Mbps over the TDRS 225 MHz channel. This paper will present on the high-rate waveform design, channel characteristics, performance results

  9. Multi-step EMG Classification Algorithm for Human-Computer Interaction

    Science.gov (United States)

    Ren, Peng; Barreto, Armando; Adjouadi, Malek

    A three-electrode human-computer interaction system, based on digital processing of the Electromyogram (EMG) signal, is presented. This system can effectively help disabled individuals paralyzed from the neck down to interact with computers or communicate with people through computers using point-and-click graphic interfaces. The three electrodes are placed on the right frontalis, the left temporalis and the right temporalis muscles in the head, respectively. The signal processing algorithm used translates the EMG signals during five kinds of facial movements (left jaw clenching, right jaw clenching, eyebrows up, eyebrows down, simultaneous left & right jaw clenching) into five corresponding types of cursor movements (left, right, up, down and left-click), to provide basic mouse control. The classification strategy is based on three principles: the EMG energy of one channel is typically larger than the others during one specific muscle contraction; the spectral characteristics of the EMG signals produced by the frontalis and temporalis muscles during different movements are different; the EMG signals from adjacent channels typically have correlated energy profiles. The algorithm is evaluated on 20 pre-recorded EMG signal sets, using Matlab simulations. The results show that this method provides improvements and is more robust than other previous approaches.

  10. Performance analysis of MIMO wireless optical communication system with Q-ary PPM over correlated log-normal fading channel

    Science.gov (United States)

    Wang, Huiqin; Wang, Xue; Lynette, Kibe; Cao, Minghua

    2018-06-01

    The performance of multiple-input multiple-output wireless optical communication systems that adopt Q-ary pulse position modulation over spatial correlated log-normal fading channel is analyzed in terms of its un-coded bit error rate and ergodic channel capacity. The analysis is based on the Wilkinson's method which approximates the distribution of a sum of correlated log-normal random variables to a log-normal random variable. The analytical and simulation results corroborate the increment of correlation coefficients among sub-channels lead to system performance degradation. Moreover, the receiver diversity has better performance in resistance of spatial correlation caused channel fading.

  11. Modeling multimodal human-computer interaction

    NARCIS (Netherlands)

    Obrenovic, Z.; Starcevic, D.

    2004-01-01

    Incorporating the well-known Unified Modeling Language into a generic modeling framework makes research on multimodal human-computer interaction accessible to a wide range off software engineers. Multimodal interaction is part of everyday human discourse: We speak, move, gesture, and shift our gaze

  12. Applying Human Computation Methods to Information Science

    Science.gov (United States)

    Harris, Christopher Glenn

    2013-01-01

    Human Computation methods such as crowdsourcing and games with a purpose (GWAP) have each recently drawn considerable attention for their ability to synergize the strengths of people and technology to accomplish tasks that are challenging for either to do well alone. Despite this increased attention, much of this transformation has been focused on…

  13. The Model of Coordination of Communication Channels for Small Tourist Communities

    Directory of Open Access Journals (Sweden)

    Jelena VASKOVIĆ

    2013-12-01

    Full Text Available By including e-business, small tourist communities were allowed, apart from their classic offers, to appear on the global market, but that caused the need for automation and coordination of booking capacity tasks. Advertising and booking in these communities are performed by a conventional agency arrangement, the Internet, mobile services or by tourists themselves upon their arrival in the local community where they can reserve the accommodation. The possibility of booking accommodation capacities in many ways creates additional benefits for considerable usage of excess capacity, but as a side effect there is a problem of coordination of communication channels in order to avoid double-booking. On the other hand, the local administration has a problem with the registration and the payment of the tourist tax, particularly if the tourists do not stay long. With the automation and coordination of communication channels, conflicts can be completely avoided, and the reservation system informs all interested parties and reports to the local administration.

  14. Threshold-based detection for amplify-and-forward cooperative communication systems with channel estimation error

    KAUST Repository

    Abuzaid, Abdulrahman I.

    2014-09-01

    Efficient receiver designs for cooperative communication systems are becoming increasingly important. In previous work, cooperative networks communicated with the use of $L$ relays. As the receiver is constrained, it can only process $U$ out of $L$ relays. Channel shortening and reduced-rank techniques were employed to design the preprocessing matrix. In this paper, a receiver structure is proposed which combines the joint iterative optimization (JIO) algorithm and our proposed threshold selection criteria. This receiver structure assists in determining the optimal $U-{opt}$. Furthermore, this receiver provides the freedom to choose $U ≤ U-{opt}$ for each frame depending upon the tolerable difference allowed for mean square error (MSE). Our study and simulation results show that by choosing an appropriate threshold, it is possible to gain in terms of complexity savings without affecting the BER performance of the system. Furthermore, in this paper the effect of channel estimation errors is investigated on the MSE performance of the amplify-and-forward (AF) cooperative relaying system.

  15. A Novel Wearable Forehead EOG Measurement System for Human Computer Interfaces.

    Science.gov (United States)

    Heo, Jeong; Yoon, Heenam; Park, Kwang Suk

    2017-06-23

    Amyotrophic lateral sclerosis (ALS) patients whose voluntary muscles are paralyzed commonly communicate with the outside world using eye movement. There have been many efforts to support this method of communication by tracking or detecting eye movement. An electrooculogram (EOG), an electro-physiological signal, is generated by eye movements and can be measured with electrodes placed around the eye. In this study, we proposed a new practical electrode position on the forehead to measure EOG signals, and we developed a wearable forehead EOG measurement system for use in Human Computer/Machine interfaces (HCIs/HMIs). Four electrodes, including the ground electrode, were placed on the forehead. The two channels were arranged vertically and horizontally, sharing a positive electrode. Additionally, a real-time eye movement classification algorithm was developed based on the characteristics of the forehead EOG. Three applications were employed to evaluate the proposed system: a virtual keyboard using a modified Bremen BCI speller and an automatic sequential row-column scanner, and a drivable power wheelchair. The mean typing speeds of the modified Bremen brain-computer interface (BCI) speller and automatic row-column scanner were 10.81 and 7.74 letters per minute, and the mean classification accuracies were 91.25% and 95.12%, respectively. In the power wheelchair demonstration, the user drove the wheelchair through an 8-shape course without collision with obstacles.

  16. The Influence of eHealth Literacy on Perceived Trust in Online Health Communication Channels and Sources.

    Science.gov (United States)

    Paige, Samantha R; Krieger, Janice L; Stellefson, Michael L

    2017-01-01

    Disparities in online health information accessibility are partially due to varying levels of eHealth literacy and perceived trust. This study examined the relationship between eHealth literacy and perceived trust in online health communication channels and sources among diverse sociodemographic groups. A stratified sample of Black/African Americans (n = 402) and Caucasians (n = 409) completed a Web-based survey that measured eHealth literacy and perceived trustworthiness of online health communication channels and information sources. eHealth literacy positively predicted perceived trust in online health communication channels and sources, but disparities existed by sociodemographic factors. Segmenting audiences according to eHealth literacy level provides a detailed understanding of how perceived trust in discrete online health communication channels and information sources varies among diverse audiences. Black/African Americans with low eHealth literacy had high perceived trust in YouTube and Twitter, whereas Black/African Americans with high eHealth literacy had high perceived trust in online government and religious organizations. Older adults with low eHealth literacy had high perceived trust in Facebook but low perceived trust in online support groups. Researchers and practitioners should consider the sociodemographics and eHealth literacy level of an intended audience when tailoring information through trustworthy online health communication channels and information sources.

  17. Study and Validation of Eavesdropping Scenarios over a Visible Light Communication Channel

    Science.gov (United States)

    Perez-Jimenez, Rafael

    2017-01-01

    The security and privacy provided by Visible Light Communication (VLC) technologies is an area that has been slightly addressed due to the misconception that, since light does not go through solid objects like walls, VLC-based communications cannot be eavesdropped on by outside observers. As an upcoming technology, VLC is expected to be used in multiple environments were, due to radio frequency RF overuse or limitations, RF solutions cannot or should not be employed. In this work, we study the eavesdropping characteristics of a VLC-based communication. To evaluate these concerns, a two-step process was followed. First, several simulations of a standardly used scenario were run. Later on, experimental tests were performed. Following those tests, the results of the simulations and the experimental tests were analyzed. The results of these simulations and tests seemed to indicate that VLC channels can be eavesdropped on without considerable difficulties. Furthermore, the results showed that sniffing attacks could be performed from areas outside the expected coverage of the VLC infrastructure. Finally, the use of the simulation such as the one implemented in this work to recognize places from which sniffing is possible helps determine the risk for eavesdropping that our VLC-based network has. PMID:29160800

  18. Study and Validation of Eavesdropping Scenarios over a Visible Light Communication Channel

    Directory of Open Access Journals (Sweden)

    Ignacio Marin-Garcia

    2017-11-01

    Full Text Available The security and privacy provided by Visible Light Communication (VLC technologies is an area that has been slightly addressed due to the misconception that, since light does not go through solid objects like walls, VLC-based communications cannot be eavesdropped on by outside observers. As an upcoming technology, VLC is expected to be used in multiple environments were, due to radio frequency RF overuse or limitations, RF solutions cannot or should not be employed. In this work, we study the eavesdropping characteristics of a VLC-based communication. To evaluate these concerns, a two-step process was followed. First, several simulations of a standardly used scenario were run. Later on, experimental tests were performed. Following those tests, the results of the simulations and the experimental tests were analyzed. The results of these simulations and tests seemed to indicate that VLC channels can be eavesdropped on without considerable difficulties. Furthermore, the results showed that sniffing attacks could be performed from areas outside the expected coverage of the VLC infrastructure. Finally, the use of the simulation such as the one implemented in this work to recognize places from which sniffing is possible helps determine the risk for eavesdropping that our VLC-based network has.

  19. THz-TDS Characterization of the Digital Communication Channels of the Atmosphere and the Enabled Applications

    Science.gov (United States)

    Yang, Yihong; Mandehgar, Mahboubeh; Grischkowsky, D.

    2015-02-01

    Our measurements and complete linear dispersion theory calculations of amplitude and phase show that it is possible to have seven high performance point-to-point, 10.7 Gb/s to 28.4 Gb/s, digital THz ground links in the atmosphere. At a RH 58% (10g/m3) and 20 °C including O2 absorption, and for an absorption loss of 10 dB, the seven links are: Channel 1: at 96 GHz, Bandwidth (BW) 30 GHz, 10.7 Gb/s for 17.5 km, Channel 2: at 144 GHz, BW 30 GHz, 12.0 Gb/s for 7.4 km, Channel 3: at 252 GHz, BW 50 GHz, 25.2 Gb/s for 2.5 km, Channel 4: at 342 GHz, BW 24 GHz, 11.4 Gb/s for 840 m, Channel 5: at 408 GHz, BW 30 GHz, 13.6 Gb/s for 440 m, Channel 6: at 672 GHz, BW 60 GHz, 22.6 Gb/s for 140 m, and Channel 7: at 852 GHz, BW 60 GHz, 28.4 Gb/s for 120 m. The enabled long-path THz links are discussed. Two applications are presented in detail, namely, a long-path 17.5 km THz ground-link operating at 96 GHz, BW 30 GHz, 10.7 Gb/s, and a GEO satellite link at 252 GHz, BW 50 GHz, 25.2 Gb/s. In addition, Channel 7 at 852 GHz is studied by calculated pulse propagation to understand the relationships between high bit-rates and propagation distance. It is shown that good digital transmission could be obtained with 852 GHz, BW 108 GHz, 56.8 Gb/s for a 160 m propagation distance in the atmosphere with RH 58% (10g/m3) and 20 °C. Good digital transmission could also be obtained with 852 GHz, BW 108 GHz, 71.0 Gb/s for 80 m. These results are discussed with respect to high bit-rate, short-path applications. These digital THz communication channels were determined together with a new measurement of the water vapor continuum absorption from 0.35 to 1 THz. The THz pulses propagate though a 137 m long humidity-controlled chamber and are measured by THz time-domain spectroscopy (THz-TDS). The average relative humidity along the entire THz path is precisely obtained by measuring the difference between transit times of the sample and reference THz pulses to an accuracy of 0.1 ps. Using the measured

  20. Internet as a new communication, retail and distribution channel for young consumers

    Directory of Open Access Journals (Sweden)

    Vatroslav Škare

    2006-12-01

    Full Text Available Marketing aspects of the Internet can be examined through a great number of researches on marketing practices conducted via the Internet. A number of authors consider the Internet as new marketplace (marketspace, where the exchange of both traditional and new values (i.e. digital products and services takes place. The Internet supports almost all aspects of a company’s business activities and can be applied with respect to all the elements of marketing mix. The subject of this paper is the role of adoption and use of the Internet as a new communication, retail and distribution channel for young consumers. The research was conducted in January 2006 and included 869 students from nine faculties at the University of Zagreb. Students represent an important marketing segment for Internet marketing activities since they are considered to be advanced users of the Internet. The relevance of students’ Internet adoption and use is determined by the following reasons: students are consumers; senior students will soon become young employed professionals with their own income (their spending will increase rapidly; in the near future, senior students will, to some extent, be decision makers on the implementation of business activities via the Internet. Research results show that students actively use the Internet, primarily as a communication channel. The student use of the Internet for purchasing tangible products is rare but their use of services via the Internet is considerable. Students find using the Internet to be a non-complex activity. There is no significant difference in the perception of complexity of the Internet usage among respondents with different computer and English language skills or with respect to their majoring fields (Arts, Biomedicine, Biotechnology, Engineering, Humanities, Natural and Social Sciences. A perception of the complexity of product purchase and service usage via the Internet is influenced by the experience that

  1. Communicating with parents of obese children: which channels are most effective?

    Science.gov (United States)

    Randle, Melanie; Okely, Anthony D; Dolnicar, Sara

    2017-04-01

    One of the strategies proven most successful in curbing rising rates of childhood obesity involves targeting parents as agents of change. Prior studies have focused on what messages to communicate, but few have investigated how they should be communicated. To identify the channels most effective for communicating with parents of overweight and obese children and understand whether their use of parenting information sources differs from others in the community. This study utilizes data from the Longitudinal Study of Australian Children (LSAC). Families were included if weight and height information was available for parents and children at three data collection points: Waves 1, 2 and 4 (collected 2004, 2006 and 2010, respectively, n = 5107). A priori and a posteriori segmentation methods identified groups of parents that were similar in the sources used to obtain information about parenting, and examined whether some segments were more likely to have obese children. Four segments were identified that differed in their information source use: the 'personal networks', 'books', 'official sources' and 'mixed approach' segments. The 'official sources' and 'mixed approach' segments were most likely to have obese children, and they used doctors, government/community organizations and friends to obtain information on parenting. These segments were also less educated and had lower employment. Messages are most likely to reach families with obese children if communicated through doctors, government publications and community organizations. Further, messages targeting social groupings of parents will leverage the power of advice from friends, which is another valuable information source for this group. © 2016 The Authors. Health Expectations Published by John Wiley & Sons Ltd.

  2. Proxemics in Human-Computer Interaction

    OpenAIRE

    Greenberg, Saul; Honbaek, Kasper; Quigley, Aaron; Reiterer, Harald; Rädle, Roman

    2014-01-01

    In 1966, anthropologist Edward Hall coined the term "proxemics." Proxemics is an area of study that identifies the culturally dependent ways in which people use interpersonal distance to understand and mediate their interactions with others. Recent research has demonstrated the use of proxemics in human-computer interaction (HCI) for supporting users' explicit and implicit interactions in a range of uses, including remote office collaboration, home entertainment, and games. One promise of pro...

  3. Human-Computer Interaction in Smart Environments

    Science.gov (United States)

    Paravati, Gianluca; Gatteschi, Valentina

    2015-01-01

    Here, we provide an overview of the content of the Special Issue on “Human-computer interaction in smart environments”. The aim of this Special Issue is to highlight technologies and solutions encompassing the use of mass-market sensors in current and emerging applications for interacting with Smart Environments. Selected papers address this topic by analyzing different interaction modalities, including hand/body gestures, face recognition, gaze/eye tracking, biosignal analysis, speech and activity recognition, and related issues.

  4. Measuring propagation delay over a coded serial communication channel using FPGAs

    International Nuclear Information System (INIS)

    Jansweijer, P.P.M.; Peek, H.Z.

    2011-01-01

    Measurement and control applications are increasingly using distributed system technologies. In such applications, which may be spread over large distances, it is often necessary to synchronize system timing and know with great precision the time offsets between parts of the system. Measuring the propagation delay over a coded serial communication channel using serializer/deserializer (SerDes) functionality in FPGAs is described. The propagation delay between transmitter and receiver is measured with a resolution of a single unit interval (i.e. a serial link running at 3.125 Gbps provides a 320 ps resolution). The technique has been demonstrated to work over 100 km fibre to verify the feasibility for application in the future KM3NeT telescope.

  5. Broadband Mm-Wave OFDM Communications in Doubly Selective Channel: Performance Evaluation Using Measured Mm-Wave Channel

    DEFF Research Database (Denmark)

    Chen, Xiaoming; Fan, Wei; Pedersen, Gert F.

    2018-01-01

    In this work, we evaluate the performance of the broadband millimeter-wave (mm-wave) OFDM system in the presence of phase noise (PN) of phase-locked loop based oscillator and delay spread of measured mm-wave channel. It is shown, using Akaike's information criterion, that the channel tap...... coefficients of the broadband mm-wave channel do not follow Gaussian distribution due to the broad bandwidth. It is also shown that, given a cyclic prefix (CP) length for a certain delay spread, an effective PN mitigation scheme enables a PN corrupted OFDM system to function with small subcarrier spacing and...

  6. Configurable Transmitter and Systolic Channel Estimator Architectures for Data-Dependent Superimposed Training Communications Systems

    Directory of Open Access Journals (Sweden)

    E. Romero-Aguirre

    2012-01-01

    Full Text Available In this paper, a configurable superimposed training (ST/data-dependent ST (DDST transmitter and architecture based on array processors (APs for DDST channel estimation are presented. Both architectures, designed under full-hardware paradigm, were described using Verilog HDL, targeted in Xilinx Virtex-5 and they were compared with existent approaches. The synthesis results showed a FPGA slice consumption of 1% for the transmitter and 3% for the estimator with 160 and 115 MHz operating frequencies, respectively. The signal-to-quantization-noise ratio (SQNR performance of the transmitter is about 82 dB to support 4/16/64-QAM modulation. A Monte Carlo simulation demonstrates that the mean square error (MSE of the channel estimator implemented in hardware is practically the same as the one obtained with the floating-point golden model. The high performance and reduced hardware of the proposed architectures lead to the conclusion that the DDST concept can be applied in current communications standards.

  7. Channel modeling and performance evaluation of FSO communication systems in fog

    KAUST Repository

    Esmail, Maged Abdullah

    2016-07-01

    Free space optical (FSO) communication has become more exciting during the last decade. It has unregulated spectrum with a huge capacity compared to its radio frequency (RF) counterpart. Although FSO has many applications that cover indoor and outdoor environments, its widespread is humped by weather effects. Fog is classified as an extreme weather impairment that may cause link drop. Foggy channel modeling and characterization is necessary to analyze the system performance. In this paper, we first address the statistical behavior of the foggy channel based on a set of literature experimental data and develop a probability distribution function (PDF) model for fog attenuation. We then exploit our PDF model to derive closed form expressions and evaluate the system performance theoretically and numerically, in terms of average signal-to-noise ratio (SNR), and outage probability. The results show that for 10-3 outage probability and 22 dBm transmitted power, the FSO system can work over 80 m, 160 m, 310 m, and 460 m link length under dense, thick, moderate, and light fog respectively. Increasing the transmitted power will have high impact when the fog density is low. However, under very dense fog, it has almost no effect. © 2016 IEEE.

  8. Channel modeling and performance evaluation of FSO communication systems in fog

    KAUST Repository

    Esmail, Maged Abdullah; Fathallah, Habib; Alouini, Mohamed-Slim

    2016-01-01

    Free space optical (FSO) communication has become more exciting during the last decade. It has unregulated spectrum with a huge capacity compared to its radio frequency (RF) counterpart. Although FSO has many applications that cover indoor and outdoor environments, its widespread is humped by weather effects. Fog is classified as an extreme weather impairment that may cause link drop. Foggy channel modeling and characterization is necessary to analyze the system performance. In this paper, we first address the statistical behavior of the foggy channel based on a set of literature experimental data and develop a probability distribution function (PDF) model for fog attenuation. We then exploit our PDF model to derive closed form expressions and evaluate the system performance theoretically and numerically, in terms of average signal-to-noise ratio (SNR), and outage probability. The results show that for 10-3 outage probability and 22 dBm transmitted power, the FSO system can work over 80 m, 160 m, 310 m, and 460 m link length under dense, thick, moderate, and light fog respectively. Increasing the transmitted power will have high impact when the fog density is low. However, under very dense fog, it has almost no effect. © 2016 IEEE.

  9. LDPC-coded MIMO optical communication over the atmospheric turbulence channel using Q-ary pulse-position modulation.

    Science.gov (United States)

    Djordjevic, Ivan B

    2007-08-06

    We describe a coded power-efficient transmission scheme based on repetition MIMO principle suitable for communication over the atmospheric turbulence channel, and determine its channel capacity. The proposed scheme employs the Q-ary pulse-position modulation. We further study how to approach the channel capacity limits using low-density parity-check (LDPC) codes. Component LDPC codes are designed using the concept of pairwise-balanced designs. Contrary to the several recent publications, bit-error rates and channel capacities are reported assuming non-ideal photodetection. The atmospheric turbulence channel is modeled using the Gamma-Gamma distribution function due to Al-Habash et al. Excellent bit-error rate performance improvement, over uncoded case, is found.

  10. Performance analysis of passive time reversal communication technique for multipath interference in shallow sea acoustic channel

    Science.gov (United States)

    Kida, Yukihiro; Shimura, Takuya; Deguchi, Mitsuyasu; Watanabe, Yoshitaka; Ochi, Hiroshi; Meguro, Koji

    2017-07-01

    In this study, the performance of passive time reversal (PTR) communication techniques in multipath rich underwater acoustic environments is investigated. It is recognized empirically and qualitatively that a large number of multipath arrivals could generally raise the demodulation result of PTR. However, the relationship between multipath and the demodulation result is hardly evaluated quantitatively. In this study, the efficiency of the PTR acoustic communication techniques for multipath interference cancelation was investigated quantitatively by applying a PTR-DFE (decision feed-back filter) scheme to a synthetic dataset of a horizontal underwater acoustic channel. Mainly, in this study, we focused on the relationship between the signal-to-interference ratio (SIR) of datasets and the output signal-to-noise ratio (OSNR) of demodulation results by a parametric study approach. As a result, a proportional relation between SIR and OSNR is confirmed in low-SNR datasets. It was also found that PTR has a performance limitation, that is OSNR converges to a typical value depending on the number of receivers. In conclusion, results indicate that PTR could utilize the multipath efficiently and also withstand the negative effects of multipath interference at a given limitation.

  11. Channel and delay estimation for base-station–based cooperative communications in frequency-selective fading channels

    Directory of Open Access Journals (Sweden)

    Hongjun Xu

    2011-07-01

    Full Text Available A channel and delay estimation algorithm for both positive and negative delay, based on the distributed Alamouti scheme, has been recently discussed for base-station–based asynchronous cooperative systems in frequency-flat fading channels. This paper extends the algorithm, the maximum likelihood estimator, to work in frequency-selective fading channels. The minimum mean square error (MMSE performance of channel estimation for both packet schemes and normal schemes is discussed in this paper. The symbol error rate (SER performance of equalisation and detection for both time-reversal space-time block code (STBC and single-carrier STBC is also discussed in this paper. The MMSE simulation results demonstrated the superior performance of the packet scheme over the normal scheme with an improvement in performance of up to 6 dB when feedback was used in the frequency-selective channel at a MSE of 3 x 10–2. The SER simulation results showed that, although both the normal and packet schemes achieved similar diversity orders, the packet scheme demonstrated a 1 dB coding gain over the normal scheme at a SER of 10–5. Finally, the SER simulations showed that the frequency-selective fading system outperformed the frequency-flat fading system.

  12. Broadband Mm-Wave OFDM Communications in Doubly Selective Channel: Performance Evaluation Using Measured Mm-Wave Channel

    DEFF Research Database (Denmark)

    Chen, Xiaoming; Fan, Wei; Pedersen, Gert F.

    2018-01-01

    coefficients of the broadband mm-wave channel do not follow Gaussian distribution due to the broad bandwidth. It is also shown that, given a cyclic prefix (CP) length for a certain delay spread, an effective PN mitigation scheme enables a PN corrupted OFDM system to function with small subcarrier spacing and......In this work, we evaluate the performance of the broadband millimeter-wave (mm-wave) OFDM system in the presence of phase noise (PN) of phase-locked loop based oscillator and delay spread of measured mm-wave channel. It is shown, using Akaike's information criterion, that the channel tap......, therefore, small CP overhead, with only slight degradation of the error rate performance....

  13. Using the amplitude variation of a reverberation chamber channel to predict the synchronization of a wireless digital communication test system

    NARCIS (Netherlands)

    Tanuhardja, Ray R.; Gonzalez, Luis A.; Wang, Chih-Ming; Young, William F.; Remley, Kate A.; Ladbury, John M.

    2015-01-01

    We discuss the use of a metric based on the amplitude variation of a channel in the signal bandwidth to predict whether or not a digital wireless communication test system receiver will be able to demodulate a test signal. This metric is compared to another method consisting of the correlation

  14. Validation of simulations of an underwater acoustic communication channel characterized by wind-generated surface waves and bubbles

    NARCIS (Netherlands)

    Dol, H.S.; Colin, M.E.G.D.; Ainlie, M.A.; Gerdes, F.; Schäfke, A.; Özkan Sertlekc, H.

    2013-01-01

    This paper shows that it is possible to simulate realistic shallow-water acoustic communication channels using available acoustic propagation models. Key factor is the incorporation of realistic time-dependent sea surface conditions, including both waves and bubbles due to wind.

  15. Enrichment of Human-Computer Interaction in Brain-Computer Interfaces via Virtual Environments

    Directory of Open Access Journals (Sweden)

    Alonso-Valerdi Luz María

    2017-01-01

    Full Text Available Tridimensional representations stimulate cognitive processes that are the core and foundation of human-computer interaction (HCI. Those cognitive processes take place while a user navigates and explores a virtual environment (VE and are mainly related to spatial memory storage, attention, and perception. VEs have many distinctive features (e.g., involvement, immersion, and presence that can significantly improve HCI in highly demanding and interactive systems such as brain-computer interfaces (BCI. BCI is as a nonmuscular communication channel that attempts to reestablish the interaction between an individual and his/her environment. Although BCI research started in the sixties, this technology is not efficient or reliable yet for everyone at any time. Over the past few years, researchers have argued that main BCI flaws could be associated with HCI issues. The evidence presented thus far shows that VEs can (1 set out working environmental conditions, (2 maximize the efficiency of BCI control panels, (3 implement navigation systems based not only on user intentions but also on user emotions, and (4 regulate user mental state to increase the differentiation between control and noncontrol modalities.

  16. Introduction to human-computer interaction

    CERN Document Server

    Booth, Paul

    2014-01-01

    Originally published in 1989 this title provided a comprehensive and authoritative introduction to the burgeoning discipline of human-computer interaction for students, academics, and those from industry who wished to know more about the subject. Assuming very little knowledge, the book provides an overview of the diverse research areas that were at the time only gradually building into a coherent and well-structured field. It aims to explain the underlying causes of the cognitive, social and organizational problems typically encountered when computer systems are introduced. It is clear and co

  17. Human-Computer Interaction in Smart Environments

    Directory of Open Access Journals (Sweden)

    Gianluca Paravati

    2015-08-01

    Full Text Available Here, we provide an overview of the content of the Special Issue on “Human-computer interaction in smart environments”. The aim of this Special Issue is to highlight technologies and solutions encompassing the use of mass-market sensors in current and emerging applications for interacting with Smart Environments. Selected papers address this topic by analyzing different interaction modalities, including hand/body gestures, face recognition, gaze/eye tracking, biosignal analysis, speech and activity recognition, and related issues.

  18. Fundamentals of human-computer interaction

    CERN Document Server

    Monk, Andrew F

    1985-01-01

    Fundamentals of Human-Computer Interaction aims to sensitize the systems designer to the problems faced by the user of an interactive system. The book grew out of a course entitled """"The User Interface: Human Factors for Computer-based Systems"""" which has been run annually at the University of York since 1981. This course has been attended primarily by systems managers from the computer industry. The book is organized into three parts. Part One focuses on the user as processor of information with studies on visual perception; extracting information from printed and electronically presented

  19. Experimental demonstration of OFDM/OQAM transmission with DFT-based channel estimation for visible laser light communications

    Science.gov (United States)

    He, Jing; Shi, Jin; Deng, Rui; Chen, Lin

    2017-08-01

    Recently, visible light communication (VLC) based on light-emitting diodes (LEDs) is considered as a candidate technology for fifth-generation (5G) communications, VLC is free of electromagnetic interference and it can simplify the integration of VLC into heterogeneous wireless networks. Due to the data rates of VLC system limited by the low pumping efficiency, small output power and narrow modulation bandwidth, visible laser light communication (VLLC) system with laser diode (LD) has paid more attention. In addition, orthogonal frequency division multiplexing/offset quadrature amplitude modulation (OFDM/OQAM) is currently attracting attention in optical communications. Due to the non-requirement of cyclic prefix (CP) and time-frequency domain well-localized pulse shapes, it can achieve high spectral efficiency. Moreover, OFDM/OQAM has lower out-of-band power leakage so that it increases the system robustness against inter-carrier interference (ICI) and frequency offset. In this paper, a Discrete Fourier Transform (DFT)-based channel estimation scheme combined with the interference approximation method (IAM) is proposed and experimentally demonstrated for VLLC OFDM/OQAM system. The performance of VLLC OFDM/OQAM system with and without DFT-based channel estimation is investigated. Moreover, the proposed DFT-based channel estimation scheme and the intra-symbol frequency-domain averaging (ISFA)-based method are also compared for the VLLC OFDM/OQAM system. The experimental results show that, the performance of EVM using the DFT-based channel estimation scheme is improved about 3dB compared with the conventional IAM method. In addition, the DFT-based channel estimation scheme can resist the channel noise effectively than that of the ISFA-based method.

  20. Communication channels to promote evidence-based practice: a survey of primary care clinicians to determine perceived effects.

