High-Bandwidth Tactical-Network Data Analysis in a High-Performance-Computing (HPC) Environment: Voice Call Analysis

DTIC Science & Technology

2015-09-01

Gateway 2 4. Voice Packet Flow: SIP , Session Description Protocol (SDP), and RTP 3 5. Voice Data Analysis 5 6. Call Analysis 6 7. Call Metrics 6...analysis processing is designed for a general VoIP system architecture based on Session Initiation Protocol ( SIP ) for negotiating call sessions and...employs Skinny Client Control Protocol for network communication between the phone and the local CallManager (e.g., for each dialed digit), SIP

Cooperative Spatial Retreat for Resilient Drone Networks.

PubMed

Kang, Jin-Hyeok; Kwon, Young-Min; Park, Kyung-Joon

2017-05-03

Drones are broadening their scope to various applications such as networking, package delivery, agriculture, rescue, and many more. For proper operation of drones, reliable communication should be guaranteed because drones are remotely controlled. When drones experience communication failure due to bad channel condition, interference, or jamming in a certain area, one existing solution is to exploit mobility or so-called spatial retreat to evacuate them from the communication failure area. However, the conventional spatial retreat scheme moves drones in random directions, which results in inefficient movement with significant evacuation time and waste of battery lifetime. In this paper, we propose a novel spatial retreat technique that takes advantage of cooperation between drones for resilient networking, which is called cooperative spatial retreat (CSR). Our performance evaluation shows that the proposed CSR significantly outperforms existing schemes.

Neural network for control of rearrangeable Clos networks.

PubMed

Park, Y K; Cherkassky, V

1994-09-01

Rapid evolution in the field of communication networks requires high speed switching technologies. This involves a high degree of parallelism in switching control and routing performed at the hardware level. The multistage crossbar networks have always been attractive to switch designers. In this paper a neural network approach to controlling a three-stage Clos network in real time is proposed. This controller provides optimal routing of communication traffic requests on a call-by-call basis by rearranging existing connections, with a minimum length of rearrangement sequence so that a new blocked call request can be accommodated. The proposed neural network controller uses Paull's rearrangement algorithm, along with the special (least used) switch selection rule in order to minimize the length of rearrangement sequences. The functional behavior of our model is verified by simulations and it is shown that the convergence time required for finding an optimal solution is constant, regardless of the switching network size. The performance is evaluated for random traffic with various traffic loads. Simulation results show that applying the least used switch selection rule increases the efficiency in switch rearrangements, reducing the network convergence time. The implementation aspects are also discussed to show the feasibility of the proposed approach.

ABS-SmartComAgri: An Agent-Based Simulator of Smart Communication Protocols in Wireless Sensor Networks for Debugging in Precision Agriculture.

PubMed

García-Magariño, Iván; Lacuesta, Raquel; Lloret, Jaime

2018-03-27

Smart communication protocols are becoming a key mechanism for improving communication performance in networks such as wireless sensor networks. However, the literature lacks mechanisms for simulating smart communication protocols in precision agriculture for decreasing production costs. In this context, the current work presents an agent-based simulator of smart communication protocols for efficiently managing pesticides. The simulator considers the needs of electric power, crop health, percentage of alive bugs and pesticide consumption. The current approach is illustrated with three different communication protocols respectively called (a) broadcast, (b) neighbor and (c) low-cost neighbor. The low-cost neighbor protocol obtained a statistically-significant reduction in the need of electric power over the neighbor protocol, with a very large difference according to the common interpretations about the Cohen's d effect size. The presented simulator is called ABS-SmartComAgri and is freely distributed as open-source from a public research data repository. It ensures the reproducibility of experiments and allows other researchers to extend the current approach.

ABS-SmartComAgri: An Agent-Based Simulator of Smart Communication Protocols in Wireless Sensor Networks for Debugging in Precision Agriculture

PubMed Central

2018-01-01

Smart communication protocols are becoming a key mechanism for improving communication performance in networks such as wireless sensor networks. However, the literature lacks mechanisms for simulating smart communication protocols in precision agriculture for decreasing production costs. In this context, the current work presents an agent-based simulator of smart communication protocols for efficiently managing pesticides. The simulator considers the needs of electric power, crop health, percentage of alive bugs and pesticide consumption. The current approach is illustrated with three different communication protocols respectively called (a) broadcast, (b) neighbor and (c) low-cost neighbor. The low-cost neighbor protocol obtained a statistically-significant reduction in the need of electric power over the neighbor protocol, with a very large difference according to the common interpretations about the Cohen’s d effect size. The presented simulator is called ABS-SmartComAgri and is freely distributed as open-source from a public research data repository. It ensures the reproducibility of experiments and allows other researchers to extend the current approach. PMID:29584703

Cooperative Spatial Retreat for Resilient Drone Networks †

PubMed Central

Kang, Jin-Hyeok; Kwon, Young-Min; Park, Kyung-Joon

2017-01-01

Drones are broadening their scope to various applications such as networking, package delivery, agriculture, rescue, and many more. For proper operation of drones, reliable communication should be guaranteed because drones are remotely controlled. When drones experience communication failure due to bad channel condition, interference, or jamming in a certain area, one existing solution is to exploit mobility or so-called spatial retreat to evacuate them from the communication failure area. However, the conventional spatial retreat scheme moves drones in random directions, which results in inefficient movement with significant evacuation time and waste of battery lifetime. In this paper, we propose a novel spatial retreat technique that takes advantage of cooperation between drones for resilient networking, which is called cooperative spatial retreat (CSR). Our performance evaluation shows that the proposed CSR significantly outperforms existing schemes. PMID:28467390

Mitigating Handoff Call Dropping in Wireless Cellular Networks: A Call Admission Control Technique

NASA Astrophysics Data System (ADS)

Ekpenyong, Moses Effiong; Udoh, Victoria Idia; Bassey, Udoma James

2016-06-01

Handoff management has been an important but challenging issue in the field of wireless communication. It seeks to maintain seamless connectivity of mobile users changing their points of attachment from one base station to another. This paper derives a call admission control model and establishes an optimal step-size coefficient (k) that regulates the admission probability of handoff calls. An operational CDMA network carrier was investigated through the analysis of empirical data collected over a period of 1 month, to verify the performance of the network. Our findings revealed that approximately 23 % of calls in the existing system were lost, while 40 % of the calls (on the average) were successfully admitted. A simulation of the proposed model was then carried out under ideal network conditions to study the relationship between the various network parameters and validate our claim. Simulation results showed that increasing the step-size coefficient degrades the network performance. Even at optimum step-size (k), the network could still be compromised in the presence of severe network crises, but our model was able to recover from these problems and still functions normally.

Real-Time Speaker Detection for User-Device Binding

DTIC Science & Technology

2010-12-01

31 xi THIS PAGE INTENTIONALLY LEFT BLANK xii CHAPTER 1: Introduction The roll-out of commercial wireless networks continues to rise worldwide...in a secured facility. It could also be connected to the call server via a Virtual Private Network (VPN) or public lines if security is not a top...communications network [25]. Yet, James Arden Barnett, Jr., Chief of the Public Safety and Homeland Security Bureau, argues that emergency communications

Video movie making using remote procedure calls and 4BSD Unix sockets on Unix, UNICOS, and MS-DOS systems

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

Robertson, D.W.; Johnston, W.E.; Hall, D.E.

1990-03-01

We describe the use of the Sun Remote Procedure Call and Unix socket interprocess communication mechanisms to provide the network transport for a distributed, client-server based, image handling system. Clients run under Unix or UNICOS and servers run under Unix or MS-DOS. The use of remote procedure calls across local or wide-area networks to make video movies is addressed.

Communication is the key to success in pragmatic clinical trials in Practice-based Research Networks (PBRNs).

PubMed

Bertram, Susan; Graham, Deborah; Kurland, Marge; Pace, Wilson; Madison, Suzanne; Yawn, Barbara P

2013-01-01

Effective communication is the foundation of feasibility and fidelity in practice-based pragmatic research studies. Doing a study with practices spread over several states requires long-distance communication strategies, including E-mails, faxes, telephone calls, conference calls, and texting. Compared with face-to-face communication, distance communication strategies are less familiar to most study coordinators and research teams. Developing and ensuring comfort with distance communications requires additional time and use of different talents and expertise than those required for face-to-face communication. It is necessary to make sure that messages are appropriate for the medium, clearly crafted, and presented in a manner that facilitates practices receiving and understanding the information. This discussion is based on extensive experience of 2 groups who have worked collaboratively on several large, federally funded, pragmatic trials in a practice-based research network. The goal of this article is to summarize lessons learned to facilitate the work of other research teams.

Energy star compliant voice over internet protocol (VoIP) telecommunications network including energy star compliant VoIP devices

DOEpatents

Kouchri, Farrokh Mohammadzadeh

2012-11-06

A Voice over Internet Protocol (VoIP) communications system, a method of managing a communications network in such a system and a program product therefore. The system/network includes an ENERGY STAR (E-star) aware softswitch and E-star compliant communications devices at system endpoints. The E-star aware softswitch allows E-star compliant communications devices to enter and remain in power saving mode. The E-star aware softswitch spools messages and forwards only selected messages (e.g., calls) to the devices in power saving mode. When the E-star compliant communications devices exit power saving mode, the E-star aware softswitch forwards spooled messages.

A new technique in the global reliability of cyclic communications network

NASA Technical Reports Server (NTRS)

Sjogren, Jon A.

1989-01-01

The global reliability of a communications network is the probability that given any pair of nodes, there exists a viable path between them. A characterization of connectivity, for a given class of networks, can enable one to find this reliability. Such a characterization is described for a useful class of undirected networks called daisy-chained or braided networks. This leads to a new method of quickly computing the global reliability of these networks. Asymptotic behavior in terms of component reliability is related to geometric properties of the given graph. Generalization of the technique is discussed.

A wireless medical monitoring over a heterogeneous sensor network.

PubMed

Yuce, Mehmet R; Ng, Peng Choong; Lee, Chin K; Khan, Jamil Y; Liu, Wentai

2007-01-01

This paper presents a heterogeneous sensor network system that has the capability to monitor physiological parameters from multiple patient bodies by means of different communication standards. The system uses the recently opened medical band called MICS (Medical Implant Communication Service) between the sensor nodes and a remote central control unit (CCU) that behaves as a base station. The CCU communicates with another network standard (the internet or a mobile network) for a long distance data transfer. The proposed system offers mobility to patients and flexibility to medical staff to obtain patient's physiological data on demand basis via Internet. A prototype sensor network including hardware, firmware and software designs has been implemented and tested by incorporating temperature and pulse rate sensors on nodes. The developed system has been optimized for power consumption by having the nodes sleep when there is no communication via a bidirectional communication.

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

NASA Technical Reports Server (NTRS)

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

1993-01-01

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

Design of real-time voice over internet protocol system under bandwidth network

NASA Astrophysics Data System (ADS)

Zhang, Li; Gong, Lina

2017-04-01

With the increasing bandwidth of the network and network convergence accelerating, VoIP means of communication across the network is becoming increasingly popular phenomenon. The real-time identification and analysis for VOIP flow over backbone network become the urgent needs and research hotspot of network operations management. Based on this, the paper proposes a VoIP business management system over backbone network. The system first filters VoIP data stream over backbone network and further resolves the call signaling information and media voice. The system can also be able to design appropriate rules to complete real-time reduction and presentation of specific categories of calls. Experimental results show that the system can parse and process real-time backbone of the VoIP call, and the results are presented accurately in the management interface, VoIP-based network traffic management and maintenance provide the necessary technical support.

A Very Large Area Network (VLAN) knowledge-base applied to space communication problems

NASA Technical Reports Server (NTRS)

Zander, Carol S.

1988-01-01

This paper first describes a hierarchical model for very large area networks (VLAN). Space communication problems whose solution could profit by the model are discussed and then an enhanced version of this model incorporating the knowledge needed for the missile detection-destruction problem is presented. A satellite network or VLAN is a network which includes at least one satellite. Due to the complexity, a compromise between fully centralized and fully distributed network management has been adopted. Network nodes are assigned to a physically localized group, called a partition. Partitions consist of groups of cell nodes with one cell node acting as the organizer or master, called the Group Master (GM). Coordinating the group masters is a Partition Master (PM). Knowledge is also distributed hierarchically existing in at least two nodes. Each satellite node has a back-up earth node. Knowledge must be distributed in such a way so as to minimize information loss when a node fails. Thus the model is hierarchical both physically and informationally.

Using telephony data to facilitate discovery of clinical workflows.

PubMed

Rucker, Donald W

2017-04-19

Discovery of clinical workflows to target for redesign using methods such as Lean and Six Sigma is difficult. VoIP telephone call pattern analysis may complement direct observation and EMR-based tools in understanding clinical workflows at the enterprise level by allowing visualization of institutional telecommunications activity. To build an analytic framework mapping repetitive and high-volume telephone call patterns in a large medical center to their associated clinical units using an enterprise unified communications server log file and to support visualization of specific call patterns using graphical networks. Consecutive call detail records from the medical center's unified communications server were parsed to cross-correlate telephone call patterns and map associated phone numbers to a cost center dictionary. Hashed data structures were built to allow construction of edge and node files representing high volume call patterns for display with an open source graph network tool. Summary statistics for an analysis of exactly one week's call detail records at a large academic medical center showed that 912,386 calls were placed with a total duration of 23,186 hours. Approximately half of all calling called number pairs had an average call duration under 60 seconds and of these the average call duration was 27 seconds. Cross-correlation of phone calls identified by clinical cost center can be used to generate graphical displays of clinical enterprise communications. Many calls are short. The compact data transfers within short calls may serve as automation or re-design targets. The large absolute amount of time medical center employees were engaged in VoIP telecommunications suggests that analysis of telephone call patterns may offer additional insights into core clinical workflows.

A Study of the Effects of Fieldbus Network Induced Delays on Control Systems

ERIC Educational Resources Information Center

Mainoo, Joseph

2012-01-01

Fieldbus networks are all-digital, two-way, multi-drop communication systems that are used to connect field devices such as sensors and actuators, and controllers. These fieldbus network systems are also called networked control systems (NCS). Although, there are different varieties of fieldbus networks such as Foundation Field Bus, DeviceNet, and…

FAMNET: The Use of an Electronic Mail System in Canadian Academic Family Medicine

PubMed Central

Ostbye, Truls; Needler, M.C.; Shires, David B.

1988-01-01

The major Canadian universities are connected via a computer communications network called `Netnorth'. We have used Netnorth's accessible, low-cost, electronic mail system to develop a network of academic Family Medicine users (Famnet). We then tested Famnet's utility for conducting rapid surveys. Famnet shows promise of being a useful means of undertaking regular inter-departmental communication. This system may also increase collegiality among Canadian Departments of Family Medicine and facilitate international communication in family medicine. PMID:21264023

LMSS communication network design

NASA Technical Reports Server (NTRS)

1982-01-01

The architecture of the telecommunication network as the first step in the design of the LMSS system is described. A set of functional requirements including the total number of users to be served by the LMSS are hypothesized. The design parameters are then defined at length and are systematically selected such that the resultant system is capable of serving the hypothesized number of users. The design of the backhaul link is presented. The number of multiple backhaul beams required for communication to the base stations is determined. A conceptual procedure for call-routing and locating a mobile subscriber within the LMSS network is presented. The various steps in placing a call are explained, and the relationship between the two sets of UHF and S-band multiple beams is developed. A summary of the design parameters is presented.

The impact of socio-technical communication styles on the diversity and innovation potential of global science collaboratories

DOE PAGES

Ozmen, Ozgur; Yilmaz, Levent; Smith, Jeffrey

2016-02-09

Emerging cyber-infrastructure tools are enabling scientists to transparently co-develop, share, and communicate about real-time diverse forms of knowledge artifacts. In these environments, communication preferences of scientists are posited as an important factor affecting innovation capacity and robustness of social and knowledge network structures. Scientific knowledge creation in such communities is called global participatory science (GPS). Recently, using agent-based modeling and collective action theory as a basis, a complex adaptive social communication network model (CollectiveInnoSim) is implemented. This work leverages CollectiveInnoSim implementing communication preferences of scientists. Social network metrics and knowledge production patterns are used as proxy metrics to infer innovationmore » potential of emergent knowledge and collaboration networks. The objective is to present the underlying communication dynamics of GPS in a form of computational model and delineate the impacts of various communication preferences of scientists on innovation potential of the collaboration network. Ultimately, the insight gained can help policy-makers to design GPS environments and promote innovation.« less

The impact of socio-technical communication styles on the diversity and innovation potential of global science collaboratories

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

Ozmen, Ozgur; Yilmaz, Levent; Smith, Jeffrey

Emerging cyber-infrastructure tools are enabling scientists to transparently co-develop, share, and communicate about real-time diverse forms of knowledge artifacts. In these environments, communication preferences of scientists are posited as an important factor affecting innovation capacity and robustness of social and knowledge network structures. Scientific knowledge creation in such communities is called global participatory science (GPS). Recently, using agent-based modeling and collective action theory as a basis, a complex adaptive social communication network model (CollectiveInnoSim) is implemented. This work leverages CollectiveInnoSim implementing communication preferences of scientists. Social network metrics and knowledge production patterns are used as proxy metrics to infer innovationmore » potential of emergent knowledge and collaboration networks. The objective is to present the underlying communication dynamics of GPS in a form of computational model and delineate the impacts of various communication preferences of scientists on innovation potential of the collaboration network. Ultimately, the insight gained can help policy-makers to design GPS environments and promote innovation.« less

Modeling MAC layer for powerline communications networks

NASA Astrophysics Data System (ADS)

Hrasnica, Halid; Haidine, Abdelfatteh

2001-02-01

The usage of electrical power distribution networks for voice and data transmission, called Powerline Communications, becomes nowadays more and more attractive, particularly in the telecommunication access area. The most important reasons for that are the deregulation of the telecommunication market and a fact that the access networks are still property of former monopolistic companies. In this work, first we analyze a PLC network and system structure as well as a disturbance scenario in powerline networks. After that, we define a logical structure of the powerline MAC layer and propose the reservation MAC protocols for the usage in the PLC network which provides collision free data transmission. This makes possible better network utilization and realization of QoS guarantees which can make PLC networks competitive to other access technologies.

Enhanced Communication Network Solution for Positive Train Control Implementation

NASA Technical Reports Server (NTRS)

Fatehi, M. T.; Simon, J.; Chang, W.; Chow, E. T.; Burleigh, S. C.

2011-01-01

The commuter and freight railroad industry is required to implement Positive Train Control (PTC) by 2015 (2012 for Metrolink), a challenging network communications problem. This paper will discuss present technologies developed by the National Aeronautics and Space Administration (NASA) to overcome comparable communication challenges encountered in deep space mission operations. PTC will be based on a new cellular wireless packet Internet Protocol (IP) network. However, ensuring reliability in such a network is difficult due to the "dead zones" and transient disruptions we commonly experience when we lose calls in commercial cellular networks. These disruptions make it difficult to meet PTC s stringent reliability (99.999%) and safety requirements, deployment deadlines, and budget. This paper proposes innovative solutions based on space-proven technologies that would help meet these challenges: (1) Delay Tolerant Networking (DTN) technology, designed for use in resource-constrained, embedded systems and currently in use on the International Space Station, enables reliable communication over networks in which timely data acknowledgments might not be possible due to transient link outages. (2) Policy-Based Management (PBM) provides dynamic management capabilities, allowing vital data to be exchanged selectively (with priority) by utilizing alternative communication resources. The resulting network may help railroads implement PTC faster, cheaper, and more reliably.

Massively Open Online Course for Educators (MOOC-Ed) Network Dataset

ERIC Educational Resources Information Center

Kellogg, Shaun; Edelmann, Achim

2015-01-01

This paper presents the Massively Open Online Course for Educators (MOOC-Ed) network dataset. It entails information on two online communication networks resulting from two consecutive offerings of the MOOC called "The Digital Learning Transition in K-12 Schools" in spring and fall 2013. The courses were offered to educators from the USA…

Implementation of a Framework for Collaborative Social Networks in E-Learning

ERIC Educational Resources Information Center

Maglajlic, Seid

2016-01-01

This paper describes the implementation of a framework for the construction and utilization of social networks in ELearning. These social networks aim to enhance collaboration between all E-Learning participants (i.e. both traineeto-trainee and trainee-to-tutor communication are targeted). E-Learning systems that include a so-called "social…

Dynamite Networking for Dynamite Jobs. 101 Interpersonal, Telephone and Electronic Techniques for Getting Job Leads, Interviews and Offers.

ERIC Educational Resources Information Center

Krannich, Caryl Rae; Krannich, Ronald L.

This book guides job seekers in using communication approaches that will generate useful information, advice, and referrals that lead to job interviews and offers. The book provides guidance on how to do the following: organize effective job networks; prospect for job leads; write networking letters; make cold calls; join electronic networks;…

Secure Networks for First Responders and Special Forces

NASA Technical Reports Server (NTRS)

2005-01-01

When NASA needed help better securing its communications with orbiting satellites, the Agency called on Western DataCom Co., Inc., to help develop a prototype Internet Protocol (IP) router. Westlake, Ohio-based Western DataCom designs, develops, and manufactures hardware that secures voice, video, and data transmissions over any IP-based network. The technology that it jointly developed with NASA is now serving as a communications solution in military and first-response situations.

Talking and learning physics: Predicting future grades from network measures and Force Concept Inventory pretest scores

NASA Astrophysics Data System (ADS)

Bruun, Jesper; Brewe, Eric

2013-12-01

The role of student interactions in learning situations is a foundation of sociocultural learning theory, and social network analysis can be used to quantify student relations. We discuss how self-reported student interactions can be viewed as processes of meaning making and use this to understand how quantitative measures that describe the position in a network, called centrality measures, can be understood in terms of interactions that happen in the context of a university physics course. We apply this discussion to an empirical data set of self-reported student interactions. In a weekly administered survey, first year university students enrolled in an introductory physics course at a Danish university indicated with whom they remembered having communicated within different interaction categories. For three categories pertaining to (1) communication about how to solve physics problems in the course (called the PS category), (2) communications about the nature of physics concepts (called the CD category), and (3) social interactions that are not strictly related to the content of the physics classes (called the ICS category) in the introductory mechanics course, we use the survey data to create networks of student interaction. For each of these networks, we calculate centrality measures for each student and correlate these measures with grades from the introductory course, grades from two subsequent courses, and the pretest Force Concept Inventory (FCI) scores. We find highly significant correlations (p<0.001) between network centrality measures and grades in all networks. We find the highest correlations between network centrality measures and future grades. In the network composed of interactions regarding problem solving (the PS network), the centrality measures hide and PageRank show the highest correlations (r=-0.32 and r=0.33, respectively) with future grades. In the CD network, the network measure target entropy shows the highest correlation (r=0.45) with future grades. In the network composed solely of noncontent related social interactions, these patterns of correlation are maintained in the sense that these network measures show the highest correlations and maintain their internal ranking. Using hierarchical linear regression, we find that a linear model that adds the network measures hide and target entropy, calculated on the ICS network, significantly improves a base model that uses only the FCI pretest scores from the beginning of the semester. Though one should not infer causality from these results, they do point to how social interactions in class are intertwined with academic interactions. We interpret this as an integral part of learning, and suggest that physics is a robust example.

Using Virtual Social Networks for Case Finding in Clinical Studies: An Experiment from Adolescence, Brain, Cognition, and Diabetes Study.

PubMed

Pourabbasi, Ata; Farzami, Jalal; Shirvani, Mahbubeh-Sadat Ebrahimnegad; Shams, Amir Hossein; Larijani, Bagher

2017-01-01

One of the main usages of social networks in clinical studies is facilitating the process of sampling and case finding for scientists. The main focus of this study is on comparing two different methods of sampling through phone calls and using social network, for study purposes. One of the researchers started calling 214 families of children with diabetes during 90 days. After this period, phone calls stopped, and the team started communicating with families through telegram, a virtual social network for 30 days. The number of children who participated in the study was evaluated. Although the telegram method was 60 days shorter than the phone call method, researchers found that the number of participants from telegram (17.6%) did not have any significant differences compared with the ones being phone called (12.9%). Using social networks can be suggested as a beneficial method for local researchers who look for easier sampling methods, winning their samples' trust, following up with the procedure, and an easy-access database.

A game-theoretic approach to optimize ad hoc networks inspired by small-world network topology

NASA Astrophysics Data System (ADS)

Tan, Mian; Yang, Tinghong; Chen, Xing; Yang, Gang; Zhu, Guoqing; Holme, Petter; Zhao, Jing

2018-03-01

Nodes in ad hoc networks are connected in a self-organized manner. Limited communication radius makes information transmit in multi-hop mode, and each forwarding needs to consume the energy of nodes. Insufficient communication radius or exhaustion of energy may cause the absence of some relay nodes and links, further breaking network connectivity. On the other hand, nodes in the network may refuse to cooperate due to objective faulty or personal selfish, hindering regular communication in the network. This paper proposes a model called Repeated Game in Small World Networks (RGSWN). In this model, we first construct ad hoc networks with small-world feature by forming "communication shortcuts" between multiple-radio nodes. Small characteristic path length reduces average forwarding times in networks; meanwhile high clustering coefficient enhances network robustness. Such networks still maintain relative low global power consumption, which is beneficial to extend the network survival time. Then we use MTTFT strategy (Mend-Tolerance Tit-for-Tat) for repeated game as a rule for the interactions between neighbors in the small-world networks. Compared with other five strategies of repeated game, this strategy not only punishes the nodes' selfishness more reasonably, but also has the best tolerance to the network failure. This work is insightful for designing an efficient and robust ad hoc network.

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

Welcome, Michael L.; Bell, Christian S.

GASNet (Global-Address Space Networking) is a language-independent, low-level networking layer that provides network-independent, high-performance communication primitives tailored for implementing parallel global address space SPMD languages such as UPC and Titanium. The interface is primarily intended as a compilation target and for use by runtime library writers (as opposed to end users), and the primary goals are high performance, interface portability, and expressiveness. GASNet is designed specifically to support high-performance, portable implementations of global address space languages on modern high-end communication networks. The interface provides the flexibility and extensibility required to express a wide variety of communication patterns without sacrificing performancemore » by imposing large computational overheads in the interface. The design of the GASNet interface is partitioned into two layers to maximize porting ease without sacrificing performance: the lower level is a narrow but very general interface called the GASNet core API - the design is basedheavily on Active Messages, and is implemented directly on top of each individual network architecture. The upper level is a wider and more expressive interface called GASNet extended API, which provides high-level operations such as remote memory access and various collective operations. This release implements GASNet over MPI, the Quadrics "elan" API, the Myrinet "GM" API and the "LAPI" interface to the IBM SP switch. A template is provided for adding support for additional network interfaces.« less

Ford Takes the Fast Lane to Dealer Communication and Training.

ERIC Educational Resources Information Center

Thurman, Laura

1995-01-01

Describes the Ford Motor Company's satellite-based communications network called FORDSTAR that links the home office to all dealers in the United States and Canada in order to offer training that will improve customer satisfaction. Equipment, interactivity, data transmission, and future possibilities are discussed. (LRW)

Analysis of a large-scale weighted network of one-to-one human communication

NASA Astrophysics Data System (ADS)

Onnela, Jukka-Pekka; Saramäki, Jari; Hyvönen, Jörkki; Szabó, Gábor; Argollo de Menezes, M.; Kaski, Kimmo; Barabási, Albert-László; Kertész, János

2007-06-01

We construct a connected network of 3.9 million nodes from mobile phone call records, which can be regarded as a proxy for the underlying human communication network at the societal level. We assign two weights on each edge to reflect the strength of social interaction, which are the aggregate call duration and the cumulative number of calls placed between the individuals over a period of 18 weeks. We present a detailed analysis of this weighted network by examining its degree, strength, and weight distributions, as well as its topological assortativity and weighted assortativity, clustering and weighted clustering, together with correlations between these quantities. We give an account of motif intensity and coherence distributions and compare them to a randomized reference system. We also use the concept of link overlap to measure the number of common neighbours any two adjacent nodes have, which serves as a useful local measure for identifying the interconnectedness of communities. We report a positive correlation between the overlap and weight of a link, thus providing strong quantitative evidence for the weak ties hypothesis, a central concept in social network analysis. The percolation properties of the network are found to depend on the type and order of removed links, and they can help understand how the local structure of the network manifests itself at the global level. We hope that our results will contribute to modelling weighted large-scale social networks, and believe that the systematic approach followed here can be adopted to study other weighted networks.

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

NASA Astrophysics Data System (ADS)

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

2014-08-01

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

An Architectural Concept for Intrusion Tolerance in Air Traffic Networks

NASA Technical Reports Server (NTRS)

Maddalon, Jeffrey M.; Miner, Paul S.

2003-01-01

The goal of an intrusion tolerant network is to continue to provide predictable and reliable communication in the presence of a limited num ber of compromised network components. The behavior of a compromised network component ranges from a node that no longer responds to a nod e that is under the control of a malicious entity that is actively tr ying to cause other nodes to fail. Most current data communication ne tworks do not include support for tolerating unconstrained misbehavio r of components in the network. However, the fault tolerance communit y has developed protocols that provide both predictable and reliable communication in the presence of the worst possible behavior of a limited number of nodes in the system. One may view a malicious entity in a communication network as a node that has failed and is behaving in an arbitrary manner. NASA/Langley Research Center has developed one such fault-tolerant computing platform called SPIDER (Scalable Proces sor-Independent Design for Electromagnetic Resilience). The protocols and interconnection mechanisms of SPIDER may be adapted to large-sca le, distributed communication networks such as would be required for future Air Traffic Management systems. The predictability and reliabi lity guarantees provided by the SPIDER protocols have been formally v erified. This analysis can be readily adapted to similar network stru ctures.

The Tracking & Data Relay Satellite System. The New Space Network.

ERIC Educational Resources Information Center

Froehlich, Walter

This publication describes the giant-capacity space communications installation called the "Tracking and Data Relay Satellite System" (TDRSS). Chapters include: (1) "A New Communications Bridge to Orbit" (illustrating what it is and how it looks); (2) "TDRSS Goes to Work" (describing how it functions); (3) "The…

47 CFR 64.601 - Definitions and provisions of general applicability.

Code of Federal Regulations, 2014 CFR

2014-10-01

... a text telephone (TTY) and the public switched telephone network. (18) IP Relay access technology... used to make and receive an Internet-based TRS call. (20) Neutral Video Communication Service Platform... by the Neutral Video Communication Service Platform include the provision of a video link, user...

47 CFR 64.601 - Definitions and provisions of general applicability.

Code of Federal Regulations, 2013 CFR

2013-10-01

... a text telephone (TTY) and the public switched telephone network. (18) IP Relay access technology... used to make and receive an Internet-based TRS call. (20) Neutral Video Communication Service Platform... by the Neutral Video Communication Service Platform include the provision of a video link, user...

An inter-networking mechanism with stepwise synchronization for wireless sensor networks.

PubMed

Yamamoto, Hiroshi; Wakamiya, Naoki; Murata, Masayuki

2011-01-01

To realize the ambient information society, multiple wireless networks deployed in the region and devices carried by users are required to cooperate with each other. Since duty cycles and operational frequencies are different among networks, we need a mechanism to allow networks to efficiently exchange messages. For this purpose, we propose a novel inter-networking mechanism where two networks are synchronized with each other in a moderate manner, which we call stepwise synchronization. With our proposal, to bridge the gap between intrinsic operational frequencies, nodes near the border of networks adjust their operational frequencies in a stepwise fashion based on the pulse-coupled oscillator model as a fundamental theory of synchronization. Through simulation experiments, we show that the communication delay and the energy consumption of border nodes are reduced, which enables wireless sensor networks to communicate longer with each other.

A Novel Dual Separate Paths (DSP) Algorithm Providing Fault-Tolerant Communication for Wireless Sensor Networks.

PubMed

Tien, Nguyen Xuan; Kim, Semog; Rhee, Jong Myung; Park, Sang Yoon

2017-07-25

Fault tolerance has long been a major concern for sensor communications in fault-tolerant cyber physical systems (CPSs). Network failure problems often occur in wireless sensor networks (WSNs) due to various factors such as the insufficient power of sensor nodes, the dislocation of sensor nodes, the unstable state of wireless links, and unpredictable environmental interference. Fault tolerance is thus one of the key requirements for data communications in WSN applications. This paper proposes a novel path redundancy-based algorithm, called dual separate paths (DSP), that provides fault-tolerant communication with the improvement of the network traffic performance for WSN applications, such as fault-tolerant CPSs. The proposed DSP algorithm establishes two separate paths between a source and a destination in a network based on the network topology information. These paths are node-disjoint paths and have optimal path distances. Unicast frames are delivered from the source to the destination in the network through the dual paths, providing fault-tolerant communication and reducing redundant unicast traffic for the network. The DSP algorithm can be applied to wired and wireless networks, such as WSNs, to provide seamless fault-tolerant communication for mission-critical and life-critical applications such as fault-tolerant CPSs. The analyzed and simulated results show that the DSP-based approach not only provides fault-tolerant communication, but also improves network traffic performance. For the case study in this paper, when the DSP algorithm was applied to high-availability seamless redundancy (HSR) networks, the proposed DSP-based approach reduced the network traffic by 80% to 88% compared with the standard HSR protocol, thus improving network traffic performance.

Topology control algorithm for wireless sensor networks based on Link forwarding

NASA Astrophysics Data System (ADS)

Pucuo, Cairen; Qi, Ai-qin

2018-03-01

The research of topology control could effectively save energy and increase the service life of network based on wireless sensor. In this paper, a arithmetic called LTHC (link transmit hybrid clustering) based on link transmit is proposed. It decreases expenditure of energy by changing the way of cluster-node’s communication. The idea is to establish a link between cluster and SINK node when the cluster is formed, and link-node must be non-cluster. Through the link, cluster sends information to SINK nodes. For the sake of achieving the uniform distribution of energy on the network, prolongate the network survival time, and improve the purpose of communication, the communication will cut down much more expenditure of energy for cluster which away from SINK node. In the two aspects of improving the traffic and network survival time, we find that the LTCH is far superior to the traditional LEACH by experiments.

Self-organized Anonymous Authentication in Mobile Ad Hoc Networks

NASA Astrophysics Data System (ADS)

Freudiger, Julien; Raya, Maxim; Hubaux, Jean-Pierre

Pervasive communications bring along new privacy challenges, fueled by the capability of mobile devices to communicate with, and thus “sniff on”, each other directly. We design a new mechanism that aims at achieving location privacy in these forthcoming mobile networks, whereby mobile nodes collect the pseudonyms of the nodes they encounter to generate their own privacy cloaks. Thus, privacy emerges from the mobile network and users gain control over the disclosure of their locations. We call this new paradigm self-organized location privacy. In this work, we focus on the problem of self-organized anonymous authentication that is a necessary prerequisite for location privacy. We investigate, using graph theory, the optimality of different cloak constructions and evaluate with simulations the achievable anonymity in various network topologies. We show that peer-to-peer wireless communications and mobility help in the establishment of self-organized anonymous authentication in mobile networks.

Critical size of ego communication networks

NASA Astrophysics Data System (ADS)

Wang, Qing; Gao, Jian; Zhou, Tao; Hu, Zheng; Tian, Hui

2016-06-01

With the help of information and communication technologies, studies on the overall social networks have been extensively reported recently. However, investigations on the directed Ego Communication Networks (ECNs) remain insufficient, where an ECN stands for a sub network composed of a centralized individual and his/her direct contacts. In this paper, the directed ECNs are built on the Call Detail Records (CDRs), which cover more than 7 million people of a provincial capital city in China for half a year. Results show that there is a critical size for ECN at about 150, above which the average emotional closeness between ego and alters drops, the balanced relationship between ego and network collapses, and the proportion of strong ties decreases. This paper not only demonstrate the significance of ECN size in affecting its properties, but also shows accordance with the “Dunbar's Number”. These results can be viewed as a cross-culture supportive evidence to the well-known Social Brain Hypothesis (SBH).

The Deep Impact Network Experiment Operations Center

NASA Technical Reports Server (NTRS)

Torgerson, J. Leigh; Clare, Loren; Wang, Shin-Ywan

2009-01-01

Delay/Disruption Tolerant Networking (DTN) promises solutions in solving space communications challenges arising from disconnections as orbiters lose line-of-sight with landers, long propagation delays over interplanetary links, and other phenomena. DTN has been identified as the basis for the future NASA space communications network backbone, and international standardization is progressing through both the Consultative Committee for Space Data Systems (CCSDS) and the Internet Engineering Task Force (IETF). JPL has developed an implementation of the DTN architecture, called the Interplanetary Overlay Network (ION). ION is specifically implemented for space use, including design for use in a real-time operating system environment and high processing efficiency. In order to raise the Technology Readiness Level of ION, the first deep space flight demonstration of DTN is underway, using the Deep Impact (DI) spacecraft. Called the Deep Impact Network (DINET), operations are planned for Fall 2008. An essential component of the DINET project is the Experiment Operations Center (EOC), which will generate and receive the test communications traffic as well as "out-of-DTN band" command and control of the DTN experiment, store DTN flight test information in a database, provide display systems for monitoring DTN operations status and statistics (e.g., bundle throughput), and support query and analyses of the data collected. This paper describes the DINET EOC and its value in the DTN flight experiment and potential for further DTN testing.

An Inter-Networking Mechanism with Stepwise Synchronization for Wireless Sensor Networks

PubMed Central

Yamamoto, Hiroshi; Wakamiya, Naoki; Murata, Masayuki

2011-01-01

To realize the ambient information society, multiple wireless networks deployed in the region and devices carried by users are required to cooperate with each other. Since duty cycles and operational frequencies are different among networks, we need a mechanism to allow networks to efficiently exchange messages. For this purpose, we propose a novel inter-networking mechanism where two networks are synchronized with each other in a moderate manner, which we call stepwise synchronization. With our proposal, to bridge the gap between intrinsic operational frequencies, nodes near the border of networks adjust their operational frequencies in a stepwise fashion based on the pulse-coupled oscillator model as a fundamental theory of synchronization. Through simulation experiments, we show that the communication delay and the energy consumption of border nodes are reduced, which enables wireless sensor networks to communicate longer with each other. PMID:22164073

How women organize social networks different from men

PubMed Central

Szell, Michael; Thurner, Stefan

2013-01-01

Superpositions of social networks, such as communication, friendship, or trade networks, are called multiplex networks, forming the structural backbone of human societies. Novel datasets now allow quantification and exploration of multiplex networks. Here we study gender-specific differences of a multiplex network from a complete behavioral dataset of an online-game society of about 300,000 players. On the individual level females perform better economically and are less risk-taking than males. Males reciprocate friendship requests from females faster than vice versa and hesitate to reciprocate hostile actions of females. On the network level females have more communication partners, who are less connected than partners of males. We find a strong homophily effect for females and higher clustering coefficients of females in trade and attack networks. Cooperative links between males are under-represented, reflecting competition for resources among males. These results confirm quantitatively that females and males manage their social networks in substantially different ways. PMID:23393616

How women organize social networks different from men.

PubMed

Szell, Michael; Thurner, Stefan

2013-01-01

Superpositions of social networks, such as communication, friendship, or trade networks, are called multiplex networks, forming the structural backbone of human societies. Novel datasets now allow quantification and exploration of multiplex networks. Here we study gender-specific differences of a multiplex network from a complete behavioral dataset of an online-game society of about 300,000 players. On the individual level females perform better economically and are less risk-taking than males. Males reciprocate friendship requests from females faster than vice versa and hesitate to reciprocate hostile actions of females. On the network level females have more communication partners, who are less connected than partners of males. We find a strong homophily effect for females and higher clustering coefficients of females in trade and attack networks. Cooperative links between males are under-represented, reflecting competition for resources among males. These results confirm quantitatively that females and males manage their social networks in substantially different ways.

Impact of network structure on the capacity of wireless multihop ad hoc communication

NASA Astrophysics Data System (ADS)

Krause, Wolfram; Glauche, Ingmar; Sollacher, Rudolf; Greiner, Martin

2004-07-01

As a representative of a complex technological system, the so-called wireless multihop ad hoc communication networks are discussed. They represent an infrastructure-less generalization of todays wireless cellular phone networks. Lacking a central control authority, the ad hoc nodes have to coordinate themselves such that the overall network performs in an optimal way. A performance indicator is the end-to-end throughput capacity. Various models, generating differing ad hoc network structure via differing transmission power assignments, are constructed and characterized. They serve as input for a generic data traffic simulation as well as some semi-analytic estimations. The latter reveal that due to the most-critical-node effect the end-to-end throughput capacity sensitively depends on the underlying network structure, resulting in differing scaling laws with respect to network size.

Error and attack tolerance of complex networks

NASA Astrophysics Data System (ADS)

Albert, Réka; Jeong, Hawoong; Barabási, Albert-László

2000-07-01

Many complex systems display a surprising degree of tolerance against errors. For example, relatively simple organisms grow, persist and reproduce despite drastic pharmaceutical or environmental interventions, an error tolerance attributed to the robustness of the underlying metabolic network. Complex communication networks display a surprising degree of robustness: although key components regularly malfunction, local failures rarely lead to the loss of the global information-carrying ability of the network. The stability of these and other complex systems is often attributed to the redundant wiring of the functional web defined by the systems' components. Here we demonstrate that error tolerance is not shared by all redundant systems: it is displayed only by a class of inhomogeneously wired networks, called scale-free networks, which include the World-Wide Web, the Internet, social networks and cells. We find that such networks display an unexpected degree of robustness, the ability of their nodes to communicate being unaffected even by unrealistically high failure rates. However, error tolerance comes at a high price in that these networks are extremely vulnerable to attacks (that is, to the selection and removal of a few nodes that play a vital role in maintaining the network's connectivity). Such error tolerance and attack vulnerability are generic properties of communication networks.

Airborne wireless communication systems, airborne communication methods, and communication methods

DOEpatents

Deaton, Juan D [Menan, ID; Schmitt, Michael J [Idaho Falls, ID; Jones, Warren F [Idaho Falls, ID

2011-12-13

An airborne wireless communication system includes circuitry configured to access information describing a configuration of a terrestrial wireless communication base station that has become disabled. The terrestrial base station is configured to implement wireless communication between wireless devices located within a geographical area and a network when the terrestrial base station is not disabled. The circuitry is further configured, based on the information, to configure the airborne station to have the configuration of the terrestrial base station. An airborne communication method includes answering a 911 call from a terrestrial cellular wireless phone using an airborne wireless communication system.

Aeronautical Satellite-Assisted Process for Information Exchange Through Network Technologies (Aero-SAPIENT) Conducted

NASA Technical Reports Server (NTRS)

Zernic, Michael J.

2002-01-01

Broadband satellite communications for aeronautics marries communication and network technologies to address NASA's goals in information technology base research and development, thereby serving the safety and capacity needs of the National Airspace System. This marriage of technology increases the interactivity between airborne vehicles and ground systems. It improves decision-making and efficiency, reduces operation costs, and improves the safety and capacity of the National Airspace System. To this end, a collaborative project called the Aeronautical Satellite Assisted Process for Information Exchange through Network Technologies, or Aero-SAPIENT, was conducted out of Tinker AFB, Oklahoma, during November and December 2000.

ACTS TDMA network control. [Advanced Communication Technology Satellite

NASA Technical Reports Server (NTRS)

Inukai, T.; Campanella, S. J.

1984-01-01

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

Probabilistic Priority Message Checking Modeling Based on Controller Area Networks

NASA Astrophysics Data System (ADS)

Lin, Cheng-Min

Although the probabilistic model checking tool called PRISM has been applied in many communication systems, such as wireless local area network, Bluetooth, and ZigBee, the technique is not used in a controller area network (CAN). In this paper, we use PRISM to model the mechanism of priority messages for CAN because the mechanism has allowed CAN to become the leader in serial communication for automobile and industry control. Through modeling CAN, it is easy to analyze the characteristic of CAN for further improving the security and efficiency of automobiles. The Markov chain model helps us to model the behaviour of priority messages.

Two-dimensional quantum repeaters

NASA Astrophysics Data System (ADS)

Wallnöfer, J.; Zwerger, M.; Muschik, C.; Sangouard, N.; Dür, W.

2016-11-01

The endeavor to develop quantum networks gave rise to a rapidly developing field with far-reaching applications such as secure communication and the realization of distributed computing tasks. This ultimately calls for the creation of flexible multiuser structures that allow for quantum communication between arbitrary pairs of parties in the network and facilitate also multiuser applications. To address this challenge, we propose a two-dimensional quantum repeater architecture to establish long-distance entanglement shared between multiple communication partners in the presence of channel noise and imperfect local control operations. The scheme is based on the creation of self-similar multiqubit entanglement structures at growing scale, where variants of entanglement swapping and multiparty entanglement purification are combined to create high-fidelity entangled states. We show how such networks can be implemented using trapped ions in cavities.

From seconds to months: an overview of multi-scale dynamics of mobile telephone calls

NASA Astrophysics Data System (ADS)

Saramäki, Jari; Moro, Esteban

2015-06-01

Big Data on electronic records of social interactions allow approaching human behaviour and sociality from a quantitative point of view with unforeseen statistical power. Mobile telephone Call Detail Records (CDRs), automatically collected by telecom operators for billing purposes, have proven especially fruitful for understanding one-to-one communication patterns as well as the dynamics of social networks that are reflected in such patterns. We present an overview of empirical results on the multi-scale dynamics of social dynamics and networks inferred from mobile telephone calls. We begin with the shortest timescales and fastest dynamics, such as burstiness of call sequences between individuals, and "zoom out" towards longer temporal and larger structural scales, from temporal motifs formed by correlated calls between multiple individuals to long-term dynamics of social groups. We conclude this overview with a future outlook.

Output power distributions of terminals in a 3G mobile communication network.

PubMed

Persson, Tomas; Törnevik, Christer; Larsson, Lars-Eric; Lovén, Jan

2012-05-01

The objective of this study was to examine the distribution of the output power of mobile phones and other terminals connected to a 3G network in Sweden. It is well known that 3G terminals can operate with very low output power, particularly for voice calls. Measurements of terminal output power were conducted in the Swedish TeliaSonera 3G network in November 2008 by recording network statistics. In the analysis, discrimination was made between rural, suburban, urban, and dedicated indoor networks. In addition, information about terminal output power was possible to collect separately for voice and data traffic. Information from six different Radio Network Controllers (RNCs) was collected during at least 1 week. In total, more than 800000 h of voice calls were collected and in addition to that a substantial amount of data traffic. The average terminal output power for 3G voice calls was below 1 mW for any environment including rural, urban, and dedicated indoor networks. This is <1% of the maximum available output power. For data applications the average output power was about 6-8 dB higher than for voice calls. For rural areas the output power was about 2 dB higher, on average, than in urban areas. Copyright © 2011 Wiley Periodicals, Inc.

Developing a global aeronautical satellite system

NASA Technical Reports Server (NTRS)

Dement, Donald K.

1988-01-01

Arinc, an airline industry-owned and operated company in the United States, has taken steps toward establishing a global aeronautical satellite communications system. Plans call for initiation of a thin-route data operation in 1989, upgrading to establish voice communications via shared spot-beam transponders carried on other satellites, and deploying a worldwide network using dedicated satellites by 1994.

An iteration algorithm for optimal network flows

NASA Astrophysics Data System (ADS)

Woong, C. J.

1983-09-01

A packet switching network has the desirable feature of rapidly handling short (bursty) messages of the type often found in computer communication systems. In evaluating packet switching networks, the average time delay per packet is one of the most important measures of performance. The problem of message routing to minimize time delay is analyzed here using two approaches, called "successive saturation' and "max-slack', for various traffic requirement matrices and networks with fixed topology and link capacities.

Development of a demand assignment/TDMA system for international business satellite communications

NASA Astrophysics Data System (ADS)

Nohara, Mitsuo; Takeuchi, Yoshio; Takahata, Fumio; Hirata, Yasuo; Yamazaki, Yoshiharu

An experimental IBS (international business satellite) communications system based on a demand assignment and TDMA (time-division multiple-access) operation has been developed. The system utilizes a limited satellite resource efficiently and provides various kinds of ISDN services totally. A discussion is presented of the IBS network configurations suitable to international communications and describes the developed communications system from the viewpoint of the hardware and software implementation. The performance in terms of the transmission quality and call processing is also demonstrated.

A time reference distribution concept for a time division communication network

NASA Technical Reports Server (NTRS)

Stover, H. A.

1973-01-01

Starting with an assumed ideal network having perfect clocks at every node and known fixed transmission delays between nodes, the effects of adding tolerances to both transmission delays and nodal clocks is described. The advantages of controlling tolerances on time rather than frequency are discussed. Then a concept is presented for maintaining these tolerances on time throughout the network. This concept, called time reference distribution, is a systematic technique for distributing time reference to all nodes of the network. It is reliable, survivable and possesses many other desirable characteristics. Some of its features such as an excellent self monitoring capability will be pointed out. Some preliminary estimates of the accuracy that might be expected are developed and there is a brief discussion of the impact upon communication system costs. Time reference distribution is a concept that appears very attractive. It has not had experimental evaluation and has not yet been endorsed for use in any communication network.

Design and evaluation of Nemesis, a scalable, low-latency, message-passing communication subsystem.

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

Buntinas, D.; Mercier, G.; Gropp, W.

2005-12-02

This paper presents a new low-level communication subsystem called Nemesis. Nemesis has been designed and implemented to be scalable and efficient both in the intranode communication context using shared-memory and in the internode communication case using high-performance networks and is natively multimethod-enabled. Nemesis has been integrated in MPICH2 as a CH3 channel and delivers better performance than other dedicated communication channels in MPICH2. Furthermore, the resulting MPICH2 architecture outperforms other MPI implementations in point-to-point benchmarks.

Smart Grid Communications System Blueprint

NASA Astrophysics Data System (ADS)

Clark, Adrian; Pavlovski, Chris

2010-10-01

Telecommunications operators are well versed in deploying 2G and 3G wireless networks. These networks presently support the mobile business user and/or retail consumer wishing to place conventional voice calls and data connections. The electrical power industry has recently commenced transformation of its distribution networks by deploying smart monitoring and control devices throughout their networks. This evolution of the network into a `smart grid' has also motivated the need to deploy wireless technologies that bridge the communication gap between the smart devices and information technology systems. The requirements of these networks differ from traditional wireless networks that communications operators have deployed, which have thus far forced energy companies to consider deploying their own wireless networks. We present our experience in deploying wireless networks to support the smart grid and highlight the key properties of these networks. These characteristics include application awareness, support for large numbers of simultaneous cell connections, high service coverage and prioritized routing of data. We also outline our target blueprint architecture that may be useful to the industry in building wireless and fixed networks to support the smart grid. By observing our experiences, telecommunications operators and equipment manufacturers will be able to augment their current networks and products in a way that accommodates the needs of the emerging industry of smart grids and intelligent electrical networks.

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

NASA Astrophysics Data System (ADS)

Görbil, Gökçe; Gelenbe, Erol

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

Vocalization frequency and duration are coded in separate hindbrain nuclei.

PubMed

Chagnaud, Boris P; Baker, Robert; Bass, Andrew H

2011-06-14

Temporal patterning is an essential feature of neural networks producing precisely timed behaviours such as vocalizations that are widely used in vertebrate social communication. Here we show that intrinsic and network properties of separate hindbrain neuronal populations encode the natural call attributes of frequency and duration in vocal fish. Intracellular structure/function analyses indicate that call duration is encoded by a sustained membrane depolarization in vocal prepacemaker neurons that innervate downstream pacemaker neurons. Pacemaker neurons, in turn, encode call frequency by rhythmic, ultrafast oscillations in their membrane potential. Pharmacological manipulations show prepacemaker activity to be independent of pacemaker function, thus accounting for natural variation in duration which is the predominant feature distinguishing call types. Prepacemaker neurons also innervate key hindbrain auditory nuclei thereby effectively serving as a call-duration corollary discharge. We propose that premotor compartmentalization of neurons coding distinct acoustic attributes is a fundamental trait of hindbrain vocal pattern generators among vertebrates.

Vocalization frequency and duration are coded in separate hindbrain nuclei

PubMed Central

Chagnaud, Boris P.; Baker, Robert; Bass, Andrew H.

2011-01-01

Temporal patterning is an essential feature of neural networks producing precisely timed behaviours such as vocalizations that are widely used in vertebrate social communication. Here we show that intrinsic and network properties of separate hindbrain neuronal populations encode the natural call attributes of frequency and duration in vocal fish. Intracellular structure/function analyses indicate that call duration is encoded by a sustained membrane depolarization in vocal prepacemaker neurons that innervate downstream pacemaker neurons. Pacemaker neurons, in turn, encode call frequency by rhythmic, ultrafast oscillations in their membrane potential. Pharmacological manipulations show prepacemaker activity to be independent of pacemaker function, thus accounting for natural variation in duration which is the predominant feature distinguishing call types. Prepacemaker neurons also innervate key hindbrain auditory nuclei thereby effectively serving as a call-duration corollary discharge. We propose that premotor compartmentalization of neurons coding distinct acoustic attributes is a fundamental trait of hindbrain vocal pattern generators among vertebrates. PMID:21673667

Large Scale Data Analysis and Knowledge Extraction in Communication Data

DTIC Science & Technology

2017-03-31

this purpose, we developed a novel method the " Correlation Density Ran!C’ which finds probability density distribution of related frequent event on all...which is called " Correlation Density Rank", is developed to derive the community tree from the network. As in the real world, where a network is...Community Structure in Dynamic Social Networks using the Correlation Density Rank," 2014 ASE BigData/SocialCom/Cybersecurity Conference, Stanford

Quantifying socio-economic indicators in developing countries from mobile phone communication data: applications to Côte d’Ivoire

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

Mao, Huina; Shuai, Xin; Ahn, Yong -Yeol

The widespread adoption of mobile devices that record the communications, social relations, and movements of billions of individuals in great detail presents unique opportunities for the study of social structures and human dynamics at very large scales. This is particularly the case for developing countries where social and economic data can be hard to obtain and is often too sparse for real-time analytics. In this paper, we leverage mobile call log data from Côte d’Ivoire to analyze the relations between its nation-wide communications network and the socio-economic dynamics of its regional economies. We introduce the CallRank indicator to quantify themore » relative importance of an area on the basis of call records, and show that a region’s ratio of in- and out-going calls can predict its income level. We detect a communication divide between rich and poor regions of Côte d’Ivoire, which corresponds to existing socio-economic data. Our results demonstrate the potential of mobile communication data to monitor the economic development and social dynamics of low-income developing countries in the absence of extensive econometric and social data. Finally, our work may support efforts to stimulate sustainable economic development and to reduce poverty and inequality.« less

Quantifying socio-economic indicators in developing countries from mobile phone communication data: applications to Côte d’Ivoire

DOE PAGES

Mao, Huina; Shuai, Xin; Ahn, Yong -Yeol; ...

2015-10-13

The widespread adoption of mobile devices that record the communications, social relations, and movements of billions of individuals in great detail presents unique opportunities for the study of social structures and human dynamics at very large scales. This is particularly the case for developing countries where social and economic data can be hard to obtain and is often too sparse for real-time analytics. In this paper, we leverage mobile call log data from Côte d’Ivoire to analyze the relations between its nation-wide communications network and the socio-economic dynamics of its regional economies. We introduce the CallRank indicator to quantify themore » relative importance of an area on the basis of call records, and show that a region’s ratio of in- and out-going calls can predict its income level. We detect a communication divide between rich and poor regions of Côte d’Ivoire, which corresponds to existing socio-economic data. Our results demonstrate the potential of mobile communication data to monitor the economic development and social dynamics of low-income developing countries in the absence of extensive econometric and social data. Finally, our work may support efforts to stimulate sustainable economic development and to reduce poverty and inequality.« less

Degraded Operational Environment: Integration of Social Network Infrastructure Concept in a Traditional Military C2 System

DTIC Science & Technology

2013-06-01

Communication Applet) UNIGE – D.I.M.E. Using a free application as “MIT APP Inventor” Android Software Development Kit DEGRADED C2 ICCRTS 2013...operate on an Android operating system up-gradable on which will be developed a simplified ACA ( Android Communication Applet) that will call C24U...Server) IP number . . . Portable COTS Devices ACA - C24U ( Android Communication Applet) Sending/receiving SEFL (Simple Exchange

Integrated Network Architecture for NASA's Orion Missions

NASA Technical Reports Server (NTRS)

Bhasin, Kul B.; Hayden, Jeffrey L.; Sartwell, Thomas; Miller, Ronald A.; Hudiburg, John J.

2008-01-01

NASA is planning a series of short and long duration human and robotic missions to explore the Moon and then Mars. The series of missions will begin with a new crew exploration vehicle (called Orion) that will initially provide crew exchange and cargo supply support to the International Space Station (ISS) and then become a human conveyance for travel to the Moon. The Orion vehicle will be mounted atop the Ares I launch vehicle for a series of pre-launch tests and then launched and inserted into low Earth orbit (LEO) for crew exchange missions to the ISS. The Orion and Ares I comprise the initial vehicles in the Constellation system of systems that later includes Ares V, Earth departure stage, lunar lander, and other lunar surface systems for the lunar exploration missions. These key systems will enable the lunar surface exploration missions to be initiated in 2018. The complexity of the Constellation system of systems and missions will require a communication and navigation infrastructure to provide low and high rate forward and return communication services, tracking services, and ground network services. The infrastructure must provide robust, reliable, safe, sustainable, and autonomous operations at minimum cost while maximizing the exploration capabilities and science return. The infrastructure will be based on a network of networks architecture that will integrate NASA legacy communication, modified elements, and navigation systems. New networks will be added to extend communication, navigation, and timing services for the Moon missions. Internet protocol (IP) and network management systems within the networks will enable interoperability throughout the Constellation system of systems. An integrated network architecture has developed based on the emerging Constellation requirements for Orion missions. The architecture, as presented in this paper, addresses the early Orion missions to the ISS with communication, navigation, and network services over five phases of a mission: pre-launch, launch from T0 to T+6.5 min, launch from T+6.5 min to 12 min, in LEO for rendezvous and docking with ISS, and return to Earth. The network of networks that supports the mission during each of these phases and the concepts of operations during those phases are developed as a high level operational concepts graphic called OV-1, an architecture diagram type described in the Department of Defense Architecture Framework (DoDAF). Additional operational views on organizational relationships (OV-4), operational activities (OV-5), and operational node connectivity (OV-2) are also discussed. The system interfaces view (SV-1) that provides the communication and navigation services to Orion is also included and described. The challenges of architecting integrated network architecture for the NASA Orion missions are highlighted.

Internet Passport: NorthWestNet's Guide to Our World Online. Fourth Edition.

ERIC Educational Resources Information Center

Kochmer, Jonathan

The purpose of this guide is to help computer network users get over the hurdle of new technologies. Every Internet user is different, but most network activities depend on the mastery of three basic skills: using electronic mail (e-mail) to communicate with other Internet users; logging in to remote computers with a service called Telnet, and…

Decentralized System Control.

DTIC Science & Technology

1986-04-01

a Local Area Network Environment. Submitted for Publication. 1982. [Barrnger 791 Barringer . H,. P. C. Capon, and R . Phillips. The Portable Compiling...configuration and hardware. [Chesley 81 Chesley, Harry R . and Bruce V. Hunt., % Squire - A Communications-Oriented Operating System. Computer Networks 5(2...copying the information. Transfers between machines and copying " - r pages as necemry. [Nelson 80] Nelson, Bruce Jay. Remote Procedure Call. PhD Thesis

The Use of an Educational Social Networking Site for English Language Learning beyond the Classroom in a Japanese University Setting

ERIC Educational Resources Information Center

Okumura, Shinji

2016-01-01

This study describes an attempt of using an educational social networking platform, which is called Edmodo, for English language learning outside classrooms at tertiary level. Considering the notion of communicative competence, the instructor incorporated Edmodo into his English classes as a project which is a formal assignment. In the project,…

Data on the key performance indicators for quality of service of GSM networks in Nigeria.

