McMPI – a managed-code message passing interface library for high performance communication in C#

OpenAIRE

Holmes, Daniel John

2012-01-01

This work endeavours to achieve technology transfer between established best-practice in academic high-performance computing and current techniques in commercial high-productivity computing. It shows that a credible high-performance message-passing communication library, with semantics and syntax following the Message-Passing Interface (MPI) Standard, can be built in pure C# (one of the .Net suite of computer languages). Message-passing has been the dominant paradigm in high-pe...

Public-channel cryptography based on mutual chaos pass filters.

Science.gov (United States)

Klein, Einat; Gross, Noam; Kopelowitz, Evi; Rosenbluh, Michael; Khaykovich, Lev; Kinzel, Wolfgang; Kanter, Ido

2006-10-01

We study the mutual coupling of chaotic lasers and observe both experimentally and in numeric simulations that there exists a regime of parameters for which two mutually coupled chaotic lasers establish isochronal synchronization, while a third laser coupled unidirectionally to one of the pair does not synchronize. We then propose a cryptographic scheme, based on the advantage of mutual coupling over unidirectional coupling, where all the parameters of the system are public knowledge. We numerically demonstrate that in such a scheme the two communicating lasers can add a message signal (compressed binary message) to the transmitted coupling signal and recover the message in both directions with high fidelity by using a mutual chaos pass filter procedure. An attacker, however, fails to recover an errorless message even if he amplifies the coupling signal.

Stampi: a message passing library for distributed parallel computing. User's guide

International Nuclear Information System (INIS)

Imamura, Toshiyuki; Koide, Hiroshi; Takemiya, Hiroshi

1998-11-01

A new message passing library, Stampi, has been developed to realize a computation with different kind of parallel computers arbitrarily and making MPI (Message Passing Interface) as an unique interface for communication. Stampi is based on MPI2 specification. It realizes dynamic process creation to different machines and communication between spawned one within the scope of MPI semantics. Vender implemented MPI as a closed system in one parallel machine and did not support both functions; process creation and communication to external machines. Stampi supports both functions and enables us distributed parallel computing. Currently Stampi has been implemented on COMPACS (COMplex PArallel Computer System) introduced in CCSE, five parallel computers and one graphic workstation, and any communication on them can be processed on. (author)

Chaos synchronization communication using extremely unsymmetrical bidirectional injections.

Science.gov (United States)

Zhang, Wei Li; Pan, Wei; Luo, Bin; Zou, Xi Hua; Wang, Meng Yao; Zhou, Zhi

2008-02-01

Chaos synchronization and message transmission between two semiconductor lasers with extremely unsymmetrical bidirectional injections (EUBIs) are discussed. By using EUBIs, synchronization is realized through injection locking. Numerical results show that if the laser subjected to strong injection serves as the receiver, chaos pass filtering (CPF) of the system is similar to that of unidirectional coupled systems. Moreover, if the other laser serves as the receiver, a stronger CPF can be obtained. Finally, we demonstrate that messages can be extracted successfully from either of the two transmission directions of the system.

A message passing algorithm for the evaluation of social influence

NARCIS (Netherlands)

Vassio, Luca; Fagnani, Fabio; Frasca, Paolo; Ozdaglar, Asuman

2014-01-01

In this paper, we define a new measure of node centrality in social networks, the Harmonic Influence Centrality, which emerges naturally in the study of social influence over networks. Next, we introduce a distributed message passing algorithm to compute the Harmonic Influence Centrality of each

Belief propagation decoding of quantum channels by passing quantum messages

International Nuclear Information System (INIS)

Renes, Joseph M

2017-01-01

The belief propagation (BP) algorithm is a powerful tool in a wide range of disciplines from statistical physics to machine learning to computational biology, and is ubiquitous in decoding classical error-correcting codes. The algorithm works by passing messages between nodes of the factor graph associated with the code and enables efficient decoding of the channel, in some cases even up to the Shannon capacity. Here we construct the first BP algorithm which passes quantum messages on the factor graph and is capable of decoding the classical–quantum channel with pure state outputs. This gives explicit decoding circuits whose number of gates is quadratic in the code length. We also show that this decoder can be modified to work with polar codes for the pure state channel and as part of a decoder for transmitting quantum information over the amplitude damping channel. These represent the first explicit capacity-achieving decoders for non-Pauli channels. (fast track communication)

Belief propagation decoding of quantum channels by passing quantum messages

Science.gov (United States)

Renes, Joseph M.

2017-07-01

The belief propagation (BP) algorithm is a powerful tool in a wide range of disciplines from statistical physics to machine learning to computational biology, and is ubiquitous in decoding classical error-correcting codes. The algorithm works by passing messages between nodes of the factor graph associated with the code and enables efficient decoding of the channel, in some cases even up to the Shannon capacity. Here we construct the first BP algorithm which passes quantum messages on the factor graph and is capable of decoding the classical-quantum channel with pure state outputs. This gives explicit decoding circuits whose number of gates is quadratic in the code length. We also show that this decoder can be modified to work with polar codes for the pure state channel and as part of a decoder for transmitting quantum information over the amplitude damping channel. These represent the first explicit capacity-achieving decoders for non-Pauli channels.