    Science.gov (United States)

    Dadich, Ann; Hosseinzadeh, Hassan

    2016-08-11

    Research suggests that the channels through which evidence-based practices are communicated to healthcare professionals can shape the ways they engage with, and use, this information. For instance, there is evidence to suggest that information should be communicated via sources that are deemed to be credible, like government departments, professional bodies and peers. This article examines the contention that information should be communicated via credible sources. More specifically, the article examines the different communication channels through which primary care clinicians learnt of resources on evidence-based sexual healthcare - namely, clinical aides and online training programs. Furthermore, the article determines whether these communication channels influenced the perceived impact of the resources. Primary care clinicians in Australia (n = 413), notably General Practitioners (n = 214) and Practice Nurses (n = 217), were surveyed on the GP Project - a suite of resources to promote evidence-based sexual healthcare within primary care. Survey items pertained to the source of information about the resources (or communication channel), perceived usefulness of the resources, frequency of use, subsequent contact with the Sexual Health Infoline and a sexual health clinic, as well as the perceived impact of the resources. To determine the relationships between the different communication channels and the perceived impact of the resources, a one-way ANOVA using Tukey's post-hoc test, an independent sample t-test, a χ(2) test, and a Kruskal-Wallis H test were performed where appropriate. Of the respondents who were aware of the clinical aides (49.9%), the largest proportion became aware of these through an educational event or a colleague. Of those who were aware of the online training programs (36.9%), the largest proportion became aware of these through a professional body or government organisation, either directly or via their website. Although both resource

  1. Throughput increase of the covert communication channel organized by the stable steganography algorithm using spatial domain of the image

    Directory of Open Access Journals (Sweden)

    O.V. Kostyrka

    2016-09-01

    Full Text Available At the organization of a covert communication channel a number of requirements are imposed on used steganography algorithms among which one of the main are: resistance to attacks against the built-in message, reliability of perception of formed steganography message, significant throughput of a steganography communication channel. Aim: The aim of this research is to modify the steganography method, developed by the author earlier, which will allow to increase the throughput of the corresponding covert communication channel when saving resistance to attacks against the built-in message and perception reliability of the created steganography message, inherent to developed method. Materials and Methods: Modifications of a steganography method that is steady against attacks against the built-in message which is carrying out the inclusion and decoding of the sent (additional information in spatial domain of the image allowing to increase the throughput of the organized communication channel are offered. Use of spatial domain of the image allows to avoid accumulation of an additional computational error during the inclusion/decoding of additional information due to “transitions” from spatial domain of the image to the area of conversion and back that positively affects the efficiency of decoding. Such methods are considered as attacks against the built-in message: imposing of different noise on a steganography message, filtering, lossy compression of a ste-ganography message where the JPEG and JPEG2000 formats with different quality coefficients for saving of a steganography message are used. Results: It is shown that algorithmic implementations of the offered methods modifications remain steady against the perturbing influences, including considerable, provide reliability of perception of the created steganography message, increase the throughput of the created steganography communication channel in comparison with the algorithm implementing

  2. FEMALE SHOPPERS’ OUTLOOK OF FIRMS’ FAIRNESS IN MARKETING COMMUNICATIONS AND DISTRIBUTION CHANNELS

    Directory of Open Access Journals (Sweden)

    Pranav KUMAR

    2017-05-01

    Full Text Available Consumers often experience injustice from the businesses which ignore fairness aspects in their marketing activities which can range from improper promotional campaigns to distribution bias and so on. As such, it has been of immense importance for the researchers to explicitly examine the role of virtuous marketing practices in shaping attitude of consumers. Accordingly, by means of a survey based investigation conducted with urban female consumers, this study probes the attitude of shoppers towards businesses’ ethicality in their marketing activities. Results indicate that righteousness in marketing communications and fairness in distribution channels exhibit a positive relationship with the attitude of consumers which further impacts their intentions to peruse marketers’ ethicalities while developing plans to buy cosmetics products. Furthermore, in an ethical marketing context, subjective norms and perceived behavioral control also influence consumer intentions significantly. It is also discovered that consumer lifestyle facets reflected by religiosity and women’s role and perception exert no moderating influence over the attitude-intention link. Consequently, managers are recommended to take adequate measures towards ensuring that their promotional and distributive actions are seen by the consumers as fair, reasonable and virtuous.

  3. Outage Analysis of Train-to-Train Communication Model over Nakagami-m Channel in High-Speed Railway

    Directory of Open Access Journals (Sweden)

    Pengyu Liu

    2013-01-01

    Full Text Available This paper analyzes the end-to-end outage performance of high-speed-railway train-to-train communication model in high-speed railway over independent identical and nonidentical Nakagami-m channels. The train-to-train communication is inter-train communication without an aid of infrastructure (for base station. Source train uses trains on other rail tracks as relays to transmit signals to destination train on the same track. The mechanism of such communication among trains can be divided into three cases based on occurrence of possible-occurrence relay trains. We first present a new closed form for the sum of squared independent Nakagami-m variates and then derive an expression for the outage probability of the identical and non-identical Nakagami-m channels in three cases. In particular, the problem is improved by the proposed formulation that statistic for sum of squared Nakagami-m variates with identical m tends to be infinite. Numerical analysis indicates that the derived analytic results are reasonable and the outage performance is better over Nakagami-m channel in high-speed railway scenarios.

  4. Channel characterization for high-speed W-band wireless communication links

    DEFF Research Database (Denmark)

    Rommel, Simon; Cavalcante, Lucas Costa Pereira; Vegas Olmos, Juan José

    2015-01-01

    We present and discuss results from an experimental characterization of the W-band indoor wireless channel, including both large and small scale fading phenomena as well as corresponding channel parameters and their impact on system performance....

  5. In-service communication channel sensing based on reflectometry for TWDM-PON systems

    Science.gov (United States)

    Iida, Daisuke; Kuwano, Shigeru; Terada, Jun

    2014-05-01

    Many base stations are accommodated in TWDM-PON based mobile backhaul and fronthaul networks for future radio access, and failed connections in an optical network unit (ONU) wavelength channel severely degrade system performance. A cost effective in-service ONU wavelength channel monitor is essential to ensure proper system operation without failed connections. To address this issue we propose a reflectometry-based remote sensing method that provides wavelength channel information with the optical line terminal (OLT)-ONU distance. The method realizes real-time monitoring of ONU wavelength channels without signal quality degradation. Experimental results show it achieves wavelength channel distinction with high distance resolution.

  6. Protein translocation channel of mitochondrial inner membrane and matrix-exposed import motor communicate via two-domain coupling protein.

    Science.gov (United States)

    Banerjee, Rupa; Gladkova, Christina; Mapa, Koyeli; Witte, Gregor; Mokranjac, Dejana

    2015-12-29

    The majority of mitochondrial proteins are targeted to mitochondria by N-terminal presequences and use the TIM23 complex for their translocation across the mitochondrial inner membrane. During import, translocation through the channel in the inner membrane is coupled to the ATP-dependent action of an Hsp70-based import motor at the matrix face. How these two processes are coordinated remained unclear. We show here that the two domain structure of Tim44 plays a central role in this process. The N-terminal domain of Tim44 interacts with the components of the import motor, whereas its C-terminal domain interacts with the translocation channel and is in contact with translocating proteins. Our data suggest that the translocation channel and the import motor of the TIM23 complex communicate through rearrangements of the two domains of Tim44 that are stimulated by translocating proteins.

  7. Comparison of Digisonde and CDSS measurement for the monitoring of the existence of the Ionospheric communication channel

    Czech Academy of Sciences Publication Activity Database

    Rejfek, Luboš; Mošna, Zbyšek; Beran, L.; Chmelař, P.; Chmelařová, N.; Dobrovolný, P.; Rozsíval, P.

    2015-01-01

    Roč. 2, č. 12 (2015), s. 67-71 ISSN 2313-626X R&D Projects: GA ČR(CZ) GAP209/12/2440 Institutional support: RVO:68378289 Keywords : Ionospheric communication channel * Digisonde * Continuous Doppler Sounding System Subject RIV: DG - Athmosphere Science s, Meteorology http://www. science -gate.com/IJAAS/ Articles /2015-2-12/12%202015-2-12-pp.67-71.pdf

  8. Channel Model of Molecular Communication via Diffusion in a Vessel-like Environment Considering a Partially Covering Receiver

    OpenAIRE

    Turan, Meriç; Kuran, Mehmet Sukru; Yilmaz, H. Birkan; Demirkol, Ilker; Tugcu, Tuna

    2018-01-01

    By considering potential health problems that a fully covering receiver may cause in vessel-like environments, the implementation of a partially covering receiver is needed. To this end, distribution of hitting location of messenger molecules (MM) is analyzed within the context of molecular communication via diffusion with the aim of channel modeling. The distribution of these MMs for a fully covering receiver is analyzed in two parts: angular and radial dimensions. For the angular distributi...

  9. On limits of Wireless Communications in a Fading Environment: a General Parameterization Quantifying Performance in Fading Channel

    Directory of Open Access Journals (Sweden)

    Amit Grover

    2014-08-01

    Full Text Available The reliable services along with high throughput can be achieved by using wireless communication systems. These systems also provides a wide coverage because of their features, no doubt MIMO Communication System [1] is one among them. Features provided by these systems ensure the improved system coverage and increased data transmission rate by considering multiple numbers of transmitter and receiver antennas. In this article, the concept of equalization has been considered and finally the performance of the MIMO Systems in Rician flat fading [5] channel is compared with the Rayleigh flat fading channel. It has also been observed that the performance of these Systems in Rician Flat Fading Channel is the best as compare to the Rayleigh Flat Fading Channel [10]. It has been concluded that the successive interference methods provide better performance as compare to others, but their complexity is high. Simulation results shows that ML provides the better performance in comparison to other equalizers but Sphere decoder provides the best performance.

  10. Human-Computer Interaction The Agency Perspective

    CERN Document Server

    Oliveira, José

    2012-01-01

    Agent-centric theories, approaches and technologies are contributing to enrich interactions between users and computers. This book aims at highlighting the influence of the agency perspective in Human-Computer Interaction through a careful selection of research contributions. Split into five sections; Users as Agents, Agents and Accessibility, Agents and Interactions, Agent-centric Paradigms and Approaches, and Collective Agents, the book covers a wealth of novel, original and fully updated material, offering:   ü  To provide a coherent, in depth, and timely material on the agency perspective in HCI ü  To offer an authoritative treatment of the subject matter presented by carefully selected authors ü  To offer a balanced and broad coverage of the subject area, including, human, organizational, social, as well as technological concerns. ü  To offer a hands-on-experience by covering representative case studies and offering essential design guidelines   The book will appeal to a broad audience of resea...

  11. Channel correlation of free space optical communication systems with receiver diversity in non-Kolmogorov atmospheric turbulence

    Science.gov (United States)

    Ma, Jing; Fu, Yulong; Tan, Liying; Yu, Siyuan; Xie, Xiaolong

    2018-05-01

    Spatial diversity as an effective technique to mitigate the turbulence fading has been widely utilized in free space optical (FSO) communication systems. The received signals, however, will suffer from channel correlation due to insufficient spacing between component antennas. In this paper, the new expressions of the channel correlation coefficient and specifically its components (the large- and small-scale channel correlation coefficients) for a plane wave with aperture effects are derived for horizontal link in moderate-to-strong turbulence, using a non-Kolmogorov spectrum that has a generalized power law in the range of 3-4 instead of the fixed classical Kolmogorov power law of 11/3. And then the influence of power law variations on the channel correlation coefficient and its components are analysed. The numerical results indicated that various value of the power law lead to varying effects on the channel correlation coefficient and its components. This work will help with the further investigation on the fading correlation in spatial diversity systems.

  12. Performance Analysis of a Six-Port Receiver in a WCDMA Communication System including a Multipath Fading Channel

    Directory of Open Access Journals (Sweden)

    A. O. Olopade

    2014-01-01

    Full Text Available Third generation communication systems require receivers with wide bandwidth of operation to support high transmission rates and are also reconfigurable to support various communication standards with different frequency bands. An ideal software defined radio (SDR will be the absolute answer to this requirement but it is not achievable with the current level of technology. This paper proposes the use of a six-port receiver (SPR front-end (FE in a WCDMA communication system. A WCDMA end-to-end physical layer MATLAB demo which includes a multipath channel distortion block is used to determine the viability of the six-port based receiver. The WCDMA signal after passing through a multipath channel is received using a constructed SPR FE. The baseband signal is then calibrated and corrected in MATLAB. The six-port receiver performance is measured in terms of bit error rate (BER. The signal-to-noise ratio (SNR of the transmitted IQ data is varied and the BER profile of the communication system is plotted. The effect of the multipath fading on the receiver performance and the accuracy of the calibration algorithm are obtained by comparing two different measured BER curves for different calibration techniques to the simulated BER curve of an ideal receiver.

  13. Channel Estimation on the (EW RLS Algorithm Model of MIMO OFDM in Wireless Communication

    Directory of Open Access Journals (Sweden)

    Sarnin Suzi Seroja

    2016-01-01

    (correspond to different mobility speeds and Monte Carlo simulations are performed and the MSE and BER performance versus SNR are obtained by averaging over 10000 channel realization. For comparisons, the BER performance is also presented for perfectly known channel at the receiver. In all the simulations, perfect synchronization between the transmitter and the receiver is assumed.

  14. Enhanced UWB Radio Channel Model for Short-Range Communication Scenarios Including User Dynamics

    DEFF Research Database (Denmark)

    Kovacs, Istvan Zsolt; Nguyen, Tuan Hung; Eggers, Patrick Claus F.

    2005-01-01

    channel model represents an enhancement of the existing IEEE 802.15.3a/4a PAN channel model, where antenna and user-proximity effects are not included. Our investigations showed that significant variations of the received wideband power and time-delay signal clustering are possible due the human body...

  15. Anticipated Ongoing Interaction versus Channel Effects of Relational Communication in Computer-Mediated Interaction.

    Science.gov (United States)

    Walther, Joseph B.

    1994-01-01

    Assesses the related effects of anticipated future interaction and different communication media (computer-mediated versus face-to-face communication) on the communication of relational intimacy and composure. Shows that the assignment of long-term versus short-term partnerships has a larger impact on anticipated future interaction reported by…

  16. Distinct moieties underlie biphasic H+ gating of connexin43 channels, producing a pH optimum for intercellular communication

    Science.gov (United States)

    Garciarena, Carolina D.; Malik, Akif; Swietach, Pawel; Moreno, Alonso P.; Vaughan-Jones, Richard D.

    2018-01-01

    Most mammalian cells can intercommunicate via connexin-assembled, gap-junctional channels. To regulate signal transmission, connexin (Cx) channel permeability must respond dynamically to physiological and pathophysiological stimuli. One key stimulus is intracellular pH (pHi), which is modulated by a tissue’s metabolic and perfusion status. Our understanding of the molecular mechanism of H+ gating of Cx43 channels—the major isoform in the heart and brain—is incomplete. To interrogate the effects of acidic and alkaline pHi on Cx43 channels, we combined voltage-clamp electrophysiology with pHi imaging and photolytic H+ uncaging, performed over a range of pHi values. We demonstrate that Cx43 channels expressed in HeLa or N2a cell pairs are gated biphasically by pHi via a process that consists of activation by H+ ions at alkaline pHi and inhibition at more acidic pHi. For Cx43 channel–mediated solute/ion transmission, the ensemble of these effects produces a pHi optimum, near resting pHi. By using Cx43 mutants, we demonstrate that alkaline gating involves cysteine residues of the C terminus and is independent of motifs previously implicated in acidic gating. Thus, we present a molecular mechanism by which cytoplasmic acid–base chemistry fine tunes intercellular communication and establishes conditions for the optimal transmission of solutes and signals in tissues, such as the heart and brain.—Garciarena, C. D., Malik, A., Swietach, P., Moreno, A. P., Vaughan-Jones, R. D. Distinct moieties underlie biphasic H+ gating of connexin43 channels, producing a pH optimum for intercellular communication. PMID:29183963

  17. Characterizing New Channels of Communication: A Case Study of Municipal 311 Requests in Edmonton, Canada

    Directory of Open Access Journals (Sweden)

    Qing Lu

    2016-06-01

    Full Text Available City governments around the world are developing and expanding how they connect to citizens. Technologies play an important role in making this connection, and one frequent way that cities connect with citizens is through 311-style request systems. 311 is a non-emergency municipal notification system that uses telephone, email, web forms, and increasingly, mobile applications to allow citizens to notify government of infrastructure issues and make requests for municipal services. In many ways, this process of citizen contribution mirrors the provision of volunteered geographic information, that is spatially-referenced user generated content. This research presents a case study of the city of Edmonton, Canada, an early adopter of multi-channel 311 service request systems, including telephone, email, web form, and mobile app 311 request channels. Three methods of analysis are used to characterize and compare these different channels over three years of request data; a comparison of relative request share for each channel, a spatial hot spot analysis, and regression models to compare channel usage with sociodemographic variables. The results of this study indicate a shift in channel usage from traditional to Internet-enabled, that this shift is mirrored in the hotspots of request activity, and that specific digital inequalities exist that reinforce this distinction between traditional and Internet-enabled reporting channels.

  18. The Use of Celebrity Endorsement with the Help of Electronic Communication Channel (Instagram) : Case study of Magnum Ice Cream in Thailand

    OpenAIRE

    Kutthakaphan, Rangsima; Chokesamritpol, Wahloonluck

    2013-01-01

    TITLE The Use of Celebrity Endorsement with the Help of Electronic Communication Channel (Instagram): Case Study of Magnum Ice Cream Thailand RESEARCH QUESTION How does the use of celebrity endorsement with the help of electronic communication channel (Social media: Instagram) affect the buying behavior of generation Y consumers in Thailand? STRATEGIC QUESTION How can marketers use this marketing technique in an effective way to increase the number of consumers? PURPOSE OF THE STUDY The pu...

  19. Security of quantum key distribution with a laser reference coherent state, resistant to loss in the communication channel

    International Nuclear Information System (INIS)

    Molotkov, S N; Potapova, T A

    2015-01-01

    The problem of quantum key distribution security in channels with large losses is still open. Quasi-single-photon sources of quantum states with losses in the quantum communication channel open up the possibility of attacking with unambiguous state discrimination (USD) measurements, resulting in a loss of privacy. In this letter, the problem is solved by counting the classic reference pulses. Conservation of the number of counts of intense coherent pulses makes it impossible to conduct USD measurements. Moreover, the losses in the communication channel are considered to be unknown in advance and are subject to change throughout the series parcels. Unlike other protocols, differential phase shift (Inoue et al 2002 Phys. Rev. Lett. 89 037902, Inoue et al 2003 Phys. Rev. A 68 022317, Takesue et al 2007 Nat. Photon. 1 343, Wen et al 2009 Phys. Rev. Lett. 103 170503) and coherent one way (Stucki et al 2005 Appl. Phys. Lett. 87 194108, Branciard et al 2005 Appl. Phys. Lett. 87 194108, Branciard et al 2008 New J. Phys. 10 013031, Stucki et al 2008 Opt. Express 17 13326), the simplicity of the protocol makes it possible to carry out a complete analysis of its security. (letter)

  20. Performance Limits of Online Energy Harvesting Communications with Noisy Channel State Information at the Transmitter

    KAUST Repository

    Zenaidi, Mohamed Ridha; Rezki, Zouheir; Alouini, Mohamed-Slim

    2017-01-01

    to mobility and environmental changes. In this paper, we consider the problem of power allocation taking into account the energy arrivals over time and the quality of channel state information (CSI) measured at the transmitter, in order to maximize

  1. Predicting automatic speech recognition performance over communication channels from instrumental speech quality and intelligibility scores

    NARCIS (Netherlands)

    Gallardo, L.F.; Möller, S.; Beerends, J.

    2017-01-01

    The performance of automatic speech recognition based on coded-decoded speech heavily depends on the quality of the transmitted signals, determined by channel impairments. This paper examines relationships between speech recognition performance and measurements of speech quality and intelligibility

  2. Cooperative jamming power control to enhance secrecy communications of AF Relaying systems for Rayleigh fading channel

    KAUST Repository

    Park, Kihong; Alouini, Mohamed-Slim

    2012-01-01

    allocation; (i) rate-optimal power allocation and (ii) outage-optimal power allocation. More specifically, without the instantaneous channel knowledge for the eavesdropper side, the outage probability of the secrecy rate is minimized with respect

  3. Performance Limits of Energy Harvesting Communications under Imperfect Channel State Information

    KAUST Repository

    Zenaidi, Mohamed Ridah; Rezki, Zouheir; Tembine, Hamidou; Alouini, Mohamed-Slim

    2015-01-01

    to mobility and environmental changes. In this work, we consider the problem of power allocation taking into account the energy arrivals over time and the degree of channel state information (CSI) available at the transmitter, in order to maximize

  4. Performance limits of energy harvesting communications under imperfect channel state information

    KAUST Repository

    Zenaidi, Mohamed Ridha; Rezki, Zouheir; Tembine, Hamidou; Alouini, Mohamed-Slim

    2016-01-01

    to mobility and environmental changes. In this paper, we consider the problem of power allocation taking into account the energy arrivals over time and the degree of channel state information (CSI) available at the transmitter, in order to maximize

  5. On Communications under Stochastic Energy Harvesting with Noisy Channel State Information

    KAUST Repository

    Zenaidi, Mohamed Ridha; Rezki, Zouheir; Alouini, Mohamed-Slim

    2017-01-01

    environmental changes. In this paper, we consider the problem of power allocation taking into account the energy arrivals over time and imperfect channel state information (CSI) available at the transmitter, in order to maximize the throughput. Differently from

  6. Effect of communication channels on success rate of entrepreneurial SMEs in the agricultural sector (a case study

    Directory of Open Access Journals (Sweden)

    Z. Khoshnodifar

    2016-01-01

    Full Text Available The present research aimed at investigating the effect of communication channels on the economic success of early profitable and entrepreneur small and medium enterprises in the agricultural sector. It was an applied research in which the descriptive-survey method was used. The research sample included 356 founders of entrepreneur small and medium enterprises (at the time of conducting the research in the Markazi province, Iran, among which 100 founders were selected according to the Cochran formulation using the stratified random sampling method. A questionnaire was used as the research tool and its validity was confirmed as the face validity by a group of teachers and experts. The questionnaire’s reliability was calculated using Cronbach’s alpha (α = 0.82. The results indicated that the information seeking facilities of most of the entrepreneurs were seen at a good level (53 persons, 53% and acquiring information from other businesses and consulting contacts with the neighbors and relatives, product sellers and promoting factors were listed as the highest priorities of the respondents, respectively. Also, there was a meaningful relationship between rate of using information and communication resources with the variables namely age, duration of operation on the job, number of people operating the business and number using loans. The results of regression analysis indicated that seven communication channels, promoters, other producers, product sellers, group visit, training films, creditors, radio and TV in the order of significance have defined 78.4% of the dependent variable changes.

  7. Orbital angular momentum in four channel spatial domain multiplexing system for multi-terabit per second communication architectures

    Science.gov (United States)

    Murshid, Syed H.; Muralikrishnan, Hari P.; Kozaitis, Samuel P.

    2012-06-01

    Bandwidth increase has always been an important area of research in communications. A novel multiplexing technique known as Spatial Domain Multiplexing (SDM) has been developed at the Optronics Laboratory of Florida Institute of Technology to increase the bandwidth to T-bits/s range. In this technique, space inside the fiber is used effectively to transmit up to four channels of same wavelength at the same time. Experimental and theoretical analysis shows that these channels follow independent helical paths inside the fiber without interfering with each other. Multiple pigtail laser sources of exactly the same wavelength are used to launch light into a single carrier fiber in a fashion that resulting channels follow independent helical trajectories. These helically propagating light beams form optical vortices inside the fiber and carry their own Orbital Angular Momentum (OAM). The outputs of these beams appear as concentric donut shaped rings when projected on a screen. This endeavor presents the experimental outputs and simulated results for a four channel spatially multiplexed system effectively increasing the system bandwidth by a factor of four.

  8. The Security Analysis of Two-Step Quantum Direct Communication Protocol in Collective-Rotation Noise Channel

    International Nuclear Information System (INIS)

    Li Jian; Sun Feng-Qi; Pan Ze-Shi; Nie Jin-Rui; Chen Yan-Hua; Yuan Kai-Guo

    2015-01-01

    To analyze the security of two-step quantum direct communication protocol (QDCP) by using Einstein–Podolsky–Rosen pair proposed by Deng et al. [Phys. Rev. A 68 (2003) 042317] in collective-rotation noise channel, an excellent model of noise analysis is proposed. In the security analysis, the method of the entropy theory is introduced, and is compared with QDCP, an error rate point Q 0 (M : (Q 0 , 1.0)) is given. In different noise levels, if Eve wants to obtain the same amount of information, the error rate Q is distinguishable. The larger the noise level ϵ is, the larger the error rate Q is. When the noise level ϵ is lower than 11%, the high error rate is 0.153 without eavesdropping. Lastly, the security of the proposed protocol is discussed. It turns out that the quantum channel will be safe when Q < 0.153. Similarly, if error rate Q > 0.153 = Q 0 , eavesdropping information I > 1, which means that there exist eavesdroppers in the quantum channel, and the quantum channel will not be safe anymore. (paper)

  9. Marketing hygiene behaviours: the impact of different communication channels on reported handwashing behaviour of women in Ghana.

    Science.gov (United States)

    Scott, Beth E; Schmidt, Wolf P; Aunger, Robert; Garbrah-Aidoo, Nana; Animashaun, Rasaaque

    2008-06-01

    In 2003-04, a National Handwashing Campaign utilizing mass media and community events took place in Ghana. This article describes the results of the evaluation of the campaign in a sample of 497 women with children channels was that hands were not 'truly' clean unless washed with soap. The campaign reached 82% of the study population. Sixty-two per cent of women knew the campaign song, 44% were exposed to one channel and 36% to two or more. Overall, TV and radio had greater reach and impact on reported handwashing than community events, while exposure to both a mass media channel and an event yielded the greatest effect, resulting in a 30% increase in reported handwashing with soap after visiting the toilet or cleaning a child's bottom. Our evaluation questions wide-held belief that community events are more effective agents of behaviour change than mass media commercials, at least in the case of hygiene promotion. However, failure of mass media to reach the entire target audience, particularly in specific regions and lower socio-economic groups, and the additive effect of exposure, underscores the need to implement integrated communication programmes utilizing a variety of complementary channels.

  10. Design and implementation of channel estimation for low-voltage power line communication systems based on OFDM

    International Nuclear Information System (INIS)

    Zhao Huidong; Hei Yong; Qiao Shushan; Ye Tianchun

    2012-01-01

    An optimized channel estimation algorithm based on a time-spread structure in OFDM low-voltage power line communication (PLC) systems is proposed to achieve a lower bit error rate (BER). This paper optimizes the best maximum multi-path delay of the linear minimum mean square error (LMMSE) algorithm in time-domain spread OFDM systems. Simulation results indicate that the BER of the improved method is lower than that of conventional LMMSE algorithm, especially when the signal-to-noise ratio (SNR) is lower than 0 dB. Both the LMMSE algorithm and the proposed algorithm are implemented and fabricated in CSMC 0.18 μm technology. This paper analyzes and compares the hardware complexity and performance of the two algorithms. Measurements indicate that the proposed channel estimator has better performance than the conventional estimator.

  11. Intercellular odontoblast communication via ATP mediated by pannexin-1 channel and phospholipase C-coupled receptor activation.

    Directory of Open Access Journals (Sweden)

    Masaki eSato

    2015-11-01

    Full Text Available Extracellular ATP released via pannexin-1 channels, in response to the activation of mechanosensitive-TRP channels during odontoblast mechanical stimulation, mediates intercellular communication among odontoblasts in dental pulp slice preparation dissected form rat incisor. Recently, odontoblast cell lines, such as mouse odontoblast lineage cells, have been widely used to investigate physiological/pathological cellular functions. To clarify whether the odontoblast cell lines also communicate with each other by diffusible chemical substance(s, we investigated the chemical intercellular communication among cells from mouse odontoblast cell lines following mechanical stimulation. A single cell was stimulated using a glass pipette filled with standard extracellular solution. We measured intracellular free Ca2+ concentration ([Ca2+]i by fura-2 in stimulated cells, as well as in cells located nearby. Direct mechanical stimulation to a single odontoblast increased [Ca2+]i, which showed sensitivity to capsazepine. In addition, we observed increases in [Ca2+]i not only in the mechanically stimulated odontoblast, but also in nearby odontoblasts. We could observe mechanical stimulation-induced increase in [Ca2+]i in a stimulated human embryo kidney (HEK 293 cell, but not in nearby HEK293 cells. The increase in [Ca2+]i in nearby odontoblasts, but not in the stimulated odontoblast, was inhibited by adenosine triphosphate (ATP release channel (pannexin-1 inhibitor in a concentration- and spatial-dependent manner. Moreover, in the presence of phospholipase C (PLC inhibitor, the increase in [Ca2+]i in nearby odontoblasts, following mechanical stimulation of a single odontoblast, was abolished. We could record some inward currents evoked from odontoblasts near the stimulated odontoblast, but the currents were observed in only 4.8% of the recorded odontoblasts. The results of this study showed that ATP is released via pannexin-1, from a mechanically stimulated

  12. Evidence Report: Risk of Inadequate Human-Computer Interaction

    Science.gov (United States)

    Holden, Kritina; Ezer, Neta; Vos, Gordon

    2013-01-01

    Human-computer interaction (HCI) encompasses all the methods by which humans and computer-based systems communicate, share information, and accomplish tasks. When HCI is poorly designed, crews have difficulty entering, navigating, accessing, and understanding information. HCI has rarely been studied in an operational spaceflight context, and detailed performance data that would support evaluation of HCI have not been collected; thus, we draw much of our evidence from post-spaceflight crew comments, and from other safety-critical domains like ground-based power plants, and aviation. Additionally, there is a concern that any potential or real issues to date may have been masked by the fact that crews have near constant access to ground controllers, who monitor for errors, correct mistakes, and provide additional information needed to complete tasks. We do not know what types of HCI issues might arise without this "safety net". Exploration missions will test this concern, as crews may be operating autonomously due to communication delays and blackouts. Crew survival will be heavily dependent on available electronic information for just-in-time training, procedure execution, and vehicle or system maintenance; hence, the criticality of the Risk of Inadequate HCI. Future work must focus on identifying the most important contributing risk factors, evaluating their contribution to the overall risk, and developing appropriate mitigations. The Risk of Inadequate HCI includes eight core contributing factors based on the Human Factors Analysis and Classification System (HFACS): (1) Requirements, policies, and design processes, (2) Information resources and support, (3) Allocation of attention, (4) Cognitive overload, (5) Environmentally induced perceptual changes, (6) Misperception and misinterpretation of displayed information, (7) Spatial disorientation, and (8) Displays and controls.

  13. Secured Communication over Frequency-Selective Fading Channels: A Practical Vandermonde Precoding

    Directory of Open Access Journals (Sweden)

    Mari Kobayashi

    2009-01-01

    Full Text Available We study the frequency-selective broadcast channel with confidential messages (BCC where the transmitter sends a confidential message to receiver 1 and a common message to receivers 1 and 2. In the case of a block transmission of N symbols followed by a guard interval of L symbols, the frequency-selective channel can be modeled as a N×(N+L Toeplitz matrix. For this special type of multiple-input multiple-output channels, we propose a practical Vandermonde precoding that projects the confidential messages in the null space of the channel seen by receiver 2 while superposing the common message. For this scheme, we provide the achievable rate region and characterize the optimal covariance for some special cases of interest. Interestingly, the proposed scheme can be applied to other multiuser scenarios such as the K+1-user frequency-selective BCC with K confidential messages and the two-user frequency-selective BCC with two confidential messages. For each scenario, we provide the secrecy degree of freedom (s.d.o.f. region of the corresponding channel and prove the optimality of the Vandermonde precoding. One of the appealing features of the proposed scheme is that it does not require any specific secrecy encoding technique but can be applied on top of any existing powerful encoding schemes.