PubMed

Popoola, Segun I; Atayero, Aderemi A; Faruk, Nasir; Badejo, Joke A

2018-02-01

In this data article, the Key Performance Indicators (KPIs) for Quality of Service (QoS) of Global System for Mobile Communications (GSM) networks in Nigeria are provided and analyzed. The data provided in this paper contain the Call Setup Success Rate (CSSR), Drop Call Rate (DCR), Stand-alone Dedicated Channel (SDCCH) congestion, and Traffic Channel (TCH) congestion for the four GSM network operators in Nigeria (Airtel, Etisalat, Glo, and MTN). These comprehensive data were obtained from the Nigerian Communications Commission (NCC). Significant differences in each of the KPIs for the four quarters of each year were presented based on Analysis of Variance (ANOVA). The values of the KPIs were plotted against the months of the year for better visualization and understanding of data trends across the four quarters. Multiple comparisons of the mean-quarterly differences of the KPIs were also presented using Tukey's Post Hoc test. Public availability and further interpretation and discussion of these useful information will assist the network providers, Nigerian government, local and international regulatory bodies, policy makers, and other stakeholders in ensuring access of people, machines, and things to high quality telecommunications services.

Mobile phones and social structures: an exploration of a closed user group in rural Ghana

PubMed Central

2013-01-01

Background In the Millennium Villages Project site of Bonsaaso, Ghana, the Health Team is using a mobile phone closed user group to place calls amongst one another at no cost. Methods In order to determine the utilization and acceptability of the closed user group amongst users, social network analysis and qualitative methods were used. Key informants were identified and interviewed. The key informants also kept prospective call journals. Billing statements and de-identified call data from the closed user group were used to generate data for analyzing the social structure revealed by the network traffic. Results The majority of communication within the closed user group was personal and not for professional purposes. The members of the CUG felt that the group improved their efficiency at work. Conclusions The methods used present an interesting way to investigate the social structure surrounding communication via mobile phones. In addition, the benefits identified from the exploration of this closed user group make a case for supporting mobile phone closed user groups amongst professional groups. PMID:24007331

Land mobile satellite system requirements

NASA Astrophysics Data System (ADS)

Kiesling, J. D.

1983-05-01

A Land Mobile Satellite System (LMSS) provides voice, data and related communications services to moving vehicles and persons. Communications between the mobiles and satellite are in the 806-890 MHz band. The satellite translates these signals to a ""fixed services band'' such as 14/12 GHz band (Ku-band), and communicates in this band with fixed terminals called gateways. The gateways are located at convenient places such as telephone switches (which provide entry into the national telephone system), dispatcher headquarters, computer centers, etc. Communications are therefore principally mobile to fixed. A third communications link, also at Ku-band, is needed between the satellite and a single fixed ground station. This link provides satellite command, telemetry and ranging and also provides a network control function. The latter, through a common signalling system, receives requests and assigns channel slots, and otherwise controls, monitors and polices the network and collects billing information.

Land mobile satellite system requirements

NASA Technical Reports Server (NTRS)

Kiesling, J. D.

1983-01-01

A Land Mobile Satellite System (LMSS) provides voice, data and related communications services to moving vehicles and persons. Communications between the mobiles and satellite are in the 806-890 MHz band. The satellite translates these signals to a ""fixed services band'' such as 14/12 GHz band (Ku-band), and communicates in this band with fixed terminals called gateways. The gateways are located at convenient places such as telephone switches (which provide entry into the national telephone system), dispatcher headquarters, computer centers, etc. Communications are therefore principally mobile to fixed. A third communications link, also at Ku-band, is needed between the satellite and a single fixed ground station. This link provides satellite command, telemetry and ranging and also provides a network control function. The latter, through a common signalling system, receives requests and assigns channel slots, and otherwise controls, monitors and polices the network and collects billing information.

Transparent Ada rendezvous in a fault tolerant distributed system

NASA Technical Reports Server (NTRS)

Racine, Roger

1986-01-01

There are many problems associated with distributing an Ada program over a loosely coupled communication network. Some of these problems involve the various aspects of the distributed rendezvous. The problems addressed involve supporting the delay statement in a selective call and supporting the else clause in a selective call. Most of these difficulties are compounded by the need for an efficient communication system. The difficulties are compounded even more by considering the possibility of hardware faults occurring while the program is running. With a hardware fault tolerant computer system, it is possible to design a distribution scheme and communication software which is efficient and allows Ada semantics to be preserved. An Ada design for the communications software of one such system will be presented, including a description of the services provided in the seven layers of an International Standards Organization (ISO) Open System Interconnect (OSI) model communications system. The system capabilities (hardware and software) that allow this communication system will also be described.

MSAT and cellular hybrid networking

NASA Astrophysics Data System (ADS)

Baranowsky, Patrick W., II

Westinghouse Electric Corporation is developing both the Communications Ground Segment and the Series 1000 Mobile Phone for American Mobile Satellite Corporation's (AMSC's) Mobile Satellite (MSAT) system. The success of the voice services portion of this system depends, to some extent, upon the interoperability of the cellular network and the satellite communication circuit switched communication channels. This paper will describe the set of user-selectable cellular interoperable modes (cellular first/satellite second, etc.) provided by the Mobile Phone and described how they are implemented with the ground segment. Topics including roaming registration and cellular-to-satellite 'seamless' call handoff will be discussed, along with the relevant Interim Standard IS-41 Revision B Cellular Radiotelecommunications Intersystem Operations and IOS-553 Mobile Station - Land Station Compatibility Specification.

Memory Compression Techniques for Network Address Management in MPI

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

Guo, Yanfei; Archer, Charles J.; Blocksome, Michael

MPI allows applications to treat processes as a logical collection of integer ranks for each MPI communicator, while internally translating these logical ranks into actual network addresses. In current MPI implementations the management and lookup of such network addresses use memory sizes that are proportional to the number of processes in each communicator. In this paper, we propose a new mechanism, called AV-Rankmap, for managing such translation. AV-Rankmap takes advantage of logical patterns in rank-address mapping that most applications naturally tend to have, and it exploits the fact that some parts of network address structures are naturally more performance criticalmore » than others. It uses this information to compress the memory used for network address management. We demonstrate that AV-Rankmap can achieve performance similar to or better than that of other MPI implementations while using significantly less memory.« less

Time Allocation in Social Networks: Correlation Between Social Structure and Human Communication Dynamics

NASA Astrophysics Data System (ADS)

Miritello, Giovanna; Lara, Rubén; Moro, Esteban

Recent research has shown the deep impact of the dynamics of human interactions (or temporal social networks) on the spreading of information, opinion formation, etc. In general, the bursty nature of human interactions lowers the interaction between people to the extent that both the speed and reach of information diffusion are diminished. Using a large database of 20 million users of mobile phone calls we show evidence this effect is not homogeneous in the social network but in fact, there is a large correlation between this effect and the social topological structure around a given individual. In particular, we show that social relations of hubs in a network are relatively weaker from the dynamical point than those that are poorer connected in the information diffusion process. Our results show the importance of the temporal patterns of communication when analyzing and modeling dynamical process on social networks.

Conceptualising Changes to Pre-Service Teachers' Knowledge of How to Best Facilitate Learning in Mathematics: A TPACK Inspired Initiative

ERIC Educational Resources Information Center

Bate, Frank G.; Day, Lorraine; Macnish, Jean

2013-01-01

In 2010, the Australian Commonwealth government initiated an $8m project called Teaching Teachers for the Future. The aim of the project was to engage teacher educators in a professional learning network which focused on optimising exemplary use of information and communications technologies in teacher education. By taking part in this network,…

Design and Implementation of Online Communities

DTIC Science & Technology

2001-09-01

online community. In reality, the first online community predates even the ARPANET by over 100 years. The first “netizens” communicated on the 19th ...Century’s version of the Internet, which Tom Standage calls “The Victorian Internet” (Standage, 1998). The Victorian Internet was actually the...network of networks extending throughout much of the world. The similarities don’t stop there. The Victorian Internet spawned an extensive online

Hands-free human-machine interaction with voice

NASA Astrophysics Data System (ADS)

Juang, B. H.

2004-05-01

Voice is natural communication interface between a human and a machine. The machine, when placed in today's communication networks, may be configured to provide automation to save substantial operating cost, as demonstrated in AT&T's VRCP (Voice Recognition Call Processing), or to facilitate intelligent services, such as virtual personal assistants, to enhance individual productivity. These intelligent services often need to be accessible anytime, anywhere (e.g., in cars when the user is in a hands-busy-eyes-busy situation or during meetings where constantly talking to a microphone is either undersirable or impossible), and thus call for advanced signal processing and automatic speech recognition techniques which support what we call ``hands-free'' human-machine communication. These techniques entail a broad spectrum of technical ideas, ranging from use of directional microphones and acoustic echo cancellatiion to robust speech recognition. In this talk, we highlight a number of key techniques that were developed for hands-free human-machine communication in the mid-1990s after Bell Labs became a unit of Lucent Technologies. A video clip will be played to demonstrate the accomplishement.

A simple hyperbolic model for communication in parallel processing environments

NASA Technical Reports Server (NTRS)

Stoica, Ion; Sultan, Florin; Keyes, David

1994-01-01

We introduce a model for communication costs in parallel processing environments called the 'hyperbolic model,' which generalizes two-parameter dedicated-link models in an analytically simple way. Dedicated interprocessor links parameterized by a latency and a transfer rate that are independent of load are assumed by many existing communication models; such models are unrealistic for workstation networks. The communication system is modeled as a directed communication graph in which terminal nodes represent the application processes that initiate the sending and receiving of the information and in which internal nodes, called communication blocks (CBs), reflect the layered structure of the underlying communication architecture. The direction of graph edges specifies the flow of the information carried through messages. Each CB is characterized by a two-parameter hyperbolic function of the message size that represents the service time needed for processing the message. The parameters are evaluated in the limits of very large and very small messages. Rules are given for reducing a communication graph consisting of many to an equivalent two-parameter form, while maintaining an approximation for the service time that is exact in both large and small limits. The model is validated on a dedicated Ethernet network of workstations by experiments with communication subprograms arising in scientific applications, for which a tight fit of the model predictions with actual measurements of the communication and synchronization time between end processes is demonstrated. The model is then used to evaluate the performance of two simple parallel scientific applications from partial differential equations: domain decomposition and time-parallel multigrid. In an appropriate limit, we also show the compatibility of the hyperbolic model with the recently proposed LogP model.

Multidimensional human dynamics in mobile phone communications.

PubMed

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

2014-01-01

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

The Illinois Century Network: New Dimensions for Education in Illinois. A Vision for Communications and Computing Networking To Retain and Expand Illinois' Position as a World Leader by the Turn of the Century. Report and First-Phase Recommendations of the Higher Education Technology Task Force to the Illinois Board of Higher Education and the Illinois Community College Board.

ERIC Educational Resources Information Center

Illinois State Board of Higher Education, Springfield.

This proposal calls on the state of Illinois to initiate a statewide computing and telecommunications network that would give its residents access to higher education, advanced training, and electronic information resources. The proposed network, entitled Illinois Century Network, would link all higher education institutions in the state to…

Optimizing targeted vaccination across cyber-physical networks: an empirically based mathematical simulation study.

PubMed

Mones, Enys; Stopczynski, Arkadiusz; Pentland, Alex 'Sandy'; Hupert, Nathaniel; Lehmann, Sune

2018-01-01

Targeted vaccination, whether to minimize the forward transmission of infectious diseases or their clinical impact, is one of the 'holy grails' of modern infectious disease outbreak response, yet it is difficult to achieve in practice due to the challenge of identifying optimal targets in real time. If interruption of disease transmission is the goal, targeting requires knowledge of underlying person-to-person contact networks. Digital communication networks may reflect not only virtual but also physical interactions that could result in disease transmission, but the precise overlap between these cyber and physical networks has never been empirically explored in real-life settings. Here, we study the digital communication activity of more than 500 individuals along with their person-to-person contacts at a 5-min temporal resolution. We then simulate different disease transmission scenarios on the person-to-person physical contact network to determine whether cyber communication networks can be harnessed to advance the goal of targeted vaccination for a disease spreading on the network of physical proximity. We show that individuals selected on the basis of their closeness centrality within cyber networks (what we call 'cyber-directed vaccination') can enhance vaccination campaigns against diseases with short-range (but not full-range) modes of transmission. © 2018 The Author(s).

Analysis of Malicious Traffic in Modbus/TCP Communications

NASA Astrophysics Data System (ADS)

Kobayashi, Tiago H.; Batista, Aguinaldo B.; Medeiros, João Paulo S.; Filho, José Macedo F.; Brito, Agostinho M.; Pires, Paulo S. Motta

This paper presents the results of our analysis about the influence of Information Technology (IT) malicious traffic on an IP-based automation environment. We utilized a traffic generator, called MACE (Malicious trAffic Composition Environment), to inject malicious traffic in a Modbus/TCP communication system and a sniffer to capture and analyze network traffic. The realized tests show that malicious traffic represents a serious risk to critical information infrastructures. We show that this kind of traffic can increase latency of Modbus/TCP communication and that, in some cases, can put Modbus/TCP devices out of communication.

Understanding the Internet of Things

ERIC Educational Resources Information Center

Pierce, Dennis

2017-01-01

The universe of objects containing microprocessors or embedded sensors capable of communicating and transmitting information across networks is called the Internet of Things, and it has enormous implications for community colleges. Already, many colleges are saving time and money by monitoring and controlling "smart building" features…

TinyOS-based quality of service management in wireless sensor networks

USGS Publications Warehouse

Peterson, N.; Anusuya-Rangappa, L.; Shirazi, B.A.; Huang, R.; Song, W.-Z.; Miceli, M.; McBride, D.; Hurson, A.; LaHusen, R.

2009-01-01

Previously the cost and extremely limited capabilities of sensors prohibited Quality of Service (QoS) implementations in wireless sensor networks. With advances in technology, sensors are becoming significantly less expensive and the increases in computational and storage capabilities are opening the door for new, sophisticated algorithms to be implemented. Newer sensor network applications require higher data rates with more stringent priority requirements. We introduce a dynamic scheduling algorithm to improve bandwidth for high priority data in sensor networks, called Tiny-DWFQ. Our Tiny-Dynamic Weighted Fair Queuing scheduling algorithm allows for dynamic QoS for prioritized communications by continually adjusting the treatment of communication packages according to their priorities and the current level of network congestion. For performance evaluation, we tested Tiny-DWFQ, Tiny-WFQ (traditional WFQ algorithm implemented in TinyOS), and FIFO queues on an Imote2-based wireless sensor network and report their throughput and packet loss. Our results show that Tiny-DWFQ performs better in all test cases. ?? 2009 IEEE.

Seeking Information on Behalf of Others: An Analysis of Calls to a Spanish-Language Radio Health Program.

PubMed

Ramirez, A Susana; Leyva, Bryan; Graff, Kaitlin; Nelson, David E; Huerta, Elmer

2015-07-01

Spanish-monolingual Latinos account for 13% of U.S. residents and experience multiple barriers to effective health communication. Information intermediaries/proxies mediate between the linguistically isolated and health care providers. This study characterizes the information needs of surrogate callers and their subjects to a U.S.-based Spanish-language radio health program. Content analysis of calls placed (N = 281 calls). Women made 70% of calls; 39.1% of calls were on behalf of children, 11.0% on behalf of parents/older adults, and 18.5% on behalf of spouses/siblings/contemporary adults. Most common topics were disease symptoms/conditions (19.6%), cancer (13.9%), and reproduction/sexuality (12.9%). Calls for children were more likely than those for parents/other adults to pertain to current illness symptoms or conditions; calls for parents were more likely to be about cancer/chronic conditions. Half of all calls sought clarification about a previous medical encounter. Information-seeking surrogates may represent a useful strategy for linguistic minorities to overcome structural and individual barriers to health information access. Results suggest that Latinos are willing to seek information on behalf of friends and family and highlight the need for improved, culturally and linguistically appropriate health communication sources. Leveraging Latinos' natural familial social networks/willingness to share information may improve dissemination of culturally and linguistically appropriate health information. Further implications for patient activation and doctor-patient communication are discussed. © 2015 Society for Public Health Education.

Network Upgrade for the SLC: PEP II Network

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

Crane, M.; Call, M.; Clark, S.

2011-09-09

The PEP-II control system required a new network to support the system functions. This network, called CTLnet, is an FDDI/Ethernet based network using only TCP/IP protocols. An upgrade of the SLC Control System micro communications to use TCP/IP and SLCNET would allow all PEP-II control system nodes to use TCP/IP. CTLnet is private and separate from the SLAC public network. Access to nodes and control system functions is provided by multi-homed application servers with connections to both the private CTLnet and the SLAC public network. Monitoring and diagnostics are provided using a dedicated system. Future plans and current status informationmore » is included.« less

The Globalstar mobile satellite system for worldwide personal communications

NASA Astrophysics Data System (ADS)

Wiedeman, Robert A.; Viterbi, Andrew J.

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

The Globalstar mobile satellite system for worldwide personal communications

NASA Technical Reports Server (NTRS)

Wiedeman, Robert A.; Viterbi, Andrew J.

1993-01-01

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

Feasibility of NASA TT&C via Commercial Satellite Services

NASA Technical Reports Server (NTRS)

Mitchell, Carl W.; Weiss, Roland

1997-01-01

This report presents the results of a study to identify impact and driving requirements by implementing commercial satellite communications service into traditional National Aeronautics and Space Administration (NASA) space-ground communications. The NASA communication system is used to relay spacecraft and instrument commands, telemetry and science data. NASA's goal is to lower the cost of operation and increase the flexibility of spacecraft operations. Use of a commercial network offers the opportunity to contact a spacecraft on a nearly "on-demand" basis with ordinary phone calls to enable real time interaction with science events.

Telecommunications Programs Affecting Network Development.

ERIC Educational Resources Information Center

Norwood, Frank W.

In a recent issue of "Fortune," the leading article carried the predictive title, "The Coming Shake-Up in Telecommunications." Increasingly, the attention of the business community and the general public is being called to the emergence of such new and potentially revolutionary communications technologies as CATV (community…

Adaptive dynamical networks

NASA Astrophysics Data System (ADS)

Maslennikov, O. V.; Nekorkin, V. I.

2017-10-01

Dynamical networks are systems of active elements (nodes) interacting with each other through links. Examples are power grids, neural structures, coupled chemical oscillators, and communications networks, all of which are characterized by a networked structure and intrinsic dynamics of their interacting components. If the coupling structure of a dynamical network can change over time due to nodal dynamics, then such a system is called an adaptive dynamical network. The term ‘adaptive’ implies that the coupling topology can be rewired; the term ‘dynamical’ implies the presence of internal node and link dynamics. The main results of research on adaptive dynamical networks are reviewed. Key notions and definitions of the theory of complex networks are given, and major collective effects that emerge in adaptive dynamical networks are described.

Design and Implementation of a Lunar Communications Satellite and Server for the 2012 SISO Smackdown

NASA Technical Reports Server (NTRS)

Bulgatz, Dennis; Heater, Daniel; O'Neal, Daniel A.; Norris, Bryan; Schricker, Bradley C.

2012-01-01

Last year, the Simulation Interoperability Standards Organization (SISO) inaugurated the now annual High Level Architecture (HLA) Smackdown at the Spring Simulation Interoperability Workshop (SIW). A primary objective of the Smackdown event is to provide college students with hands-on experience in the High Level Architecture (HLA). The University of Alabama in Huntsville (UAHuntsville) fielded teams in 2011 and 2012. Both the 2011 and 2012 smackdown scenarios were a lunar resupply mission. The 2012 UAHuntsville fielded four federates: a communications network Federate called Lunar Communications and Navigation Satellite Service (LCANServ) for sending and receiving messages, a Lunar Satellite Constellation (LCANSat) to put in place radios needed by the communications network for Line-Of-Sight communication calculations, and 3D graphical displays of the orbiting satellites and a 3D visualization of the lunar surface activities. This paper concentrates on the first two federates by describing the functions, algorithms, the modular FOM, experiences, lessons learned and recommendations for future Smackdown events.

A Spectrum Access Based on Quality of Service (QoS) in Cognitive Radio Networks.

PubMed

Zhai, Linbo; Wang, Hua; Gao, Chuangen

2016-01-01

The quality of service (QoS) is important issue for cognitive radio networks. In the cognitive radio system, the licensed users, also called primary users (PUs), are authorized to utilize the wireless spectrum, while unlicensed users, also called secondary users (SUs), are not authorized to use the wireless spectrum. SUs access the wireless spectrum opportunistically when the spectrum is idle. While SUs use an idle channel, the instance that PUs come back makes SUs terminate their communications and leave the current channel. Therefore, quality of service (QoS) is difficult to be ensured for SUs. In this paper, we first propose an analysis model to obtain QoS for cognitive radio networks such as blocking probability, completed traffic and termination probability of SUs. When the primary users use the channels frequently, QoS of SUs is difficult to be ensured, especially the termination probability. Then, we propose a channel reservation scheme to improve QoS of SUs. The scheme makes the terminated SUs move to the reserved channels and keep on communications. Simulation results show that our scheme can improve QoS of SUs especially the termination probability with a little cost of blocking probability in dynamic environment.

Global synchronization of complex dynamical networks through digital communication with limited data rate.

PubMed

Wang, Yan-Wu; Bian, Tao; Xiao, Jiang-Wen; Wen, Changyun

2015-10-01

This paper studies the global synchronization of complex dynamical network (CDN) under digital communication with limited bandwidth. To realize the digital communication, the so-called uniform-quantizer-sets are introduced to quantize the states of nodes, which are then encoded and decoded by newly designed encoders and decoders. To meet the requirement of the bandwidth constraint, a scaling function is utilized to guarantee the quantizers having bounded inputs and thus achieving bounded real-time quantization levels. Moreover, a new type of vector norm is introduced to simplify the expression of the bandwidth limit. Through mathematical induction, a sufficient condition is derived to ensure global synchronization of the CDNs. The lower bound on the sum of the real-time quantization levels is analyzed for different cases. Optimization method is employed to relax the requirements on the network topology and to determine the minimum of such lower bound for each case, respectively. Simulation examples are also presented to illustrate the established results.

Teaching Networking: An Interpersonal Communication Competence Perspective

ERIC Educational Resources Information Center

Kokkonen, Lotta; Almonkari, Merja

2015-01-01

Modern working life calls for competences that enable people to be creative, innovative and effective. Studies looking at contemporary enterprises and organisations such as businesses and schools have shown that many of the qualifications that graduating students would need, including informal learning (see Gielen, Hoeve & Nieuwenhuis 2003),…

mDARAL: A Multi-Radio Version for the DARAL Routing Algorithm.

PubMed

Estévez, Francisco José; Castillo-Secilla, José María; González, Jesús; Olivares, Joaquín; Glösekötter, Peter

2017-02-09

Smart Cities are called to change the daily life of human beings. This concept permits improving the efficiency of our cities in several areas such as the use of water, energy consumption, waste treatment, and mobility both for people as well as vehicles throughout the city. This represents an interconnected scenario in which thousands of embedded devices need to work in a collaborative way both for sensing and modifying the environment properly. Under this scenario, the majority of devices will use wireless protocols for communicating among them, representing a challenge for optimizing the use of the electromagnetic spectrum. When the density of deployed nodes increases, the competition for using the physical medium becomes harder and, in consequence, traffic collisions will be higher, affecting data-rates in the communication process. This work presents mDARAL , a multi-radio routing algorithm based on the Dynamic and Adaptive Radio Algorithm ( DARAL ), which has the capability of isolating groups of nodes into sub-networks. The nodes of each sub-network will communicate among them using a dedicated radio frequency, thus isolating the use of the radio channel to a reduced number of nodes. Each sub-network will have a master node with two physical radios, one for communicating with its neighbours and the other for being the contact point among its group and other sub-networks. The communication among sub-networks is done through master nodes in a dedicated radio frequency. The algorithm works to maximize the overall performance of the network through the distribution of the traffic messages into unoccupied frequencies. The obtained results show that mDARAL achieves great improvement in terms of the number of control messages necessary to connect a node to the network, convergence time and energy consumption during the connection phase compared to DARAL .

mDARAL: A Multi-Radio Version for the DARAL Routing Algorithm

PubMed Central

Estévez, Francisco José; Castillo-Secilla, José María; González, Jesús; Olivares, Joaquín; Glösekötter, Peter

2017-01-01

Smart Cities are called to change the daily life of human beings. This concept permits improving the efficiency of our cities in several areas such as the use of water, energy consumption, waste treatment, and mobility both for people as well as vehicles throughout the city. This represents an interconnected scenario in which thousands of embedded devices need to work in a collaborative way both for sensing and modifying the environment properly. Under this scenario, the majority of devices will use wireless protocols for communicating among them, representing a challenge for optimizing the use of the electromagnetic spectrum. When the density of deployed nodes increases, the competition for using the physical medium becomes harder and, in consequence, traffic collisions will be higher, affecting data-rates in the communication process. This work presents mDARAL, a multi-radio routing algorithm based on the Dynamic and Adaptive Radio Algorithm (DARAL), which has the capability of isolating groups of nodes into sub-networks. The nodes of each sub-network will communicate among them using a dedicated radio frequency, thus isolating the use of the radio channel to a reduced number of nodes. Each sub-network will have a master node with two physical radios, one for communicating with its neighbours and the other for being the contact point among its group and other sub-networks. The communication among sub-networks is done through master nodes in a dedicated radio frequency. The algorithm works to maximize the overall performance of the network through the distribution of the traffic messages into unoccupied frequencies. The obtained results show that mDARAL achieves great improvement in terms of the number of control messages necessary to connect a node to the network, convergence time and energy consumption during the connection phase compared to DARAL. PMID:28208760

Towards a flexible middleware for context-aware pervasive and wearable systems.

PubMed

Muro, Marco; Amoretti, Michele; Zanichelli, Francesco; Conte, Gianni

2012-11-01

Ambient intelligence and wearable computing call for innovative hardware and software technologies, including a highly capable, flexible and efficient middleware, allowing for the reuse of existing pervasive applications when developing new ones. In the considered application domain, middleware should also support self-management, interoperability among different platforms, efficient communications, and context awareness. In the on-going "everything is networked" scenario scalability appears as a very important issue, for which the peer-to-peer (P2P) paradigm emerges as an appealing solution for connecting software components in an overlay network, allowing for efficient and balanced data distribution mechanisms. In this paper, we illustrate how all these concepts can be placed into a theoretical tool, called networked autonomic machine (NAM), implemented into a NAM-based middleware, and evaluated against practical problems of pervasive computing.

The role of communication and imitation in limit order markets

NASA Astrophysics Data System (ADS)

Tedeschi, G.; Iori, G.; Gallegati, M.

2009-10-01

In this paper we develop an order driver market model with heterogeneous traders that imitate each other on different network structures. We assess how imitations among otherway noise traders, can give rise to well known stylized facts such as fat tails and volatility clustering. We examine the impact of communication and imitation on the statistical properties of prices and order flows when changing the networks' structure, and show that the imitation of a given, fixed agent, called “guru", can generate clustering of volatility in the model. We also find a positive correlation between volatility and bid-ask spread, and between fat-tailed fluctuations in asset prices and gap sizes in the order book. in here

Facility for the evaluation of space communications and related systems

NASA Technical Reports Server (NTRS)

Kerczewski, Robert J.; Svoboda, James S.; Kachmar, Brian A.

1995-01-01

NASA Lewis Research Center's Communications Projects Branch has developed a facility for the evaluation of space communications systems and related types of systems, called the Advanced Space Communications (ASC) Laboratory. The ASC Lab includes instrumentation, testbed hardware, and experiment control and monitor software for the evaluation of components, subsystems, systems, and networks. The ASC lab has capabilities to perform radiofrequency (RF), microwave, and millimeter-wave characterizations as well as measurements using low, medium, or high data rate digital signals. In addition to laboratory measurements, the ASC Lab also includes integrated satellite ground terminals allowing experimentation and measurements accessing operational satellites through real space links.

A satellite system for land-mobile communications in Europe

NASA Technical Reports Server (NTRS)

Bartholome, P.; Rogard, R.

1988-01-01

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

Using Social Networking to Understand Social Networks: Analysis of a Mobile Phone Closed User Group Used by a Ghanaian Health Team

PubMed Central

Akosah, Eric; Ohemeng-Dapaah, Seth; Sakyi Baah, Joseph; Kanter, Andrew S

2013-01-01

Background The network structure of an organization influences how well or poorly an organization communicates and manages its resources. In the Millennium Villages Project site in Bonsaaso, Ghana, a mobile phone closed user group has been introduced for use by the Bonsaaso Millennium Villages Project Health Team and other key individuals. No assessment on the benefits or barriers of the use of the closed user group had been carried out. Objective The purpose of this research was to make the case for the use of social network analysis methods to be applied in health systems research—specifically related to mobile health. Methods This study used mobile phone voice records of, conducted interviews with, and reviewed call journals kept by a mobile phone closed user group consisting of the Bonsaaso Millennium Villages Project Health Team. Social network analysis methodology complemented by a qualitative component was used. Monthly voice data of the closed user group from Airtel Bharti Ghana were analyzed using UCINET and visual depictions of the network were created using NetDraw. Interviews and call journals kept by informants were analyzed using NVivo. Results The methodology was successful in helping identify effective organizational structure. Members of the Health Management Team were the more central players in the network, rather than the Community Health Nurses (who might have been expected to be central). Conclusions Social network analysis methodology can be used to determine the most productive structure for an organization or team, identify gaps in communication, identify key actors with greatest influence, and more. In conclusion, this methodology can be a useful analytical tool, especially in the context of mobile health, health services, and operational and managerial research. PMID:23552721

Using social networking to understand social networks: analysis of a mobile phone closed user group used by a Ghanaian health team.

PubMed

Kaonga, Nadi Nina; Labrique, Alain; Mechael, Patricia; Akosah, Eric; Ohemeng-Dapaah, Seth; Sakyi Baah, Joseph; Kodie, Richmond; Kanter, Andrew S; Levine, Orin

2013-04-03

The network structure of an organization influences how well or poorly an organization communicates and manages its resources. In the Millennium Villages Project site in Bonsaaso, Ghana, a mobile phone closed user group has been introduced for use by the Bonsaaso Millennium Villages Project Health Team and other key individuals. No assessment on the benefits or barriers of the use of the closed user group had been carried out. The purpose of this research was to make the case for the use of social network analysis methods to be applied in health systems research--specifically related to mobile health. This study used mobile phone voice records of, conducted interviews with, and reviewed call journals kept by a mobile phone closed user group consisting of the Bonsaaso Millennium Villages Project Health Team. Social network analysis methodology complemented by a qualitative component was used. Monthly voice data of the closed user group from Airtel Bharti Ghana were analyzed using UCINET and visual depictions of the network were created using NetDraw. Interviews and call journals kept by informants were analyzed using NVivo. The methodology was successful in helping identify effective organizational structure. Members of the Health Management Team were the more central players in the network, rather than the Community Health Nurses (who might have been expected to be central). Social network analysis methodology can be used to determine the most productive structure for an organization or team, identify gaps in communication, identify key actors with greatest influence, and more. In conclusion, this methodology can be a useful analytical tool, especially in the context of mobile health, health services, and operational and managerial research.

U.S. Initiatives to Promote Global Internet Freedom: Issues, Policy, and Technology

DTIC Science & Technology

2010-03-17

video sharing sites, and other tools of today’s communications technology has proven to be an unprecedented and often disruptive force in some closed...using newer tools, such as blogs, social networks, video sharing sites, and other aspects of today’s communications technology to express their...Iranians sent VOA over 300 videos a day, along with thousands of still pictures, e-mails, and telephone calls to the agency.2 A variety of control

Challenges in sending large radiology images over military communications channels

NASA Astrophysics Data System (ADS)

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.

Quantum generalisation of feedforward neural networks

NASA Astrophysics Data System (ADS)

Wan, Kwok Ho; Dahlsten, Oscar; Kristjánsson, Hlér; Gardner, Robert; Kim, M. S.

2017-09-01

We propose a quantum generalisation of a classical neural network. The classical neurons are firstly rendered reversible by adding ancillary bits. Then they are generalised to being quantum reversible, i.e., unitary (the classical networks we generalise are called feedforward, and have step-function activation functions). The quantum network can be trained efficiently using gradient descent on a cost function to perform quantum generalisations of classical tasks. We demonstrate numerically that it can: (i) compress quantum states onto a minimal number of qubits, creating a quantum autoencoder, and (ii) discover quantum communication protocols such as teleportation. Our general recipe is theoretical and implementation-independent. The quantum neuron module can naturally be implemented photonically.

Memory Network For Distributed Data Processors

NASA Technical Reports Server (NTRS)

Bolen, David; Jensen, Dean; Millard, ED; Robinson, Dave; Scanlon, George

1992-01-01

Universal Memory Network (UMN) is modular, digital data-communication system enabling computers with differing bus architectures to share 32-bit-wide data between locations up to 3 km apart with less than one millisecond of latency. Makes it possible to design sophisticated real-time and near-real-time data-processing systems without data-transfer "bottlenecks". This enterprise network permits transmission of volume of data equivalent to an encyclopedia each second. Facilities benefiting from Universal Memory Network include telemetry stations, simulation facilities, power-plants, and large laboratories or any facility sharing very large volumes of data. Main hub of UMN is reflection center including smaller hubs called Shared Memory Interfaces.

Incoherence-Mediated Remote Synchronization

NASA Astrophysics Data System (ADS)

Zhang, Liyue; Motter, Adilson E.; Nishikawa, Takashi

2017-04-01

In previously identified forms of remote synchronization between two nodes, the intermediate portion of the network connecting the two nodes is not synchronized with them but generally exhibits some coherent dynamics. Here we report on a network phenomenon we call incoherence-mediated remote synchronization (IMRS), in which two noncontiguous parts of the network are identically synchronized while the dynamics of the intermediate part is statistically and information-theoretically incoherent. We identify mirror symmetry in the network structure as a mechanism allowing for such behavior, and show that IMRS is robust against dynamical noise as well as against parameter changes. IMRS may underlie neuronal information processing and potentially lead to network solutions for encryption key distribution and secure communication.

The evolving role of telecommunications switching

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

Personick, S.D.

1993-01-01

There are many forces impacting on the evolution of switching vis-a-vis its role in telecommunications/information networking. Many of the technologies that in the past 15 years have enabled the cost reductions the industry has experienced in digital switches, and the emergence of intelligent networks are now also enabling a wide range of new end-user applications. Many of these applications are rapidly emerging and evolving to meet the, as yet, uncertain needs of the marketplace. There is an explosion of new ideas for applications involving personalized, nomadic communications, multimedia communications, and information access. Some of these will succeed in the marketplacemore » and some will not. There is a continuing emergence of new and improved underlying electronic and photonic technologies and, most recently, the emergence of reliable, secure distributed computing, communications, and management environments. End-user CPE and servers have become increasingly powerful and cost effective as places to locate session (call) management and session enabling objects such as user-interfaces, directories, agents, multimedia bridges, and storage/server subsystems. Not only are dramatically new paradigms for building networks to support existing applications possible, but there is a pressing need to support the emerging and evolving new applications in a timely way. Competition is accelerating the rate of introduction of new technologies, architectures, and telecommunication services. Every aspect of the business is being reexamined to find better ways of meeting customers' needs more efficiently. Meanwhile, as new applications become deployed, there are increasing pressures to provide for security, privacy, and network integrity. This article reviews the author's personal views (many of which are widely shared by others) of the implications of all of these forces on what we traditionally call telecommunications switching. 10 refs.« less

Communication network for decentralized remote tele-science during the Spacelab mission IML-2

NASA Technical Reports Server (NTRS)

Christ, Uwe; Schulz, Klaus-Juergen; Incollingo, Marco

1994-01-01

The ESA communication network for decentralized remote telescience during the Spacelab mission IML-2, called Interconnection Ground Subnetwork (IGS), provided data, voice conferencing, video distribution/conferencing and high rate data services to 5 remote user centers in Europe. The combination of services allowed the experimenters to interact with their experiments as they would normally do from the Payload Operations Control Center (POCC) at MSFC. In addition, to enhance their science results, they were able to make use of reference facilities and computing resources in their home laboratory, which typically are not available in the POCC. Characteristics of the IML-2 communications implementation were the adaptation to the different user needs based on modular service capabilities of IGS and the cost optimization for the connectivity. This was achieved by using a combination of traditional leased lines, satellite based VSAT connectivity and N-ISDN according to the simulation and mission schedule for each remote site. The central management system of IGS allows minimization of staffing and the involvement of communications personnel at the remote sites. The successful operation of IGS for IML-2 as a precursor network for the Columbus Orbital Facility (COF) has proven the concept for communications to support the operation of the COF decentralized scenario.

How to pass information and deliver energy to a network of implantable devices within the human body.

PubMed

Sun, Mingui; Hackworth, Steven A; Tang, Zhide; Gilbert, Gary; Cardin, Sylvain; Sclabassi, Robert J

2007-01-01

It has been envisioned that a body network can be built to collect data from, and transport information to, implanted miniature devices at multiple sites within the human body. Currently, two problems of utmost importance remain unsolved: 1) how to link information between a pair of implants at a distance? and 2) how to provide electric power to these implants allowing them to function and communicate? In this paper, we present new solutions to these problems by minimizing the intra-body communication distances. We show that, based on a study of human anatomy, the maximum distance from the body surface to the deepest point inside the body is approximately 15 cm. This finding provides an upper bound for the lengths of communication pathways required to reach the body's interior. We also show that these pathways do not have to cross any joins within the body. In order to implement the envisioned body network, we present the design of a new device, called an energy pad. This small-size, light-weight device can easily interface with the skin to perform data communication with, and supply power to, miniature implants.

Generation of distributed W-states over long distances

NASA Astrophysics Data System (ADS)

Li, Yi

2017-08-01

Ultra-secure quantum communication between distant locations requires distributed entangled states between nodes. Various methodologies have been proposed to tackle this technological challenge, of which the so-called DLCZ protocol is the most promising and widely adopted scheme. This paper aims to extend this well-known protocol to a multi-node setting where the entangled W-state is generated between nodes over long distances. The generation of multipartite W-states is the foundation of quantum networks, paving the way for quantum communication and distributed quantum computation.

Data-Gathering Scheme Using AUVs in Large-Scale Underwater Sensor Networks: A Multihop Approach

PubMed Central

Khan, Jawaad Ullah; Cho, Ho-Shin

2016-01-01

In this paper, we propose a data-gathering scheme for hierarchical underwater sensor networks, where multiple Autonomous Underwater Vehicles (AUVs) are deployed over large-scale coverage areas. The deployed AUVs constitute an intermittently connected multihop network through inter-AUV synchronization (in this paper, synchronization means an interconnection between nodes for communication) for forwarding data to the designated sink. In such a scenario, the performance of the multihop communication depends upon the synchronization among the vehicles. The mobility parameters of the vehicles vary continuously because of the constantly changing underwater currents. The variations in the AUV mobility parameters reduce the inter-AUV synchronization frequency contributing to delays in the multihop communication. The proposed scheme improves the AUV synchronization frequency by permitting neighboring AUVs to share their status information via a pre-selected node called an agent-node at the static layer of the network. We evaluate the proposed scheme in terms of the AUV synchronization frequency, vertical delay (node→AUV), horizontal delay (AUV→AUV), end-to-end delay, and the packet loss ratio. Simulation results show that the proposed scheme significantly reduces the aforementioned delays without the synchronization time-out process employed in conventional works. PMID:27706042

Data-Gathering Scheme Using AUVs in Large-Scale Underwater Sensor Networks: A Multihop Approach.

PubMed

Khan, Jawaad Ullah; Cho, Ho-Shin

2016-09-30

In this paper, we propose a data-gathering scheme for hierarchical underwater sensor networks, where multiple Autonomous Underwater Vehicles (AUVs) are deployed over large-scale coverage areas. The deployed AUVs constitute an intermittently connected multihop network through inter-AUV synchronization (in this paper, synchronization means an interconnection between nodes for communication) for forwarding data to the designated sink. In such a scenario, the performance of the multihop communication depends upon the synchronization among the vehicles. The mobility parameters of the vehicles vary continuously because of the constantly changing underwater currents. The variations in the AUV mobility parameters reduce the inter-AUV synchronization frequency contributing to delays in the multihop communication. The proposed scheme improves the AUV synchronization frequency by permitting neighboring AUVs to share their status information via a pre-selected node called an agent-node at the static layer of the network. We evaluate the proposed scheme in terms of the AUV synchronization frequency, vertical delay (node→AUV), horizontal delay (AUV→AUV), end-to-end delay, and the packet loss ratio. Simulation results show that the proposed scheme significantly reduces the aforementioned delays without the synchronization time-out process employed in conventional works.

Learning Perfectly Secure Cryptography to Protect Communications with Adversarial Neural Cryptography

PubMed Central

2018-01-01

Researches in Artificial Intelligence (AI) have achieved many important breakthroughs, especially in recent years. In some cases, AI learns alone from scratch and performs human tasks faster and better than humans. With the recent advances in AI, it is natural to wonder whether Artificial Neural Networks will be used to successfully create or break cryptographic algorithms. Bibliographic review shows the main approach to this problem have been addressed throughout complex Neural Networks, but without understanding or proving the security of the generated model. This paper presents an analysis of the security of cryptographic algorithms generated by a new technique called Adversarial Neural Cryptography (ANC). Using the proposed network, we show limitations and directions to improve the current approach of ANC. Training the proposed Artificial Neural Network with the improved model of ANC, we show that artificially intelligent agents can learn the unbreakable One-Time Pad (OTP) algorithm, without human knowledge, to communicate securely through an insecure communication channel. This paper shows in which conditions an AI agent can learn a secure encryption scheme. However, it also shows that, without a stronger adversary, it is more likely to obtain an insecure one. PMID:29695066

Learning Perfectly Secure Cryptography to Protect Communications with Adversarial Neural Cryptography.

PubMed

Coutinho, Murilo; de Oliveira Albuquerque, Robson; Borges, Fábio; García Villalba, Luis Javier; Kim, Tai-Hoon

2018-04-24

Researches in Artificial Intelligence (AI) have achieved many important breakthroughs, especially in recent years. In some cases, AI learns alone from scratch and performs human tasks faster and better than humans. With the recent advances in AI, it is natural to wonder whether Artificial Neural Networks will be used to successfully create or break cryptographic algorithms. Bibliographic review shows the main approach to this problem have been addressed throughout complex Neural Networks, but without understanding or proving the security of the generated model. This paper presents an analysis of the security of cryptographic algorithms generated by a new technique called Adversarial Neural Cryptography (ANC). Using the proposed network, we show limitations and directions to improve the current approach of ANC. Training the proposed Artificial Neural Network with the improved model of ANC, we show that artificially intelligent agents can learn the unbreakable One-Time Pad (OTP) algorithm, without human knowledge, to communicate securely through an insecure communication channel. This paper shows in which conditions an AI agent can learn a secure encryption scheme. However, it also shows that, without a stronger adversary, it is more likely to obtain an insecure one.

PISA: Federated Search in P2P Networks with Uncooperative Peers

NASA Astrophysics Data System (ADS)

Ren, Zujie; Shou, Lidan; Chen, Gang; Chen, Chun; Bei, Yijun

Recently, federated search in P2P networks has received much attention. Most of the previous work assumed a cooperative environment where each peer can actively participate in information publishing and distributed document indexing. However, little work has addressed the problem of incorporating uncooperative peers, which do not publish their own corpus statistics, into a network. This paper presents a P2P-based federated search framework called PISA which incorporates uncooperative peers as well as the normal ones. In order to address the indexing needs for uncooperative peers, we propose a novel heuristic query-based sampling approach which can obtain high-quality resource descriptions from uncooperative peers at relatively low communication cost. We also propose an effective method called RISE to merge the results returned by uncooperative peers. Our experimental results indicate that PISA can provide quality search results, while utilizing the uncooperative peers at a low cost.

Ethernet access network based on free-space optic deployment technology

NASA Astrophysics Data System (ADS)

Gebhart, Michael; Leitgeb, Erich; Birnbacher, Ulla; Schrotter, Peter

2004-06-01

The satisfaction of all communication needs from single households and business companies over a single access infrastructure is probably the most challenging topic in communications technology today. But even though the so-called "Last Mile Access Bottleneck" is well known since more than ten years and many distribution technologies have been tried out, the optimal solution has not yet been found and paying commercial access networks offering all service classes are still rare today. Conventional services like telephone, radio and TV, as well as new and emerging services like email, web browsing, online-gaming, video conferences, business data transfer or external data storage can all be transmitted over the well known and cost effective Ethernet networking protocol standard. Key requirements for the deployment technology driven by the different services are high data rates to the single customer, security, moderate deployment costs and good scalability to number and density of users, quick and flexible deployment without legal impediments and high availability, referring to the properties of optical and wireless communication. We demonstrate all elements of an Ethernet Access Network based on Free Space Optic distribution technology. Main physical parts are Central Office, Distribution Network and Customer Equipment. Transmission of different services, as well as configuration, service upgrades and remote control of the network are handled by networking features over one FSO connection. All parts of the network are proven, the latest commercially available technology. The set up is flexible and can be adapted to any more specific need if required.

CSRQ: Communication-Efficient Secure Range Queries in Two-Tiered Sensor Networks

PubMed Central

Dai, Hua; Ye, Qingqun; Yang, Geng; Xu, Jia; He, Ruiliang

2016-01-01

In recent years, we have seen many applications of secure query in two-tiered wireless sensor networks. Storage nodes are responsible for storing data from nearby sensor nodes and answering queries from Sink. It is critical to protect data security from a compromised storage node. In this paper, the Communication-efficient Secure Range Query (CSRQ)—a privacy and integrity preserving range query protocol—is proposed to prevent attackers from gaining information of both data collected by sensor nodes and queries issued by Sink. To preserve privacy and integrity, in addition to employing the encoding mechanisms, a novel data structure called encrypted constraint chain is proposed, which embeds the information of integrity verification. Sink can use this encrypted constraint chain to verify the query result. The performance evaluation shows that CSRQ has lower communication cost than the current range query protocols. PMID:26907293

WITS - A Coaxial Cable Bus Network for Medical Applications

PubMed Central

LaSonde, Clarence J.

1980-01-01

Walter Reed ARMY Medical Center has been serving as a Army test bed for coaxial cable-based local area networks since early 1978. This particular network, called the WRAMC Information Transfer System (WITS), carries commercial television, FM radio, closed-circuit TV and maintenance intercom audio, as well as digital data. The technology has proven successful. Broadband coaxial cable systems provide an opportunity to realize communications architectures that are flexible, highly reliable, and inexpensive. They are particularly appropriate for use in medical facilities where applications change over time and when many and varied systems are required to interact together.

GSFC_20171127_M12791_SpaceComm

NASA Image and Video Library

2017-11-27

#CyberMonday is one of the biggest online shopping days of the year. We're investigating how to bring cyber to outer space by developing new space communications technology. Space communications is very difficult because missions don't always have a full bandwidth connection with Earth. Reliably delivering data from missions to different destinations across not-always-connected paths currently requires a lot of advanced planning. A technology called Disruption Tolerant Networking will change all that. Space Communications Architect, Dave Israel and Exploration and Space Communications Outreach Lead, Amber Jacobson break down the technology. Facebook Live recording from Monday, November 27, 2017. For full resolution file go to: https://svs.gsfc.nasa.gov/12791

Business use of satellite communications

NASA Astrophysics Data System (ADS)

Edelson, B. I.; Cooper, R. S.

1982-02-01

The development, systems technology, and future applications of digital transmission systems for business use of satellite systems are explored. Intelsat currently has 22 satellites in space, applied mostly to data, telephone, and television transmission. An all digital communications network called the Integrated Services Digital Network is replacing the former, analog, systems with wideband digital transmission for voice, data, video, and industrial control information, with domestic satellites serving as the central node of transmissions in a service area. The digital systems are faster than the analog systems, and the U.S. Postal Service is developing an electronic mail system with six other countries. Various magazines are now teleprinted in various locations from broadcasts from a central source, and chain stores are employing data transmission for centralized management, inventory, and procurement.

Social-aware data dissemination in opportunistic mobile social networks

NASA Astrophysics Data System (ADS)

Yang, Yibo; Zhao, Honglin; Ma, Jinlong; Han, Xiaowei

Opportunistic Mobile Social Networks (OMSNs), formed by mobile users with social relationships and characteristics, enhance spontaneous communication among users that opportunistically encounter each other. Such networks can be exploited to improve the performance of data forwarding. Discovering optimal relay nodes is one of the important issues for efficient data propagation in OMSNs. Although traditional centrality definitions to identify the nodes features in network, they cannot identify effectively the influential nodes for data dissemination in OMSNs. Existing protocols take advantage of spatial contact frequency and social characteristics to enhance transmission performance. However, existing protocols have not fully exploited the benefits of the relations and the effects between geographical information, social features and user interests. In this paper, we first evaluate these three characteristics of users and design a routing protocol called Geo-Social-Interest (GSI) protocol to select optimal relay nodes. We compare the performance of GSI using real INFOCOM06 data sets. The experiment results demonstrate that GSI overperforms the other protocols with highest data delivery ratio and low communication overhead.

78 FR 59633 - Wireless Telecommunications Bureau Opens Docket To Seek Comment on DISH Network Corporation's...

Federal Register 2010, 2011, 2012, 2013, 2014

2013-09-27

... inspection during regular business hours in the FCC Reference Center, Federal Communications Commission, 445... LLC and New DBSD Satellite Services G.P. (collectively, DISH), filed a Petition for Waiver and a... held by its wholly-owned subsidiaries, Gamma Acquisition LLC (Call Signs T060430001-T060430176) and New...

Adaptive search in mobile peer-to-peer databases

NASA Technical Reports Server (NTRS)

Wolfson, Ouri (Inventor); Xu, Bo (Inventor)

2010-01-01

Information is stored in a plurality of mobile peers. The peers communicate in a peer to peer fashion, using a short-range wireless network. Occasionally, a peer initiates a search for information in the peer to peer network by issuing a query. Queries and pieces of information, called reports, are transmitted among peers that are within a transmission range. For each search additional peers are utilized, wherein these additional peers search and relay information on behalf of the originator of the search.

The Aerospace Energy Systems Laboratory: A BITBUS networking application

NASA Technical Reports Server (NTRS)

Glover, Richard D.; Oneill-Rood, Nora

1989-01-01

The NASA Ames-Dryden Flight Research Facility developed a computerized aircraft battery servicing facility called the Aerospace Energy Systems Laboratory (AESL). This system employs distributed processing with communications provided by a 2.4-megabit BITBUS local area network. Customized handlers provide real time status, remote command, and file transfer protocols between a central system running the iRMX-II operating system and ten slave stations running the iRMX-I operating system. The hardware configuration and software components required to implement this BITBUS application are required.

Wireless physical layer security

NASA Astrophysics Data System (ADS)

Poor, H. Vincent; Schaefer, Rafael F.

2017-01-01

Security in wireless networks has traditionally been considered to be an issue to be addressed separately from the physical radio transmission aspects of wireless systems. However, with the emergence of new networking architectures that are not amenable to traditional methods of secure communication such as data encryption, there has been an increase in interest in the potential of the physical properties of the radio channel itself to provide communications security. Information theory provides a natural framework for the study of this issue, and there has been considerable recent research devoted to using this framework to develop a greater understanding of the fundamental ability of the so-called physical layer to provide security in wireless networks. Moreover, this approach is also suggestive in many cases of coding techniques that can approach fundamental limits in practice and of techniques for other security tasks such as authentication. This paper provides an overview of these developments.

Wireless physical layer security.

PubMed

Poor, H Vincent; Schaefer, Rafael F

2017-01-03

Security in wireless networks has traditionally been considered to be an issue to be addressed separately from the physical radio transmission aspects of wireless systems. However, with the emergence of new networking architectures that are not amenable to traditional methods of secure communication such as data encryption, there has been an increase in interest in the potential of the physical properties of the radio channel itself to provide communications security. Information theory provides a natural framework for the study of this issue, and there has been considerable recent research devoted to using this framework to develop a greater understanding of the fundamental ability of the so-called physical layer to provide security in wireless networks. Moreover, this approach is also suggestive in many cases of coding techniques that can approach fundamental limits in practice and of techniques for other security tasks such as authentication. This paper provides an overview of these developments.

Agreement dynamics on interaction networks with diverse topologies

NASA Astrophysics Data System (ADS)

Barrat, Alain; Baronchelli, Andrea; Dall'Asta, Luca; Loreto, Vittorio

2007-06-01

We review the behavior of a recently introduced model of agreement dynamics, called the "Naming Game." This model describes the self-organized emergence of linguistic conventions and the establishment of simple communication systems in a population of agents with pairwise local interactions. The mechanisms of convergence towards agreement strongly depend on the network of possible interactions between the agents. In particular, the mean-field case in which all agents communicate with all the others is not efficient, since a large temporary memory is requested for the agents. On the other hand, regular lattice topologies lead to a fast local convergence but to a slow global dynamics similar to coarsening phenomena. The embedding of the agents in a small-world network represents an interesting tradeoff: a local consensus is easily reached, while the long-range links allow to bypass coarsening-like convergence. We also consider alternative adaptive strategies which can lead to faster global convergence.

Wireless physical layer security

PubMed Central

Schaefer, Rafael F.

2017-01-01

Security in wireless networks has traditionally been considered to be an issue to be addressed separately from the physical radio transmission aspects of wireless systems. However, with the emergence of new networking architectures that are not amenable to traditional methods of secure communication such as data encryption, there has been an increase in interest in the potential of the physical properties of the radio channel itself to provide communications security. Information theory provides a natural framework for the study of this issue, and there has been considerable recent research devoted to using this framework to develop a greater understanding of the fundamental ability of the so-called physical layer to provide security in wireless networks. Moreover, this approach is also suggestive in many cases of coding techniques that can approach fundamental limits in practice and of techniques for other security tasks such as authentication. This paper provides an overview of these developments. PMID:28028211

Efficient massively parallel simulation of dynamic channel assignment schemes for wireless cellular communications

NASA Technical Reports Server (NTRS)

Greenberg, Albert G.; Lubachevsky, Boris D.; Nicol, David M.; Wright, Paul E.

1994-01-01

Fast, efficient parallel algorithms are presented for discrete event simulations of dynamic channel assignment schemes for wireless cellular communication networks. The driving events are call arrivals and departures, in continuous time, to cells geographically distributed across the service area. A dynamic channel assignment scheme decides which call arrivals to accept, and which channels to allocate to the accepted calls, attempting to minimize call blocking while ensuring co-channel interference is tolerably low. Specifically, the scheme ensures that the same channel is used concurrently at different cells only if the pairwise distances between those cells are sufficiently large. Much of the complexity of the system comes from ensuring this separation. The network is modeled as a system of interacting continuous time automata, each corresponding to a cell. To simulate the model, conservative methods are used; i.e., methods in which no errors occur in the course of the simulation and so no rollback or relaxation is needed. Implemented on a 16K processor MasPar MP-1, an elegant and simple technique provides speedups of about 15 times over an optimized serial simulation running on a high speed workstation. A drawback of this technique, typical of conservative methods, is that processor utilization is rather low. To overcome this, new methods were developed that exploit slackness in event dependencies over short intervals of time, thereby raising the utilization to above 50 percent and the speedup over the optimized serial code to about 120 times.

Practical Considerations in the Implementation of Collaborative Beamforming on Wireless Sensor Networks

PubMed Central

Felici-Castell, Santiago; Navarro, Enrique A.; Pérez-Solano, Juan J.; Segura-García, Jaume; García-Pineda, Miguel

2017-01-01

Wireless Sensor Networks (WSNs) are composed of spatially distributed autonomous sensor devices, named motes. These motes have their own power supply, processing unit, sensors and wireless communications However with many constraints, such as limited energy, bandwidth and computational capabilities. In these networks, at least one mote called a sink, acts as a gateway to connect with other networks. These sensor networks run monitoring applications and then the data gathered by these motes needs to be retrieved by the sink. When this sink is located in the far field, there have been many proposals in the literature based on Collaborative Beamforming (CB), also known as Distributed or Cooperative Beamforming, for these long range communications to reach the sink. In this paper, we conduct a thorough study of the related work and analyze the requirements to do CB. In order to implement these communications in real scenarios, we will consider if these requirements and the assumptions made are feasible from the point of view of commercial motes and their constraints. In addition, we will go a step further and will consider different alternatives, by relaxing these requirements, trying to find feasible assumptions to carry out these types of communications with commercial motes. This research considers the nonavailability of a central clock that synchronizes all motes in the WSN, and all motes have identical hardware. This is a feasibility study to do CB on WSN, using a simulated scenario with randomized delays obtained from experimental data from commercial motes. PMID:28134753

Practical Considerations in the Implementation of Collaborative Beamforming on Wireless Sensor Networks.

PubMed

Felici-Castell, Santiago; Navarro, Enrique A; Pérez-Solano, Juan J; Segura-García, Jaume; García-Pineda, Miguel

2017-01-26

Wireless Sensor Networks (WSNs) are composed of spatially distributed autonomous sensor devices, named motes. These motes have their own power supply, processing unit, sensors and wireless communications However with many constraints, such as limited energy, bandwidth and computational capabilities. In these networks, at least one mote called a sink, acts as a gateway to connect with other networks. These sensor networks run monitoring applications and then the data gathered by these motes needs to be retrieved by the sink. When this sink is located in the far field, there have been many proposals in the literature based on Collaborative Beamforming (CB), also known as Distributed or Cooperative Beamforming, for these long range communications to reach the sink. In this paper, we conduct a thorough study of the related work and analyze the requirements to do CB. In order to implement these communications in real scenarios, we will consider if these requirements and the assumptions made are feasible from the point of view of commercial motes and their constraints. In addition, we will go a step further and will consider different alternatives, by relaxing these requirements, trying to find feasible assumptions to carry out these types of communications with commercial motes. This research considers the nonavailability of a central clock that synchronizes all motes in the WSN, and all motes have identical hardware. This is a feasibility study to do CB on WSN, using a simulated scenario with randomized delays obtained from experimental data from commercial motes.

An Energy-Efficient and High-Quality Video Transmission Architecture in Wireless Video-Based Sensor Networks.

PubMed

Aghdasi, Hadi S; Abbaspour, Maghsoud; Moghadam, Mohsen Ebrahimi; Samei, Yasaman

2008-08-04

Technological progress in the fields of Micro Electro-Mechanical Systems (MEMS) and wireless communications and also the availability of CMOS cameras, microphones and small-scale array sensors, which may ubiquitously capture multimedia content from the field, have fostered the development of low-cost limited resources Wireless Video-based Sensor Networks (WVSN). With regards to the constraints of videobased sensor nodes and wireless sensor networks, a supporting video stream is not easy to implement with the present sensor network protocols. In this paper, a thorough architecture is presented for video transmission over WVSN called Energy-efficient and high-Quality Video transmission Architecture (EQV-Architecture). This architecture influences three layers of communication protocol stack and considers wireless video sensor nodes constraints like limited process and energy resources while video quality is preserved in the receiver side. Application, transport, and network layers are the layers in which the compression protocol, transport protocol, and routing protocol are proposed respectively, also a dropping scheme is presented in network layer. Simulation results over various environments with dissimilar conditions revealed the effectiveness of the architecture in improving the lifetime of the network as well as preserving the video quality.

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

Not Available

The Computing and Communications (C) Division is responsible for the Laboratory's Integrated Computing Network (ICN) as well as Laboratory-wide communications. Our computing network, used by 8,000 people distributed throughout the nation, constitutes one of the most powerful scientific computing facilities in the world. In addition to the stable production environment of the ICN, we have taken a leadership role in high-performance computing and have established the Advanced Computing Laboratory (ACL), the site of research on experimental, massively parallel computers; high-speed communication networks; distributed computing; and a broad variety of advanced applications. The computational resources available in the ACL are ofmore » the type needed to solve problems critical to national needs, the so-called Grand Challenge'' problems. The purpose of this publication is to inform our clients of our strategic and operating plans in these important areas. We review major accomplishments since late 1990 and describe our strategic planning goals and specific projects that will guide our operations over the next few years. Our mission statement, planning considerations, and management policies and practices are also included.« less

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

Not Available

The Computing and Communications (C) Division is responsible for the Laboratory`s Integrated Computing Network (ICN) as well as Laboratory-wide communications. Our computing network, used by 8,000 people distributed throughout the nation, constitutes one of the most powerful scientific computing facilities in the world. In addition to the stable production environment of the ICN, we have taken a leadership role in high-performance computing and have established the Advanced Computing Laboratory (ACL), the site of research on experimental, massively parallel computers; high-speed communication networks; distributed computing; and a broad variety of advanced applications. The computational resources available in the ACL are ofmore » the type needed to solve problems critical to national needs, the so-called ``Grand Challenge`` problems. The purpose of this publication is to inform our clients of our strategic and operating plans in these important areas. We review major accomplishments since late 1990 and describe our strategic planning goals and specific projects that will guide our operations over the next few years. Our mission statement, planning considerations, and management policies and practices are also included.« less

Concepts for fast acquisition in optical communications systems

NASA Astrophysics Data System (ADS)

Wilkerson, Brandon L.; Giggenbach, Dirk; Epple, Bernhard

2006-09-01

As free-space laser communications systems proliferate due to improved technology and transmission techniques, optical communication networks comprised of ground stations, aircraft, high altitude platforms, and satellites become an attainable goal. An important consideration for optical networks is the ability of optical communication terminals (OCT) to quickly locate one another and align their laser beams to initiate the acquisition sequence. This paper investigates promising low-cost technologies and novel approaches that will facilitate the targeting and acquisition tasks between counter terminals. Specifically, two critical technology areas are investigated: position determination (which includes location and attitude determination) and inter-terminal communications. A feasibility study identified multiple-antenna global navigation satellite system (GNSS) systems and GNSS-aided inertial systems as possible position determination solutions. Personal satellite communication systems (e.g. Iridium or Inmarsat), third generation cellular technology (IMT-2000/UMTS), and a relatively new air traffic surveillance technology called Autonomous Dependent Surveillance-Broadcast (ADS-B) were identified as possible inter-terminal communication solutions. A GNSS-aided inertial system and an ADS-B system were integrated into an OCT to demonstrate their utility in a typical optical communication scenario. Testing showed that these technologies have high potential in future OCTs, although improvements can be made to both to increase tracking accuracy.