  14. Secured Communication over Frequency-Selective Fading Channels: A Practical Vandermonde Precoding

    Directory of Open Access Journals (Sweden)

    Debbah Mérouane

    2009-01-01

    Full Text Available We study the frequency-selective broadcast channel with confidential messages (BCC where the transmitter sends a confidential message to receiver 1 and a common message to receivers 1 and 2. In the case of a block transmission of symbols followed by a guard interval of symbols, the frequency-selective channel can be modeled as a Toeplitz matrix. For this special type of multiple-input multiple-output channels, we propose a practical Vandermonde precoding that projects the confidential messages in the null space of the channel seen by receiver 2 while superposing the common message. For this scheme, we provide the achievable rate region and characterize the optimal covariance for some special cases of interest. Interestingly, the proposed scheme can be applied to other multiuser scenarios such as the -user frequency-selective BCC with confidential messages and the two-user frequency-selective BCC with two confidential messages. For each scenario, we provide the secrecy degree of freedom (s.d.o.f. region of the corresponding channel and prove the optimality of the Vandermonde precoding. One of the appealing features of the proposed scheme is that it does not require any specific secrecy encoding technique but can be applied on top of any existing powerful encoding schemes.

  15. A novel unified expression for the capacity and bit error probability of wireless communication systems over generalized fading channels

    KAUST Repository

    Yilmaz, Ferkan

    2012-07-01

    Analysis of the average binary error probabilities (ABEP) and average capacity (AC) of wireless communications systems over generalized fading channels have been considered separately in past years. This paper introduces a novel moment generating function (MGF)-based unified expression for the ABEP and AC of single and multiple link communications with maximal ratio combining. In addition, this paper proposes the hyper-Fox\\'s H fading model as a unified fading distribution of a majority of the well-known generalized fading environments. As such, the authors offer a generic unified performance expression that can be easily calculated, and that is applicable to a wide variety of fading scenarios. The mathematical formulism is illustrated with some selected numerical examples that validate the correctness of the authors\\' newly derived results. © 1972-2012 IEEE.

  16. Human Computation An Integrated Approach to Learning from the Crowd

    CERN Document Server

    Law, Edith

    2011-01-01

    Human computation is a new and evolving research area that centers around harnessing human intelligence to solve computational problems that are beyond the scope of existing Artificial Intelligence (AI) algorithms. With the growth of the Web, human computation systems can now leverage the abilities of an unprecedented number of people via the Web to perform complex computation. There are various genres of human computation applications that exist today. Games with a purpose (e.g., the ESP Game) specifically target online gamers who generate useful data (e.g., image tags) while playing an enjoy

  17. Advances in Human-Computer Interaction: Graphics and Animation Components for Interface Design

    Science.gov (United States)

    Cipolla Ficarra, Francisco V.; Nicol, Emma; Cipolla-Ficarra, Miguel; Richardson, Lucy

    We present an analysis of communicability methodology in graphics and animation components for interface design, called CAN (Communicability, Acceptability and Novelty). This methodology has been under development between 2005 and 2010, obtaining excellent results in cultural heritage, education and microcomputing contexts. In studies where there is a bi-directional interrelation between ergonomics, usability, user-centered design, software quality and the human-computer interaction. We also present the heuristic results about iconography and layout design in blogs and websites of the following countries: Spain, Italy, Portugal and France.

  18. Channel modelling and performance analysis of V2I communication systems in blind bend scattering environments

    KAUST Repository

    Chelli, Ali; Hamdi, Rami; Alouini, Mohamed-Slim

    2014-01-01

    In this paper, we derive a new geometrical blind bend scattering model for vehicle-to- infrastructure (V2I) communications. The proposed model takes into account single-bounce and double- bounce scattering stemming from fixed scatterers located

  19. Underwater Wireless Optical Communications Systems: from System-Level Demonstrations to Channel Modeling

    KAUST Repository

    Oubei, Hassan M.

    2018-01-01

    Approximately, two-thirds of earth's surface is covered by water. There is a growing interest from the military and commercial communities in having, an efficient, secure and high bandwidth underwater wireless communication (UWC) system for tactical

  20. Near-Infrared Wireless Optical Communication with Particulates In-Suspension over the Underwater Channel

    KAUST Repository

    Lee, It Ee; Guo, Yong; Ng, Tien Khee; Park, Kihong; Alouini, Mohamed-Slim; Ooi, Boon S.

    2017-01-01

    We demonstrate a gigabit near-infrared-based underwater wireless optical communication link using an 808-nm laser diode to mitigate the particle scattering effect in turbid medium. An improvement in the error performance is observed with increasing

  1. Ultra-fast secure communication with complex systems in classical channels (Conference Presentation)

    KAUST Repository

    Mazzone, Valerio; Di Falco, Andrea; Fratalocchi, Andrea

    2017-01-01

    Developing secure communications is a research area of growing interest. During the past years, several cryptographic schemes have been developed, with Quantum cryptography being a promising scheme due to the use of quantum effects, which make very

  2. Near-Infrared Wireless Optical Communication with Particulates In-Suspension over the Underwater Channel

    KAUST Repository

    Lee, It Ee

    2017-05-08

    We demonstrate a gigabit near-infrared-based underwater wireless optical communication link using an 808-nm laser diode to mitigate the particle scattering effect in turbid medium. An improvement in the error performance is observed with increasing concentrations.

  3. Range extension and channel capacity increase in impulse-radio ultra-wideband communications

    DEFF Research Database (Denmark)

    Rodes Lopez, Roberto; Yu, Xianbin; Caballero Jambrina, Antonio

    2010-01-01

    We theoretically analyze the channel capacity of a 5th-order Gaussian pulse-based ultra-wideband (UWB) system and experimentally demonstrate 2 Gbit/s UWB-over-fiber transmission systems incorporating wireless transmission. Both electrical and photonic UWB pulse generation methods are employed...

  4. Entanglement-enhanced communication over a quantum channel with correlated noise

    International Nuclear Information System (INIS)

    Banaszek, K.; Dragan, A.; Wasilewski, W.; Radzewicz, C.

    2005-01-01

    We present an experimental demonstration of entanglement enhanced classical capacity of a quantum channel with correlated noise. The channel is modelled by a fiber optic link exhibiting random birefringence that fluctuates on a time scale much longer than the temporal separation between consecutive uses of the channel. In this setting, it can be shown theoretically that introducing entanglement between two photons travelling down the fiber allows one to encode reliably one bit of information into their polarization degree of freedom. When no quantum correlations between two separate uses of the channel are allowed, this capacity is reduced by a factor of more than three. To demonstrate experimentally this effect, we generated polarization-entangled pairs of photons in either a singlet or a triplet state, corresponding to the two values of a classical bit. The pairs were then launched into a single-mode fiber submitted to random mechanical movements, scrambling the polarization state of the travelling light. At the output of the fiber, the photon pairs were detected using the Braunstein-Mann Bell state analyzer that allowed us to discriminate unambiguously the input singlet state against the triplet one despite polarization scrambling. To contrast this with the separable case, we also generated disentangled photon pairs and encoded information into their relative polarization. As predicted theoretically, after scrambling only partial information about the input state was retrieved. (author)

  5. An Underlay Communication Channel for 5G Cognitive Mesh Networks: Packet Design, Implementation, Analysis, and Experimental Results

    Energy Technology Data Exchange (ETDEWEB)

    Tarek Haddadin; Stephen Andrew Laraway; Arslan Majid; Taylor Sibbett; Daryl Leon Wasden; Brandon F Lo; Lloyd Landon; David Couch; Hussein Moradi; Behrouz Farhang-Boroujeny

    2016-04-01

    This paper proposes and presents the design and implementation of an underlay communication channel (UCC) for 5G cognitive mesh networks. The UCC builds its waveform based on filter bank multicarrier spread spectrum (FB-MCSS) signaling. The use of this novel spread spectrum signaling allows the device-to-device (D2D) user equipments (UEs) to communicate at a level well below noise temperature and hence, minimize taxation on macro-cell/small-cell base stations and their UEs in 5G wireless systems. Moreover, the use of filter banks allows us to avoid those portions of the spectrum that are in use by macro-cell and small-cell users. Hence, both D2D-to-cellular and cellular-to-D2D interference will be very close to none. We propose a specific packet for UCC and develop algorithms for packet detection, timing acquisition and tracking, as well as channel estimation and equalization. We also present the detail of an implementation of the proposed transceiver on a software radio platform and compare our experimental results with those from a theoretical analysis of our packet detection algorithm.

  6. Mobile human-computer interaction perspective on mobile learning

    CSIR Research Space (South Africa)

    Botha, Adèle

    2010-10-01

    Full Text Available Applying a Mobile Human Computer Interaction (MHCI) view to the domain of education using Mobile Learning (Mlearning), the research outlines its understanding of the influences and effects of different interactions on the use of mobile technology...

  7. Human-Computer Interaction and Information Management Research Needs

    Data.gov (United States)

    Networking and Information Technology Research and Development, Executive Office of the President — In a visionary future, Human-Computer Interaction HCI and Information Management IM have the potential to enable humans to better manage their lives through the use...

  8. Piezo-Phototronic Effect Controlled Dual-Channel Visible light Communication (PVLC) Using InGaN/GaN Multiquantum Well Nanopillars.

    Science.gov (United States)

    Du, Chunhua; Jiang, Chunyan; Zuo, Peng; Huang, Xin; Pu, Xiong; Zhao, Zhenfu; Zhou, Yongli; Li, Linxuan; Chen, Hong; Hu, Weiguo; Wang, Zhong Lin

    2015-12-02

    Visible light communication (VLC) simultaneously provides illumination and communication via light emitting diodes (LEDs). Keeping a low bit error rate is essential to communication quality, and holding a stable brightness level is pivotal for illumination function. For the first time, a piezo-phototronic effect controlled visible light communication (PVLC) system based on InGaN/GaN multiquantum wells nanopillars is demonstrated, in which the information is coded by mechanical straining. This approach of force coding is also instrumental to avoid LED blinks, which has less impact on illumination and is much safer to eyes than electrical on/off VLC. The two-channel transmission mode of the system here shows great superiority in error self-validation and error self-elimination in comparison to VLC. This two-channel PVLC system provides a suitable way to carry out noncontact, reliable communication under complex circumstances. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  9. Experimental research and comparison of LDPC and RS channel coding in ultraviolet communication systems.

    Science.gov (United States)

    Wu, Menglong; Han, Dahai; Zhang, Xiang; Zhang, Feng; Zhang, Min; Yue, Guangxin

    2014-03-10

    We have implemented a modified Low-Density Parity-Check (LDPC) codec algorithm in ultraviolet (UV) communication system. Simulations are conducted with measured parameters to evaluate the LDPC-based UV system performance. Moreover, LDPC (960, 480) and RS (18, 10) are implemented and experimented via a non-line-of-sight (NLOS) UV test bed. The experimental results are in agreement with the simulation and suggest that based on the given power and 10(-3)bit error rate (BER), in comparison with an uncoded system, average communication distance increases 32% with RS code, while 78% with LDPC code.

  10. Controlled quantum secure direct communication using a non-symmetric quantum channel with quantum superdense coding

    International Nuclear Information System (INIS)

    Xia, Yan; Song, He-Shan

    2007-01-01

    We present a controlled quantum secure direct communication protocol that uses a 2-dimensional Greenberger-Horne-Zeilinger (GHZ) entangled state and a 3-dimensional Bell-basis state and employs the high-dimensional quantum superdense coding, local collective unitary operations and entanglement swapping. The proposed protocol is secure and of high source capacity. It can effectively protect the communication against a destroying-travel-qubit-type attack. With this protocol, the information transmission is greatly increased. This protocol can also be modified, so that it can be used in a multi-party control system

  11. 12.5 Gb/s multi-channel broadcasting transmission for free-space optical communication based on the optical frequency comb module.

    Science.gov (United States)

    Tan, Jun; Zhao, Zeping; Wang, Yuehui; Zhang, Zhike; Liu, Jianguo; Zhu, Ninghua

    2018-01-22

    A wide-spectrum, ultra-stable optical frequency comb (OFC) module with 100 GHz frequency intervals based on a quantum dot mode locked (QDML) laser is fabricated by our lab, and a scheme with 12.5 Gb/s multi-channel broadcasting transmission for free-space optical (FSO) communication is proposed based on the OFC module. The output power of the OFC is very stable, with the specially designed circuit and the flatness of the frequency comb over the span of 6 nm, which can be limited to 1.5 dB. Four channel wavelengths are chosen to demonstrate one-to-many channels for FSO communication, like optical wireless broadcast. The outdoor experiment is established to test the bit error rate (BER) and eye diagrams with 12.5 Gb/s on-off keying (OOK). The indoor experiment is used to test the highest traffic rate, which is up to 21 Gb/s for one-hop FSO communication. To the best of our knowledge, this scheme is the first to propose the realization of one-to-many broadcasting transmission for FSO communication based on the OFC module. The advantages of integration, miniaturization, channelization, low power consumption, and unlimited bandwidth of one-to-many broadcasting communication scheme, shows promising results on constructing the future space-air-ground-ocean (SAGO) FSO communication networks.

  12. Performance Analysis of Free-Space Optical Communication Systems With Multiuser Diversity Over Atmospheric Turbulence Channels

    KAUST Repository

    Yang, Liang; Gao, Xiqi; Alouini, Mohamed-Slim

    2014-01-01

    Free-space optical (FSO) communication has become a cost-effective method to provide high data rates. However, the turbulence-induced fading limits its application to short-range applications. To address this, we propose a multiuser diversity (MD

  13. Computer-mediated communication as a channel for social resistance : The strategic side of SIDE

    NARCIS (Netherlands)

    Spears, R; Lea, M; Corneliussen, RA; Postmes, T; Ter Haar, W

    2002-01-01

    In two studies, the authors tested predictions derived from the social identity model of deindividuation effects (SIDE) concerning the potential of computer-mediated communication (CMC) to serve as a means to resist powerful out-groups. Earlier research using the SIDE model indicates that the

  14. RF model of the distribution system as a communication channel, phase 2. Volume 2: Task reports

    Science.gov (United States)

    Rustay, R. C.; Gajjar, J. T.; Rankin, R. W.; Wentz, R. C.; Wooding, R.

    1982-01-01

    Based on the established feasibility of predicting, via a model, the propagation of Power Line Frequency on radial type distribution feeders, verification studies comparing model predictions against measurements were undertaken using more complicated feeder circuits and situations. Detailed accounts of the major tasks are presented. These include: (1) verification of model; (2) extension, implementation, and verification of perturbation theory; (3) parameter sensitivity; (4) transformer modeling; and (5) compensation of power distribution systems for enhancement of power line carrier communication reliability.

  15. BER Performance of Stratified ACO-OFDM for Optical Wireless Communications over Multipath Channel

    OpenAIRE

    Gebeyehu, Zelalem Hailu; Langat, Philip Kibet; Maina, Ciira Wa

    2018-01-01

    In intensity modulation/direct detection- (IM/DD-) based optical OFDM systems, the requirement of the input signal to be real and positive unipolar imposes a reduction of system performances. Among previously proposed unipolar optical OFDM schemes for optical wireless communications (OWC), asymmetrically clipped optical OFDM (ACO-OFDM) and direct current biased optical OFDM (DCO-OFDM) are the most accepted ones. But those proposed schemes experience either spectral efficiency loss or energy e...

  16. Parity-Check Network Coding for Multiple Access Relay Channel in Wireless Sensor Cooperative Communications

    Directory of Open Access Journals (Sweden)

    Du Bing

    2010-01-01

    Full Text Available A recently developed theory suggests that network coding is a generalization of source coding and channel coding and thus yields a significant performance improvement in terms of throughput and spatial diversity. This paper proposes a cooperative design of a parity-check network coding scheme in the context of a two-source multiple access relay channel (MARC model, a common compact model in hierarchical wireless sensor networks (WSNs. The scheme uses Low-Density Parity-Check (LDPC as the surrogate to build up a layered structure which encapsulates the multiple constituent LDPC codes in the source and relay nodes. Specifically, the relay node decodes the messages from two sources, which are used to generate extra parity-check bits by a random network coding procedure to fill up the rate gap between Source-Relay and Source-Destination transmissions. Then, we derived the key algebraic relationships among multidimensional LDPC constituent codes as one of the constraints for code profile optimization. These extra check bits are sent to the destination to realize a cooperative diversity as well as to approach MARC decode-and-forward (DF capacity.

  17. Connexin 43 Communication Channels in Follicular Dendritic Cell Development and in Follicular Lymphomas

    Directory of Open Access Journals (Sweden)

    Hajnalka Rajnai

    2015-01-01

    Full Text Available Follicular dendritic cells (FDC show homo- and heterocellular metabolic coupling through connexin 43 (Cx43 gap junctions and support B cell selection and maturation in germinal centers. In follicular lymphomas B cells escape apoptosis while FDC develop abnormally. Here we tested Cx43 channels in reactive FDC development and follicular lymphomas. In culture, the treatment of FDC-B cell clusters (resembling to “ex vivo” germinal centers with Gap27 peptide, mimicking the 2nd extracellular loop of Cx43 protein, significantly impaired FDC-B cell cluster formation and cell survival. In untreated cultures of intact clusters, cell proliferation showed a moderate reduction. In tissues, Cx43 protein levels run parallel with the density of FDC both in reactive germinal centers and in malformed follicles of follicular lymphomas and showed strong upregulation in newly generated and/or degrading bi-/multinuclear FDC of rudimentary processes. However, the inverse correlation between Cx43 expression and B cell proliferation seen in reactive germinal centers was not detected in follicular lymphomas. Furthermore, Cx43 levels were not associated with either lymphoma grade or bone marrow involvement. Our results suggest that Cx43 channels are critical in FDC and “ex vivo” germinal center development and in the persistence of FDC in follicular lymphomas but do not affect tumor progression.

  18. Adaptive Space-Time-Spreading-Assisted Wideband CDMA Systems Communicating over Dispersive Nakagami- Fading Channels

    Directory of Open Access Journals (Sweden)

    Yang Lie-Liang

    2005-01-01

    Full Text Available In this contribution, the performance of wideband code-division multiple-access (W-CDMA systems using space-time-spreading- (STS- based transmit diversity is investigated, when frequency-selective Nakagami- fading channels, multiuser interference, and background noise are considered. The analysis and numerical results suggest that the achievable diversity order is the product of the frequency-selective diversity order and the transmit diversity order. Furthermore, both the transmit diversity and the frequency-selective diversity have the same order of importance. Since W-CDMA signals are subjected to frequency-selective fading, the number of resolvable paths at the receiver may vary over a wide range depending on the transmission environment encountered. It can be shown that, for wireless channels where the frequency selectivity is sufficiently high, transmit diversity may be not necessitated. Under this case, multiple transmission antennas can be leveraged into an increased bitrate. Therefore, an adaptive STS-based transmission scheme is then proposed for improving the throughput of W-CDMA systems. Our numerical results demonstrate that this adaptive STS-based transmission scheme is capable of significantly improving the effective throughput of W-CDMA systems. Specifically, the studied W-CDMA system's bitrate can be increased by a factor of three at the modest cost of requiring an extra 0.4 dB or 1.2 dB transmitted power in the context of the investigated urban or suburban areas, respectively.

  19. When a transmembrane channel isn't, or how biophysics and biochemistry (mis)communicate.

    Science.gov (United States)

    Reviakine, Ilya

    2018-02-12

    Annexins are a family of soluble proteins that bind to acidic phospholipids such as phosphatidylserine in a calcium-dependent manner. The archetypical member of the annexin family is annexin A5. For many years, its function remained unknown despite the availability of a high-resolution structure. This, combined with the observations of specific ion conductance in annexin-bound membranes, fueled speculations about the possible membrane-spanning forms of annexins that functioned as ion channels. The channel hypothesis remained controversial and did not gather sufficient evidence to become accepted. Yet, it continues to draw attention as a framework for interpreting indirect (e.g., biochemical) data. The goal of the mini-review is to examine the data on annexin-lipid interactions from the last ~30 years from the point of view of the controversy between the two lines of inquiry: the well-characterized peripheral assembly of the annexins at membranes vs. their putative transmembrane insertion. In particular, the potential role of lipid rearrangements induced by annexin binding is highlighted. Copyright © 2018 Elsevier B.V. All rights reserved.

  20. Experimental confirmation and physical understanding of ultra-high bit rate impulse radio in the THz digital communication channels of the atmosphere

    Science.gov (United States)

    Mandehgar, Mahboubeh; Yang, Yihong; Grischkowsky, D.

    2014-09-01

    We have performed highly accurate numerical calculations of high bit rate impulse propagation through the seven digital communication channels of the atmosphere at RH 58% (10 g m-3). These calculations maximized bit rates for pathlengths equal to or longer than 100 m. We have experimentally verified our calculations for three channels with a propagation pathlength of 137 m and RH 65% (11.2 g m-3). Excellent agreement between measurement and theory was obtained for Channel 3 at 252 GHz, bit rate 84 Gb s-1, FWHM bandwidth (BW) 180 GHz; Channel 6 at 672 GHz, 45 Gb s-1, BW 84 GHz; and Channel 7 at 852 GHz, 56.8 Gb s-1, BW 108 GHz.

  1. Experimental confirmation and physical understanding of ultra-high bit rate impulse radio in the THz digital communication channels of the atmosphere

    International Nuclear Information System (INIS)

    Mandehgar, Mahboubeh; Yang, Yihong; Grischkowsky, D

    2014-01-01

    We have performed highly accurate numerical calculations of high bit rate impulse propagation through the seven digital communication channels of the atmosphere at RH 58% (10 g m −3 ). These calculations maximized bit rates for pathlengths equal to or longer than 100 m. We have experimentally verified our calculations for three channels with a propagation pathlength of 137 m and RH 65% (11.2 g m −3 ). Excellent agreement between measurement and theory was obtained for Channel 3 at 252 GHz, bit rate 84 Gb s −1 , FWHM bandwidth (BW) 180 GHz; Channel 6 at 672 GHz, 45 Gb s −1 , BW 84 GHz; and Channel 7 at 852 GHz, 56.8 Gb s −1 , BW 108 GHz. (special issue article)

  2. Energy Efficient and Performance Analysis of Multihop Wireless Communication Over Nakagami-m Fading Channel

    KAUST Repository

    Randrianantenaina, Itsikiantsoa

    2015-01-01

    In this work, the performance of multihop communication over Nakagami-m fading is investigated for both cases without and with diversity combining. Closed form expressions of the average ergodic capacity are derived for each of these cases. Then, an expression of the outage probability is obtained using the inverse of Laplace transform and the average bit error rate is bounded using the Moment-Generating-Function approach. The energy efficiency is analyzed using the "consumption factor" as a metric, and it is derived in closed-form. And based on the obtained expressions, we propose a power allocation strategy maximizing this consumption factor.

  3. Improvement on Quantum Secure Direct Communication with W State in Noisy Channel

    International Nuclear Information System (INIS)

    Dong Li; Xiu Xiaoming; Gao Yajun; Chi Feng

    2009-01-01

    An improvement (Y-protocol) [Commun. Theor. Phys. 49 (2008) 103] on the quantum secure direct communication with W state (C-protocol) [Chin. Phys. Lett. 23 (2006) 290] is proposed by Yuan et al. The quantum bit error rate induced by eavesdropper is 4.17% in C-protocol and 6.25% in Y-protocol. In this paper, another improvement on C-protocol is given. The quantum bit error rate of the eavesdropping will increase to 8.75%, which is 1.1 times larger than that in C-protocol and 0.4 times larger than that in Y-protocol.

  4. Cross-cultural human-computer interaction and user experience design a semiotic perspective

    CERN Document Server

    Brejcha, Jan

    2015-01-01

    This book describes patterns of language and culture in human-computer interaction (HCI). Through numerous examples, it shows why these patterns matter and how to exploit them to design a better user experience (UX) with computer systems. It provides scientific information on the theoretical and practical areas of the interaction and communication design for research experts and industry practitioners and covers the latest research in semiotics and cultural studies, bringing a set of tools and methods to benefit the process of designing with the cultural background in mind.

  5. Accident sequence analysis of human-computer interface design

    International Nuclear Information System (INIS)

    Fan, C.-F.; Chen, W.-H.

    2000-01-01

    It is important to predict potential accident sequences of human-computer interaction in a safety-critical computing system so that vulnerable points can be disclosed and removed. We address this issue by proposing a Multi-Context human-computer interaction Model along with its analysis techniques, an Augmented Fault Tree Analysis, and a Concurrent Event Tree Analysis. The proposed augmented fault tree can identify the potential weak points in software design that may induce unintended software functions or erroneous human procedures. The concurrent event tree can enumerate possible accident sequences due to these weak points

  6. Human-computer interaction and management information systems

    CERN Document Server

    Galletta, Dennis F

    2014-01-01

    ""Human-Computer Interaction and Management Information Systems: Applications"" offers state-of-the-art research by a distinguished set of authors who span the MIS and HCI fields. The original chapters provide authoritative commentaries and in-depth descriptions of research programs that will guide 21st century scholars, graduate students, and industry professionals. Human-Computer Interaction (or Human Factors) in MIS is concerned with the ways humans interact with information, technologies, and tasks, especially in business, managerial, organizational, and cultural contexts. It is distinctiv

  7. The Next Wave: Humans, Computers, and Redefining Reality

    Science.gov (United States)

    Little, William

    2018-01-01

    The Augmented/Virtual Reality (AVR) Lab at KSC is dedicated to " exploration into the growing computer fields of Extended Reality and the Natural User Interface (it is) a proving ground for new technologies that can be integrated into future NASA projects and programs." The topics of Human Computer Interface, Human Computer Interaction, Augmented Reality, Virtual Reality, and Mixed Reality are defined; examples of work being done in these fields in the AVR Lab are given. Current new and future work in Computer Vision, Speech Recognition, and Artificial Intelligence are also outlined.

  8. A Novel Approach to Achieve the Perfect Security through AVK over Insecure Communication Channel

    Science.gov (United States)

    Banerjee, Subhasish; Dutta, Manash Pratim; Bhunia, Chandan Tilak

    2017-04-01

    To enhance the security level of the cryptosystem in shared encrypted data over the insecure channel; Automatic variable key (AVK) is a perfect mechanism as being experimented by many researchers. In AVK, after establishment of the secret key (through some IKE protocols, like IKEv2 or 2 PAKA or 3 PAKA, etc), the successive keys are generated that are variable in nature from session to session by using time variant key technique. In this work, it is shown that how AVK can provide higher security than fixed key from well-known plaintext attack (for example, brute force attack) and ciphertext only attack (for example, frequency attack etc) due to randomness of keys. In order to improve the level of randomness among the key set, a new method is proposed to generate keys where the randomness are achieved not only in terms of change in bits sequence but also flexible in size as well. Randomness of the key set is also compared with other related time variant key mechanisms to prove superiority.

  9. Brain-Computer Interfaces Revolutionizing Human-Computer Interaction

    CERN Document Server

    Graimann, Bernhard; Allison, Brendan

    2010-01-01

    A brain-computer interface (BCI) establishes a direct output channel between the human brain and external devices. BCIs infer user intent via direct measures of brain activity and thus enable communication and control without movement. This book, authored by experts in the field, provides an accessible introduction to the neurophysiological and signal-processing background required for BCI, presents state-of-the-art non-invasive and invasive approaches, gives an overview of current hardware and software solutions, and reviews the most interesting as well as new, emerging BCI applications. The book is intended not only for students and young researchers, but also for newcomers and other readers from diverse backgrounds keen to learn about this vital scientific endeavour.

  10. Measuring Multimodal Synchrony for Human-Computer Interaction

    NARCIS (Netherlands)

    Reidsma, Dennis; Nijholt, Antinus; Tschacher, Wolfgang; Ramseyer, Fabian; Sourin, A.

    2010-01-01

    Nonverbal synchrony is an important and natural element in human-human interaction. It can also play various roles in human-computer interaction. In particular this is the case in the interaction between humans and the virtual humans that inhabit our cyberworlds. Virtual humans need to adapt their

  11. Humor in Human-Computer Interaction : A Short Survey

    NARCIS (Netherlands)

    Nijholt, Anton; Niculescu, Andreea; Valitutti, Alessandro; Banchs, Rafael E.; Joshi, Anirudha; Balkrishan, Devanuj K.; Dalvi, Girish; Winckler, Marco

    2017-01-01

    This paper is a short survey on humor in human-computer interaction. It describes how humor is designed and interacted with in social media, virtual agents, social robots and smart environments. Benefits and future use of humor in interactions with artificial entities are discussed based on

  12. A Software Framework for Multimodal Human-Computer Interaction Systems

    NARCIS (Netherlands)

    Shen, Jie; Pantic, Maja

    2009-01-01

    This paper describes a software framework we designed and implemented for the development and research in the area of multimodal human-computer interface. The proposed framework is based on publish / subscribe architecture, which allows developers and researchers to conveniently configure, test and

  13. Humans, computers and wizards human (simulated) computer interaction

    CERN Document Server

    Fraser, Norman; McGlashan, Scott; Wooffitt, Robin

    2013-01-01

    Using data taken from a major European Union funded project on speech understanding, the SunDial project, this book considers current perspectives on human computer interaction and argues for the value of an approach taken from sociology which is based on conversation analysis.

  14. Human Computing and Machine Understanding of Human Behavior: A Survey

    NARCIS (Netherlands)

    Pantic, Maja; Pentland, Alex; Nijholt, Antinus; Huang, Thomas; Quek, F.; Yang, Yie

    2006-01-01

    A widely accepted prediction is that computing will move to the background, weaving itself into the fabric of our everyday living spaces and projecting the human user into the foreground. If this prediction is to come true, then next generation computing, which we will call human computing, should

  15. Multimodal Information Presentation for High-Load Human Computer Interaction

    NARCIS (Netherlands)

    Cao, Y.

    2011-01-01

    This dissertation addresses multimodal information presentation in human computer interaction. Information presentation refers to the manner in which computer systems/interfaces present information to human users. More specifically, the focus of our work is not on which information to present, but

  16. The epistemology and ontology of human-computer interaction

    NARCIS (Netherlands)

    Brey, Philip A.E.

    2005-01-01

    This paper analyzes epistemological and ontological dimensions of Human-Computer Interaction (HCI) through an analysis of the functions of computer systems in relation to their users. It is argued that the primary relation between humans and computer systems has historically been epistemic:

  17. The Yoruba farm market as a communication channel in guinea worm disease surveillance.

    Science.gov (United States)

    Brieger, W R; Kendall, C

    1996-01-01

    Disease eradication programmes are by definition time bound and require strategies that facilitate timely intervention. Surveillance, which undergirds eradication, also requires timely strategies. Finding such strategies is especially challenging when the target disease is endemic in remote areas, e.g. guinea worm disease, the focus of this study. A strategy of market based surveillance was pilot tested in Ifeloju Local Government Area (LGA) of Oyo State, Nigeria. The project goal was to design a surveillance system that both fit into the natural communication network of rural people, and also enlisted their active involvement. Ethnographic research methods were employed to learn about market location, structure, catchment area and attendance pattern. Four larger farm markets (serving 164 hamlets with 17,000 population) were chosen. Each hamlet was visited and a volunteer 'reporter' was recruited. Reporters were trained on case recognition and detection, first aid and prevention, with a sensitivity to distinguishing indigenous and clinical perceptions of guinea worm. The market cycle was based on the traditional four-day week. Field workers visited every second market 16 times between October 1990 and February 1991. The reporter was expected to identify correctly the first case of the season and thus label the village as endemic for the season. Reporters gave oral reports, and positive indications were followed up within 48 hr by field workers, who verified the case and administered first aid. All hamlets were visited once a month to verify negative reports. Reporter attendance was monitored. Those who had a formal role in the market, e.g. sales agents, had better attendance than ordinary farmers who came only to sell their own produce. Knowledge of market structure and attender roles offers a guide for adapting this surveillance approach to other cultural systems and health issues.

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

    Science.gov (United States)

    Mbuagbaw, Lawrence; Thabane, Lehana; Ongolo-Zogo, Pierre

    2013-04-04

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

  19. US Army Weapon Systems Human-Computer Interface (WSHCI) style guide, Version 1

    Energy Technology Data Exchange (ETDEWEB)

    Avery, L.W.; O`Mara, P.A.; Shepard, A.P.

    1996-09-30

    A stated goal of the U.S. Army has been the standardization of the human computer interfaces (HCIS) of its system. Some of the tools being used to accomplish this standardization are HCI design guidelines and style guides. Currently, the Army is employing a number of style guides. While these style guides provide good guidance for the command, control, communications, computers, and intelligence (C4I) domain, they do not necessarily represent the more unique requirements of the Army`s real time and near-real time (RT/NRT) weapon systems. The Office of the Director of Information for Command, Control, Communications, and Computers (DISC4), in conjunction with the Weapon Systems Technical Architecture Working Group (WSTAWG), recognized this need as part of their activities to revise the Army Technical Architecture (ATA). To address this need, DISC4 tasked the Pacific Northwest National Laboratory (PNNL) to develop an Army weapon systems unique HCI style guide. This document, the U.S. Army Weapon Systems Human-Computer Interface (WSHCI) Style Guide, represents the first version of that style guide. The purpose of this document is to provide HCI design guidance for RT/NRT Army systems across the weapon systems domains of ground, aviation, missile, and soldier systems. Each domain should customize and extend this guidance by developing their domain-specific style guides, which will be used to guide the development of future systems within their domains.

  20. Performances of Hybrid Amplitude Shape Modulation for UWB Communications Systems over AWGN Channel in a Single and Multi-User Environment

    Directory of Open Access Journals (Sweden)

    M. Herceg

    2009-09-01

    Full Text Available This paper analyzes the performance of the hybrid Amplitude Shape Modulation (h-ASM scheme for the time-hopping ultra-wideband (TH-UWB communication systems in the single and multi-user environment. h-ASM is the combination of Pulse Amplitude Modulation (PAM and Pulse Shape Modulation (PSM based on modified Hermite pulses (MHP. This scheme is suitable for high rate data transmission applications because b = log2(MN bits can be mapped with one waveform. The channel capacity and error probability over AWGN channel are derived and compared with other modulation schemes.

  1. Choice of Human-Computer Interaction Mode in Stroke Rehabilitation.

    Science.gov (United States)

    Mousavi Hondori, Hossein; Khademi, Maryam; Dodakian, Lucy; McKenzie, Alison; Lopes, Cristina V; Cramer, Steven C

    2016-03-01

    Advances in technology are providing new forms of human-computer interaction. The current study examined one form of human-computer interaction, augmented reality (AR), whereby subjects train in the real-world workspace with virtual objects projected by the computer. Motor performances were compared with those obtained while subjects used a traditional human-computer interaction, that is, a personal computer (PC) with a mouse. Patients used goal-directed arm movements to play AR and PC versions of the Fruit Ninja video game. The 2 versions required the same arm movements to control the game but had different cognitive demands. With AR, the game was projected onto the desktop, where subjects viewed the game plus their arm movements simultaneously, in the same visual coordinate space. In the PC version, subjects used the same arm movements but viewed the game by looking up at a computer monitor. Among 18 patients with chronic hemiparesis after stroke, the AR game was associated with 21% higher game scores (P = .0001), 19% faster reaching times (P = .0001), and 15% less movement variability (P = .0068), as compared to the PC game. Correlations between game score and arm motor status were stronger with the AR version. Motor performances during the AR game were superior to those during the PC game. This result is due in part to the greater cognitive demands imposed by the PC game, a feature problematic for some patients but clinically useful for others. Mode of human-computer interface influences rehabilitation therapy demands and can be individualized for patients. © The Author(s) 2015.

  2. Human computer confluence applied in healthcare and rehabilitation.

    Science.gov (United States)

    Viaud-Delmon, Isabelle; Gaggioli, Andrea; Ferscha, Alois; Dunne, Stephen

    2012-01-01

    Human computer confluence (HCC) is an ambitious research program studying how the emerging symbiotic relation between humans and computing devices can enable radically new forms of sensing, perception, interaction, and understanding. It is an interdisciplinary field, bringing together researches from horizons as various as pervasive computing, bio-signals processing, neuroscience, electronics, robotics, virtual & augmented reality, and provides an amazing potential for applications in medicine and rehabilitation.

  3. An intelligent multi-media human-computer dialogue system

    Science.gov (United States)

    Neal, J. G.; Bettinger, K. E.; Byoun, J. S.; Dobes, Z.; Thielman, C. Y.

    1988-01-01

    Sophisticated computer systems are being developed to assist in the human decision-making process for very complex tasks performed under stressful conditions. The human-computer interface is a critical factor in these systems. The human-computer interface should be simple and natural to use, require a minimal learning period, assist the user in accomplishing his task(s) with a minimum of distraction, present output in a form that best conveys information to the user, and reduce cognitive load for the user. In pursuit of this ideal, the Intelligent Multi-Media Interfaces project is devoted to the development of interface technology that integrates speech, natural language text, graphics, and pointing gestures for human-computer dialogues. The objective of the project is to develop interface technology that uses the media/modalities intelligently in a flexible, context-sensitive, and highly integrated manner modelled after the manner in which humans converse in simultaneous coordinated multiple modalities. As part of the project, a knowledge-based interface system, called CUBRICON (CUBRC Intelligent CONversationalist) is being developed as a research prototype. The application domain being used to drive the research is that of military tactical air control.

  4. Development and utilization of complementary communication channels for treatment decision making and survivorship issues among cancer patients: The CIS Research Consortium Experience.

    Science.gov (United States)

    Fleisher, Linda; Wen, Kuang Yi; Miller, Suzanne M; Diefenbach, Michael; Stanton, Annette L; Ropka, Mary; Morra, Marion; Raich, Peter C

    2015-11-01

    Cancer patients and survivors are assuming active roles in decision-making and digital patient support tools are widely used to facilitate patient engagement. As part of Cancer Information Service Research Consortium's randomized controlled trials focused on the efficacy of eHealth interventions to promote informed treatment decision-making for newly diagnosed prostate and breast cancer patients, and post-treatment breast cancer, we conducted a rigorous process evaluation to examine the actual use of and perceived benefits of two complementary communication channels -- print and eHealth interventions. The three Virtual Cancer Information Service (V-CIS) interventions were developed through a rigorous developmental process, guided by self-regulatory theory, informed decision-making frameworks, and health communications best practices. Control arm participants received NCI print materials; experimental arm participants received the additional V-CIS patient support tool. Actual usage data from the web-based V-CIS was also obtained and reported. Print materials were highly used by all groups. About 60% of the experimental group reported using the V-CIS. Those who did use the V-CIS rated it highly on improvements in knowledge, patient-provider communication and decision-making. The findings show that how patients actually use eHealth interventions either singularly or within the context of other communication channels is complex. Integrating rigorous best practices and theoretical foundations is essential and multiple communication approaches should be considered to support patient preferences.

  5. Long-term exposure to mobile communication radiation: An analysis of time-variability of electric field level in GSM900 down-link channels

    International Nuclear Information System (INIS)

    Miclaus, S.; Bechet, P.; Gheorghevici, M.

    2013-01-01

    Interest for knowing long-term human exposure levels due to mobile communications has increased in the last years. It has been shown that short-term exposure assessment made under standard procedural restrictions is not reliable when it comes to conclusions on long-term exposure levels. The present work is the result of a several week analysis of time variability of electric field level inside traffic and control channels of the GSM900 mobile communication down-link band and it indicates that a temporal model to allow future predictions of exposure on the long run is obtainable. Collecting, processing and statistically analysing the data provide expression of the maximum and weighted field strengths and their evolution in time. Specific electromagnetic footprints of the channels have been extracted, differentiations between their characteristics have been emphasised and practical advice is provided, with the scope of contributing to the development of reliable procedures for long-term exposure assessment. (authors)

  6. Las aventuras de Zamba. Some notes on audiovisual communication in a TV channel for children of the argentinian Ministry of Education

    Directory of Open Access Journals (Sweden)

    Sabina Crivelli

    2015-12-01

    Full Text Available From 2009, within the frame of a process of de-monopolization of audiovisual communication, several public policies were developed in Argentina with the purpose of extending participation in the production of audiovisual contents. In this paper, the main aesthetic qualities of an audiovisual program, Las aventuras de Zamba, produced by a State-run TV channel for children, are analyzed. Some tensions risen in the relationship state / market, producing artistic representations about otherness, are examined.

  7. Program on application of communications satellites to educational development: Design of a 12 channel FM microwave receiver. [color television from communication satellites

    Science.gov (United States)

    Risch, C. O.; Rosenbaum, F. J.; Gregory, R. O.

    1974-01-01

    The design, fabrication, and performance of elements of a low cost FM microwave satellite ground station receiver is described. It is capable of accepting 12 contiguous color television equivalent bandwidth channels in the 11.72 to 12.2 GHz band. Each channel is 40 MHz wide and incorporates a 4 MHz guard band. The modulation format is wideband FM and the channels are frequency division multiplexed. Twelve independent CATV compatible baseband outputs are provided. The overall system specifications are first discussed, then consideration is given to the receiver subsystems and the signal branching network.

  8. Bandwidth enhancement of wireless optical communication link using a near-infrared laser over turbid underwater channel

    KAUST Repository

    Lee, It Ee; Guo, Yujian; Ng, Tien Khee; Park, Kihong; Alouini, Mohamed-Slim; Ooi, Boon S.

    2017-01-01

    Underwater wireless optical communication (UWOC) has been widely studied as a promising alternative to establish reliable short-range marine communication links. Microscopic particulates suspended in various ocean, harbor and natural waters

  9. Human-Computer Interaction, Tourism and Cultural Heritage

    Science.gov (United States)

    Cipolla Ficarra, Francisco V.

    We present a state of the art of the human-computer interaction aimed at tourism and cultural heritage in some cities of the European Mediterranean. In the work an analysis is made of the main problems deriving from training understood as business and which can derail the continuous growth of the HCI, the new technologies and tourism industry. Through a semiotic and epistemological study the current mistakes in the context of the interrelations of the formal and factual sciences will be detected and also the human factors that have an influence on the professionals devoted to the development of interactive systems in order to safeguard and boost cultural heritage.

  10. Stereo Vision for Unrestricted Human-Computer Interaction

    OpenAIRE

    Eldridge, Ross; Rudolph, Heiko

    2008-01-01

    Human computer interfaces have come long way in recent years, but the goal of a computer interpreting unrestricted human movement remains elusive. The use of stereo vision in this field has enabled the development of systems that begin to approach this goal. As computer technology advances we come ever closer to a system that can react to the ambiguities of human movement in real-time. In the foreseeable future stereo computer vision is not likely to replace the keyboard or mouse. There is at...

  11. EOG-sEMG Human Interface for Communication.

    Science.gov (United States)

    Tamura, Hiroki; Yan, Mingmin; Sakurai, Keiko; Tanno, Koichi

    2016-01-01

    The aim of this study is to present electrooculogram (EOG) and surface electromyogram (sEMG) signals that can be used as a human-computer interface. Establishing an efficient alternative channel for communication without overt speech and hand movements is important for increasing the quality of life for patients suffering from amyotrophic lateral sclerosis, muscular dystrophy, or other illnesses. In this paper, we propose an EOG-sEMG human-computer interface system for communication using both cross-channels and parallel lines channels on the face with the same electrodes. This system could record EOG and sEMG signals as "dual-modality" for pattern recognition simultaneously. Although as much as 4 patterns could be recognized, dealing with the state of the patients, we only choose two classes (left and right motion) of EOG and two classes (left blink and right blink) of sEMG which are easily to be realized for simulation and monitoring task. From the simulation results, our system achieved four-pattern classification with an accuracy of 95.1%.

  12. Safety Metrics for Human-Computer Controlled Systems

    Science.gov (United States)

    Leveson, Nancy G; Hatanaka, Iwao

    2000-01-01

    The rapid growth of computer technology and innovation has played a significant role in the rise of computer automation of human tasks in modem production systems across all industries. Although the rationale for automation has been to eliminate "human error" or to relieve humans from manual repetitive tasks, various computer-related hazards and accidents have emerged as a direct result of increased system complexity attributed to computer automation. The risk assessment techniques utilized for electromechanical systems are not suitable for today's software-intensive systems or complex human-computer controlled systems.This thesis will propose a new systemic model-based framework for analyzing risk in safety-critical systems where both computers and humans are controlling safety-critical functions. A new systems accident model will be developed based upon modem systems theory and human cognitive processes to better characterize system accidents, the role of human operators, and the influence of software in its direct control of significant system functions Better risk assessments will then be achievable through the application of this new framework to complex human-computer controlled systems.

  13. Human-computer systems interaction backgrounds and applications 3

    CERN Document Server

    Kulikowski, Juliusz; Mroczek, Teresa; Wtorek, Jerzy

    2014-01-01

    This book contains an interesting and state-of the art collection of papers on the recent progress in Human-Computer System Interaction (H-CSI). It contributes the profound description of the actual status of the H-CSI field and also provides a solid base for further development and research in the discussed area. The contents of the book are divided into the following parts: I. General human-system interaction problems; II. Health monitoring and disabled people helping systems; and III. Various information processing systems. This book is intended for a wide audience of readers who are not necessarily experts in computer science, machine learning or knowledge engineering, but are interested in Human-Computer Systems Interaction. The level of particular papers and specific spreading-out into particular parts is a reason why this volume makes fascinating reading. This gives the reader a much deeper insight than he/she might glean from research papers or talks at conferences. It touches on all deep issues that ...

  14. U.S. Army weapon systems human-computer interface style guide. Version 2

    Energy Technology Data Exchange (ETDEWEB)

    Avery, L.W.; O`Mara, P.A.; Shepard, A.P.; Donohoo, D.T.

    1997-12-31

    A stated goal of the US Army has been the standardization of the human computer interfaces (HCIs) of its system. Some of the tools being used to accomplish this standardization are HCI design guidelines and style guides. Currently, the Army is employing a number of HCI design guidance documents. While these style guides provide good guidance for the command, control, communications, computers, and intelligence (C4I) domain, they do not necessarily represent the more unique requirements of the Army`s real time and near-real time (RT/NRT) weapon systems. The Office of the Director of Information for Command, Control, Communications, and Computers (DISC4), in conjunction with the Weapon Systems Technical Architecture Working Group (WSTAWG), recognized this need as part of their activities to revise the Army Technical Architecture (ATA), now termed the Joint Technical Architecture-Army (JTA-A). To address this need, DISC4 tasked the Pacific Northwest National Laboratory (PNNL) to develop an Army weapon systems unique HCI style guide, which resulted in the US Army Weapon Systems Human-Computer Interface (WSHCI) Style Guide Version 1. Based on feedback from the user community, DISC4 further tasked PNNL to revise Version 1 and publish Version 2. The intent was to update some of the research and incorporate some enhancements. This document provides that revision. The purpose of this document is to provide HCI design guidance for the RT/NRT Army system domain across the weapon systems subdomains of ground, aviation, missile, and soldier systems. Each subdomain should customize and extend this guidance by developing their domain-specific style guides, which will be used to guide the development of future systems within their subdomains.

  15. Coding for optical channels

    CERN Document Server

    Djordjevic, Ivan; Vasic, Bane

    2010-01-01

    This unique book provides a coherent and comprehensive introduction to the fundamentals of optical communications, signal processing and coding for optical channels. It is the first to integrate the fundamentals of coding theory and optical communication.

  16. 75 FR 65323 - The Tennis Channel, Inc. v. Comcast Cable Communications, LLC; File No. CSR-8258-P

    Science.gov (United States)

    2010-10-22

    ... (formerly, Nielsen Media Research). There are 210 DMAs in the United States. In addition to its role as a... Starter tier. 9. In 2005, The Tennis Channel executed an affiliation agreement with Comcast that provided...

  17. Human-computer interface incorporating personal and application domains

    Science.gov (United States)

    Anderson, Thomas G [Albuquerque, NM

    2011-03-29

    The present invention provides a human-computer interface. The interface includes provision of an application domain, for example corresponding to a three-dimensional application. The user is allowed to navigate and interact with the application domain. The interface also includes a personal domain, offering the user controls and interaction distinct from the application domain. The separation into two domains allows the most suitable interface methods in each: for example, three-dimensional navigation in the application domain, and two- or three-dimensional controls in the personal domain. Transitions between the application domain and the personal domain are under control of the user, and the transition method is substantially independent of the navigation in the application domain. For example, the user can fly through a three-dimensional application domain, and always move to the personal domain by moving a cursor near one extreme of the display.

  18. Human-computer interface glove using flexible piezoelectric sensors

    Science.gov (United States)

    Cha, Youngsu; Seo, Jeonggyu; Kim, Jun-Sik; Park, Jung-Min

    2017-05-01

    In this note, we propose a human-computer interface glove based on flexible piezoelectric sensors. We select polyvinylidene fluoride as the piezoelectric material for the sensors because of advantages such as a steady piezoelectric characteristic and good flexibility. The sensors are installed in a fabric glove by means of pockets and Velcro bands. We detect changes in the angles of the finger joints from the outputs of the sensors, and use them for controlling a virtual hand that is utilized in virtual object manipulation. To assess the sensing ability of the piezoelectric sensors, we compare the processed angles from the sensor outputs with the real angles from a camera recoding. With good agreement between the processed and real angles, we successfully demonstrate the user interaction system with the virtual hand and interface glove based on the flexible piezoelectric sensors, for four hand motions: fist clenching, pinching, touching, and grasping.

  19. A structural approach to constructing perspective efficient and reliable human-computer interfaces

    International Nuclear Information System (INIS)

    Balint, L.

    1989-01-01

    The principles of human-computer interface (HCI) realizations are investigated with the aim of getting closer to a general framework and thus, to a more or less solid background of constructing perspective efficient, reliable and cost-effective human-computer interfaces. On the basis of characterizing and classifying the different HCI solutions, the fundamental problems of interface construction are pointed out especially with respect to human error occurrence possibilities. The evolution of HCI realizations is illustrated by summarizing the main properties of past, present and foreseeable future interface generations. HCI modeling is pointed out to be a crucial problem in theoretical and practical investigations. Suggestions concerning HCI structure (hierarchy and modularity), HCI functional dynamics (mapping from input to output information), minimization of human error caused system failures (error-tolerance, error-recovery and error-correcting) as well as cost-effective HCI design and realization methodology (universal and application-oriented vs. application-specific solutions) are presented. The concept of RISC-based and SCAMP-type HCI components is introduced with the aim of having a reduced interaction scheme in communication and a well defined architecture in HCI components' internal structure. HCI efficiency and reliability are dealt with, by taking into account complexity and flexibility. The application of fast computerized prototyping is also briefly investigated as an experimental device of achieving simple, parametrized, invariant HCI models. Finally, a concise outline of an approach of how to construct ideal HCI's is also suggested by emphasizing the open questions and the need of future work related to the proposals, as well. (author). 14 refs, 6 figs

  20. Scheduling and Control of Multi-Node Mobile Communications Systems With Randomly-Varying Channels by Stability Methods

    National Research Council Canada - National Science Library

    Kushner, Harold J

    2005-01-01

    We consider a communications network consisting of many mobiles. There are random external data processes arriving at some of the mobiles, each destined for a unique destination or set of destinations...

  1. CHANNEL ESTIMATION TECHNIQUE

    DEFF Research Database (Denmark)

    2015-01-01

    A method includes determining a sequence of first coefficient estimates of a communication channel based on a sequence of pilots arranged according to a known pilot pattern and based on a receive signal, wherein the receive signal is based on the sequence of pilots transmitted over the communicat......A method includes determining a sequence of first coefficient estimates of a communication channel based on a sequence of pilots arranged according to a known pilot pattern and based on a receive signal, wherein the receive signal is based on the sequence of pilots transmitted over...... the communication channel. The method further includes determining a sequence of second coefficient estimates of the communication channel based on a decomposition of the first coefficient estimates in a dictionary matrix and a sparse vector of the second coefficient estimates, the dictionary matrix including...... filter characteristics of at least one known transceiver filter arranged in the communication channel....

  2. Study of Channel Characteristics for Galvanic-Type Intra-Body Communication Based on a Transfer Function from a Quasi-Static Field Model

    Directory of Open Access Journals (Sweden)

    Min Du

    2012-11-01

    Full Text Available Intra-Body Communication (IBC, which modulates ionic currents over the human body as the communication medium, offers a low power and reliable signal transmission method for information exchange across the body. This paper first briefly reviews the quasi-static electromagnetic (EM field modeling for a galvanic-type IBC human limb operating below 1 MHz and obtains the corresponding transfer function with correction factor using minimum mean square error (MMSE technique. Then, the IBC channel characteristics are studied through the comparison between theoretical calculations via this transfer function and experimental measurements in both frequency domain and time domain. High pass characteristics are obtained in the channel gain analysis versus different transmission distances. In addition, harmonic distortions are analyzed in both baseband and passband transmissions for square input waves. The experimental results are consistent with the calculation results from the transfer function with correction factor. Furthermore, we also explore both theoretical and simulation results for the bit-error-rate (BER performance of several common modulation schemes in the IBC system with a carrier frequency of 500 kHz. It is found that the theoretical results are in good agreement with the simulation results.

  3. A Novel Feature Optimization for Wearable Human-Computer Interfaces Using Surface Electromyography Sensors

    Directory of Open Access Journals (Sweden)

    Han Sun

    2018-03-01

    Full Text Available The novel human-computer interface (HCI using bioelectrical signals as input is a valuable tool to improve the lives of people with disabilities. In this paper, surface electromyography (sEMG signals induced by four classes of wrist movements were acquired from four sites on the lower arm with our designed system. Forty-two features were extracted from the time, frequency and time-frequency domains. Optimal channels were determined from single-channel classification performance rank. The optimal-feature selection was according to a modified entropy criteria (EC and Fisher discrimination (FD criteria. The feature selection results were evaluated by four different classifiers, and compared with other conventional feature subsets. In online tests, the wearable system acquired real-time sEMG signals. The selected features and trained classifier model were used to control a telecar through four different paradigms in a designed environment with simple obstacles. Performance was evaluated based on travel time (TT and recognition rate (RR. The results of hardware evaluation verified the feasibility of our acquisition systems, and ensured signal quality. Single-channel analysis results indicated that the channel located on the extensor carpi ulnaris (ECU performed best with mean classification accuracy of 97.45% for all movement’s pairs. Channels placed on ECU and the extensor carpi radialis (ECR were selected according to the accuracy rank. Experimental results showed that the proposed FD method was better than other feature selection methods and single-type features. The combination of FD and random forest (RF performed best in offline analysis, with 96.77% multi-class RR. Online results illustrated that the state-machine paradigm with a 125 ms window had the highest maneuverability and was closest to real-life control. Subjects could accomplish online sessions by three sEMG-based paradigms, with average times of 46.02, 49.06 and 48.08 s

  4. Performance analysis of multihop heterodyne free-space optical communication over general Malaga turbulence channels with pointing error

    KAUST Repository

    Alheadary, Wael Ghazy

    2017-09-21

    This work investigates the end-to-end performance of a free space optical amplify-and-forward (AF) channel-state-information (CSI)-assisted relaying system using heterodyne detection over Malaga turbulence channels at the presence of pointing error employing rectangular quadrature amplitude modulation (R-QAM). More specifically, we present exact closed-form expressions for average bit-error rate for adaptive/non-adaptive modulation, achievable spectral efficiency, and ergodic capacity by utilizing generalized power series of Meijer\\'s G-function. Moreover, asymptotic closed form expressions are provided to validate our work at high power regime. In addition, all the presented analytical results are illustrated using a selected set of numerical results. Moreover, we applied the bisection method to find the optimum beam width for the proposed FSO system.

  5. Institutionalizing human-computer interaction for global health.

    Science.gov (United States)

    Gulliksen, Jan

    2017-06-01

    Digitalization is the societal change process in which new ICT-based solutions bring forward completely new ways of doing things, new businesses and new movements in the society. Digitalization also provides completely new ways of addressing issues related to global health. This paper provides an overview of the field of human-computer interaction (HCI) and in what way the field has contributed to international development in different regions of the world. Additionally, it outlines the United Nations' new sustainability goals from December 2015 and what these could contribute to the development of global health and its relationship to digitalization. Finally, it argues why and how HCI could be adopted and adapted to fit the contextual needs, the need for localization and for the development of new digital innovations. The research methodology is mostly qualitative following an action research paradigm in which the actual change process that the digitalization is evoking is equally important as the scientific conclusions that can be drawn. In conclusion, the paper argues that digitalization is fundamentally changing the society through the development and use of digital technologies and may have a profound effect on the digital development of every country in the world. But it needs to be developed based on local practices, it needs international support and to not be limited by any technological constraints. Particularly digitalization to support global health requires a profound understanding of the users and their context, arguing for user-centred systems design methodologies as particularly suitable.

  6. Overview Electrotactile Feedback for Enhancing Human Computer Interface

    Science.gov (United States)

    Pamungkas, Daniel S.; Caesarendra, Wahyu

    2018-04-01

    To achieve effective interaction between a human and a computing device or machine, adequate feedback from the computing device or machine is required. Recently, haptic feedback is increasingly being utilised to improve the interactivity of the Human Computer Interface (HCI). Most existing haptic feedback enhancements aim at producing forces or vibrations to enrich the user’s interactive experience. However, these force and/or vibration actuated haptic feedback systems can be bulky and uncomfortable to wear and only capable of delivering a limited amount of information to the user which can limit both their effectiveness and the applications they can be applied to. To address this deficiency, electrotactile feedback is used. This involves delivering haptic sensations to the user by electrically stimulating nerves in the skin via electrodes placed on the surface of the skin. This paper presents a review and explores the capability of electrotactile feedback for HCI applications. In addition, a description of the sensory receptors within the skin for sensing tactile stimulus and electric currents alsoseveral factors which influenced electric signal to transmit to the brain via human skinare explained.

  7. The Past, Present and Future of Human Computer Interaction

    KAUST Repository

    Churchill, Elizabeth

    2018-01-16

    Human Computer Interaction (HCI) focuses on how people interact with, and are transformed by computation. Our current technology landscape is changing rapidly. Interactive applications, devices and services are increasingly becoming embedded into our environments. From our homes to the urban and rural spaces, we traverse everyday. We are increasingly able toヨoften required toヨmanage and configure multiple, interconnected devices and program their interactions. Artificial intelligence (AI) techniques are being used to create dynamic services that learn about us and others, that make conclusions about our intents and affiliations, and that mould our digital interactions based in predictions about our actions and needs, nudging us toward certain behaviors. Computation is also increasingly embedded into our bodies. Understanding human interactions in the everyday digital and physical context. During this lecture, Elizabeth Churchill -Director of User Experience at Google- will talk about how an emerging landscape invites us to revisit old methods and tactics for understanding how people interact with computers and computation, and how it challenges us to think about new methods and frameworks for understanding the future of human-centered computation.

  8. On the performance of free-space optical wireless communication systems over double generalized gamma fading channels

    KAUST Repository

    Al-Quwaiee, Hessa

    2014-03-01

    Starting with the double generalized Gamma (GG) model that was proposed in [1] to describe turbulence-induced fading in free-space optical (FSO) systems, we propose a new unified model which accounts for the impact of pointing errors and type of receiver detector. Based on this new unified model, we study the performance of FSO links operating over these kind of channels. All our analytical results are verified using computer based Monte-Carlo simulations. © 2014 IEEE.

  9. On the performance of free-space optical wireless communication systems over double generalized gamma fading channels

    KAUST Repository

    Al-Quwaiee, Hessa; Ansari, Imran Shafique; Alouini, Mohamed-Slim

    2014-01-01

    Starting with the double generalized Gamma (GG) model that was proposed in [1] to describe turbulence-induced fading in free-space optical (FSO) systems, we propose a new unified model which accounts for the impact of pointing errors and type of receiver detector. Based on this new unified model, we study the performance of FSO links operating over these kind of channels. All our analytical results are verified using computer based Monte-Carlo simulations. © 2014 IEEE.

  10. Experimental Investigation of Subject-Specific On-Body Radio Propagation Channels for Body-Centric Wireless Communications

    Directory of Open Access Journals (Sweden)

    Mohammad Monirujjaman Khan

    2014-01-01

    Full Text Available In this paper, subject-specific narrowband (2.45 GHz and ultra-wideband (3–10.6 GHz on-body radio propagation studies in wireless body area networks (WBANs were performed by characterizing the path loss for eight different human subjects of different shapes and sizes. The body shapes and sizes of the test subjects used in this study are characterised as thin, medium build, fatty, shorter, average height and taller. Experimental investigation was made in an indoor environment using a pair of printed monopoles (for the narrowband case and a pair of tapered slot antennas (for the ultra-wideband (UWB case. Results demonstrated that, due to the different sizes, heights and shapes of the test subjects, the path loss exponent value varies up to maximum of 0.85 for the narrowband on-body case, whereas a maximum variation of the path loss exponent value of 1.15 is noticed for the UWB case. In addition, the subject-specific behaviour of the on-body radio propagation channels was compared between narrowband and UWB systems, and it was deduced that the on-body radio channels are subject-specific for both narrowband and UWB system cases, when the same antennas (same characteristics are used. The effect of the human body shape and size variations on the eight different on-body radio channels is also studied for both the narrowband and UWB cases.

  11. A novel unified expression for the capacity and bit error probability of wireless communication systems over generalized fading channels

    KAUST Repository

    Yilmaz, Ferkan; Alouini, Mohamed-Slim

    2012-01-01

    function (MGF)-based unified expression for the ABEP and AC of single and multiple link communications with maximal ratio combining. In addition, this paper proposes the hyper-Fox's H fading model as a unified fading distribution of a majority of the well

  12. Construction and Design Kits: Human Problem-Domain Communication

    National Research Council Canada - National Science Library

    Fischer, Gerhard; Lemke, Andreas C

    1987-01-01

    .... To provide the user with the appropriate level of control and a better understanding, we have to replace human-computer communication with human problem-domain communication, which allows users...

  13. COMMUNICATIONS

    CERN Multimedia

    L. Taylor and D. Barney

    2010-01-01

    CMS Centres, Outreach and the 7 TeV Media Event The new CMS Communications group is now established and is addressing three areas that are critical to CMS as it enters the physics operations phase: - Communications Infrastructure, including almost 50 CMS Centres Worldwide, videoconferencing systems, and CERN meeting rooms - Information systems, including the internal and external Web sites as well as the document preparation and management systems - Outreach and Education activities, including working with print, radio and TV media, visits to CMS, and exhibitions. The group has been active in many areas, with the highest priority being accorded to needs of CMS operations and preparations for the major media event planned for 7 TeV collisions. Unfortunately the CMS Centre@CERN suffered a major setback when, on 21st December, a cooling water pipe froze and burst on the floor above the CMS Centre main room. Water poured through the ceiling, flooding the floor and soaking some of the consoles, before e...