Experimental high-speed network

NASA Astrophysics Data System (ADS)

McNeill, Kevin M.; Klein, William P.; Vercillo, Richard; Alsafadi, Yasser H.; Parra, Miguel V.; Dallas, William J.

1993-09-01

Many existing local area networking protocols currently applied in medical imaging were originally designed for relatively low-speed, low-volume networking. These protocols utilize small packet sizes appropriate for text based communication. Local area networks of this type typically provide raw bandwidth under 125 MHz. These older network technologies are not optimized for the low delay, high data traffic environment of a totally digital radiology department. Some current implementations use point-to-point links when greater bandwidth is required. However, the use of point-to-point communications for a total digital radiology department network presents many disadvantages. This paper describes work on an experimental multi-access local area network called XFT. The work includes the protocol specification, and the design and implementation of network interface hardware and software. The protocol specifies the Physical and Data Link layers (OSI layers 1 & 2) for a fiber-optic based token ring providing a raw bandwidth of 500 MHz. The protocol design and implementation of the XFT interface hardware includes many features to optimize image transfer and provide flexibility for additional future enhancements which include: a modular hardware design supporting easy portability to a variety of host system buses, a versatile message buffer design providing 16 MB of memory, and the capability to extend the raw bandwidth of the network to 3.0 GHz.

A scaleable integrated sensing and control system for NDE, monitoring, and control of medium to very large composite smart structures

NASA Astrophysics Data System (ADS)

Jones, Jerry; Rhoades, Valerie; Arner, Radford; Clem, Timothy; Cuneo, Adam

2007-04-01

NDE measurements, monitoring, and control of smart and adaptive composite structures requires that the central knowledge system have an awareness of the entire structure. Achieving this goal necessitates the implementation of an integrated network of significant numbers of sensors. Additionally, in order to temporally coordinate the data from specially distributed sensors, the data must be time relevant. Early adoption precludes development of sensor technology specifically for this application, instead it will depend on the ability to utilize legacy systems. Partially supported by the U.S. Department of Commerce, National Institute of Standards and Technology, Advanced Technology Development Program (NIST-ATP), a scalable integrated system has been developed to implement monitoring of structural integrity and the control of adaptive/intelligent structures. The project, called SHIELD (Structural Health Identification and Electronic Life Determination), was jointly undertaken by: Caterpillar, N.A. Tech., Motorola, and Microstrain. SHIELD is capable of operation with composite structures, metallic structures, or hybrid structures. SHIELD consists of a real-time processing core on a Motorola MPC5200 using a C language based real-time operating system (RTOS). The RTOS kernel was customized to include a virtual backplane which makes the system completely scalable. This architecture provides for multiple processes to be operating simultaneously. They may be embedded as multiple threads on the core hardware or as separate independent processors connected to the core using a software driver called a NAT-Network Integrator (NATNI). NATNI's can be created for any communications application. In it's current embodiment, NATNI's have been created for CAN bus, TCP/IP (Ethernet) - both wired and 802.11 b and g, and serial communications using RS485 and RS232. Since SHIELD uses standard C language, it is easy to port any monitoring or control algorithm, thus providing for legacy technology which may use other hardware processors and various communications means. For example, two demonstrations of SHIELD have been completed, in January and May 2005 respectively. One demonstration used algorithms in C running in multiple threads in the SHIELD core and utilizing two different sensor networks, one CAN bus and one wireless. The second had algorithms operating in C on the SHIELD core and other algorithms running on multiple Texas Instruments DSP processors using a NATNI that communicated via wired TCP/IP. A key feature of SHIELD is the implementation of a wireless ZIGBEE (802.15.4) network for implementing large numbers of small, low cost, low power sensors communication via a meshstar wireless network. While SHIELD was designed to integrate with a wide variety of existing communications protocols, a ZIGBEE network capability was implemented specifically for SHIELD. This will facilitate the monitoring of medium to very large structures including marine applications, utility scale multi-megawatt wind energy systems, and aircraft/spacecraft. The SHIELD wireless network will facilitate large numbers of sensors (up to 32000), accommodate sensors embedded into the composite material, can communicate to both sensors and actuators, and prevents obsolescence by providing for re-programming of the nodes via remote RF communications. The wireless network provides for ultra-low energy use, spatial location, and accurate timestamping, utilizing the beaconing feature of ZIGBEE.

On Campus Benefits from an Innovative Extended Campus Library Services Program.

ERIC Educational Resources Information Center

Cookingham, Robert M.

Utilizing the experience of the library of California State University (CSU), Chico in servicing off-campus students who receive instruction via a two-way audio and one-way video communication network called the Instructional Television Fixed Service (ITFS), this paper examines the role that extended campus library services can play in the process…

CCML--Exchanging Marked-Up Documents in a Networked Writing Classroom.

ERIC Educational Resources Information Center

Ogata, Hiroaki; Yano, Yoneo; Wakita, Riko

1998-01-01

Describes an on-line mark-up-based composition learning environment system called CoCoA (Communicative Collection Assisting System). This system allows students and teachers to engage in marked-up documents via the Internet, and its environment is very similar to a real-world one in which people use pen and paper. CCML also facilitates teachers to…

77 FR 29529 - Peace Officers Memorial Day and Police Week, 2012

Federal Register 2010, 2011, 2012, 2013, 2014

2012-05-18

... sacrifices they may be called upon to make. This week, we pay tribute to the thousands of men and women who... communication network in times of crisis--helping fulfill our promise to provide these brave men and women with... those who devote their lives to forging a stronger, safer America. Let us reflect on their invaluable...

Scholastic Journalism Teacher Use of Digital Devices and Social Networking Tools in a Poor, Largely Rural State

ERIC Educational Resources Information Center

Plopper, Bruce L.; Conaway, Anne Fleming

2013-01-01

Research showing adolescents' ever-increasing use of digital devices, combined with calls from governmental officials to incorporate more technology into classroom activities, prompted this survey of Arkansas scholastic journalism advisers. The goal was to determine how they used digital communication devices in their teaching. Results showed lack…

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

NONE

Fieldbus technology has completed beta plant testing at Monsanto Co.`s Chocolate Bayou petrochemical complex at Alvin, Texas. The trial took place in a steam condensate recovery section of the Chocolate Bayou plant, which produces acrylonitrile, linear alkylbenzene, and a number of other petrochemical derivatives. Fieldbus is a plant communications network, or bus, that enables digital instruments to communicate with one another and with supervisory control systems. The fieldbus specification, written by the nonprofit organization Fieldbus Foundation, Austin, Texas, is called Foundation fieldbus. The beta tests at Chocolate Bayou successfully demonstrated fieldbus performance in a process control application.

Mandala Networks: ultra-small-world and highly sparse graphs

PubMed Central

Sampaio Filho, Cesar I. N.; Moreira, André A.; Andrade, Roberto F. S.; Herrmann, Hans J.; Andrade, José S.

2015-01-01

The increasing demands in security and reliability of infrastructures call for the optimal design of their embedded complex networks topologies. The following question then arises: what is the optimal layout to fulfill best all the demands? Here we present a general solution for this problem with scale-free networks, like the Internet and airline networks. Precisely, we disclose a way to systematically construct networks which are robust against random failures. Furthermore, as the size of the network increases, its shortest path becomes asymptotically invariant and the density of links goes to zero, making it ultra-small world and highly sparse, respectively. The first property is ideal for communication and navigation purposes, while the second is interesting economically. Finally, we show that some simple changes on the original network formulation can lead to an improved topology against malicious attacks. PMID:25765450

GSM-Railway as part of the European Rail Traffic Management System

NASA Astrophysics Data System (ADS)

Bibac, Ionut

2007-05-01

GSM-R is a vital component inside the ERTMS which is also an essential element of European Community rail projects; investment in equipping and the rolling stock with ERTMS could reach 5 billion eurodollars in the period 2007-2016. GSM-R is the result of over ten years of collaboration between the various European railway companies, the railway communication industry and the different standardization bodies. GSM-R provides a secure platform for voice and data communication between the operational staff of the railway companies including drivers, dispatchers, shunting team members, train engineers, and station controllers. It delivers advanced features such as group calls, voice broadcast, location based connections, and call pre-emption in case of an emergency, which significantly improves communication, collaboration, and security management across operational staff members. Taking into account the above mentioned, the paper will permit to audience to discover the GSM-R network architecture, services and applications proposed by this technology together with the future development and market situation due to the market liberalization.

Time Synchronization Prototype, Server Upgrade Procedure Support and Remote Software Development

NASA Technical Reports Server (NTRS)

Sanders, Shania R.

2014-01-01

Networks are roadways of communication that connect devices. Like all roadways, there are rules and regulations that govern whatever (information in this case) travels along them. One type of rule that is commonly used is called a protocol. More specifically, a protocol is a standard that specifies how data should be transmitted over a network. The project outlined in this document seeks to implement one protocol in particular, Precision Time Protocol, within the Kennedy Ground Control Subsystem network at Kennedy Space Center. This document also summarizes work completed for server upgrades, remote software developer training and how all three assignments demonstrated the importance of accountability and security.

Inferring social status and rich club effects in enterprise communication networks.

PubMed

Dong, Yuxiao; Tang, Jie; Chawla, Nitesh V; Lou, Tiancheng; Yang, Yang; Wang, Bai

2015-01-01

Social status, defined as the relative rank or position that an individual holds in a social hierarchy, is known to be among the most important motivating forces in social behaviors. In this paper, we consider the notion of status from the perspective of a position or title held by a person in an enterprise. We study the intersection of social status and social networks in an enterprise. We study whether enterprise communication logs can help reveal how social interactions and individual status manifest themselves in social networks. To that end, we use two enterprise datasets with three communication channels--voice call, short message, and email--to demonstrate the social-behavioral differences among individuals with different status. We have several interesting findings and based on these findings we also develop a model to predict social status. On the individual level, high-status individuals are more likely to be spanned as structural holes by linking to people in parts of the enterprise networks that are otherwise not well connected to one another. On the community level, the principle of homophily, social balance and clique theory generally indicate a "rich club" maintained by high-status individuals, in the sense that this community is much more connected, balanced and dense. Our model can predict social status of individuals with 93% accuracy.

A Hop-Sensitive Mechanism to Establish Route Optimization in Mobile Networks

NASA Astrophysics Data System (ADS)

Gnanaraj, J. Isac; Newton, P. Calduwel; Arockiam, L.; Kim, Tai-Hoon

The mobile network plays a vital role in mobile communications. It supports both host mobility and network mobility. The mobile network which supports network mobility can be called as NEMO. The NEMO refers to NEtwork MObility or mobile network that moves. Though NEMO provides many supports, it also suffers due to Quality of Service (QoS) issues. One such issue is Route Optimization (RO). When a Mobile Node (MN) is away from Home Network (HN), it will send a binding update to Home Agent (HA) in HN to inform its movement. If the Correspondent Node (CN) wants to send data to MN, it will send data through HA. In this scenario, three networks such as HN, Foreign Network (FN) and Correspondent Network are involved in data transfer. The involvement of these three networks affects the QoS. This paper concentrates on some of the QoS parameters to propose a QoS mechanism to establish RO among these three networks and significantly increases performance of the mobile network.

Cyber Security Vulnerabilities During Long Term Evolution Power-Saving Discontinuous Reception Protocol

DTIC Science & Technology

2014-06-01

2G second generation 3G third generation 3GPP Third Generation Partnership Project 4G fourth generation AAA authentication, authorization and...RRC_IDLE or the RRC_CONNECTED states in 4G LTE as shown in Figure 19. 2G and 3G networks use DRX in idle mode only. In Figure 19, LTE-U_u is the new DRX...is a wireless access communications network that consists of base stations called eNodeBs (eNBs), which allow connectivity between the mobile device

Evolution of the Lunar Network

NASA Technical Reports Server (NTRS)

Gal-Edd, Jonathan; Fatig, Curtis C.; Miller, Ron

2008-01-01

The National Aeronautics and Space Administration (NASA) is planning to upgrade its network Infrastructure to support missions for the 21st century. The first step is to increase the data rate provided to science missions to at least the 100 megabits per second (Mbps) range. This is under way, using Ka-band 26 Gigahertz (GHz), erecting an 18-meter antenna for the Lunar Reconnaissance Orbiter (LRO), and the planned upgrade of the Deep Space Network (DSN) 34-meter network to support the James Webb Space Telescope (JWST). The next step is the support of manned missions to the Moon and beyond. Establishing an outpost with several activities such as rovers, colonization, and observatories, is better achieved by using a network configuration rather than the current method of point-to-point communication. Another challenge associated with the Moon is communication coverage with the Earth. The Moon's South Pole, targeted for human habitat and exploration, is obscured from Earth view for half of the 28-day lunar cycle and requires the use of lunar relay satellites to provide coverage when there is no direct view of the Earth. The future NASA and Constellation network architecture is described in the Space Communications Architecture Working Group (SCAWG) Report. The Space Communications and Navigation (SCAN) Constellation Integration Project (SCIP) is responsible for coordinating Constellation requirements and has assigned the responsibility for implementing these requirements to the existing NASA communication providers: DSN, Space Network (SN), Ground Network (GN) and the NASA Integrated Services Network (NISN). The SCAWG Report provides a future architecture but does not provide implementation details. The architecture calls for a Netcentric system, using hundreds of 12-meter antennas, a ground antenna array, and a relay network around the Moon. The report did not use cost as a variable in determining the feasibility of this approach. As part of the SCIP Mission Concept Review and the second iteration of the Lunar Architecture Team (LAT), the focus is on cost, as well as communication coverage using operational scenarios. This approach maximizes use of existing assets and adds capability in small increments. This paper addresses architecture decisions such as the Radio Frequency (RF) signal and network (Netcentric) decisions that need to be made and the difficulty of implementing them into the existing Space Network and DSN. It discusses the evolution of the lunar system and describes its components: Tracking and Data Relay Satellite System (TDRSS), Earth-based ground stations, Lunar Relay, and surface systems.

A call for innovative social media research in the field of augmentative and alternative communication.

PubMed

Hemsley, Bronwyn; Balandin, Susan; Palmer, Stuart; Dann, Stephen

2017-03-01

Augmentative and alternative communication (AAC) social media research is relatively new, and is built on a foundation of research on use of the Internet and social media by people with communication disabilities. Although the field is expanding to include a range of people who use AAC, there are limitations and gaps in research that will need to be addressed in order to keep pace with the rapid evolution of social media connectivity in assistive communication technologies. In this paper, we consider the aims, scope, and methodologies of AAC social media research, with a focus on social network sites. Lack of detailed attention to specific social network sites and little use of social media data limits the extent to which findings can be confirmed. Increased use of social media data across a range of platforms, including Instagram and YouTube, would provide important insights into the lives of people who use AAC and the ways in which they and their supporters use social media. New directions for AAC social media research are presented in line with those discussed at the social media research symposium at the International Society for Augmentative and Alternative Communication in Toronto, Canada, on August 12, 2016.

Statistical Mechanics of Temporal and Interacting Networks

NASA Astrophysics Data System (ADS)

Zhao, Kun

In the last ten years important breakthroughs in the understanding of the topology of complexity have been made in the framework of network science. Indeed it has been found that many networks belong to the universality classes called small-world networks or scale-free networks. Moreover it was found that the complex architecture of real world networks strongly affects the critical phenomena defined on these structures. Nevertheless the main focus of the research has been the characterization of single and static networks. Recently, temporal networks and interacting networks have attracted large interest. Indeed many networks are interacting or formed by a multilayer structure. Example of these networks are found in social networks where an individual might be at the same time part of different social networks, in economic and financial networks, in physiology or in infrastructure systems. Moreover, many networks are temporal, i.e. the links appear and disappear on the fast time scale. Examples of these networks are social networks of contacts such as face-to-face interactions or mobile-phone communication, the time-dependent correlations in the brain activity and etc. Understanding the evolution of temporal and multilayer networks and characterizing critical phenomena in these systems is crucial if we want to describe, predict and control the dynamics of complex system. In this thesis, we investigate several statistical mechanics models of temporal and interacting networks, to shed light on the dynamics of this new generation of complex networks. First, we investigate a model of temporal social networks aimed at characterizing human social interactions such as face-to-face interactions and phone-call communication. Indeed thanks to the availability of data on these interactions, we are now in the position to compare the proposed model to the real data finding good agreement. Second, we investigate the entropy of temporal networks and growing networks , to provide a new framework to quantify the information encoded in these networks and to answer a fundamental problem in network science: how complex are temporal and growing networks. Finally, we consider two examples of critical phenomena in interacting networks. In particular, on one side we investigate the percolation of interacting networks by introducing antagonistic interactions. On the other side, we investigate a model of political election based on the percolation of antagonistic networks. The aim of this research is to show how antagonistic interactions change the physics of critical phenomena on interacting networks. We believe that the work presented in these thesis offers the possibility to appreciate the large variability of problems that can be addressed in the new framework of temporal and interacting networks.

Dynamic Resource Adjustment to Provide Seamless Streaming Services on Multimedia Mobile Cellular Networks

NASA Astrophysics Data System (ADS)

Lin, Chow-Sing; Yen, Fang-Zhi

With the rapid advances in wireless network communication, multimedia presentation has become more applicable. However, due to the limited wireless network resource and the mobility of Mobile Host (MH), QoS for wireless streaming is much more difficult to maintain. How to decrease Call Dropping Probability (CDP) in multimedia traffic while still keeping acceptable Call Block Probability (CBP) without sacrificing QoS has become an significant issue in providing wireless streaming services. In this paper, we propose a novel Dynamic Resources Adjustment (DRA) algorithm, which can dynamically borrow idle reserved resources in the serving cell or the target cell for handoffing MHs to compensate the shortage of bandwidth in media streaming. The experimental simulation results show that compared with traditional No Reservation (NR), and Resource Reservation in the six neighboring cells (RR-nb), and Resource Reservation in the target cell (RR-t), our proposed DRA algorithm can fully utilize unused reserved resources to effectively decrease the CDP while still keeping acceptable CBP with high bandwidth utilization.

Traffic sharing algorithms for hybrid mobile networks

NASA Technical Reports Server (NTRS)

Arcand, S.; Murthy, K. M. S.; Hafez, R.

1995-01-01

In a hybrid (terrestrial + satellite) mobile personal communications networks environment, a large size satellite footprint (supercell) overlays on a large number of smaller size, contiguous terrestrial cells. We assume that the users have either a terrestrial only single mode terminal (SMT) or a terrestrial/satellite dual mode terminal (DMT) and the ratio of DMT to the total terminals is defined gamma. It is assumed that the call assignments to and handovers between terrestrial cells and satellite supercells take place in a dynamic fashion when necessary. The objectives of this paper are twofold, (1) to propose and define a class of traffic sharing algorithms to manage terrestrial and satellite network resources efficiently by handling call handovers dynamically, and (2) to analyze and evaluate the algorithms by maximizing the traffic load handling capability (defined in erl/cell) over a wide range of terminal ratios (gamma) given an acceptable range of blocking probabilities. Two of the algorithms (G & S) in the proposed class perform extremely well for a wide range of gamma.

Human initiated cascading failures in societal infrastructures.

PubMed

Barrett, Chris; Channakeshava, Karthik; Huang, Fei; Kim, Junwhan; Marathe, Achla; Marathe, Madhav V; Pei, Guanhong; Saha, Sudip; Subbiah, Balaaji S P; Vullikanti, Anil Kumar S

2012-01-01

In this paper, we conduct a systematic study of human-initiated cascading failures in three critical inter-dependent societal infrastructures due to behavioral adaptations in response to a crisis. We focus on three closely coupled socio-technical networks here: (i) cellular and mesh networks, (ii) transportation networks and (iii) mobile call networks. In crises, changes in individual behaviors lead to altered travel, activity and calling patterns, which influence the transport network and the loads on wireless networks. The interaction between these systems and their co-evolution poses significant technical challenges for representing and reasoning about these systems. In contrast to system dynamics models for studying these interacting infrastructures, we develop interaction-based models in which individuals and infrastructure elements are represented in detail and are placed in a common geographic coordinate system. Using the detailed representation, we study the impact of a chemical plume that has been released in a densely populated urban region. Authorities order evacuation of the affected area, and this leads to individual behavioral adaptation wherein individuals drop their scheduled activities and drive to home or pre-specified evacuation shelters as appropriate. They also revise their calling behavior to communicate and coordinate among family members. These two behavioral adaptations cause flash-congestion in the urban transport network and the wireless network. The problem is exacerbated with a few, already occurring, road closures. We analyze how extended periods of unanticipated road congestion can result in failure of infrastructures, starting with the servicing base stations in the congested area. A sensitivity analysis on the compliance rate of evacuees shows non-intuitive effect on the spatial distribution of people and on the loading of the base stations. For example, an evacuation compliance rate of 70% results in higher number of overloaded base stations than the evacuation compliance rate of 90%.

Human Initiated Cascading Failures in Societal Infrastructures

PubMed Central

Barrett, Chris; Channakeshava, Karthik; Huang, Fei; Kim, Junwhan; Marathe, Achla; Marathe, Madhav V.; Pei, Guanhong; Saha, Sudip; Subbiah, Balaaji S. P.; Vullikanti, Anil Kumar S.

2012-01-01

In this paper, we conduct a systematic study of human-initiated cascading failures in three critical inter-dependent societal infrastructures due to behavioral adaptations in response to a crisis. We focus on three closely coupled socio-technical networks here: (i) cellular and mesh networks, (ii) transportation networks and (iii) mobile call networks. In crises, changes in individual behaviors lead to altered travel, activity and calling patterns, which influence the transport network and the loads on wireless networks. The interaction between these systems and their co-evolution poses significant technical challenges for representing and reasoning about these systems. In contrast to system dynamics models for studying these interacting infrastructures, we develop interaction-based models in which individuals and infrastructure elements are represented in detail and are placed in a common geographic coordinate system. Using the detailed representation, we study the impact of a chemical plume that has been released in a densely populated urban region. Authorities order evacuation of the affected area, and this leads to individual behavioral adaptation wherein individuals drop their scheduled activities and drive to home or pre-specified evacuation shelters as appropriate. They also revise their calling behavior to communicate and coordinate among family members. These two behavioral adaptations cause flash-congestion in the urban transport network and the wireless network. The problem is exacerbated with a few, already occurring, road closures. We analyze how extended periods of unanticipated road congestion can result in failure of infrastructures, starting with the servicing base stations in the congested area. A sensitivity analysis on the compliance rate of evacuees shows non-intuitive effect on the spatial distribution of people and on the loading of the base stations. For example, an evacuation compliance rate of 70% results in higher number of overloaded base stations than the evacuation compliance rate of 90%. PMID:23118847

A New Random Walk for Replica Detection in WSNs.

PubMed

Aalsalem, Mohammed Y; Khan, Wazir Zada; Saad, N M; Hossain, Md Shohrab; Atiquzzaman, Mohammed; Khan, Muhammad Khurram

2016-01-01

Wireless Sensor Networks (WSNs) are vulnerable to Node Replication attacks or Clone attacks. Among all the existing clone detection protocols in WSNs, RAWL shows the most promising results by employing Simple Random Walk (SRW). More recently, RAND outperforms RAWL by incorporating Network Division with SRW. Both RAND and RAWL have used SRW for random selection of witness nodes which is problematic because of frequently revisiting the previously passed nodes that leads to longer delays, high expenditures of energy with lower probability that witness nodes intersect. To circumvent this problem, we propose to employ a new kind of constrained random walk, namely Single Stage Memory Random Walk and present a distributed technique called SSRWND (Single Stage Memory Random Walk with Network Division). In SSRWND, single stage memory random walk is combined with network division aiming to decrease the communication and memory costs while keeping the detection probability higher. Through intensive simulations it is verified that SSRWND guarantees higher witness node security with moderate communication and memory overheads. SSRWND is expedient for security oriented application fields of WSNs like military and medical.

A New Random Walk for Replica Detection in WSNs

PubMed Central

Aalsalem, Mohammed Y.; Saad, N. M.; Hossain, Md. Shohrab; Atiquzzaman, Mohammed; Khan, Muhammad Khurram

2016-01-01

Wireless Sensor Networks (WSNs) are vulnerable to Node Replication attacks or Clone attacks. Among all the existing clone detection protocols in WSNs, RAWL shows the most promising results by employing Simple Random Walk (SRW). More recently, RAND outperforms RAWL by incorporating Network Division with SRW. Both RAND and RAWL have used SRW for random selection of witness nodes which is problematic because of frequently revisiting the previously passed nodes that leads to longer delays, high expenditures of energy with lower probability that witness nodes intersect. To circumvent this problem, we propose to employ a new kind of constrained random walk, namely Single Stage Memory Random Walk and present a distributed technique called SSRWND (Single Stage Memory Random Walk with Network Division). In SSRWND, single stage memory random walk is combined with network division aiming to decrease the communication and memory costs while keeping the detection probability higher. Through intensive simulations it is verified that SSRWND guarantees higher witness node security with moderate communication and memory overheads. SSRWND is expedient for security oriented application fields of WSNs like military and medical. PMID:27409082

Application of high performance asynchronous socket communication in power distribution automation

NASA Astrophysics Data System (ADS)

Wang, Ziyu

2017-05-01

With the development of information technology and Internet technology, and the growing demand for electricity, the stability and the reliable operation of power system have been the goal of power grid workers. With the advent of the era of big data, the power data will gradually become an important breakthrough to guarantee the safe and reliable operation of the power grid. So, in the electric power industry, how to efficiently and robustly receive the data transmitted by the data acquisition device, make the power distribution automation system be able to execute scientific decision quickly, which is the pursuit direction in power grid. In this paper, some existing problems in the power system communication are analysed, and with the help of the network technology, a set of solutions called Asynchronous Socket Technology to the problem in network communication which meets the high concurrency and the high throughput is proposed. Besides, the paper also looks forward to the development direction of power distribution automation in the era of big data and artificial intelligence.

Fortified Anonymous Communication Protocol for Location Privacy in WSN: A Modular Approach

PubMed Central

Abuzneid, Abdel-Shakour; Sobh, Tarek; Faezipour, Miad; Mahmood, Ausif; James, John

2015-01-01

Wireless sensor network (WSN) consists of many hosts called sensors. These sensors can sense a phenomenon (motion, temperature, humidity, average, max, min, etc.) and represent what they sense in a form of data. There are many applications for WSNs including object tracking and monitoring where in most of the cases these objects need protection. In these applications, data privacy itself might not be as important as the privacy of source location. In addition to the source location privacy, sink location privacy should also be provided. Providing an efficient end-to-end privacy solution would be a challenging task to achieve due to the open nature of the WSN. The key schemes needed for end-to-end location privacy are anonymity, observability, capture likelihood, and safety period. We extend this work to allow for countermeasures against multi-local and global adversaries. We present a network model protected against a sophisticated threat model: passive /active and local/multi-local/global attacks. This work provides a solution for end-to-end anonymity and location privacy as well. We will introduce a framework called fortified anonymous communication (FAC) protocol for WSN. PMID:25763649

Design and Implementation of Replicated Object Layer

NASA Technical Reports Server (NTRS)

Koka, Sudhir

1996-01-01

One of the widely used techniques for construction of fault tolerant applications is the replication of resources so that if one copy fails sufficient copies may still remain operational to allow the application to continue to function. This thesis involves the design and implementation of an object oriented framework for replicating data on multiple sites and across different platforms. Our approach, called the Replicated Object Layer (ROL) provides a mechanism for consistent replication of data over dynamic networks. ROL uses the Reliable Multicast Protocol (RMP) as a communication protocol that provides for reliable delivery, serialization and fault tolerance. Besides providing type registration, this layer facilitates distributed atomic transactions on replicated data. A novel algorithm called the RMP Commit Protocol, which commits transactions efficiently in reliable multicast environment is presented. ROL provides recovery procedures to ensure that site and communication failures do not corrupt persistent data, and male the system fault tolerant to network partitions. ROL will facilitate building distributed fault tolerant applications by performing the burdensome details of replica consistency operations, and making it completely transparent to the application.Replicated databases are a major class of applications which could be built on top of ROL.

Management software for a universal device communication controller: application to monitoring and computerized infusions.

PubMed

Coussaert, E J; Cantraine, F R

1996-11-01

We designed a virtual device for a local area network observing, operating and connecting devices to a personal computer. To keep the widest field of application, we proceeded by using abstraction and specification rules of software engineering in the design and implementation of the hardware and software for the Infusion Monitor. We specially built a box of hardware to interface multiple medical instruments with different communication protocols to a PC via a single serial port. We called that box the Universal Device Communication Controller (UDCC). The use of the virtual device driver is illustrated by the Infusion Monitor implemented for the anaesthesia and intensive care workstation.

Collective iteration behavior for online social networks

NASA Astrophysics Data System (ADS)

Liu, Jian-Guo; Li, Ren-De; Guo, Qiang; Zhang, Yi-Cheng

2018-06-01

Understanding the patterns of collective behavior in online social network (OSNs) is critical to expanding the knowledge of human behavior and tie relationship. In this paper, we investigate a specific pattern called social signature in Facebook and Wiki users' online communication behaviors, capturing the distribution of frequency of interactions between different alters over time in the ego network. The empirical results show that there are robust social signatures of interactions no matter how friends change over time, which indicates that a stable commutation pattern exists in online communication. By comparing a random null model, we find the that commutation pattern is heterogeneous between ego and alters. Furthermore, in order to regenerate the pattern of the social signature, we present a preferential interaction model, which assumes that new users intend to look for the old users with strong ties while old users have tendency to interact with new friends. The experimental results show that the presented model can reproduce the heterogeneity of social signature by adjusting 2 parameters, the number of communicating targets m and the max number of interactions n, for Facebook users, m = n = 5, for Wiki users, m = 2 and n = 8. This work helps in deeply understanding the regularity of social signature.

An OFDM Receiver with Frequency Domain Diversity Combined Impulsive Noise Canceller for Underwater Network.

PubMed

Saotome, Rie; Hai, Tran Minh; Matsuda, Yasuto; Suzuki, Taisaku; Wada, Tomohisa

2015-01-01

In order to explore marine natural resources using remote robotic sensor or to enable rapid information exchange between ROV (remotely operated vehicles), AUV (autonomous underwater vehicle), divers, and ships, ultrasonic underwater communication systems are used. However, if the communication system is applied to rich living creature marine environment such as shallow sea, it suffers from generated Impulsive Noise so-called Shrimp Noise, which is randomly generated in time domain and seriously degrades communication performance in underwater acoustic network. With the purpose of supporting high performance underwater communication, a robust digital communication method for Impulsive Noise environments is necessary. In this paper, we propose OFDM ultrasonic communication system with diversity receiver. The main feature of the receiver is a newly proposed Frequency Domain Diversity Combined Impulsive Noise Canceller. The OFDM receiver utilizes 20-28 KHz ultrasonic channel and subcarrier spacing of 46.875 Hz (MODE3) and 93.750 Hz (MODE2) OFDM modulations. In addition, the paper shows Impulsive Noise distribution data measured at a fishing port in Okinawa and at a barge in Shizuoka prefectures and then proposed diversity OFDM transceivers architecture and experimental results are described. By the proposed Impulsive Noise Canceller, frame bit error rate has been decreased by 20-30%.

Evaluating System Parameters on a Dragonfly using Simulation and Visualization

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

Bhatele, Abhinav; Jain, Nikhil; Livnat, Yarden

The dragon y topology is becoming a popular choice for build- ing high-radix, low-diameter networks with high-bandwidth links. Even with a powerful network, preliminary experi- ments on Edison at NERSC have shown that for communica- tion heavy applications, job interference and thus presumably job placement remains an important factor. In this paper, we explore the e ects of job placement, job sizes, parallel workloads and network con gurations on network through- put to better understand inter-job interference. We use a simulation tool called Damsel y to model the network be- havior of Edison and study the impact of various systemmore » parameters on network throughput. Parallel workloads based on ve representative communication patters are used and the simulation studies on up to 131,072 cores are aided by a new visualization of the dragon y network.« less

Space Link Extension Protocol Emulation for High-Throughput, High-Latency Network Connections

NASA Technical Reports Server (NTRS)

Tchorowski, Nicole; Murawski, Robert

2014-01-01

New space missions require higher data rates and new protocols to meet these requirements. These high data rate space communication links push the limitations of not only the space communication links, but of the ground communication networks and protocols which forward user data to remote ground stations (GS) for transmission. The Consultative Committee for Space Data Systems, (CCSDS) Space Link Extension (SLE) standard protocol is one protocol that has been proposed for use by the NASA Space Network (SN) Ground Segment Sustainment (SGSS) program. New protocol implementations must be carefully tested to ensure that they provide the required functionality, especially because of the remote nature of spacecraft. The SLE protocol standard has been tested in the NASA Glenn Research Center's SCENIC Emulation Lab in order to observe its operation under realistic network delay conditions. More specifically, the delay between then NASA Integrated Services Network (NISN) and spacecraft has been emulated. The round trip time (RTT) delay for the continental NISN network has been shown to be up to 120ms; as such the SLE protocol was tested with network delays ranging from 0ms to 200ms. Both a base network condition and an SLE connection were tested with these RTT delays, and the reaction of both network tests to the delay conditions were recorded. Throughput for both of these links was set at 1.2Gbps. The results will show that, in the presence of realistic network delay, the SLE link throughput is significantly reduced while the base network throughput however remained at the 1.2Gbps specification. The decrease in SLE throughput has been attributed to the implementation's use of blocking calls. The decrease in throughput is not acceptable for high data rate links, as the link requires constant data a flow in order for spacecraft and ground radios to stay synchronized, unless significant data is queued a the ground station. In cases where queuing the data is not an option, such as during real time transmissions, the SLE implementation cannot support high data rate communication.

On the improvement of neural cryptography using erroneous transmitted information with error prediction.

PubMed

Allam, Ahmed M; Abbas, Hazem M

2010-12-01

Neural cryptography deals with the problem of "key exchange" between two neural networks using the mutual learning concept. The two networks exchange their outputs (in bits) and the key between the two communicating parties is eventually represented in the final learned weights, when the two networks are said to be synchronized. Security of neural synchronization is put at risk if an attacker is capable of synchronizing with any of the two parties during the training process. Therefore, diminishing the probability of such a threat improves the reliability of exchanging the output bits through a public channel. The synchronization with feedback algorithm is one of the existing algorithms that enhances the security of neural cryptography. This paper proposes three new algorithms to enhance the mutual learning process. They mainly depend on disrupting the attacker confidence in the exchanged outputs and input patterns during training. The first algorithm is called "Do not Trust My Partner" (DTMP), which relies on one party sending erroneous output bits, with the other party being capable of predicting and correcting this error. The second algorithm is called "Synchronization with Common Secret Feedback" (SCSFB), where inputs are kept partially secret and the attacker has to train its network on input patterns that are different from the training sets used by the communicating parties. The third algorithm is a hybrid technique combining the features of the DTMP and SCSFB. The proposed approaches are shown to outperform the synchronization with feedback algorithm in the time needed for the parties to synchronize.

Saving energy for the data collection point in WBAN network

NASA Astrophysics Data System (ADS)

Nguyen-Duc, Toan; Kamioka, Eiji

2017-11-01

Wireless sensor networking (WSN) has been rapidly developed and become essential in various domains including health care systems. Such systems use WSN to collect real-time medical sensed data, aiming at improving the patient safety. For instance, patients suffered from adverse events, i.e., cardiac or respiratory arrests, are monitored so as to prevent them from getting harm. Sensors are placed on, in or near the patients' body to continuously collect sensing data such as the electrocardiograms, blood oxygenation, breathing, and heart rate. In this case, the sensors form a subcategory of WSN called wireless body area network (WBAN). In WBAN, sensing data are sent to one or more data collection points called personal server (PS). The role of PS is important since it forwards sensed data, to a medical server via a Bluetooth/WLAN connection in real time to support storage of information and real-time diagnosis, the device can also issue a notification of an emergency status. Since PS is a battery-based device, when its battery is empty, it will disconnect the sensed medical data with the rest network. To best of our knowledge, very few studies that focus on saving energy for the PS. To this end, this work investigates the trade-off between energy consumption for wireless communication and the amount of sensing data. An energy consumption model for wireless communication has been proposed based on direct measurement using real testbed. According to our findings, it is possible to save energy for the PS by selecting suitable wireless technology to be used based on the amount of data to be transmitted.

Autosophy information theory provides lossless data and video compression based on the data content

NASA Astrophysics Data System (ADS)

Holtz, Klaus E.; Holtz, Eric S.; Holtz, Diana

1996-09-01

A new autosophy information theory provides an alternative to the classical Shannon information theory. Using the new theory in communication networks provides both a high degree of lossless compression and virtually unbreakable encryption codes for network security. The bandwidth in a conventional Shannon communication is determined only by the data volume and the hardware parameters, such as image size; resolution; or frame rates in television. The data content, or what is shown on the screen, is irrelevant. In contrast, the bandwidth in autosophy communication is determined only by data content, such as novelty and movement in television images. It is the data volume and hardware parameters that become irrelevant. Basically, the new communication methods use prior 'knowledge' of the data, stored in a library, to encode subsequent transmissions. The more 'knowledge' stored in the libraries, the higher the potential compression ratio. 'Information' is redefined as that which is not already known by the receiver. Everything already known is redundant and need not be re-transmitted. In a perfect communication each transmission code, called a 'tip,' creates a new 'engram' of knowledge in the library in which each tip transmission can represent any amount of data. Autosophy theories provide six separate learning modes, or omni dimensional networks, all of which can be used for data compression. The new information theory reveals the theoretical flaws of other data compression methods, including: the Huffman; Ziv Lempel; LZW codes and commercial compression codes such as V.42bis and MPEG-2.

The effect of various parameters of large scale radio propagation models on improving performance mobile communications

NASA Astrophysics Data System (ADS)

Pinem, M.; Fauzi, R.

2018-02-01

One technique for ensuring continuity of wireless communication services and keeping a smooth transition on mobile communication networks is the soft handover technique. In the Soft Handover (SHO) technique the inclusion and reduction of Base Station from the set of active sets is determined by initiation triggers. One of the initiation triggers is based on the strong reception signal. In this paper we observed the influence of parameters of large-scale radio propagation models to improve the performance of mobile communications. The observation parameters for characterizing the performance of the specified mobile system are Drop Call, Radio Link Degradation Rate and Average Size of Active Set (AS). The simulated results show that the increase in altitude of Base Station (BS) Antenna and Mobile Station (MS) Antenna contributes to the improvement of signal power reception level so as to improve Radio Link quality and increase the average size of Active Set and reduce the average Drop Call rate. It was also found that Hata’s propagation model contributed significantly to improvements in system performance parameters compared to Okumura’s propagation model and Lee’s propagation model.

Intrusion-Tolerant Location Information Services in Intelligent Vehicular Networks

NASA Astrophysics Data System (ADS)

Yan, Gongjun; Yang, Weiming; Shaner, Earl F.; Rawat, Danda B.

Intelligent Vehicular Networks, known as Vehicle-to-Vehicle and Vehicle-to-Roadside wireless communications (also called Vehicular Ad hoc Networks), are revolutionizing our daily driving with better safety and more infortainment. Most, if not all, applications will depend on accurate location information. Thus, it is of importance to provide intrusion-tolerant location information services. In this paper, we describe an adaptive algorithm that detects and filters the false location information injected by intruders. Given a noisy environment of mobile vehicles, the algorithm estimates the high resolution location of a vehicle by refining low resolution location input. We also investigate results of simulations and evaluate the quality of the intrusion-tolerant location service.

[Social network analysis: a method to improve safety in healthcare organizations].

PubMed

Marqués Sánchez, Pilar; González Pérez, Marta Eva; Agra Varela, Yolanda; Vega Núñez, Jorge; Pinto Carral, Arrate; Quiroga Sánchez, Enedina

2013-01-01

Patient safety depends on the culture of the healthcare organization involving relationships between professionals. This article proposes that the study of these relations should be conducted from a network perspective and using a methodology called Social Network Analysis (SNA). This methodology includes a set of mathematical constructs grounded in Graph Theory. With the SNA we can know aspects of the individual's position in the network (centrality) or cohesion among team members. Thus, the SNA allows to know aspects related to security such as the kind of links that can increase commitment among professionals, how to build those links, which nodes have more prestige in the team in generating confidence or collaborative network, which professionals serve as intermediaries between the subgroups of a team to transmit information or smooth conflicts, etc. Useful aspects in stablishing a safety culture. The SNA would analyze the relations among professionals, their level of communication to communicate errors and spontaneously seek help and coordination between departments to participate in projects that enhance safety. Thus, they related through a network, using the same language, a fact that helps to build a culture. In summary, we propose an approach to safety culture from a SNA perspective that would complement other commonly used methods.

Unpredictability and the transmission of numbers

NASA Astrophysics Data System (ADS)

Myers, John M.; Madjid, F. Hadi

2016-03-01

Curiously overlooked in physics is its dependence on the transmission of numbers. For example, the transmission of numerical clock readings is implicit in the concept of a coordinate system. The transmission of numbers and other logical distinctions is often achieved over a computer-mediated communications network in the face of an unpredictable environment. By unpredictable we mean something stronger than the spread of probabilities over given possible outcomes, namely an opening to unforeseeable possibilities. Unpredictability, until now overlooked in theoretical physics, makes the transmission of numbers interesting. Based on recent proofs within quantum theory that provide a theoretical foundation to unpredictability, here we show how regularities in physics rest on a background of channels over which numbers are transmitted. As is known to engineers of digital communications, numerical transmissions depend on coordination reminiscent of the cycle of throwing and catching by players tossing a ball back and forth. In digital communications, the players are computers, and the required coordination involves unpredictably adjusting "live clocks" that step these computers through phases of a cycle. We show how this phasing, which we call logical synchronization, constrains number-carrying networks, and, if a spacetime manifold in invoked, put "stripes" on spacetime. Via its logically synchronized channels, a network of live clocks serves as a reference against which to locate events. Such a network in any case underpins a coordinate frame, and in some cases the direct use of a network can be tailored to investigate an unpredictable environment. Examples include explorations of gravitational variations near Earth.

Design and Implementation of Davis Social Links OSN Kernel

NASA Astrophysics Data System (ADS)

Tran, Thomas; Chan, Kelcey; Ye, Shaozhi; Bhattacharyya, Prantik; Garg, Ankush; Lu, Xiaoming; Wu, S. Felix

Social network popularity continues to rise as they broaden out to more users. Hidden away within these social networks is a valuable set of data that outlines everyone’s relationships. Networks have created APIs such as the Facebook Development Platform and OpenSocial that allow developers to create applications that can leverage user information. However, at the current stage, the social network support for these new applications is fairly limited in its functionality. Most, if not all, of the existing internet applications such as email, BitTorrent, and Skype cannot benefit from the valuable social network among their own users. In this paper, we present an architecture that couples two different communication layers together: the end2end communication layer and the social context layer, under the Davis Social Links (DSL) project. Our proposed architecture attempts to preserve the original application semantics (i.e., we can use Thunderbird or Outlook, unmodified, to read our SMTP emails) and provides the communicating parties (email sender and receivers) a social context for control and management. For instance, the receiver can set trust policy rules based on the social context between the pair, to determine how a particular email in question should be prioritized for delivery to the SMTP layer. Furthermore, as our architecture includes two coupling layers, it is then possible, as an option, to shift some of the services from the original applications into the social context layer. In the context of email, for example, our architecture allows users to choose operations, such as reply, reply-all, and forward, to be realized in either the application layer or the social network layer. And, the realization of these operations under the social network layer offers powerful features unavailable in the original applications. To validate our coupling architecture, we have implemented a DSL kernel prototype as a Facebook application called CyrusDSL (currently about 40 local users) and a simple communication application combined into the DSL kernel but is unaware of Facebook’s API.

Virtual management of radiology examinations in the virtual radiology environment using common object request broker architecture services.

PubMed

Martinez, R; Rozenblit, J; Cook, J F; Chacko, A K; Timboe, H L

1999-05-01

In the Department of Defense (DoD), US Army Medical Command is now embarking on an extremely exciting new project--creating a virtual radiology environment (VRE) for the management of radiology examinations. The business of radiology in the military is therefore being reengineered on several fronts by the VRE Project. In the VRE Project, a set of intelligent agent algorithms determine where examinations are to routed for reading bases on a knowledge base of the entire VRE. The set of algorithms, called the Meta-Manager, is hierarchical and uses object-based communications between medical treatment facilities (MTFs) and medical centers that have digital imaging network picture archiving and communications systems (DIN-PACS) networks. The communications is based on use of common object request broker architecture (CORBA) objects and services to send patient demographics and examination images from DIN-PACS networks in the MTFs to the DIN-PACS networks at the medical centers for diagnosis. The Meta-Manager is also responsible for updating the diagnosis at the originating MTF. CORBA services are used to perform secure message communications between DIN-PACS nodes in the VRE network. The Meta-Manager has a fail-safe architecture that allows the master Meta-Manager function to float to regional Meta-Manager sites in case of server failure. A prototype of the CORBA-based Meta-Manager is being developed by the University of Arizona's Computer Engineering Research Laboratory using the unified modeling language (UML) as a design tool. The prototype will implement the main functions described in the Meta-Manager design specification. The results of this project are expected to reengineer the process of radiology in the military and have extensions to commercial radiology environments.

Design and implementation of a telemedicine system using Bluetooth protocol and GSM/GPRS network, for real time remote patient monitoring.

PubMed

Jasemian, Yousef; Nielsen, Lars Arendt

2005-01-01

This paper introduces the design and implementation of a generic wireless and Real-time Multi-purpose Health Care Telemedicine system applying Bluetooth protocol, Global System for Mobile Communications (GSM) and General Packet Radio Service (GPRS). The paper explores the factors that should be considered when evaluating different technologies for application in telemedicine system. The design and implementation of an embedded wireless communication platform utilising Bluetooth protocol is described, and the implementation problems and limitations are investigated. The system is tested and its telecommunication general aspects are verified. The results showed that the system has (97.9 +/- 1.3)% Up-time, 2.5 x 10(-5) Bit Error Rate, 1% Dropped Call Rate, 97.4% Call Success Rate, 5 second transmission delay in average, (3.42 +/- 0.11) kbps throughput, and the system may have application in electrocardiography.

Optical fiber cable and wiring techniques for fiber to the home (FTTH)

NASA Astrophysics Data System (ADS)

Takai, Hirofumi; Yamauchi, Osamu

2009-08-01

NTT group's new medium-term management strategy calls for 20 million optical subscribers by 2010, and NTT Laboratories is pushing forward to meet this goal. Before that date, an efficient optical access network must be constructed, and afterwards, when the era of mass optical communications finally arrives, the facilities and equipment supporting the network will have to be effectively operated and maintained. At NTT Access Network Service Systems Laboratories, we are developing various technologies to correspond to the massive deployment of optical broadband services. We are also developing various new technologies for efficiently operating optical access network systems that will continue to expand in the future, and to supply our customers with good services. This paper provides an overview of the new optical access network system technologies that are being developed at NTT Access Network Service Systems Laboratories to address these issues.

Study on the effect of sink moving trajectory on wireless sensor networks

NASA Astrophysics Data System (ADS)

Zhong, Peijun; Ruan, Feng

2018-03-01

Wireless sensor networks are developing very fast in recent years, due to their wide potential applications. However there exists the so-called hot spot problem, namely the nodes close to static sink node tend to die earlier than other nodes since they have heavier burden to forward. The introduction of mobile sink node can effectively alleviate this problem since sink node can move along certain trajectories, causing hot spot nodes more evenly distributed. In this paper, we make extensive experimental simulations for circular sensor network, with one mobile sink moving along different radius circumference. The whole network is divided into several clusters and there is one cluster head (CH) inside each cluster. The ordinary sensors communicate with CH and CHs construct a chain until the sink node. Simulation results show that the best network performance appears when sink moves along 0.25 R in terms of network lifetime.

Inferring Social Status and Rich Club Effects in Enterprise Communication Networks

PubMed Central

Dong, Yuxiao; Tang, Jie; Chawla, Nitesh V.; Lou, Tiancheng; Yang, Yang; Wang, Bai

2015-01-01

Social status, defined as the relative rank or position that an individual holds in a social hierarchy, is known to be among the most important motivating forces in social behaviors. In this paper, we consider the notion of status from the perspective of a position or title held by a person in an enterprise. We study the intersection of social status and social networks in an enterprise. We study whether enterprise communication logs can help reveal how social interactions and individual status manifest themselves in social networks. To that end, we use two enterprise datasets with three communication channels — voice call, short message, and email — to demonstrate the social-behavioral differences among individuals with different status. We have several interesting findings and based on these findings we also develop a model to predict social status. On the individual level, high-status individuals are more likely to be spanned as structural holes by linking to people in parts of the enterprise networks that are otherwise not well connected to one another. On the community level, the principle of homophily, social balance and clique theory generally indicate a “rich club” maintained by high-status individuals, in the sense that this community is much more connected, balanced and dense. Our model can predict social status of individuals with 93% accuracy. PMID:25822343

Structure and function of complex brain networks

PubMed Central

Sporns, Olaf

2013-01-01

An increasing number of theoretical and empirical studies approach the function of the human brain from a network perspective. The analysis of brain networks is made feasible by the development of new imaging acquisition methods as well as new tools from graph theory and dynamical systems. This review surveys some of these methodological advances and summarizes recent findings on the architecture of structural and functional brain networks. Studies of the structural connectome reveal several modules or network communities that are interlinked by hub regions mediating communication processes between modules. Recent network analyses have shown that network hubs form a densely linked collective called a “rich club,” centrally positioned for attracting and dispersing signal traffic. In parallel, recordings of resting and task-evoked neural activity have revealed distinct resting-state networks that contribute to functions in distinct cognitive domains. Network methods are increasingly applied in a clinical context, and their promise for elucidating neural substrates of brain and mental disorders is discussed. PMID:24174898

Optimization of Applications with Non-blocking Neighborhood Collectives via Multisends on the Blue Gene/P Supercomputer.

PubMed

Kumar, Sameer; Heidelberger, Philip; Chen, Dong; Hines, Michael

2010-04-19

We explore the multisend interface as a data mover interface to optimize applications with neighborhood collective communication operations. One of the limitations of the current MPI 2.1 standard is that the vector collective calls require counts and displacements (zero and nonzero bytes) to be specified for all the processors in the communicator. Further, all the collective calls in MPI 2.1 are blocking and do not permit overlap of communication with computation. We present the record replay persistent optimization to the multisend interface that minimizes the processor overhead of initiating the collective. We present four different case studies with the multisend API on Blue Gene/P (i) 3D-FFT, (ii) 4D nearest neighbor exchange as used in Quantum Chromodynamics, (iii) NAMD and (iv) neural network simulator NEURON. Performance results show 1.9× speedup with 32(3) 3D-FFTs, 1.9× speedup for 4D nearest neighbor exchange with the 2(4) problem, 1.6× speedup in NAMD and almost 3× speedup in NEURON with 256K cells and 1k connections/cell.

Puerto Rico Seismic Network Operations During and After the Hurricane Maria: Response, Continuity of Operations, and Experiences

NASA Astrophysics Data System (ADS)

Vanacore, E. A.; Baez-Sanchez, G.; Huerfano, V.; Lopez, A. M.; Lugo, J.

2017-12-01

The Puerto Rico Seismic Network (PRSN) is an integral part of earthquake and tsunami monitoring in Puerto Rico and the Virgin Islands. The PRSN conducts scientific research as part of the University of Puerto Rico Mayaguez, conducts the earthquake monitoring for the region, runs extensive earthquake and tsunami education and outreach programs, and acts as a Tsunami Warning Focal Point Alternate for Puerto Rico. During and in the immediate aftermath of Hurricane Maria, the PRSN duties and responsibilities evolved from a seismic network to a major information and communications center for the western side of Puerto Rico. Hurricane Maria effectively destroyed most communications on island, critically between the eastern side of the island where Puerto Rico's Emergency Management's (PREMA) main office and the National Weather Service (NWS) is based and the western side of the island. Additionally, many local emergency management agencies on the western side of the island lost a satellite based emergency management information system called EMWIN which provides critical tsunami and weather information. PRSN's EMWIN system remained functional and consequently via this system and radio communications PRSN became the only information source for NWS warnings and bulletins, tsunami alerts, and earthquake information for western Puerto Rico. Additionally, given the functional radio and geographic location of the PRSN, the network became a critical communications relay for local emergency management. Here we will present the PRSN response in relation to Hurricane Maria including the activation of the PRSN devolution plan, adoption of duties, experiences and lessons learned for continuity of operations and adoption of responsibilities during future catastrophic events.

A Case for Open Network Health Systems: Systems as Networks in Public Mental Health

PubMed Central

Rhodes, Michael Grant; de Vries, Marten W.

2017-01-01

Increases in incidents involving so-called confused persons have brought attention to the potential costs of recent changes to public mental health (PMH) services in the Netherlands. Decentralized under the (Community) Participation Act (2014), local governments must find resources to compensate for reduced central funding to such services or "innovate." But innovation, even when pressure for change is intense, is difficult. This perspective paper describes experience during and after an investigation into a particularly violent incident and murder. The aim was to provide recommendations to improve the functioning of local PMH services. The investigation concluded that no specific failure by an individual professional or service provider facility led to the murder. Instead, also as a result of the Participation Act that severed communication lines between individuals and organizations, information sharing failures were likely to have reduced system level capacity to identify risks. The methods and analytical frameworks employed to reach this conclusion, also lead to discussion as to the plausibility of an unconventional solution. If improving communication is the primary problem, non-hierarchical information, and organizational networks arise as possible and innovative system solutions. The proposal for debate is that traditional "health system" definitions, literature and narratives, and operating assumptions in public (mental) health are ‘locked in’ constraining technical and organization innovations. If we view a "health system" as an adaptive system of economic and social "networks," it becomes clear that the current orthodox solution, the so-called integrated health system, typically results in a "centralized hierarchical" or "tree" network. An overlooked alternative that breaks out of the established policy narratives is the view of a ‘health systems’ as a non-hierarchical organizational structure or ‘Open Network.’ In turn, this opens new technological and organizational possibilities in seeking policy solutions, and suggests an alternative governance model of huge potential value in public health both locally and globally. PMID:28812792

Distributed clone detection in static wireless sensor networks: random walk with network division.

PubMed

Khan, Wazir Zada; Aalsalem, Mohammed Y; Saad, N M

2015-01-01

Wireless Sensor Networks (WSNs) are vulnerable to clone attacks or node replication attacks as they are deployed in hostile and unattended environments where they are deprived of physical protection, lacking physical tamper-resistance of sensor nodes. As a result, an adversary can easily capture and compromise sensor nodes and after replicating them, he inserts arbitrary number of clones/replicas into the network. If these clones are not efficiently detected, an adversary can be further capable to mount a wide variety of internal attacks which can emasculate the various protocols and sensor applications. Several solutions have been proposed in the literature to address the crucial problem of clone detection, which are not satisfactory as they suffer from some serious drawbacks. In this paper we propose a novel distributed solution called Random Walk with Network Division (RWND) for the detection of node replication attack in static WSNs which is based on claimer-reporter-witness framework and combines a simple random walk with network division. RWND detects clone(s) by following a claimer-reporter-witness framework and a random walk is employed within each area for the selection of witness nodes. Splitting the network into levels and areas makes clone detection more efficient and the high security of witness nodes is ensured with moderate communication and memory overheads. Our simulation results show that RWND outperforms the existing witness node based strategies with moderate communication and memory overheads.

The middleware architecture supports heterogeneous network systems for module-based personal robot system

NASA Astrophysics Data System (ADS)

Choo, Seongho; Li, Vitaly; Choi, Dong Hee; Jung, Gi Deck; Park, Hong Seong; Ryuh, Youngsun

2005-12-01

On developing the personal robot system presently, the internal architecture is every module those occupy separated functions are connected through heterogeneous network system. This module-based architecture supports specialization and division of labor at not only designing but also implementation, as an effect of this architecture, it can reduce developing times and costs for modules. Furthermore, because every module is connected among other modules through network systems, we can get easy integrations and synergy effect to apply advanced mutual functions by co-working some modules. In this architecture, one of the most important technologies is the network middleware that takes charge communications among each modules connected through heterogeneous networks systems. The network middleware acts as the human nerve system inside of personal robot system; it relays, transmits, and translates information appropriately between modules that are similar to human organizations. The network middleware supports various hardware platform, heterogeneous network systems (Ethernet, Wireless LAN, USB, IEEE 1394, CAN, CDMA-SMS, RS-232C). This paper discussed some mechanisms about our network middleware to intercommunication and routing among modules, methods for real-time data communication and fault-tolerant network service. There have designed and implemented a layered network middleware scheme, distributed routing management, network monitoring/notification technology on heterogeneous networks for these goals. The main theme is how to make routing information in our network middleware. Additionally, with this routing information table, we appended some features. Now we are designing, making a new version network middleware (we call 'OO M/W') that can support object-oriented operation, also are updating program sources itself for object-oriented architecture. It is lighter, faster, and can support more operation systems and heterogeneous network systems, but other general purposed middlewares like CORBA, UPnP, etc. can support only one network protocol or operating system.

Communication Optimizations for a Wireless Distributed Prognostic Framework

NASA Technical Reports Server (NTRS)

Saha, Sankalita; Saha, Bhaskar; Goebel, Kai

2009-01-01

Distributed architecture for prognostics is an essential step in prognostic research in order to enable feasible real-time system health management. Communication overhead is an important design problem for such systems. In this paper we focus on communication issues faced in the distributed implementation of an important class of algorithms for prognostics - particle filters. In spite of being computation and memory intensive, particle filters lend well to distributed implementation except for one significant step - resampling. We propose new resampling scheme called parameterized resampling that attempts to reduce communication between collaborating nodes in a distributed wireless sensor network. Analysis and comparison with relevant resampling schemes is also presented. A battery health management system is used as a target application. A new resampling scheme for distributed implementation of particle filters has been discussed in this paper. Analysis and comparison of this new scheme with existing resampling schemes in the context for minimizing communication overhead have also been discussed. Our proposed new resampling scheme performs significantly better compared to other schemes by attempting to reduce both the communication message length as well as number total communication messages exchanged while not compromising prediction accuracy and precision. Future work will explore the effects of the new resampling scheme in the overall computational performance of the whole system as well as full implementation of the new schemes on the Sun SPOT devices. Exploring different network architectures for efficient communication is an importance future research direction as well.