  14. COMMUNICATIONS

    CERN Multimedia

    A. Petrilli

    2013-01-01

    The organisation of the Open Days at the end of September was the single biggest effort of the CMS Communications Group this year. We would like to thank all volunteers for their hard work to show our Point 5 facilities and explain science and technology to the general public. During two days more than 5,000 people visited the CMS detector underground and profited from the surface activities, which included an exhibition on CMS, a workshop on superconductivity, and an activity for our younger visitors involving wooden Kapla blocks. The Communications Group took advantage of the preparations to produce new CMS posters that can be reused at other venues. Event display images have been produced not just for this occasion but also for other exhibits, education purposes, publications etc. During the Open Days, Gilles Jobin, 2012 winner of CERN Collide@CERN prize, performed his Quantum show in Point 5, with the light installation of German artist Julius von Bismarck. Image 3: CERN Open Days at CMS wel...

  15. Bit error rate analysis of free-space optical communication over general Malaga turbulence channels with pointing error

    KAUST Repository

    Alheadary, Wael Ghazy

    2016-12-24

    In this work, we present a bit error rate (BER) and achievable spectral efficiency (ASE) performance of a freespace optical (FSO) link with pointing errors based on intensity modulation/direct detection (IM/DD) and heterodyne detection over general Malaga turbulence channel. More specifically, we present exact closed-form expressions for adaptive and non-adaptive transmission. The closed form expressions are presented in terms of generalized power series of the Meijer\\'s G-function. Moreover, asymptotic closed form expressions are provided to validate our work. In addition, all the presented analytical results are illustrated using a selected set of numerical results.

  16. Understanding consumer preferences for communication channels to create consumer-directed health promotion efforts in psychiatric rehabilitation settings.

    Science.gov (United States)

    DiFranco, Evelina; Bressi, Sara K; Salzer, Mark S

    2006-01-01

    People with serious mental illnesses experience increased rates of physical illnesses. Drop-in centers and psychosocial rehabilitation programs can serve as important settings for health promotion efforts, but such efforts should utilize communication strategies that are used by consumers and are perceived to be reliable. Focus groups involving 23 consumers at drop-in centers in Philadelphia were conducted to assess the perceived usefulness of health information from a variety of sources. Consumers especially liked getting information from other people, including health care professionals, friends, and family, and found the information to be reliable and useful. Print literature, the Internet, and a library had various limitations. Respondents were generally unfamiliar with community health fairs and related events. Consumers considered trustworthiness, proximity and availability, and the specificity and depth of information provided by a communication source when getting health information. Implications for health promotion efforts are discussed.

  17. Spatially multiplexed orbital-angular-momentum-encoded single photon and classical channels in a free-space optical communication link.

    Science.gov (United States)

    Ren, Yongxiong; Liu, Cong; Pang, Kai; Zhao, Jiapeng; Cao, Yinwen; Xie, Guodong; Li, Long; Liao, Peicheng; Zhao, Zhe; Tur, Moshe; Boyd, Robert W; Willner, Alan E

    2017-12-01

    We experimentally demonstrate spatial multiplexing of an orbital angular momentum (OAM)-encoded quantum channel and a classical Gaussian beam with a different wavelength and orthogonal polarization. Data rates as large as 100 MHz are achieved by encoding on two different OAM states by employing a combination of independently modulated laser diodes and helical phase holograms. The influence of OAM mode spacing, encoding bandwidth, and interference from the co-propagating Gaussian beam on registered photon count rates and quantum bit error rates is investigated. Our results show that the deleterious effects of intermodal crosstalk effects on system performance become less important for OAM mode spacing Δ≥2 (corresponding to a crosstalk value of less than -18.5  dB). The use of OAM domain can additionally offer at least 10.4 dB isolation besides that provided by wavelength and polarization, leading to a further suppression of interference from the classical channel.

  18. MPEG-compliant joint source/channel coding using discrete cosine transform and substream scheduling for visual communication over packet networks

    Science.gov (United States)

    Kim, Seong-Whan; Suthaharan, Shan; Lee, Heung-Kyu; Rao, K. R.

    2001-01-01

    Quality of Service (QoS)-guarantee in real-time communication for multimedia applications is significantly important. An architectural framework for multimedia networks based on substreams or flows is effectively exploited for combining source and channel coding for multimedia data. But the existing frame by frame approach which includes Moving Pictures Expert Group (MPEG) cannot be neglected because it is a standard. In this paper, first, we designed an MPEG transcoder which converts an MPEG coded stream into variable rate packet sequences to be used for our joint source/channel coding (JSCC) scheme. Second, we designed a classification scheme to partition the packet stream into multiple substreams which have their own QoS requirements. Finally, we designed a management (reservation and scheduling) scheme for substreams to support better perceptual video quality such as the bound of end-to-end jitter. We have shown that our JSCC scheme is better than two other two popular techniques by simulation and real video experiments on the TCP/IP environment.

  19. An Accurate Computational Tool for Performance Estimation of FSO Communication Links over Weak to Strong Atmospheric Turbulent Channels

    Directory of Open Access Journals (Sweden)

    Theodore D. Katsilieris

    2017-03-01

    Full Text Available The terrestrial optical wireless communication links have attracted significant research and commercial worldwide interest over the last few years due to the fact that they offer very high and secure data rate transmission with relatively low installation and operational costs, and without need of licensing. However, since the propagation path of the information signal, i.e., the laser beam, is the atmosphere, their effectivity affects the atmospheric conditions strongly in the specific area. Thus, system performance depends significantly on the rain, the fog, the hail, the atmospheric turbulence, etc. Due to the influence of these effects, it is necessary to study, theoretically and numerically, very carefully before the installation of such a communication system. In this work, we present exactly and accurately approximate mathematical expressions for the estimation of the average capacity and the outage probability performance metrics, as functions of the link’s parameters, the transmitted power, the attenuation due to the fog, the ambient noise and the atmospheric turbulence phenomenon. The latter causes the scintillation effect, which results in random and fast fluctuations of the irradiance at the receiver’s end. These fluctuations can be studied accurately with statistical methods. Thus, in this work, we use either the lognormal or the gamma–gamma distribution for weak or moderate to strong turbulence conditions, respectively. Moreover, using the derived mathematical expressions, we design, accomplish and present a computational tool for the estimation of these systems’ performances, while also taking into account the parameter of the link and the atmospheric conditions. Furthermore, in order to increase the accuracy of the presented tool, for the cases where the obtained analytical mathematical expressions are complex, the performance results are verified with the numerical estimation of the appropriate integrals. Finally, using

  20. USING OLFACTORY DISPLAYS AS A NONTRADITIONAL INTERFACE IN HUMAN COMPUTER INTERACTION

    Directory of Open Access Journals (Sweden)

    Alper Efe

    2017-07-01

    Full Text Available Smell has its limitations and disadvantages as a display medium, but it also has its strengths and many have recognized its potential. At present, in communications and virtual technologies, smell is either forgotten or improperly stimulated, because non controlled odorants present in the physical space surrounding the user. Nonetheless a controlled presentation of olfactory information can give advantages in various application fields. Therefore, two enabling technologies, electronic noses and especially olfactory displays are reviewed. Scenarios of usage are discussed together with relevant psycho-physiological issues. End-to-end systems including olfactory interfaces are quantitatively characterised under many respects. Recent works done by the authors on field are reported. The article will touch briefly on the control of scent emissions; an important factor to consider when building scented computer systems. As a sample application SUBSMELL system investigated. A look at areas of human computer interaction where olfaction output may prove useful will be presented. The article will finish with some brief conclusions and discuss some shortcomings and gaps of the topic. In particular, the addition of olfactory cues to a virtual environment increased the user's sense of presence and memory of the environment. Also, this article discusses the educational aspect of the subsmell systems.

  1. Eye Tracking Based Control System for Natural Human-Computer Interaction

    Directory of Open Access Journals (Sweden)

    Xuebai Zhang

    2017-01-01

    Full Text Available Eye movement can be regarded as a pivotal real-time input medium for human-computer communication, which is especially important for people with physical disability. In order to improve the reliability, mobility, and usability of eye tracking technique in user-computer dialogue, a novel eye control system with integrating both mouse and keyboard functions is proposed in this paper. The proposed system focuses on providing a simple and convenient interactive mode by only using user’s eye. The usage flow of the proposed system is designed to perfectly follow human natural habits. Additionally, a magnifier module is proposed to allow the accurate operation. In the experiment, two interactive tasks with different difficulty (searching article and browsing multimedia web were done to compare the proposed eye control tool with an existing system. The Technology Acceptance Model (TAM measures are used to evaluate the perceived effectiveness of our system. It is demonstrated that the proposed system is very effective with regard to usability and interface design.

  2. Eye Tracking Based Control System for Natural Human-Computer Interaction.

    Science.gov (United States)

    Zhang, Xuebai; Liu, Xiaolong; Yuan, Shyan-Ming; Lin, Shu-Fan

    2017-01-01

    Eye movement can be regarded as a pivotal real-time input medium for human-computer communication, which is especially important for people with physical disability. In order to improve the reliability, mobility, and usability of eye tracking technique in user-computer dialogue, a novel eye control system with integrating both mouse and keyboard functions is proposed in this paper. The proposed system focuses on providing a simple and convenient interactive mode by only using user's eye. The usage flow of the proposed system is designed to perfectly follow human natural habits. Additionally, a magnifier module is proposed to allow the accurate operation. In the experiment, two interactive tasks with different difficulty (searching article and browsing multimedia web) were done to compare the proposed eye control tool with an existing system. The Technology Acceptance Model (TAM) measures are used to evaluate the perceived effectiveness of our system. It is demonstrated that the proposed system is very effective with regard to usability and interface design.

  3. Bandwidth enhancement of wireless optical communication link using a near-infrared laser over turbid underwater channel

    KAUST Repository

    Lee, It Ee

    2017-11-30

    Underwater wireless optical communication (UWOC) has been widely studied as a promising alternative to establish reliable short-range marine communication links. Microscopic particulates suspended in various ocean, harbor and natural waters will alter the propagation characteristics of the optical signals underwater. In this paper, we demonstrate a gigabit near-infrared (NIR)-based UWOC link using an 808-nm laser diode, to examine the feasibility of the proposed system in mitigating the particle scattering effect over turbid waters. We show that the NIR wavelengths presents greater resilience to the aqueous suspension of these micro-sized particles with a smaller scattering effect due to its longer wavelength, as evident by the smaller variations in the optical beam transmittance. It is also observed that the error performance is improved at higher concentrations albeit the significant reduction in received signal power. We further demonstrate that the overall frequency response of the system exhibits a bandwidth enhancement up to a few tens of MHz with increasing concentrations.

  4. Statistical Modelling and Characterization of Experimental mm-Wave Indoor Channels for Future 5G Wireless Communication Networks.

    Science.gov (United States)

    Al-Samman, A M; Rahman, T A; Azmi, M H; Hindia, M N; Khan, I; Hanafi, E

    This paper presents an experimental characterization of millimeter-wave (mm-wave) channels in the 6.5 GHz, 10.5 GHz, 15 GHz, 19 GHz, 28 GHz and 38 GHz frequency bands in an indoor corridor environment. More than 4,000 power delay profiles were measured across the bands using an omnidirectional transmitter antenna and a highly directional horn receiver antenna for both co- and cross-polarized antenna configurations. This paper develops a new path-loss model to account for the frequency attenuation with distance, which we term the frequency attenuation (FA) path-loss model and introduce a frequency-dependent attenuation factor. The large-scale path loss was characterized based on both new and well-known path-loss models. A general and less complex method is also proposed to estimate the cross-polarization discrimination (XPD) factor of close-in reference distance with the XPD (CIX) and ABG with the XPD (ABGX) path-loss models to avoid the computational complexity of minimum mean square error (MMSE) approach. Moreover, small-scale parameters such as root mean square (RMS) delay spread, mean excess (MN-EX) delay, dispersion factors and maximum excess (MAX-EX) delay parameters were used to characterize the multipath channel dispersion. Multiple statistical distributions for RMS delay spread were also investigated. The results show that our proposed models are simpler and more physically-based than other well-known models. The path-loss exponents for all studied models are smaller than that of the free-space model by values in the range of 0.1 to 1.4 for all measured frequencies. The RMS delay spread values varied between 0.2 ns and 13.8 ns, and the dispersion factor values were less than 1 for all measured frequencies. The exponential and Weibull probability distribution models best fit the RMS delay spread empirical distribution for all of the measured frequencies in all scenarios.

  5. Relay-aided free-space optical communications using α - μ distribution over atmospheric turbulence channels with misalignment errors

    Science.gov (United States)

    Upadhya, Abhijeet; Dwivedi, Vivek K.; Singh, G.

    2018-06-01

    In this paper, we have analyzed the performance of dual hop radio frequency (RF)/free-space optical (FSO) fixed gain relay environment confined by atmospheric turbulence induced fading channel over FSO link and modeled using α - μ distribution. The RF hop of the amplify-and-forward scheme undergoes the Rayleigh fading and the proposed system model also considers the pointing error effect on the FSO link. A novel and accurate mathematical expression of the probability density function for a FSO link experiencing α - μ distributed atmospheric turbulence in the presence of pointing error is derived. Further, we have presented analytical expressions of outage probability and bit error rate in terms of Meijer-G function. In addition to this, a useful and mathematically tractable closed-form expression for the end-to-end ergodic capacity of the dual hop scheme in terms of bivariate Fox's H function is derived. The atmospheric turbulence, misalignment errors and various binary modulation schemes for intensity modulation on optical wireless link are considered to yield the results. Finally, we have analyzed each of the three performance metrics for high SNR in order to represent them in terms of elementary functions and the achieved analytical results are supported by computer-based simulations.

  6. HIPPI and Fibre Channel

    International Nuclear Information System (INIS)

    Tolmie, D.E.

    1992-01-01

    The High-Performance Parallel Interface (HIPPI) and Fibre Channel are near-gigabit per second data communications interfaces being developed in ANSI standards Task Group X3T9.3. HIPPI is the current interface of choice in the high-end and supercomputer arena, and Fibre Channel is a follow-on effort. HIPPI came from a local area network background, and Fibre Channel came from a mainframe to peripheral interface background

  7. Channel Modeling

    Science.gov (United States)

    Schmitz, Arne; Schinnenburg, Marc; Gross, James; Aguiar, Ana

    For any communication system the Signal-to-Interference-plus-Noise-Ratio of the link is a fundamental metric. Recall (cf. Chapter 9) that the SINR is defined as the ratio between the received power of the signal of interest and the sum of all "disturbing" power sources (i.e. interference and noise). From information theory it is known that a higher SINR increases the maximum possible error-free transmission rate (referred to as Shannon capacity [417] of any communication system and vice versa). Conversely, the higher the SINR, the lower will be the bit error rate in practical systems. While one aspect of the SINR is the sum of all distracting power sources, another issue is the received power. This depends on the transmitted power, the used antennas, possibly on signal processing techniques and ultimately on the channel gain between transmitter and receiver.

  8. Capacity of optical communications over a lossy bosonic channel with a receiver employing the most general coherent electro-optic feedback control

    Science.gov (United States)

    Chung, Hye Won; Guha, Saikat; Zheng, Lizhong

    2017-07-01

    We study the problem of designing optical receivers to discriminate between multiple coherent states using coherent processing receivers—i.e., one that uses arbitrary coherent feedback control and quantum-noise-limited direct detection—which was shown by Dolinar to achieve the minimum error probability in discriminating any two coherent states. We first derive and reinterpret Dolinar's binary-hypothesis minimum-probability-of-error receiver as the one that optimizes the information efficiency at each time instant, based on recursive Bayesian updates within the receiver. Using this viewpoint, we propose a natural generalization of Dolinar's receiver design to discriminate M coherent states, each of which could now be a codeword, i.e., a sequence of N coherent states, each drawn from a modulation alphabet. We analyze the channel capacity of the pure-loss optical channel with a general coherent-processing receiver in the low-photon number regime and compare it with the capacity achievable with direct detection and the Holevo limit (achieving the latter would require a quantum joint-detection receiver). We show compelling evidence that despite the optimal performance of Dolinar's receiver for the binary coherent-state hypothesis test (either in error probability or mutual information), the asymptotic communication rate achievable by such a coherent-processing receiver is only as good as direct detection. This suggests that in the infinitely long codeword limit, all potential benefits of coherent processing at the receiver can be obtained by designing a good code and direct detection, with no feedback within the receiver.

  9. A Human/Computer Learning Network to Improve Biodiversity Conservation and Research

    OpenAIRE

    Kelling, Steve; Gerbracht, Jeff; Fink, Daniel; Lagoze, Carl; Wong, Weng-Keen; Yu, Jun; Damoulas, Theodoros; Gomes, Carla

    2012-01-01

    In this paper we describe eBird, a citizen-science project that takes advantage of the human observational capacity to identify birds to species, which is then used to accurately represent patterns of bird occurrences across broad spatial and temporal extents. eBird employs artificial intelligence techniques such as machine learning to improve data quality by taking advantage of the synergies between human computation and mechanical computation. We call this a Human-Computer Learning Network,...

  10. From Human-Computer Interaction to Human-Robot Social Interaction

    OpenAIRE

    Toumi, Tarek; Zidani, Abdelmadjid

    2014-01-01

    Human-Robot Social Interaction became one of active research fields in which researchers from different areas propose solutions and directives leading robots to improve their interactions with humans. In this paper we propose to introduce works in both human robot interaction and human computer interaction and to make a bridge between them, i.e. to integrate emotions and capabilities concepts of the robot in human computer model to become adequate for human robot interaction and discuss chall...

  11. My4Sight: A Human Computation Platform for Improving Flu Predictions

    OpenAIRE

    Akupatni, Vivek Bharath

    2015-01-01

    While many human computation (human-in-the-loop) systems exist in the field of Artificial Intelligence (AI) to solve problems that can't be solved by computers alone, comparatively fewer platforms exist for collecting human knowledge, and evaluation of various techniques for harnessing human insights in improving forecasting models for infectious diseases, such as Influenza and Ebola. In this thesis, we present the design and implementation of My4Sight, a human computation system develope...

  12. Virtual reality/ augmented reality technology : the next chapter of human-computer interaction

    OpenAIRE

    Huang, Xing

    2015-01-01

    No matter how many different size and shape the computer has, the basic components of computers are still the same. If we use the user perspective to look for the development of computer history, we can surprisingly find that it is the input output device that leads the development of the industry development, in one word, human-computer interaction changes the development of computer history. Human computer interaction has been gone through three stages, the first stage relies on the inpu...

  13. Identifying Error in AUV Communication

    National Research Council Canada - National Science Library

    Coleman, Joseph; Merrill, Kaylani; O'Rourke, Michael; Rajala, Andrew G; Edwards, Dean B

    2006-01-01

    Mine Countermeasures (MCM) involving Autonomous Underwater Vehicles (AUVs) are especially susceptible to error, given the constraints on underwater acoustic communication and the inconstancy of the underwater communication channel...

  14. Situated dialog in speech-based human-computer interaction

    CERN Document Server

    Raux, Antoine; Lane, Ian; Misu, Teruhisa

    2016-01-01

    This book provides a survey of the state-of-the-art in the practical implementation of Spoken Dialog Systems for applications in everyday settings. It includes contributions on key topics in situated dialog interaction from a number of leading researchers and offers a broad spectrum of perspectives on research and development in the area. In particular, it presents applications in robotics, knowledge access and communication and covers the following topics: dialog for interacting with robots; language understanding and generation; dialog architectures and modeling; core technologies; and the analysis of human discourse and interaction. The contributions are adapted and expanded contributions from the 2014 International Workshop on Spoken Dialog Systems (IWSDS 2014), where researchers and developers from industry and academia alike met to discuss and compare their implementation experiences, analyses and empirical findings.

  15. Convergence of calls as animals form social bonds, active compensation for noisy communication channels, and the evolution of vocal learning in mammals.

    Science.gov (United States)

    Tyack, Peter L

    2008-08-01

    The classic evidence for vocal production learning involves imitation of novel, often anthropogenic sounds. Among mammals, this has been reported for dolphins, elephants, harbor seals, and humans. A broader taxonomic distribution has been reported for vocal convergence, where the acoustic properties of calls from different individuals converge when they are housed together in captivity or form social bonds in the wild. Vocal convergence has been demonstrated for animals as diverse as songbirds, parakeets, hummingbirds, bats, elephants, cetaceans, and primates. For most species, call convergence is thought to reflect a group-distinctive identifier, with shared calls reflecting and strengthening social bonds. A ubiquitous function for vocal production learning that is starting to receive attention involves modifying signals to improve communication in a noisy channel. Pooling data on vocal imitation, vocal convergence, and compensation for noise suggests a wider taxonomic distribution of vocal production learning among mammals than has been generally appreciated. The wide taxonomic distribution of this evidence for vocal production learning suggests that perhaps more of the neural underpinnings for vocal production learning are in place in mammals than is usually recognized. (c) 2008 APA, all rights reserved

  16. Development of an asynchronous communication channel between wireless sensor nodes, smartphone devices, and web applications using RESTful Web Services for intelligent farming

    Science.gov (United States)

    De Leon, Marlene M.; Estuar, Maria Regina E.; Lim, Hadrian Paulo; Victorino, John Noel C.; Co, Jerelyn; Saddi, Ivan Lester; Paelmo, Sharlene Mae; Dela Cruz, Bon Lemuel

    2017-09-01

    Environment and agriculture related applications have been gaining ground for the past several years and have been the context for researches in ubiquitous and pervasive computing. This study is a part of a bigger study that uses artificial intelligence in developing models to detect, monitor, and forecast the spread of Fusarium oxysporum cubense TR4 (FOC TR4) on Cavendish bananas cultivated in the Philippines. To implement an Intelligent Farming system, 1) wireless sensor nodes (WSNs) are deployed in Philippine banana plantations to collect soil parameter data that is considered to affect the health of Cavendish bananas, 2) a custom built smartphone application is used for collecting, storing, and transmitting soil data, plant images and plant status data to a cloud storage, and 3) a custom built web application is used to load and display results of physico-chemical analysis of soil, analysis of data models, and geographic locations of plants being monitored. This study discusses the issues, considerations, and solutions implemented in the development of an asynchronous communication channel to ensure that all data collected by WSNs and smartphone applications are transmitted with a high degree of accuracy and reliability. From a design standpoint: standard API documentation on usage of data type is required to avoid inconsistencies in parameter passing. From a technical standpoint, there is a need to include error-handling mechanisms especially for delays in transmission of data as well as generalize method of parsing thru multidimensional array of data. Strategies are presented in the paper.

  17. Evaluation and Verification of Channel Transmission Characteristics of Human Body for Optimizing Data Transmission Rate in Electrostatic-Coupling Intra Body Communication System: A Comparative Analysis.

    Directory of Open Access Journals (Sweden)

    Yuhwai Tseng

    Full Text Available Intra-body communication is a new wireless scheme for transmitting signals through the human body. Understanding the transmission characteristics of the human body is therefore becoming increasingly important. Electrostatic-coupling intra-body communication system in a ground-free situation that integrate electronic products that are discretely located on individuals, such as mobile phones, PDAs, wearable computers, and biomedical sensors, are of particular interest.The human body is modeled as a simplified Resistor-Capacitor network. A virtual ground between the transmitter and receiver in the system is represented by a resister-capacitor network. Value of its resistance and capacitance are determined from a system perspective. The system is characterized by using a mathematical unit step function in digital baseband transmission scheme with and without Manchester code. As a result, the signal-to-noise and to-intersymbol-interference ratios are improved by manipulating the load resistor. The data transmission rate of the system is optimized. A battery-powered transmitter and receiver are developed to validate the proposal.A ground-free system fade signal energy especially for a low-frequency signal limited system transmission rate. The system transmission rate is maximized by simply manipulating the load resistor. Experimental results demonstrate that for a load resistance of 10k-50k Ω, the high-pass 3 dB frequency of the band-pass channel is 400kHz-2MHz in the worst-case scenario. The system allows a Manchester-coded baseband signal to be transmitted at speeds of up to 20M bit per second with signal-to-noise and signal-to-intersymbol-interference ratio of more than 10 dB.The human body can function as a high speed transmission medium with a data transmission rate of 20Mbps in an electrostatic-coupling intra-body communication system. Therefore, a wideband signal can be transmitted directly through the human body with a good signal

  18. Evaluation and Verification of Channel Transmission Characteristics of Human Body for Optimizing Data Transmission Rate in Electrostatic-Coupling Intra Body Communication System: A Comparative Analysis.

    Science.gov (United States)

    Tseng, Yuhwai; Su, Chauchin; Ho, Yingchieh

    2016-01-01

    Intra-body communication is a new wireless scheme for transmitting signals through the human body. Understanding the transmission characteristics of the human body is therefore becoming increasingly important. Electrostatic-coupling intra-body communication system in a ground-free situation that integrate electronic products that are discretely located on individuals, such as mobile phones, PDAs, wearable computers, and biomedical sensors, are of particular interest. The human body is modeled as a simplified Resistor-Capacitor network. A virtual ground between the transmitter and receiver in the system is represented by a resister-capacitor network. Value of its resistance and capacitance are determined from a system perspective. The system is characterized by using a mathematical unit step function in digital baseband transmission scheme with and without Manchester code. As a result, the signal-to-noise and to-intersymbol-interference ratios are improved by manipulating the load resistor. The data transmission rate of the system is optimized. A battery-powered transmitter and receiver are developed to validate the proposal. A ground-free system fade signal energy especially for a low-frequency signal limited system transmission rate. The system transmission rate is maximized by simply manipulating the load resistor. Experimental results demonstrate that for a load resistance of 10k-50k Ω, the high-pass 3 dB frequency of the band-pass channel is 400kHz-2MHz in the worst-case scenario. The system allows a Manchester-coded baseband signal to be transmitted at speeds of up to 20M bit per second with signal-to-noise and signal-to-intersymbol-interference ratio of more than 10 dB. The human body can function as a high speed transmission medium with a data transmission rate of 20Mbps in an electrostatic-coupling intra-body communication system. Therefore, a wideband signal can be transmitted directly through the human body with a good signal-to-noise quality of 10 dB if

  19. Automatic guided wave communication system using steel pipes as communication channel for flood detection in steel offshoreoilrigs; Sistema automatico de comunicacion de ondas guiadas para la deteccion de tubos de refuerzo inundados en plataformas petroleras costa fuera

    Energy Technology Data Exchange (ETDEWEB)

    Mijarez Cstro, Rito; Martinez Ramirez, Fernando [Instituto de Investigaciones Electricas, Cuernavaca, Morelos (Mexico)

    2010-10-09

    An automatic guided wave Pulse Position Modulation (PPM) system, using steel tubes as communication channel, for detecting flooding in the hollow sub-sea structures of offshore oilrigs is presented. The system employs two smart piezoelectric based sensors and modulators and a demodulator based on a piezoelectric transducer, a Digital Signal Processor (DSP) and a microcontroller. Experiments performed in the laboratory, in a tubular steel heliport structure and the base of a deck of an oilrig under construction, have successfully distinguished automatically guided wave encoded information. [Spanish] Este articulo presenta un trabajo de investigacion en el cual se desarrolla un sistema automatico de comunicacion de ondas guiadas por modulacion por posicion de pulsos (PPM), orientado a la deteccion de miembros inundados en los tubos de refuerzo de las plataformas petroleras costa fuera. El sistema utiliza de manera novedosa tubos de acero como medio de comunicacion y emplea dos sensores/moduladores inteligentes compuestos de cristales piezoelectricos, electronica basada en un microcontrolador y baterias. La instrumentacion del demodulador consta de un transductor piezoelectrico de ultrasonido, un procesador digital de senales (DSP) y un microcontrolador, el cual lleva a cabo de manera automatica la deteccion de ondas guiadas. Los experimentos se realizaron en aire, en laboratorio, en una estructura tubular de acero del helipuerto y en la base de una plataforma bajo construccion.

  20. A Call for New Communication Channels for Gynecological Oncology Trainees: A Survey on Social Media Use and Educational Needs by the European Network of Young Gynecological Oncologists.

    Science.gov (United States)

    Zalewski, Kamil; Lindemann, Kristina; Halaska, Michael J; Zapardiel, Ignacio; Laky, Rene; Chereau, Elisabeth; Lindquist, David; Polterauer, Stephan; Sukhin, Vladislav; Dursun, Polat

    2017-03-01

    The aim of the study was to assess patterns in the use of social media (SM) platforms and to identify the training needs among European gynecologic oncology trainees. In 2014, a web-based survey was sent to 633 trainees from the European Network of Young Gynaecological Oncologists (ENYGO) database. The 14-item questionnaire (partially using a 1- to 5-point Likert scale) assessed respondents' use of SM and preference for workshop content and organization. Descriptive analysis was used to describe the mean scores reported for different items, and the internal reliability of the questionnaire was assessed by Cronbach α. In total, 170 ENYGO members (27%) responded to the survey. Of those, 91% said that they use SM platforms, mostly for private purposes. Twenty-three percent used SM professionally and 43% indicated that they would consider SM to be a clinical discussion forum. The respondents said that they would like updates on conferences and professional activities to be shared on SM platforms. Complication management, surgical anatomy, and state of the art in gynecologic oncology were identified as preferred workshops topics. The most frequently indicated hands-on workshops were laparoscopic techniques and surgical anatomy. Consultants attached a higher level of importance to palliative care education and communication training than trainees. The mean duration of the workshop preferred was 2 days. This report highlights the significance of ENYGO trainees' attachment to SM platforms. Most respondents expect ENYGO to use these online channels for promoting educational activities and other updates. Using SM for clinical discussion will require specific guidelines to secure professional and also consumer integrity. This survey confirms surgical management and the state of the art as important knowledge gaps, and ENYGO has tailored its activities according to these results. Future activities will further direct attention and resources to education in palliative care and

  1. Proceedings of the Third International Conference on Intelligent Human Computer Interaction

    CERN Document Server

    Pokorný, Jaroslav; Snášel, Václav; Abraham, Ajith

    2013-01-01

    The Third International Conference on Intelligent Human Computer Interaction 2011 (IHCI 2011) was held at Charles University, Prague, Czech Republic from August 29 - August 31, 2011. This conference was third in the series, following IHCI 2009 and IHCI 2010 held in January at IIIT Allahabad, India. Human computer interaction is a fast growing research area and an attractive subject of interest for both academia and industry. There are many interesting and challenging topics that need to be researched and discussed. This book aims to provide excellent opportunities for the dissemination of interesting new research and discussion about presented topics. It can be useful for researchers working on various aspects of human computer interaction. Topics covered in this book include user interface and interaction, theoretical background and applications of HCI and also data mining and knowledge discovery as a support of HCI applications.

  2. Investigation and evaluation into the usability of human-computer interfaces using a typical CAD system

    Energy Technology Data Exchange (ETDEWEB)

    Rickett, J D

    1987-01-01

    This research program covers three topics relating to the human-computer interface namely, voice recognition, tools and techniques for evaluation, and user and interface modeling. An investigation into the implementation of voice-recognition technologies examines how voice recognizers may be evaluated in commercial software. A prototype system was developed with the collaboration of FEMVIEW Ltd. (marketing a CAD package). A theoretical approach to evaluation leads to the hypothesis that human-computer interaction is affected by personality, influencing types of dialogue, preferred methods for providing helps, etc. A user model based on personality traits, or habitual-behavior patterns (HBP) is presented. Finally, a practical framework is provided for the evaluation of human-computer interfaces. It suggests that evaluation is an integral part of design and that the iterative use of evaluation techniques throughout the conceptualization, design, implementation and post-implementation stages will ensure systems that satisfy the needs of the users and fulfill the goal of usability.

  3. Matching Dyadic Distributions to Channels

    OpenAIRE

    Böcherer, Georg; Mathar, Rudolf

    2010-01-01

    Many communication channels with discrete input have non-uniform capacity achieving probability mass functions (PMF). By parsing a stream of independent and equiprobable bits according to a full prefix-free code, a modu-lator can generate dyadic PMFs at the channel input. In this work, we show that for discrete memoryless channels and for memoryless discrete noiseless channels, searching for good dyadic input PMFs is equivalent to minimizing the Kullback-Leibler distance between a dyadic PMF ...

  4. Glove-Enabled Computer Operations (GECO): Design and Testing of an Extravehicular Activity Glove Adapted for Human-Computer Interface

    Science.gov (United States)

    Adams, Richard J.; Olowin, Aaron; Krepkovich, Eileen; Hannaford, Blake; Lindsay, Jack I. C.; Homer, Peter; Patrie, James T.; Sands, O. Scott

    2013-01-01

    The Glove-Enabled Computer Operations (GECO) system enables an extravehicular activity (EVA) glove to be dual-purposed as a human-computer interface device. This paper describes the design and human participant testing of a right-handed GECO glove in a pressurized glove box. As part of an investigation into the usability of the GECO system for EVA data entry, twenty participants were asked to complete activities including (1) a Simon Says Games in which they attempted to duplicate random sequences of targeted finger strikes and (2) a Text Entry activity in which they used the GECO glove to enter target phrases in two different virtual keyboard modes. In a within-subjects design, both activities were performed both with and without vibrotactile feedback. Participants mean accuracies in correctly generating finger strikes with the pressurized glove were surprisingly high, both with and without the benefit of tactile feedback. Five of the subjects achieved mean accuracies exceeding 99 in both conditions. In Text Entry, tactile feedback provided a statistically significant performance benefit, quantified by characters entered per minute, as well as reduction in error rate. Secondary analyses of responses to a NASA Task Loader Index (TLX) subjective workload assessments reveal a benefit for tactile feedback in GECO glove use for data entry. This first-ever investigation of employment of a pressurized EVA glove for human-computer interface opens up a wide range of future applications, including text chat communications, manipulation of procedureschecklists, cataloguingannotating images, scientific note taking, human-robot interaction, and control of suit andor other EVA systems.

  5. Human-computer interaction handbook fundamentals, evolving technologies and emerging applications

    CERN Document Server

    Sears, Andrew

    2007-01-01

    This second edition of The Human-Computer Interaction Handbook provides an updated, comprehensive overview of the most important research in the field, including insights that are directly applicable throughout the process of developing effective interactive information technologies. It features cutting-edge advances to the scientific knowledge base, as well as visionary perspectives and developments that fundamentally transform the way in which researchers and practitioners view the discipline. As the seminal volume of HCI research and practice, The Human-Computer Interaction Handbook feature

  6. Psychosocial and Cultural Modeling in Human Computation Systems: A Gamification Approach

    Energy Technology Data Exchange (ETDEWEB)

    Sanfilippo, Antonio P.; Riensche, Roderick M.; Haack, Jereme N.; Butner, R. Scott

    2013-11-20

    “Gamification”, the application of gameplay to real-world problems, enables the development of human computation systems that support decision-making through the integration of social and machine intelligence. One of gamification’s major benefits includes the creation of a problem solving environment where the influence of cognitive and cultural biases on human judgment can be curtailed through collaborative and competitive reasoning. By reducing biases on human judgment, gamification allows human computation systems to exploit human creativity relatively unhindered by human error. Operationally, gamification uses simulation to harvest human behavioral data that provide valuable insights for the solution of real-world problems.

  7. Applying systemic-structural activity theory to design of human-computer interaction systems

    CERN Document Server

    Bedny, Gregory Z; Bedny, Inna

    2015-01-01

    Human-Computer Interaction (HCI) is an interdisciplinary field that has gained recognition as an important field in ergonomics. HCI draws on ideas and theoretical concepts from computer science, psychology, industrial design, and other fields. Human-Computer Interaction is no longer limited to trained software users. Today people interact with various devices such as mobile phones, tablets, and laptops. How can you make such interaction user friendly, even when user proficiency levels vary? This book explores methods for assessing the psychological complexity of computer-based tasks. It also p

  8. ATP Release Channels

    Directory of Open Access Journals (Sweden)

    Akiyuki Taruno

    2018-03-01

    Full Text Available Adenosine triphosphate (ATP has been well established as an important extracellular ligand of autocrine signaling, intercellular communication, and neurotransmission with numerous physiological and pathophysiological roles. In addition to the classical exocytosis, non-vesicular mechanisms of cellular ATP release have been demonstrated in many cell types. Although large and negatively charged ATP molecules cannot diffuse across the lipid bilayer of the plasma membrane, conductive ATP release from the cytosol into the extracellular space is possible through ATP-permeable channels. Such channels must possess two minimum qualifications for ATP permeation: anion permeability and a large ion-conducting pore. Currently, five groups of channels are acknowledged as ATP-release channels: connexin hemichannels, pannexin 1, calcium homeostasis modulator 1 (CALHM1, volume-regulated anion channels (VRACs, also known as volume-sensitive outwardly rectifying (VSOR anion channels, and maxi-anion channels (MACs. Recently, major breakthroughs have been made in the field by molecular identification of CALHM1 as the action potential-dependent ATP-release channel in taste bud cells, LRRC8s as components of VRACs, and SLCO2A1 as a core subunit of MACs. Here, the function and physiological roles of these five groups of ATP-release channels are summarized, along with a discussion on the future implications of understanding these channels.

  9. Developing Human-Computer Interface Models and Representation Techniques(Dialogue Management as an Integral Part of Software Engineering)

    OpenAIRE

    Hartson, H. Rex; Hix, Deborah; Kraly, Thomas M.

    1987-01-01

    The Dialogue Management Project at Virginia Tech is studying the poorly understood problem of human-computer dialogue development. This problem often leads to low usability in human-computer dialogues. The Dialogue Management Project approaches solutions to low usability in interfaces by addressing human-computer dialogue development as an integral and equal part of the total system development process. This project consists of two rather distinct, but dependent, parts. One is development of ...

  10. HCI^2 Workbench: A Development Tool for Multimodal Human-Computer Interaction Systems

    NARCIS (Netherlands)

    Shen, Jie; Wenzhe, Shi; Pantic, Maja

    In this paper, we present a novel software tool designed and implemented to simplify the development process of Multimodal Human-Computer Interaction (MHCI) systems. This tool, which is called the HCI^2 Workbench, exploits a Publish / Subscribe (P/S) architecture [13] [14] to facilitate efficient

  11. HCI^2 Framework: A software framework for multimodal human-computer interaction systems

    NARCIS (Netherlands)

    Shen, Jie; Pantic, Maja

    2013-01-01

    This paper presents a novel software framework for the development and research in the area of multimodal human-computer interface (MHCI) systems. The proposed software framework, which is called the HCI∧2 Framework, is built upon publish/subscribe (P/S) architecture. It implements a

  12. The Human-Computer Interaction of Cross-Cultural Gaming Strategy

    Science.gov (United States)

    Chakraborty, Joyram; Norcio, Anthony F.; Van Der Veer, Jacob J.; Andre, Charles F.; Miller, Zachary; Regelsberger, Alexander

    2015-01-01

    This article explores the cultural dimensions of the human-computer interaction that underlies gaming strategies. The article is a desktop study of existing literature and is organized into five sections. The first examines the cultural aspects of knowledge processing. The social constructs technology interaction is discussed. Following this, the…

  13. Enhancing Human-Computer Interaction Design Education: Teaching Affordance Design for Emerging Mobile Devices

    Science.gov (United States)

    Faiola, Anthony; Matei, Sorin Adam

    2010-01-01

    The evolution of human-computer interaction design (HCID) over the last 20 years suggests that there is a growing need for educational scholars to consider new and more applicable theoretical models of interactive product design. The authors suggest that such paradigms would call for an approach that would equip HCID students with a better…

  14. Rational behavior in decision making. A comparison between humans, computers and fast and frugal strategies

    NARCIS (Netherlands)

    Snijders, C.C.P.

    2007-01-01

    Rational behavior in decision making. A comparison between humans, computers, and fast and frugal strategies Chris Snijders and Frits Tazelaar (Eindhoven University of Technology, The Netherlands) Real life decisions often have to be made in "noisy" circumstances: not all crucial information is

  15. Implementations of the CC'01 Human-Computer Interaction Guidelines Using Bloom's Taxonomy

    Science.gov (United States)

    Manaris, Bill; Wainer, Michael; Kirkpatrick, Arthur E.; Stalvey, RoxAnn H.; Shannon, Christine; Leventhal, Laura; Barnes, Julie; Wright, John; Schafer, J. Ben; Sanders, Dean

    2007-01-01

    In today's technology-laden society human-computer interaction (HCI) is an important knowledge area for computer scientists and software engineers. This paper surveys existing approaches to incorporate HCI into computer science (CS) and such related issues as the perceived gap between the interests of the HCI community and the needs of CS…

  16. Human Computation

    CERN Multimedia

    CERN. Geneva

    2008-01-01

    What if people could play computer games and accomplish work without even realizing it? What if billions of people collaborated to solve important problems for humanity or generate training data for computers? My work aims at a general paradigm for doing exactly that: utilizing human processing power to solve computational problems in a distributed manner. In particular, I focus on harnessing human time and energy for addressing problems that computers cannot yet solve. Although computers have advanced dramatically in many respects over the last 50 years, they still do not possess the basic conceptual intelligence or perceptual capabilities...

  17. Human Computer Collaboration at the Edge: Enhancing Collective Situation Understanding with Controlled Natural Language

    Science.gov (United States)

    2016-09-06

    conversational agent with information exchange disabled until the end of the experiment run. The meaning of the indicator in the top- right of the agent... Human Computer Collaboration at the Edge: Enhancing Collective Situation Understanding with Controlled Natural Language Alun Preece∗, William...email: PreeceAD@cardiff.ac.uk †Emerging Technology Services, IBM United Kingdom Ltd, Hursley Park, Winchester, UK ‡US Army Research Laboratory, Human

  18. The Study on Human-Computer Interaction Design Based on the Users’ Subconscious Behavior

    Science.gov (United States)

    Li, Lingyuan

    2017-09-01

    Human-computer interaction is human-centered. An excellent interaction design should focus on the study of user experience, which greatly comes from the consistence between design and human behavioral habit. However, users’ behavioral habits often result from subconsciousness. Therefore, it is smart to utilize users’ subconscious behavior to achieve design's intention and maximize the value of products’ functions, which gradually becomes a new trend in this field.

  19. USING RESEARCH METHODS IN HUMAN COMPUTER INTERACTION TO DESIGN TECHNOLOGY FOR RESILIENCE

    OpenAIRE

    Lopes, Arminda Guerra

    2016-01-01

    ABSTRACT Research in human computer interaction (HCI) covers both technological and human behavioural concerns. As a consequence, the contributions made in HCI research tend to be aware to either engineering or the social sciences. In HCI the purpose of practical research contributions is to reveal unknown insights about human behaviour and its relationship to technology. Practical research methods normally used in HCI include formal experiments, field experiments, field studies, interviews, ...

  20. HCIDL: Human-computer interface description language for multi-target, multimodal, plastic user interfaces

    Directory of Open Access Journals (Sweden)

    Lamia Gaouar

    2018-06-01

    Full Text Available From the human-computer interface perspectives, the challenges to be faced are related to the consideration of new, multiple interactions, and the diversity of devices. The large panel of interactions (touching, shaking, voice dictation, positioning … and the diversification of interaction devices can be seen as a factor of flexibility albeit introducing incidental complexity. Our work is part of the field of user interface description languages. After an analysis of the scientific context of our work, this paper introduces HCIDL, a modelling language staged in a model-driven engineering approach. Among the properties related to human-computer interface, our proposition is intended for modelling multi-target, multimodal, plastic interaction interfaces using user interface description languages. By combining plasticity and multimodality, HCIDL improves usability of user interfaces through adaptive behaviour by providing end-users with an interaction-set adapted to input/output of terminals and, an optimum layout. Keywords: Model driven engineering, Human-computer interface, User interface description languages, Multimodal applications, Plastic user interfaces

  1. Gaze-and-brain-controlled interfaces for human-computer and human-robot interaction

    Directory of Open Access Journals (Sweden)

    Shishkin S. L.

    2017-09-01

    Full Text Available Background. Human-machine interaction technology has greatly evolved during the last decades, but manual and speech modalities remain single output channels with their typical constraints imposed by the motor system’s information transfer limits. Will brain-computer interfaces (BCIs and gaze-based control be able to convey human commands or even intentions to machines in the near future? We provide an overview of basic approaches in this new area of applied cognitive research. Objective. We test the hypothesis that the use of communication paradigms and a combination of eye tracking with unobtrusive forms of registering brain activity can improve human-machine interaction. Methods and Results. Three groups of ongoing experiments at the Kurchatov Institute are reported. First, we discuss the communicative nature of human-robot interaction, and approaches to building a more e cient technology. Specifically, “communicative” patterns of interaction can be based on joint attention paradigms from developmental psychology, including a mutual “eye-to-eye” exchange of looks between human and robot. Further, we provide an example of “eye mouse” superiority over the computer mouse, here in emulating the task of selecting a moving robot from a swarm. Finally, we demonstrate a passive, noninvasive BCI that uses EEG correlates of expectation. This may become an important lter to separate intentional gaze dwells from non-intentional ones. Conclusion. The current noninvasive BCIs are not well suited for human-robot interaction, and their performance, when they are employed by healthy users, is critically dependent on the impact of the gaze on selection of spatial locations. The new approaches discussed show a high potential for creating alternative output pathways for the human brain. When support from passive BCIs becomes mature, the hybrid technology of the eye-brain-computer (EBCI interface will have a chance to enable natural, fluent, and the

  2. IBM 3705 Communications Controller

    CERN Multimedia

    1972-01-01

    The IBM 3705 Communications Controller is a simple computer which attaches to an IBM System/360 or System/370. Its purpose is to connect communication lines to the mainframe channel. It was a first communications controller of the popular IBM 37xx series.

  3. Channel Identification Machines

    Directory of Open Access Journals (Sweden)

    Aurel A. Lazar

    2012-01-01

    Full Text Available We present a formal methodology for identifying a channel in a system consisting of a communication channel in cascade with an asynchronous sampler. The channel is modeled as a multidimensional filter, while models of asynchronous samplers are taken from neuroscience and communications and include integrate-and-fire neurons, asynchronous sigma/delta modulators and general oscillators in cascade with zero-crossing detectors. We devise channel identification algorithms that recover a projection of the filter(s onto a space of input signals loss-free for both scalar and vector-valued test signals. The test signals are modeled as elements of a reproducing kernel Hilbert space (RKHS with a Dirichlet kernel. Under appropriate limiting conditions on the bandwidth and the order of the test signal space, the filter projection converges to the impulse response of the filter. We show that our results hold for a wide class of RKHSs, including the space of finite-energy bandlimited signals. We also extend our channel identification results to noisy circuits.

  4. Channel identification machines.

    Science.gov (United States)

    Lazar, Aurel A; Slutskiy, Yevgeniy B

    2012-01-01

    We present a formal methodology for identifying a channel in a system consisting of a communication channel in cascade with an asynchronous sampler. The channel is modeled as a multidimensional filter, while models of asynchronous samplers are taken from neuroscience and communications and include integrate-and-fire neurons, asynchronous sigma/delta modulators and general oscillators in cascade with zero-crossing detectors. We devise channel identification algorithms that recover a projection of the filter(s) onto a space of input signals loss-free for both scalar and vector-valued test signals. The test signals are modeled as elements of a reproducing kernel Hilbert space (RKHS) with a Dirichlet kernel. Under appropriate limiting conditions on the bandwidth and the order of the test signal space, the filter projection converges to the impulse response of the filter. We show that our results hold for a wide class of RKHSs, including the space of finite-energy bandlimited signals. We also extend our channel identification results to noisy circuits.

  5. Engageability: a new sub-principle of the learnability principle in human-computer interaction

    Directory of Open Access Journals (Sweden)

    B Chimbo

    2011-12-01

    Full Text Available The learnability principle relates to improving the usability of software, as well as users’ performance and productivity. A gap has been identified as the current definition of the principle does not distinguish between users of different ages. To determine the extent of the gap, this article compares the ways in which two user groups, adults and children, learn how to use an unfamiliar software application. In doing this, we bring together the research areas of human-computer interaction (HCI, adult and child learning, learning theories and strategies, usability evaluation and interaction design. A literature survey conducted on learnability and learning processes considered the meaning of learnability of software applications across generations. In an empirical investigation, users aged from 9 to 12 and from 35 to 50 were observed in a usability laboratory while learning to use educational software applications. Insights that emerged from data analysis showed different tactics and approaches that children and adults use when learning unfamiliar software. Eye tracking data was also recorded. Findings indicated that subtle re- interpretation of the learnability principle and its associated sub-principles was required. An additional sub-principle, namely engageability was proposed to incorporate aspects of learnability that are not covered by the existing sub-principles. Our re-interpretation of the learnability principle and the resulting design recommendations should help designers to fulfill the varying needs of different-aged users, and improve the learnability of their designs. Keywords: Child computer interaction, Design principles, Eye tracking, Generational differences, human-computer interaction, Learning theories, Learnability, Engageability, Software applications, Uasability Disciplines: Human-Computer Interaction (HCI Studies, Computer science, Observational Studies

  6. Real-time non-invasive eyetracking and gaze-point determination for human-computer interaction and biomedicine

    Science.gov (United States)

    Talukder, Ashit; Morookian, John-Michael; Monacos, S.; Lam, R.; Lebaw, C.; Bond, A.

    2004-01-01

    Eyetracking is one of the latest technologies that has shown potential in several areas including human-computer interaction for people with and without disabilities, and for noninvasive monitoring, detection, and even diagnosis of physiological and neurological problems in individuals.

  7. Square root approximation to the poisson channel

    NARCIS (Netherlands)

    Tsiatmas, A.; Willems, F.M.J.; Baggen, C.P.M.J.

    2013-01-01

    Starting from the Poisson model we present a channel model for optical communications, called the Square Root (SR) Channel, in which the noise is additive Gaussian with constant variance. Initially, we prove that for large peak or average power, the transmission rate of a Poisson Channel when coding

  8. Human-Computer Interaction Handbook Fundamentals, Evolving Technologies, and Emerging Applications

    CERN Document Server

    Jacko, Julie A

    2012-01-01

    The third edition of a groundbreaking reference, The Human--Computer Interaction Handbook: Fundamentals, Evolving Technologies, and Emerging Applications raises the bar for handbooks in this field. It is the largest, most complete compilation of HCI theories, principles, advances, case studies, and more that exist within a single volume. The book captures the current and emerging sub-disciplines within HCI related to research, development, and practice that continue to advance at an astonishing rate. It features cutting-edge advances to the scientific knowledge base as well as visionary perspe

  9. Human-computer interfaces applied to numerical solution of the Plateau problem

    Science.gov (United States)

    Elias Fabris, Antonio; Soares Bandeira, Ivana; Ramos Batista, Valério

    2015-09-01

    In this work we present a code in Matlab to solve the Problem of Plateau numerically, and the code will include human-computer interface. The Problem of Plateau has applications in areas of knowledge like, for instance, Computer Graphics. The solution method will be the same one of the Surface Evolver, but the difference will be a complete graphical interface with the user. This will enable us to implement other kinds of interface like ocular mouse, voice, touch, etc. To date, Evolver does not include any graphical interface, which restricts its use by the scientific community. Specially, its use is practically impossible for most of the Physically Challenged People.

  10. Non-verbal communication through sensor fusion

    Science.gov (United States)

    Tairych, Andreas; Xu, Daniel; O'Brien, Benjamin M.; Anderson, Iain A.

    2016-04-01

    When we communicate face to face, we subconsciously engage our whole body to convey our message. In telecommunication, e.g. during phone calls, this powerful information channel cannot be used. Capturing nonverbal information from body motion and transmitting it to the receiver parallel to speech would make these conversations feel much more natural. This requires a sensing device that is capable of capturing different types of movements, such as the flexion and extension of joints, and the rotation of limbs. In a first embodiment, we developed a sensing glove that is used to control a computer game. Capacitive dielectric elastomer (DE) sensors measure finger positions, and an inertial measurement unit (IMU) detects hand roll. These two sensor technologies complement each other, with the IMU allowing the player to move an avatar through a three-dimensional maze, and the DE sensors detecting finger flexion to fire weapons or open doors. After demonstrating the potential of sensor fusion in human-computer interaction, we take this concept to the next level and apply it in nonverbal communication between humans. The current fingerspelling glove prototype uses capacitive DE sensors to detect finger gestures performed by the sending person. These gestures are mapped to corresponding messages and transmitted wirelessly to another person. A concept for integrating an IMU into this system is presented. The fusion of the DE sensor and the IMU combines the strengths of both sensor types, and therefore enables very comprehensive body motion sensing, which makes a large repertoire of gestures available to nonverbal communication over distances.

  11. A Model-based Framework for Risk Assessment in Human-Computer Controlled Systems

    Science.gov (United States)

    Hatanaka, Iwao

    2000-01-01

    The rapid growth of computer technology and innovation has played a significant role in the rise of computer automation of human tasks in modem production systems across all industries. Although the rationale for automation has been to eliminate "human error" or to relieve humans from manual repetitive tasks, various computer-related hazards and accidents have emerged as a direct result of increased system complexity attributed to computer automation. The risk assessment techniques utilized for electromechanical systems are not suitable for today's software-intensive systems or complex human-computer controlled systems. This thesis will propose a new systemic model-based framework for analyzing risk in safety-critical systems where both computers and humans are controlling safety-critical functions. A new systems accident model will be developed based upon modem systems theory and human cognitive processes to better characterize system accidents, the role of human operators, and the influence of software in its direct control of significant system functions. Better risk assessments will then be achievable through the application of this new framework to complex human-computer controlled systems.

  12. Effects of muscle fatigue on the usability of a myoelectric human-computer interface.

    Science.gov (United States)

    Barszap, Alexander G; Skavhaug, Ida-Maria; Joshi, Sanjay S

    2016-10-01

    Electromyography-based human-computer interface development is an active field of research. However, knowledge on the effects of muscle fatigue for specific devices is limited. We have developed a novel myoelectric human-computer interface in which subjects continuously navigate a cursor to targets by manipulating a single surface electromyography (sEMG) signal. Two-dimensional control is achieved through simultaneous adjustments of power in two frequency bands through a series of dynamic low-level muscle contractions. Here, we investigate the potential effects of muscle fatigue during the use of our interface. In the first session, eight subjects completed 300 cursor-to-target trials without breaks; four using a wrist muscle and four using a head muscle. The wrist subjects returned for a second session in which a static fatiguing exercise took place at regular intervals in-between cursor-to-target trials. In the first session we observed no declines in performance as a function of use, even after the long period of use. In the second session, we observed clear changes in cursor trajectories, paired with a target-specific decrease in hit rates. Copyright © 2016 Elsevier B.V. All rights reserved.

  13. COMMUNICATION - ORGANIZATIONS’ WORK DEVICE

    OpenAIRE

    LAVINIA HULEA

    2010-01-01

    Communication represents a complex process of transmitting messages, owing to which the emitter encodes the information transmitted through a specific channel towards a receiver that will decode it. Owing to communication, organizations transmit to their customers the fact that they are capable of meeting one of their needs, of settling a problem or of offering a profit. Non-verbal and para-verbal communications usually accompany verbal communication. The importance of assimilating the forms ...

  14. Quantum communication, reference frames, and gauge theory

    International Nuclear Information System (INIS)

    Enk, S. J. van

    2006-01-01

    We consider quantum communication in the case that the communicating parties not only do not share a reference frame but use imperfect quantum communication channels, in that each channel applies some fixed but unknown unitary rotation to each qubit. We discuss similarities and differences between reference frames within that quantum communication model and gauge fields in gauge theory. We generalize the concept of refbits and analyze various quantum communication protocols within the communication model

  15. Ion channeling

    International Nuclear Information System (INIS)

    Erramli, H.; Blondiaux, G.

    1994-01-01

    Channeling phenomenon was predicted, many years ago, by stark. The first channeling experiments were performed in 1963 by Davies and his coworkers. Parallely Robinson and Oen have investigated this process by simulating trajectories of ions in monocrystals. This technique has been combined with many methods like Rutherford Backscattering Spectrometry (R.B.S.), Particles Induced X-rays Emission (P.I.X.E) and online Nuclear Reaction (N.R.A.) to localize trace elements in the crystal or to determine crystalline quality. To use channeling for material characterization we need data about the stopping power of the incident particle in the channeled direction. The ratios of channeled to random stopping powers of silicon for irradiation in the direction have been investigated and compared to the available theoretical results. We describe few applications of ion channeling in the field of materials characterization. Special attention is given to ion channeling combined with Charged Particle Activation Analysis (C.P.A.A.) for studying the behaviour of oxygen atoms in Czochralski silicon lattices under the influence of internal gettering and in different gaseous atmospheres. Association between ion channeling and C.P.A.A was also utilised for studying the influence of the growing conditions on concentration and position of carbon atoms at trace levels in the MOVPE Ga sub (1-x) Al sub x lattice. 6 figs., 1 tab., 32 refs. (author)

  16. Radio propagation measurement and channel modelling

    CERN Document Server

    Salous, Sana

    2013-01-01

    While there are numerous books describing modern wireless communication systems that contain overviews of radio propagation and radio channel modelling, there are none that contain detailed information on the design, implementation and calibration of radio channel measurement equipment, the planning of experiments and the in depth analysis of measured data. The book would begin with an explanation of the fundamentals of radio wave propagation and progress through a series of topics, including the measurement of radio channel characteristics, radio channel sounders, measurement strategies

  17. Credentialed Secure Communication "Switchboards"

    National Research Council Canada - National Science Library

    Freudenthal, Eric; Port, Lawrence; Keenan, Edward; Pesin, Tracy; Karamcheti, Vijay

    2001-01-01

    ... with connection monitoring facilities. Switchboard extends the secure authenticated communication channel abstraction provided by standard interfaces such as SSL/TLS with mechanisms to support trust management, key sharing, service...

  18. Digital Communication and Modulation

    DEFF Research Database (Denmark)

    Sørensen, John Aasted

    2010-01-01

    Fundamental principles in modern digital communication system like modems and wire- and wireless transmission over physical channels. Class room sessions and projects. Semester: Spring 2010 Extent: 7.5 ects Class size: 9......Fundamental principles in modern digital communication system like modems and wire- and wireless transmission over physical channels. Class room sessions and projects. Semester: Spring 2010 Extent: 7.5 ects Class size: 9...

  19. Digital Communication and Modulation

    DEFF Research Database (Denmark)

    Sørensen, John Aasted

    2010-01-01

    Fundamental principles in modern digital communication system like modems and wire- and wireless transmission over physical channels. Class room sessions and projects. Semester: Autumn 2010 Extent: 7.5 ects Class size: 18......Fundamental principles in modern digital communication system like modems and wire- and wireless transmission over physical channels. Class room sessions and projects. Semester: Autumn 2010 Extent: 7.5 ects Class size: 18...

  20. Channel box

    International Nuclear Information System (INIS)

    Tanabe, Akira.

    1993-01-01

    In a channel box of a BWR type reactor, protruding pads are disposed in axial position on the lateral side of a channel box opposing to a control rod and facing the outer side portion of the control rod in a reactor core loaded state. In the initial loading stage of fuel assemblies, channel fasteners and spacer pads are abutted against each other in the upper portion between the channel boxes sandwiching the control rod therebetween. Further, in the lower portion, a gap as a channel for the movement of the control rod is ensured by the support of fuel support metals. If the channel box is bent toward the control rod along with reactor operation, the pads are abutted against each other to always ensure the gap through which the control rod can move easily. Further, when the pads are brought into contact with each other, the bending deformation of the channel box is corrected by urging to each other. Thus, the control rod can always be moved smoothly to attain reactor safety operation. (N.H.)

  1. Human-computer interaction for alert warning and attention allocation systems of the multimodal watchstation

    Science.gov (United States)

    Obermayer, Richard W.; Nugent, William A.

    2000-11-01

    The SPAWAR Systems Center San Diego is currently developing an advanced Multi-Modal Watchstation (MMWS); design concepts and software from this effort are intended for transition to future United States Navy surface combatants. The MMWS features multiple flat panel displays and several modes of user interaction, including voice input and output, natural language recognition, 3D audio, stylus and gestural inputs. In 1999, an extensive literature review was conducted on basic and applied research concerned with alerting and warning systems. After summarizing that literature, a human computer interaction (HCI) designer's guide was prepared to support the design of an attention allocation subsystem (AAS) for the MMWS. The resultant HCI guidelines are being applied in the design of a fully interactive AAS prototype. An overview of key findings from the literature review, a proposed design methodology with illustrative examples, and an assessment of progress made in implementing the HCI designers guide are presented.

  2. Treatment of human-computer interface in a decision support system

    International Nuclear Information System (INIS)

    Heger, A.S.; Duran, F.A.; Cox, R.G.

    1992-01-01

    One of the most challenging applications facing the computer community is development of effective adaptive human-computer interface. This challenge stems from the complex nature of the human part of this symbiosis. The application of this discipline to the environmental restoration and waste management is further complicated due to the nature of environmental data. The information that is required to manage environmental impacts of human activity is fundamentally complex. This paper will discuss the efforts at Sandia National Laboratories in developing the adaptive conceptual model manager within the constraint of the environmental decision-making. A computer workstation, that hosts the Conceptual Model Manager and the Sandia Environmental Decision Support System will also be discussed

  3. Soft Electronics Enabled Ergonomic Human-Computer Interaction for Swallowing Training

    Science.gov (United States)

    Lee, Yongkuk; Nicholls, Benjamin; Sup Lee, Dong; Chen, Yanfei; Chun, Youngjae; Siang Ang, Chee; Yeo, Woon-Hong

    2017-04-01

    We introduce a skin-friendly electronic system that enables human-computer interaction (HCI) for swallowing training in dysphagia rehabilitation. For an ergonomic HCI, we utilize a soft, highly compliant (“skin-like”) electrode, which addresses critical issues of an existing rigid and planar electrode combined with a problematic conductive electrolyte and adhesive pad. The skin-like electrode offers a highly conformal, user-comfortable interaction with the skin for long-term wearable, high-fidelity recording of swallowing electromyograms on the chin. Mechanics modeling and experimental quantification captures the ultra-elastic mechanical characteristics of an open mesh microstructured sensor, conjugated with an elastomeric membrane. Systematic in vivo studies investigate the functionality of the soft electronics for HCI-enabled swallowing training, which includes the application of a biofeedback system to detect swallowing behavior. The collection of results demonstrates clinical feasibility of the ergonomic electronics in HCI-driven rehabilitation for patients with swallowing disorders.

  4. Twenty Years of Creativity Research in Human-Computer Interaction: Current State and Future Directions

    DEFF Research Database (Denmark)

    Frich Pedersen, Jonas; Biskjaer, Michael Mose; Dalsgaard, Peter

    2018-01-01

    Creativity has been a growing topic within the ACM community since the 1990s. However, no clear overview of this trend has been offered. We present a thorough survey of 998 creativity-related publications in the ACM Digital Library collected using keyword search to determine prevailing approaches......, topics, and characteristics of creativity-oriented Human-Computer Interaction (HCI) research. . A selected sample based on yearly citations yielded 221 publications, which were analyzed using constant comparison analysis. We found that HCI is almost exclusively responsible for creativity......-oriented publications; they focus on collaborative creativity rather than individual creativity; there is a general lack of definition of the term ‘creativity’; empirically based contributions are prevalent; and many publications focus on new tools, often developed by researchers. On this basis, we present three...