Space Communications and Navigation (SCaN) Network Simulation Tool Development and Its Use Cases

NASA Technical Reports Server (NTRS)

Jennings, Esther; Borgen, Richard; Nguyen, Sam; Segui, John; Stoenescu, Tudor; Wang, Shin-Ywan; Woo, Simon; Barritt, Brian; Chevalier, Christine; Eddy, Wesley

2009-01-01

In this work, we focus on the development of a simulation tool to assist in analysis of current and future (proposed) network architectures for NASA. Specifically, the Space Communications and Navigation (SCaN) Network is being architected as an integrated set of new assets and a federation of upgraded legacy systems. The SCaN architecture for the initial missions for returning humans to the moon and beyond will include the Space Network (SN) and the Near-Earth Network (NEN). In addition to SCaN, the initial mission scenario involves a Crew Exploration Vehicle (CEV), the International Space Station (ISS) and NASA Integrated Services Network (NISN). We call the tool being developed the SCaN Network Integration and Engineering (SCaN NI&E) Simulator. The intended uses of such a simulator are: (1) to characterize performance of particular protocols and configurations in mission planning phases; (2) to optimize system configurations by testing a larger parameter space than may be feasible in either production networks or an emulated environment; (3) to test solutions in order to find issues/risks before committing more significant resources needed to produce real hardware or flight software systems. We describe two use cases of the tool: (1) standalone simulation of CEV to ISS baseline scenario to determine network performance, (2) participation in Distributed Simulation Integration Laboratory (DSIL) tests to perform function testing and verify interface and interoperability of geographically dispersed simulations/emulations.

WEB Services Networks and Technological Hybrids — The Integration Challenges of WAN Distributed Computing for ASP Providers

NASA Astrophysics Data System (ADS)

Mroczkiewicz, Pawel

A necessity of integration of both information systems and office software existing in organizations has had a long history. The beginning of this kind of solutions reaches back to the old generation of network protocols called EDI (Electronic Data Interchange) and EDIFACT standard, which was initiated in 1988 and has dynamically evolved ever since (S. Michalski, M. Suskiewicz, 1995). The mentioned protocol was usually used for converting documents into natural formats processed by applications. It caused problems with binary files and, furthermore, the communication mechanisms had to be modified each time new documents or applications were added. When we compare EDI with the previously used communication mechanisms, EDI was a great step forward as it was the first, big scale attempt to define standards of data interchange between the applications in business transactions (V. Leyland, 1995, p. 47).

Emotion-Bracelet: A Web Service for Expressing Emotions through an Electronic Interface.

PubMed

Martinez, Alicia; Estrada, Hugo; Molina, Alejandra; Mejia, Manuel; Perez, Joaquin

2016-11-24

The mechanisms to communicate emotions have dramatically changed in the last 10 years with social networks, where users massively communicate their emotional states by using the Internet. However, people with socialization problems have difficulty expressing their emotions verbally or interpreting the environment and providing an appropriate emotional response. In this paper, a novel solution called the Emotion-Bracelet is presented that combines a hardware device and a software system. The proposed approach identifies the polarity and emotional intensity of texts published on a social network site by performing real-time processing using a web service. It also shows emotions with a LED matrix using five emoticons that represent positive, very positive, negative, very negative, and neutral states. The Emotion-Bracelet is designed to help people express their emotions in a non-intrusive way, thereby expanding the social aspect of human emotions.

Emotion-Bracelet: A Web Service for Expressing Emotions through an Electronic Interface

PubMed Central

Martinez, Alicia; Estrada, Hugo; Molina, Alejandra; Mejia, Manuel; Perez, Joaquin

2016-01-01

The mechanisms to communicate emotions have dramatically changed in the last 10 years with social networks, where users massively communicate their emotional states by using the Internet. However, people with socialization problems have difficulty expressing their emotions verbally or interpreting the environment and providing an appropriate emotional response. In this paper, a novel solution called the Emotion-Bracelet is presented that combines a hardware device and a software system. The proposed approach identifies the polarity and emotional intensity of texts published on a social network site by performing real-time processing using a web service. It also shows emotions with a LED matrix using five emoticons that represent positive, very positive, negative, very negative, and neutral states. The Emotion-Bracelet is designed to help people express their emotions in a non-intrusive way, thereby expanding the social aspect of human emotions. PMID:27886130

Recovery plan for laurel wilt on redbay and other forest species caused by Raffaelea lauricola and disseminated by Xyleborus glabratus

Treesearch

M. A. Hughes; J.A. Smith; R. C. Ploetz; P. E. Kendra; Albert (Bud) Mayfield; James Hanula; J. Hulcr; L.L. Stelinski; S. Cameron;  J. J. Riggins; D. Carrillo; R. Rabaglia; J. Eickwort

2015-01-01

This recovery plan is one of several disease-specific documents produced as part of the National Plant Disease Recovery System (NPDRS) called for in Homeland Security Presidential Directive Number 9 (HSPD-9). The purpose of the NPDRS is to insure that the tools, infrastructure, communication networks, and capacity required to mitigate the impact of high-consequence...

Joint Experiment on Scalable Parallel Processors (JESPP) Parallel Data Management

DTIC Science & Technology

2006-05-01

management and analysis tool, called Simulation Data Grid ( SDG ). The design principles driving the design of SDG are: 1) minimize network communication...or SDG . In this report, an initial prototype implementation of this system is described. This project follows on earlier research, primarily...distributed logging system had some 2 limitations. These limitations will be described in this report, and how the SDG addresses these limitations. 3.0

Feasibility of Using Interstate Highway Right-of-Way to Obtain a More Survivable Fiber-Optics Network

DTIC Science & Technology

1988-01-01

to rees- tablish connectivity for governmental users on a damaged net- work in...telephone call originates as an electrical current at a user’s home or business and travels to a telephone switching office over a local loop of copper...infrastructure. HISTORICAL PERSPECTIVE A timeline of key events with respect to the two key study components-fiber-optics communications

Process Synchronization and Data Communication between Processes in Real Time Local Area Networks.

DTIC Science & Technology

1985-12-01

52 APPENDIX A: PROCEDURE MAKETABLE .............. 54 APPENDIX B: PROCEDURE MAKEMESSAGE ............. 56 APPENDIX C: PROCEDURE...item. The relation table is built by the driver during system initialization by the procedure maketable , see Appendix A. This procedure reads the file... MAKETABLE Procedure maketable is the first procedure called by the driver. It sets up the relation table in local RAM of SBC 1 by reading the information

CTC Sentinel. Volume 2, Issue 4, April 2009. Defining the Punjabi Taliban Network

DTIC Science & Technology

2009-04-01

Province (which has better educational facilities) and urban linkages where internet access and communications equipment are more readily available...calls by using Voice over Internet Protocol (VoIP) technology. sending an e-mail from Afghanistan explaining why he was fighting jihad.49 One of...ascendancy to power and collaborative approach represents to al-Qa`ida’s legitimacy. President Bush’s controversial policies and public persona

A New Remote Communications Link to Reduce Residential PV Solar Costs

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

King, Randy; Sugiyama, Rod

Monitoring of PV/DER site production is expensive to install and unreliable. Among third party systems providers, lost communications links are a growing concern. Nearly 20% of links are failing, provisioning is complex, recovery is expensive, production data is lost, and access is fragmented. FleetLink is a new concept in DER system communications, purpose built for lowering the cost of maintaining active contact with residential end user sites and ensuring that production data is reliably available to third party systems providers. Systems providers require accurate, secure system monitoring and reporting of production data and system faults while driving down overall costsmore » to compete effectively. This plug and play, independently operating communications solution lowers the cost of fleet contact from typically .08 dollars-$.12/W down to .02 dollars -.03/W including installation and maintenance expenses. FleetLink establishes a breakthrough in simplicity that facilitates rapid expansion of residential solar by reducing initial capital outlay and lowering installation labor time and skill levels. The solution also facilitates higher DER installation growth rates by driving down maintenance costs and eliminating communications trouble calls. This is accomplished by the FleetLink’s unique network technology that enables dynamic network configuration for fast changes, and active, self-healing DER site contact for uptime assurance. Using an open source network framework with proprietary, application specific enhancements, FleetLink independently manages connectivity, security, recovery, grid control communications, and fleet expansion while presenting a compliant SunSpec interface to the third party operations centers. The net system cost savings of at least .05 dollars/W supports the SunShot cost goals and the flexibility and scalability of the solution accelerates the velocity and ubiquitous adoption of solar.« less

Evaluation of the impact of furniture on communications performance for ubiquitous deployment of Wireless Sensor Networks in smart homes.

PubMed

Bleda, Andrés L; Jara, Antonio J; Maestre, Rafael; Santa, Guadalupe; Gómez Skarmeta, Antonio F

2012-01-01

The extensions of the environment with the integration of sensing systems in any space, in conjunction with ubiquitous computing are enabling the so-called Smart Space Sensor Networks. This new generation of networks are offering full connectivity with any object, through the Internet of Things (IoT) and/or the Web, i.e., the Web of Things. These connectivity capabilities are making it feasible to sense the behaviours of people at home and act accordingly. These sensing systems must be integrated within typical elements found at home such as furniture. For that reason, this work considers furniture as an interesting element for the transparent location of sensors. Furniture is a ubiquitous object, i.e., it can be found everywhere at home or the office, and it can integrate and hide the sensors of a network. This work addresses the lack of an exhaustive study of the effect of furniture on signal losses. In addition an easy-to-use tool for estimating the robustness of the communication channel among the sensor nodes and gateways is proposed. Specifically, the losses in a sensor network signal due to the materials found within the communication link are evaluated. Then, this work proposes a software tool that gathers the obtained results and is capable of evaluating the impact of a given set of materials on the communications. This tool also provides a mechanism to optimize the sensor network deployments during the definition of smart spaces. Specifically, it provides information such as: maximum distances between sensor nodes, most suitable type of furniture to integrate sensors, or battery life of sensor nodes. This tool has been validated empirically in the lab, and it is currently being used by several enterprise partners of the Technological Centre of Furniture and Wood in the southeast of Spain.

Evaluation of the Impact of Furniture on Communications Performance for Ubiquitous Deployment of Wireless Sensor Networks in Smart Homes

PubMed Central

Bleda, Andrés L.; Jara, Antonio J.; Maestre, Rafael; Santa, Guadalupe; Gómez Skarmeta, Antonio F.

2012-01-01

The extensions of the environment with the integration of sensing systems in any space, in conjunction with ubiquitous computing are enabling the so-called Smart Space Sensor Networks. This new generation of networks are offering full connectivity with any object, through the Internet of Things (IoT) and/or the Web, i.e., the Web of Things. These connectivity capabilities are making it feasible to sense the behaviours of people at home and act accordingly. These sensing systems must be integrated within typical elements found at home such as furniture. For that reason, this work considers furniture as an interesting element for the transparent location of sensors. Furniture is a ubiquitous object, i.e., it can be found everywhere at home or the office, and it can integrate and hide the sensors of a network. This work addresses the lack of an exhaustive study of the effect of furniture on signal losses. In addition an easy-to-use tool for estimating the robustness of the communication channel among the sensor nodes and gateways is proposed. Specifically, the losses in a sensor network signal due to the materials found within the communication link are evaluated. Then, this work proposes a software tool that gathers the obtained results and is capable of evaluating the impact of a given set of materials on the communications. This tool also provides a mechanism to optimize the sensor network deployments during the definition of smart spaces. Specifically, it provides information such as: maximum distances between sensor nodes, most suitable type of furniture to integrate sensors, or battery life of sensor nodes. This tool has been validated empirically in the lab, and it is currently being used by several enterprise partners of the Technological Centre of Furniture and Wood in the southeast of Spain. PMID:22778653

A Novel Distributed Privacy Paradigm for Visual Sensor Networks Based on Sharing Dynamical Systems

NASA Astrophysics Data System (ADS)

Luh, William; Kundur, Deepa; Zourntos, Takis

2006-12-01

Visual sensor networks (VSNs) provide surveillance images/video which must be protected from eavesdropping and tampering en route to the base station. In the spirit of sensor networks, we propose a novel paradigm for securing privacy and confidentiality in a distributed manner. Our paradigm is based on the control of dynamical systems, which we show is well suited for VSNs due to its low complexity in terms of processing and communication, while achieving robustness to both unintentional noise and intentional attacks as long as a small subset of nodes are affected. We also present a low complexity algorithm called TANGRAM to demonstrate the feasibility of applying our novel paradigm to VSNs. We present and discuss simulation results of TANGRAM.

Data reliability in complex directed networks

NASA Astrophysics Data System (ADS)

Sanz, Joaquín; Cozzo, Emanuele; Moreno, Yamir

2013-12-01

The availability of data from many different sources and fields of science has made it possible to map out an increasing number of networks of contacts and interactions. However, quantifying how reliable these data are remains an open problem. From Biology to Sociology and Economics, the identification of false and missing positives has become a problem that calls for a solution. In this work we extend one of the newest, best performing models—due to Guimerá and Sales-Pardo in 2009—to directed networks. The new methodology is able to identify missing and spurious directed interactions with more precision than previous approaches, which renders it particularly useful for analyzing data reliability in systems like trophic webs, gene regulatory networks, communication patterns and several social systems. We also show, using real-world networks, how the method can be employed to help search for new interactions in an efficient way.

VLSI Implementation of a 2.8 Gevent/s Packet-Based AER Interface with Routing and Event Sorting Functionality

PubMed Central

Scholze, Stefan; Schiefer, Stefan; Partzsch, Johannes; Hartmann, Stephan; Mayr, Christian Georg; Höppner, Sebastian; Eisenreich, Holger; Henker, Stephan; Vogginger, Bernhard; Schüffny, Rene

2011-01-01

State-of-the-art large-scale neuromorphic systems require sophisticated spike event communication between units of the neural network. We present a high-speed communication infrastructure for a waferscale neuromorphic system, based on application-specific neuromorphic communication ICs in an field programmable gate arrays (FPGA)-maintained environment. The ICs implement configurable axonal delays, as required for certain types of dynamic processing or for emulating spike-based learning among distant cortical areas. Measurements are presented which show the efficacy of these delays in influencing behavior of neuromorphic benchmarks. The specialized, dedicated address-event-representation communication in most current systems requires separate, low-bandwidth configuration channels. In contrast, the configuration of the waferscale neuromorphic system is also handled by the digital packet-based pulse channel, which transmits configuration data at the full bandwidth otherwise used for pulse transmission. The overall so-called pulse communication subgroup (ICs and FPGA) delivers a factor 25–50 more event transmission rate than other current neuromorphic communication infrastructures. PMID:22016720

The Advanced Communication Technology Satellite and ISDN

NASA Technical Reports Server (NTRS)

Lowry, Peter A.

1996-01-01

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

Interconnecting heterogeneous database management systems

NASA Technical Reports Server (NTRS)

Gligor, V. D.; Luckenbaugh, G. L.

1984-01-01

It is pointed out that there is still a great need for the development of improved communication between remote, heterogeneous database management systems (DBMS). Problems regarding the effective communication between distributed DBMSs are primarily related to significant differences between local data managers, local data models and representations, and local transaction managers. A system of interconnected DBMSs which exhibit such differences is called a network of distributed, heterogeneous DBMSs. In order to achieve effective interconnection of remote, heterogeneous DBMSs, the users must have uniform, integrated access to the different DBMs. The present investigation is mainly concerned with an analysis of the existing approaches to interconnecting heterogeneous DBMSs, taking into account four experimental DBMS projects.

One-Time URL: A Proximity Security Mechanism between Internet of Things and Mobile Devices.

PubMed

Solano, Antonio; Dormido, Raquel; Duro, Natividad; González, Víctor

2016-10-13

The aim of this paper is to determine the physical proximity of connected things when they are accessed from a smartphone. Links between connected things and mobile communication devices are temporarily created by means of dynamic URLs (uniform resource locators) which may be easily discovered with pervasive short-range radio frequency technologies available on smartphones. In addition, a multi cross domain silent logging mechanism to allow people to interact with their surrounding connected things from their mobile communication devices is presented. The proposed mechanisms are based in web standards technologies, evolving our social network of Internet of Things towards the so-called Web of Things.

From calls to communities: a model for time-varying social networks

NASA Astrophysics Data System (ADS)

Laurent, Guillaume; Saramäki, Jari; Karsai, Márton

2015-11-01

Social interactions vary in time and appear to be driven by intrinsic mechanisms that shape the emergent structure of social networks. Large-scale empirical observations of social interaction structure have become possible only recently, and modelling their dynamics is an actual challenge. Here we propose a temporal network model which builds on the framework of activity-driven time-varying networks with memory. The model integrates key mechanisms that drive the formation of social ties - social reinforcement, focal closure and cyclic closure, which have been shown to give rise to community structure and small-world connectedness in social networks. We compare the proposed model with a real-world time-varying network of mobile phone communication, and show that they share several characteristics from heterogeneous degrees and weights to rich community structure. Further, the strong and weak ties that emerge from the model follow similar weight-topology correlations as real-world social networks, including the role of weak ties.

Adapting Behavioral Interventions for Social Media Delivery

PubMed Central

Waring, Molly E; May, Christine N; Ding, Eric Y; Kunz, Werner H; Hayes, Rashelle; Oleski, Jessica L

2016-01-01

Patients are increasingly using online social networks (ie, social media) to connect with other patients and health care professionals—a trend called peer-to-peer health care. Because online social networks provide a means for health care professionals to communicate with patients, and for patients to communicate with each other, an opportunity exists to use social media as a modality to deliver behavioral interventions. Social media-delivered behavioral interventions have the potential to reduce the expense of behavioral interventions by eliminating visits, as well as increase our access to patients by becoming embedded in their social media feeds. Trials of online social network-delivered behavioral interventions have shown promise, but much is unknown about intervention development and methodology. In this paper, we discuss the process by which investigators can translate behavioral interventions for social media delivery. We present a model that describes the steps and decision points in this process, including the necessary training and reporting requirements. We also discuss issues pertinent to social media-delivered interventions, including cost, scalability, and privacy. Finally, we identify areas of research that are needed to optimize this emerging behavioral intervention modality. PMID:26825969

Adapting Behavioral Interventions for Social Media Delivery.

PubMed

Pagoto, Sherry; Waring, Molly E; May, Christine N; Ding, Eric Y; Kunz, Werner H; Hayes, Rashelle; Oleski, Jessica L

2016-01-29

Patients are increasingly using online social networks (ie, social media) to connect with other patients and health care professionals--a trend called peer-to-peer health care. Because online social networks provide a means for health care professionals to communicate with patients, and for patients to communicate with each other, an opportunity exists to use social media as a modality to deliver behavioral interventions. Social media-delivered behavioral interventions have the potential to reduce the expense of behavioral interventions by eliminating visits, as well as increase our access to patients by becoming embedded in their social media feeds. Trials of online social network-delivered behavioral interventions have shown promise, but much is unknown about intervention development and methodology. In this paper, we discuss the process by which investigators can translate behavioral interventions for social media delivery. We present a model that describes the steps and decision points in this process, including the necessary training and reporting requirements. We also discuss issues pertinent to social media-delivered interventions, including cost, scalability, and privacy. Finally, we identify areas of research that are needed to optimize this emerging behavioral intervention modality.

Macromolecular networks and intelligence in microorganisms

PubMed Central

Westerhoff, Hans V.; Brooks, Aaron N.; Simeonidis, Evangelos; García-Contreras, Rodolfo; He, Fei; Boogerd, Fred C.; Jackson, Victoria J.; Goncharuk, Valeri; Kolodkin, Alexey

2014-01-01

Living organisms persist by virtue of complex interactions among many components organized into dynamic, environment-responsive networks that span multiple scales and dimensions. Biological networks constitute a type of information and communication technology (ICT): they receive information from the outside and inside of cells, integrate and interpret this information, and then activate a response. Biological networks enable molecules within cells, and even cells themselves, to communicate with each other and their environment. We have become accustomed to associating brain activity – particularly activity of the human brain – with a phenomenon we call “intelligence.” Yet, four billion years of evolution could have selected networks with topologies and dynamics that confer traits analogous to this intelligence, even though they were outside the intercellular networks of the brain. Here, we explore how macromolecular networks in microbes confer intelligent characteristics, such as memory, anticipation, adaptation and reflection and we review current understanding of how network organization reflects the type of intelligence required for the environments in which they were selected. We propose that, if we were to leave terms such as “human” and “brain” out of the defining features of “intelligence,” all forms of life – from microbes to humans – exhibit some or all characteristics consistent with “intelligence.” We then review advances in genome-wide data production and analysis, especially in microbes, that provide a lens into microbial intelligence and propose how the insights derived from quantitatively characterizing biomolecular networks may enable synthetic biologists to create intelligent molecular networks for biotechnology, possibly generating new forms of intelligence, first in silico and then in vivo. PMID:25101076

Twitter web-service for soft agent reporting in persistent surveillance systems

NASA Astrophysics Data System (ADS)

Rababaah, Haroun; Shirkhodaie, Amir

2010-04-01

Persistent surveillance is an intricate process requiring monitoring, gathering, processing, tracking, and characterization of many spatiotemporal events occurring concurrently. Data associated with events can be readily attained by networking of hard (physical) sensors. Sensors may have homogeneous or heterogeneous (hybrid) sensing modalities with different communication bandwidth requirements. Complimentary to hard sensors are human observers or "soft sensors" that can report occurrences of evolving events via different communication devices (e.g., texting, cell phones, emails, instant messaging, etc.) to the command control center. However, networking of human observers in ad-hoc way is rather a difficult task. In this paper, we present a Twitter web-service for soft agent reporting in persistent surveillance systems (called Web-STARS). The objective of this web-service is to aggregate multi-source human observations in hybrid sensor networks rapidly. With availability of Twitter social network, such a human networking concept can not only be realized for large scale persistent surveillance systems (PSS), but also, it can be employed with proper interfaces to expedite rapid events reporting by human observers. The proposed technique is particularly suitable for large-scale persistent surveillance systems with distributed soft and hard sensor networks. The efficiency and effectiveness of the proposed technique is measured experimentally by conducting several simulated persistent surveillance scenarios. It is demonstrated that by fusion of information from hard and soft agents improves understanding of common operating picture and enhances situational awareness.

Design and implementation of an Internet based effective controlling and monitoring system with wireless fieldbus communications technologies for process automation--an experimental study.

PubMed

Cetinceviz, Yucel; Bayindir, Ramazan

2012-05-01

The network requirements of control systems in industrial applications increase day by day. The Internet based control system and various fieldbus systems have been designed in order to meet these requirements. This paper describes an Internet based control system with wireless fieldbus communication designed for distributed processes. The system was implemented as an experimental setup in a laboratory. In industrial facilities, the process control layer and the distance connection of the distributed control devices in the lowest levels of the industrial production environment are provided with fieldbus networks. In this paper, the Internet based control system that will be able to meet the system requirements with a new-generation communication structure, which is called wired/wireless hybrid system, has been designed on field level and carried out to cover all sectors of distributed automation, from process control, to distributed input/output (I/O). The system has been accomplished by hardware structure with a programmable logic controller (PLC), a communication processor (CP) module, two industrial wireless modules and a distributed I/O module, Motor Protection Package (MPP) and software structure with WinCC flexible program used for the screen of Scada (Supervisory Control And Data Acquisition), SIMATIC MANAGER package program ("STEP7") used for the hardware and network configuration and also for downloading control program to PLC. Copyright © 2012 ISA. Published by Elsevier Ltd. All rights reserved.

Determinants of mobile phone output power in a multinational study: implications for exposure assessment.

PubMed

Vrijheid, M; Mann, S; Vecchia, P; Wiart, J; Taki, M; Ardoino, L; Armstrong, B K; Auvinen, A; Bédard, D; Berg-Beckhoff, G; Brown, J; Chetrit, A; Collatz-Christensen, H; Combalot, E; Cook, A; Deltour, I; Feychting, M; Giles, G G; Hepworth, S J; Hours, M; Iavarone, I; Johansen, C; Krewski, D; Kurttio, P; Lagorio, S; Lönn, S; McBride, M; Montestrucq, L; Parslow, R C; Sadetzki, S; Schüz, J; Tynes, T; Woodward, A; Cardis, E

2009-10-01

The output power of a mobile phone is directly related to its radiofrequency (RF) electromagnetic field strength, and may theoretically vary substantially in different networks and phone use circumstances due to power control technologies. To improve indices of RF exposure for epidemiological studies, we assessed determinants of mobile phone output power in a multinational study. More than 500 volunteers in 12 countries used Global System for Mobile communications software-modified phones (GSM SMPs) for approximately 1 month each. The SMPs recorded date, time, and duration of each call, and the frequency band and output power at fixed sampling intervals throughout each call. Questionnaires provided information on the typical circumstances of an individual's phone use. Linear regression models were used to analyse the influence of possible explanatory variables on the average output power and the percentage call time at maximum power for each call. Measurements of over 60,000 phone calls showed that the average output power was approximately 50% of the maximum, and that output power varied by a factor of up to 2 to 3 between study centres and network operators. Maximum power was used during a considerable proportion of call time (39% on average). Output power decreased with increasing call duration, but showed little variation in relation to reported frequency of use while in a moving vehicle or inside buildings. Higher output powers for rural compared with urban use of the SMP were observed principally in Sweden where the study covered very sparsely populated areas. Average power levels are substantially higher than the minimum levels theoretically achievable in GSM networks. Exposure indices could be improved by accounting for average power levels of different telecommunications systems. There appears to be little value in gathering information on circumstances of phone use other than use in very sparsely populated regions.

Enabling MEMS technologies for communications systems

NASA Astrophysics Data System (ADS)

Lubecke, Victor M.; Barber, Bradley P.; Arney, Susanne

2001-11-01

Modern communications demands have been steadily growing not only in size, but sophistication. Phone calls over copper wires have evolved into high definition video conferencing over optical fibers, and wireless internet browsing. The technology used to meet these demands is under constant pressure to provide increased capacity, speed, and efficiency, all with reduced size and cost. Various MEMS technologies have shown great promise for meeting these challenges by extending the performance of conventional circuitry and introducing radical new systems approaches. A variety of strategic MEMS structures including various cost-effective free-space optics and high-Q RF components are described, along with related practical implementation issues. These components are rapidly becoming essential for enabling the development of progressive new communications systems technologies including all-optical networks, and low cost multi-system wireless terminals and basestations.

[Communication and citizenship empowerment in health care: a case of action-research in a polarized Venezuela].

PubMed

Nahón Serfaty, Isaac; Eid, Mahmoud

2015-07-01

An action-research project was implemented in Venezuela from 2009-2013 to empower social activists and patients in their fight against breast cancer (BC). The project was implemented in a context of high political and social polarization of the so-called «Bolivarian revolution». Based on an ecological perspective of health activism and communication, that encompasses the interpersonal, group and social levels, a series of activities were celebrated to develop the advocacy capabilities of citizens, especially women, expand the collaborative networks among different stakeholders, and promote a consensual view between social and institutional actors about a national response to fight BC. A horizontal and participatory communication allowed that the voice of usually marginalized actors was heard in the process of shaping health care policy.

Simple Peer-to-Peer SIP Privacy

NASA Astrophysics Data System (ADS)

Koskela, Joakim; Tarkoma, Sasu

In this paper, we introduce a model for enhancing privacy in peer-to-peer communication systems. The model is based on data obfuscation, preventing intermediate nodes from tracking calls, while still utilizing the shared resources of the peer network. This increases security when moving between untrusted, limited and ad-hoc networks, when the user is forced to rely on peer-to-peer schemes. The model is evaluated using a Host Identity Protocol-based prototype on mobile devices, and is found to provide good privacy, especially when combined with a source address hiding scheme. The contribution of this paper is to present the model and results obtained from its use, including usability considerations.

Analytical performance assessment of orbital configurations

NASA Astrophysics Data System (ADS)

Hitzl, D. L.; Krakowski, D. C.

1981-08-01

The system analysis of an orbital communication network of N satellites has been conducted. Specifically, the problem of connecting, in an optimal way, a set of ground-based laser transmitters to a second set of ground receivers on another part of the earth via a number of relay satellites fitted with retroreflectors has been addressed. A computer program has been developed which can treat either the so-called 'single-bounce' or 'double-bounce' cases. Sample results included in this paper consider a double-bounce orbital network composed of 12 relay satellites in 6 hour elliptical orbits together with 16 transceiver (delivery) satellites in 4.8 hour elliptical orbits.

High-performance, scalable optical network-on-chip architectures

NASA Astrophysics Data System (ADS)

Tan, Xianfang

The rapid advance of technology enables a large number of processing cores to be integrated into a single chip which is called a Chip Multiprocessor (CMP) or a Multiprocessor System-on-Chip (MPSoC) design. The on-chip interconnection network, which is the communication infrastructure for these processing cores, plays a central role in a many-core system. With the continuously increasing complexity of many-core systems, traditional metallic wired electronic networks-on-chip (NoC) became a bottleneck because of the unbearable latency in data transmission and extremely high energy consumption on chip. Optical networks-on-chip (ONoC) has been proposed as a promising alternative paradigm for electronic NoC with the benefits of optical signaling communication such as extremely high bandwidth, negligible latency, and low power consumption. This dissertation focus on the design of high-performance and scalable ONoC architectures and the contributions are highlighted as follow: 1. A micro-ring resonator (MRR)-based Generic Wavelength-routed Optical Router (GWOR) is proposed. A method for developing any sized GWOR is introduced. GWOR is a scalable non-blocking ONoC architecture with simple structure, low cost and high power efficiency compared to existing ONoC designs. 2. To expand the bandwidth and improve the fault tolerance of the GWOR, a redundant GWOR architecture is designed by cascading different type of GWORs into one network. 3. The redundant GWOR built with MRR-based comb switches is proposed. Comb switches can expand the bandwidth while keep the topology of GWOR unchanged by replacing the general MRRs with comb switches. 4. A butterfly fat tree (BFT)-based hybrid optoelectronic NoC (HONoC) architecture is developed in which GWORs are used for global communication and electronic routers are used for local communication. The proposed HONoC uses less numbers of electronic routers and links than its counterpart of electronic BFT-based NoC. It takes the advantages of GWOR in optical communication and BFT in non-uniform traffic communication and three-dimension (3D) implementation. 5. A cycle-accurate NoC simulator is developed to evaluate the performance of proposed HONoC architectures. It is a comprehensive platform that can simulate both electronic and optical NoCs. Different size HONoC architectures are evaluated in terms of throughput, latency and energy dissipation. Simulation results confirm that HONoC achieves good network performance with lower power consumption.

Network and user interface for PAT DOME virtual motion environment system

NASA Technical Reports Server (NTRS)

Worthington, J. W.; Duncan, K. M.; Crosier, W. G.

1993-01-01

The Device for Orientation and Motion Environments Preflight Adaptation Trainer (DOME PAT) provides astronauts a virtual microgravity sensory environment designed to help alleviate tye symptoms of space motion sickness (SMS). The system consists of four microcomputers networked to provide real time control, and an image generator (IG) driving a wide angle video display inside a dome structure. The spherical display demands distortion correction. The system is currently being modified with a new graphical user interface (GUI) and a new Silicon Graphics IG. This paper will concentrate on the new GUI and the networking scheme. The new GUI eliminates proprietary graphics hardware and software, and instead makes use of standard and low cost PC video (CGA) and off the shelf software (Microsoft's Quick C). Mouse selection for user input is supported. The new Silicon Graphics IG requires an Ethernet interface. The microcomputer known as the Real Time Controller (RTC), which has overall control of the system and is written in Ada, was modified to use the free public domain NCSA Telnet software for Ethernet communications with the Silicon Graphics IG. The RTC also maintains the original ARCNET communications through Novell Netware IPX with the rest of the system. The Telnet TCP/IP protocol was first used for real-time communication, but because of buffering problems the Telnet datagram (UDP) protocol needed to be implemented. Since the Telnet modules are written in C, the Adap pragma 'Interface' was used to interface with the network calls.

Echolocation calls and communication calls are controlled differentially in the brainstem of the bat Phyllostomus discolor

PubMed Central

Fenzl, Thomas; Schuller, Gerd

2005-01-01

Background Echolocating bats emit vocalizations that can be classified either as echolocation calls or communication calls. Neural control of both types of calls must govern the same pool of motoneurons responsible for vocalizations. Electrical microstimulation in the periaqueductal gray matter (PAG) elicits both communication and echolocation calls, whereas stimulation of the paralemniscal area (PLA) induces only echolocation calls. In both the PAG and the PLA, the current thresholds for triggering natural vocalizations do not habituate to stimuli and remain low even for long stimulation periods, indicating that these structures have relative direct access to the final common pathway for vocalization. This study intended to clarify whether echolocation calls and communication calls are controlled differentially below the level of the PAG via separate vocal pathways before converging on the motoneurons used in vocalization. Results Both structures were probed simultaneously in a single experimental approach. Two stimulation electrodes were chronically implanted within the PAG in order to elicit either echolocation or communication calls. Blockade of the ipsilateral PLA site with iontophoretically application of the glutamate antagonist kynurenic acid did not impede either echolocation or communication calls elicited from the PAG. However, blockade of the contralateral PLA suppresses PAG-elicited echolocation calls but not communication calls. In both cases the blockade was reversible. Conclusion The neural control of echolocation and communication calls seems to be differentially organized below the level of the PAG. The PLA is an essential functional unit for echolocation call control before the descending pathways share again the final common pathway for vocalization. PMID:16053533

Satellite-Based EMI Detection, Identification, and Mitigation

NASA Astrophysics Data System (ADS)

Stottler, R.; Bowman, C.

2016-09-01

Commanding, controlling, and maintaining the health of satellites requires a clear operating spectrum for communications. Electro Magnetic Interference (EMI) from other satellites can interfere with these communications. Determining which satellite is at fault improves space situational awareness and can be used to avoid the problem in the future. The Rfi detection And Prediction Tool, Optimizing Resources (RAPTOR) monitors the satellite communication antenna signals to detect EMI (also called RFI for Radio Frequency Interference) using a neural network trained on past cases of both normal communications and EMI events. RAPTOR maintains a database of satellites that have violated the reserved spectrum in the past. When satellite-based EMI is detected, RAPTOR first checks this list to determine if any are angularly close to the satellite being communicated with. Additionally, RAPTOR checks the Space Catalog to see if any of its active satellites are angularly close. RAPTOR also consults on-line databases to determine if the described operating frequencies of the satellites match the detected EMI and recommends candidates to be added to the known offenders database, accordingly. Based on detected EMI and predicted orbits and frequencies, RAPTOR automatically reschedules satellite communications to avoid current and future satellite-based EMI. It also includes an intuitive display for a global network of satellite communications antennas and their statuses including the status of their EM spectrum. RAPTOR has been prototyped and tested with real data (amplitudes versus frequency over time) for both satellite communication signals and is currently undergoing full-scale development. This paper describes the RAPTOR technologies and results of testing.

Establishing a Lessons Learned Program

DTIC Science & Technology

2011-06-01

effectively. In the future, social networking sites similar to Facebook, Twitter, and LinkedIn may provide additional capability to share lessons if they...will know if you mean it or not. Give weekly updates and use the power of social media to communicate to consumers about the progress your company...our Soldiers in Iraq and Afghanistan today. With that said, the intent of this handbook is not to explain how CALL does business . Rather, it takes a

Medium Access Control in Ad Hoc Networks With Omni-Directional and Directional Antennas

DTIC Science & Technology

2004-06-01

Carvalho, Marc, Hong, Long, Yong, Zhenjiang, Lei, Ravi, Saro, Hari, Ramesh, Brad, Renato and Radhika) in the Computer Communication Research Group (CCRG...which we call directional collision avoidance protocols. Ko et al. [35] propose two schemes. One scheme consists of nodes using directional RTS...different from the model assumed by Ko et al. [35] where antennas are always active for re- ceiving and thus transmissions to different antennas

Re-thinking risk communication: information needs of patients, health professionals and the public regarding MRSA--the communicative behaviour of a public health network in Germany responding to the demand for information.

PubMed

Dickmann, P; Wittgens, K; Keeping, S; Mischler, D; Heudorf, U

2016-02-01

Multidrug resistant organisms (MDRO), including Meticillin-resistant Staphylococcus aureus (MRSA), and health care associated infections (HCAIs) are pressing issues for health care systems across the world. Information and communication are considered key tools for the prevention and management of infectious diseases. Public Health Authorities (PHA) are in a unique position to communicate with health care professionals, patients and the public regarding the health risks. We used PHA helpdesk interaction data to first ascertain the information requirements of those getting in contact with the service, and secondly to examine the communicative behaviour of the PHA, with a view to improving the quality of communication strategies. Data on helpdesk interactions between 2010 and 2012 were obtained from a MDRO network of nine German PHAs. 501 recordings were coded and descriptive statistics generated for further qualitative thematic analysis. Our analysis revealed a similar pattern of questions among different groups. Key areas of need for information were around eradication, cleaning and isolation measures. Reported problems were a lack of expert knowledge and continuity of treatment. The helpdesk response was mainly a conversation offering scientific advice, but also included other communication services that went beyond the provision of scientific facts, such as follow-up calls, referral suggestions and consultations on behalf of the caller. These social communication activities seem to have an important impact on the acceptability of public health recommendations and use of the helpdesk. Our findings support a broader discussion about the role of information in the communication process and underline the importance of social elements in the communication process, such as relationship and trust building. Copyright © 2015 The Royal Society for Public Health. Published by Elsevier Ltd. All rights reserved.

Distributed Clone Detection in Static Wireless Sensor Networks: Random Walk with Network Division

PubMed Central

Khan, Wazir Zada; Aalsalem, Mohammed Y.; Saad, N. M.

2015-01-01

Wireless Sensor Networks (WSNs) are vulnerable to clone attacks or node replication attacks as they are deployed in hostile and unattended environments where they are deprived of physical protection, lacking physical tamper-resistance of sensor nodes. As a result, an adversary can easily capture and compromise sensor nodes and after replicating them, he inserts arbitrary number of clones/replicas into the network. If these clones are not efficiently detected, an adversary can be further capable to mount a wide variety of internal attacks which can emasculate the various protocols and sensor applications. Several solutions have been proposed in the literature to address the crucial problem of clone detection, which are not satisfactory as they suffer from some serious drawbacks. In this paper we propose a novel distributed solution called Random Walk with Network Division (RWND) for the detection of node replication attack in static WSNs which is based on claimer-reporter-witness framework and combines a simple random walk with network division. RWND detects clone(s) by following a claimer-reporter-witness framework and a random walk is employed within each area for the selection of witness nodes. Splitting the network into levels and areas makes clone detection more efficient and the high security of witness nodes is ensured with moderate communication and memory overheads. Our simulation results show that RWND outperforms the existing witness node based strategies with moderate communication and memory overheads. PMID:25992913

If it walks like a duck: nanosensor threat assessment

NASA Astrophysics Data System (ADS)

Chachis, George C.

2003-09-01

A convergence of technologies is making deployment of unattended ground nanosensors operationally feasible in terms of energy, communications for both arbitrated and self-organizing distributed, collective behaviors. A number of nano communications technologies are already making network-centric systems possible for MicroElectrical Mechanical (MEM) sensor devices today. Similar technologies may make NanoElectrical Mechanical (NEM) sensor devices operationally feasible a few years from now. Just as organizational behaviors of large numbers of nanodevices can derive strategies from social insects and other group-oriented animals, bio-inspired heuristics for threat assessment provide a conceptual approach for successful integration of nanosensors into unattended smart sensor networks. Biological models such as the organization of social insects or the dynamics of immune systems show promise as biologically-inspired paradigms for protecting nanosensor networks for security scene analysis and battlespace awareness. The paradox of nanosensors is that the smaller the device is the more useful it is but the smaller it is the more vulnerable it is to a variety of threats. In other words simpler means networked nanosensors are more likely to fall prey to a wide-range of attacks including jamming, spoofing, Janisserian recruitment, Pied-Piper distraction, as well as typical attacks computer network security. Thus, unattended sensor technologies call for network architectures that include security and countermeasures to provide reliable scene analysis or battlespace awareness information. Such network centric architectures may well draw upon a variety of bio-inspired approaches to safeguard, validate and make sense of large quantities of information.

Thin Watts-Strogatz networks.

PubMed

de Moura, Alessandro P S

2006-01-01

A modified version of the Watts-Strogatz (WS) network model is proposed, in which the number of shortcuts scales with the network size N as Nalpha, with alpha < 1. In these networks, the ratio of the number of shortcuts to the network size approaches zero as N --> infinity, whereas in the original WS model, this ratio is constant. We call such networks "thin Watts-Strogatz networks." We show that even though the fraction of shortcuts becomes vanishingly small for large networks, they still cause a kind of small-world effect, in the sense that the length L of the network increases sublinearly with the size. We develop a mean-field theory for these networks, which predicts that the length scales as N1-alpha ln N for large N. We also study how a search using only local information works in thin WS networks. We find that the search performance is enhanced compared to the regular network, and we predict that the search time tau scales as N1-alpha/2. These theoretical results are tested using numerical simulations. We comment on the possible relevance of thin WS networks for the design of high-performance low-cost communication networks.

A Proposed Neurological Interpretation of Language Evolution.

PubMed

Ardila, Alfredo

2015-01-01

Since the very beginning of the aphasia history it has been well established that there are two major aphasic syndromes (Wernicke's-type and Broca's-type aphasia); each one of them is related to the disturbance at a specific linguistic level (lexical/semantic and grammatical) and associated with a particular brain damage localization (temporal and frontal-subcortical). It is proposed that three stages in language evolution could be distinguished: (a) primitive communication systems similar to those observed in other animals, including nonhuman primates; (b) initial communication systems using sound combinations (lexicon) but without relationships among the elements (grammar); and (c) advanced communication systems including word-combinations (grammar). It is proposed that grammar probably originated from the internal representation of actions, resulting in the creation of verbs; this is an ability that depends on the so-called Broca's area and related brain networks. It is suggested that grammar is the basic ability for the development of so-called metacognitive executive functions. It is concluded that while the lexical/semantic language system (vocabulary) probably appeared during human evolution long before the contemporary man (Homo sapiens sapiens), the grammatical language historically represents a recent acquisition and is correlated with the development of complex cognition (metacognitive executive functions).

A Proposed Neurological Interpretation of Language Evolution

PubMed Central

2015-01-01

Since the very beginning of the aphasia history it has been well established that there are two major aphasic syndromes (Wernicke's-type and Broca's-type aphasia); each one of them is related to the disturbance at a specific linguistic level (lexical/semantic and grammatical) and associated with a particular brain damage localization (temporal and frontal-subcortical). It is proposed that three stages in language evolution could be distinguished: (a) primitive communication systems similar to those observed in other animals, including nonhuman primates; (b) initial communication systems using sound combinations (lexicon) but without relationships among the elements (grammar); and (c) advanced communication systems including word-combinations (grammar). It is proposed that grammar probably originated from the internal representation of actions, resulting in the creation of verbs; this is an ability that depends on the so-called Broca's area and related brain networks. It is suggested that grammar is the basic ability for the development of so-called metacognitive executive functions. It is concluded that while the lexical/semantic language system (vocabulary) probably appeared during human evolution long before the contemporary man (Homo sapiens sapiens), the grammatical language historically represents a recent acquisition and is correlated with the development of complex cognition (metacognitive executive functions). PMID:26124540

Information and communication technology in disease surveillance, India: a case study

PubMed Central

2010-01-01

India has made appreciable progress and continues to demonstrate a strong commitment for establishing and operating a disease surveillance programme responsive to the requirements of the International Health Regulations (IHR[2005]). Within five years of its launch, India has effectively used modern information and communication technology for collection, storage, transmission and management of data related to disease surveillance and effective response. Terrestrial and/or satellite based linkages are being established within all states, districts, state-run medical colleges, infectious disease hospitals, and public health laboratories. This network enables speedy data transfer, video conferencing, training and e-learning for outbreaks and programme monitoring. A 24x7 call centre is in operation to receive disease alerts. To complement these efforts, a media scanning and verification cell functions to receive reports of early warning signals. During the 2009 H1N1 outbreak, the usefulness of the information and communication technology (ICT) network was well appreciated. India is using ICT as part of its Integrated Disease Surveillance Project (IDSP) to help overcome the challenges in further expansion in hard-to-reach populations, to increase the involvement of the private sector, and to increase the use of other modes of communication like e-mail and voicemail. PMID:21143821

Complex Conjugated certificateless-based signcryption with differential integrated factor for secured message communication in mobile network

PubMed Central

Rajagopalan, S. P.

2017-01-01

Certificateless-based signcryption overcomes inherent shortcomings in traditional Public Key Infrastructure (PKI) and Key Escrow problem. It imparts efficient methods to design PKIs with public verifiability and cipher text authenticity with minimum dependency. As a classic primitive in public key cryptography, signcryption performs validity of cipher text without decryption by combining authentication, confidentiality, public verifiability and cipher text authenticity much more efficiently than the traditional approach. In this paper, we first define a security model for certificateless-based signcryption called, Complex Conjugate Differential Integrated Factor (CC-DIF) scheme by introducing complex conjugates through introduction of the security parameter and improving secured message distribution rate. However, both partial private key and secret value changes with respect to time. To overcome this weakness, a new certificateless-based signcryption scheme is proposed by setting the private key through Differential (Diff) Equation using an Integration Factor (DiffEIF), minimizing computational cost and communication overhead. The scheme is therefore said to be proven secure (i.e. improving the secured message distributing rate) against certificateless access control and signcryption-based scheme. In addition, compared with the three other existing schemes, the CC-DIF scheme has the least computational cost and communication overhead for secured message communication in mobile network. PMID:29040290

Complex Conjugated certificateless-based signcryption with differential integrated factor for secured message communication in mobile network.

PubMed

Alagarsamy, Sumithra; Rajagopalan, S P

2017-01-01

Certificateless-based signcryption overcomes inherent shortcomings in traditional Public Key Infrastructure (PKI) and Key Escrow problem. It imparts efficient methods to design PKIs with public verifiability and cipher text authenticity with minimum dependency. As a classic primitive in public key cryptography, signcryption performs validity of cipher text without decryption by combining authentication, confidentiality, public verifiability and cipher text authenticity much more efficiently than the traditional approach. In this paper, we first define a security model for certificateless-based signcryption called, Complex Conjugate Differential Integrated Factor (CC-DIF) scheme by introducing complex conjugates through introduction of the security parameter and improving secured message distribution rate. However, both partial private key and secret value changes with respect to time. To overcome this weakness, a new certificateless-based signcryption scheme is proposed by setting the private key through Differential (Diff) Equation using an Integration Factor (DiffEIF), minimizing computational cost and communication overhead. The scheme is therefore said to be proven secure (i.e. improving the secured message distributing rate) against certificateless access control and signcryption-based scheme. In addition, compared with the three other existing schemes, the CC-DIF scheme has the least computational cost and communication overhead for secured message communication in mobile network.

[Facebook in oncology. Review of the literature].

PubMed

Veneroni, Laura; Ferrari, Andrea; Massimino, Maura; Clerici, Carlo Alfredo

2015-01-01

Internet and particularly the so-called Web 2.0 are powerful tools of communication characterized by high user participation in the creation of content through various sites, such as those of social networking, where Facebook is the best known and most widely used. The aim of the present paper is to review the literature on the use of Facebook in health care. The international scientific literature of the past 10 years has been collected by major databases online. From the research were identified 262 articles of which 57 are considered relevant. The articles are schematically divided into three categories according to the topic: use of Facebook for psychosocial support for communication, for doctor-patient relationship, for institutional communication. The authors have identified the critical aspects and the possibility of using this tool in the communication and relationship between patients and health professionals. Despite the presence of critical issues, the use of social media is to be considered with interest and is worthy of study and research in the clinical setting. It should at the same time that health professionals are aware of the risks associated with the use of social networking but also trained in the use of the potential of these virtual tools that cannot replace real interactions but can support them.

Capacity-Delay Trade-Off in Collaborative Hybrid Ad-Hoc Networks with Coverage Sensing.

PubMed

Chen, Lingyu; Luo, Wenbin; Liu, Chen; Hong, Xuemin; Shi, Jianghong

2017-01-26

The integration of ad hoc device-to-device (D2D) communications and open-access small cells can result in a networking paradigm called hybrid the ad hoc network, which is particularly promising in delivering delay-tolerant data. The capacity-delay performance of hybrid ad hoc networks has been studied extensively under a popular framework called scaling law analysis. These studies, however, do not take into account aspects of interference accumulation and queueing delay and, therefore, may lead to over-optimistic results. Moreover, focusing on the average measures, existing works fail to give finer-grained insights into the distribution of delays. This paper proposes an alternative analytical framework based on queueing theoretic models and physical interference models. We apply this framework to study the capacity-delay performance of a collaborative cellular D2D network with coverage sensing and two-hop relay. The new framework allows us to fully characterize the delay distribution in the transform domain and pinpoint the impacts of coverage sensing, user and base station densities, transmit power, user mobility and packet size on the capacity-delay trade-off. We show that under the condition of queueing equilibrium, the maximum throughput capacity per device saturates to an upper bound of 0.7239 λ b / λ u bits/s/Hz, where λ b and λ u are the densities of base stations and mobile users, respectively.

Capacity-Delay Trade-Off in Collaborative Hybrid Ad-Hoc Networks with Coverage Sensing

PubMed Central

Chen, Lingyu; Luo, Wenbin; Liu, Chen; Hong, Xuemin; Shi, Jianghong

2017-01-01

The integration of ad hoc device-to-device (D2D) communications and open-access small cells can result in a networking paradigm called hybrid the ad hoc network, which is particularly promising in delivering delay-tolerant data. The capacity-delay performance of hybrid ad hoc networks has been studied extensively under a popular framework called scaling law analysis. These studies, however, do not take into account aspects of interference accumulation and queueing delay and, therefore, may lead to over-optimistic results. Moreover, focusing on the average measures, existing works fail to give finer-grained insights into the distribution of delays. This paper proposes an alternative analytical framework based on queueing theoretic models and physical interference models. We apply this framework to study the capacity-delay performance of a collaborative cellular D2D network with coverage sensing and two-hop relay. The new framework allows us to fully characterize the delay distribution in the transform domain and pinpoint the impacts of coverage sensing, user and base station densities, transmit power, user mobility and packet size on the capacity-delay trade-off. We show that under the condition of queueing equilibrium, the maximum throughput capacity per device saturates to an upper bound of 0.7239 λb/λu bits/s/Hz, where λb and λu are the densities of base stations and mobile users, respectively. PMID:28134769

Forum: Communication Activism Pedagogy. A Call for an Ethic of Transformation in Communication Activism Education

ERIC Educational Resources Information Center

Artz, Lee

2017-01-01

Lawrence Frey and David Palmer present a provocative call for communication education and research that is urgent and opportune in this forum's stimulus essay, "Communication Activism Pedagogy and Research: Communication Education Scholarship to Promote Social Justice." The call is urgent because the global human condition--including…

Speaker identification for the improvement of the security communication between law enforcement units

NASA Astrophysics Data System (ADS)

Tovarek, Jaromir; Partila, Pavol

2017-05-01

This article discusses the speaker identification for the improvement of the security communication between law enforcement units. The main task of this research was to develop the text-independent speaker identification system which can be used for real-time recognition. This system is designed for identification in the open set. It means that the unknown speaker can be anyone. Communication itself is secured, but we have to check the authorization of the communication parties. We have to decide if the unknown speaker is the authorized for the given action. The calls are recorded by IP telephony server and then these recordings are evaluate using classification If the system evaluates that the speaker is not authorized, it sends a warning message to the administrator. This message can detect, for example a stolen phone or other unusual situation. The administrator then performs the appropriate actions. Our novel proposal system uses multilayer neural network for classification and it consists of three layers (input layer, hidden layer, and output layer). A number of neurons in input layer corresponds with the length of speech features. Output layer then represents classified speakers. Artificial Neural Network classifies speech signal frame by frame, but the final decision is done over the complete record. This rule substantially increases accuracy of the classification. Input data for the neural network are a thirteen Mel-frequency cepstral coefficients, which describe the behavior of the vocal tract. These parameters are the most used for speaker recognition. Parameters for training, testing and validation were extracted from recordings of authorized users. Recording conditions for training data correspond with the real traffic of the system (sampling frequency, bit rate). The main benefit of the research is the system developed for text-independent speaker identification which is applied to secure communication between law enforcement units.

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

Dorier, Matthieu; Mubarak, Misbah; Ross, Rob

Two-tiered direct network topologies such as Dragonflies have been proposed for future post-petascale and exascale machines, since they provide a high-radix, low-diameter, fast interconnection network. Such topologies call for redesigning MPI collective communication algorithms in order to attain the best performance. Yet as increasingly more applications share a machine, it is not clear how these topology-aware algorithms will react to interference with concurrent jobs accessing the same network. In this paper, we study three topology-aware broadcast algorithms, including one designed by ourselves. We evaluate their performance through event-driven simulation for small- and large-sized broadcasts (in terms of both data sizemore » and number of processes). We study the effect of different routing mechanisms on the topology-aware collective algorithms, as well as their sensitivity to network contention with other jobs. Our results show that while topology-aware algorithms dramatically reduce link utilization, their advantage in terms of latency is more limited.« less

Experimental violation of local causality in a quantum network.

PubMed

Carvacho, Gonzalo; Andreoli, Francesco; Santodonato, Luca; Bentivegna, Marco; Chaves, Rafael; Sciarrino, Fabio

2017-03-16

Bell's theorem plays a crucial role in quantum information processing and thus several experimental investigations of Bell inequalities violations have been carried out over the years. Despite their fundamental relevance, however, previous experiments did not consider an ingredient of relevance for quantum networks: the fact that correlations between distant parties are mediated by several, typically independent sources. Here, using a photonic setup, we investigate a quantum network consisting of three spatially separated nodes whose correlations are mediated by two distinct sources. This scenario allows for the emergence of the so-called non-bilocal correlations, incompatible with any local model involving two independent hidden variables. We experimentally witness the emergence of this kind of quantum correlations by violating a Bell-like inequality under the fair-sampling assumption. Our results provide a proof-of-principle experiment of generalizations of Bell's theorem for networks, which could represent a potential resource for quantum communication protocols.

Experimental violation of local causality in a quantum network

PubMed Central

Carvacho, Gonzalo; Andreoli, Francesco; Santodonato, Luca; Bentivegna, Marco; Chaves, Rafael; Sciarrino, Fabio

2017-01-01

Bell's theorem plays a crucial role in quantum information processing and thus several experimental investigations of Bell inequalities violations have been carried out over the years. Despite their fundamental relevance, however, previous experiments did not consider an ingredient of relevance for quantum networks: the fact that correlations between distant parties are mediated by several, typically independent sources. Here, using a photonic setup, we investigate a quantum network consisting of three spatially separated nodes whose correlations are mediated by two distinct sources. This scenario allows for the emergence of the so-called non-bilocal correlations, incompatible with any local model involving two independent hidden variables. We experimentally witness the emergence of this kind of quantum correlations by violating a Bell-like inequality under the fair-sampling assumption. Our results provide a proof-of-principle experiment of generalizations of Bell's theorem for networks, which could represent a potential resource for quantum communication protocols. PMID:28300068

Experimental violation of local causality in a quantum network

NASA Astrophysics Data System (ADS)

Carvacho, Gonzalo; Andreoli, Francesco; Santodonato, Luca; Bentivegna, Marco; Chaves, Rafael; Sciarrino, Fabio

2017-03-01

Bell's theorem plays a crucial role in quantum information processing and thus several experimental investigations of Bell inequalities violations have been carried out over the years. Despite their fundamental relevance, however, previous experiments did not consider an ingredient of relevance for quantum networks: the fact that correlations between distant parties are mediated by several, typically independent sources. Here, using a photonic setup, we investigate a quantum network consisting of three spatially separated nodes whose correlations are mediated by two distinct sources. This scenario allows for the emergence of the so-called non-bilocal correlations, incompatible with any local model involving two independent hidden variables. We experimentally witness the emergence of this kind of quantum correlations by violating a Bell-like inequality under the fair-sampling assumption. Our results provide a proof-of-principle experiment of generalizations of Bell's theorem for networks, which could represent a potential resource for quantum communication protocols.

The equipment access software for a distributed UNIX-based accelerator control system

NASA Astrophysics Data System (ADS)

Trofimov, Nikolai; Zelepoukine, Serguei; Zharkov, Eugeny; Charrue, Pierre; Gareyte, Claire; Poirier, Hervé

1994-12-01

This paper presents a generic equipment access software package for a distributed control system using computers with UNIX or UNIX-like operating systems. The package consists of three main components, an application Equipment Access Library, Message Handler and Equipment Data Base. An application task, which may run in any computer in the network, sends requests to access equipment through Equipment Library calls. The basic request is in the form Equipment-Action-Data and is routed via a remote procedure call to the computer to which the given equipment is connected. In this computer the request is received by the Message Handler. According to the type of the equipment connection, the Message Handler either passes the request to the specific process software in the same computer or forwards it to a lower level network of equipment controllers using MIL1553B, GPIB, RS232 or BITBUS communication. The answer is then returned to the calling application. Descriptive information required for request routing and processing is stored in the real-time Equipment Data Base. The package has been written to be portable and is currently available on DEC Ultrix, LynxOS, HPUX, XENIX, OS-9 and Apollo domain.

47 CFR 80.369 - Distress, urgency, safety, call and reply frequencies.

Code of Federal Regulations, 2010 CFR

2010-10-01

... assignable to maritime stations for distress, urgency, safety, call and reply radiotelephony communications... by Alaska private fixed stations for calling and listening, but only for establishing communication... public coast stations for call and reply communications. The paired ship frequencies are available for...

One-Time URL: A Proximity Security Mechanism between Internet of Things and Mobile Devices

PubMed Central

Solano, Antonio; Dormido, Raquel; Duro, Natividad; González, Víctor

2016-01-01

The aim of this paper is to determine the physical proximity of connected things when they are accessed from a smartphone. Links between connected things and mobile communication devices are temporarily created by means of dynamic URLs (uniform resource locators) which may be easily discovered with pervasive short-range radio frequency technologies available on smartphones. In addition, a multi cross domain silent logging mechanism to allow people to interact with their surrounding connected things from their mobile communication devices is presented. The proposed mechanisms are based in web standards technologies, evolving our social network of Internet of Things towards the so-called Web of Things. PMID:27754378

Energy Logic (EL): a novel fusion engine of multi-modality multi-agent data/information fusion for intelligent surveillance systems

NASA Astrophysics Data System (ADS)

Rababaah, Haroun; Shirkhodaie, Amir

2009-04-01

The rapidly advancing hardware technology, smart sensors and sensor networks are advancing environment sensing. One major potential of this technology is Large-Scale Surveillance Systems (LS3) especially for, homeland security, battlefield intelligence, facility guarding and other civilian applications. The efficient and effective deployment of LS3 requires addressing number of aspects impacting the scalability of such systems. The scalability factors are related to: computation and memory utilization efficiency, communication bandwidth utilization, network topology (e.g., centralized, ad-hoc, hierarchical or hybrid), network communication protocol and data routing schemes; and local and global data/information fusion scheme for situational awareness. Although, many models have been proposed to address one aspect or another of these issues but, few have addressed the need for a multi-modality multi-agent data/information fusion that has characteristics satisfying the requirements of current and future intelligent sensors and sensor networks. In this paper, we have presented a novel scalable fusion engine for multi-modality multi-agent information fusion for LS3. The new fusion engine is based on a concept we call: Energy Logic. Experimental results of this work as compared to a Fuzzy logic model strongly supported the validity of the new model and inspired future directions for different levels of fusion and different applications.

Zone-Based Routing Protocol for Wireless Sensor Networks

PubMed Central

Venkateswarlu Kumaramangalam, Muni; Adiyapatham, Kandasamy; Kandasamy, Chandrasekaran

2014-01-01

Extensive research happening across the globe witnessed the importance of Wireless Sensor Network in the present day application world. In the recent past, various routing algorithms have been proposed to elevate WSN network lifetime. Clustering mechanism is highly successful in conserving energy resources for network activities and has become promising field for researches. However, the problem of unbalanced energy consumption is still open because the cluster head activities are tightly coupled with role and location of a particular node in the network. Several unequal clustering algorithms are proposed to solve this wireless sensor network multihop hot spot problem. Current unequal clustering mechanisms consider only intra- and intercluster communication cost. Proper organization of wireless sensor network into clusters enables efficient utilization of limited resources and enhances lifetime of deployed sensor nodes. This paper considers a novel network organization scheme, energy-efficient edge-based network partitioning scheme, to organize sensor nodes into clusters of equal size. Also, it proposes a cluster-based routing algorithm, called zone-based routing protocol (ZBRP), for elevating sensor network lifetime. Experimental results show that ZBRP out-performs interims of network lifetime and energy conservation with its uniform energy consumption among the cluster heads. PMID:27437455

Zone-Based Routing Protocol for Wireless Sensor Networks.