  5. Cognitive engineering models: A prerequisite to the design of human-computer interaction in complex dynamic systems

    Science.gov (United States)

    Mitchell, Christine M.

    1993-01-01

    This chapter examines a class of human-computer interaction applications, specifically the design of human-computer interaction for the operators of complex systems. Such systems include space systems (e.g., manned systems such as the Shuttle or space station, and unmanned systems such as NASA scientific satellites), aviation systems (e.g., the flight deck of 'glass cockpit' airplanes or air traffic control) and industrial systems (e.g., power plants, telephone networks, and sophisticated, e.g., 'lights out,' manufacturing facilities). The main body of human-computer interaction (HCI) research complements but does not directly address the primary issues involved in human-computer interaction design for operators of complex systems. Interfaces to complex systems are somewhat special. The 'user' in such systems - i.e., the human operator responsible for safe and effective system operation - is highly skilled, someone who in human-machine systems engineering is sometimes characterized as 'well trained, well motivated'. The 'job' or task context is paramount and, thus, human-computer interaction is subordinate to human job interaction. The design of human interaction with complex systems, i.e., the design of human job interaction, is sometimes called cognitive engineering.

  6. Restricciones en el canal de comunicación y representación de influencia en situación de toma de decisión Restrictions in the communication channel and influence representation in taking up decisions

    Directory of Open Access Journals (Sweden)

    Jorge R. Vivas

    2001-06-01

    Full Text Available La comunicación mediada por computadora ha tenido un efecto de alto impacto social en la última década. Los efectos psicosociales de la utilización de estos medios tecnológicos en la comunicación humana son observados con creciente interés. Este trabajo reporta las variaciones de la percepción de influencia durante una tarea de toma de decisión colaborativa al modificar las restricciones del canal de comunicación (presencial o mediado por computadora. Se trabajó con cien sujetos repartidos en ambas condiciones de tarea sobre un problema de decisión múltiple. Los análisis muestran una diferencia notable en los aspectos considerados por los individuos para la construcción de la representación de influencia en una y otra modalidad. Estas diferencias son interpretadas como producto de que la magnitud de la presencia social esta modulada por las restricciones inherentes al canal mediador, dificultando y hasta impidiendo, la percepción de los mecanismos de influencia social que permiten la construcción de una representación de influencia ajustada a los efectivos intercambios realizados en torno al producto generado colaborativamente.Computer mediated communication had a high social impact in the last decade. The psychosocial effects of the use of these technological media on human communication are observed with growing interest. This work reports the differences of influence perception during the collaborative making decision task when varying the communicational channel restrictions (Face To Face or computer mediated. The design included a hundred students in both task conditions on a multiple decision problem. The outcomes show a great differences in how individuals remarks different aspects for the representational construction of the influence in each modality. These results suggest that the amount of social presence is modulated by the channel restrictions, which make it difficult and even constrain, the perception of the

  7. Surface channeling

    International Nuclear Information System (INIS)

    Sizmann, R.; Varelas, C.

    1976-01-01

    There is experimental evidence that swift light ions incident at small angles towards single crystalline surfaces can lose an appreciable fraction of their kinetic energy during reflection. It is shown that these projectiles penetrate into the bulk surface region of the crystal. They can travel as channeled particles along long paths through the solid (surface channeling). The angular distribution and the depth history of the re-emerged projectiles are investigated by computer simulations. A considerable fraction of the penetrating projectiles re-emerges from the crystal with constant transverse energy if the angle of incidence is smaller than the critical angle for axial channeling. Analytical formulae are derived based on a diffusion model for surface channeling. A comparison with experimental data exhibits the relevance of the analytical solutions. (Auth.)

  8. Channel perceptions and usage: beyond media richness factors

    NARCIS (Netherlands)

    Pieterson, Willem Jan; Teerling, Marije; Ebbers, Wolfgang E.; Wimmer, Maria A.; Scholl, Hans J.; Ferro, Enrico

    2008-01-01

    In this paper, we asses how service channel perceptions affect channel choice and channel usage. Building on communication theories, such as the Media Richness Theory, we explore how different channel characteristics are perceived by citizens in a Dutch governmental service chain. The results of our

  9. On the performance of dual-hop mixed RF/FSO wireless communication system in urban area over aggregated exponentiated Weibull fading channels with pointing errors

    Science.gov (United States)

    Wang, Yue; Wang, Ping; Liu, Xiaoxia; Cao, Tian

    2018-03-01

    The performance of decode-and-forward dual-hop mixed radio frequency / free-space optical system in urban area is studied. The RF link is modeled by the Nakagami-m distribution and the FSO link is described by the composite exponentiated Weibull (EW) fading channels with nonzero boresight pointing errors (NBPE). For comparison, the ABER results without pointing errors (PE) and those with zero boresight pointing errors (ZBPE) are also provided. The closed-form expression for the average bit error rate (ABER) in RF link is derived with the help of hypergeometric function, and that in FSO link is obtained by Meijer's G and generalized Gauss-Laguerre quadrature functions. Then, the end-to-end ABERs with binary phase shift keying modulation are achieved on the basis of the computed ABER results of RF and FSO links. The end-to-end ABER performance is further analyzed with different Nakagami-m parameters, turbulence strengths, receiver aperture sizes and boresight displacements. The result shows that with ZBPE and NBPE considered, FSO link suffers a severe ABER degradation and becomes the dominant limitation of the mixed RF/FSO system in urban area. However, aperture averaging can bring significant ABER improvement of this system. Monte Carlo simulation is provided to confirm the validity of the analytical ABER expressions.

  10. Spark Channels

    Energy Technology Data Exchange (ETDEWEB)

    Haydon, S. C. [Department of Physics, University of New England, Armidale, NSW (Australia)

    1968-04-15

    A brief summary is given of the principal methods used for initiating spark channels and the various highly time-resolved techniques developed recently for studies with nanosecond resolution. The importance of the percentage overvoltage in determining the early history and subsequent development of the various phases of the growth of the spark channel is discussed. An account is then given of the recent photographic, oscillographic and spectroscopic investigations of spark channels initiated by co-axial cable discharges of spark gaps at low [{approx} 1%] overvoltages. The phenomena observed in the development of the immediate post-breakdown phase, the diffuse glow structure, the growth of the luminous filament and the final formation of the spark channel in hydrogen are described. A brief account is also given of the salient features emerging from corresponding studies of highly overvolted spark gaps in which the spark channel develops from single avalanche conditions. The essential differences between the two types of channel formation are summarized and possible explanations of the general features are indicated. (author)

  11. Design of Transport Layer Based Hybrid Covert Channel Detection Engine

    OpenAIRE

    K, Anjan; Abraham, Jibi; Jadhav V, Mamatha

    2010-01-01

    Computer network is unpredictable due to information warfare and is prone to various attacks. Such attacks on network compromise the most important attribute, the privacy. Most of such attacks are devised using special communication channel called "Covert Channel". The word "Covert" stands for hidden or non-transparent. Network Covert Channel is a concealed communication path within legitimate network communication that clearly violates security policies laid down. The non-transparency in cov...

  12. Regenerative Payload for GSAT-3 & Advanced Communication ...

    Indian Academy of Sciences (India)

    First page Back Continue Last page Overview Graphics. Regenerative Payload for GSAT-3 & Advanced Communication Series Satellite. GSAT-4. 8 Ka -Band Spot Beams; 8 Narrow Band (64Kbps) Channels/ Beam; 1 Wide Band (2Mbps) Channel/ Beam;; 64 Kbps Signaling Channel; On-Board Switch Matrix; 8 Channel ...

  13. MARKETING CHANNELS

    Directory of Open Access Journals (Sweden)

    Ljiljana Stošić Mihajlović

    2014-07-01

    Full Text Available Marketing channel is a set of entities and institutions, completion of distribution and marketing activities, attend the efficient and effective networking of producers and consumers. Marketing channels include the total flows of goods, money and information taking place between the institutions in the system of marketing, establishing a connection between them. The functions of the exchange, the physical supply and service activities, inherent in the system of marketing and trade. They represent paths which products and services are moving after the production, which will ultimately end up buying and eating by the user.

  14. A Perspective on the MIMO Wiretap Channel

    KAUST Repository

    Oggier, Frederique; Hassibi, Babak

    2015-01-01

    A wiretap channel is a communication channel between a transmitter Alice and a legitimate receiver Bob, in the presence of an eavesdropper Eve. The goal of communication is to achieve reliability between Alice and Bob, but also confidentiality despite Eve’s presence. Wiretap channels are declined in all kinds of flavors, depending on the underlying channels used by the three players: discrete memoryless channels, additive Gaussian noise channels, or fading channels, to name a few. In this survey, we focus on the case where the three players use multiple-antenna channels with Gaussian noise to communicate. After summarizing known results for multiple-input–multiple-output (MIMO) channels, both in terms of achievable reliable data rate (capacity) and code design, we introduce the MIMO wiretap channel. We then state the MIMO wiretap capacity, summarize the idea of the proof(s) behind this result, and comment on the insights given by the proofs on the physical meaning of the secrecy capacity. We finally discuss design criteria for MIMO wiretap codes.

  15. A Perspective on the MIMO Wiretap Channel

    KAUST Repository

    Oggier, Frederique

    2015-10-01

    A wiretap channel is a communication channel between a transmitter Alice and a legitimate receiver Bob, in the presence of an eavesdropper Eve. The goal of communication is to achieve reliability between Alice and Bob, but also confidentiality despite Eve’s presence. Wiretap channels are declined in all kinds of flavors, depending on the underlying channels used by the three players: discrete memoryless channels, additive Gaussian noise channels, or fading channels, to name a few. In this survey, we focus on the case where the three players use multiple-antenna channels with Gaussian noise to communicate. After summarizing known results for multiple-input–multiple-output (MIMO) channels, both in terms of achievable reliable data rate (capacity) and code design, we introduce the MIMO wiretap channel. We then state the MIMO wiretap capacity, summarize the idea of the proof(s) behind this result, and comment on the insights given by the proofs on the physical meaning of the secrecy capacity. We finally discuss design criteria for MIMO wiretap codes.

  16. Variable Step Closed Loop Power Control with Space Diversity for Low Elevation Angle High Altitude Platforms Communication Channel [Langkah Variabel Kontrol Daya Loop Tertutup dengan Keragaman Ruang untuk Sudut Elevasi Rendah pada Kanal Komunikasi HAPs

    Directory of Open Access Journals (Sweden)

    Iskandar Iskandar

    2016-07-01

    Full Text Available This paper proposes variable step closed loop power control algorithm combined with space diversity to improve the performance of High Altitude Platforms (HAPs communication at low elevation angle using Code Division Multiple Access (CDMA. In this contribution, we first develop HAPs channel model which is derived from experimental measurement. From our experiment, we found HAPs channel characteristic can be modeled as a Ricean distribution because the presence of line of sight path. Different elevation angle resulting different K factor value.  This value is then used in Signal to Interference Ratio (SIR based closed loop power control evaluation. The variable step algorithm is simulated under various elevation angles with different speed of mobile user. The performance is presented in terms of user elevation angle, user speed, step size and space diversity order. We found that the performance of variable step closed-loop power control less effective at low elevation angle. However our simulation shows that space diversity is able to improve the performance of closed loop power control for HAPs channel at low elevation angle.*****Kajian ini mengusulkan suatu algoritma kontrol daya langkah variabel loop tertutup dikombinasikan dengan keragaman ruang untuk meningkatkan kinerja komunikasi High Altitude Platforms(HAPs pada sudut elevasi rendah menggunakan Code Division Multiple Access (CDMA. Kami berkontribusi untuk mengembangkan model kanal HAPs yang berasal dari pengukuran eksperimental sebelumnya. Dari percobaan tersebut, kami menemukan karakteristik kanal HAPs yang dapat dimodelkan sebagai distribusi Ricean karena kehadiran jalur tanpa penghalang. Eksperimen menunjukkan bahwa perbedaan sudut elevasi menghasilkan perbedaan nilai factor K. Nilai ini kemudian digunakan dalam Signal to Interference Ratio (SIR berbasiskan evaluasi kontrol daya loop tertutup. Algoritma langkah variabel disimulasikan dibawah sudut elevasi yang berbeda dengan kecepatan

  17. Analysis of synchronous digital-modulation schemes for satellite communication

    Science.gov (United States)

    Takhar, G. S.; Gupta, S. C.

    1975-01-01

    The multipath communication channel for space communications is modeled as a multiplicative channel. This paper discusses the effects of multiplicative channel processes on the symbol error rate for quadrature modulation (QM) digital modulation schemes. An expression for the upper bound on the probability of error is derived and numerically evaluated. The results are compared with those obtained for additive channels.

  18. Using the Communication Methods, Tools and Support During Management of Project Communication in Industrial Manufacturing Enterprises

    Science.gov (United States)

    Samáková, Jana; Babčanová, Dagmar; Hrablikchovanová, Henrieta; Mesárošová, Jana; Šujanová, Jana

    2017-09-01

    Effective communication is the most significant ability for project manager and successful project. However, during the management of projects communication, it is very often forgotten, often overlooked or taken for granted. In the management of projects, it is principally necessary to deal with communication during all project lifecycle. Within the project communication, it is very important to define the main methods, tools, support of communication and frequency of communication; these belong to the most important elements of the communication channel which is very often forgotten. Therefore, the main aim of the paper is to analyse the utilisation of the communication channel: communication methods, communication tools, communication frequency and to support project communication in industrial manufacturing enterprises in Slovakia. Based on the research, we can conclude that communication channel is not adequately elaborated in international methodologies and standards of project management as well as in industrial manufacturing enterprises. These facts are very negative, conclusion and it is therefore necessary to deal with the problem.

  19. User involvement in the design of human-computer interactions: some similarities and differences between design approaches

    NARCIS (Netherlands)

    Bekker, M.M.; Long, J.B.

    1998-01-01

    This paper presents a general review of user involvement in the design of human-computer interactions, as advocated by a selection of different approaches to design. The selection comprises User-Centred Design, Participatory Design, Socio-Technical Design, Soft Systems Methodology, and Joint

  20. Human-Computer Interaction and Sociological Insight: A Theoretical Examination and Experiment in Building Affinity in Small Groups

    Science.gov (United States)

    Oren, Michael Anthony

    2011-01-01

    The juxtaposition of classic sociological theory and the, relatively, young discipline of human-computer interaction (HCI) serves as a powerful mechanism for both exploring the theoretical impacts of technology on human interactions as well as the application of technological systems to moderate interactions. It is the intent of this dissertation…

  1. The mind-writing pupil : A human-computer interface based on decoding of covert attention through pupillometry

    NARCIS (Netherlands)

    Mathôt, Sebastiaan; Melmi, Jean Baptiste; Van Der Linden, Lotje; Van Der Stigchel, Stefan

    2016-01-01

    We present a new human-computer interface that is based on decoding of attention through pupillometry. Our method builds on the recent finding that covert visual attention affects the pupillary light response: Your pupil constricts when you covertly (without looking at it) attend to a bright,

  2. VAX CAMAC channel

    International Nuclear Information System (INIS)

    Nelson, D.J.; Breidenbach, M.; Granieri, C.D.; Grund, J.E.; Patrick, J.F.; Weaver, L.J.

    1980-10-01

    A new generation CAMAC System has been developed for the Mark II Detector at SLAC's PEP storage ring. This flexible system can efficiently transfer data between a host computer and a very large set of CAMAC data acquisition and control modules. A bipolar microprocessor operates as a Channel interface by supervising the CAMAC system and minimizing the host computer's work. This programmable channel couples the host to a set of System Crates; each System Crate houses Branch Drivers that can directly control a set of crates or communicate over differential parallel highways to Branch Receivers for control of distant crates. A coherent software package integrates the high level programs, system driver level programs, and microcode control of the system

  3. Spectrum Scarcity and Free Space Optical Communications

    KAUST Repository

    Alouini, Mohamed-Slim

    2014-01-01

    Exact and asymptotic studies of the average error probability of wireless communication systems over generalized fading channels have been extensively pursued over the last two decades. In contrast, studies and results dealing with the channel

  4. Integrated multimodal human-computer interface and augmented reality for interactive display applications

    Science.gov (United States)

    Vassiliou, Marius S.; Sundareswaran, Venkataraman; Chen, S.; Behringer, Reinhold; Tam, Clement K.; Chan, M.; Bangayan, Phil T.; McGee, Joshua H.

    2000-08-01

    We describe new systems for improved integrated multimodal human-computer interaction and augmented reality for a diverse array of applications, including future advanced cockpits, tactical operations centers, and others. We have developed an integrated display system featuring: speech recognition of multiple concurrent users equipped with both standard air- coupled microphones and novel throat-coupled sensors (developed at Army Research Labs for increased noise immunity); lip reading for improving speech recognition accuracy in noisy environments, three-dimensional spatialized audio for improved display of warnings, alerts, and other information; wireless, coordinated handheld-PC control of a large display; real-time display of data and inferences from wireless integrated networked sensors with on-board signal processing and discrimination; gesture control with disambiguated point-and-speak capability; head- and eye- tracking coupled with speech recognition for 'look-and-speak' interaction; and integrated tetherless augmented reality on a wearable computer. The various interaction modalities (speech recognition, 3D audio, eyetracking, etc.) are implemented a 'modality servers' in an Internet-based client-server architecture. Each modality server encapsulates and exposes commercial and research software packages, presenting a socket network interface that is abstracted to a high-level interface, minimizing both vendor dependencies and required changes on the client side as the server's technology improves.

  5. Design of a compact low-power human-computer interaction equipment for hand motion

    Science.gov (United States)

    Wu, Xianwei; Jin, Wenguang

    2017-01-01

    Human-Computer Interaction (HCI) raises demand of convenience, endurance, responsiveness and naturalness. This paper describes a design of a compact wearable low-power HCI equipment applied to gesture recognition. System combines multi-mode sense signals: the vision sense signal and the motion sense signal, and the equipment is equipped with the depth camera and the motion sensor. The dimension (40 mm × 30 mm) and structure is compact and portable after tight integration. System is built on a module layered framework, which contributes to real-time collection (60 fps), process and transmission via synchronous confusion with asynchronous concurrent collection and wireless Blue 4.0 transmission. To minimize equipment's energy consumption, system makes use of low-power components, managing peripheral state dynamically, switching into idle mode intelligently, pulse-width modulation (PWM) of the NIR LEDs of the depth camera and algorithm optimization by the motion sensor. To test this equipment's function and performance, a gesture recognition algorithm is applied to system. As the result presents, general energy consumption could be as low as 0.5 W.

  6. Redesign of a computerized clinical reminder for colorectal cancer screening: a human-computer interaction evaluation

    Directory of Open Access Journals (Sweden)

    Saleem Jason J

    2011-11-01

    Full Text Available Abstract Background Based on barriers to the use of computerized clinical decision support (CDS learned in an earlier field study, we prototyped design enhancements to the Veterans Health Administration's (VHA's colorectal cancer (CRC screening clinical reminder to compare against the VHA's current CRC reminder. Methods In a controlled simulation experiment, 12 primary care providers (PCPs used prototypes of the current and redesigned CRC screening reminder in a within-subject comparison. Quantitative measurements were based on a usability survey, workload assessment instrument, and workflow integration survey. We also collected qualitative data on both designs. Results Design enhancements to the VHA's existing CRC screening clinical reminder positively impacted aspects of usability and workflow integration but not workload. The qualitative analysis revealed broad support across participants for the design enhancements with specific suggestions for improving the reminder further. Conclusions This study demonstrates the value of a human-computer interaction evaluation in informing the redesign of information tools to foster uptake, integration into workflow, and use in clinical practice.

  7. Controlling a human-computer interface system with a novel classification method that uses electrooculography signals.

    Science.gov (United States)

    Wu, Shang-Lin; Liao, Lun-De; Lu, Shao-Wei; Jiang, Wei-Ling; Chen, Shi-An; Lin, Chin-Teng

    2013-08-01

    Electrooculography (EOG) signals can be used to control human-computer interface (HCI) systems, if properly classified. The ability to measure and process these signals may help HCI users to overcome many of the physical limitations and inconveniences in daily life. However, there are currently no effective multidirectional classification methods for monitoring eye movements. Here, we describe a classification method used in a wireless EOG-based HCI device for detecting eye movements in eight directions. This device includes wireless EOG signal acquisition components, wet electrodes and an EOG signal classification algorithm. The EOG classification algorithm is based on extracting features from the electrical signals corresponding to eight directions of eye movement (up, down, left, right, up-left, down-left, up-right, and down-right) and blinking. The recognition and processing of these eight different features were achieved in real-life conditions, demonstrating that this device can reliably measure the features of EOG signals. This system and its classification procedure provide an effective method for identifying eye movements. Additionally, it may be applied to study eye functions in real-life conditions in the near future.

  8. Impact of familiarity on information complexity in human-computer interfaces

    Directory of Open Access Journals (Sweden)

    Bakaev Maxim

    2016-01-01

    Full Text Available A quantitative measure of information complexity remains very much desirable in HCI field, since it may aid in optimization of user interfaces, especially in human-computer systems for controlling complex objects. Our paper is dedicated to exploration of subjective (subject-depended aspect of the complexity, conceptualized as information familiarity. Although research of familiarity in human cognition and behaviour is done in several fields, the accepted models in HCI, such as Human Processor or Hick-Hyman’s law do not generally consider this issue. In our experimental study the subjects performed search and selection of digits and letters, whose familiarity was conceptualized as frequency of occurrence in numbers and texts. The analysis showed significant effect of information familiarity on selection time and throughput in regression models, although the R2 values were somehow low. Still, we hope that our results might aid in quantification of information complexity and its further application for optimizing interaction in human-machine systems.

  9. How should Fitts' Law be applied to human-computer interaction?

    Science.gov (United States)

    Gillan, D. J.; Holden, K.; Adam, S.; Rudisill, M.; Magee, L.

    1992-01-01

    The paper challenges the notion that any Fitts' Law model can be applied generally to human-computer interaction, and proposes instead that applying Fitts' Law requires knowledge of the users' sequence of movements, direction of movement, and typical movement amplitudes as well as target sizes. Two experiments examined a text selection task with sequences of controlled movements (point-click and point-drag). For the point-click sequence, a Fitts' Law model that used the diagonal across the text object in the direction of pointing (rather than the horizontal extent of the text object) as the target size provided the best fit for the pointing time data, whereas for the point-drag sequence, a Fitts' Law model that used the vertical size of the text object as the target size gave the best fit. Dragging times were fitted well by Fitts' Law models that used either the vertical or horizontal size of the terminal character in the text object. Additional results of note were that pointing in the point-click sequence was consistently faster than in the point-drag sequence, and that pointing in either sequence was consistently faster than dragging. The discussion centres around the need to define task characteristics before applying Fitts' Law to an interface design or analysis, analyses of pointing and of dragging, and implications for interface design.

  10. Appearance-based human gesture recognition using multimodal features for human computer interaction

    Science.gov (United States)

    Luo, Dan; Gao, Hua; Ekenel, Hazim Kemal; Ohya, Jun

    2011-03-01

    The use of gesture as a natural interface plays an utmost important role for achieving intelligent Human Computer Interaction (HCI). Human gestures include different components of visual actions such as motion of hands, facial expression, and torso, to convey meaning. So far, in the field of gesture recognition, most previous works have focused on the manual component of gestures. In this paper, we present an appearance-based multimodal gesture recognition framework, which combines the different groups of features such as facial expression features and hand motion features which are extracted from image frames captured by a single web camera. We refer 12 classes of human gestures with facial expression including neutral, negative and positive meanings from American Sign Languages (ASL). We combine the features in two levels by employing two fusion strategies. At the feature level, an early feature combination can be performed by concatenating and weighting different feature groups, and LDA is used to choose the most discriminative elements by projecting the feature on a discriminative expression space. The second strategy is applied on decision level. Weighted decisions from single modalities are fused in a later stage. A condensation-based algorithm is adopted for classification. We collected a data set with three to seven recording sessions and conducted experiments with the combination techniques. Experimental results showed that facial analysis improve hand gesture recognition, decision level fusion performs better than feature level fusion.

  11. Selection of suitable hand gestures for reliable myoelectric human computer interface.

    Science.gov (United States)

    Castro, Maria Claudia F; Arjunan, Sridhar P; Kumar, Dinesh K

    2015-04-09

    Myoelectric controlled prosthetic hand requires machine based identification of hand gestures using surface electromyogram (sEMG) recorded from the forearm muscles. This study has observed that a sub-set of the hand gestures have to be selected for an accurate automated hand gesture recognition, and reports a method to select these gestures to maximize the sensitivity and specificity. Experiments were conducted where sEMG was recorded from the muscles of the forearm while subjects performed hand gestures and then was classified off-line. The performances of ten gestures were ranked using the proposed Positive-Negative Performance Measurement Index (PNM), generated by a series of confusion matrices. When using all the ten gestures, the sensitivity and specificity was 80.0% and 97.8%. After ranking the gestures using the PNM, six gestures were selected and these gave sensitivity and specificity greater than 95% (96.5% and 99.3%); Hand open, Hand close, Little finger flexion, Ring finger flexion, Middle finger flexion and Thumb flexion. This work has shown that reliable myoelectric based human computer interface systems require careful selection of the gestures that have to be recognized and without such selection, the reliability is poor.

  12. Communication theory

    CERN Document Server

    Goldie, Charles M

    1991-01-01

    This book is an introduction, for mathematics students, to the theories of information and codes. They are usually treated separately but, as both address the problem of communication through noisy channels (albeit from different directions), the authors have been able to exploit the connection to give a reasonably self-contained treatment, relating the probabilistic and algebraic viewpoints. The style is discursive and, as befits the subject, plenty of examples and exercises are provided. Some examples and exercises are provided. Some examples of computer codes are given to provide concrete illustrations of abstract ideas.

  13. Visualizing multi-channel networks

    DEFF Research Database (Denmark)

    Antemijczuk, Paweł; Magiera, Marta; Jørgensen, Sune Lehmann

    2014-01-01

    In this paper, we propose a visualization to illustrate social interactions, built from multiple distinct channels of communication. The visualization displays a summary of dense personal information in a compact graphical notation. The starting point is an abstract drawing of a spider’s web. Below...

  14. Augmentative And Alternative Communication Systems For Post-Stroke Patients With Severe Communication And Motor Impairment

    Directory of Open Access Journals (Sweden)

    Talieh Zarifian

    2017-02-01

    Full Text Available Background and aims: Adults with acquired neurological disorders (stroke, Traumatic Brain Injury ... develop their verbal communication and literacy capabilities as typical speakers and writers. They use these skills to participate academically, vocationally, recreationally, and socially. Depending upon their neurological condition, they gradually or suddenly lose their speech or language capabilities and are required to rely on Augmentative and Alternative Communication (AAC systems to meet their communication needs. In addition to the loss of their spoken communication, the impact of their neurological condition on their participation patterns is potentially profound with reduced ability to care for themselves, a reduction or loss of employment, and usually a sudden or gradual restriction of their social networks. AAC is an umbrella term that encompasses the communication methods used to supplement or replace speech or writing for those with impairments in the production or comprehension of spoken or written language. During the past five decades, AAC technologies have been developed to compensate for these natural communication losses.      Stroke is one of the main causes of disability in the world. About 20% of stroke patients experience aphasia, with 20-30% of these individuals exhibiting severe communication deficits for at least a portion of their recovery period. Augmentative and Alternative Communication (AAC encompasses the communication methods used to supplement or replace speech or writing for those with impairments in the production of spoken or written language.  Specifically designed Human Computer Interfaces (HCI, as an assistive technology, provides new channels of communication for patients with aphasia, dysarthria, and dyspraxia, when accompanied by movement impairments.       In this workshop after stating a science review of the following types of issues: AAC acceptance (individually, culturally; AAC availability

  15. Quantum Secure Direct Communication Using W State

    International Nuclear Information System (INIS)

    Dong Li; Xiu Xiaoming; Gao Yajun; Chi Feng

    2008-01-01

    A theoretical scheme of quantum secure direct communication using teleportation is proposed. In the scheme, the sender needs to prepare a class of three-particle W states to use as quantum channel. The two communicators may communicate after they test the security of the quantum channel. The security of the protocol is ensured by quantum entanglement and quantum no-cloning theorem. The receiver can obtain the secret message determinately if the quantum channel is secure

  16. 47 CFR 101.1405 - Channeling plan.

    Science.gov (United States)

    2010-10-01

    ... 47 Telecommunication 5 2010-10-01 2010-10-01 false Channeling plan. 101.1405 Section 101.1405 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) SAFETY AND SPECIAL RADIO SERVICES FIXED MICROWAVE... Channeling plan. Each license shall have one spectrum block of 500 megahertz per geographic area that can be...

  17. A Novel Wearable Forehead EOG Measurement System for Human Computer Interfaces

    OpenAIRE

    Heo, Jeong; Yoon, Heenam; Park, Kwang Suk

    2017-01-01

    Amyotrophic lateral sclerosis (ALS) patients whose voluntary muscles are paralyzed commonly communicate with the outside world using eye movement. There have been many efforts to support this method of communication by tracking or detecting eye movement. An electrooculogram (EOG), an electro-physiological signal, is generated by eye movements and can be measured with electrodes placed around the eye. In this study, we proposed a new practical electrode position on the forehead to measure EOG ...

  18. Human Computer Confluence in Rehabilitation: Digital Media Plasticity and Human Performance Plasticity

    DEFF Research Database (Denmark)

    Brooks, Anthony Lewis

    2013-01-01

    Digital media plasticity evocative to embodied interaction is presented as a utilitarian tool when mixed and matched to target human performance potentials specific to nuance of development for those with impairment. A distinct intervention strategy trains via alternative channeling of external s...