PubMed

Venkateswarlu Kumaramangalam, Muni; Adiyapatham, Kandasamy; Kandasamy, Chandrasekaran

2014-01-01

Extensive research happening across the globe witnessed the importance of Wireless Sensor Network in the present day application world. In the recent past, various routing algorithms have been proposed to elevate WSN network lifetime. Clustering mechanism is highly successful in conserving energy resources for network activities and has become promising field for researches. However, the problem of unbalanced energy consumption is still open because the cluster head activities are tightly coupled with role and location of a particular node in the network. Several unequal clustering algorithms are proposed to solve this wireless sensor network multihop hot spot problem. Current unequal clustering mechanisms consider only intra- and intercluster communication cost. Proper organization of wireless sensor network into clusters enables efficient utilization of limited resources and enhances lifetime of deployed sensor nodes. This paper considers a novel network organization scheme, energy-efficient edge-based network partitioning scheme, to organize sensor nodes into clusters of equal size. Also, it proposes a cluster-based routing algorithm, called zone-based routing protocol (ZBRP), for elevating sensor network lifetime. Experimental results show that ZBRP out-performs interims of network lifetime and energy conservation with its uniform energy consumption among the cluster heads.

A Sustained Proximity Network for Multi-Mission Lunar Exploration

NASA Technical Reports Server (NTRS)

Soloff, Jason A.; Noreen, Gary; Deutsch, Leslie; Israel, David

2005-01-01

Tbe Vision for Space Exploration calls for an aggressive sequence of robotic missions beginning in 2008 to prepare for a human return to the Moon by 2020, with the goal of establishing a sustained human presence beyond low Earth orbit. A key enabler of exploration is reliable, available communication and navigation capabilities to support both human and robotic missions. An adaptable, sustainable communication and navigation architecture has been developed by Goddard Space Flight Center and the Jet Propulsion Laboratory to support human and robotic lunar exploration through the next two decades. A key component of the architecture is scalable deployment, with the infrastructure evolving as needs emerge, allowing NASA and its partner agencies to deploy an interoperable communication and navigation system in an evolutionary way, enabling cost effective, highly adaptable systems throughout the lunar exploration program.

Distributed Multihoming Routing Method by Crossing Control MIPv6 with SCTP

NASA Astrophysics Data System (ADS)

Shi, Hongbo; Hamagami, Tomoki

There are various wireless communication technologies, such as 3G, WiFi, used widely in the world. Recently, not only the laptop but also the smart phones can be equipped with multiple wireless devices. The communication terminals which are implemented with multiple interfaces are usually called multi-homed nodes. Meanwhile, a multi-homed node with multiple interfaces can also be regarded as multiple single-homed nodes. For example, when a person who is using smart phone and laptop to connect to the Internet concurrently, we may regard the person as a multi-homed node in the Internet. This paper proposes a new routing method, Multi-homed Mobile Cross-layer Control to handle multi-homed mobile nodes. Our suggestion can provide a distributed end-to-end routing method for handling the communications among multi-homed nodes at the fundamental network layer.

A Case for Open Network Health Systems: Systems as Networks in Public Mental Health.

PubMed

Rhodes, Michael Grant; de Vries, Marten W

2017-01-08

Increases in incidents involving so-called confused persons have brought attention to the potential costs of recent changes to public mental health (PMH) services in the Netherlands. Decentralized under the (Community) Participation Act (2014), local governments must find resources to compensate for reduced central funding to such services or "innovate." But innovation, even when pressure for change is intense, is difficult. This perspective paper describes experience during and after an investigation into a particularly violent incident and murder. The aim was to provide recommendations to improve the functioning of local PMH services. The investigation concluded that no specific failure by an individual professional or service provider facility led to the murder. Instead, also as a result of the Participation Act that severed communication lines between individuals and organizations, information sharing failures were likely to have reduced system level capacity to identify risks. The methods and analytical frameworks employed to reach this conclusion, also lead to discussion as to the plausibility of an unconventional solution. If improving communication is the primary problem, non-hierarchical information, and organizational networks arise as possible and innovative system solutions. The proposal for debate is that traditional "health system" definitions, literature and narratives, and operating assumptions in public (mental) health are 'locked in' constraining technical and organization innovations. If we view a "health system" as an adaptive system of economic and social "networks," it becomes clear that the current orthodox solution, the so-called integrated health system, typically results in a "centralized hierarchical" or "tree" network. An overlooked alternative that breaks out of the established policy narratives is the view of a 'health systems' as a non-hierarchical organizational structure or 'Open Network.' In turn, this opens new technological and organizational possibilities in seeking policy solutions, and suggests an alternative governance model of huge potential value in public health both locally and globally. © 2017 The Author(s); Published by Kerman University of Medical Sciences. This is an open-access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

The Study on the Communication Network of Wide Area Measurement System in Electricity Grid

NASA Astrophysics Data System (ADS)

Xiaorong, Cheng; Ying, Wang; Yangdan, Ni

Wide area measurement system(WAMS) is a fundamental part of security defense in Smart Grid, and the communication system of WAMS is an important part of Electric power communication network. For a large regional network is concerned, the real-time data which is transferred in the communication network of WAMS will affect the safe operation of the power grid directly. Therefore, WAMS raised higher requirements for real-time, reliability and security to its communication network. In this paper, the architecture of WASM communication network was studied according to the seven layers model of the open systems interconnection(OSI), and the network architecture was researched from all levels. We explored the media of WAMS communication network, the network communication protocol and network technology. Finally, the delay of the network were analyzed.

Measurement and Modeling of Narrowband Channels for Ultrasonic Underwater Communications

PubMed Central

Cañete, Francisco J.; López-Fernández, Jesús; García-Corrales, Celia; Sánchez, Antonio; Robles, Encarnación; Rodrigo, Francisco J.; Paris, José F.

2016-01-01

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. PMID:26907281

Image processing for navigation on a mobile embedded platform

NASA Astrophysics Data System (ADS)

Preuss, Thomas; Gentsch, Lars; Rambow, Mark

2006-02-01

Mobile computing devices such as PDAs or cellular phones may act as "Personal Multimedia Exchanges", but they are limited in their processing power as well as in their connectivity. Sensors as well as cellular phones and PDAs are able to gather multimedia data, e. g. images, but leak computing power to process that data on their own. Therefore, it is necessary, that these devices connect to devices with more performance, which provide e.g. image processing services. In this paper, a generic approach is presented that connects different kinds of clients with each other and allows them to interact with more powerful devices. This architecture, called BOSPORUS, represents a communication framework for dynamic peer-to-peer computing. Each peer offers and uses services in this network and communicates loosely coupled and asynchronously with the others. These features make BOSPORUS a service oriented network architecture (SONA). A mobile embedded system, which uses external services for image processing based on the BOSPORUS Framework is shown as an application of the BOSPORUS framework.

Classifier fusion for VoIP attacks classification

NASA Astrophysics Data System (ADS)

Safarik, Jakub; Rezac, Filip

2017-05-01

SIP is one of the most successful protocols in the field of IP telephony communication. It establishes and manages VoIP calls. As the number of SIP implementation rises, we can expect a higher number of attacks on the communication system in the near future. This work aims at malicious SIP traffic classification. A number of various machine learning algorithms have been developed for attack classification. The paper presents a comparison of current research and the use of classifier fusion method leading to a potential decrease in classification error rate. Use of classifier combination makes a more robust solution without difficulties that may affect single algorithms. Different voting schemes, combination rules, and classifiers are discussed to improve the overall performance. All classifiers have been trained on real malicious traffic. The concept of traffic monitoring depends on the network of honeypot nodes. These honeypots run in several networks spread in different locations. Separation of honeypots allows us to gain an independent and trustworthy attack information.

Project Connect Online: Randomized Trial of an Internet-Based Program to Chronicle the Cancer Experience and Facilitate Communication

PubMed Central

Stanton, Annette L.; Thompson, Elizabeth H.; Crespi, Catherine M.; Link, John S.; Waisman, James R.

2013-01-01

Purpose Evidence suggests that expressing emotions related to cancer and receiving interpersonal support can promote psychological and physical health in women diagnosed with breast cancer. However, adaptive expression of feelings and communication with one's social network can pose challenges for patients with cancer. We report on a randomized controlled trial of an intervention, Project Connect Online, for patients with breast cancer to create personal Web sites to chronicle their experience and communicate with their social network. Patients and Methods Women (N = 88) diagnosed with breast cancer (any stage, any interval since diagnosis) were randomly assigned to participate in a 3-hour workshop for hands-on creation of personal Web sites with a follow-up call to facilitate Web site use, or to a waiting-list control. Assessed before randomization and 6 months after the intervention, dependent variables included depressive symptoms, positive and negative mood, cancer-related intrusive thoughts, and perceived cancer-related benefits in life appreciation and strengthened relationships. Results Relative to control participants, women randomly assigned to Project Connect Online evidenced significant benefit 6 months later on depressive symptoms, positive mood, and life appreciation, but not negative mood, perceived strengthened relationships, or intrusive thoughts. Treatment status moderated the intervention effects, such that women currently undergoing medical treatment for cancer benefitted significantly more from the intervention on depressive symptoms and positive mood than did women not receiving treatment. Conclusion Findings suggest the promise of an intervention to facilitate the ability of women diagnosed with breast cancer to chronicle their experience and communicate with their social network via the Internet. PMID:23940228

Project connect online: randomized trial of an internet-based program to chronicle the cancer experience and facilitate communication.

PubMed

Stanton, Annette L; Thompson, Elizabeth H; Crespi, Catherine M; Link, John S; Waisman, James R

2013-09-20

Evidence suggests that expressing emotions related to cancer and receiving interpersonal support can promote psychological and physical health in women diagnosed with breast cancer. However, adaptive expression of feelings and communication with one's social network can pose challenges for patients with cancer. We report on a randomized controlled trial of an intervention, Project Connect Online, for patients with breast cancer to create personal Web sites to chronicle their experience and communicate with their social network. Women (N = 88) diagnosed with breast cancer (any stage, any interval since diagnosis) were randomly assigned to participate in a 3-hour workshop for hands-on creation of personal Web sites with a follow-up call to facilitate Web site use, or to a waiting-list control. Assessed before randomization and 6 months after the intervention, dependent variables included depressive symptoms, positive and negative mood, cancer-related intrusive thoughts, and perceived cancer-related benefits in life appreciation and strengthened relationships. Relative to control participants, women randomly assigned to Project Connect Online evidenced significant benefit 6 months later on depressive symptoms, positive mood, and life appreciation, but not negative mood, perceived strengthened relationships, or intrusive thoughts. Treatment status moderated the intervention effects, such that women currently undergoing medical treatment for cancer benefitted significantly more from the intervention on depressive symptoms and positive mood than did women not receiving treatment. Findings suggest the promise of an intervention to facilitate the ability of women diagnosed with breast cancer to chronicle their experience and communicate with their social network via the Internet.

On IEEE 802.15.6 IR-UWB receivers - simulations for DBPSK modulation.

PubMed

Niemelä, Ville; Hämäläinen, Matti; Iinatti, Jari

2013-01-01

In 2002, Federal Communications Commission (FCC) was the first in defining regulations for ultra wideband (UWB) communications followed by Europe and Japan some years later. Focusing on impulse radio (IR) UWB, in 2007 was the time for the first published standard targeting in personal area networks, released by the IEEE. The second IEEE released standard including UWB definitions is targeted for wireless body area networks (WBAN) and was published in 2012. As the wireless communications has been and will be passing through almost any levels in society, the natural step with WBAN is using it in different medical, healthcare and wellbeing applications. The arguments for these are related to the modern lifestyle, in which people have increasingly more free time and are more interested in taking care of their health and wellbeing. Another challenge is the population composition, i.e., aging in developed countries which call for new solutions and procedures, particularly from cost wise. In this paper, we are evaluating UWB receivers based on the IEEE 802.15.6 physical layer definitions and capable of detecting differentially encoded modulation. The evaluation is performed using two different WBAN channel models.

Multiple-Ring Digital Communication Network

NASA Technical Reports Server (NTRS)

Kirkham, Harold

1992-01-01

Optical-fiber digital communication network to support data-acquisition and control functions of electric-power-distribution networks. Optical-fiber links of communication network follow power-distribution routes. Since fiber crosses open power switches, communication network includes multiple interconnected loops with occasional spurs. At each intersection node is needed. Nodes of communication network include power-distribution substations and power-controlling units. In addition to serving data acquisition and control functions, each node acts as repeater, passing on messages to next node(s). Multiple-ring communication network operates on new AbNET protocol and features fiber-optic communication.

[Information system of the national network of public health laboratories in Peru (Netlab)].

PubMed

Vargas-Herrera, Javier; Segovia-Juarez, José; Garro Nuñez, Gladys María

2015-01-01

Clinical laboratory information systems produce improvements in the quality of information, reduce service costs, and diminish wait times for results, among other things. In the construction process of this information system, the National Institute of Health (NIH) of Peru has developed and implemented a web-based application to communicate to health personnel (laboratory workers, epidemiologists, health strategy managers, physicians, etc.) the results of laboratory tests performed at the Peruvian NIH or in the laboratories of the National Network of Public Health Laboratories which is called NETLAB. This article presents the experience of implementing NETLAB, its current situation, perspectives of its use, and its contribution to the prevention and control of diseases in Peru.

QoS-Oriented High Dynamic Resource Allocation in Vehicular Communication Networks

PubMed Central

2014-01-01

Vehicular ad hoc networks (VANETs) are emerging as new research area and attracting an increasing attention from both industry and research communities. In this context, a dynamic resource allocation policy that maximizes the use of available resources and meets the quality of service (QoS) requirement of constraining applications is proposed. It is a combination of a fair packet scheduling policy and a new adaptive QoS oriented call admission control (CAC) scheme based on the vehicle density variation. This scheme decides whether the connection request is to be admitted into the system, while providing fair access and guaranteeing the desired throughput. The proposed algorithm showed good performance in testing in real world environment. PMID:24616639

The North Warning System: A Canadian military SATCOM success

NASA Astrophysics Data System (ADS)

Wawryk, Ivan J.

The strategic threat to North America presented by modern, supersonic bombers and long range cruise missiles has stimulated a modernization of atmospheric defence capability. The North Warning System (NWS), employs a chain of microwave radars across the Arctic and down the east coast of Canada to provide tactical warning and attack assessment information to NORAD and its forces. The responsibility for NWS facilities construction and communications is allocated to Canada. Earlier investigations in Canada and the U.S. had confirmed that an all satellite communications system to link the 47 Canadian NWS radars to command and control centers was more economical than any terrestrial alternative. A project was undertaken by the Canadian Department of National Defence (DND) to acquire and install an integrated, digital satellite communications system for the NWS. This paper outlines the project background and procurement process. System requirements and specifications are discussed and the communications system is described in some detail. The communications equipment will be required to function unmanned in extreme Arctic conditions for extended periods. Specifications called for a long haul communications network (LHCN), a maintenance control system to monitor and control the equipment, and a suite of on-site communications for each location. The LHCN is a fully integrated, redundant satellite system which employs a transponder on each of the Anik D satellites. Either transponder can carry the full communications load. The system is configured as a star network with the hub at North Bay. Five remote stations and the North Bay facility have been built in phase one of the project; the second phase will see the construction of 36 unattended stations across the Arctic and down the Baffin Island and Labrador coasts.

Butterfly Encryption Scheme for Resource-Constrained Wireless Networks †

PubMed Central

Sampangi, Raghav V.; Sampalli, Srinivas

2015-01-01

Resource-constrained wireless networks are emerging networks such as Radio Frequency Identification (RFID) and Wireless Body Area Networks (WBAN) that might have restrictions on the available resources and the computations that can be performed. These emerging technologies are increasing in popularity, particularly in defence, anti-counterfeiting, logistics and medical applications, and in consumer applications with growing popularity of the Internet of Things. With communication over wireless channels, it is essential to focus attention on securing data. In this paper, we present an encryption scheme called Butterfly encryption scheme. We first discuss a seed update mechanism for pseudorandom number generators (PRNG), and employ this technique to generate keys and authentication parameters for resource-constrained wireless networks. Our scheme is lightweight, as in it requires less resource when implemented and offers high security through increased unpredictability, owing to continuously changing parameters. Our work focuses on accomplishing high security through simplicity and reuse. We evaluate our encryption scheme using simulation, key similarity assessment, key sequence randomness assessment, protocol analysis and security analysis. PMID:26389899

The brain as a system of nested but partially overlapping networks. Heuristic relevance of the model for brain physiology and pathology.

PubMed

Agnati, L F; Guidolin, D; Fuxe, K

2007-01-01

A new model of the brain organization is proposed. The model is based on the assumption that a global molecular network enmeshes the entire central nervous system. Thus, brain extra-cellular and intra-cellular molecular networks are proposed to communicate at the level of special plasma membrane regions (e.g., the lipid rafts) where horizontal molecular networks can represent input/output regions allowing the cell to have informational exchanges with the extracellular environment. Furthermore, some "pervasive signals" such as field potentials, pressure waves and thermal gradients that affect large parts of the brain cellular and molecular networks are discussed. Finally, at least two learning paradigms are analyzed taking into account the possible role of Volume Transmission: the so-called model of "temporal difference learning" and the "Turing B-unorganised machine". The relevance of this new view of brain organization for a deeper understanding of some neurophysiological and neuropathological aspects of its function is briefly discussed.

Butterfly Encryption Scheme for Resource-Constrained Wireless Networks.

PubMed

Sampangi, Raghav V; Sampalli, Srinivas

2015-09-15

Resource-constrained wireless networks are emerging networks such as Radio Frequency Identification (RFID) and Wireless Body Area Networks (WBAN) that might have restrictions on the available resources and the computations that can be performed. These emerging technologies are increasing in popularity, particularly in defence, anti-counterfeiting, logistics and medical applications, and in consumer applications with growing popularity of the Internet of Things. With communication over wireless channels, it is essential to focus attention on securing data. In this paper, we present an encryption scheme called Butterfly encryption scheme. We first discuss a seed update mechanism for pseudorandom number generators (PRNG), and employ this technique to generate keys and authentication parameters for resource-constrained wireless networks. Our scheme is lightweight, as in it requires less resource when implemented and offers high security through increased unpredictability, owing to continuously changing parameters. Our work focuses on accomplishing high security through simplicity and reuse. We evaluate our encryption scheme using simulation, key similarity assessment, key sequence randomness assessment, protocol analysis and security analysis.

GLOBECOM '89 - IEEE Global Telecommunications Conference and Exhibition, Dallas, TX, Nov. 27-30, 1989, Conference Record. Volumes 1, 2, & 3

NASA Astrophysics Data System (ADS)

The present conference discusses topics in multiwavelength network technology and its applications, advanced digital radio systems in their propagation environment, mobile radio communications, switching programmability, advancements in computer communications, integrated-network management and security, HDTV and image processing in communications, basic exchange communications radio advancements in digital switching, intelligent network evolution, speech coding for telecommunications, and multiple access communications. Also discussed are network designs for quality assurance, recent progress in coherent optical systems, digital radio applications, advanced communications technologies for mobile users, communication software for switching systems, AI and expert systems in network management, intelligent multiplexing nodes, video and image coding, network protocols and performance, system methods in quality and reliability, the design and simulation of lightwave systems, local radio networks, mobile satellite communications systems, fiber networks restoration, packet video networks, human interfaces for future networks, and lightwave networking.

The Dynamics of Initiative in Communication Networks.

PubMed

Mollgaard, Anders; Mathiesen, Joachim

2016-01-01

Human social interaction is often intermittent. Two acquainted persons can have extended periods without social interaction punctuated by periods of repeated interaction. In this case, the repeated interaction can be characterized by a seed initiative by either of the persons and a number of follow-up interactions. The tendency to initiate social interaction plays an important role in the formation of social networks and is in general not symmetric between persons. In this paper, we study the dynamics of initiative by analysing and modeling a detailed call and text message network sampled from a group of 700 individuals. We show that in an average relationship between two individuals, one part is almost twice as likely to initiate communication compared to the other part. The asymmetry has social consequences and ultimately might lead to the discontinuation of a relationship. We explain the observed asymmetry by a positive feedback mechanism where individuals already taking initiative are more likely to take initiative in the future. In general, people with many initiatives receive attention from a broader spectrum of friends than people with few initiatives. Lastly, we compare the likelihood of taking initiative with the basic personality traits of the five factor model.

Perspectives of Nurses on Patients With Limited English Proficiency and Their Call Light Use.

PubMed

Galinato, Jose; Montie, Mary; Shuman, Clayton; Patak, Lance; Titler, Marita

2016-08-12

Patients use call light systems to initiate communication with their health care team. Little is known how this process is affected when language barriers exist between an English-speaking nurse and a patient with limited English proficiency (LEP). The aims of this study are to describe (a) the perceptions of nurses regarding their communication with patients with LEP, (b) how call lights affect their communication with patients with LEP, and (c) the perceptions of nurses on the impact of advancement in call light technology on patients with LEP. Using focus groups, nurses were asked about their interactions with patients with LEP. The following themes emerged: barriers to communication, formal tools for communication, gestures and charades, reliance on family, creating a better call light system, and acceptability of Eloquence™. This results show that call lights affect the interaction of nurses with patients with LEP and complex issues arise in the subsequent communication that is initiated by the call light.

Perspectives of Nurses on Patients With Limited English Proficiency and Their Call Light Use

PubMed Central

Galinato, Jose; Montie, Mary; Shuman, Clayton; Patak, Lance; Titler, Marita

2016-01-01

Patients use call light systems to initiate communication with their health care team. Little is known how this process is affected when language barriers exist between an English-speaking nurse and a patient with limited English proficiency (LEP). The aims of this study are to describe (a) the perceptions of nurses regarding their communication with patients with LEP, (b) how call lights affect their communication with patients with LEP, and (c) the perceptions of nurses on the impact of advancement in call light technology on patients with LEP. Using focus groups, nurses were asked about their interactions with patients with LEP. The following themes emerged: barriers to communication, formal tools for communication, gestures and charades, reliance on family, creating a better call light system, and acceptability of Eloquence™. This results show that call lights affect the interaction of nurses with patients with LEP and complex issues arise in the subsequent communication that is initiated by the call light. PMID:28393085

Analysis and Application of Microgrids

NASA Astrophysics Data System (ADS)

Yue, Lu

New trends of generating electricity locally and utilizing non-conventional or renewable energy sources have attracted increasing interests due to the gradual depletion of conventional fossil fuel energy sources. The new type of power generation is called Distributed Generation (DG) and the energy sources utilized by Distributed Generation are termed Distributed Energy Sources (DERs). With DGs embedded in the distribution networks, they evolve from passive distribution networks to active distribution networks enabling bidirectional power flows in the networks. Further incorporating flexible and intelligent controllers and employing future technologies, active distribution networks will turn to a Microgrid. A Microgrid is a small-scale, low voltage Combined with Heat and Power (CHP) supply network designed to supply electrical and heat loads for a small community. To further implement Microgrids, a sophisticated Microgrid Management System must be integrated. However, due to the fact that a Microgrid has multiple DERs integrated and is likely to be deregulated, the ability to perform real-time OPF and economic dispatch with fast speed advanced communication network is necessary. In this thesis, first, problems such as, power system modelling, power flow solving and power system optimization, are studied. Then, Distributed Generation and Microgrid are studied and reviewed, including a comprehensive review over current distributed generation technologies and Microgrid Management Systems, etc. Finally, a computer-based AC optimization method which minimizes the total transmission loss and generation cost of a Microgrid is proposed and a wireless communication scheme based on synchronized Code Division Multiple Access (sCDMA) is proposed. The algorithm is tested with a 6-bus power system and a 9-bus power system.

Dimensions and dynamics of citizen observatories: The case of online amateur weather networks

NASA Astrophysics Data System (ADS)

Gharesifard, Mohammad; Wehn, Uta; van der Zaag, Pieter

2016-04-01

Crowd-sourced environmental observations are being increasingly considered as having the potential to enhance the spatial and temporal resolution of current data streams from terrestrial and areal sensors. The rapid diffusion of ICTs during the past decades has facilitated the process of data collection and sharing by the general public (so-called citizen science) and has resulted in the formation of various online environmental citizen observatory networks. Online amateur weather networks are a particular example of such ICT-mediated citizen observatories as one of the oldest and most widely practiced citizen science activities. The objective of this paper is to introduce a conceptual framework that enables a systematic review of different dimensions of these mushrooming/expanding networks. These dimensions include the geographic scope and types of network participants; the network's establishment mechanism, revenue stream(s) and existing communication paradigm; efforts required by citizens and support offered by platform providers; and issues such as data accessibility, availability and quality. An in-depth understanding of these dimensions helps to analyze various dynamics such as interactions between different stakeholders, motivations to run these networks, sustainability of the platforms, data ownership and level of transparency of each network. This framework is then utilized to perform a critical and normative review of six existing online amateur weather networks based on publicly available data. The main findings of this analysis suggest that: (1) There are several key stakeholders such as emergency services and local authorities that are not (yet) engaged in these networks. (2) The revenue stream(s) of online amateur weather networks is one of the least discussed but most important dimensions that is crucial for the sustainability of these networks. (3) Although all of the networks included in this study have one or more explicit pattern of two-way communications, there is no sign (yet) of interactive information exchange among the triangle of weather observers, data aggregators and policy makers. KEYWORDS Citizen Science, Citizen Observatories, ICT-enabled citizen participation, online amateur weather networks

Evidence That Calls-Based and Mobility Networks Are Isomorphic

PubMed Central

Coscia, Michele; Hausmann, Ricardo

2015-01-01

Social relations involve both face-to-face interaction as well as telecommunications. We can observe the geography of phone calls and of the mobility of cell phones in space. These two phenomena can be described as networks of connections between different points in space. We use a dataset that includes billions of phone calls made in Colombia during a six-month period. We draw the two networks and find that the call-based network resembles a higher order aggregation of the mobility network and that both are isomorphic except for a higher spatial decay coefficient of the mobility network relative to the call-based network: when we discount distance effects on the call connections with the same decay observed for mobility connections, the two networks are virtually indistinguishable. PMID:26713730

Applications to determine the shortest tower BTS distance using Dijkstra algorithm

NASA Astrophysics Data System (ADS)

Mardana, Herwin; Maharani, Septya; Hatta, Heliza Rahmania

2017-02-01

Telecommunications Tower or so-called BTS (Base Transceiver System) Toweris one of the main components in the network infrastructure that has experienced an increase in the number of construction. Telecommunications tower function as a place to put the antenna signal transmitter (access network) to provide communication services to customers around the tower. In addition, other use of telecommunications tower also to place the transmission signal antenna (transport network using microwave technology) for connecting customers with a central area. Therefore, in needed of a decision support system that can provide recommendations planting route of fiber optic cable with the shortest distance in purpose the use of fiber optic cable becoming more efficient. The results of the research were the shortest rule information, showing the distance to be travelled and the map view to enabling users to look at these.

Development concepts of a Smart Cyber Operating Theater (SCOT) using ORiN technology.

PubMed

Okamoto, Jun; Masamune, Ken; Iseki, Hiroshi; Muragaki, Yoshihiro

2018-02-23

Currently, networking has not progressed in the treatment room. Almost every medical device in the treatment room operates as a stand-alone device. In this project, we aim to develop a networked operating room called "Smart Cyber Operating Theater (SCOT)". Medical devices are connected using Open Resource interface for the Network (ORiN) technology. In this paper, we describe the concept of the SCOT project. SCOT is integrated using the communication interface ORiN, which was originally developed for industry. One feature of ORiN is that the system can be constructed flexibly. ORiN creates abstracts of the same type of devices and increases the robustness of the system for device exchange. By using ORiN technology, we are developing new applications, such as decision-making navigation or a precision guided treatment system.

Exploiting Publication Contents and Collaboration Networks for Collaborator Recommendation

PubMed Central

Kong, Xiangjie; Jiang, Huizhen; Yang, Zhuo; Xu, Zhenzhen; Xia, Feng; Tolba, Amr

2016-01-01

Thanks to the proliferation of online social networks, it has become conventional for researchers to communicate and collaborate with each other. Meanwhile, one critical challenge arises, that is, how to find the most relevant and potential collaborators for each researcher? In this work, we propose a novel collaborator recommendation model called CCRec, which combines the information on researchers’ publications and collaboration network to generate better recommendation. In order to effectively identify the most potential collaborators for researchers, we adopt a topic clustering model to identify the academic domains, as well as a random walk model to compute researchers’ feature vectors. Using DBLP datasets, we conduct benchmarking experiments to examine the performance of CCRec. The experimental results show that CCRec outperforms other state-of-the-art methods in terms of precision, recall and F1 score. PMID:26849682

GLOBECOM '86 - Global Telecommunications Conference, Houston, TX, Dec. 1-4, 1986, Conference Record. Volumes 1, 2, & 3

NASA Astrophysics Data System (ADS)

Papers are presented on local area networks; formal methods for communication protocols; computer simulation of communication systems; spread spectrum and coded communications; tropical radio propagation; VLSI for communications; strategies for increasing software productivity; multiple access communications; advanced communication satellite technologies; and spread spectrum systems. Topics discussed include Space Station communication and tracking development and design; transmission networks; modulation; data communications; computer network protocols and performance; and coding and synchronization. Consideration is given to free space optical communications systems; VSAT communication networks; network topology design; advances in adaptive filtering echo cancellation and adaptive equalization; advanced signal processing for satellite communications; the elements, design, and analysis of fiber-optic networks; and advances in digital microwave systems.

A Study of Quality of Service Communication for High-Speed Packet-Switching Computer Sub-Networks

NASA Technical Reports Server (NTRS)

Cui, Zhenqian

1999-01-01

With the development of high-speed networking technology, computer networks, including local-area networks (LANs), wide-area networks (WANs) and the Internet, are extending their traditional roles of carrying computer data. They are being used for Internet telephony, multimedia applications such as conferencing and video on demand, distributed simulations, and other real-time applications. LANs are even used for distributed real-time process control and computing as a cost-effective approach. Differing from traditional data transfer, these new classes of high-speed network applications (video, audio, real-time process control, and others) are delay sensitive. The usefulness of data depends not only on the correctness of received data, but also the time that data are received. In other words, these new classes of applications require networks to provide guaranteed services or quality of service (QoS). Quality of service can be defined by a set of parameters and reflects a user's expectation about the underlying network's behavior. Traditionally, distinct services are provided by different kinds of networks. Voice services are provided by telephone networks, video services are provided by cable networks, and data transfer services are provided by computer networks. A single network providing different services is called an integrated-services network.

The Spatial Properties of Radical Environmental Organizations in the UK: Do or Die!

PubMed Central

2016-01-01

Radical environmental groups and their members have a wide and varied agenda which often encompasses both local and global issues. In their efforts to call attention to environmental problems, communicate with like-minded groups, and mobilize support for their activities, radical environmental organizations also produce an enormous amount of text, which can be used to estimate the complex communications and task-based networks that underlie these organizations. Moreover, the tactics employed to garnish attention for these groups’ agenda can range from peaceful activities such as information dissemination to violent activities such as fire-bombing buildings. To obtain these varied objectives, radical environmental organizations must harness their networks, which have an important spatial component that structures their ability to communicate, coordinate and act on any given agenda item. Here, we analyze a network built from communications and information provided by the semi-annual “Do or Die” (DoD) magazine published in the UK over a 10 year period in the late 1990s and early 2000s. We first employ structural topic model methods to discover violent and nonviolent actors within the larger environmental community. Using this designation, we then compare the spatial structure of these groups, finding that violent groups are especially likely to engage in coordination and/or communication if they are sufficiently close, but exhibit a quickly decreasing probability of interaction over even a few kilometers. Further, violent and nonviolent groups each have a higher probability of coordination with their own group than across groups over even short distances. In these respects, we see that violent groups are especially local in their organization and that their geographic reach is likely very limited. This suggests that nonviolent environmental groups seek each other out over both large and short distances for communication and coordination, but violent groups tend to be highly localized. PMID:27898689

The Spatial Properties of Radical Environmental Organizations in the UK: Do or Die!

PubMed

Almquist, Zack W; Bagozzi, Benjamin E

2016-01-01

Radical environmental groups and their members have a wide and varied agenda which often encompasses both local and global issues. In their efforts to call attention to environmental problems, communicate with like-minded groups, and mobilize support for their activities, radical environmental organizations also produce an enormous amount of text, which can be used to estimate the complex communications and task-based networks that underlie these organizations. Moreover, the tactics employed to garnish attention for these groups' agenda can range from peaceful activities such as information dissemination to violent activities such as fire-bombing buildings. To obtain these varied objectives, radical environmental organizations must harness their networks, which have an important spatial component that structures their ability to communicate, coordinate and act on any given agenda item. Here, we analyze a network built from communications and information provided by the semi-annual "Do or Die" (DoD) magazine published in the UK over a 10 year period in the late 1990s and early 2000s. We first employ structural topic model methods to discover violent and nonviolent actors within the larger environmental community. Using this designation, we then compare the spatial structure of these groups, finding that violent groups are especially likely to engage in coordination and/or communication if they are sufficiently close, but exhibit a quickly decreasing probability of interaction over even a few kilometers. Further, violent and nonviolent groups each have a higher probability of coordination with their own group than across groups over even short distances. In these respects, we see that violent groups are especially local in their organization and that their geographic reach is likely very limited. This suggests that nonviolent environmental groups seek each other out over both large and short distances for communication and coordination, but violent groups tend to be highly localized.

An Optimal Method for Detecting Internal and External Intrusion in MANET

NASA Astrophysics Data System (ADS)

Rafsanjani, Marjan Kuchaki; Aliahmadipour, Laya; Javidi, Mohammad M.

Mobile Ad hoc Network (MANET) is formed by a set of mobile hosts which communicate among themselves through radio waves. The hosts establish infrastructure and cooperate to forward data in a multi-hop fashion without a central administration. Due to their communication type and resources constraint, MANETs are vulnerable to diverse types of attacks and intrusions. In this paper, we proposed a method for prevention internal intruder and detection external intruder by using game theory in mobile ad hoc network. One optimal solution for reducing the resource consumption of detection external intruder is to elect a leader for each cluster to provide intrusion service to other nodes in the its cluster, we call this mode moderate mode. Moderate mode is only suitable when the probability of attack is low. Once the probability of attack is high, victim nodes should launch their own IDS to detect and thwart intrusions and we call robust mode. In this paper leader should not be malicious or selfish node and must detect external intrusion in its cluster with minimum cost. Our proposed method has three steps: the first step building trust relationship between nodes and estimation trust value for each node to prevent internal intrusion. In the second step we propose an optimal method for leader election by using trust value; and in the third step, finding the threshold value for notifying the victim node to launch its IDS once the probability of attack exceeds that value. In first and third step we apply Bayesian game theory. Our method due to using game theory, trust value and honest leader can effectively improve the network security, performance and reduce resource consumption.

Cost Consideration for Future Communications Satellite

NASA Astrophysics Data System (ADS)

Iida, Takashi

2002-01-01

This paper discusses the cost driving factors of the future communications satellite rather than discussing its cost itself directly, in terms of development period of time, services, and R&D by government. In the first, a period of time for development of a communications system is discussed in comparison of satellite communications system with a terrestrial communications system. Generally speaking, the terrestrial communications system is developed in a short period. Especially, the recent network related IT technology changes very rapidly, like so-called as "Dog Year". On the other hand, it takes a long time, more than several years, to develop a satellite communications system. This paper will discuss this time period of development is how to influence the system realization in various cases. In the second, the service related cost is discussed. First, a mobile communications satellite system is considered as an example. The tremendous penetration speed of the terrestrial cellular phones prevents from the success of the mobile satellite communications system. The success of the mobile satellite communications system depends on how early and user friendly to develop its user terminals. Second, the broadcasting service is described as a successful example. It is described that the satellite broadcasting has a very competitive advantage to the terrestrial broadcasting service from the cost point of view. Finally, the cost of the technology R&D for the future communication satellite by the government is discussed. A model of the future communications satellite for next 30 years has been proposed(1)(2). As an example, this paper estimates the satellite cost of the 60 Gbps range of capacity which is called as 1.5G satellite, where the capacity of the second generation Internet satellite (2G) is 50-500 Gbps per satellite. In the paper, the R&D plan of the future communications satellite will be discussed as a next R&D project to the first generation Internet satellite from a cost point of view. References (1)T.Iida and Y.Suzuki: "Satellite Communications R&D for Next 30 Years", 19th AIAA (2)T.Iida, Y.Suzuki and A.Akaishi: "Satellite Communications R&D for Next 30 Years:

Research on key technology of space laser communication network

NASA Astrophysics Data System (ADS)

Chang, Chengwu; Huang, Huiming; Liu, Hongyang; Gao, Shenghua; Cheng, Liyu

2016-10-01

Since the 21st century, Spatial laser communication has made a breakthrough development. Europe, the United States, Japan and other space powers have carried out the test of spatial laser communication technology on-orbit, and put forward a series of plans. In 2011, China made the first technology demonstration of satellite-ground laser communication carried by HY-2 satellite. Nowadays, in order to improve the transmission rate of spatial network, the topic of spatial laser communication network is becoming a research hotspot at home and abroad. This thesis, from the basic problem of spatial laser communication network to solve, analyzes the main difference between spatial network and ground network, which draws forth the key technology of spatial laser communication backbone network, and systematically introduces our research on aggregation, addressing, architecture of spatial network. From the perspective of technology development status and trends, the thesis proposes the development route of spatial laser communication network in stages. So as to provide reference about the development of spatial laser communication network in China.

Improving Reliability in a Stochastic Communication Network

DTIC Science & Technology

1990-12-01

and GINO. In addition, the following computers were used: a Sun 386i workstation, a Digital Equipment Corporation (DEC) 11/785 miniframe , and a DEC...operating system. The DEC 11/785 miniframe used in the experiment was running Unix Version 4.3 (Berkley System Domain). Maxflo was run on the DEC 11/785...the file was still called Mod- ifyl.for). 4. The Maxflo program was started on the DEC 11/785 miniframe . 5. At this time the Convert.max file, created

Communication assisted Localization and Navigation for Networked Robots

DTIC Science & Technology

2005-09-01

developments such as the Mica Mote [23, 24] and the single chip called “Spec” [1] along the path to the ultimate goal of smart dust. Other technologies...path or a path defining a grid , broadcasting GPS coordinates. The sensors incrementally pro- cess all broadcasts they receive to refine their estimated...RAM, 4K EEPROM), a 916 MHz RF transceiver (50Kbits/sec, nominal 30m range), a UART and a 4Mbit serial flash. A Mote runs for approximately one month on

Wireless Augmented Reality Communication System

NASA Technical Reports Server (NTRS)

Agan, Martin (Inventor); Devereaux, Ann (Inventor); Jedrey, Thomas (Inventor)

2015-01-01

A portable unit is for video communication to select a user name in a user name network. A transceiver wirelessly accesses a communication network through a wireless connection to a general purpose node coupled to the communication network. A user interface can receive user input to log on to a user name network through the communication network. The user name network has a plurality of user names, at least one of the plurality of user names is associated with a remote portable unit, logged on to the user name network and available for video communication.

Wireless Augmented Reality Communication System

NASA Technical Reports Server (NTRS)

Jedrey, Thomas (Inventor); Agan, Martin (Inventor); Devereaux, Ann (Inventor)

2017-01-01

A portable unit is for video communication to select a user name in a user name network. A transceiver wirelessly accesses a communication network through a wireless connection to a general purpose node coupled to the communication network. A user interface can receive user input to log on to a user name network through the communication network. The user name network has a plurality of user names, at least one of the plurality of user names is associated with a remote portable unit, logged on to the user name network and available for video communication.

29 CFR 4002.6 - Place of meetings; use of conference call communications equipment.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 29 Labor 9 2010-07-01 2010-07-01 false Place of meetings; use of conference call communications... conference call communications equipment. Meetings of the Board of Directors shall be held at the principal... may participate in a meeting of the Board of Directors through the use of conference call telephone or...

Examination of wireless technology to improve nurse communication, response time to bed alarms, and patient safety.

PubMed

Guarascio-Howard, Linda

2011-01-01

A medical-surgical unit in a southwestern United States hospital examined the results of adding wireless communication technology to assist nurses in identifying patient bed status changes and enhancing team communication. Following the addition of wireless communication, response time to patient calls and the number of nurse-initiated communications were compared to pre-wireless calls and response time sampling period. In the baseline study, nurse-initiated communications and response time to patient calls were investigated for a team nursing model (Guarascio-Howard & Malloch, 2007). At this time, technology consisted of a nurse call system and telephones located at each decentralized nurse station and health unit coordinator (HUC) station. For this follow-up study, a wireless device was given to nurses and their team members following training on device use and privacy issues. Four registered nurses (RNs) were shadowed for 8 hours (32 hours total) before and after the introduction of the wireless devices. Data were collected regarding patient room visits, number of patient calls, bed status calls, response time to calls, and the initiator of the communication episodes. Follow-up study response time to calls significantly decreased (t-test p = .03). RNs and licensed practical nurses responded to bed status calls in less than 1 minute-62% of the 37 calls. Communication results indicated a significant shift (One Proportion Z Test) in RN-initiated communications, suggesting an enhanced ability to communicate with team members and to assist in monitoring patient status. Patient falls trended downward, although not significantly (p > .05), for a 6-month period of wireless technology use compared to the same period the previous year. The addition of a wireless device has advantages in team nursing, namely increasing communication with staff members and decreasing response time to patient and bed status calls. Limitations of the study included a change in caregiver team members and issues regarding wireless device and locator badge compliance. Administrative issues that arose during this field study included bed and cable maintenance, device battery charging, and the training of new and floating team members.

Intelligentization: an efficient means to get more from optical networking

NASA Astrophysics Data System (ADS)

Chen, Zhi Yun

2001-10-01

Infocom is a term used to describe the merger of Information and Communications and is used to show the radical changes in today's network traffic. The continuous growth of Infocom traffic, especially that of Internet, is driving Infocom networks to expand rapidly. To service providers, the traffic is consuming the bandwidth of their network. Simultaneously, users are complaining too slow, the net never stopped in China. It is the reality faced by both the service providers and equipment vendors. Demands from both the customers and competition in market call for an efficient network infrastructure. What should a Service Provider do? This paper will first analyze the development trends of optical networking and the formation of the concepts of Intelligent Optical Network (ION) and Automatic Switched Optical Network (ASON) as a solution to this problem. Next it will look at the ways to bring intelligence into optical networks, discussing the benefits to service providers by showing some application examples. Finally, it concludes that the development of optical networking has arrived at a point of introducing intelligence into optical networks. The intelligent optical networks and Automatic Switched Optical Networks will immediately bring a wide range of benefit to service providers, equipment vendors, and, of course, the end users.

Conduits to care: call lights and patients' perceptions of communication.

PubMed

Montie, Mary; Shuman, Clayton; Galinato, Jose; Patak, Lance; Anderson, Christine A; Titler, Marita G

2017-01-01

Call light systems remain the primary means of hospitalized patients to initiate communication with their health care providers. Although there is vast amounts of literature discussing patient communication with their health care providers, few studies have explored patients' perceptions concerning call light use and communication. The specific aim of this study was to solicit patients' perceptions regarding their call light use and communication with nursing staff. Patients invited to this study met the following inclusion criteria: proficient in English, been hospitalized for at least 24 hours, aged ≥21 years, and able to communicate verbally (eg, not intubated). Thirty participants provided written informed consent, were enrolled in the study, and completed interviews. Using qualitative descriptive methods, five major themes emerged from patients' perceptions (namely; establishing connectivity, participant safety concerns, no separation: health care and the call light device, issues with the current call light, and participants' perceptions of "nurse work"). Multiple minor themes supported these major themes. Data analysis utilized the constant comparative methods of Glaser and Strauss. Findings from this study extend the knowledge of patients' understanding of not only why inconsistencies occur between the call light and their nurses, but also why the call light is more than merely a device to initiate communication; rather, it is a direct conduit to their health care and its delivery.

Graph Design via Convex Optimization: Online and Distributed Perspectives

NASA Astrophysics Data System (ADS)

Meng, De

Network and graph have long been natural abstraction of relations in a variety of applications, e.g. transportation, power system, social network, communication, electrical circuit, etc. As a large number of computation and optimization problems are naturally defined on graphs, graph structures not only enable important properties of these problems, but also leads to highly efficient distributed and online algorithms. For example, graph separability enables the parallelism for computation and operation as well as limits the size of local problems. More interestingly, graphs can be defined and constructed in order to take best advantage of those problem properties. This dissertation focuses on graph structure and design in newly proposed optimization problems, which establish a bridge between graph properties and optimization problem properties. We first study a new optimization problem called Geodesic Distance Maximization Problem (GDMP). Given a graph with fixed edge weights, finding the shortest path, also known as the geodesic, between two nodes is a well-studied network flow problem. We introduce the Geodesic Distance Maximization Problem (GDMP): the problem of finding the edge weights that maximize the length of the geodesic subject to convex constraints on the weights. We show that GDMP is a convex optimization problem for a wide class of flow costs, and provide a physical interpretation using the dual. We present applications of the GDMP in various fields, including optical lens design, network interdiction, and resource allocation in the control of forest fires. We develop an Alternating Direction Method of Multipliers (ADMM) by exploiting specific problem structures to solve large-scale GDMP, and demonstrate its effectiveness in numerical examples. We then turn our attention to distributed optimization on graph with only local communication. Distributed optimization arises in a variety of applications, e.g. distributed tracking and localization, estimation problems in sensor networks, multi-agent coordination. Distributed optimization aims to optimize a global objective function formed by summation of coupled local functions over a graph via only local communication and computation. We developed a weighted proximal ADMM for distributed optimization using graph structure. This fully distributed, single-loop algorithm allows simultaneous updates and can be viewed as a generalization of existing algorithms. More importantly, we achieve faster convergence by jointly designing graph weights and algorithm parameters. Finally, we propose a new problem on networks called Online Network Formation Problem: starting with a base graph and a set of candidate edges, at each round of the game, player one first chooses a candidate edge and reveals it to player two, then player two decides whether to accept it; player two can only accept limited number of edges and make online decisions with the goal to achieve the best properties of the synthesized network. The network properties considered include the number of spanning trees, algebraic connectivity and total effective resistance. These network formation games arise in a variety of cooperative multiagent systems. We propose a primal-dual algorithm framework for the general online network formation game, and analyze the algorithm performance by the competitive ratio and regret.

Remote Neural Pendants In A Welding-Control System

NASA Technical Reports Server (NTRS)

Venable, Richard A.; Bucher, Joseph H.

1995-01-01

Neural network integrated circuits enhance functionalities of both remote terminals (called "pendants") and communication links, without necessitating installation of additional wires in links. Makes possible to incorporate many features into pendant, including real-time display of critical welding parameters and other process information, capability for communication between technician at pendant and host computer or technician elsewhere in system, and switches and potentiometers through which technician at pendant exerts remote control over such critical aspects of welding process as current, voltage, rate of travel, flow of gas, starting, and stopping. Other potential manufacturing applications include control of spray coating and of curing of composite materials. Potential nonmanufacturing uses include remote control of heating, air conditioning, and lighting in electrically noisy and otherwise hostile environments.

Information spreading on mobile communication networks: A new model that incorporates human behaviors

NASA Astrophysics Data System (ADS)

Ren, Fei; Li, Sai-Ping; Liu, Chuang

2017-03-01

Recently, there is a growing interest in the modeling and simulation based on real social networks among researchers in multi-disciplines. Using an empirical social network constructed from the calling records of a Chinese mobile service provider, we here propose a new model to simulate the information spreading process. This model takes into account two important ingredients that exist in real human behaviors: information prevalence and preferential spreading. The fraction of informed nodes when the system reaches an asymptotically stable state is primarily determined by information prevalence, and the heterogeneity of link weights would slow down the information diffusion. Moreover, the sizes of blind clusters which consist of connected uninformed nodes show a power-law distribution, and these uninformed nodes correspond to a particular portion of nodes which are located at special positions in the network, namely at the edges of large clusters or inside the clusters connected through weak links. Since the simulations are performed on a real world network, the results should be useful in the understanding of the influences of social network structures and human behaviors on information propagation.

High call volume at poison control centers: identification and implications for communication

PubMed Central

CARAVATI, E. M.; LATIMER, S.; REBLIN, M.; BENNETT, H. K. W.; CUMMINS, M. R.; CROUCH, B. I.; ELLINGTON, L.

2016-01-01

Context High volume surges in health care are uncommon and unpredictable events. Their impact on health system performance and capacity is difficult to study. Objectives To identify time periods that exhibited very busy conditions at a poison control center and to determine whether cases and communication during high volume call periods are different from cases during low volume periods. Methods Call data from a US poison control center over twelve consecutive months was collected via a call logger and an electronic case database (Toxicall®). Variables evaluated for high call volume conditions were: (1) call duration; (2) number of cases; and (3) number of calls per staff member per 30 minute period. Statistical analyses identified peak periods as busier than 99% of all other 30 minute time periods and low volume periods as slower than 70% of all other 30 minute periods. Case and communication characteristics of high volume and low volume calls were compared using logistic regression. Results A total of 65,364 incoming calls occurred over 12 months. One hundred high call volume and 4885 low call volume 30 minute periods were identified. High volume periods were more common between 1500 and 2300 hours and during the winter months. Coded verbal communication data were evaluated for 42 high volume and 296 low volume calls. The mean (standard deviation) call length of these calls during high volume and low volume periods was 3 minutes 27 seconds (1 minute 46 seconds) and 3 minutes 57 seconds (2 minutes 11 seconds), respectively. Regression analyses revealed a trend for fewer overall verbal statements and fewer staff questions during peak periods, but no other significant differences for staff-caller communication behaviors were found. Conclusion Peak activity for poison center call volume can be identified by statistical modeling. Calls during high volume periods were similar to low volume calls. Communication was more concise yet staff was able to maintain a good rapport with callers during busy call periods. This approach allows evaluation of poison exposure call characteristics and communication during high volume periods. PMID:22889059

High call volume at poison control centers: identification and implications for communication.

PubMed

Caravati, E M; Latimer, S; Reblin, M; Bennett, H K W; Cummins, M R; Crouch, B I; Ellington, L

2012-09-01

High volume surges in health care are uncommon and unpredictable events. Their impact on health system performance and capacity is difficult to study. To identify time periods that exhibited very busy conditions at a poison control center and to determine whether cases and communication during high volume call periods are different from cases during low volume periods. Call data from a US poison control center over twelve consecutive months was collected via a call logger and an electronic case database (Toxicall®).Variables evaluated for high call volume conditions were: (1) call duration; (2) number of cases; and (3) number of calls per staff member per 30 minute period. Statistical analyses identified peak periods as busier than 99% of all other 30 minute time periods and low volume periods as slower than 70% of all other 30 minute periods. Case and communication characteristics of high volume and low volume calls were compared using logistic regression. A total of 65,364 incoming calls occurred over 12 months. One hundred high call volume and 4885 low call volume 30 minute periods were identified. High volume periods were more common between 1500 and 2300 hours and during the winter months. Coded verbal communication data were evaluated for 42 high volume and 296 low volume calls. The mean (standard deviation) call length of these calls during high volume and low volume periods was 3 minutes 27 seconds (1 minute 46 seconds) and 3 minutes 57 seconds (2 minutes 11 seconds), respectively. Regression analyses revealed a trend for fewer overall verbal statements and fewer staff questions during peak periods, but no other significant differences for staff-caller communication behaviors were found. Peak activity for poison center call volume can be identified by statistical modeling. Calls during high volume periods were similar to low volume calls. Communication was more concise yet staff was able to maintain a good rapport with callers during busy call periods. This approach allows evaluation of poison exposure call characteristics and communication during high volume periods.

Adaptive Suspicious Prevention for Defending DoS Attacks in SDN-Based Convergent Networks

PubMed Central

Dao, Nhu-Ngoc; Kim, Joongheon; Park, Minho; Cho, Sungrae

2016-01-01

The convergent communication network will play an important role as a single platform to unify heterogeneous networks and integrate emerging technologies and existing legacy networks. Although there have been proposed many feasible solutions, they could not become convergent frameworks since they mainly focused on converting functions between various protocols and interfaces in edge networks, and handling functions for multiple services in core networks, e.g., the Multi-protocol Label Switching (MPLS) technique. Software-defined networking (SDN), on the other hand, is expected to be the ideal future for the convergent network since it can provide a controllable, dynamic, and cost-effective network. However, SDN has an original structural vulnerability behind a lot of advantages, which is the centralized control plane. As the brains of the network, a controller manages the whole network, which is attractive to attackers. In this context, we proposes a novel solution called adaptive suspicious prevention (ASP) mechanism to protect the controller from the Denial of Service (DoS) attacks that could incapacitate an SDN. The ASP is integrated with OpenFlow protocol to detect and prevent DoS attacks effectively. Our comprehensive experimental results show that the ASP enhances the resilience of an SDN network against DoS attacks by up to 38%. PMID:27494411

Adaptive Suspicious Prevention for Defending DoS Attacks in SDN-Based Convergent Networks.

PubMed

Dao, Nhu-Ngoc; Kim, Joongheon; Park, Minho; Cho, Sungrae

2016-01-01

The convergent communication network will play an important role as a single platform to unify heterogeneous networks and integrate emerging technologies and existing legacy networks. Although there have been proposed many feasible solutions, they could not become convergent frameworks since they mainly focused on converting functions between various protocols and interfaces in edge networks, and handling functions for multiple services in core networks, e.g., the Multi-protocol Label Switching (MPLS) technique. Software-defined networking (SDN), on the other hand, is expected to be the ideal future for the convergent network since it can provide a controllable, dynamic, and cost-effective network. However, SDN has an original structural vulnerability behind a lot of advantages, which is the centralized control plane. As the brains of the network, a controller manages the whole network, which is attractive to attackers. In this context, we proposes a novel solution called adaptive suspicious prevention (ASP) mechanism to protect the controller from the Denial of Service (DoS) attacks that could incapacitate an SDN. The ASP is integrated with OpenFlow protocol to detect and prevent DoS attacks effectively. Our comprehensive experimental results show that the ASP enhances the resilience of an SDN network against DoS attacks by up to 38%.

Daily Rhythms in Mobile Telephone Communication

PubMed Central

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

2015-01-01

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

Daily Rhythms in Mobile Telephone Communication.

PubMed

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

2015-01-01

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

Performance analysis of signaling protocols on OBS switches

NASA Astrophysics Data System (ADS)

Kirci, Pinar; Zaim, A. Halim

2005-10-01

In this paper, Just-In-Time (JIT), Just-Enough-Time (JET) and Horizon signalling schemes for Optical Burst Switched Networks (OBS) are presented. These signaling schemes run over a core dWDM network and a network architecture based on Optical Burst Switches (OBS) is proposed to support IP, ATM and Burst traffic. In IP and ATM traffic several packets are assembled in a single packet called burst and the burst contention is handled by burst dropping. The burst length distribution in IP traffic is arbitrary between 0 and 1, and is fixed in ATM traffic at 0,5. Burst traffic on the other hand is arbitrary between 1 and 5. The Setup and Setup ack length distributions are arbitrary. We apply the Poisson model with rate λ and Self-Similar model with pareto distribution rate α to identify inter-arrival times in these protocols. We consider a communication between a source client node and a destination client node over an ingress and one or more multiple intermediate switches.We use buffering only in the ingress node. The communication is based on single burst connections in which, the connection is set up just before sending a burst and then closed as soon as the burst is sent. Our analysis accounts for several important parameters, including the burst setup, burst setup ack, keepalive messages and the optical switching protocol. We compare the performance of the three signalling schemes on the network under as burst dropping probability under a range of network scenarios.

Mars Comm/Nav MicroSat Network Using the Multi-Mission Bus Launched Piggyback by Ariane 5

NASA Technical Reports Server (NTRS)

Hastrup, R. C.; Cesarone, R. J.; Morabito, D. D.

1999-01-01

Recently, NASA's Jet Propulsion Laboratory completed a Mars Exploration Program Architecture Definition Study with strong international participation. The recommendations of this study include establishment of a low cost in-situ communications and navigation satellite network to provide enabling and enhancing support for the international exploration of Mars. This would be the first step toward establishing a "virtual presence throughout the solar system" as called for in NASA's Strategic Plan. Response to the proposed comm/nav satellite network has been very favorably received, as reflected by the inclusion of a line item in NASA's budget submittal to Congress, which provides funding for implementation of the network with first launch in the 2003 opportunity. Funding has already been provided for a phase A study being conducted this year. This paper presents the planned implementation of the comm/nav network, which will utilize microsats based on a multi-mission spacecraft bus being designed for launch by the Ariane 5 as a secondary payload. A companion paper at this conference, entitled "The Multi-Purpose Mars Micro-Mission System Design Utilizing Ariane 5 Piggyback Launch", describes the multimission bus design. This paper addresses the application of the multi-mission bus to the comm/nav microsat mission. Following an introduction, which provides the background that has led to the proposed comm/nav network, the paper discusses the projected user needs with emphasis on the various possible robotic missions (landers, rovers, ascent vehicles, balloons, aircraft, etc.) progressing toward eventual piloted missions. Next, the paper describes the concept for an evolving network of comm/nav microsats and the expected capability to satisfy the user needs. Results of communications and navigation performance analysis are summarized for attractive satellite constellation configurations. The important comm/nav microsat functional requirements on the multi-mission spacecraft bus are described with discussion of the mission-system tradeoffs for the driving requirements. The functional design of the in-situ communications / navigation package, which constitutes the payload of the microsat, is also described. The paper also includes discussion of technologies which are of specific importance to the implementation of the comm/nav microsat network.

Emotion shapes the diffusion of moralized content in social networks

PubMed Central

Wills, Julian A.; Jost, John T.; Tucker, Joshua A.; Van Bavel, Jay J.

2017-01-01

Political debate concerning moralized issues is increasingly common in online social networks. However, moral psychology has yet to incorporate the study of social networks to investigate processes by which some moral ideas spread more rapidly or broadly than others. Here, we show that the expression of moral emotion is key for the spread of moral and political ideas in online social networks, a process we call “moral contagion.” Using a large sample of social media communications about three polarizing moral/political issues (n = 563,312), we observed that the presence of moral-emotional words in messages increased their diffusion by a factor of 20% for each additional word. Furthermore, we found that moral contagion was bounded by group membership; moral-emotional language increased diffusion more strongly within liberal and conservative networks, and less between them. Our results highlight the importance of emotion in the social transmission of moral ideas and also demonstrate the utility of social network methods for studying morality. These findings offer insights into how people are exposed to moral and political ideas through social networks, thus expanding models of social influence and group polarization as people become increasingly immersed in social media networks. PMID:28652356

Emotion shapes the diffusion of moralized content in social networks.

PubMed

Brady, William J; Wills, Julian A; Jost, John T; Tucker, Joshua A; Van Bavel, Jay J

2017-07-11

Political debate concerning moralized issues is increasingly common in online social networks. However, moral psychology has yet to incorporate the study of social networks to investigate processes by which some moral ideas spread more rapidly or broadly than others. Here, we show that the expression of moral emotion is key for the spread of moral and political ideas in online social networks, a process we call "moral contagion." Using a large sample of social media communications about three polarizing moral/political issues ( n = 563,312), we observed that the presence of moral-emotional words in messages increased their diffusion by a factor of 20% for each additional word. Furthermore, we found that moral contagion was bounded by group membership; moral-emotional language increased diffusion more strongly within liberal and conservative networks, and less between them. Our results highlight the importance of emotion in the social transmission of moral ideas and also demonstrate the utility of social network methods for studying morality. These findings offer insights into how people are exposed to moral and political ideas through social networks, thus expanding models of social influence and group polarization as people become increasingly immersed in social media networks.

Offline Social Relationships and Online Cancer Communication: Effects of Social and Family Support on Online Social Network Building.

PubMed

Namkoong, Kang; Shah, Dhavan V; Gustafson, David H

2017-11-01

This study investigates how social support and family relationship perceptions influence breast cancer patients' online communication networks in a computer-mediated social support (CMSS) group. To examine social interactions in the CMSS group, we identified two types of online social networks: open and targeted communication networks. The open communication network reflects group communication behaviors (i.e., one-to-many or "broadcast" communication) in which the intended audience is not specified; in contrast, the targeted communication network reflects interpersonal discourses (i.e., one-to-one or directed communication) in which the audience for the message is specified. The communication networks were constructed by tracking CMSS group usage data of 237 breast cancer patients who participated in one of two National Cancer Institute-funded randomized clinical trials. Eligible subjects were within 2 months of a diagnosis of primary breast cancer or recurrence at the time of recruitment. Findings reveal that breast cancer patients who perceived less availability of offline social support had a larger social network size in the open communication network. In contrast, those who perceived less family cohesion had a larger targeted communication network in the CMSS group, meaning they were inclined to use the CMSS group for developing interpersonal relationships.

Emergent Auditory Feature Tuning in a Real-Time Neuromorphic VLSI System.

PubMed

Sheik, Sadique; Coath, Martin; Indiveri, Giacomo; Denham, Susan L; Wennekers, Thomas; Chicca, Elisabetta

2012-01-01

Many sounds of ecological importance, such as communication calls, are characterized by time-varying spectra. However, most neuromorphic auditory models to date have focused on distinguishing mainly static patterns, under the assumption that dynamic patterns can be learned as sequences of static ones. In contrast, the emergence of dynamic feature sensitivity through exposure to formative stimuli has been recently modeled in a network of spiking neurons based on the thalamo-cortical architecture. The proposed network models the effect of lateral and recurrent connections between cortical layers, distance-dependent axonal transmission delays, and learning in the form of Spike Timing Dependent Plasticity (STDP), which effects stimulus-driven changes in the pattern of network connectivity. In this paper we demonstrate how these principles can be efficiently implemented in neuromorphic hardware. In doing so we address two principle problems in the design of neuromorphic systems: real-time event-based asynchronous communication in multi-chip systems, and the realization in hybrid analog/digital VLSI technology of neural computational principles that we propose underlie plasticity in neural processing of dynamic stimuli. The result is a hardware neural network that learns in real-time and shows preferential responses, after exposure, to stimuli exhibiting particular spectro-temporal patterns. The availability of hardware on which the model can be implemented, makes this a significant step toward the development of adaptive, neurobiologically plausible, spike-based, artificial sensory systems.

Emergent Auditory Feature Tuning in a Real-Time Neuromorphic VLSI System

PubMed Central

Sheik, Sadique; Coath, Martin; Indiveri, Giacomo; Denham, Susan L.; Wennekers, Thomas; Chicca, Elisabetta

2011-01-01

Many sounds of ecological importance, such as communication calls, are characterized by time-varying spectra. However, most neuromorphic auditory models to date have focused on distinguishing mainly static patterns, under the assumption that dynamic patterns can be learned as sequences of static ones. In contrast, the emergence of dynamic feature sensitivity through exposure to formative stimuli has been recently modeled in a network of spiking neurons based on the thalamo-cortical architecture. The proposed network models the effect of lateral and recurrent connections between cortical layers, distance-dependent axonal transmission delays, and learning in the form of Spike Timing Dependent Plasticity (STDP), which effects stimulus-driven changes in the pattern of network connectivity. In this paper we demonstrate how these principles can be efficiently implemented in neuromorphic hardware. In doing so we address two principle problems in the design of neuromorphic systems: real-time event-based asynchronous communication in multi-chip systems, and the realization in hybrid analog/digital VLSI technology of neural computational principles that we propose underlie plasticity in neural processing of dynamic stimuli. The result is a hardware neural network that learns in real-time and shows preferential responses, after exposure, to stimuli exhibiting particular spectro-temporal patterns. The availability of hardware on which the model can be implemented, makes this a significant step toward the development of adaptive, neurobiologically plausible, spike-based, artificial sensory systems. PMID:22347163

An Efficient Location Verification Scheme for Static Wireless Sensor Networks.

PubMed

Kim, In-Hwan; Kim, Bo-Sung; Song, JooSeok

2017-01-24

In wireless sensor networks (WSNs), the accuracy of location information is vital to support many interesting applications. Unfortunately, sensors have difficulty in estimating their location when malicious sensors attack the location estimation process. Even though secure localization schemes have been proposed to protect location estimation process from attacks, they are not enough to eliminate the wrong location estimations in some situations. The location verification can be the solution to the situations or be the second-line defense. The problem of most of the location verifications is the explicit involvement of many sensors in the verification process and requirements, such as special hardware, a dedicated verifier and the trusted third party, which causes more communication and computation overhead. In this paper, we propose an efficient location verification scheme for static WSN called mutually-shared region-based location verification (MSRLV), which reduces those overheads by utilizing the implicit involvement of sensors and eliminating several requirements. In order to achieve this, we use the mutually-shared region between location claimant and verifier for the location verification. The analysis shows that MSRLV reduces communication overhead by 77% and computation overhead by 92% on average, when compared with the other location verification schemes, in a single sensor verification. In addition, simulation results for the verification of the whole network show that MSRLV can detect the malicious sensors by over 90% when sensors in the network have five or more neighbors.

An Efficient Location Verification Scheme for Static Wireless Sensor Networks

PubMed Central

Kim, In-hwan; Kim, Bo-sung; Song, JooSeok

2017-01-01

In wireless sensor networks (WSNs), the accuracy of location information is vital to support many interesting applications. Unfortunately, sensors have difficulty in estimating their location when malicious sensors attack the location estimation process. Even though secure localization schemes have been proposed to protect location estimation process from attacks, they are not enough to eliminate the wrong location estimations in some situations. The location verification can be the solution to the situations or be the second-line defense. The problem of most of the location verifications is the explicit involvement of many sensors in the verification process and requirements, such as special hardware, a dedicated verifier and the trusted third party, which causes more communication and computation overhead. In this paper, we propose an efficient location verification scheme for static WSN called mutually-shared region-based location verification (MSRLV), which reduces those overheads by utilizing the implicit involvement of sensors and eliminating several requirements. In order to achieve this, we use the mutually-shared region between location claimant and verifier for the location verification. The analysis shows that MSRLV reduces communication overhead by 77% and computation overhead by 92% on average, when compared with the other location verification schemes, in a single sensor verification. In addition, simulation results for the verification of the whole network show that MSRLV can detect the malicious sensors by over 90% when sensors in the network have five or more neighbors. PMID:28125007

Quick Vegas: Improving Performance of TCP Vegas for High Bandwidth-Delay Product Networks

NASA Astrophysics Data System (ADS)

Chan, Yi-Cheng; Lin, Chia-Liang; Ho, Cheng-Yuan

An important issue in designing a TCP congestion control algorithm is that it should allow the protocol to quickly adjust the end-to-end communication rate to the bandwidth on the bottleneck link. However, the TCP congestion control may function poorly in high bandwidth-delay product networks because of its slow response with large congestion windows. In this paper, we propose an enhanced version of TCP Vegas called Quick Vegas, in which we present an efficient congestion window control algorithm for a TCP source. Our algorithm improves the slow-start and congestion avoidance techniques of original Vegas. Simulation results show that Quick Vegas significantly improves the performance of connections as well as remaining fair when the bandwidth-delay product increases.

Intelsat TDMA and its implementation in Australia

NASA Astrophysics Data System (ADS)

Howe, Stuart

The developmental history and characteristics of the Intelsat digital communications network are surveyed, with a focus on the current implementation status in Australia. Topics addressed include the fundamental principles and advantages of a TDMA system, the hardware required for a TDMA traffic station, and the Intelsat Indian Ocean Primary satellite network. Detailed consideration is given to TDMA test equipment (burst-mode link analyzers, PCM DSI test sets, burst-power meters, burst negators, and reference burst generators), terminal integration with terrestrial and RF links (TWT sharing and equalization), equipment compatibility, and traffic. Plans call for 950 TDMA circuits by the end of 1990, representing about 36.5 percent of the traffic between Australia and Europe, Africa, India and Pakistan, and the Middle East.

Auditory cortex of bats and primates: managing species-specific calls for social communication

PubMed Central

Kanwal, Jagmeet S.; Rauschecker, Josef P.

2014-01-01

Individuals of many animal species communicate with each other using sounds or “calls” that are made up of basic acoustic patterns and their combinations. We are interested in questions about the processing of communication calls and their representation within the mammalian auditory cortex. Our studies compare in particular two species for which a large body of data has accumulated: the mustached bat and the rhesus monkey. We conclude that the brains of both species share a number of functional and organizational principles, which differ only in the extent to which and how they are implemented. For instance, neurons in both species use “combination-sensitivity” (nonlinear spectral and temporal integration of stimulus components) as a basic mechanism to enable exquisite sensitivity to and selectivity for particular call types. Whereas combination-sensitivity is already found abundantly at the primary auditory cortical and also at subcortical levels in bats, it becomes prevalent only at the level of the lateral belt in the secondary auditory cortex of monkeys. A parallel-hierarchical framework for processing complex sounds up to the level of the auditory cortex in bats and an organization into parallel-hierarchical, cortico-cortical auditory processing streams in monkeys is another common principle. Response specialization of neurons seems to be more pronounced in bats than in monkeys, whereas a functional specialization into “what” and “where” streams in the cerebral cortex is more pronounced in monkeys than in bats. These differences, in part, are due to the increased number and larger size of auditory areas in the parietal and frontal cortex in primates. Accordingly, the computational prowess of neural networks and the functional hierarchy resulting in specializations is established early and accelerated across brain regions in bats. The principles proposed here for the neural “management” of species-specific calls in bats and primates can be tested by studying the details of call processing in additional species. Also, computational modeling in conjunction with coordinated studies in bats and monkeys can help to clarify the fundamental question of perceptual invariance (or “constancy”) in call recognition, which has obvious relevance for understanding speech perception and its disorders in humans. PMID:17485400

Bat echolocation calls facilitate social communication

PubMed Central

Knörnschild, Mirjam; Jung, Kirsten; Nagy, Martina; Metz, Markus; Kalko, Elisabeth

2012-01-01

Bat echolocation is primarily used for orientation and foraging but also holds great potential for social communication. The communicative function of echolocation calls is still largely unstudied, especially in the wild. Eavesdropping on vocal signatures encoding social information in echolocation calls has not, to our knowledge, been studied in free-living bats so far. We analysed echolocation calls of the polygynous bat Saccopteryx bilineata and found pronounced vocal signatures encoding sex and individual identity. We showed experimentally that free-living males discriminate approaching male and female conspecifics solely based on their echolocation calls. Males always produced aggressive vocalizations when hearing male echolocation calls and courtship vocalizations when hearing female echolocation calls; hence, they responded with complex social vocalizations in the appropriate social context. Our study demonstrates that social information encoded in bat echolocation calls plays a crucial and hitherto underestimated role for eavesdropping conspecifics and thus facilitates social communication in a highly mobile nocturnal mammal. PMID:23034703

Bat echolocation calls facilitate social communication.

PubMed

Knörnschild, Mirjam; Jung, Kirsten; Nagy, Martina; Metz, Markus; Kalko, Elisabeth

2012-12-07

Bat echolocation is primarily used for orientation and foraging but also holds great potential for social communication. The communicative function of echolocation calls is still largely unstudied, especially in the wild. Eavesdropping on vocal signatures encoding social information in echolocation calls has not, to our knowledge, been studied in free-living bats so far. We analysed echolocation calls of the polygynous bat Saccopteryx bilineata and found pronounced vocal signatures encoding sex and individual identity. We showed experimentally that free-living males discriminate approaching male and female conspecifics solely based on their echolocation calls. Males always produced aggressive vocalizations when hearing male echolocation calls and courtship vocalizations when hearing female echolocation calls; hence, they responded with complex social vocalizations in the appropriate social context. Our study demonstrates that social information encoded in bat echolocation calls plays a crucial and hitherto underestimated role for eavesdropping conspecifics and thus facilitates social communication in a highly mobile nocturnal mammal.

Conduits to care: call lights and patients’ perceptions of communication

PubMed Central

Montie, Mary; Shuman, Clayton; Galinato, Jose; Patak, Lance; Anderson, Christine A; Titler, Marita G

2017-01-01

Background Call light systems remain the primary means of hospitalized patients to initiate communication with their health care providers. Although there is vast amounts of literature discussing patient communication with their health care providers, few studies have explored patients’ perceptions concerning call light use and communication. The specific aim of this study was to solicit patients’ perceptions regarding their call light use and communication with nursing staff. Methods Patients invited to this study met the following inclusion criteria: proficient in English, been hospitalized for at least 24 hours, aged ≥21 years, and able to communicate verbally (eg, not intubated). Thirty participants provided written informed consent, were enrolled in the study, and completed interviews. Results Using qualitative descriptive methods, five major themes emerged from patients’ perceptions (namely; establishing connectivity, participant safety concerns, no separation: health care and the call light device, issues with the current call light, and participants’ perceptions of “nurse work”). Multiple minor themes supported these major themes. Data analysis utilized the constant comparative methods of Glaser and Strauss. Discussion Findings from this study extend the knowledge of patients’ understanding of not only why inconsistencies occur between the call light and their nurses, but also why the call light is more than merely a device to initiate communication; rather, it is a direct conduit to their health care and its delivery. PMID:29075125

ICC '86; Proceedings of the International Conference on Communications, Toronto, Canada, June 22-25, 1986, Conference Record. Volumes 1, 2, & 3

NASA Astrophysics Data System (ADS)

Papers are presented on ISDN, mobile radio systems and techniques for digital connectivity, centralized and distributed algorithms in computer networks, communications networks, quality assurance and impact on cost, adaptive filters in communications, the spread spectrum, signal processing, video communication techniques, and digital satellite services. Topics discussed include performance evaluation issues for integrated protocols, packet network operations, the computer network theory and multiple-access, microwave single sideband systems, switching architectures, fiber optic systems, wireless local communications, modulation, coding, and synchronization, remote switching, software quality, transmission, and expert systems in network operations. Consideration is given to wide area networks, image and speech processing, office communications application protocols, multimedia systems, customer-controlled network operations, digital radio systems, channel modeling and signal processing in digital communications, earth station/on-board modems, computer communications system performance evaluation, source encoding, compression, and quantization, and adaptive communications systems.

Machine-Learning Based Channel Quality and Stability Estimation for Stream-Based Multichannel Wireless Sensor Networks.

PubMed

Rehan, Waqas; Fischer, Stefan; Rehan, Maaz

2016-09-12

Wireless sensor networks (WSNs) have become more and more diversified and are today able to also support high data rate applications, such as multimedia. In this case, per-packet channel handshaking/switching may result in inducing additional overheads, such as energy consumption, delays and, therefore, data loss. One of the solutions is to perform stream-based channel allocation where channel handshaking is performed once before transmitting the whole data stream. Deciding stream-based channel allocation is more critical in case of multichannel WSNs where channels of different quality/stability are available and the wish for high performance requires sensor nodes to switch to the best among the available channels. In this work, we will focus on devising mechanisms that perform channel quality/stability estimation in order to improve the accommodation of stream-based communication in multichannel wireless sensor networks. For performing channel quality assessment, we have formulated a composite metric, which we call channel rank measurement (CRM), that can demarcate channels into good, intermediate and bad quality on the basis of the standard deviation of the received signal strength indicator (RSSI) and the average of the link quality indicator (LQI) of the received packets. CRM is then used to generate a data set for training a supervised machine learning-based algorithm (which we call Normal Equation based Channel quality prediction (NEC) algorithm) in such a way that it may perform instantaneous channel rank estimation of any channel. Subsequently, two robust extensions of the NEC algorithm are proposed (which we call Normal Equation based Weighted Moving Average Channel quality prediction (NEWMAC) algorithm and Normal Equation based Aggregate Maturity Criteria with Beta Tracking based Channel weight prediction (NEAMCBTC) algorithm), that can perform channel quality estimation on the basis of both current and past values of channel rank estimation. In the end, simulations are made using MATLAB, and the results show that the Extended version of NEAMCBTC algorithm (Ext-NEAMCBTC) outperforms the compared techniques in terms of channel quality and stability assessment. It also minimizes channel switching overheads (in terms of switching delays and energy consumption) for accommodating stream-based communication in multichannel WSNs.

Machine-Learning Based Channel Quality and Stability Estimation for Stream-Based Multichannel Wireless Sensor Networks

PubMed Central

Rehan, Waqas; Fischer, Stefan; Rehan, Maaz

2016-01-01

Wireless sensor networks (WSNs) have become more and more diversified and are today able to also support high data rate applications, such as multimedia. In this case, per-packet channel handshaking/switching may result in inducing additional overheads, such as energy consumption, delays and, therefore, data loss. One of the solutions is to perform stream-based channel allocation where channel handshaking is performed once before transmitting the whole data stream. Deciding stream-based channel allocation is more critical in case of multichannel WSNs where channels of different quality/stability are available and the wish for high performance requires sensor nodes to switch to the best among the available channels. In this work, we will focus on devising mechanisms that perform channel quality/stability estimation in order to improve the accommodation of stream-based communication in multichannel wireless sensor networks. For performing channel quality assessment, we have formulated a composite metric, which we call channel rank measurement (CRM), that can demarcate channels into good, intermediate and bad quality on the basis of the standard deviation of the received signal strength indicator (RSSI) and the average of the link quality indicator (LQI) of the received packets. CRM is then used to generate a data set for training a supervised machine learning-based algorithm (which we call Normal Equation based Channel quality prediction (NEC) algorithm) in such a way that it may perform instantaneous channel rank estimation of any channel. Subsequently, two robust extensions of the NEC algorithm are proposed (which we call Normal Equation based Weighted Moving Average Channel quality prediction (NEWMAC) algorithm and Normal Equation based Aggregate Maturity Criteria with Beta Tracking based Channel weight prediction (NEAMCBTC) algorithm), that can perform channel quality estimation on the basis of both current and past values of channel rank estimation. In the end, simulations are made using MATLAB, and the results show that the Extended version of NEAMCBTC algorithm (Ext-NEAMCBTC) outperforms the compared techniques in terms of channel quality and stability assessment. It also minimizes channel switching overheads (in terms of switching delays and energy consumption) for accommodating stream-based communication in multichannel WSNs. PMID:27626429

47 CFR 80.111 - Radiotelephone operating procedures for coast stations.

Code of Federal Regulations, 2010 CFR

2010-10-01

... communications in progress, the call may be repeated after three minutes. (5) A coast station must not attempt to... that the called station does not answer, or that communication between the ship station and the called... stations. 80.111 Section 80.111 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) SAFETY AND...

47 CFR 1.20003 - Policies and procedures for employee supervision and control.

Code of Federal Regulations, 2010 CFR

2010-10-01

... or employee responsible for ensuring that any interception of communications or access to call... to implement the interception of communications or access to call-identifying information; (2) An... description of how long it will maintain its records of each interception of communications or access to call...

Bridging the communication gap: successes and challenges of mobile phone technology in a health and demographic surveillance system in northern Nigeria.

PubMed

Doctor, Henry V; Olatunji, Alabi; Jumare, Abdul'azeez

2012-01-01

Maternal and child health indicators are generally poor in Nigeria with the northern part of the country having the worst indicators than the southern part. Efforts to address maternal and health challenges in Nigeria include, among others, improvement in health and management information systems. We report on the experience of mobile phone technology in supporting the activities of a health and demographic surveillance system in northern Nigeria. Our experience calls for the need for the Nigerian Government, the mobile network companies, and the international community at large to consolidate their efforts in addressing the mobile network coverage and power supply challenges in order to create an enabling environment for socio-economic development particularly in rural and disadvantaged areas. Unless power and mobile network challenges are addressed, health interventions that rely on mobile phone technology will not have a significant impact in improving maternal and child health.

An Intelligent Control for the Distributed Flexible Network Photovoltaic System using Autonomous Control and Agent

NASA Astrophysics Data System (ADS)

Park, Sangsoo; Miura, Yushi; Ise, Toshifumi

This paper proposes an intelligent control for the distributed flexible network photovoltaic system using autonomous control and agent. The distributed flexible network photovoltaic system is composed of a secondary battery bank and a number of subsystems which have a solar array, a dc/dc converter and a load. The control mode of dc/dc converter can be selected based on local information by autonomous control. However, if only autonomous control using local information is applied, there are some problems associated with several cases such as voltage drop on long power lines. To overcome these problems, the authors propose introducing agents to improve control characteristics. The autonomous control with agents is called as intelligent control in this paper. The intelligent control scheme that employs the communication between agents is applied for the model system and proved with simulation using PSCAD/EMTDC.

Ubiquitous healthcare computing with SEnsor Grid Enhancement with Data Management System (SEGEDMA).

PubMed

Preve, Nikolaos

2011-12-01

Wireless Sensor Network (WSN) can be deployed to monitor the health of patients suffering from critical diseases. Also a wireless network consisting of biomedical sensors can be implanted into the patient's body and can monitor the patients' conditions. These sensor devices, apart from having an enormous capability of collecting data from their physical surroundings, are also resource constraint in nature with a limited processing and communication ability. Therefore we have to integrate them with the Grid technology in order to process and store the collected data by the sensor nodes. In this paper, we proposed the SEnsor Grid Enhancement Data Management system, called SEGEDMA ensuring the integration of different network technologies and the continuous data access to system users. The main contribution of this work is to achieve the interoperability of both technologies through a novel network architecture ensuring also the interoperability of Open Geospatial Consortium (OGC) and HL7 standards. According to the results, SEGEDMA can be applied successfully in a decentralized healthcare environment.

Nonparametric Density Estimation Based on Self-Organizing Incremental Neural Network for Large Noisy Data.

PubMed

Nakamura, Yoshihiro; Hasegawa, Osamu

2017-01-01

With the ongoing development and expansion of communication networks and sensors, massive amounts of data are continuously generated in real time from real environments. Beforehand, prediction of a distribution underlying such data is difficult; furthermore, the data include substantial amounts of noise. These factors make it difficult to estimate probability densities. To handle these issues and massive amounts of data, we propose a nonparametric density estimator that rapidly learns data online and has high robustness. Our approach is an extension of both kernel density estimation (KDE) and a self-organizing incremental neural network (SOINN); therefore, we call our approach KDESOINN. An SOINN provides a clustering method that learns about the given data as networks of prototype of data; more specifically, an SOINN can learn the distribution underlying the given data. Using this information, KDESOINN estimates the probability density function. The results of our experiments show that KDESOINN outperforms or achieves performance comparable to the current state-of-the-art approaches in terms of robustness, learning time, and accuracy.

Research of the self-healing technologies in the optical communication network of distribution automation

NASA Astrophysics Data System (ADS)

Wang, Hao; Zhong, Guoxin

2018-03-01

Optical communication network is the mainstream technique of the communication networks for distribution automation, and self-healing technologies can improve the in reliability of the optical communication networks significantly. This paper discussed the technical characteristics and application scenarios of several network self-healing technologies in the access layer, the backbone layer and the core layer of the optical communication networks for distribution automation. On the base of the contrastive analysis, this paper gives an application suggestion of these self-healing technologies.

The CASA Dallas Fort Worth Remote Sensing Network ICT for Urban Disaster Mitigation

NASA Astrophysics Data System (ADS)

Chandrasekar, Venkatachalam; Chen, Haonan; Philips, Brenda; Seo, Dong-jun; Junyent, Francesc; Bajaj, Apoorva; Zink, Mike; Mcenery, John; Sukheswalla, Zubin; Cannon, Amy; Lyons, Eric; Westbrook, David

2013-04-01

The dual-polarization X-band radar network developed by the U.S. National Science Foundation Engineering Center for Collaborative Adaptive Sensing of the Atmosphere (CASA) has shown great advantages for observing and prediction of hazardous weather events in the lower atmosphere (1-3 km above ground level). The network is operating though a scanning methodology called DCAS, distributed collaborative adaptive sensing, which is designed to focus on particular interesting regions of the atmosphere and disseminate information for decision-making to multiple end-users, such as emergency managers and policy analysts. Since spring 2012, CASA and the North Central Texas Council of Governments (NCTCOG) have embarked the development of Dallas Fort Worth (DFW) urban remote sensing network, including 8-node of dual-polarization X-band radars, in the populous DFW Metroplex (pop. 6.3 million in 2010). The main goal of CASA DFW urban demonstration network is to protect the safety and prosperity of humans and ecosystems through research activities that include: 1) to demonstrate the DCAS operation paradigm developed by CASA; 2) to create high-resolution, three-dimensional mapping of the meteorological conditions; 3) to help the local emergency managers issue impacts-based warnings and forecasts for severe wind, tornado, hail, and flash flood hazards. The products of this radar network will include single and multi-radar data, vector wind retrieval, quantitative precipitation estimation and nowcasting, and numerical weather predictions. In addition, the high spatial and temporal resolution rainfall products from CASA can serve as a reliable data input for distributed hydrological models in urban area. This paper presents the information and communication link between radars, rainfall product generation, hydrologic model link and end user community in the Dallas Fort Worth Urban Network. Specific details of the Information and Communication Technologies (ICT) between the various subsystems are presented.

Considerations and Architectures for Inter-Satellite Communications in Distributed Spacecraft Systems

NASA Technical Reports Server (NTRS)

Edwards, Bernard; Horne, William; Israel, David; Kwadrat, Carl; Bauer, Frank H. (Technical Monitor)

2001-01-01

This paper will identify the important characteristics and requirements necessary for inter-satellite communications in distributed spacecraft systems and present analysis results focusing on architectural and protocol comparisons. Emerging spacecraft systems plan to deploy multiple satellites in various "distributed" configurations ranging from close proximity formation flying to widely separated constellations. Distributed spacecraft configurations provide advantages for science exploration and operations since many activities useful for missions may be better served by distributing them between spacecraft. For example, many scientific observations can be enhanced through spatially separated platforms, such as for deep space interferometry. operating multiple distributed spacecraft as a mission requires coordination that may be best provided through inter-satellite communications. For example, several future distributed spacecraft systems envision autonomous operations requiring relative navigational calculations and coordinated attitude and position corrections. To conduct these operations, data must be exchanged between spacecraft. Direct cross-links between satellites provides an efficient and practical method for transferring data and commands. Unlike existing "bent-pipe" relay networks supporting space missions, no standard or widely-used method exists for cross-link communications. Consequently, to support these future missions, the characteristics necessary for inter-satellite communications need to be examined. At first glance, all of the missions look extremely different. Some missions call for tens to hundreds of nano-satellites in constant communications in close proximity to each other. Other missions call for a handful of satellites communicating very slowly over thousands to hundreds of thousands of kilometers. The paper will first classify distributed spacecraft missions to help guide the evaluation and definition of cross-link architectures and approaches. Based on this general classification, the paper will examine general physical layer parameters, such as frequency bands and data rates, necessary to support the missions. The paper will also identify classes of communication architectures that may be employed, ranging from fully distributed to centralized topologies. Numerous factors, such as number of spacecraft, must be evaluated when attempting to pick a communications architecture. Also important is the stability of the formation from a communications standpoint. For example, do all of the spacecraft require equal bandwidth and are spacecraft allowed to enter and leave a formation? The type of science mission being attempted may also heavily influence the communications architecture. In addition, the paper will assess various parameters and characteristics typically associated with the data link layer. The paper will analyze the performance of various multiple access techniques given the operational scenario, requirements, and communication topologies envisioned for missions. This assessment will also include a survey of existing standards and their applicability for distributed spacecraft systems. An important consideration includes the interoperability of the lower layers (physical and data link) examined in this paper with the higher layer protocols(network) envisioned for future space internetworking. Finally, the paper will define a suggested path, including preliminary recommendations, for defining and developing a standard for intersatellite communications based on the classes of distributed spacecraft missions and analysis results.

Toward the virtual classroom

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

Pihlman, M.; Dirks, D.H.

1990-01-03

The Lawrence Livermore National Laboratory (LLNL) encourages its employees to remotely attend classes given by Stanford University, University of California at Davis, and the National Technological University (NTU). To improve the quality of education for LLNL employees, we are cooperating with Stanford University in upgrading the Stanford Instructional Television Network (SITN). A dedicated high-speed communication link (Tl) between Stanford and LLNL will be used for enhanced services such as videoconferencing, real time classnotes distribution, and electronic distribution of homework assignments. The new network will also allow students to take classes from their offices with the ability to ask the professormore » questions via an automatically dialed telephone call. As part of this upgrade, we have also proposed a new videoconferencing based classroom environment where students taking remote classes would feel as though they are attending the live class. All paperwork would be available in near real time and students may converse normally with, and see, other remote students as though they were all in the same physical location. We call this the Virtual Classroom.'' 1 ref., 6 figs.« less

StegoWall: blind statistical detection of hidden data

NASA Astrophysics Data System (ADS)

Voloshynovskiy, Sviatoslav V.; Herrigel, Alexander; Rytsar, Yuri B.; Pun, Thierry

2002-04-01

Novel functional possibilities, provided by recent data hiding technologies, carry out the danger of uncontrolled (unauthorized) and unlimited information exchange that might be used by people with unfriendly interests. The multimedia industry as well as the research community recognize the urgent necessity for network security and copyright protection, or rather the lack of adequate law for digital multimedia protection. This paper advocates the need for detecting hidden data in digital and analog media as well as in electronic transmissions, and for attempting to identify the underlying hidden data. Solving this problem calls for the development of an architecture for blind stochastic hidden data detection in order to prevent unauthorized data exchange. The proposed architecture is called StegoWall; its key aspects are the solid investigation, the deep understanding, and the prediction of possible tendencies in the development of advanced data hiding technologies. The basic idea of our complex approach is to exploit all information about hidden data statistics to perform its detection based on a stochastic framework. The StegoWall system will be used for four main applications: robust watermarking, secret communications, integrity control and tamper proofing, and internet/network security.

vMon-mobile provides wireless connection to the electronic patient record

NASA Astrophysics Data System (ADS)

Oliveira, Pedro P., Jr.; Rebelo, Marina; Pilon, Paulo E.; Gutierrez, Marco A.; Tachinardi, Umberto

2002-05-01

This work presents the development of a set of tools to help doctors to continuously monitor critical patients. Real-time monitoring signals are displayed via a Web Based Electronic Patient Record (Web-EPR) developed at the Heart Institute. Any computer on the Hospital's Intranet can access the Web-EPR that will open a browser plug-in called vMon. Recently vMon was adapted to wireless mobile devices providing the same real-time visualization of vital signals of its desktop counterpart. The monitoring network communicates with the hospital network through a gateway using HL7 messages and has the ability to export waveforms in real time using the multicast protocol through an API library. A dedicated ActiveX component was built that establishes the streaming of the biomedical signals under monitoring and displays them on an Internet Explorer 5.x browser. The mobile version - called vMon-mobile - will parse the browser window and deliver it to a PDA device connected to a local area network. The result is a virtual monitor presenting real-time data on a mobile device. All parameters and signals acquired from the moment the patient is connected to the monitors are stored for a few days. The most clinically relevant information is added to patient's EPR.

Performance verification of network function virtualization in software defined optical transport networks

NASA Astrophysics Data System (ADS)

Zhao, Yongli; Hu, Liyazhou; Wang, Wei; Li, Yajie; Zhang, Jie

2017-01-01

With the continuous opening of resource acquisition and application, there are a large variety of network hardware appliances deployed as the communication infrastructure. To lunch a new network application always implies to replace the obsolete devices and needs the related space and power to accommodate it, which will increase the energy and capital investment. Network function virtualization1 (NFV) aims to address these problems by consolidating many network equipment onto industry standard elements such as servers, switches and storage. Many types of IT resources have been deployed to run Virtual Network Functions (vNFs), such as virtual switches and routers. Then how to deploy NFV in optical transport networks is a of great importance problem. This paper focuses on this problem, and gives an implementation architecture of NFV-enabled optical transport networks based on Software Defined Optical Networking (SDON) with the procedure of vNFs call and return. Especially, an implementation solution of NFV-enabled optical transport node is designed, and a parallel processing method for NFV-enabled OTN nodes is proposed. To verify the performance of NFV-enabled SDON, the protocol interaction procedures of control function virtualization and node function virtualization are demonstrated on SDON testbed. Finally, the benefits and challenges of the parallel processing method for NFV-enabled OTN nodes are simulated and analyzed.

A Real-time Spectrum Handoff Algorithm for VoIP based Cognitive Radio Networks: Design and Performance Analysis

NASA Astrophysics Data System (ADS)

Chakraborty, Tamal; Saha Misra, Iti

2016-03-01

Secondary Users (SUs) in a Cognitive Radio Network (CRN) face unpredictable interruptions in transmission due to the random arrival of Primary Users (PUs), leading to spectrum handoff or dropping instances. An efficient spectrum handoff algorithm, thus, becomes one of the indispensable components in CRN, especially for real-time communication like Voice over IP (VoIP). In this regard, this paper investigates the effects of spectrum handoff on the Quality of Service (QoS) for VoIP traffic in CRN, and proposes a real-time spectrum handoff algorithm in two phases. The first phase (VAST-VoIP based Adaptive Sensing and Transmission) adaptively varies the channel sensing and transmission durations to perform intelligent dropping decisions. The second phase (ProReact-Proactive and Reactive Handoff) deploys efficient channel selection mechanisms during spectrum handoff for resuming communication. Extensive performance analysis in analytical and simulation models confirms a decrease in spectrum handoff delay for VoIP SUs by more than 40% and 60%, compared to existing proactive and reactive algorithms, respectively and ensures a minimum 10% reduction in call-dropping probability with respect to the previous works in this domain. The effective SU transmission duration is also maximized under the proposed algorithm, thereby making it suitable for successful VoIP communication.

MED34/448: The Networked Health-Care Environment of the Future: Requirements for new human abilities

PubMed Central

Patel, V; Shortliffe, E; Kaufman, D

1999-01-01

The implications of the Internet for health care are increasingly understood as scientists, health workers, patients, and health administrators envision new applications, new means for communicating about health issues, and new ways of accessing pertinent health information at the point of care. It is important to study not only the new technologies themselves, but also to recognize that the optimal use of these technologies requires new skills by users. Not only must both patients and health professionals be taught the basic skills related to use of networking technologies, but those who develop future systems must understand the new human abilities that are implied by the remarkable changes that are envisioned. We describe the results of research that have implications for effectively exploiting networking technology in order to enhance creativity, collaboration, and communication. The development and implementation of enabling tools and methods that provide ready access to knowledge and information are among the central goals of medical informatics. Given the immensity of this challenge, the need for multi-institutional collaboration is increasingly being recognized. Collaboration has typically involved individuals who work together at the same location. With the evolution of electronic communication modalities, workers at Harvard, Columbia, McGill, and Stanford Universities jointly investigated the role that networking technologies can play in supporting research collaboration at a distance. All communications among the workers from the other three institutions were observed in order to gain insights into the limitations and successes of communications technology in supporting this distributed creative process. We analyzed the activities of the Intermed team as they sought to develop a common representation for clinical guidelines, known as the GuideLine Interchange Format (GLIF). These activities can be described as a process of computer-mediated collaborative design. We report here on the cognitive, socio-cultural, and logistical issues encountered when scientists from diverse organizations and backgrounds use communications technologies while designing and implementing shared products. Results demonstrate that the effectiveness of communication modalities is predicated on the specific objectives of the task. We identify suitable uses of email, conference calls, and face-to-face meetings. The leaders play an integral role in guiding and facilitating the group activities across modalities. Most important was the proper use of technology to support the evolution of a shared vision of group goals and methods, an element that is clearly necessary before successful collaborative designs can proceed. We interpret these research findings as they relate to the scientific collaboration via the Internet with specific focus on changes in skills required with these new media of communication.

Unobstructive Body Area Networks (BAN) for efficient movement monitoring.

PubMed

Felisberto, Filipe; Costa, Nuno; Fdez-Riverola, Florentino; Pereira, António

2012-01-01

The technological advances in medical sensors, low-power microelectronics and miniaturization, wireless communications and networks have enabled the appearance of a new generation of wireless sensor networks: the so-called wireless body area networks (WBAN). These networks can be used for continuous monitoring of vital parameters, movement, and the surrounding environment. The data gathered by these networks contributes to improve users' quality of life and allows the creation of a knowledge database by using learning techniques, useful to infer abnormal behaviour. In this paper we present a wireless body area network architecture to recognize human movement, identify human postures and detect harmful activities in order to prevent risk situations. The WBAN was created using tiny, cheap and low-power nodes with inertial and physiological sensors, strategically placed on the human body. Doing so, in an as ubiquitous as possible way, ensures that its impact on the users' daily actions is minimum. The information collected by these sensors is transmitted to a central server capable of analysing and processing their data. The proposed system creates movement profiles based on the data sent by the WBAN's nodes, and is able to detect in real time any abnormal movement and allows for a monitored rehabilitation of the user.

Educational network comparative analysis of small groups: Short- and long-term communications

NASA Astrophysics Data System (ADS)

Berg, D. B.; Zvereva, O. M.; Nazarova, Yu. Yu.; Chepurov, E. G.; Kokovin, A. V.; Ranyuk, S. V.

2017-11-01

The present study is devoted to the discussion of small group communication network structures. These communications were observed in student groups, where actors were united with a regular educational activity. The comparative analysis was carried out for networks of short-term (1 hour) and long-term (4 weeks) communications, it was based on seven structural parameters, and consisted of two stages. At the first stage, differences between the network graphs were examined, and the random corresponding Bernoulli graphs were built. At the second stage, revealed differences were compared. Calculations were performed using UCINET software framework. It was found out that networks of long-term and short-term communications are quite different: the structure of a short-term communication network is close to a random one, whereas the most of long-term communication network parameters differ from the corresponding random ones by more than 30%. This difference can be explained by strong "noisiness" of a short-term communication network, and the lack of social in it.

Intelligent buildings.

PubMed

Williams, W E

1987-01-01

The maturing of technologies in computer capabilities, particularly direct digital signals, has provided an exciting variety of new communication and facility control opportunities. These include telecommunications, energy management systems, security systems, office automation systems, local area networks, and video conferencing. New applications are developing continuously. The so-called "intelligent" or "smart" building concept evolves from the development of this advanced technology in building environments. Automation has had a dramatic effect on facility planning. For decades, communications were limited to the telephone, the typewritten message, and copy machines. The office itself and its functions had been essentially unchanged for decades. Office automation systems began to surface during the energy crisis and, although their newer technology was timely, they were, for the most part, designed separately from other new building systems. For example, most mainframe computer systems were originally stand-alone, as were word processing installations. In the last five years, the advances in distributive systems, networking, and personal computer capabilities have provided opportunities to make such dramatic improvements in productivity that the Selectric typewriter has gone from being the most advanced piece of office equipment to nearly total obsolescence.

Structure of Radical-Induced Cell Death1 Hub Domain Reveals a Common αα-Scaffold for Disorder in Transcriptional Networks.

PubMed

Bugge, Katrine; Staby, Lasse; Kemplen, Katherine R; O'Shea, Charlotte; Bendsen, Sidsel K; Jensen, Mikael K; Olsen, Johan G; Skriver, Karen; Kragelund, Birthe B

2018-05-01

Communication within cells relies on a few protein nodes called hubs, which organize vast interactomes with many partners. Frequently, hub proteins are intrinsically disordered conferring multi-specificity and dynamic communication. Conversely, folded hub proteins may organize networks using disordered partners. In this work, the structure of the RST domain, a unique folded hub, is solved by nuclear magnetic resonance spectroscopy and small-angle X-ray scattering, and its complex with a region of the transcription factor DREB2A is provided through data-driven HADDOCK modeling and mutagenesis analysis. The RST fold is unique, but similar structures are identified in the PAH (paired amphipathic helix), TAFH (TATA-box-associated factor homology), and NCBD (nuclear coactivator binding domain) domains. We designate them as a group the αα hubs, as they share an αα-hairpin super-secondary motif, which serves as an organizing platform for malleable helices of varying topology. This allows for partner adaptation, exclusion, and selection. Our findings provide valuable insights into structural features enabling signaling fidelity. Copyright © 2018 Elsevier Ltd. All rights reserved.

Staggered scheduling of sensor estimation and fusion for tracking over long-haul links

DOE PAGES

Liu, Qiang; Rao, Nageswara S. V.; Wang, Xin

2016-08-01

Networked sensing can be found in a multitude of real-world applications. Here, we focus on the communication-and computation-constrained long-haul sensor networks, where sensors are remotely deployed over a vast geographical area to perform certain tasks. Of special interest is a class of such networks where sensors take measurements of one or more dynamic targets and send their state estimates to a remote fusion center via long-haul satellite links. The severe loss and delay over such links can easily reduce the amount of sensor data received by the fusion center, thereby limiting the potential information fusion gain and resulting in suboptimalmore » tracking performance. In this paper, starting with the temporal-domain staggered estimation for an individual sensor, we explore the impact of the so-called intra-state prediction and retrodiction on estimation errors. We then investigate the effect of such estimation scheduling across different sensors on the spatial-domain fusion performance, where the sensing time epochs across sensors are scheduled in an asynchronous and staggered manner. In particular, the impact of communication delay and loss as well as sensor bias on such scheduling is explored by means of numerical and simulation studies that demonstrate the validity of our analysis.« less

Improving the scalability of hyperspectral imaging applications on heterogeneous platforms using adaptive run-time data compression

NASA Astrophysics Data System (ADS)

Plaza, Antonio; Plaza, Javier; Paz, Abel

2010-10-01

Latest generation remote sensing instruments (called hyperspectral imagers) are now able to generate hundreds of images, corresponding to different wavelength channels, for the same area on the surface of the Earth. In previous work, we have reported that the scalability of parallel processing algorithms dealing with these high-dimensional data volumes is affected by the amount of data to be exchanged through the communication network of the system. However, large messages are common in hyperspectral imaging applications since processing algorithms are pixel-based, and each pixel vector to be exchanged through the communication network is made up of hundreds of spectral values. Thus, decreasing the amount of data to be exchanged could improve the scalability and parallel performance. In this paper, we propose a new framework based on intelligent utilization of wavelet-based data compression techniques for improving the scalability of a standard hyperspectral image processing chain on heterogeneous networks of workstations. This type of parallel platform is quickly becoming a standard in hyperspectral image processing due to the distributed nature of collected hyperspectral data as well as its flexibility and low cost. Our experimental results indicate that adaptive lossy compression can lead to improvements in the scalability of the hyperspectral processing chain without sacrificing analysis accuracy, even at sub-pixel precision levels.

A Proposal of TLS Implementation for Cross Certification Model

NASA Astrophysics Data System (ADS)

Kaji, Tadashi; Fujishiro, Takahiro; Tezuka, Satoru

Today, TLS is widely used for achieving a secure communication system. And TLS is used PKI for server authentication and/or client authentication. However, its PKI environment, which is called as “multiple trust anchors environment,” causes the problem that the verifier has to maintain huge number of CA certificates in the ubiquitous network because the increase of terminals connected to the network brings the increase of CAs. However, most of terminals in the ubiquitous network will not have enough memory to hold such huge number of CA certificates. Therefore, another PKI environment, “cross certification environment”, is useful for the ubiquitous network. But, because current TLS is designed for the multiple trust anchors model, TLS cannot work efficiently on the cross-certification model. This paper proposes a TLS implementation method to support the cross certification model efficiently. Our proposal reduces the size of exchanged messages between the TLS client and the TLS server during the handshake process. Therefore, our proposal is suitable for implementing TLS in the terminals that do not have enough computing power and memory in ubiquitous network.

Remote preparation of an atomic quantum memory.

PubMed

Rosenfeld, Wenjamin; Berner, Stefan; Volz, Jürgen; Weber, Markus; Weinfurter, Harald

2007-02-02

Storage and distribution of quantum information are key elements of quantum information processing and future quantum communication networks. Here, using atom-photon entanglement as the main physical resource, we experimentally demonstrate the preparation of a distant atomic quantum memory. Applying a quantum teleportation protocol on a locally prepared state of a photonic qubit, we realized this so-called remote state preparation on a single, optically trapped 87Rb atom. We evaluated the performance of this scheme by the full tomography of the prepared atomic state, reaching an average fidelity of 82%.

Time-Reversal Based Range Extension Technique for Ultra-wideband (UWB) Sensors and Applications in Tactical Communications and Networking

DTIC Science & Technology

2007-10-16

ABSTRACT c. THIS PAGE ABSTRACT OF Francis Otuonye P U UU24 19b. TELEPHONE NUMBER (Include area code ) 24 931-372-3374 Standard Form 298 (Rev. 8/98...modulation pulse wavefom--sotware defined or cognitive. From a information-theoretical viewpoint, the two parts as a whole form so-called "pre- coding ". I...The time domain system Fig. 2.3(b) is based on digital sampling oscilloscope (DSO), Textronix TDS 7000E3. The time domain sounder has the capability

76 FR 23812 - Reliability and Continuity of Communications Networks, Including Broadband Technologies; Effects...

Federal Register 2010, 2011, 2012, 2013, 2014

2011-04-28

... FEDERAL COMMUNICATIONS COMMISSION [PS Docket Nos. 11-60 and 10-92; ET Docket No. 06-119] Reliability and Continuity of Communications Networks, Including Broadband Technologies; Effects on Broadband Communications Networks of Damage or Failure of Network Equipment or Severe Overload; Independent Panel Reviewing...

Alternative Path Communication in Wide-Scale Cluster-Tree Wireless Sensor Networks Using Inactive Periods

PubMed Central

Leão, Erico; Montez, Carlos; Moraes, Ricardo; Portugal, Paulo; Vasques, Francisco

2017-01-01

The IEEE 802.15.4/ZigBee cluster-tree topology is a suitable technology to deploy wide-scale Wireless Sensor Networks (WSNs). These networks are usually designed to support convergecast traffic, where all communication paths go through the PAN (Personal Area Network) coordinator. Nevertheless, peer-to-peer communication relationships may be also required for different types of WSN applications. That is the typical case of sensor and actuator networks, where local control loops must be closed using a reduced number of communication hops. The use of communication schemes optimised just for the support of convergecast traffic may result in higher network congestion and in a potentially higher number of communication hops. Within this context, this paper proposes an Alternative-Route Definition (ARounD) communication scheme for WSNs. The underlying idea of ARounD is to setup alternative communication paths between specific source and destination nodes, avoiding congested cluster-tree paths. These alternative paths consider shorter inter-cluster paths, using a set of intermediate nodes to relay messages during their inactive periods in the cluster-tree network. Simulation results show that the ARounD communication scheme can significantly decrease the end-to-end communication delay, when compared to the use of standard cluster-tree communication schemes. Moreover, the ARounD communication scheme is able to reduce the network congestion around the PAN coordinator, enabling the reduction of the number of message drops due to queue overflows in the cluster-tree network. PMID:28481245

Alternative Path Communication in Wide-Scale Cluster-Tree Wireless Sensor Networks Using Inactive Periods.

PubMed

Leão, Erico; Montez, Carlos; Moraes, Ricardo; Portugal, Paulo; Vasques, Francisco

2017-05-06

The IEEE 802.15.4/ZigBee cluster-tree topology is a suitable technology to deploy wide-scale Wireless Sensor Networks (WSNs). These networks are usually designed to support convergecast traffic, where all communication paths go through the PAN (Personal Area Network) coordinator. Nevertheless, peer-to-peer communication relationships may be also required for different types of WSN applications. That is the typical case of sensor and actuator networks, where local control loops must be closed using a reduced number of communication hops. The use of communication schemes optimised just for the support of convergecast traffic may result in higher network congestion and in a potentially higher number of communication hops. Within this context, this paper proposes an Alternative-Route Definition (ARounD) communication scheme for WSNs. The underlying idea of ARounD is to setup alternative communication paths between specific source and destination nodes, avoiding congested cluster-tree paths. These alternative paths consider shorter inter-cluster paths, using a set of intermediate nodes to relay messages during their inactive periods in the cluster-tree network. Simulation results show that the ARounD communication scheme can significantly decrease the end-to-end communication delay, when compared to the use of standard cluster-tree communication schemes. Moreover, the ARounD communication scheme is able to reduce the network congestion around the PAN coordinator, enabling the reduction of the number of message drops due to queue overflows in the cluster-tree network.

Metamodeling and the Critic-based approach to multi-level optimization.

PubMed

Werbos, Ludmilla; Kozma, Robert; Silva-Lugo, Rodrigo; Pazienza, Giovanni E; Werbos, Paul J

2012-08-01

Large-scale networks with hundreds of thousands of variables and constraints are becoming more and more common in logistics, communications, and distribution domains. Traditionally, the utility functions defined on such networks are optimized using some variation of Linear Programming, such as Mixed Integer Programming (MIP). Despite enormous progress both in hardware (multiprocessor systems and specialized processors) and software (Gurobi) we are reaching the limits of what these tools can handle in real time. Modern logistic problems, for example, call for expanding the problem both vertically (from one day up to several days) and horizontally (combining separate solution stages into an integrated model). The complexity of such integrated models calls for alternative methods of solution, such as Approximate Dynamic Programming (ADP), which provide a further increase in the performance necessary for the daily operation. In this paper, we present the theoretical basis and related experiments for solving the multistage decision problems based on the results obtained for shorter periods, as building blocks for the models and the solution, via Critic-Model-Action cycles, where various types of neural networks are combined with traditional MIP models in a unified optimization system. In this system architecture, fast and simple feed-forward networks are trained to reasonably initialize more complicated recurrent networks, which serve as approximators of the value function (Critic). The combination of interrelated neural networks and optimization modules allows for multiple queries for the same system, providing flexibility and optimizing performance for large-scale real-life problems. A MATLAB implementation of our solution procedure for a realistic set of data and constraints shows promising results, compared to the iterative MIP approach. Copyright © 2012 Elsevier Ltd. All rights reserved.

Development of wireless sensor network for landslide monitoring system

NASA Astrophysics Data System (ADS)

Suryadi; Puranto, Prabowo; Adinanta, Hendra; Tohari, Adrin; Priambodo, Purnomo S.

2017-05-01

A wireless sensor network has been developed to monitor soil movement of some observed areas periodically. The system consists of four nodes and one gateway which installed on a scope area of 0.2 Km2. Each of nodehastwo types of sensor,an inclinometer and an extensometer. An inclinometer sensor is used to measure the tilt of a structure while anextensometer sensor is used to measure the displacement of soil movement. Each of nodeisalso supported by awireless communication device, a solar power supply unit, and a microcontroller unit called sensor module. In this system, there is also gateway module as a main communication system consistinga wireless communication device, power supply unit, and rain gauge to measure the rainfall intensity of the observed area. Each sensor of inclinometer and extensometer isconnected to the sensor module in wiring system but sensor module iscommunicating with gateway in a wireless system. Those four nodes are alsoconnectedeach other in a wireless system collecting the data from inclinometer and extensometer sensors. Module Gateway istransmitting the instruction code to each sensor module one by one and collecting the data from them. Gateway module is an important part to communicate with not only sensor modules but also to the server. This wireless system wasdesigned toreducethe electric consumption powered by 80 WP solar panel and 55Ah battery. This system has been implemented in Pangalengan, Bandung, which has high intensity of rainfall and it can be seen on the website.

DICOM: a standard for medical imaging

NASA Astrophysics Data System (ADS)

Horii, Steven C.; Bidgood, W. Dean

1993-01-01

Since 1983, the American College of Radiology (ACR) and the National Electrical Manufacturers Association (NEMA) have been engaged in developing standards related to medical imaging. This alliance of users and manufacturers was formed to meet the needs of the medical imaging community as its use of digital imaging technology increased. The development of electronic picture archiving and communications systems (PACS), which could connect a number of medical imaging devices together in a network, led to the need for a standard interface and data structure for use on imaging equipment. Since medical image files tend to be very large and include much text information along with the image, the need for a fast, flexible, and extensible standard was quickly established. The ACR-NEMA Digital Imaging and Communications Standards Committee developed a standard which met these needs. The standard (ACR-NEMA 300-1988) was first published in 1985 and revised in 1988. It is increasingly available from equipment manufacturers. The current work of the ACR- NEMA Committee has been to extend the standard to incorporate direct network connection features, and build on standards work done by the International Standards Organization in its Open Systems Interconnection series. This new standard, called Digital Imaging and Communication in Medicine (DICOM), follows an object-oriented design methodology and makes use of as many existing internationally accepted standards as possible. This paper gives a brief overview of the requirements for communications standards in medical imaging, a history of the ACR-NEMA effort and what it has produced, and a description of the DICOM standard.

Comparison of neural network applications for channel assignment in cellular TDMA networks and dynamically sectored PCS networks

NASA Astrophysics Data System (ADS)

Hortos, William S.

1997-04-01

The use of artificial neural networks (NNs) to address the channel assignment problem (CAP) for cellular time-division multiple access and code-division multiple access networks has previously been investigated by this author and many others. The investigations to date have been based on a hexagonal cell structure established by omnidirectional antennas at the base stations. No account was taken of the use of spatial isolation enabled by directional antennas to reduce interference between mobiles. Any reduction in interference translates into increased capacity and consequently alters the performance of the NNs. Previous studies have sought to improve the performance of Hopfield- Tank network algorithms and self-organizing feature map algorithms applied primarily to static channel assignment (SCA) for cellular networks that handle uniformly distributed, stationary traffic in each cell for a single type of service. The resulting algorithms minimize energy functions representing interference constraint and ad hoc conditions that promote convergence to optimal solutions. While the structures of the derived neural network algorithms (NNAs) offer the potential advantages of inherent parallelism and adaptability to changing system conditions, this potential has yet to be fulfilled the CAP for emerging mobile networks. The next-generation communication infrastructures must accommodate dynamic operating conditions. Macrocell topologies are being refined to microcells and picocells that can be dynamically sectored by adaptively controlled, directional antennas and programmable transceivers. These networks must support the time-varying demands for personal communication services (PCS) that simultaneously carry voice, data and video and, thus, require new dynamic channel assignment (DCA) algorithms. This paper examines the impact of dynamic cell sectoring and geometric conditioning on NNAs developed for SCA in omnicell networks with stationary traffic to improve the metrics of convergence rate and call blocking. Genetic algorithms (GAs) are also considered in PCS networks as a means to overcome the known weakness of Hopfield NNAs in determining global minima. The resulting GAs for DCA in PCS networks are compared to improved DCA algorithms based on Hopfield NNs for stationary cellular networks. Algorithm performance is compared on the basis of rate of convergence, blocking probability, analytic complexity, and parametric sensitivity to transient traffic demands and channel interference.

Ubiquitous health monitoring system for multiple users using a ZigBee and WLAN dual-network.

PubMed

Cha, Yong Dae; Yoon, Gilwon

2009-11-01

A ubiquitous health monitoring system for multiple users was developed based on a ZigBee and wireless local area network (WLAN) dual-network. A compact biosignal monitoring unit (BMU) for measuring electrocardiogram (ECG), photoplethysmogram (PPG), and temperature was also developed. A single 8-bit microcontroller operated the BMU including most of digital filtering and wireless communication. The BMU with its case was reduced to 55 x 35 x 15 mm and 33 g. In routine use, vital signs of 6 bytes/sec (heart rate, temperature, pulse transit time) per each user were transmitted through a ZigBee module even though all the real-time data were recorded in a secure digital memory of the BMU. In an emergency or when need arises, a channel of a particular user was switched to another ZigBee module, called the emergency module, that sent all ECG and PPG waveforms in real time. Each emergency ZigBee module handled up to a few users. Data from multiple users were wirelessly received by the ZigBee receiver modules in a controller called ZigBee-WLAN gateway, where the ZigBee modules were connected to a WLAN module. This WLAN module sent all data wirelessly to a monitoring center. Operating the dual modes of ZigBee/WLAN utilized an advantage of ZigBee by handling multiple users with minimum power consumption, and overcame the ZigBee limitation of low data rate. This dual-network system for LAN is economically competitive and reliable.

Apparatus and method for data communication in an energy distribution network

DOEpatents

Hussain, Mohsin; LaPorte, Brock; Uebel, Udo; Zia, Aftab

2014-07-08

A system for communicating information on an energy distribution network is disclosed. In one embodiment, the system includes a local supervisor on a communication network, wherein the local supervisor can collect data from one or more energy generation/monitoring devices. The system also includes a command center on the communication network, wherein the command center can generate one or more commands for controlling the one or more energy generation devices. The local supervisor can periodically transmit a data signal indicative of the data to the command center via a first channel of the communication network at a first interval. The local supervisor can also periodically transmit a request for a command to the command center via a second channel of the communication network at a second interval shorter than the first interval. This channel configuration provides effective data communication without a significant increase in the use of network resources.

Multi-board kernel communication using socket programming for embedded applications

NASA Astrophysics Data System (ADS)

Mishra, Ashish; Girdhar, Neha; Krishnia, Nikita

2016-03-01

It is often seen in large application projects, there is a need to communicate between two different processors or two different kernels. The aim of this paper is to communicate between two different kernels and use efficient method to do so. The TCP/IP protocol is implemented to communicate between two boards via the Ethernet port and use lwIP (lightweight IP) stack, which is a smaller independent implementation of the TCP/IP stack suitable for use in embedded systems. While retaining TCP/IP functionality, lwIP stack reduces the use of memory and even size of the code. In this process of communication we made Raspberry pi as an active client and Field programmable gate array(FPGA) board as a passive server and they are allowed to communicate via Ethernet. Three applications based on TCP/IP client-server network communication have been implemented. The Echo server application is used to communicate between two different kernels of two different boards. Socket programming is used as it is independent of platform and programming language used. TCP transmit and receive throughput test applications are used to measure maximum throughput of the transmission of data. These applications are based on communication to an open source tool called iperf. It is used to measure the throughput transmission rate by sending or receiving some constant piece of data to the client or server according to the test application.

HIV communication capacity strengthening: a critical review.

PubMed

Lettenmaier, Cheryl; Kraft, Joan Marie; Raisanen, Keris; Serlemitsos, Elizabeth

2014-08-15

HIV communication is most effective and sustainable when it is designed and implemented locally and tailored to the local context. This requires capacity strengthening at national, subnational, and community levels. Through a review of the published and selected "grey" literature, we examine HIV communication capacity strengthening: definitions, measurements, implementation, and effects. We found limited documentation of HIV communication capacity needs or systematic approaches to address them. Most HIV communication capacity strengthening to date has focused on building individual competencies to design and manage social and behavior change communication programs through training courses, often coupled with networking opportunities for participants, post-training mentoring, and technical assistance. A few of these efforts have been evaluated through pre- and post-training tests and qualitative interviews with participants and have shown potential for improvement in individual skills and knowledge. Health communication capacity assessment tools that measure individual and organizational competencies exist, but they have most often been used to identify capacity building needs, not for evaluating capacity strengthening efforts. A new definition of capacity strengthening, grown out of recent efforts to improve effectiveness of international health and development programs, focuses on improving organizational and societal systems that support performance and individual competencies. We propose a holistic model for HIV communication capacity strengthening and call for rigorous documentation and evaluation to determine and scale-up optimal capacity building interventions for strengthening social and behavior change communication for HIV prevention, care, and treatment in developing countries.

Computer hardware fault administration

DOEpatents

Archer, Charles J.; Megerian, Mark G.; Ratterman, Joseph D.; Smith, Brian E.

2010-09-14

Computer hardware fault administration carried out in a parallel computer, where the parallel computer includes a plurality of compute nodes. The compute nodes are coupled for data communications by at least two independent data communications networks, where each data communications network includes data communications links connected to the compute nodes. Typical embodiments carry out hardware fault administration by identifying a location of a defective link in the first data communications network of the parallel computer and routing communications data around the defective link through the second data communications network of the parallel computer.

Open source system OpenVPN in a function of Virtual Private Network

NASA Astrophysics Data System (ADS)

Skendzic, A.; Kovacic, B.

2017-05-01

Using of Virtual Private Networks (VPN) can establish high security level in network communication. VPN technology enables high security networking using distributed or public network infrastructure. VPN uses different security and managing rules inside networks. It can be set up using different communication channels like Internet or separate ISP communication infrastructure. VPN private network makes security communication channel over public network between two endpoints (computers). OpenVPN is an open source software product under GNU General Public License (GPL) that can be used to establish VPN communication between two computers inside business local network over public communication infrastructure. It uses special security protocols and 256-bit Encryption and it is capable of traversing network address translators (NATs) and firewalls. It allows computers to authenticate each other using a pre-shared secret key, certificates or username and password. This work gives review of VPN technology with a special accent on OpenVPN. This paper will also give comparison and financial benefits of using open source VPN software in business environment.

75 FR 49870 - Effects on Broadband Communications Networks of Damage to or Failure of Network Equipment or...

Federal Register 2010, 2011, 2012, 2013, 2014

2010-08-16

... FEDERAL COMMUNICATIONS COMMISSION 47 CFR Chapter I [PS Docket No. 10-92; DA 10-1357] Effects on Broadband Communications Networks of Damage to or Failure of Network Equipment or Severe Overload AGENCY: Federal Communications Commission ACTION: Proposed rule; extension of reply comment date. SUMMARY: This...