  19. Channel Power in Multi-Channel Environments

    NARCIS (Netherlands)

    M.G. Dekimpe (Marnik); B. Skiera (Bernd)

    2004-01-01

    textabstractIn the literature, little attention has been paid to instances where companies add an Internet channel to their direct channel portfolio. However, actively managing multiple sales channels requires knowing the customers’ channel preferences and the resulting channel power. Two key

  20. Aerosol optical properties derived from the DRAGON-NE Asia campaign, and implications for a single-channel algorithm to retrieve aerosol optical depth in spring from Meteorological Imager (MI on-board the Communication, Ocean, and Meteorological Satellite (COMS

    Directory of Open Access Journals (Sweden)

    M. Kim

    2016-02-01

    Full Text Available An aerosol model optimized for northeast Asia is updated with the inversion data from the Distributed Regional Aerosol Gridded Observation Networks (DRAGON-northeast (NE Asia campaign which was conducted during spring from March to May 2012. This updated aerosol model was then applied to a single visible channel algorithm to retrieve aerosol optical depth (AOD from a Meteorological Imager (MI on-board the geostationary meteorological satellite, Communication, Ocean, and Meteorological Satellite (COMS. This model plays an important role in retrieving accurate AOD from a single visible channel measurement. For the single-channel retrieval, sensitivity tests showed that perturbations by 4 % (0.926 ± 0.04 in the assumed single scattering albedo (SSA can result in the retrieval error in AOD by over 20 %. Since the measured reflectance at the top of the atmosphere depends on both AOD and SSA, the overestimation of assumed SSA in the aerosol model leads to an underestimation of AOD. Based on the AErosol RObotic NETwork (AERONET inversion data sets obtained over East Asia before 2011, seasonally analyzed aerosol optical properties (AOPs were categorized by SSAs at 675 nm of 0.92 ± 0.035 for spring (March, April, and May. After the DRAGON-NE Asia campaign in 2012, the SSA during spring showed a slight increase to 0.93 ± 0.035. In terms of the volume size distribution, the mode radius of coarse particles was increased from 2.08 ± 0.40 to 2.14 ± 0.40. While the original aerosol model consists of volume size distribution and refractive indices obtained before 2011, the new model is constructed by using a total data set after the DRAGON-NE Asia campaign. The large volume of data in high spatial resolution from this intensive campaign can be used to improve the representative aerosol model for East Asia. Accordingly, the new AOD data sets retrieved from a single-channel algorithm, which uses a precalculated look-up table (LUT with the new aerosol model

  1. Aerosol Optical Properties Derived from the DRAGON-NE Asia Campaign, and Implications for a Single-Channel Algorithm to Retrieve Aerosol Optical Depth in Spring from Meteorological Imager (MI) On-Board the Communication, Ocean, and Meteorological Satellite (COMS)

    Science.gov (United States)

    Kim, M.; Kim, J.; Jeong, U.; Kim, W.; Hong, H.; Holben, B.; Eck, T. F.; Lim, J.; Song, C.; Lee, S.; hide

    2016-01-01

    An aerosol model optimized for northeast Asia is updated with the inversion data from the Distributed Regional Aerosol Gridded Observation Networks (DRAGON)-northeast (NE) Asia campaign which was conducted during spring from March to May 2012. This updated aerosol model was then applied to a single visible channel algorithm to retrieve aerosol optical depth (AOD) from a Meteorological Imager (MI) on-board the geostationary meteorological satellite, Communication, Ocean, and Meteorological Satellite (COMS). This model plays an important role in retrieving accurate AOD from a single visible channel measurement. For the single-channel retrieval, sensitivity tests showed that perturbations by 4 % (0.926 +/- 0.04) in the assumed single scattering albedo (SSA) can result in the retrieval error in AOD by over 20 %. Since the measured reflectance at the top of the atmosphere depends on both AOD and SSA, the overestimation of assumed SSA in the aerosol model leads to an underestimation of AOD. Based on the AErosol RObotic NETwork (AERONET) inversion data sets obtained over East Asia before 2011, seasonally analyzed aerosol optical properties (AOPs) were categorized by SSAs at 675 nm of 0.92 +/- 0.035 for spring (March, April, and May). After the DRAGON-NE Asia campaign in 2012, the SSA during spring showed a slight increase to 0.93 +/- 0.035. In terms of the volume size distribution, the mode radius of coarse particles was increased from 2.08 +/- 0.40 to 2.14 +/- 0.40. While the original aerosol model consists of volume size distribution and refractive indices obtained before 2011, the new model is constructed by using a total data set after the DRAGON-NE Asia campaign. The large volume of data in high spatial resolution from this intensive campaign can be used to improve the representative aerosol model for East Asia. Accordingly, the new AOD data sets retrieved from a single-channel algorithm, which uses a precalculated look-up table (LUT) with the new aerosol model, show

  2. Physical and mathematical models of communication systems

    International Nuclear Information System (INIS)

    Verkhovskaya, E.P.; Yavorskij, V.V.

    2006-01-01

    The theoretical parties connecting resources of communication system with characteristics of channels are received. The model of such systems from positions quasi-classical thermodynamics is considered. (author)

  3. Covert Channel Pada Aliran Data Websocket untuk Komunikasi Messaging XMPP

    Directory of Open Access Journals (Sweden)

    Yoga Dwitya Pramudita

    2015-07-01

    Abstract Instant Messaging communication services provide a variety of communication features that can be used by the user, such as text messaging (text messages both online and offline. One of the standard protocol that supports this service is XMPP (Extensible Messaging and Presence Protocol. XMPP communication using XML documents, making it vulnerable to passive attacks monitoring content of  communications. To overcome this drawback the solution is encrypted communications. The other solutions that try to offer in this research is the use of a covert channel to send hidden messages. In this research will create a browser based XMPP client application that is capable to deliver XMPP communication and also provide covert channel communication. XMPP communication can be built on a web-based application using WebSocket protocol. This protocol will exploit field masking-key to load the covert channel messages that is sent during the session XMPP communication takes place. From the test results, the client application is able to produce a covert channel communication with a data width of 3 bytes in each packet. The client application is also able to perform covert communication channel in a communication link with the condition of the probability of packet loss rate below 10%.   Keywords— WebSocket, XMPP, masking-key, Covert Channel, browser based application.

  4. Principles of digital communication and coding

    CERN Document Server

    Viterbi, Andrew J

    2009-01-01

    This classic by two digital communications experts is geared toward students of communications theory and to designers of channels, links, terminals, modems, or networks used to transmit and receive digital messages. 1979 edition.

  5. Clock Management Data Analysis for Satellite Communications

    National Research Council Canada - National Science Library

    Gross, Rachel; Melkers, Raimond

    2005-01-01

    The U.S. Naval Research Laboratory has installed GPS-based timing systems in several Defense Satellite Communication System "DSCS-III" satellite communication facilities to support the Single Channel Transponder "SCT" program...

  6. Performance Limits of Communication with Energy Harvesting

    KAUST Repository

    Znaidi, Mohamed Ridha

    2016-01-01

    In energy harvesting communications, the transmitters have to adapt transmission to the availability of energy harvested during communication. The performance of the transmission depends on the channel conditions which vary randomly due to mobility

  7. Wire communication engineering

    International Nuclear Information System (INIS)

    Son, Byeong Tae

    1997-02-01

    This book describes wire telecommunication engineering/ It is divided into eleven chapter, which deal with Introduction with development of telecommunication, voice and sound wave and communication network, Telegraphy with summary of telegraphy, code of telegraphy, communication speed, morse and telex, Telephone on structure, circuit and image telephone, Traffic on telecommunication traffic, transmission of line about theory, cable line and loaded cable, carrier communication with carrier telegraphy and carrier telephone, optical communication with types, structure, specialty, laser and equipment, DATA, Mobile telecommunication on summary, mobile telephone, radio paging and digital mobile telecommunication, ISDN with channel of ISDN, and service of ISDN, and design of telecommunication.

  8. Mobile communication and intermediality

    DEFF Research Database (Denmark)

    Helles, Rasmus

    2013-01-01

    communicative affordances of mobile devices in order to understand how people choose between them for different purposes. It is argued that mobile communication makes intermediality especially central, as the choice of medium is detached from the location of stationary media and begins to follow the user across......The article argues the importance of intermediality as a concept for research in mobile communication and media. The constant availability of several, partially overlapping channels for communication (texting, calls, email, Facebook, etc.) requires that we adopt an integrated view of the various...

  9. Quantum channels with a finite memory

    International Nuclear Information System (INIS)

    Bowen, Garry; Mancini, Stefano

    2004-01-01

    In this paper we study quantum communication channels with correlated noise effects, i.e., quantum channels with memory. We derive a model for correlated noise channels that includes a channel memory state. We examine the case where the memory is finite, and derive bounds on the classical and quantum capacities. For the entanglement-assisted and unassisted classical capacities it is shown that these bounds are attainable for certain classes of channel. Also, we show that the structure of any finite-memory state is unimportant in the asymptotic limit, and specifically, for a perfect finite-memory channel where no information is lost to the environment, achieving the upper bound implies that the channel is asymptotically noiseless

  10. A Conceptual Architecture for Adaptive Human-Computer Interface of a PT Operation Platform Based on Context-Awareness

    Directory of Open Access Journals (Sweden)

    Qing Xue

    2014-01-01

    Full Text Available We present a conceptual architecture for adaptive human-computer interface of a PT operation platform based on context-awareness. This architecture will form the basis of design for such an interface. This paper describes components, key technologies, and working principles of the architecture. The critical contents covered context information modeling, processing, relationship establishing between contexts and interface design knowledge by use of adaptive knowledge reasoning, and visualization implementing of adaptive interface with the aid of interface tools technology.

  11. Historical Overview, Current Status, and Future Trends in Human-Computer Interfaces for Process Control

    International Nuclear Information System (INIS)

    Owre, Fridtjov

    2003-01-01

    Approximately 25 yr ago, the first computer-based process control systems, including computer-generated displays, appeared. It is remarkable how slowly the human-computer interfaces (HCI's) of such systems have developed over the years. The display design approach in those early days had its roots in the topology of the process. Usually, the information came from the piping and instrumentation diagrams. Later, some important additional functions were added to the basic system, such as alarm and trend displays. Today, these functions are still the basic ones, and the end-user displays have not changed much except for improved display quality in terms of colors, font types and sizes, resolution, and object shapes, resulting from improved display hardware.Today, there are two schools of display design competing for supremacy in the process control segment of the HCI community. One can be characterized by extension and integration of current practice, while the other is more revolutionary.The extension of the current practice approach can be described in terms of added system functionality and integration. This means that important functions for the plant operator - such as signal validation, plant overview information, safety parameter displays, procedures, prediction of future states, and plant performance optimization - are added to the basic functions and integrated in a total unified HCI for the plant operator.The revolutionary approach, however, takes as its starting point the design process itself. The functioning of the plant is described in terms of the plant goals and subgoals, as well as the means available to reach these goals. Then, displays are designed representing this functional structure - in clear contrast to the earlier plant topology representation. Depending on the design approach used, the corresponding displays have various designations, e.g., function-oriented, task-oriented, or ecological displays.This paper gives a historical overview of past

  12. Ontology for assessment studies of human-computer-interaction in surgery.

    Science.gov (United States)

    Machno, Andrej; Jannin, Pierre; Dameron, Olivier; Korb, Werner; Scheuermann, Gerik; Meixensberger, Jürgen

    2015-02-01

    New technologies improve modern medicine, but may result in unwanted consequences. Some occur due to inadequate human-computer-interactions (HCI). To assess these consequences, an investigation model was developed to facilitate the planning, implementation and documentation of studies for HCI in surgery. The investigation model was formalized in Unified Modeling Language and implemented as an ontology. Four different top-level ontologies were compared: Object-Centered High-level Reference, Basic Formal Ontology, General Formal Ontology (GFO) and Descriptive Ontology for Linguistic and Cognitive Engineering, according to the three major requirements of the investigation model: the domain-specific view, the experimental scenario and the representation of fundamental relations. Furthermore, this article emphasizes the distinction of "information model" and "model of meaning" and shows the advantages of implementing the model in an ontology rather than in a database. The results of the comparison show that GFO fits the defined requirements adequately: the domain-specific view and the fundamental relations can be implemented directly, only the representation of the experimental scenario requires minor extensions. The other candidates require wide-ranging extensions, concerning at least one of the major implementation requirements. Therefore, the GFO was selected to realize an appropriate implementation of the developed investigation model. The ensuing development considered the concrete implementation of further model aspects and entities: sub-domains, space and time, processes, properties, relations and functions. The investigation model and its ontological implementation provide a modular guideline for study planning, implementation and documentation within the area of HCI research in surgery. This guideline helps to navigate through the whole study process in the form of a kind of standard or good clinical practice, based on the involved foundational frameworks

  13. Optimal design methods for a digital human-computer interface based on human reliability in a nuclear power plant

    International Nuclear Information System (INIS)

    Jiang, Jianjun; Zhang, Li; Xie, Tian; Wu, Daqing; Li, Min; Wang, Yiqun; Peng, Yuyuan; Peng, Jie; Zhang, Mengjia; Li, Peiyao; Ma, Congmin; Wu, Xing

    2017-01-01

    Highlights: • A complete optimization process is established for digital human-computer interfaces of Npps. • A quick convergence search method is proposed. • The authors propose an affinity error probability mapping function to test human reliability. - Abstract: This is the second in a series of papers describing the optimal design method for a digital human-computer interface of nuclear power plant (Npp) from three different points based on human reliability. The purpose of this series is to explore different optimization methods from varying perspectives. This present paper mainly discusses the optimal design method for quantity of components of the same factor. In monitoring process, quantity of components has brought heavy burden to operators, thus, human errors are easily triggered. To solve the problem, the authors propose an optimization process, a quick convergence search method and an affinity error probability mapping function. Two balanceable parameter values of the affinity error probability function are obtained by experiments. The experimental results show that the affinity error probability mapping function about human-computer interface has very good sensitivity and stability, and that quick convergence search method for fuzzy segments divided by component quantity has better performance than general algorithm.

  14. Investigation Of Information Sources And Communication Channels ...

    African Journals Online (AJOL)

    Extension of integrated pest management (IPM) as a component of sustainable agricultural development, involves empowering farmers. Facilitating the information accessibility of farmer groups seems as empowerment strategy. This strategy is based on identification of related patterns, including information sources and ...

  15. Design Science in Human-Computer Interaction: A Model and Three Examples

    Science.gov (United States)

    Prestopnik, Nathan R.

    2013-01-01

    Humanity has entered an era where computing technology is virtually ubiquitous. From websites and mobile devices to computers embedded in appliances on our kitchen counters and automobiles parked in our driveways, information and communication technologies (ICTs) and IT artifacts are fundamentally changing the ways we interact with our world.…

  16. Brain-Computer Interfaces. Applying our Minds to Human-Computer Interaction

    NARCIS (Netherlands)

    Tan, Desney S.; Nijholt, Antinus

    2010-01-01

    For generations, humans have fantasized about the ability to create devices that can see into a person’s mind and thoughts, or to communicate and interact with machines through thought alone. Such ideas have long captured the imagination of humankind in the form of ancient myths and modern science

  17. Channel coding in the space station data system network

    Science.gov (United States)

    Healy, T.

    1982-01-01

    A detailed discussion of the use of channel coding for error correction, privacy/secrecy, channel separation, and synchronization is presented. Channel coding, in one form or another, is an established and common element in data systems. No analysis and design of a major new system would fail to consider ways in which channel coding could make the system more effective. The presence of channel coding on TDRS, Shuttle, the Advanced Communication Technology Satellite Program system, the JSC-proposed Space Operations Center, and the proposed 30/20 GHz Satellite Communication System strongly support the requirement for the utilization of coding for the communications channel. The designers of the space station data system have to consider the use of channel coding.

  18. Channelling and electromagnetic radiation of channelling particles

    International Nuclear Information System (INIS)

    Kalashnikov, N.

    1983-01-01

    A brief description is presented of the channelling of charged particles between atoms in the crystal lattice. The specificities are discussed of the transverse motion of channelling particles as are the origin and properties of quasi-characteristic radiation of channelling particles which accompany transfers from one band of permissible energies of the transverse motion of channelling particles to the other. (B.S.)

  19. The sciences of science communication.

    Science.gov (United States)

    Fischhoff, Baruch

    2013-08-20

    The May 2012 Sackler Colloquium on "The Science of Science Communication" brought together scientists with research to communicate and scientists whose research could facilitate that communication. The latter include decision scientists who can identify the scientific results that an audience needs to know, from among all of the scientific results that it would be nice to know; behavioral scientists who can design ways to convey those results and then evaluate the success of those attempts; and social scientists who can create the channels needed for trustworthy communications. This overview offers an introduction to these communication sciences and their roles in science-based communication programs.

  20. Brand Communication in a Digitalized World

    Directory of Open Access Journals (Sweden)

    Kecskes Robert

    2017-11-01

    Full Text Available The way in which we communicate is changing radically. In the analog world, promotional communication was consumed rather passively. In today’s digital age, consumers have become more active. Especially, the younger consumer generation - referred to as iBrains- are increasingly spreading their own product experiences across digital channels into the virtual world. Stimulus-response communication still has its place, but must be supplemented with interactive offers that enable a dialogue with consumers. Diverse communication channels must be utilized - analog as well as digital - in order to reach the young target groups. As consumers tend to be “always on”, they use different communication channels simultaneously, leading to continuous partial attention. Therefore, not only new channels are necessary but the entire communication style and design need to be adapted. It is not enough to simply make contact. Instead of thinking about shortening the message, creativity should be put into creatively combining different building blocks of communication.

  1. Channeling experiment

    International Nuclear Information System (INIS)

    Abelin, H.; Birgersson, L.; Widen, H.; Aagren, T.; Moreno, L.; Neretnieks, I.

    1990-07-01

    Channeling of water flow and tracer transport in real fractures in a granite body at Stripa have been investigated experimentally. The experimental site was located 360 m below the ground level. Two kinds of experiments were performed. In the single hole experiments, 20 cm diameter holes were drilled about 2.5 m into the rock in the plane of the fracture. Specially designed packers were used to inject water into the fracture in 5 cm intervals all along the fracture trace in the hole. The variation of the injection flowrates along the fracture were used to determine the transmissivity variations in the fracture plane. Detailed photographs were taken from inside the hole and the visual fracture aperture was compared with the injection flowrates in the same locations. Geostatistical methods were used to evaluate the results. Five holes were measured in great detail. In addition 7 holes were drilled and scanned by simpler packer systems. A double hole experiment was performed where two parallel holes were drilled in the same fracture plane at nearly 2 m distance. Pressure pulse tests were made between the holes in both directions. Tracers were injected in 5 locations in one hole and monitored for in many locations in the other hole. The single hole experiment and the double hole experiment show that most of the fracture planes are tight but that there are open sections which form connected channels over distances of at least 2 meters. It was also found in the double hole experiment that the investigated fracture was intersected by at least one fracture between the two holes which diverted a large amount of the injected tracers to several distant locations at the tunnel wall. (authours)

  2. Digital Communication and Modulation

    DEFF Research Database (Denmark)

    Sørensen, John Aasted

    2011-01-01

    system. Having passed the course, the student will be able to accomplish the following, within the areas shown below: Model for Communication System. Prepare and explain the functional block in a digital communication system, corresponding to the specific course contents. Model for Communication Channel...... system.   Sessions in class with active participation by the students. The time will be divided between lectures and the students solving problems, including simulating digital communication building blocks in Matlab. Combines lectures and hands-on work. Semester: E2011 Extent: 7.5 ects......, the fundamental principles for modulation and detection in Gaussian noise is treated. This includes the principles for the determination of the bit-error rate for a digital communication system. During the course, a selection of small Matlab exercises are prepared, for simulation of parts of a communication...

  3. Digital Communication and Modulation

    DEFF Research Database (Denmark)

    Sørensen, John Aasted

    2011-01-01

    system. Having passed the course, the student will be able to accomplish the following, within the areas shown below: Model for Communication System. Prepare and explain the functional block in a digital communication system, corresponding to the specific course contents. Model for Communication Channel...... system. Sessions in class with active participation by the students. The time will be divided between lectures and the students solving problems, including simulating digital communication building blocks in Matlab. Combines lectures and hands-on work. Semester: F2011 Extent: 7.5 ects......, the fundamental principles for modulation and detection in Gaussian noise is treated. This includes the principles for the determination of the bit-error rate for a digital communication system. During the course, a selection of small Matlab exercises are prepared, for simulation of parts of a communication...

  4. 3rd International Conference on Computer & Communication Technologies

    CERN Document Server

    Bhateja, Vikrant; Raju, K; Janakiramaiah, B

    2017-01-01

    The book is a compilation of high-quality scientific papers presented at the 3rd International Conference on Computer & Communication Technologies (IC3T 2016). The individual papers address cutting-edge technologies and applications of soft computing, artificial intelligence and communication. In addition, a variety of further topics are discussed, which include data mining, machine intelligence, fuzzy computing, sensor networks, signal and image processing, human-computer interaction, web intelligence, etc. As such, it offers readers a valuable and unique resource.

  5. Preface for the book: Antennas And Propagation for Body-Centric Wireless Communications

    DEFF Research Database (Denmark)

    Frederiksen, Flemming Bjerge; Prasad, Ramjee

    2006-01-01

    The book address the following subjects: Body Centric Wireless Communications possibilities, Electromagnetic properties of the body, On-body Communication Channels at high and low frequency bands, Body Centric UWB Communications, Wearable Antennas for cellular and WLAN communications, Body...

  6. Expected number of quantum channels in quantum networks

    Science.gov (United States)

    Chen, Xi; Wang, He-Ming; Ji, Dan-Tong; Mu, Liang-Zhu; Fan, Heng

    2015-07-01

    Quantum communication between nodes in quantum networks plays an important role in quantum information processing. Here, we proposed the use of the expected number of quantum channels as a measure of the efficiency of quantum communication for quantum networks. This measure quantified the amount of quantum information that can be teleported between nodes in a quantum network, which differs from classical case in that the quantum channels will be consumed if teleportation is performed. We further demonstrated that the expected number of quantum channels represents local correlations depicted by effective circles. Significantly, capacity of quantum communication of quantum networks quantified by ENQC is independent of distance for the communicating nodes, if the effective circles of communication nodes are not overlapped. The expected number of quantum channels can be enhanced through transformations of the lattice configurations of quantum networks via entanglement swapping. Our results can shed lights on the study of quantum communication in quantum networks.

  7. Reliability Improved Design for a Safety System Channel

    International Nuclear Information System (INIS)

    Oh, Eung Se; Kim, Yun Goo

    2016-01-01

    Nowadays, these systems are implemented with a same platform type, such as a qualified programmable logic controller (PLC). The platform intensively uses digital communication with fiber-optic links to reduce cabling costs and to achieve effective signal isolation. These communication interface and redundancies within a channel increase the complexness of an overall system design. This paper proposes a simpler channel architecture design to reduce the complexity and to enhance overall channel reliability. Simplified safety channel configuration is proposed and the failure probabilities are compared with baseline safety channel configuration using an estimated generic value. The simplified channel configuration achieves 40 percent failure reduction compare to baseline safety channel configuration. If this configuration can be implemented within a processor module, overall safety channel reliability is increase and costs of fabrication and maintenance will be greatly reduced

  8. Reliability Improved Design for a Safety System Channel

    Energy Technology Data Exchange (ETDEWEB)

    Oh, Eung Se; Kim, Yun Goo [KHNP, Daejeon (Korea, Republic of)

    2016-05-15

    Nowadays, these systems are implemented with a same platform type, such as a qualified programmable logic controller (PLC). The platform intensively uses digital communication with fiber-optic links to reduce cabling costs and to achieve effective signal isolation. These communication interface and redundancies within a channel increase the complexness of an overall system design. This paper proposes a simpler channel architecture design to reduce the complexity and to enhance overall channel reliability. Simplified safety channel configuration is proposed and the failure probabilities are compared with baseline safety channel configuration using an estimated generic value. The simplified channel configuration achieves 40 percent failure reduction compare to baseline safety channel configuration. If this configuration can be implemented within a processor module, overall safety channel reliability is increase and costs of fabrication and maintenance will be greatly reduced.

  9. Communication without communication

    Directory of Open Access Journals (Sweden)

    Bratina Boris R.

    2017-01-01

    Full Text Available This paper analyses the necessary conditions for successful communication. It is well known that post-modernity, described as an era of control, produces only decentralized, imploded subjectivities, who are neither able to question their own being nor to relate one with another in authentic bonds of communication. Today, virtual communication has become an ultimate model of every possible communication whatsoever. The authors, therefore, pose the question of conditions for possibility of subjectivities who would be able and apt for authentic communication, wherein faith, fidelity, truth, and capability of keeping one's word occupy the central place.

  10. Brain-Computer Interfaces Applying Our Minds to Human-computer Interaction

    CERN Document Server

    Tan, Desney S

    2010-01-01

    For generations, humans have fantasized about the ability to create devices that can see into a person's mind and thoughts, or to communicate and interact with machines through thought alone. Such ideas have long captured the imagination of humankind in the form of ancient myths and modern science fiction stories. Recent advances in cognitive neuroscience and brain imaging technologies have started to turn these myths into a reality, and are providing us with the ability to interface directly with the human brain. This ability is made possible through the use of sensors that monitor physical p

  11. Signal processing for mobile communications handbook

    CERN Document Server

    Ibnkahla, Mohamed

    2004-01-01

    INTRODUCTIONSignal Processing for Future Mobile Communications Systems: Challenges and Perspectives; Quazi Mehbubar Rahman and Mohamed IbnkahlaCHANNEL MODELING AND ESTIMATIONMultipath Propagation Models for Broadband Wireless Systems; Andreas F. Molisch and Fredrik TufvessonModeling and Estimation of Mobile Channels; Jitendra K. TugnaitMobile Satellite Channels: Statistical Models and Performance Analysis; Giovanni E. Corazza, Alessandro Vanelli-Coralli, Raffaella Pedone, and Massimo NeriMobile Velocity Estimation for Wireless Communications; Bouchra Senadji, Ghazem Azemi, and Boualem Boashash

  12. Digital and analog communication systems

    Science.gov (United States)

    Shanmugam, K. S.

    1979-01-01

    The book presents an introductory treatment of digital and analog communication systems with emphasis on digital systems. Attention is given to the following topics: systems and signal analysis, random signal theory, information and channel capacity, baseband data transmission, analog signal transmission, noise in analog communication systems, digital carrier modulation schemes, error control coding, and the digital transmission of analog signals.

  13. Quantum cryptography communication technology

    International Nuclear Information System (INIS)

    Cho, Jai Wan; Choi, Young Soo; Lee, Jae Chul; Choi, Yu Rak; Jung, Gwang Il; Jung, Jong Eun; Hong, Seok Boong; Koo, In Soo

    2007-09-01

    Quantum cryptography communication based on quantum mechanics provides and unconditional security between two users. Even though huge advance has been done since the 1984, having a complete system is still far away. In the case of real quantum cryptography communication systems, an unconditional security level is lowered by the imperfection of the communication unit. It is important to investigate the unconditional security of quantum communication protocols based on these experimental results and implementation examples for the advanced spread all over the world. The Japanese report, titled, 'Investigation report on the worldwide trends of quantum cryptography communications systems' was translated and summarized in this report. An unconditional security theory of the quantum cryptography and real implementation examples in the domestic area are investigated also. The goal of the report is to make quantum cryptography communication more useful and reliable alternative telecommunication infrastructure as the one of the cyber security program of the class 1-E communication system of nuclear power plant. Also another goal of this report is to provide the quantitative decision basis on the quantum cryptography communication when this secure communication system will be used in class 1-E communication channel of the nuclear power plant

  14. Quantum cryptography communication technology

    Energy Technology Data Exchange (ETDEWEB)

    Cho, Jai Wan; Choi, Young Soo; Lee, Jae Chul; Choi, Yu Rak; Jung, Gwang Il; Jung, Jong Eun; Hong, Seok Boong; Koo, In Soo

    2007-09-15

    Quantum cryptography communication based on quantum mechanics provides and unconditional security between two users. Even though huge advance has been done since the 1984, having a complete system is still far away. In the case of real quantum cryptography communication systems, an unconditional security level is lowered by the imperfection of the communication unit. It is important to investigate the unconditional security of quantum communication protocols based on these experimental results and implementation examples for the advanced spread all over the world. The Japanese report, titled, 'Investigation report on the worldwide trends of quantum cryptography communications systems' was translated and summarized in this report. An unconditional security theory of the quantum cryptography and real implementation examples in the domestic area are investigated also. The goal of the report is to make quantum cryptography communication more useful and reliable alternative telecommunication infrastructure as the one of the cyber security program of the class 1-E communication system of nuclear power plant. Also another goal of this report is to provide the quantitative decision basis on the quantum cryptography communication when this secure communication system will be used in class 1-E communication channel of the nuclear power plant.

  15. Communication: I like

    CERN Multimedia

    Staff Association

    2015-01-01

    To fulfill its mission to represent CERN personnel with the Management and the Member States, the Staff Council has set up a series of Commissions: employment conditions, pensions, legal matters, social protection, health and safety, InformAction, CAPA (individual cases) and, more recently, Media-Com. As its name suggests the Media-Com Commission deals with all matters of communication. The mandate of the new Commission is to implement and optimize the communication channels that the Staff Association uses to keep you informed. To attract the greatest number of people, Media-Com operates through multiple communication channels, such as articles in the Echo, the Staff Association information bulletin, the Staff Association website (http://staff- association.web.cern.ch/), Facebook, and, more recently, the intra-CERN Social platform. The Social platform is a discussion forum, for exchanging ideas, expressing views, reacting to, and commenting on current events of the Staff Association. To participa...

  16. The interaction between digital marketing communication and customer loyalty

    OpenAIRE

    Merisavo, Marko

    2008-01-01

    Digital channels and information technology are changing the way that companies communicate and maintain relationships with their customers. The Internet, email, mobile phones, digital TV, and other evolving channels offer opportunities for frequent, costeffective, personalized, and interactive communication between the company and their customers. In addition to traditional offers and persuasion, customers can be provided with relational communication like newsletters, usage tips, maintenanc...

  17. Quality of human-computer interaction - results of a national usability survey of hospital-IT in Germany

    Directory of Open Access Journals (Sweden)

    Bundschuh Bettina B

    2011-11-01

    Full Text Available Abstract Background Due to the increasing functionality of medical information systems, it is hard to imagine day to day work in hospitals without IT support. Therefore, the design of dialogues between humans and information systems is one of the most important issues to be addressed in health care. This survey presents an analysis of the current quality level of human-computer interaction of healthcare-IT in German hospitals, focused on the users' point of view. Methods To evaluate the usability of clinical-IT according to the design principles of EN ISO 9241-10 the IsoMetrics Inventory, an assessment tool, was used. The focus of this paper has been put on suitability for task, training effort and conformity with user expectations, differentiated by information systems. Effectiveness has been evaluated with the focus on interoperability and functionality of different IT systems. Results 4521 persons from 371 hospitals visited the start page of the study, while 1003 persons from 158 hospitals completed the questionnaire. The results show relevant variations between different information systems. Conclusions Specialised information systems with defined functionality received better assessments than clinical information systems in general. This could be attributed to the improved customisation of these specialised systems for specific working environments. The results can be used as reference data for evaluation and benchmarking of human computer engineering in clinical health IT context for future studies.

  18. Coherent communication with continuous quantum variables

    Science.gov (United States)

    Wilde, Mark M.; Krovi, Hari; Brun, Todd A.

    2007-06-01

    The coherent bit (cobit) channel is a resource intermediate between classical and quantum communication. It produces coherent versions of teleportation and superdense coding. We extend the cobit channel to continuous variables by providing a definition of the coherent nat (conat) channel. We construct several coherent protocols that use both a position-quadrature and a momentum-quadrature conat channel with finite squeezing. Finally, we show that the quality of squeezing diminishes through successive compositions of coherent teleportation and superdense coding.

  19. Mapping out the customer’s journey : customer search strategy as a basis for channel management

    NARCIS (Netherlands)

    Drs Robert van Ossenbruggen; Dr. Gerrita van der Veen

    2015-01-01

    Many companies tailor their communication and interaction with customers by segmenting them into channel usage groups. This study argues that simply focusing on channels has limited effectiveness as increasingly customers today use multiple channels, the online channel contains many different forms,

  20. Fiber Optic Communications Technology. A Status Report.

    Science.gov (United States)

    Hull, Joseph A.

    Fiber optic communications (communications over very pure glass transmission channels of diameter comparable to a human hair) is an emerging technology which promises most improvements in communications capacity at reasonable cost. The fiber transmission system offers many desirable characteristics representing improvements over conventional…