Towards a Community Environmental Observation Network

NASA Astrophysics Data System (ADS)

Mertl, Stefan; Lettenbichler, Anton

2014-05-01

The Community Environmental Observation Network (CEON) is dedicated to the development of a free sensor network to collect and distribute environmental data (e.g. ground shaking, climate parameters). The data collection will be done with contributions from citizens, research institutions and public authorities like communities or schools. This will lead to a large freely available data base which can be used for public information, research, the arts,..... To start a free sensor network, the most important step is to provide easy access to free data collection and -distribution tools. The initial aims of the project CEON are dedicated to the development of these tools. A high quality data logger based on open hardware and free software is developed and a software suite of already existing free software for near-real time data communication and data distribution over the Internet will be assembled. Foremost, the development focuses on the collection of data related to the deformation of the earth (such as ground shaking, surface displacement of mass movements and glaciers) and the collection of climate data. The extent to other measurements will be considered in the design. The data logger is built using open hardware prototyping platforms like BeagleBone Black and Arduino. Main features of the data logger are: a 24Bit analog-to-digital converter; a GPS module for time reference and positioning; wireless mesh networking using Optimized Link State Routing; near real-time data transmission and communication; and near real-time differential GNSS positioning using the RTKLIB software. The project CEON is supported by the Internet Foundation Austria (IPA) within the NetIdee 2013 call.

An information theory account of cognitive control.

PubMed

Fan, Jin

2014-01-01

Our ability to efficiently process information and generate appropriate responses depends on the processes collectively called cognitive control. Despite a considerable focus in the literature on the cognitive control of information processing, neural mechanisms underlying control are still unclear, and have not been characterized by considering the quantity of information to be processed. A novel and comprehensive account of cognitive control is proposed using concepts from information theory, which is concerned with communication system analysis and the quantification of information. This account treats the brain as an information-processing entity where cognitive control and its underlying brain networks play a pivotal role in dealing with conditions of uncertainty. This hypothesis and theory article justifies the validity and properties of such an account and relates experimental findings to the frontoparietal network under the framework of information theory.

Dynamic biosignal management and transmission during telemedicine incidents handled by Mobile Units over diverse network types.

PubMed

Mandellos, George J; Koutelakis, George V; Panagiotakopoulos, Theodor C; Koukias, Andreas M; Koukias, Mixalis N; Lymberopoulos, Dimitrios K

2008-01-01

Early and specialized pre-hospital patient treatment improves outcome in terms of mortality and morbidity, in emergency cases. This paper focuses on the design and implementation of a telemedicine system that supports diverse types of endpoints including moving transports (MT) (ambulances, ships, planes, etc.), handheld devices and fixed units, using diverse communication networks. Target of the above telemedicine system is the pre-hospital patient treatment. While vital sign transmission is prior to other services provided by the telemedicine system (videoconference, remote management, voice calls etc.), a predefined algorithm controls provision and quality of the other services. A distributed database system controlled by a central server, aims to manage patient attributes, exams and incidents handled by different Telemedicine Coordination Centers (TCC).

Reliable Communication Models in Interdependent Critical Infrastructure Networks

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

Lee, Sangkeun; Chinthavali, Supriya; Shankar, Mallikarjun

Modern critical infrastructure networks are becoming increasingly interdependent where the failures in one network may cascade to other dependent networks, causing severe widespread national-scale failures. A number of previous efforts have been made to analyze the resiliency and robustness of interdependent networks based on different models. However, communication network, which plays an important role in today's infrastructures to detect and handle failures, has attracted little attention in the interdependency studies, and no previous models have captured enough practical features in the critical infrastructure networks. In this paper, we study the interdependencies between communication network and other kinds of critical infrastructuremore » networks with an aim to identify vulnerable components and design resilient communication networks. We propose several interdependency models that systematically capture various features and dynamics of failures spreading in critical infrastructure networks. We also discuss several research challenges in building reliable communication solutions to handle failures in these models.« less

Data communications in a parallel active messaging interface of a parallel computer

DOEpatents

Archer, Charles J; Blocksome, Michael A; Ratterman, Joseph D; Smith, Brian E

2013-11-12

Data communications in a parallel active messaging interface (`PAMI`) of a parallel computer composed of compute nodes that execute a parallel application, each compute node including application processors that execute the parallel application and at least one management processor dedicated to gathering information regarding data communications. The PAMI is composed of data communications endpoints, each endpoint composed of a specification of data communications parameters for a thread of execution on a compute node, including specifications of a client, a context, and a task, the compute nodes and the endpoints coupled for data communications through the PAMI and through data communications resources. Embodiments function by gathering call site statistics describing data communications resulting from execution of data communications instructions and identifying in dependence upon the call cite statistics a data communications algorithm for use in executing a data communications instruction at a call site in the parallel application.

A Hybrid Satellite-Terrestrial Approach to Aeronautical Communication Networks

NASA Technical Reports Server (NTRS)

Kerczewski, Robert J.; Chomos, Gerald J.; Griner, James H.; Mainger, Steven W.; Martzaklis, Konstantinos S.; Kachmar, Brian A.

2000-01-01

Rapid growth in air travel has been projected to continue for the foreseeable future. To maintain a safe and efficient national and global aviation system, significant advances in communications systems supporting aviation are required. Satellites will increasingly play a critical role in the aeronautical communications network. At the same time, current ground-based communications links, primarily very high frequency (VHF), will continue to be employed due to cost advantages and legacy issues. Hence a hybrid satellite-terrestrial network, or group of networks, will emerge. The increased complexity of future aeronautical communications networks dictates that system-level modeling be employed to obtain an optimal system fulfilling a majority of user needs. The NASA Glenn Research Center is investigating the current and potential future state of aeronautical communications, and is developing a simulation and modeling program to research future communications architectures for national and global aeronautical needs. This paper describes the primary requirements, the current infrastructure, and emerging trends of aeronautical communications, including a growing role for satellite communications. The need for a hybrid communications system architecture approach including both satellite and ground-based communications links is explained. Future aeronautical communication network topologies and key issues in simulation and modeling of future aeronautical communications systems are described.

Overview of NASA communications infrastructure

NASA Technical Reports Server (NTRS)

Arnold, Ray J.; Fuechsel, Charles

1991-01-01

The infrastructure of NASA communications systems for effecting coordination across NASA offices and with the national and international research and technological communities is discussed. The offices and networks of the communication system include the Office of Space Science and Applications (OSSA), which manages all NASA missions, and the Office of Space Operations, which furnishes communication support through the NASCOM, the mission critical communications support network, and the Program Support Communications network. The NASA Science Internet was established by OSSA to centrally manage, develop, and operate an integrated computer network service dedicated to NASA's space science and application research. Planned for the future is the National Research and Education Network, which will provide communications infrastructure to enhance science resources at a national level.

GLOBECOM '85 - Global Telecommunications Conference, New Orleans, LA, December 2-5, 1985, Conference Record. Volumes 1, 2, & 3

NASA Astrophysics Data System (ADS)

Various papers on global telecommunications are presented. The general topics addressed include: multiservice integration with optical fibers, multicompany owned telecommunication networks, softworks quality and reliability, advanced on-board processing, impact of new services and systems on operations and maintenance, analytical studies of protocols for data communication networks, topics in packet radio networking, CCITT No. 7 to support new services, document processing and communication, antenna technology and system aspects in satellite communications. Also considered are: communication systems modelling methodology, experimental integrated local area voice/data nets, spread spectrum communications, motion video at the DS-0 rate, optical and data communications, intelligent work stations, switch performance analysis, novel radio communication systems, wireless local networks, ISDN services, LAN communication protocols, user-system interface, radio propagation and performance, mobile satellite system, software for computer networks, VLSI for ISDN terminals, quality management, man-machine interfaces in switching, and local area network performance.

Communication devices for network-hopping communications and methods of network-hopping communications

DOEpatents

Buttles, John W [Idaho Falls, ID

2011-12-20

Wireless communication devices include a software-defined radio coupled to processing circuitry. The processing circuitry is configured to execute computer programming code. Storage media is coupled to the processing circuitry and includes computer programming code configured to cause the processing circuitry to configure and reconfigure the software-defined radio to operate on each of a plurality of communication networks according to a selected sequence. Methods for communicating with a wireless device and methods of wireless network-hopping are also disclosed.

Communication devices for network-hopping communications and methods of network-hopping communications

DOEpatents

Buttles, John W

2013-04-23

Wireless communication devices include a software-defined radio coupled to processing circuitry. The system controller is configured to execute computer programming code. Storage media is coupled to the system controller and includes computer programming code configured to cause the system controller to configure and reconfigure the software-defined radio to operate on each of a plurality of communication networks according to a selected sequence. Methods for communicating with a wireless device and methods of wireless network-hopping are also disclosed.

GLOBECOM '87 - Global Telecommunications Conference, Tokyo, Japan, Nov. 15-18, 1987, Conference Record. Volumes 1, 2, & 3

NASA Astrophysics Data System (ADS)

The present conference on global telecommunications discusses topics in the fields of Integrated Services Digital Network (ISDN) technology field trial planning and results to date, motion video coding, ISDN networking, future network communications security, flexible and intelligent voice/data networks, Asian and Pacific lightwave and radio systems, subscriber radio systems, the performance of distributed systems, signal processing theory, satellite communications modulation and coding, and terminals for the handicapped. Also discussed are knowledge-based technologies for communications systems, future satellite transmissions, high quality image services, novel digital signal processors, broadband network access interface, traffic engineering for ISDN design and planning, telecommunications software, coherent optical communications, multimedia terminal systems, advanced speed coding, portable and mobile radio communications, multi-Gbit/second lightwave transmission systems, enhanced capability digital terminals, communications network reliability, advanced antimultipath fading techniques, undersea lightwave transmission, image coding, modulation and synchronization, adaptive signal processing, integrated optical devices, VLSI technologies for ISDN, field performance of packet switching, CSMA protocols, optical transport system architectures for broadband ISDN, mobile satellite communications, indoor wireless communication, echo cancellation in communications, and distributed network algorithms.

Terminal-oriented computer-communication networks.

NASA Technical Reports Server (NTRS)

Schwartz, M.; Boorstyn, R. R.; Pickholtz, R. L.

1972-01-01

Four examples of currently operating computer-communication networks are described in this tutorial paper. They include the TYMNET network, the GE Information Services network, the NASDAQ over-the-counter stock-quotation system, and the Computer Sciences Infonet. These networks all use programmable concentrators for combining a multiplicity of terminals. Included in the discussion for each network is a description of the overall network structure, the handling and transmission of messages, communication requirements, routing and reliability consideration where applicable, operating data and design specifications where available, and unique design features in the area of computer communications.

Virtual Wireless Sensor Networks: Adaptive Brain-Inspired Configuration for Internet of Things Applications

PubMed Central

Toyonaga, Shinya; Kominami, Daichi; Murata, Masayuki

2016-01-01

Many researchers are devoting attention to the so-called “Internet of Things” (IoT), and wireless sensor networks (WSNs) are regarded as a critical technology for realizing the communication infrastructure of the future, including the IoT. Against this background, virtualization is a crucial technique for the integration of multiple WSNs. Designing virtualized WSNs for actual environments will require further detailed studies. Within the IoT environment, physical networks can undergo dynamic change, and so, many problems exist that could prevent applications from running without interruption when using the existing approaches. In this paper, we show an overall architecture that is suitable for constructing and running virtual wireless sensor network (VWSN) services within a VWSN topology. Our approach provides users with a reliable VWSN network by assigning redundant resources according to each user’s demand and providing a recovery method to incorporate environmental changes. We tested this approach by simulation experiment, with the results showing that the VWSN network is reliable in many cases, although physical deployment of sensor nodes and the modular structure of the VWSN will be quite important to the stability of services within the VWSN topology. PMID:27548177

Virtual Wireless Sensor Networks: Adaptive Brain-Inspired Configuration for Internet of Things Applications.

PubMed

Toyonaga, Shinya; Kominami, Daichi; Murata, Masayuki

2016-08-19

Many researchers are devoting attention to the so-called "Internet of Things" (IoT), and wireless sensor networks (WSNs) are regarded as a critical technology for realizing the communication infrastructure of the future, including the IoT. Against this background, virtualization is a crucial technique for the integration of multiple WSNs. Designing virtualized WSNs for actual environments will require further detailed studies. Within the IoT environment, physical networks can undergo dynamic change, and so, many problems exist that could prevent applications from running without interruption when using the existing approaches. In this paper, we show an overall architecture that is suitable for constructing and running virtual wireless sensor network (VWSN) services within a VWSN topology. Our approach provides users with a reliable VWSN network by assigning redundant resources according to each user's demand and providing a recovery method to incorporate environmental changes. We tested this approach by simulation experiment, with the results showing that the VWSN network is reliable in many cases, although physical deployment of sensor nodes and the modular structure of the VWSN will be quite important to the stability of services within the VWSN topology.

Network Diversity and Affect Dynamics: The Role of Personality Traits

PubMed Central

Alshamsi, Aamena; Pianesi, Fabio; Lepri, Bruno; Pentland, Alex; Rahwan, Iyad

2016-01-01

People divide their time unequally among their social contacts due to time constraints and varying strength of relationships. It was found that high diversity of social communication, dividing time more evenly among social contacts, is correlated with economic well-being both at macro and micro levels. Besides economic well-being, it is not clear how the diversity of social communication is also associated with the two components of individuals’ subjective well-being, positive and negative affect. Specifically, positive affect and negative affect are two independent dimensions representing the experience (feeling) of emotions. In this paper, we investigate the relationship between the daily diversity of social communication and dynamic affect states that people experience in their daily lives. We collected two high-resolution datasets that capture affect scores via daily experience sampling surveys and social interaction through wearable sensing technologies: sociometric badges for face-to-face interaction and smart phones for mobile phone calls. We found that communication diversity correlates with desirable affect states–e.g. an increase in the positive affect state or a decrease in the negative affect state–for some personality types, but correlates with undesirable affect states for others. For example, diversity in phone calls is experienced as good by introverts, but bad by extroverts; diversity in face-to-face interaction is experienced as good by people who tend to be positive by nature (trait) but bad for people who tend to be not positive by nature. More broadly, the moderating effect of personality type on the relationship between diversity and affect was detected without any knowledge of the type of social tie or the content of communication. This provides further support for the power of unobtrusive sensing in understanding social dynamics, and in measuring the effect of potential interventions designed to improve well-being. PMID:27035904

Network Diversity and Affect Dynamics: The Role of Personality Traits.

PubMed

Alshamsi, Aamena; Pianesi, Fabio; Lepri, Bruno; Pentland, Alex; Rahwan, Iyad

2016-01-01

People divide their time unequally among their social contacts due to time constraints and varying strength of relationships. It was found that high diversity of social communication, dividing time more evenly among social contacts, is correlated with economic well-being both at macro and micro levels. Besides economic well-being, it is not clear how the diversity of social communication is also associated with the two components of individuals' subjective well-being, positive and negative affect. Specifically, positive affect and negative affect are two independent dimensions representing the experience (feeling) of emotions. In this paper, we investigate the relationship between the daily diversity of social communication and dynamic affect states that people experience in their daily lives. We collected two high-resolution datasets that capture affect scores via daily experience sampling surveys and social interaction through wearable sensing technologies: sociometric badges for face-to-face interaction and smart phones for mobile phone calls. We found that communication diversity correlates with desirable affect states--e.g. an increase in the positive affect state or a decrease in the negative affect state--for some personality types, but correlates with undesirable affect states for others. For example, diversity in phone calls is experienced as good by introverts, but bad by extroverts; diversity in face-to-face interaction is experienced as good by people who tend to be positive by nature (trait) but bad for people who tend to be not positive by nature. More broadly, the moderating effect of personality type on the relationship between diversity and affect was detected without any knowledge of the type of social tie or the content of communication. This provides further support for the power of unobtrusive sensing in understanding social dynamics, and in measuring the effect of potential interventions designed to improve well-being.

Different auditory feedback control for echolocation and communication in horseshoe bats.

PubMed

Liu, Ying; Feng, Jiang; Metzner, Walter

2013-01-01

Auditory feedback from the animal's own voice is essential during bat echolocation: to optimize signal detection, bats continuously adjust various call parameters in response to changing echo signals. Auditory feedback seems also necessary for controlling many bat communication calls, although it remains unclear how auditory feedback control differs in echolocation and communication. We tackled this question by analyzing echolocation and communication in greater horseshoe bats, whose echolocation pulses are dominated by a constant frequency component that matches the frequency range they hear best. To maintain echoes within this "auditory fovea", horseshoe bats constantly adjust their echolocation call frequency depending on the frequency of the returning echo signal. This Doppler-shift compensation (DSC) behavior represents one of the most precise forms of sensory-motor feedback known. We examined the variability of echolocation pulses emitted at rest (resting frequencies, RFs) and one type of communication signal which resembles an echolocation pulse but is much shorter (short constant frequency communication calls, SCFs) and produced only during social interactions. We found that while RFs varied from day to day, corroborating earlier studies in other constant frequency bats, SCF-frequencies remained unchanged. In addition, RFs overlapped for some bats whereas SCF-frequencies were always distinctly different. This indicates that auditory feedback during echolocation changed with varying RFs but remained constant or may have been absent during emission of SCF calls for communication. This fundamentally different feedback mechanism for echolocation and communication may have enabled these bats to use SCF calls for individual recognition whereas they adjusted RF calls to accommodate the daily shifts of their auditory fovea.

Different Auditory Feedback Control for Echolocation and Communication in Horseshoe Bats

PubMed Central

Liu, Ying; Feng, Jiang; Metzner, Walter

2013-01-01

Auditory feedback from the animal's own voice is essential during bat echolocation: to optimize signal detection, bats continuously adjust various call parameters in response to changing echo signals. Auditory feedback seems also necessary for controlling many bat communication calls, although it remains unclear how auditory feedback control differs in echolocation and communication. We tackled this question by analyzing echolocation and communication in greater horseshoe bats, whose echolocation pulses are dominated by a constant frequency component that matches the frequency range they hear best. To maintain echoes within this “auditory fovea”, horseshoe bats constantly adjust their echolocation call frequency depending on the frequency of the returning echo signal. This Doppler-shift compensation (DSC) behavior represents one of the most precise forms of sensory-motor feedback known. We examined the variability of echolocation pulses emitted at rest (resting frequencies, RFs) and one type of communication signal which resembles an echolocation pulse but is much shorter (short constant frequency communication calls, SCFs) and produced only during social interactions. We found that while RFs varied from day to day, corroborating earlier studies in other constant frequency bats, SCF-frequencies remained unchanged. In addition, RFs overlapped for some bats whereas SCF-frequencies were always distinctly different. This indicates that auditory feedback during echolocation changed with varying RFs but remained constant or may have been absent during emission of SCF calls for communication. This fundamentally different feedback mechanism for echolocation and communication may have enabled these bats to use SCF calls for individual recognition whereas they adjusted RF calls to accommodate the daily shifts of their auditory fovea. PMID:23638137

Communication networks in the brain: neurons, receptors, neurotransmitters, and alcohol.

PubMed

Lovinger, David M

2008-01-01

Nerve cells (i.e., neurons) communicate via a combination of electrical and chemical signals. Within the neuron, electrical signals driven by charged particles allow rapid conduction from one end of the cell to the other. Communication between neurons occurs at tiny gaps called synapses, where specialized parts of the two cells (i.e., the presynaptic and postsynaptic neurons) come within nanometers of one another to allow for chemical transmission. The presynaptic neuron releases a chemical (i.e., a neurotransmitter) that is received by the postsynaptic neuron's specialized proteins called neurotransmitter receptors. The neurotransmitter molecules bind to the receptor proteins and alter postsynaptic neuronal function. Two types of neurotransmitter receptors exist-ligand-gated ion channels, which permit rapid ion flow directly across the outer cell membrane, and G-protein-coupled receptors, which set into motion chemical signaling events within the cell. Hundreds of molecules are known to act as neurotransmitters in the brain. Neuronal development and function also are affected by peptides known as neurotrophins and by steroid hormones. This article reviews the chemical nature, neuronal actions, receptor subtypes, and therapeutic roles of several transmitters, neurotrophins, and hormones. It focuses on neurotransmitters with important roles in acute and chronic alcohol effects on the brain, such as those that contribute to intoxication, tolerance, dependence, and neurotoxicity, as well as maintained alcohol drinking and addiction.

Appplication of statistical mechanical methods to the modeling of social networks

NASA Astrophysics Data System (ADS)

Strathman, Anthony Robert

With the recent availability of large-scale social data sets, social networks have become open to quantitative analysis via the methods of statistical physics. We examine the statistical properties of a real large-scale social network, generated from cellular phone call-trace logs. We find this network, like many other social networks to be assortative (r = 0.31) and clustered (i.e., strongly transitive, C = 0.21). We measure fluctuation scaling to identify the presence of internal structure in the network and find that structural inhomogeneity effectively disappears at the scale of a few hundred nodes, though there is no sharp cutoff. We introduce an agent-based model of social behavior, designed to model the formation and dissolution of social ties. The model is a modified Metropolis algorithm containing agents operating under the basic sociological constraints of reciprocity, communication need and transitivity. The model introduces the concept of a social temperature. We go on to show that this simple model reproduces the global statistical network features (incl. assortativity, connected fraction, mean degree, clustering, and mean shortest path length) of the real network data and undergoes two phase transitions, one being from a "gas" to a "liquid" state and the second from a liquid to a glassy state as function of this social temperature.

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

Shwehdi, M.H.; Khan, A.Z.

Building automation technology is rapidly developing towards more reliable communication systems, devices that control electronic equipments. These equipment if controlled leads to efficient energy management, and savings on the monthly electricity bill. Power Line communication (PLC) has been one of the dreams of the electronics industry for decades, especially for building automation. It is the purpose of this paper to demonstrate communication methods among electronic control devices through an AC power line carrier within the buildings for more efficient energy control. The paper outlines methods of communication over a powerline, namely the X-10 and CE bus. It also introduces themore » spread spectrum technology as to increase speed to 100--150 times faster than the X-10 system. The powerline carrier has tremendous applications in the field of building automation. The paper presents an attempt to realize a smart house concept, so called, in which all home electronic devices from a coffee maker to a water heater microwave to chaos robots will be utilized by an intelligent network whenever one wishes to do so. The designed system may be applied very profitably to help in energy management for both customer and utility.« less

Determining a bisection bandwidth for a multi-node data communications network

DOEpatents

Faraj, Ahmad A.

2010-01-26

Methods, systems, and products are disclosed for determining a bisection bandwidth for a multi-node data communications network that include: partitioning nodes in the network into a first sub-network and a second sub-network in dependence upon a topology of the network; sending, by each node in the first sub-network to a destination node in the second sub-network, a first message having a predetermined message size; receiving, by each node in the first sub-network from a source node in the second sub-network, a second message; measuring, by each node in the first sub-network, the elapsed communications time between the sending of the first message and the receiving of the second message; selecting the longest elapsed communications time; and calculating the bisection bandwidth for the network in dependence upon the number of the nodes in the first sub-network, the predetermined message size of the first test message, and the longest elapsed communications time.

Automatic analysis of attack data from distributed honeypot network

NASA Astrophysics Data System (ADS)

Safarik, Jakub; Voznak, MIroslav; Rezac, Filip; Partila, Pavol; Tomala, Karel

2013-05-01

There are many ways of getting real data about malicious activity in a network. One of them relies on masquerading monitoring servers as a production one. These servers are called honeypots and data about attacks on them brings us valuable information about actual attacks and techniques used by hackers. The article describes distributed topology of honeypots, which was developed with a strong orientation on monitoring of IP telephony traffic. IP telephony servers can be easily exposed to various types of attacks, and without protection, this situation can lead to loss of money and other unpleasant consequences. Using a distributed topology with honeypots placed in different geological locations and networks provides more valuable and independent results. With automatic system of gathering information from all honeypots, it is possible to work with all information on one centralized point. Communication between honeypots and centralized data store use secure SSH tunnels and server communicates only with authorized honeypots. The centralized server also automatically analyses data from each honeypot. Results of this analysis and also other statistical data about malicious activity are simply accessible through a built-in web server. All statistical and analysis reports serve as information basis for an algorithm which classifies different types of used VoIP attacks. The web interface then brings a tool for quick comparison and evaluation of actual attacks in all monitored networks. The article describes both, the honeypots nodes in distributed architecture, which monitor suspicious activity, and also methods and algorithms used on the server side for analysis of gathered data.

Reengineering the picture archiving and communication system (PACS) process for digital imaging networks PACS.

PubMed

Horton, M C; Lewis, T E; Kinsey, T V

1999-05-01

Prior to June 1997, military picture archiving and communications systems (PACS) were planned, procured, and installed with key decisions on the system, equipment, and even funding sources made through a research and development office called Medical Diagnostic Imaging Systems (MDIS). Beginning in June 1997, the Joint Imaging Technology Project Office (JITPO) initiated a collaborative and consultative process for planning and implementing PACS into military treatment facilities through a new Department of Defense (DoD) contract vehicle called digital imaging networks (DIN)-PACS. The JITPO reengineered this process incorporating multiple organizations and politics. The reengineered PACS process administered through the JITPO transformed the decision process and accountability from a single office to a consultative method that increased end-user knowledge, responsibility, and ownership in PACS. The JITPO continues to provide information and services that assist multiple groups and users in rendering PACS planning and implementation decisions. Local site project managers are involved from the outset and this end-user collaboration has made the sometimes difficult transition to PACS an easier and more acceptable process for all involved. Corporately, this process saved DoD sites millions by having PACS plans developed within the government and proposed to vendors second, and then having vendors respond specifically to those plans. The integrity and efficiency of the process have reduced the opportunity for implementing nonstandard systems while sharing resources and reducing wasted government dollars. This presentation will describe the chronology of changes, encountered obstacles, and lessons learned within the reengineering of the PACS process for DIN-PACS.

ACTS Aeronautical Terminal Experiment (AERO-X)

NASA Technical Reports Server (NTRS)

1995-01-01

During the summer of 1994, the performance of an experimental mobile satellite communication system was demonstrated. Using the Advanced Communications Technology Satellite (ACTS) and the ACTS Mobile Terminal (AMT), the system demonstrated an active Monolithic Microwave Integrated Circuit (MMIC) phased-array antenna system. The antenna system was installed onboard one of NASA Lewis Research Center's research aircraft, a Learjet Model 25. It proved the viability of in-flight satellite communications services via small, flush, mountable electronic phased-array antennas. The overall system setup for the ACTS Aeronautical Terminal Experiment (AERO-X) is illustrated. The Link Evaluation Terminal (LET) at Lewis in Cleveland, Ohio, interfaced with fixed-AMT equipment, providing a seamless connection with the Public Service Telephone Network. As the Learjet was flown over several major cities across the U.S., this demonstration system allowed passengers onboard to make telephone calls as if they were using a cellular system. ACTS was operated in its microwave switch matrix mode with a spot beam for the Learjet and another spot beam dedicated to the LET.

Design and Test of an Event Detector for the ReflectoActive Seals System

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

Stinson, Brad J

2006-05-01

The purpose of this thesis was to research, design, develop and test a novel instrument for detecting fiber optic loop continuity and spatially locating fiber optic breaches. The work is for an active seal system called ReflectoActive Seals whose purpose is to provide real time container tamper indication. A Field Programmable Gate Array was used to implement a loop continuity detector and a spatial breach locator based on a high acquisition speed single photon counting optical time domain reflectometer. Communication and other control features were added in order to create a usable instrument that met defined requirements. A host graphicalmore » user interface was developed to illustrate system use and performance. The resulting device meets performance specifications by exhibiting a dynamic range of 27dB and a spatial resolution of 1.5 ft. The communication scheme used expands installation options and allows the device to communicate to a central host via existing Local Area Networks and/or the Internet.« less

Design and Test of an Event Detector and Locator for the ReflectoActive Seals System

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

Stinson, Brad J

2006-06-01

The purpose of this work was to research, design, develop and test a novel instrument for detecting fiber optic loop continuity and spatially locating fiber optic breaches. The work is for an active seal system called ReflectoActive{trademark} Seals whose purpose is to provide real time container tamper indication. A Field Programmable Gate Array was used to implement a loop continuity detector and a spatial breach locator based on a high acquisition speed single photon counting optical time domain reflectometer. Communication and other control features were added in order to create a usable instrument that met defined requirements. A host graphicalmore » user interface was developed to illustrate system use and performance. The resulting device meets performance specifications by exhibiting a dynamic range of 27dB and a spatial resolution of 1.5 ft. The communication scheme used expands installation options and allows the device to communicate to a central host via existing Local Area Networks and/or the Internet.« less

Integrating Communication and Navigation: Next Generation Broadcast Service (NGBS)

NASA Technical Reports Server (NTRS)

Donaldson, Jennifer

2017-01-01

NASA Goddard has been investing in technology demonstrations of a beacon service, now called Next Generation Broadcast Services (NGBS). NGBS is a global, space-based, communications and navigation service for users of Global Navigation Satellite Systems (GNSS) and the Tracking and Data Relay Satellite System (TDRSS). NGBS will provide an S-band beacon messaging source and radio navigation available to users at orbital altitudes 1400 km and below, increasing the autonomy and resiliency of onboard communication and navigation. NGBS will deliver both one-way radiometric (Doppler and pseudorange) and fast forward data transport services to users. Portions of the overall forward data volume will be allocated for fixed message types while the remaining data volume will be left for user forward command data. The NGBS signal will reside within the 2106.43 MHz spectrum currently allocated for the Space Networks multiple access forward (MAF) service and a live service demonstration is currently being planned via the 2nd and 3rd generation TDRS satellites.

Research on social communication network evolution based on topology potential distribution

NASA Astrophysics Data System (ADS)

Zhao, Dongjie; Jiang, Jian; Li, Deyi; Zhang, Haisu; Chen, Guisheng

2011-12-01

Aiming at the problem of social communication network evolution, first, topology potential is introduced to measure the local influence among nodes in networks. Second, from the perspective of topology potential distribution the method of network evolution description based on topology potential distribution is presented, which takes the artificial intelligence with uncertainty as basic theory and local influence among nodes as essentiality. Then, a social communication network is constructed by enron email dataset, the method presented is used to analyze the characteristic of the social communication network evolution and some useful conclusions are got, implying that the method is effective, which shows that topology potential distribution can effectively describe the characteristic of sociology and detect the local changes in social communication network.

Ring-like reliable PON planning with physical constraints for a smart grid

NASA Astrophysics Data System (ADS)

Wang, Xin; Gu, Rentao; Ji, Yuefeng

2016-01-01

Due to the high reliability requirements in the communication networks of a smart grid, a ring-like reliable PON is an ideal choice to carry power distribution information. Economical network planning is also very important for the smart grid communication infrastructure. Although the ring-like reliable PON has been widely used in the real applications, as far as we know, little research has been done on the network optimization subject of the ring-like reliable PON. Most PON planning research studies only consider a star-like topology or cascaded PON network, which barely guarantees the reliability requirements of the smart grid. In this paper, we mainly investigate the economical network planning problem for the ring-like reliable PON of the smart grid. To address this issue, we built a mathematical model for the planning problem of the ring-like reliable PON, and the objective was to minimize the total deployment costs under physical constraints. The model is simplified such that all of the nodes have the same properties, except OLT, because each potential splitter site can be located in the same ONU position in power communication networks. The simplified model is used to construct an optimal main tree topology in the complete graph and a backup-protected tree topology in the residual graph. An efficient heuristic algorithm, called the Constraints and Minimal Weight Oriented Fast Searching Algorithm (CMW-FSA), is proposed. In CMW-FSA, a feasible solution can be obtained directly with oriented constraints and a few recursive search processes. From the simulation results, the proposed planning model and CMW-FSA are verified to be accurate (the error rates are less than 0.4%) and effective compared with the accurate solution (CAESA), especially in small and sparse scenarios. The CMW-FSA significantly reduces the computation time compared with the CAESA. The time complexity algorithm of the CMW-FSA is acceptable and calculated as T(n) = O(n3). After evaluating the effects of the parameters of the two PON systems, the total planning costs of each scenario show a general declining trend and reach a threshold as the respective maximal transmission distances and maximal time delays increase.

Biophoton signal transmission and processing in the brain.

PubMed

Tang, Rendong; Dai, Jiapei

2014-10-05

The transmission and processing of neural information in the nervous system plays a key role in neural functions. It is well accepted that neural communication is mediated by bioelectricity and chemical molecules via the processes called bioelectrical and chemical transmission, respectively. Indeed, the traditional theories seem to give valuable explanations for the basic functions of the nervous system, but difficult to construct general accepted concepts or principles to provide reasonable explanations of higher brain functions and mental activities, such as perception, learning and memory, emotion and consciousness. Therefore, many unanswered questions and debates over the neural encoding and mechanisms of neuronal networks remain. Cell to cell communication by biophotons, also called ultra-weak photon emissions, has been demonstrated in several plants, bacteria and certain animal cells. Recently, both experimental evidence and theoretical speculation have suggested that biophotons may play a potential role in neural signal transmission and processing, contributing to the understanding of the high functions of nervous system. In this paper, we review the relevant experimental findings and discuss the possible underlying mechanisms of biophoton signal transmission and processing in the nervous system. Copyright © 2014 Elsevier B.V. All rights reserved.

An IMS-Based Middleware Solution for Energy-Efficient and Cost-Effective Mobile Multimedia Services

NASA Astrophysics Data System (ADS)

Bellavista, Paolo; Corradi, Antonio; Foschini, Luca

Mobile multimedia services have recently become of extreme industrial relevance due to the advances in both wireless client devices and multimedia communications. That has motivated important standardization efforts, such as the IP Multimedia Subsystem (IMS) to support session control, mobility, and interoperability in all-IP next generation networks. Notwithstanding the central role of IMS in novel mobile multimedia, the potential of IMS-based service composition for the development of new classes of ready-to-use, energy-efficient, and cost-effective services is still widely unexplored. The paper proposes an original solution for the dynamic and standard-compliant redirection of incoming voice calls towards WiFi-equipped smart phones. The primary design guideline is to reduce energy consumption and service costs for the final user by automatically switching from the 3G to the WiFi infrastructure whenever possible. The proposal is fully compliant with the IMS standard and exploits the recently released IMS presence service to update device location and current communication opportunities. The reported experimental results point out that our solution, in a simple way and with full compliance with state-of-the-art industrially-accepted standards, can significantly increase battery lifetime without negative effects on call initiation delay.

WindTalker: A P2P-Based Low-Latency Anonymous Communication Network

NASA Astrophysics Data System (ADS)

Zhang, Jia; Duan, Haixin; Liu, Wu; Wu, Jianping

Compared with traditional static anonymous communication networks, the P2P architecture can provide higher anonymity in communication. However, the P2P architecture also leads to more challenges, such as route, stability, trust and so on. In this paper, we present WindTalker, a P2P-based low-latency anonymous communication network. It is a pure decentralized mix network and can provide low-latency services which help users hide their real identity in communication. In order to ensure stability and reliability, WindTalker imports “seed nodes” to help a peer join in the P2P network and the peer nodes can use gossip-based protocol to exchange active information. Moreover, WindTalker uses layer encryption to ensure the information of relayed messages cannot be leaked. In addition, malicious nodes in the network are the major threat to anonymity of P2P anonymous communication, so WindTalker imports a trust mechanism which can help the P2P network exclude malicious nodes and optimize the strategy of peer discovery, tunnel construction, and relaying etc. in anonymous communications. We deploy peer nodes of WindTalker in our campus network to test reliability and analyze anonymity in theory. The network measurement and simulation analysis shows that WindTalker can provide low-latency and reliable anonymous communication services.

An Improved Call Admission Control Mechanism with Prioritized Handoff Queuing Scheme for BWA Networks

NASA Astrophysics Data System (ADS)

Chowdhury, Prasun; Saha Misra, Iti

2014-10-01

Nowadays, due to increased demand for using the Broadband Wireless Access (BWA) networks in a satisfactory manner a promised Quality of Service (QoS) is required to manage the seamless transmission of the heterogeneous handoff calls. To this end, this paper proposes an improved Call Admission Control (CAC) mechanism with prioritized handoff queuing scheme that aims to reduce dropping probability of handoff calls. Handoff calls are queued when no bandwidth is available even after the allowable bandwidth degradation of the ongoing calls and get admitted into the network when an ongoing call is terminated with a higher priority than the newly originated call. An analytical Markov model for the proposed CAC mechanism is developed to analyze various performance parameters. Analytical results show that our proposed CAC with handoff queuing scheme prioritizes the handoff calls effectively and reduces dropping probability of the system by 78.57% for real-time traffic without degrading the number of failed new call attempts. This results in the increased bandwidth utilization of the network.

Expected number of quantum channels in quantum networks.

PubMed

Chen, Xi; Wang, He-Ming; Ji, Dan-Tong; Mu, Liang-Zhu; Fan, Heng

2015-07-15

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.

Expected number of quantum channels in quantum networks

PubMed Central

Chen, Xi; Wang, He-Ming; Ji, Dan-Tong; Mu, Liang-Zhu; Fan, Heng

2015-01-01

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. PMID:26173556

Reconfigureable network node

DOEpatents

Vanderveen, Keith B [Tracy, CA; Talbot, Edward B [Livermore, CA; Mayer, Laurence E [Davis, CA

2008-04-08

Nodes in a network having a plurality of nodes establish communication links with other nodes using available transmission media, as the ability to establish such links becomes available and desirable. The nodes predict when existing communications links will fail, become overloaded or otherwise degrade network effectiveness and act to establish substitute or additional links before the node's ability to communicate with the other nodes on the network is adversely affected. A node stores network topology information and programmed link establishment rules and criteria. The node evaluates characteristics that predict existing links with other nodes becoming unavailable or degraded. The node then determines whether it can form a communication link with a substitute node, in order to maintain connectivity with the network. When changing its communication links, a node broadcasts that information to the network. Other nodes update their stored topology information and consider the updated topology when establishing new communications links for themselves.

Parallel processing data network of master and slave transputers controlled by a serial control network

DOEpatents

Crosetto, D.B.

1996-12-31

The present device provides for a dynamically configurable communication network having a multi-processor parallel processing system having a serial communication network and a high speed parallel communication network. The serial communication network is used to disseminate commands from a master processor to a plurality of slave processors to effect communication protocol, to control transmission of high density data among nodes and to monitor each slave processor`s status. The high speed parallel processing network is used to effect the transmission of high density data among nodes in the parallel processing system. Each node comprises a transputer, a digital signal processor, a parallel transfer controller, and two three-port memory devices. A communication switch within each node connects it to a fast parallel hardware channel through which all high density data arrives or leaves the node. 6 figs.

Parallel processing data network of master and slave transputers controlled by a serial control network

DOEpatents

Crosetto, Dario B.

1996-01-01

The present device provides for a dynamically configurable communication network having a multi-processor parallel processing system having a serial communication network and a high speed parallel communication network. The serial communication network is used to disseminate commands from a master processor (100) to a plurality of slave processors (200) to effect communication protocol, to control transmission of high density data among nodes and to monitor each slave processor's status. The high speed parallel processing network is used to effect the transmission of high density data among nodes in the parallel processing system. Each node comprises a transputer (104), a digital signal processor (114), a parallel transfer controller (106), and two three-port memory devices. A communication switch (108) within each node (100) connects it to a fast parallel hardware channel (70) through which all high density data arrives or leaves the node.

Communication Characterization and Optimization of Applications Using Topology-Aware Task Mapping on Large Supercomputers

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

Sreepathi, Sarat; D'Azevedo, Eduardo; Philip, Bobby

On large supercomputers, the job scheduling systems may assign a non-contiguous node allocation for user applications depending on available resources. With parallel applications using MPI (Message Passing Interface), the default process ordering does not take into account the actual physical node layout available to the application. This contributes to non-locality in terms of physical network topology and impacts communication performance of the application. In order to mitigate such performance penalties, this work describes techniques to identify suitable task mapping that takes the layout of the allocated nodes as well as the application's communication behavior into account. During the first phasemore » of this research, we instrumented and collected performance data to characterize communication behavior of critical US DOE (United States - Department of Energy) applications using an augmented version of the mpiP tool. Subsequently, we developed several reordering methods (spectral bisection, neighbor join tree etc.) to combine node layout and application communication data for optimized task placement. We developed a tool called mpiAproxy to facilitate detailed evaluation of the various reordering algorithms without requiring full application executions. This work presents a comprehensive performance evaluation (14,000 experiments) of the various task mapping techniques in lowering communication costs on Titan, the leadership class supercomputer at Oak Ridge National Laboratory.« less

Interns overestimate the effectiveness of their hand-off communication.

PubMed

Chang, Vivian Y; Arora, Vineet M; Lev-Ari, Shiri; D'Arcy, Michael; Keysar, Boaz

2010-03-01

Theories from the psychology of communication may be applicable in understanding why hand-off communication is inherently problematic. The purpose of this study was to assess whether postcall pediatric interns can correctly estimate the patient care information and rationale received by on-call interns during hand-off communication. Pediatric interns at the University of Chicago were interviewed about the hand-off. Postcall interns were asked to predict what on-call interns would report as the important pieces of information communicated during the hand-off about each patient, with accompanying rationale. Postcall interns also guessed on-call interns' rating of how well the hand-offs went. Then, on-call interns were asked to list the most important pieces of information for each patient that postcall interns communicated during the hand-off, with accompanying rationale. On-call interns also rated how well the hand-offs went. Interns had access to written hand-offs during the interviews. We conducted 52 interviews, which constituted 59% of eligible interviews. Seventy-two patients were discussed. The most important piece of information about a patient was not successfully communicated 60% of the time, despite the postcall intern's believing that it was communicated. Postcall and on-call interns did not agree on the rationales provided for 60% of items. In addition, an item was more likely to be effectively communicated when it was a to-do item (65%) or an item related to anticipatory guidance (69%) compared with a knowledge item (38%). Despite the lack of agreement on content and rationale of information communicated during hand-offs, peer ratings of hand-off quality were high. Pediatric interns overestimated the effectiveness of their hand-off communication. Theories from communication psychology suggest that miscommunication is caused by egocentric thought processes and a tendency for the speaker to overestimate the receiver's understanding. This study demonstrates that systematic causes of miscommunication may play a role in hand-off quality.

Communication, advice exchange and job satisfaction of nursing staff: a social network analyses of 35 long-term care units.

PubMed

van Beek, Adriana P A; Wagner, Cordula; Spreeuwenberg, Peter P M; Frijters, Dinnus H M; Ribbe, Miel W; Groenewegen, Peter P

2011-06-01

The behaviour of individuals is affected by the social networks in which they are embedded. Networks are also important for the diffusion of information and the influence of employees in organisations. Yet, at the moment little is known about the social networks of nursing staff in healthcare settings. This is the first study that investigates informal communication and advice networks of nursing staff in long-term care. We examine the structure of the networks, how they are related to the size of units and characteristics of nursing staff, and their relationship with job satisfaction. We collected social network data of 380 nursing staff of 35 units in group projects and psychogeriatric units in nursing homes and residential homes in the Netherlands. Communication and advice networks were analyzed in a social network application (UCINET), focusing on the number of contacts (density) between nursing staff on the units. We then studied the correlation between the density of networks, size of the units and characteristics of nursing staff. We used multilevel analyses to investigate the relationship between social networks and job satisfaction of nursing staff, taking characteristics of units and nursing staff into account. Both communication and advice networks were negatively related to the number of residents and the number of nursing staff of the units. Communication and advice networks were more dense when more staff worked part-time. Furthermore, density of communication networks was positively related to the age of nursing staff of the units. Multilevel analyses showed that job satisfaction differed significantly between individual staff members and units and was influenced by the number of nursing staff of the units. However, this relationship disappeared when density of communication networks was added to the model. Overall, communication and advice networks of nursing staff in long-term care are relatively dense. This fits with the high level of cooperation that is needed to provide good care to residents. Social networks are more dense in small units and are also shaped by characteristics of staff members. The results furthermore show that communication networks are important for staff's job satisfaction.

Communication, advice exchange and job satisfaction of nursing staff: a social network analyses of 35 long-term care units

PubMed Central

2011-01-01

Background The behaviour of individuals is affected by the social networks in which they are embedded. Networks are also important for the diffusion of information and the influence of employees in organisations. Yet, at the moment little is known about the social networks of nursing staff in healthcare settings. This is the first study that investigates informal communication and advice networks of nursing staff in long-term care. We examine the structure of the networks, how they are related to the size of units and characteristics of nursing staff, and their relationship with job satisfaction. Methods We collected social network data of 380 nursing staff of 35 units in group projects and psychogeriatric units in nursing homes and residential homes in the Netherlands. Communication and advice networks were analyzed in a social network application (UCINET), focusing on the number of contacts (density) between nursing staff on the units. We then studied the correlation between the density of networks, size of the units and characteristics of nursing staff. We used multilevel analyses to investigate the relationship between social networks and job satisfaction of nursing staff, taking characteristics of units and nursing staff into account. Results Both communication and advice networks were negatively related to the number of residents and the number of nursing staff of the units. Communication and advice networks were more dense when more staff worked part-time. Furthermore, density of communication networks was positively related to the age of nursing staff of the units. Multilevel analyses showed that job satisfaction differed significantly between individual staff members and units and was influenced by the number of nursing staff of the units. However, this relationship disappeared when density of communication networks was added to the model. Conclusions Overall, communication and advice networks of nursing staff in long-term care are relatively dense. This fits with the high level of cooperation that is needed to provide good care to residents. Social networks are more dense in small units and are also shaped by characteristics of staff members. The results furthermore show that communication networks are important for staff's job satisfaction. PMID:21631936

All about Eve: Secret Sharing using Quantum Effects

NASA Technical Reports Server (NTRS)

Jackson, Deborah J.

2005-01-01

This document discusses the nature of light (including classical light and photons), encryption, quantum key distribution (QKD), light polarization and beamsplitters and their application to information communication. A quantum of light represents the smallest possible subdivision of radiant energy (light) and is called a photon. The QKD key generation sequence is outlined including the receiver broadcasting the initial signal indicating reception availability, timing pulses from the sender to provide reference for gated detection of photons, the sender generating photons through random polarization while the receiver detects photons with random polarization and communicating via data link to mutually establish random keys. The QKD network vision includes inter-SATCOM, point-to-point Gnd Fiber and SATCOM-fiber nodes. QKD offers an unconditionally secure method of exchanging encryption keys. Ongoing research will focus on how to increase the key generation rate.

A development framework for distributed artificial intelligence

NASA Technical Reports Server (NTRS)

Adler, Richard M.; Cottman, Bruce H.

1989-01-01

The authors describe distributed artificial intelligence (DAI) applications in which multiple organizations of agents solve multiple domain problems. They then describe work in progress on a DAI system development environment, called SOCIAL, which consists of three primary language-based components. The Knowledge Object Language defines models of knowledge representation and reasoning. The metaCourier language supplies the underlying functionality for interprocess communication and control access across heterogeneous computing environments. The metaAgents language defines models for agent organization coordination, control, and resource management. Application agents and agent organizations will be constructed by combining metaAgents and metaCourier building blocks with task-specific functionality such as diagnostic or planning reasoning. This architecture hides implementation details of communications, control, and integration in distributed processing environments, enabling application developers to concentrate on the design and functionality of the intelligent agents and agent networks themselves.

WINDS (KIZUNA)-based Collaborative e-Learning Project in Thailand, Malaysia and Japan

NASA Astrophysics Data System (ADS)

Hisanaga, Makoto; Takahashi, Shin; Kameyama, Keisuke; Fukui, Yukio; Kitawaki, Nobuhiko

The expanding digital divide deprives students in developing countries with opportunities for education. Advanced countries have the ability to enhance those opportunities. For this study, the authors set up and tested a remote lecture system using a commercial communication satellite beginning in 2002. This project attempted to solve issues in remote lecture systems using conventional satellite systems, and to build up a real-time collaborative lecture delivery system using a new satellite, called the Wideband InterNetworking engineering test and Demonstration Satellite (WINDS). This work proposes a remote education system using satellites, enabling the issues raised in the pilot experiments to be solved. Principal outcomes in this project include improvements of the quality of image and sound, and the communication delay. The authors also demonstrate the usefulness of WINDS in the education field.

Audio CAPTCHA for SIP-Based VoIP

NASA Astrophysics Data System (ADS)

Soupionis, Yannis; Tountas, George; Gritzalis, Dimitris

Voice over IP (VoIP) introduces new ways of communication, while utilizing existing data networks to provide inexpensive voice communications worldwide as a promising alternative to the traditional PSTN telephony. SPam over Internet Telephony (SPIT) is one potential source of future annoyance in VoIP. A common way to launch a SPIT attack is the use of an automated procedure (bot), which generates calls and produces audio advertisements. In this paper, our goal is to design appropriate CAPTCHA to fight such bots. We focus on and develop audio CAPTCHA, as the audio format is more suitable for VoIP environments and we implement it in a SIP-based VoIP environment. Furthermore, we suggest and evaluate the specific attributes that audio CAPTCHA should incorporate in order to be effective, and test it against an open source bot implementation.

Requirements for a network storage service

NASA Technical Reports Server (NTRS)

Kelly, Suzanne M.; Haynes, Rena A.

1991-01-01

Sandia National Laboratories provides a high performance classified computer network as a core capability in support of its mission of nuclear weapons design and engineering, physical sciences research, and energy research and development. The network, locally known as the Internal Secure Network (ISN), comprises multiple distributed local area networks (LAN's) residing in New Mexico and California. The TCP/IP protocol suite is used for inter-node communications. Scientific workstations and mid-range computers, running UNIX-based operating systems, compose most LAN's. One LAN, operated by the Sandia Corporate Computing Computing Directorate, is a general purpose resource providing a supercomputer and a file server to the entire ISN. The current file server on the supercomputer LAN is an implementation of the Common File Server (CFS). Subsequent to the design of the ISN, Sandia reviewed its mass storage requirements and chose to enter into a competitive procurement to replace the existing file server with one more adaptable to a UNIX/TCP/IP environment. The requirements study for the network was the starting point for the requirements study for the new file server. The file server is called the Network Storage Service (NSS) and its requirements are described. An application or functional description of the NSS is given. The final section adds performance, capacity, and access constraints to the requirements.

Unobstructive Body Area Networks (BAN) for Efficient Movement Monitoring

PubMed Central

Felisberto, Filipe; Costa, Nuno; Fdez-Riverola, Florentino; Pereira, António

2012-01-01

The technological advances in medical sensors, low-power microelectronics and miniaturization, wireless communications and networks have enabled the appearance of a new generation of wireless sensor networks: the so-called wireless body area networks (WBAN). These networks can be used for continuous monitoring of vital parameters, movement, and the surrounding environment. The data gathered by these networks contributes to improve users' quality of life and allows the creation of a knowledge database by using learning techniques, useful to infer abnormal behaviour. In this paper we present a wireless body area network architecture to recognize human movement, identify human postures and detect harmful activities in order to prevent risk situations. The WBAN was created using tiny, cheap and low-power nodes with inertial and physiological sensors, strategically placed on the human body. Doing so, in an as ubiquitous as possible way, ensures that its impact on the users' daily actions is minimum. The information collected by these sensors is transmitted to a central server capable of analysing and processing their data. The proposed system creates movement profiles based on the data sent by the WBAN's nodes, and is able to detect in real time any abnormal movement and allows for a monitored rehabilitation of the user. PMID:23112726

US long distance fiber optic networks: Technology, evolution and advanced concepts. Volume 1: Executive summary

NASA Technical Reports Server (NTRS)

1986-01-01

Over the past two decades, fiber optics has emerged as a highly practical and cost-efficient communications technology. Its competitiveness vis-a-vis other transmission media, especially satellite, has become a critical question. This report studies the likely evolution and application of fiber optic networks in the United States to the end of the century. The outlook for the technology of fiber systems is assessed and forecast, scenarios of the evolution of fiber optic network development are constructed, and costs to provide service are determined and examined parametrically as a function of network size and traffic carried. Volume 1 consists of the Executive Summary. Volume 2 focuses on fiber optic technology and long distance fiber optic networks. Volume 3 develops a traffic and financial model of a nationwide long distance transmission network. Among the study's most important conclusions are: revenue requirements per circuit for LATA-to-LATA fiber optic links are less than one cent per call minute; multiplex equipment, which is likely to be required in any competing system, is the largest contributor to circuit costs; the potential capacity of fiber optic cable is very large and as yet undefined; and fiber optic transmission combined with other network optimization schemes can lead to even lower costs than those identified in this study.

Super-dense teleportation for space applications

NASA Astrophysics Data System (ADS)

Zeitler, Chris; Graham, Trent M.; Chapman, Joseph; Bernstein, Herbert; Kwiat, Paul G.

2016-03-01

Establishing a quantum communication network would provide advantages in areas such as security and information processing. Such a network would require the implementation of quantum teleportation between remote parties. However, for photonic "qudits" of dimension greater than two, this teleportation always fails due to the inability to carry out the required quantum Bell-state measurement. A quantum communication protocol called Superdense Teleportation (SDT) can allow the reconstruction of a state without the usual 2-photon Bell-state measurements, enabling the protocol to succeed deterministically even for high dimensional qudits. This technique restricts the class of states transferred to equimodular states, a type of superposition state where each term can differ from the others in phase but not in amplitude; this restricted space of transmitted states allows the transfer to occur deterministically. We report on our implementation of SDT using photon pairs that are entangled in both polarization and temporal mode. After encoding the phases of the desired equimodular state on the signal photon, we perform a complete tomography on the idler photon to verify that we properly prepared the chosen state. Beyond our tabletop demonstration, we are working towards an implementation between a space platform in low earth orbit and a ground telescope, to demonstrate the feasibility of space-based quantum communication. We will discuss the various challenges presented by moving the experiment out of the laboratory, and our proposed solutions to make Superdense Teleportation realizable in the space setting.

Jana: Confidential Communications on Social Networks

DTIC Science & Technology

2017-08-09

Report: Jana: Confidential Communications on Social Networks The views, opinions and/or findings contained in this report are those of the author(s) and...Confidential Communications on Social Networks Report Term: 0-Other Email: krish@ucr.edu Distribution Statement: 1-Approved for public release; distribution...is unlimited. Major Goals: The inability of users to communicate secretly on online social networking (OSN) platforms is a key obstacle to overcome

The Virtual Research and Extension Communication Network (VRECN): An Interactive Learning and Communication Network for Research and Extension Personnel. Concept Paper for the Food & Agriculture Organisation of the United Nations (FAO).

ERIC Educational Resources Information Center

Richardson, Don

A Virtual Research and Extension Communication Network (VRECN) is a set of networked electronic tools facilitating improvement in communication processes and information sharing among stakeholders involved in agricultural development. In developing countries, research and extension personnel within a ministry of agriculture, in consultation and…

Final Environmental Assessment for Wide Area Coverage Construct Land Mobile Network Communications Infrastructure Malmstrom Air Force Base, Montana

DTIC Science & Technology

2008-02-01

FINAL ENVIRONMENTAL ASSESSMENT February 2008 Malmstrom ® AFB WIDE AREA COVERAGE CONSTRUCT LAND MOBILE NETWORK COMMUNICATIONS INFRASTRUCTURE...Wide Area Coverage Construct Land Mobile Network Communications Infrastructure Malmstrom Air Force Base, Montana 5a. CONTRACT NUMBER 5b. GRANT...SIGNIFICANT IMPACT WIDE AREA COVERAGE CONSTRUCT LAND MOBILE NETWORK COMMUNICATIONS INFRASTRUCTURE MALMSTROM AIR FORCE BASE, MONTANA The

High-Performance Satellite/Terrestrial-Network Gateway

NASA Technical Reports Server (NTRS)

Beering, David R.

2005-01-01

A gateway has been developed to enable digital communication between (1) the high-rate receiving equipment at NASA's White Sands complex and (2) a standard terrestrial digital communication network at data rates up to 622 Mb/s. The design of this gateway can also be adapted for use in commercial Earth/satellite and digital communication networks, and in terrestrial digital communication networks that include wireless subnetworks. Gateway as used here signifies an electronic circuit that serves as an interface between two electronic communication networks so that a computer (or other terminal) on one network can communicate with a terminal on the other network. The connection between this gateway and the high-rate receiving equipment is made via a synchronous serial data interface at the emitter-coupled-logic (ECL) level. The connection between this gateway and a standard asynchronous transfer mode (ATM) terrestrial communication network is made via a standard user network interface with a synchronous optical network (SONET) connector. The gateway contains circuitry that performs the conversion between the ECL and SONET interfaces. The data rate of the SONET interface can be either 155.52 or 622.08 Mb/s. The gateway derives its clock signal from a satellite modem in the high-rate receiving equipment and, hence, is agile in the sense that it adapts to the data rate of the serial interface.

Robust Networking Architecture and Secure Communication Scheme for Heterogeneous Wireless Sensor Networks

ERIC Educational Resources Information Center

McNeal, McKenzie, III.

2012-01-01

Current networking architectures and communication protocols used for Wireless Sensor Networks (WSNs) have been designed to be energy efficient, low latency, and long network lifetime. One major issue that must be addressed is the security in data communication. Due to the limited capabilities of low cost and small sized sensor nodes, designing…

Scalable Hierarchical Network Management System for Displaying Network Information in Three Dimensions

NASA Technical Reports Server (NTRS)

George, Jude (Inventor); Schlecht, Leslie (Inventor); McCabe, James D. (Inventor); LeKashman, John Jr. (Inventor)

1998-01-01

A network management system has SNMP agents distributed at one or more sites, an input output module at each site, and a server module located at a selected site for communicating with input output modules, each of which is configured for both SNMP and HNMP communications. The server module is configured exclusively for HNMP communications, and it communicates with each input output module according to the HNMP. Non-iconified, informationally complete views are provided of network elements to aid in network management.

Balancing energy consumption with hybrid clustering and routing strategy in wireless sensor networks.

PubMed

Xu, Zhezhuang; Chen, Liquan; Liu, Ting; Cao, Lianyang; Chen, Cailian

2015-10-20

Multi-hop data collection in wireless sensor networks (WSNs) is a challenge issue due to the limited energy resource and transmission range of wireless sensors. The hybrid clustering and routing (HCR) strategy has provided an effective solution, which can generate a connected and efficient cluster-based topology for multi-hop data collection in WSNs. However, it suffers from imbalanced energy consumption, which results in the poor performance of the network lifetime. In this paper, we evaluate the energy consumption of HCR and discover an important result: the imbalanced energy consumption generally appears in gradient k = 1, i.e., the nodes that can communicate with the sink directly. Based on this observation, we propose a new protocol called HCR-1, which includes the adaptive relay selection and tunable cost functions to balance the energy consumption. The guideline of setting the parameters in HCR-1 is provided based on simulations. The analytical and numerical results prove that, with minor modification of the topology in Sensors 2015, 15 26584 gradient k = 1, the HCR-1 protocol effectively balances the energy consumption and prolongs the network lifetime.

Explicit Content Caching at Mobile Edge Networks with Cross-Layer Sensing

PubMed Central

Chen, Lingyu; Su, Youxing; Luo, Wenbin; Hong, Xuemin; Shi, Jianghong

2018-01-01

The deployment density and computational power of small base stations (BSs) are expected to increase significantly in the next generation mobile communication networks. These BSs form the mobile edge network, which is a pervasive and distributed infrastructure that can empower a variety of edge/fog computing applications. This paper proposes a novel edge-computing application called explicit caching, which stores selective contents at BSs and exposes such contents to local users for interactive browsing and download. We formulate the explicit caching problem as a joint content recommendation, caching, and delivery problem, which aims to maximize the expected user quality-of-experience (QoE) with varying degrees of cross-layer sensing capability. Optimal and effective heuristic algorithms are presented to solve the problem. The theoretical performance bounds of the explicit caching system are derived in simplified scenarios. The impacts of cache storage space, BS backhaul capacity, cross-layer information, and user mobility on the system performance are simulated and discussed in realistic scenarios. Results suggest that, compared with conventional implicit caching schemes, explicit caching can better exploit the mobile edge network infrastructure for personalized content dissemination. PMID:29565313

Explicit Content Caching at Mobile Edge Networks with Cross-Layer Sensing.

PubMed

Chen, Lingyu; Su, Youxing; Luo, Wenbin; Hong, Xuemin; Shi, Jianghong

2018-03-22

The deployment density and computational power of small base stations (BSs) are expected to increase significantly in the next generation mobile communication networks. These BSs form the mobile edge network, which is a pervasive and distributed infrastructure that can empower a variety of edge/fog computing applications. This paper proposes a novel edge-computing application called explicit caching, which stores selective contents at BSs and exposes such contents to local users for interactive browsing and download. We formulate the explicit caching problem as a joint content recommendation, caching, and delivery problem, which aims to maximize the expected user quality-of-experience (QoE) with varying degrees of cross-layer sensing capability. Optimal and effective heuristic algorithms are presented to solve the problem. The theoretical performance bounds of the explicit caching system are derived in simplified scenarios. The impacts of cache storage space, BS backhaul capacity, cross-layer information, and user mobility on the system performance are simulated and discussed in realistic scenarios. Results suggest that, compared with conventional implicit caching schemes, explicit caching can better exploit the mobile edge network infrastructure for personalized content dissemination.

DNET: A communications facility for distributed heterogeneous computing

NASA Technical Reports Server (NTRS)

Tole, John; Nagappan, S.; Clayton, J.; Ruotolo, P.; Williamson, C.; Solow, H.

1989-01-01

This document describes DNET, a heterogeneous data communications networking facility. DNET allows programs operating on hosts on dissimilar networks to communicate with one another without concern for computer hardware, network protocol, or operating system differences. The overall DNET network is defined as the collection of host machines/networks on which the DNET software is operating. Each underlying network is considered a DNET 'domain'. Data communications service is provided between any two processes on any two hosts on any of the networks (domains) that may be reached via DNET. DNET provides protocol transparent, reliable, streaming data transmission between hosts (restricted, initially to DECnet and TCP/IP networks). DNET also provides variable length datagram service with optional return receipts.

Unified Approach to Modeling and Simulation of Space Communication Networks and Systems

NASA Technical Reports Server (NTRS)

Barritt, Brian; Bhasin, Kul; Eddy, Wesley; Matthews, Seth

2010-01-01

Network simulator software tools are often used to model the behaviors and interactions of applications, protocols, packets, and data links in terrestrial communication networks. Other software tools that model the physics, orbital dynamics, and RF characteristics of space systems have matured to allow for rapid, detailed analysis of space communication links. However, the absence of a unified toolset that integrates the two modeling approaches has encumbered the systems engineers tasked with the design, architecture, and analysis of complex space communication networks and systems. This paper presents the unified approach and describes the motivation, challenges, and our solution - the customization of the network simulator to integrate with astronautical analysis software tools for high-fidelity end-to-end simulation. Keywords space; communication; systems; networking; simulation; modeling; QualNet; STK; integration; space networks

Real-Time Communication Support for Underwater Acoustic Sensor Networks †.

PubMed

Santos, Rodrigo; Orozco, Javier; Micheletto, Matias; Ochoa, Sergio F; Meseguer, Roc; Millan, Pere; Molina, And Carlos

2017-07-14

Underwater sensor networks represent an important and promising field of research due to the large diversity of underwater ubiquitous applications that can be supported by these networks, e.g., systems that deliver tsunami and oil spill warnings, or monitor submarine ecosystems. Most of these monitoring and warning systems require real-time communication in wide area networks that have a low density of nodes. The underwater communication medium involved in these networks is very harsh and imposes strong restrictions to the communication process. In this scenario, the real-time transmission of information is done mainly using acoustic signals, since the network nodes are not physically close. The features of the communication scenario and the requirements of the communication process represent major challenges for designers of both, communication protocols and monitoring and warning systems. The lack of models to represent these networks is the main stumbling block for the proliferation of underwater ubiquitous systems. This paper presents a real-time communication model for underwater acoustic sensor networks (UW-ASN) that are designed to cover wide areas with a low density of nodes, using any-to-any communication. This model is analytic, considers two solution approaches for scheduling the real-time messages, and provides a time-constraint analysis for the network performance. Using this model, the designers of protocols and underwater ubiquitous systems can quickly prototype and evaluate their solutions in an evolving way, in order to determine the best solution to the problem being addressed. The suitability of the proposal is illustrated with a case study that shows the performance of a UW-ASN under several initial conditions. This is the first analytic model for representing real-time communication in this type of network, and therefore, it opens the door for the development of underwater ubiquitous systems for several application scenarios.

Real-Time Communication Support for Underwater Acoustic Sensor Networks †

PubMed Central

Santos, Rodrigo; Orozco, Javier; Micheletto, Matias

2017-01-01

Underwater sensor networks represent an important and promising field of research due to the large diversity of underwater ubiquitous applications that can be supported by these networks, e.g., systems that deliver tsunami and oil spill warnings, or monitor submarine ecosystems. Most of these monitoring and warning systems require real-time communication in wide area networks that have a low density of nodes. The underwater communication medium involved in these networks is very harsh and imposes strong restrictions to the communication process. In this scenario, the real-time transmission of information is done mainly using acoustic signals, since the network nodes are not physically close. The features of the communication scenario and the requirements of the communication process represent major challenges for designers of both, communication protocols and monitoring and warning systems. The lack of models to represent these networks is the main stumbling block for the proliferation of underwater ubiquitous systems. This paper presents a real-time communication model for underwater acoustic sensor networks (UW-ASN) that are designed to cover wide areas with a low density of nodes, using any-to-any communication. This model is analytic, considers two solution approaches for scheduling the real-time messages, and provides a time-constraint analysis for the network performance. Using this model, the designers of protocols and underwater ubiquitous systems can quickly prototype and evaluate their solutions in an evolving way, in order to determine the best solution to the problem being addressed. The suitability of the proposal is illustrated with a case study that shows the performance of a UW-ASN under several initial conditions. This is the first analytic model for representing real-time communication in this type of network, and therefore, it opens the door for the development of underwater ubiquitous systems for several application scenarios. PMID:28708093

Computer Networks as a New Data Base.

ERIC Educational Resources Information Center

Beals, Diane E.

1992-01-01

Discusses the use of communication on computer networks as a data source for psychological, social, and linguistic research. Differences between computer-mediated communication and face-to-face communication are described, the Beginning Teacher Computer Network is discussed, and examples of network conversations are appended. (28 references) (LRW)

Communication performance analysis and comparison of two patterns for data exchange between nodes in WorldFIP fieldbus network.

PubMed

Liang, Geng; Wang, Hong; Li, Wen; Li, Dazhong

2010-10-01

Data exchange patterns between nodes in WorldFIP fieldbus network are quite important and meaningful in improving the communication performance of WorldFIP network. Based on the basic communication ways supported in WorldFIP protocol, we propose two patterns for implementation of data exchange between peer nodes over WorldFIP network. Effects on communication performance of WorldFIP network in terms of some network parameters, such as number of bytes in user's data and turn-around time, in both the proposed patterns, are analyzed at length when different network speeds are applied. Such effects with the patterns of periodic message transmission using acknowledged and non-acknowledged messages, are also studied. Communication performance in both the proposed patterns are analyzed and compared. Practical applications of the research are presented. Through the study, it can be seen that different data exchange patterns make a great difference in improving communication efficiency with different network parameters, which is quite useful and helpful in the practical design of distributed systems based on WorldFIP network. Copyright © 2010 ISA. Published by Elsevier Ltd. All rights reserved.

46 CFR 113.30-3 - Means of communications.

Code of Federal Regulations, 2010 CFR

2010-10-01

... equipment; and (2) Provide common talking means of two-way voice communication and calling among the... positions listed in § 113.30-5. (b) The means of communication and calling must be a reliable means of voice... 46 Shipping 4 2010-10-01 2010-10-01 false Means of communications. 113.30-3 Section 113.30-3...

Temporal motifs reveal collaboration patterns in online task-oriented networks

NASA Astrophysics Data System (ADS)

Xuan, Qi; Fang, Huiting; Fu, Chenbo; Filkov, Vladimir

2015-05-01

Real networks feature layers of interactions and complexity. In them, different types of nodes can interact with each other via a variety of events. Examples of this complexity are task-oriented social networks (TOSNs), where teams of people share tasks towards creating a quality artifact, such as academic research papers or software development in commercial or open source environments. Accomplishing those tasks involves both work, e.g., writing the papers or code, and communication, to discuss and coordinate. Taking into account the different types of activities and how they alternate over time can result in much more precise understanding of the TOSNs behaviors and outcomes. That calls for modeling techniques that can accommodate both node and link heterogeneity as well as temporal change. In this paper, we report on methodology for finding temporal motifs in TOSNs, limited to a system of two people and an artifact. We apply the methods to publicly available data of TOSNs from 31 Open Source Software projects. We find that these temporal motifs are enriched in the observed data. When applied to software development outcome, temporal motifs reveal a distinct dependency between collaboration and communication in the code writing process. Moreover, we show that models based on temporal motifs can be used to more precisely relate both individual developer centrality and team cohesion to programmer productivity than models based on aggregated TOSNs.

Temporal motifs reveal collaboration patterns in online task-oriented networks.

PubMed

Xuan, Qi; Fang, Huiting; Fu, Chenbo; Filkov, Vladimir

2015-05-01

Real networks feature layers of interactions and complexity. In them, different types of nodes can interact with each other via a variety of events. Examples of this complexity are task-oriented social networks (TOSNs), where teams of people share tasks towards creating a quality artifact, such as academic research papers or software development in commercial or open source environments. Accomplishing those tasks involves both work, e.g., writing the papers or code, and communication, to discuss and coordinate. Taking into account the different types of activities and how they alternate over time can result in much more precise understanding of the TOSNs behaviors and outcomes. That calls for modeling techniques that can accommodate both node and link heterogeneity as well as temporal change. In this paper, we report on methodology for finding temporal motifs in TOSNs, limited to a system of two people and an artifact. We apply the methods to publicly available data of TOSNs from 31 Open Source Software projects. We find that these temporal motifs are enriched in the observed data. When applied to software development outcome, temporal motifs reveal a distinct dependency between collaboration and communication in the code writing process. Moreover, we show that models based on temporal motifs can be used to more precisely relate both individual developer centrality and team cohesion to programmer productivity than models based on aggregated TOSNs.

SDN-based path hopping communication against eavesdropping attack

NASA Astrophysics Data System (ADS)

Zhang, Chuanhao; Bu, Youjun; Zhao, Zheng

2016-10-01

Network eavesdropping is one of the most popular means used by cyber attackers, which has been a severe threat to network communication security. Adversaries could capture and analyze network communication data from network nodes or links, monitor network status and steal sensitive data such as username and password etc. Traditional network usually uses static network configuration, and existing defense methods, including firewall, IDS, IPS etc., cannot prevent eavesdropping, which has no distinguishing characteristic. Network eavesdropping become silent during most of the time of the attacking process, which is why it is difficult to discover and to defend. But A successful eavesdropping attack also has its' precondition, which is the target path should be relatively stable and has enough time of duration. So, In order to resolve this problem, it has to work on the network architecture. In this paper, a path hopping communication(PHC) mechanism based on Software Define Network (SDN) was proposed to solve this problem. In PHC, Ends in communication packets as well as the routing paths were changed dynamically. Therefore, the traffic would be distributed to multiple flows and transmitted along different paths. so that Network eavesdropping attack could be prevented effectively. It was concluded that PHC was able to increase the overhead of Network eavesdropping, as well as the difficulty of communication data recovery.

Assessing communication skills of clinical call handlers working at an out-of-hours centre: development of the RICE rating scale.

PubMed

Derkx, Hay P; Rethans, Jan-Joost E; Knottnerus, J André; Ram, Paul M

2007-05-01

Out-of-hours centres provide telephone support to patients with medical problems. In most of these centres specially-trained nurses handle incoming telephone calls. They assess patients' needs, the degree of urgency, and determine the level of care required. Assessment of the medical problem and the quality of 'care-by-phone' depend on the medical and communication skills of the call handlers. To develop a valid, reliable, and practical rating scale to evaluate the communication skills of call handlers working at an out-of-hours centre and to improve quality of communication. Qualitative study with focus groups followed by validation of the rating scale and measurement of reliability (internal consistency). Out-of-hours centres in the Netherlands. A focus group developed the rating scale. Experts with experience in training and evaluating communication skills of medical students and GPs commented on the scale to ensure content validity. The reliability of the rating scale was tested in a pilot in which ten specially-trained assessors scored six telephone calls each. The scale, known as the RICE rating scale, has 17 items divided over four different phases of the telephone consultation: Reason for calling; Information gathering; Conclusion; and Evaluation (RICE). Content validity of the scale was assessed by two experts. Reliability of the scale tested in the pilot was 0.73 (Cronbach's alpha). Establishing a rating scale to assess the communication skills of call handlers which meets common scientific demands, such as content validity and reliability, proved successful. This instrument can be used to give feedback to call handlers.

Quantum network with trusted and untrusted relays

NASA Astrophysics Data System (ADS)

Ma, Xiongfeng; Annabestani, Razieh; Fung, Chi-Hang Fred; Lo, Hoi-Kwong; Lütkenhaus, Norbert; PitkäNen, David; Razavi, Mohsen

2012-02-01

Quantum key distribution offers two distant users to establish a random secure key by exploiting properties of quantum mechanics, whose security has proven in theory. In practice, many lab and field demonstrations have been performed in the last 20 years. Nowadays, quantum network with quantum key distribution systems are tested around the world, such as in China, Europe, Japan and US. In this talk, I will give a brief introduction of recent development for quantum network. For the untrusted relay part, I will introduce the measurement-device-independent quantum key distribution scheme and a quantum relay with linear optics. The security of such scheme is proven without assumptions on the detection devices, where most of quantum hacking strategies are launched. This scheme can be realized with current technology. For the trusted relay part, I will introduce so-called delayed privacy amplification, with which no error correction and privacy amplification is necessarily to be performed between users and the relay. In this way, classical communications and computational power requirement on the relay site will be reduced.

Ecological systems as computer networks: Long distance sea dispersal as a communication medium between island plant populations.

PubMed

Sanaa, Adnen; Ben Abid, Samir; Boulila, Abdennacer; Messaoud, Chokri; Boussaid, Mohamed; Ben Fadhel, Najeh

2016-06-01

Ecological systems are known to exchange genetic material through animal species migration and seed dispersal for plants. Isolated plant populations have developed long distance dispersal as a means of propagation which rely on meteorological such as anemochory and hydrochory for coast, island and river bank dwelling species. Long distance dispersal by water, in particular, in the case of water current bound islands, calls for the analogy with computer networks, where each island and nearby mainland site plays the role of a network node, the water currents play the role of a transmission channel, and water borne seeds as data packets. In this paper we explore this analogy to model long distance dispersal of seeds among island and mainland populations, when traversed with water currents, in order to model and predict their future genetic diversity. The case of Pancratium maritimum L. populations in Tunisia is used as a proof of concept, where their genetic diversity is extrapolated. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

Bridging the Communication Gap: Successes and Challenges of Mobile Phone Technology in a Health and Demographic Surveillance System in Northern Nigeria

PubMed Central

Doctor, Henry V.; Olatunji, Alabi; Jumare, Abdul’Azeez

2012-01-01

Maternal and child health indicators are generally poor in Nigeria with the northern part of the country having the worst indicators than the southern part. Efforts to address maternal and health challenges in Nigeria include, among others, improvement in health and management information systems. We report on the experience of mobile phone technology in supporting the activities of a health and demographic surveillance system in northern Nigeria. Our experience calls for the need for the Nigerian Government, the mobile network companies, and the international community at large to consolidate their efforts in addressing the mobile network coverage and power supply challenges in order to create an enabling environment for socio-economic development particularly in rural and disadvantaged areas. Unless power and mobile network challenges are addressed, health interventions that rely on mobile phone technology will not have a significant impact in improving maternal and child health. PMID:23569650

A study of anthropogenic and climatic disturbance of the New River Estuary using a Bayesian belief network.

PubMed

Nojavan A, Farnaz; Qian, Song S; Paerl, Hans W; Reckhow, Kenneth H; Albright, Elizabeth A

2014-06-15

The present paper utilizes a Bayesian Belief Network (BBN) approach to intuitively present and quantify our current understanding of the complex physical, chemical, and biological processes that lead to eutrophication in an estuarine ecosystem (New River Estuary, North Carolina, USA). The model is further used to explore the effects of plausible future climatic and nutrient pollution management scenarios on water quality indicators. The BBN, through visualizing the structure of the network, facilitates knowledge communication with managers/stakeholders who might not be experts in the underlying scientific disciplines. Moreover, the developed structure of the BBN is transferable to other comparable estuaries. The BBN nodes are discretized exploring a new approach called moment matching method. The conditional probability tables of the variables are driven by a large dataset (four years). Our results show interaction among various predictors and their impact on water quality indicators. The synergistic effects caution future management actions. Copyright © 2014 Elsevier Ltd. All rights reserved.

A Pub/Sub Message Distribution Architecture for Disruption Tolerant Networks

NASA Astrophysics Data System (ADS)

Carrilho, Sergio; Esaki, Hiroshi

Access to information is taken for granted in urban areas covered by a robust communication infrastructure. Nevertheless most of the areas in the world, are not covered by such infrastructures. We propose a DTN publish and subscribe system called Hikari, which uses nodes' mobility in order to distribute messages without using a robust infrastructure. The area of Disruption/Delay Tolerant Networks (DTN) focuses on providing connectivity to locations separated by networks with disruptions and delays. The Hikari system does not use node identifiers for message forwarding thus eliminating the complexity of routing associated with many forwarding schemes in DTN. Hikari uses nodes paths' information, advertised by special nodes in the system or predicted by the system itself, for optimizing the message dissemination process. We have used the Paris subway system, due to it's complexity, to validate Hikari and to analyze it's performance. We have shown that Hikari achieves a superior deliver rate while keeping redundant messages in the system low, which is ideal when using devices with limited resources for message dissemination.

Mixture block coding with progressive transmission in packet video. Appendix 1: Item 2. M.S. Thesis

NASA Technical Reports Server (NTRS)

Chen, Yun-Chung

1989-01-01

Video transmission will become an important part of future multimedia communication because of dramatically increasing user demand for video, and rapid evolution of coding algorithm and VLSI technology. Video transmission will be part of the broadband-integrated services digital network (B-ISDN). Asynchronous transfer mode (ATM) is a viable candidate for implementation of B-ISDN due to its inherent flexibility, service independency, and high performance. According to the characteristics of ATM, the information has to be coded into discrete cells which travel independently in the packet switching network. A practical realization of an ATM video codec called Mixture Block Coding with Progressive Transmission (MBCPT) is presented. This variable bit rate coding algorithm shows how a constant quality performance can be obtained according to user demand. Interactions between codec and network are emphasized including packetization, service synchronization, flow control, and error recovery. Finally, some simulation results based on MBCPT coding with error recovery are presented.

Toward domain-specific design environments: Some representation ideas from the telecommunications domain

NASA Technical Reports Server (NTRS)

Greenspan, Sol; Feblowitz, Mark

1992-01-01

ACME is an experimental environment for investigating new approaches to modeling and analysis of system requirements and designs. ACME is built on and extends object-oriented conceptual modeling techniques and knowledge representation and reasoning (KRR) tools. The most immediate intended use for ACME is to help represent, understand, and communicate system designs during the early stages of system planning and requirements engineering. While our research is ostensibly aimed at software systems in general, we are particularly motivated to make an impact in the telecommunications domain, especially in the area referred to as Intelligent Networks (IN's). IN systems contain the software to provide services to users of a telecommunications network (e.g., call processing services, information services, etc.) as well as the software that provides the internal infrastructure for providing the services (e.g., resource management, billing, etc.). The software includes not only systems developed by the network proprietors but also by a growing group of independent service software providers.

On the Relevancy of Efficient, Integrated Computer and Network Monitoring in HEP Distributed Online Environment

NASA Astrophysics Data System (ADS)

Carvalho, D.; Gavillet, Ph.; Delgado, V.; Albert, J. N.; Bellas, N.; Javello, J.; Miere, Y.; Ruffinoni, D.; Smith, G.

Large Scientific Equipments are controlled by Computer Systems whose complexity is growing driven, on the one hand by the volume and variety of the information, its distributed nature, the sophistication of its treatment and, on the other hand by the fast evolution of the computer and network market. Some people call them genetically Large-Scale Distributed Data Intensive Information Systems or Distributed Computer Control Systems (DCCS) for those systems dealing more with real time control. Taking advantage of (or forced by) the distributed architecture, the tasks are more and more often implemented as Client-Server applications. In this framework the monitoring of the computer nodes, the communications network and the applications becomes of primary importance for ensuring the safe running and guaranteed performance of the system. With the future generation of HEP experiments, such as those at the LHC in view, it is proposed to integrate the various functions of DCCS monitoring into one general purpose Multi-layer System.

Medicine in the Internet age. The rise of the network society.

PubMed

Rossi, Paolo

2006-01-01

When social scientists began analyzing the socio-cultural impact of the Internet, health emerged as one of the areas in which the Internet has become a key means of communication and cultural expression. It is no exaggeration to say that the Internet is bringing about a structural transformation of the cultural practices and organization of health systems. This is the so-called online revolution of health systems. The Internet has both the usership and the technical prerequisites to be an ideal medium for promoting health-related education and support, but what makes the Internet the health medium par excellence is the fact that it is the mode of cultural expression and output most compatible with the transformations that have taken place and are taking place in our society: that is, with the rise of the network society. In this paper, I discuss the opportunities and challenges arising from the transformation of health systems into patient-centred networks.

Co-clustering directed graphs to discover asymmetries and directional communities

PubMed Central

Rohe, Karl; Qin, Tai; Yu, Bin

2016-01-01

In directed graphs, relationships are asymmetric and these asymmetries contain essential structural information about the graph. Directed relationships lead to a new type of clustering that is not feasible in undirected graphs. We propose a spectral co-clustering algorithm called di-sim for asymmetry discovery and directional clustering. A Stochastic co-Blockmodel is introduced to show favorable properties of di-sim. To account for the sparse and highly heterogeneous nature of directed networks, di-sim uses the regularized graph Laplacian and projects the rows of the eigenvector matrix onto the sphere. A nodewise asymmetry score and di-sim are used to analyze the clustering asymmetries in the networks of Enron emails, political blogs, and the Caenorhabditis elegans chemical connectome. In each example, a subset of nodes have clustering asymmetries; these nodes send edges to one cluster, but receive edges from another cluster. Such nodes yield insightful information (e.g., communication bottlenecks) about directed networks, but are missed if the analysis ignores edge direction. PMID:27791058

Co-clustering directed graphs to discover asymmetries and directional communities.

PubMed

Rohe, Karl; Qin, Tai; Yu, Bin

2016-10-21

In directed graphs, relationships are asymmetric and these asymmetries contain essential structural information about the graph. Directed relationships lead to a new type of clustering that is not feasible in undirected graphs. We propose a spectral co-clustering algorithm called di-sim for asymmetry discovery and directional clustering. A Stochastic co-Blockmodel is introduced to show favorable properties of di-sim To account for the sparse and highly heterogeneous nature of directed networks, di-sim uses the regularized graph Laplacian and projects the rows of the eigenvector matrix onto the sphere. A nodewise asymmetry score and di-sim are used to analyze the clustering asymmetries in the networks of Enron emails, political blogs, and the Caenorhabditis elegans chemical connectome. In each example, a subset of nodes have clustering asymmetries; these nodes send edges to one cluster, but receive edges from another cluster. Such nodes yield insightful information (e.g., communication bottlenecks) about directed networks, but are missed if the analysis ignores edge direction.

Future Data Communication Architectures for Safety Critical Aircraft Cabin Systems

NASA Astrophysics Data System (ADS)

Berkhahn, Sven-Olaf

2012-05-01

The cabin of modern aircraft is subject to increasing demands for fast reconfiguration and hence flexibility. These demands require studies for new network architectures and technologies of the electronic cabin systems, which consider also weight and cost reductions as well as safety constraints. Two major approaches are in consideration to reduce the complex and heavy wiring harness: the usage of a so called hybrid data bus technology, which enables the common usage of the same data bus for several electronic cabin systems with different safety and security requirements and the application of wireless data transfer technologies for electronic cabin systems.

78 FR 55096 - Certain Point-to-Point Network Communication Devices and Products Containing Same; Institution of...

Federal Register 2010, 2011, 2012, 2013, 2014

2013-09-09

... INTERNATIONAL TRADE COMMISSION [Investigation No. 337-TA-892] Certain Point-to-Point Network... sale within the United States after importation of certain point-to- point network communication... sale within the United States after importation of certain point-to- point network communication...

Improving the reliability of verbal communication between primary care physicians and pediatric hospitalists at hospital discharge.

PubMed

Mussman, Grant M; Vossmeyer, Michael T; Brady, Patrick W; Warrick, Denise M; Simmons, Jeffrey M; White, Christine M

2015-09-01

Timely and reliable verbal communication between hospitalists and primary care physicians (PCPs) is critical for prevention of medical adverse events but difficult in practice. Our aim was to increase the proportion of completed verbal handoffs from on-call residents or attendings to PCPs within 24 hours of patient discharge from a hospital medicine service to ≥90% within 18 months. A multidisciplinary team collaborated to redesign the process by which PCPs were contacted following patient discharge. Interventions focused on the key drivers of obtaining stakeholder buy-in, standardization of the communication process, including assigning primary responsibility for discharge communication to a single resident on each team and batching calls during times of maximum resident availability, reliable automated process initiation through leveraging the electronic health record (EHR), and transparency of data. A run chart assessed the impact of interventions over time. The percentage of calls initiated within 24 hours of discharge improved from 52% to 97%, and the percentage of calls completed improved to 93%. Results were sustained for 18 months. Standardization of the communication process through hospital telephone operators, use of the discharge order to ensure initiation of discharge communication, and batching of phone calls were associated with improvements in our measures. Reliable verbal discharge communication can be achieved through the use of a standardized discharge communication process coupled with the EHR. © 2015 Society of Hospital Medicine.

Cooperative UAV-Based Communications Backbone for Sensor Networks

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

Roberts, R S

2001-10-07

The objective of this project is to investigate the use of unmanned air vehicles (UAVs) as mobile, adaptive communications backbones for ground-based sensor networks. In this type of network, the UAVs provide communication connectivity to sensors that cannot communicate with each other because of terrain, distance, or other geographical constraints. In these situations, UAVs provide a vertical communication path for the sensors, thereby mitigating geographic obstacles often imposed on networks. With the proper use of UAVs, connectivity to a widely disbursed sensor network in rugged terrain is readily achieved. Our investigation has focused on networks where multiple cooperating UAVs aremore » used to form a network backbone. The advantage of using multiple UAVs to form the network backbone is parallelization of sensor connectivity. Many widely spaced or isolated sensors can be connected to the network at once using this approach. In these networks, the UAVs logically partition the sensor network into sub-networks (subnets), with one UAV assigned per subnet. Partitioning the network into subnets allows the UAVs to service sensors in parallel thereby decreasing the sensor-to-network connectivity. A UAV services sensors in its subnet by flying a route (path) through the subnet, uplinking data collected by the sensors, and forwarding the data to a ground station. An additional advantage of using multiple UAVs in the network is that they provide redundancy in the communications backbone, so that the failure of a single UAV does not necessarily imply the loss of the network.« less

The fragmented self: imbalance between intrinsic and extrinsic self-networks in psychotic disorders.

PubMed

Ebisch, Sjoerd J H; Aleman, André

2016-08-01

Self-disturbances are among the core features of schizophrenia and related psychotic disorders. The basic structure of the self could depend on the balance between intrinsic and extrinsic self-processing. We discuss studies on self-related processing in psychotic disorders that provide converging evidence for disrupted communication between neural networks subserving the so-called intrinsic self and extrinsic self. This disruption might be mainly caused by impaired integrity of key brain hubs. The intrinsic self has been associated with cortical midline structures involved in self-referential processing, autobiographical memory, and emotional evaluation. Additionally, we highlight central aspects of the extrinsic self in its interaction with the environment using sensorimotor networks, including self-experience in sensation and actions. A deficient relationship between these self-aspects because of disrupted between-network interactions offers a framework to explain core clinical features of psychotic disorders. In particular, we show how relative isolation and reduced modularity of networks subserving intrinsic and extrinsic self-processing might trigger the emergence of hallucinations and delusions, and why patients with psychosis typically have difficulties with self-other relationships and do not recognise mental problems. Copyright © 2016 Elsevier Ltd. All rights reserved.

An information theory account of cognitive control

PubMed Central

Fan, Jin

2014-01-01

Our ability to efficiently process information and generate appropriate responses depends on the processes collectively called cognitive control. Despite a considerable focus in the literature on the cognitive control of information processing, neural mechanisms underlying control are still unclear, and have not been characterized by considering the quantity of information to be processed. A novel and comprehensive account of cognitive control is proposed using concepts from information theory, which is concerned with communication system analysis and the quantification of information. This account treats the brain as an information-processing entity where cognitive control and its underlying brain networks play a pivotal role in dealing with conditions of uncertainty. This hypothesis and theory article justifies the validity and properties of such an account and relates experimental findings to the frontoparietal network under the framework of information theory. PMID:25228875

Internet and World Wide Web-based tools for neuropathology practice and education.

PubMed

Fung, Kar-Ming; Tihan, Tarik

2009-04-01

The Internet and the World Wide Web (www) serve as a source of information and a communication network. Together they form a so-called web or network that allows for transmission and dissemination of information in unprecedented speed, volume and detail. This article presents an overview of the current status of neuropathology content on the www. As well as considering the Internet as a resource for neuropathology practice, education and research, we also address the issue of quality assurance when evaluating Internet and www content. Four major categories of websites (archival, broker, news and blog) are discussed and resources relevant to neuropathology of each type are highlighted. We believe that our report and similar attempts can provide an opportunity to discuss appropriate and effective use of the Internet by the neuropathology community.

Adaptive feedback synchronisation of complex dynamical network with discrete-time communications and delayed nodes

NASA Astrophysics Data System (ADS)

Wang, Tong; Ding, Yongsheng; Zhang, Lei; Hao, Kuangrong

2016-08-01

This paper considered the synchronisation of continuous complex dynamical networks with discrete-time communications and delayed nodes. The nodes in the dynamical networks act in the continuous manner, while the communications between nodes are discrete-time; that is, they communicate with others only at discrete time instants. The communication intervals in communication period can be uncertain and variable. By using a piecewise Lyapunov-Krasovskii function to govern the characteristics of the discrete communication instants, we investigate the adaptive feedback synchronisation and a criterion is derived to guarantee the existence of the desired controllers. The globally exponential synchronisation can be achieved by the controllers under the updating laws. Finally, two numerical examples including globally coupled network and nearest-neighbour coupled networks are presented to demonstrate the validity and effectiveness of the proposed control scheme.

Vocalizations of eight species of Atelopus (Anura: Bufonidae) with comments on communication in the genus

USGS Publications Warehouse

Cocroft, R.B.; McDiarmid, R.W.; Jaslow, A.P.; Ruiz-Carranza, P.M.

1990-01-01

Vocalizations of frogs of the genus Atelopus include three discrete types of signals: pulsed calls, pure tone calls, and short calls. Repertoire composition is conservative across species. Repertoires of most species whose calls have been recorded contain two or three of these identifiable call types. Within a call type, details of call structure are very similar across species. This apparent lack of divergence in calls may be related to the rarity of sympatry among species of Atelopus and to the relative importance of visual communication in their social interactions.

User Needs and Advances in Space Wireless Sensing and Communications

NASA Technical Reports Server (NTRS)

Kegege, Obadiah

2017-01-01

Decades of space exploration and technology trends for future missions show the need for new approaches in space/planetary sensor networks, observatories, internetworking, and communications/data delivery to Earth. The User Needs to be discussed in this talk includes interviews with several scientists and reviews of mission concepts for the next generation of sensors, observatories, and planetary surface missions. These observatories, sensors are envisioned to operate in extreme environments, with advanced autonomy, whereby sometimes communication to Earth is intermittent and delayed. These sensor nodes require software defined networking capabilities in order to learn and adapt to the environment, collect science data, internetwork, and communicate. Also, some user cases require the level of intelligence to manage network functions (either as a host), mobility, security, and interface data to the physical radio/optical layer. For instance, on a planetary surface, autonomous sensor nodes would create their own ad-hoc network, with some nodes handling communication capabilities between the wireless sensor networks and orbiting relay satellites. A section of this talk will cover the advances in space communication and internetworking to support future space missions. NASA's Space Communications and Navigation (SCaN) program continues to evolve with the development of optical communication, a new vision of the integrated network architecture with more capabilities, and the adoption of CCSDS space internetworking protocols. Advances in wireless communications hardware and electronics have enabled software defined networking (DVB-S2, VCM, ACM, DTN, Ad hoc, etc.) protocols for improved wireless communication and network management. Developing technologies to fulfil these user needs for wireless communications and adoption of standardized communication/internetworking protocols will be a huge benefit to future planetary missions, space observatories, and manned missions to other planets.

78 FR 78809 - Rates for Interstate Inmate Calling Services

Federal Register 2010, 2011, 2012, 2013, 2014

2013-12-27

... FEDERAL COMMUNICATIONS COMMISSION 47 CFR Part 64 [WC Docket No. 12-375; DA 13-2379] Rates for Interstate Inmate Calling Services AGENCY: Federal Communications Commission. ACTION: Proposed rule... Communications Commission's Web site: http://fjallfoss.fcc.gov/ecfs2/ . Follow the instructions for submitting...

Neural dynamics of speech act comprehension: an MEG study of naming and requesting.

PubMed

Egorova, Natalia; Pulvermüller, Friedemann; Shtyrov, Yury

2014-05-01

The neurobiological basis and temporal dynamics of communicative language processing pose important yet unresolved questions. It has previously been suggested that comprehension of the communicative function of an utterance, i.e. the so-called speech act, is supported by an ensemble of neural networks, comprising lexico-semantic, action and mirror neuron as well as theory of mind circuits, all activated in concert. It has also been demonstrated that recognition of the speech act type occurs extremely rapidly. These findings however, were obtained in experiments with insufficient spatio-temporal resolution, thus possibly concealing important facets of the neural dynamics of the speech act comprehension process. Here, we used magnetoencephalography to investigate the comprehension of Naming and Request actions performed with utterances controlled for physical features, psycholinguistic properties and the probability of occurrence in variable contexts. The results show that different communicative actions are underpinned by a dynamic neural network, which differentiates between speech act types very early after the speech act onset. Within 50-90 ms, Requests engaged mirror-neuron action-comprehension systems in sensorimotor cortex, possibly for processing action knowledge and intentions. Still, within the first 200 ms of stimulus onset (100-150 ms), Naming activated brain areas involved in referential semantic retrieval. Subsequently (200-300 ms), theory of mind and mentalising circuits were activated in medial prefrontal and temporo-parietal areas, possibly indexing processing of intentions and assumptions of both communication partners. This cascade of stages of processing information about actions and intentions, referential semantics, and theory of mind may underlie dynamic and interactive speech act comprehension.

Wireless local area networking for linking a PC reporting system and PACS: clinical feasibility in emergency reporting.

PubMed

Yoshihiro, Akiko; Nakata, Norio; Harada, Junta; Tada, Shimpei

2002-01-01

Although local area networks (LANs) are commonplace in hospital-based radiology departments today, wireless LANs are still relatively unknown and untried. A linked wireless reporting system was developed to improve work throughput and efficiency. It allows radiologists, physicians, and technologists to review current radiology reports and images and instantly compare them with reports and images from previous examinations. This reporting system also facilitates creation of teaching files quickly, easily, and accurately. It consists of a Digital Imaging and Communications in Medicine 3.0-based picture archiving and communication system (PACS), a diagnostic report server, and portable laptop computers. The PACS interfaces with magnetic resonance imagers, computed tomographic scanners, and computed radiography equipment. The same kind of functionality is achievable with a wireless LAN as with a wired LAN, with comparable bandwidth but with less cabling infrastructure required. This wireless system is presently incorporated into the operations of the emergency and radiology departments, with future plans calling for applications in operating rooms, outpatient departments, all hospital wards, and intensive care units. No major problems have been encountered with the system, which is in constant use and appears to be quite successful. Copyright RSNA, 2002

Characterization of robotics parallel algorithms and mapping onto a reconfigurable SIMD machine

NASA Technical Reports Server (NTRS)

Lee, C. S. G.; Lin, C. T.

1989-01-01

The kinematics, dynamics, Jacobian, and their corresponding inverse computations are six essential problems in the control of robot manipulators. Efficient parallel algorithms for these computations are discussed and analyzed. Their characteristics are identified and a scheme on the mapping of these algorithms to a reconfigurable parallel architecture is presented. Based on the characteristics including type of parallelism, degree of parallelism, uniformity of the operations, fundamental operations, data dependencies, and communication requirement, it is shown that most of the algorithms for robotic computations possess highly regular properties and some common structures, especially the linear recursive structure. Moreover, they are well-suited to be implemented on a single-instruction-stream multiple-data-stream (SIMD) computer with reconfigurable interconnection network. The model of a reconfigurable dual network SIMD machine with internal direct feedback is introduced. A systematic procedure internal direct feedback is introduced. A systematic procedure to map these computations to the proposed machine is presented. A new scheduling problem for SIMD machines is investigated and a heuristic algorithm, called neighborhood scheduling, that reorders the processing sequence of subtasks to reduce the communication time is described. Mapping results of a benchmark algorithm are illustrated and discussed.

Shared developmental and evolutionary origins for neural basis of vocal–acoustic and pectoral–gestural signaling

PubMed Central

Bass, Andrew H.; Chagnaud, Boris P.

2012-01-01

Acoustic signaling behaviors are widespread among bony vertebrates, which include the majority of living fishes and tetrapods. Developmental studies in sound-producing fishes and tetrapods indicate that central pattern generating networks dedicated to vocalization originate from the same caudal hindbrain rhombomere (rh) 8-spinal compartment. Together, the evidence suggests that vocalization and its morphophysiological basis, including mechanisms of vocal–respiratory coupling that are widespread among tetrapods, are ancestral characters for bony vertebrates. Premotor-motor circuitry for pectoral appendages that function in locomotion and acoustic signaling develops in the same rh8-spinal compartment. Hence, vocal and pectoral phenotypes in fishes share both developmental origins and roles in acoustic communication. These findings lead to the proposal that the coupling of more highly derived vocal and pectoral mechanisms among tetrapods, including those adapted for nonvocal acoustic and gestural signaling, originated in fishes. Comparative studies further show that rh8 premotor populations have distinct neurophysiological properties coding for equally distinct behavioral attributes such as call duration. We conclude that neural network innovations in the spatiotemporal patterning of vocal and pectoral mechanisms of social communication, including forelimb gestural signaling, have their evolutionary origins in the caudal hindbrain of fishes. PMID:22723366

Technology forecasting for space communication. [analysis of systems for application to Spacecraft Data and Tracking Network

NASA Technical Reports Server (NTRS)

1973-01-01

A study was conducted to determine techniques for application to space communication. The subjects considered are as follows: (1) optical communication systems, (2) laser communications for data acquisition networks, (3) spacecraft data rate requirements, (4) telemetry, command, and data handling, (5) spacecraft tracking and data network antenna and preamplifier cost tradeoff study, and (6) spacecraft communication terminal evaluation.

A cross-domain communication resource scheduling method for grid-enabled communication networks

NASA Astrophysics Data System (ADS)

Zheng, Xiangquan; Wen, Xiang; Zhang, Yongding

2011-10-01

To support a wide range of different grid applications in environments where various heterogeneous communication networks coexist, it is important to enable advanced capabilities in on-demand and dynamical integration and efficient co-share with cross-domain heterogeneous communication resource, thus providing communication services which are impossible for single communication resource to afford. Based on plug-and-play co-share and soft integration with communication resource, Grid-enabled communication network is flexibly built up to provide on-demand communication services for gird applications with various requirements on quality of service. Based on the analysis of joint job and communication resource scheduling in grid-enabled communication networks (GECN), this paper presents a cross multi-domain communication resource cooperatively scheduling method and describes the main processes such as traffic requirement resolution for communication services, cross multi-domain negotiation on communication resource, on-demand communication resource scheduling, and so on. The presented method is to afford communication service capability to cross-domain traffic delivery in GECNs. Further research work towards validation and implement of the presented method is pointed out at last.

A vision of network-centric military communications

NASA Astrophysics Data System (ADS)

Conklin, Ross, Jr.; Burbank, Jack; Nichols, Robert, Jr.

2005-05-01

This paper presents a vision for a future capability-based military communications system that considers user requirements. Historically, the military has developed and fielded many specialized communications systems. While these systems solved immediate communications problems, they were not designed to operate with other systems. As information has become more important to the execution of war, the "stove-pipe" nature of the communications systems deployed by the military is no longer acceptable. Realizing this, the military has begun the transformation of communications to a network-centric communications paradigm. However, the specialized communications systems were developed in response to the widely varying environments related to military communications. These environments, and the necessity for effective communications within these environments, do not disappear under the network-centric paradigm. In fact, network-centric communications allows for one message to cross many of these environments by transiting multiple networks. The military would also like one communications approach that is capable of working well in multiple environments. This paper presents preliminary work on the creation of a framework that allows for a reconfigurable device that is capable of adapting to the physical and network environments. The framework returns to the Open Systems Interconnect (OSI) architecture with the addition of a standardized intra-layer control interface for control information exchange, a standardized data interface and a proposed device architecture based on the software radio.

A new way to improve the robustness of complex communication networks by allocating redundancy links

NASA Astrophysics Data System (ADS)

Shi, Chunhui; Peng, Yunfeng; Zhuo, Yue; Tang, Jieying; Long, Keping

2012-03-01

We investigate the robustness of complex communication networks on allocating redundancy links. The protecting key nodes (PKN) strategy is proposed to improve the robustness of complex communication networks against intentional attack. Our numerical simulations show that allocating a few redundant links among key nodes using the PKN strategy will significantly increase the robustness of scale-free complex networks. We have also theoretically proved and demonstrated the effectiveness of the PKN strategy. We expect that our work will help achieve a better understanding of communication networks.

Phase transitions in distributed control systems with multiplicative noise

NASA Astrophysics Data System (ADS)

Allegra, Nicolas; Bamieh, Bassam; Mitra, Partha; Sire, Clément

2018-01-01

Contemporary technological challenges often involve many degrees of freedom in a distributed or networked setting. Three aspects are notable: the variables are usually associated with the nodes of a graph with limited communication resources, hindering centralized control; the communication is subject to noise; and the number of variables can be very large. These three aspects make tools and techniques from statistical physics particularly suitable for the performance analysis of such networked systems in the limit of many variables (analogous to the thermodynamic limit in statistical physics). Perhaps not surprisingly, phase-transition like phenomena appear in these systems, where a sharp change in performance can be observed with a smooth parameter variation, with the change becoming discontinuous or singular in the limit of infinite system size. In this paper, we analyze the so called network consensus problem, prototypical of the above considerations, that has previously been analyzed mostly in the context of additive noise. We show that qualitatively new phase-transition like phenomena appear for this problem in the presence of multiplicative noise. Depending on dimensions, and on the presence or absence of a conservation law, the system performance shows a discontinuous change at a threshold value of the multiplicative noise strength. In the absence of the conservation law, and for graph spectral dimension less than two, the multiplicative noise threshold (the stability margin of the control problem) is zero. This is reminiscent of the absence of robust controllers for certain classes of centralized control problems. Although our study involves a ‘toy’ model, we believe that the qualitative features are generic, with implications for the robust stability of distributed control systems, as well as the effect of roundoff errors and communication noise on distributed algorithms.

Secure, Mobile, Wireless Network Technology Designed, Developed, and Demonstrated

NASA Technical Reports Server (NTRS)

Ivancic, William D.; Paulsen, Phillip E.

2004-01-01

The inability to seamlessly disseminate data securely over a high-integrity, wireless broadband network has been identified as a primary technical barrier to providing an order-of-magnitude increase in aviation capacity and safety. Secure, autonomous communications to and from aircraft will enable advanced, automated, data-intensive air traffic management concepts, increase National Air Space (NAS) capacity, and potentially reduce the overall cost of air travel operations. For the first time ever, secure, mobile, network technology was designed, developed, and demonstrated with state-ofthe- art protocols and applications by a diverse, cooperative Government-industry team led by the NASA Glenn Research Center. This revolutionary technology solution will make fundamentally new airplane system capabilities possible by enabling secure, seamless network connections from platforms in motion (e.g., cars, ships, aircraft, and satellites) to existing terrestrial systems without the need for manual reconfiguration. Called Mobile Router, the new technology autonomously connects and configures networks as they traverse from one operating theater to another. The Mobile Router demonstration aboard the Neah Bay, a U.S. Coast Guard vessel stationed in Cleveland, Ohio, accomplished secure, seamless interoperability of mobile network systems across multiple domains without manual system reconfiguration. The Neah Bay was chosen because of its low cost and communications mission similarity to low-Earth-orbiting satellite platforms. This technology was successfully advanced from technology readiness level (TRL) 2 (concept and/or application formation) to TRL 6 (system model or prototype demonstration in a relevant environment). The secure, seamless interoperability offered by the Mobile Router and encryption device will enable several new, vehicle-specific and systemwide technologies to perform such things as remote, autonomous aircraft performance monitoring and early detection and mitigation of potential equipment malfunctions. As an additional benefit, team advancements were incorporated into open standards, ensuring technology transfer. Low-cost, commercial products incorporating the new technology are already available. Furthermore, these products are fully interoperable with legacy network technology equipment currently being used throughout the world.

Do learning collaboratives strengthen communication? A comparison of organizational team communication networks over time.

PubMed

Bunger, Alicia C; Lengnick-Hall, Rebecca

Collaborative learning models were designed to support quality improvements, such as innovation implementation by promoting communication within organizational teams. Yet the effect of collaborative learning approaches on organizational team communication during implementation is untested. The aim of this study was to explore change in communication patterns within teams from children's mental health organizations during a year-long learning collaborative focused on implementing a new treatment. We adopt a social network perspective to examine intraorganizational communication within each team and assess change in (a) the frequency of communication among team members, (b) communication across organizational hierarchies, and (c) the overall structure of team communication networks. A pretest-posttest design compared communication among 135 participants from 21 organizational teams at the start and end of a learning collaborative. At both time points, participants were asked to list the members of their team and rate the frequency of communication with each along a 7-point Likert scale. Several individual, pair-wise, and team level communication network metrics were calculated and compared over time. At the individual level, participants reported communicating with more team members by the end of the learning collaborative. Cross-hierarchical communication did not change. At the team level, these changes manifested differently depending on team size. In large teams, communication frequency increased, and networks grew denser and slightly less centralized. In small teams, communication frequency declined, growing more sparse and centralized. Results suggest that team communication patterns change minimally but evolve differently depending on size. Learning collaboratives may be more helpful for enhancing communication among larger teams; thus, managers might consider selecting and sending larger staff teams to learning collaboratives. This study highlights key future research directions that can disentangle the relationship between learning collaboratives and team networks.

47 CFR 80.148 - Watch on 156.8 MHz (Channel 16).

Code of Federal Regulations, 2010 CFR

2010-10-01

... exchanging communications. For GMDSS ships, 156.525 MHz is the calling frequency for distress, safety, and general communications using digital selective calling and the watch on 156.800 MHz is provided so that... 80.148 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) SAFETY AND SPECIAL RADIO...

78 FR 26572 - Rural Call Completion and List of Rural Operating Carrier Numbers

Federal Register 2010, 2011, 2012, 2013, 2014

2013-05-07

... FEDERAL COMMUNICATIONS COMMISSION 47 CFR Part 64 [WC Docket No. 13-39; DA 13-780] Rural Call Completion and List of Rural Operating Carrier Numbers AGENCY: Federal Communications Commission. ACTION: Proposed rule. SUMMARY: In this document, the Federal Communications Commission's Wireline Competition...

Advanced information society(5)

NASA Astrophysics Data System (ADS)

Tanizawa, Ippei

Based on the advancement of information network technology information communication forms informationalized society giving significant impact on business activities and life style in it. The information network has been backed up technologically by development of computer technology and has got great contribution by enhanced computer technology and communication equipments. Information is transferred by digital and analog methods. Technical development which has brought out multifunctioned modems of communication equipments in analog mode, and construction of advanced information communication network which has come out by joint work of computer and communication under digital technique, are described. The trend in institutional matter and standardization of electrical communication is also described showing some examples of value-added network (VAN).

Trainable Gene Regulation Networks with Applications to Drosophila Pattern Formation

NASA Technical Reports Server (NTRS)

Mjolsness, Eric

2000-01-01

This chapter will very briefly introduce and review some computational experiments in using trainable gene regulation network models to simulate and understand selected episodes in the development of the fruit fly, Drosophila melanogaster. For details the reader is referred to the papers introduced below. It will then introduce a new gene regulation network model which can describe promoter-level substructure in gene regulation. As described in chapter 2, gene regulation may be thought of as a combination of cis-acting regulation by the extended promoter of a gene (including all regulatory sequences) by way of the transcription complex, and of trans-acting regulation by the transcription factor products of other genes. If we simplify the cis-action by using a phenomenological model which can be tuned to data, such as a unit or other small portion of an artificial neural network, then the full transacting interaction between multiple genes during development can be modelled as a larger network which can again be tuned or trained to data. The larger network will in general need to have recurrent (feedback) connections since at least some real gene regulation networks do. This is the basic modeling approach taken, which describes how a set of recurrent neural networks can be used as a modeling language for multiple developmental processes including gene regulation within a single cell, cell-cell communication, and cell division. Such network models have been called "gene circuits", "gene regulation networks", or "genetic regulatory networks", sometimes without distinguishing the models from the actual modeled systems.

Occupational voice demands and their impact on the call-centre industry.

PubMed

Hazlett, D E; Duffy, O M; Moorhead, S A

2009-04-20

Within the last decade there has been a growth in the call-centre industry in the UK, with a growing awareness of the voice as an important tool for successful communication. Occupational voice problems such as occupational dysphonia, in a business which relies on healthy, effective voice as the primary professional communication tool, may threaten working ability and occupational health and safety of workers. While previous studies of telephone call-agents have reported a range of voice symptoms and functional vocal health problems, there have been no studies investigating the use and impact of vocal performance in the communication industry within the UK. This study aims to address a significant gap in the evidence-base of occupational health and safety research. The objectives of the study are: 1. to investigate the work context and vocal communication demands for call-agents; 2. to evaluate call-agents' vocal health, awareness and performance; and 3. to identify key risks and training needs for employees and employers within call-centres. This is an occupational epidemiological study, which plans to recruit call-centres throughout the UK and Ireland. Data collection will consist of three components: 1. interviews with managers from each participating call-centre to assess their communication and training needs; 2. an online biopsychosocial questionnaire will be administered to investigate the work environment and vocal demands of call-agents; and 3. voice acoustic measurements of a random sample of participants using the Multi-dimensional Voice Program (MDVP). Qualitative content analysis from the interviews will identify underlying themes and issues. A multivariate analysis approach will be adopted using Structural Equation Modelling (SEM), to develop voice measurement models in determining the construct validity of potential factors contributing to occupational dysphonia. Quantitative data will be analysed using SPSS version 15. Ethical approval is granted for this study from the School of Communication, University of Ulster. The results from this study will provide the missing element of voice-based evidence, by appraising the interactional dimensions of vocal health and communicative performance. This information will be used to inform training for call-agents and to contribute to health policies within the workplace, in order to enhance vocal health.

Comparing genomes to computer operating systems in terms of the topology and evolution of their regulatory control networks

PubMed Central

Yan, Koon-Kiu; Fang, Gang; Bhardwaj, Nitin; Alexander, Roger P.; Gerstein, Mark

2010-01-01

The genome has often been called the operating system (OS) for a living organism. A computer OS is described by a regulatory control network termed the call graph, which is analogous to the transcriptional regulatory network in a cell. To apply our firsthand knowledge of the architecture of software systems to understand cellular design principles, we present a comparison between the transcriptional regulatory network of a well-studied bacterium (Escherichia coli) and the call graph of a canonical OS (Linux) in terms of topology and evolution. We show that both networks have a fundamentally hierarchical layout, but there is a key difference: The transcriptional regulatory network possesses a few global regulators at the top and many targets at the bottom; conversely, the call graph has many regulators controlling a small set of generic functions. This top-heavy organization leads to highly overlapping functional modules in the call graph, in contrast to the relatively independent modules in the regulatory network. We further develop a way to measure evolutionary rates comparably between the two networks and explain this difference in terms of network evolution. The process of biological evolution via random mutation and subsequent selection tightly constrains the evolution of regulatory network hubs. The call graph, however, exhibits rapid evolution of its highly connected generic components, made possible by designers’ continual fine-tuning. These findings stem from the design principles of the two systems: robustness for biological systems and cost effectiveness (reuse) for software systems. PMID:20439753

Comparing genomes to computer operating systems in terms of the topology and evolution of their regulatory control networks.

PubMed

Yan, Koon-Kiu; Fang, Gang; Bhardwaj, Nitin; Alexander, Roger P; Gerstein, Mark

2010-05-18

The genome has often been called the operating system (OS) for a living organism. A computer OS is described by a regulatory control network termed the call graph, which is analogous to the transcriptional regulatory network in a cell. To apply our firsthand knowledge of the architecture of software systems to understand cellular design principles, we present a comparison between the transcriptional regulatory network of a well-studied bacterium (Escherichia coli) and the call graph of a canonical OS (Linux) in terms of topology and evolution. We show that both networks have a fundamentally hierarchical layout, but there is a key difference: The transcriptional regulatory network possesses a few global regulators at the top and many targets at the bottom; conversely, the call graph has many regulators controlling a small set of generic functions. This top-heavy organization leads to highly overlapping functional modules in the call graph, in contrast to the relatively independent modules in the regulatory network. We further develop a way to measure evolutionary rates comparably between the two networks and explain this difference in terms of network evolution. The process of biological evolution via random mutation and subsequent selection tightly constrains the evolution of regulatory network hubs. The call graph, however, exhibits rapid evolution of its highly connected generic components, made possible by designers' continual fine-tuning. These findings stem from the design principles of the two systems: robustness for biological systems and cost effectiveness (reuse) for software systems.

MILCOM '85 - Military Communications Conference, Boston, MA, October 20-23, 1985, Conference Record. Volumes 1, 2, & 3

NASA Astrophysics Data System (ADS)

The present conference on the development status of communications systems in the context of electronic warfare gives attention to topics in spread spectrum code acquisition, digital speech technology, fiber-optics communications, free space optical communications, the networking of HF systems, and applications and evaluation methods for digital speech. Also treated are issues in local area network system design, coding techniques and applications, technology applications for HF systems, receiver technologies, software development status, channel simultion/prediction methods, C3 networking spread spectrum networks, the improvement of communication efficiency and reliability through technical control methods, mobile radio systems, and adaptive antenna arrays. Finally, communications system cost analyses, spread spectrum performance, voice and image coding, switched networks, and microwave GaAs ICs, are considered.

13 CFR 400.104 - Meetings and actions of the Board.

Code of Federal Regulations, 2010 CFR

2010-01-01

... call communications equipment. Any member may participate in a meeting of the Board through the use of conference call, telephone or similar communications equipment, by means of which all persons participating... frequency. The Board meets, on the call of the Chairman, in order to consider matters requiring action by...

13 CFR 500.104 - Meetings and actions of the Board.

Code of Federal Regulations, 2010 CFR

2010-01-01

... call communications equipment. Any member may participate in a meeting of the Board through the use of conference call, telephone or similar communications equipment, by means of which all persons participating.... (a) Place and frequency. The Board meets, on the call of the Chairman, in order to consider matters...

Connectivity Restoration in Wireless Sensor Networks via Space Network Coding.

PubMed

Uwitonze, Alfred; Huang, Jiaqing; Ye, Yuanqing; Cheng, Wenqing

2017-04-20

The problem of finding the number and optimal positions of relay nodes for restoring the network connectivity in partitioned Wireless Sensor Networks (WSNs) is Non-deterministic Polynomial-time hard (NP-hard) and thus heuristic methods are preferred to solve it. This paper proposes a novel polynomial time heuristic algorithm, namely, Relay Placement using Space Network Coding (RPSNC), to solve this problem, where Space Network Coding, also called Space Information Flow (SIF), is a new research paradigm that studies network coding in Euclidean space, in which extra relay nodes can be introduced to reduce the cost of communication. Unlike contemporary schemes that are often based on Minimum Spanning Tree (MST), Euclidean Steiner Minimal Tree (ESMT) or a combination of MST with ESMT, RPSNC is a new min-cost multicast space network coding approach that combines Delaunay triangulation and non-uniform partitioning techniques for generating a number of candidate relay nodes, and then linear programming is applied for choosing the optimal relay nodes and computing their connection links with terminals. Subsequently, an equilibrium method is used to refine the locations of the optimal relay nodes, by moving them to balanced positions. RPSNC can adapt to any density distribution of relay nodes and terminals, as well as any density distribution of terminals. The performance and complexity of RPSNC are analyzed and its performance is validated through simulation experiments.

Tracking fin whales in the northeast Pacific Ocean with a seafloor seismic network.

PubMed

Wilcock, William S D

2012-10-01

Ocean bottom seismometer (OBS) networks represent a tool of opportunity to study fin and blue whales. A small OBS network on the Juan de Fuca Ridge in the northeast Pacific Ocean in ~2.3 km of water recorded an extensive data set of 20-Hz fin whale calls. An automated method has been developed to identify arrival times based on instantaneous frequency and amplitude and to locate calls using a grid search even in the presence of a few bad arrival times. When only one whale is calling near the network, tracks can generally be obtained up to distances of ~15 km from the network. When the calls from multiple whales overlap, user supervision is required to identify tracks. The absolute and relative amplitudes of arrivals and their three-component particle motions provide additional constraints on call location but are not useful for extending the distance to which calls can be located. The double-difference method inverts for changes in relative call locations using differences in residuals for pairs of nearby calls recorded on a common station. The method significantly reduces the unsystematic component of the location error, especially when inconsistencies in arrival time observations are minimized by cross-correlation.

Advanced Communication and Networking Technologies for Mars Exploration

NASA Technical Reports Server (NTRS)

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

2001-01-01

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

Telerobotic surgery: applications on human patients and training with virtual reality.

PubMed

Rovetta, A; Bejczy, A K; Sala, R

1997-01-01

This paper deals with the developed researches and applications on telerobotic surgery, devoted to human patients and with training by virtual reality. The researches have been developed in cooperation between Telerobotics Laboratory, Department of Mechanics, Politecnico di Milano, Italy, and Automation and Control Section, Jet Propulsion Laboratory, Pasadena, USA. The researches carried to a telesurgery robotic operation on a dummy on 7th July 1993, by means of satellites communications, to a prostatic biopsy on a human patient on 1st September 1995 with optical fibers, to results on time delay effects, to results on virtual reality applications for training on laparoscopy and surgery. The search implied time delay when the control input originated in Politecnico di Milano, Italy. The results were satisfactory, but also pointed out the need for specific new control transformations to ease the operator's or surgeon's visual/mental workload for hand-eye coordination. In the same research, dummy force commands from JPL to Milan were sent, and were echoed immediately back to JPL, measuring the round-trip time of the command signal. This, to some degree, simulates a contact force feedback situation. The results were very surprising; despite the fact that the ISDN calls are closed and "private" calls, the round-trip time exhibited great variations not only between calls but also within the same call. The results proved that telerobotics and telecontrol may be applied to surgery. Time latency variations are caused by features of communication network, of sending and receiving end computer software. The problem and its solution is also an architectural issue, and considerable improvements are possible. Virtual reality in the application of the research is a strong support to training on virtual objects and not on living beings.

History, structure, and function of the Internet.

PubMed

Glowniak, J

1998-04-01

The Internet stands at the forefront of telecommunications in medicine. This worldwide system of computers had its beginnings in networking projects in the United States and western Europe in the 1960s and 1970s. The precursor of the Internet was ARPANET, a long-distance telecommunication network funded by the Department of Defense that linked together computers throughout the United States. In the 1980s, ARPANET was superseded by NSFNET, a series of networks created by the National Science Foundation, which established the present-day structure of the Internet. The physical structure of the Internet resembles and is integrated with the telephone system. Long-distance data transport services are provided by large telecommunication companies, called network service providers (NSPs), through high-capacity, high-speed national and international fiber optic cables. These transport services are accessed through Internet service providers, ISPs. ISPs, the equivalent of regional Bell operating companies, provide the physical link to the NSPs for individuals and organizations. Telecommunications on the Internet are standardized by a set of communications protocols, the TCP/IP protocol suite, that describe routing of messages over the Internet, computer naming conventions, and commonly used Internet services such as e-mail. At present, the Internet consists of over 20 million computer worldwide and is continuing to grow at a rapid rate. Along with the growth of the Internet, higher speed access methods are offering a range of new services such as real-time video and voice communications. Medical education, teaching, and research, as well as clinical practice, will be affected in numerous different ways by these advances.