S-AMP: Approximate Message Passing for General Matrix Ensembles

DEFF Research Database (Denmark)

Cakmak, Burak; Winther, Ole; Fleury, Bernard H.

2014-01-01

the approximate message-passing (AMP) algorithm to general matrix ensembles with a well-defined large system size limit. The generalization is based on the S-transform (in free probability) of the spectrum of the measurement matrix. Furthermore, we show that the optimality of S-AMP follows directly from its......We propose a novel iterative estimation algorithm for linear observation models called S-AMP. The fixed points of S-AMP are the stationary points of the exact Gibbs free energy under a set of (first- and second-) moment consistency constraints in the large system limit. S-AMP extends...

Stampi: a message passing library for distributed parallel computing. User's guide, second edition

International Nuclear Information System (INIS)

Imamura, Toshiyuki; Koide, Hiroshi; Takemiya, Hiroshi

2000-02-01

A new message passing library, Stampi, has been developed to realize a computation with different kind of parallel computers arbitrarily and making MPI (Message Passing Interface) as an unique interface for communication. Stampi is based on the MPI2 specification, and it realizes dynamic process creation to different machines and communication between spawned one within the scope of MPI semantics. Main features of Stampi are summarized as follows: (i) an automatic switch function between external- and internal communications, (ii) a message routing/relaying with a routing module, (iii) a dynamic process creation, (iv) a support of two types of connection, Master/Slave and Client/Server, (v) a support of a communication with Java applets. Indeed vendors implemented MPI libraries as a closed system in one parallel machine or their systems, and did not support both functions; process creation and communication to external machines. Stampi supports both functions and enables us distributed parallel computing. Currently Stampi has been implemented on COMPACS (COMplex PArallel Computer System) introduced in CCSE, five parallel computers and one graphic workstation, moreover on eight kinds of parallel machines, totally fourteen systems. Stampi provides us MPI communication functionality on them. This report describes mainly the usage of Stampi. (author)

An adaptive synchronization strategy based on active control for demodulating message hidden in chaotic signals

International Nuclear Information System (INIS)

Tang Fang

2008-01-01

In the field of secure communication, it is very important to demodulate the message hidden in chaotic signals. In this paper, an adaptive synchronization strategy based on active control is proposed, which is used to design an active controller and an appropriate adaptive demodulator at the receiver to recover the transmitted message hidden in chaotic signals of a drive system. Based on Lyapunov stability theory, it is shown that the transmitted message can be theoretically recovered by using the proposed strategy. Numerical simulations based on the Chua's circuit are also presented to verify the effectiveness of the proposed strategy. In addition, it is shown via simulations that, by increasing the gain of the active controller the message error caused by the external noise and the discontinuous property of the message can be reduced

Chaos-pass filtering in injection-locked semiconductor lasers

International Nuclear Information System (INIS)

Murakami, Atsushi; Shore, K. Alan

2005-01-01

Chaos-pass filtering (CPF) of semiconductor lasers has been studied theoretically. CPF is a phenomenon which occurs in laser chaos synchronization by injection locking and is a fundamental technique for the extraction of messages at the receiver laser in chaotic communications systems. We employ a simple theory based on driven damped oscillators to clarify the physical background of CPF. The receiver laser is optically driven by injection from the transmitter laser. We have numerically investigated the response characteristics of the receiver when it is driven by periodic (message) and chaotic (carrier) signals. It is thereby revealed that the response of the receiver laser in the two cases is quite different. For the periodic drive, the receiver exhibits a response depending on the signal frequency, while the chaotic drive provides a frequency-independent synchronous response to the receiver laser. We verify that the periodic and chaotic drives occur independently in the CPF response, and, consequently, CPF can be clearly understood in the difference of the two drives. Message extraction using CPF is also examined, and the validity of our theoretical explanation for the physical mechanism underlying CPF is thus verified

Notified Access: Extending Remote Memory Access Programming Models for Producer-Consumer Synchronization

KAUST Repository

Belli, Roberto; Hoefler, Torsten

2015-01-01

Remote Memory Access (RMA) programming enables direct access to low-level hardware features to achieve high performance for distributed-memory programs. However, the design of RMA programming schemes focuses on the memory access and less on the synchronization. For example, in contemporary RMA programming systems, the widely used producer-consumer pattern can only be implemented inefficiently, incurring in an overhead of an additional round-trip message. We propose Notified Access, a scheme where the target process of an access can receive a completion notification. This scheme enables direct and efficient synchronization with a minimum number of messages. We implement our scheme in an open source MPI-3 RMA library and demonstrate lower overheads (two cache misses) than other point-to-point synchronization mechanisms for each notification. We also evaluate our implementation on three real-world benchmarks, a stencil computation, a tree computation, and a Colicky factorization implemented with tasks. Our scheme always performs better than traditional message passing and other existing RMA synchronization schemes, providing up to 50% speedup on small messages. Our analysis shows that Notified Access is a valuable primitive for any RMA system. Furthermore, we provide guidance for the design of low-level network interfaces to support Notified Access efficiently.

Notified Access: Extending Remote Memory Access Programming Models for Producer-Consumer Synchronization

KAUST Repository

Belli, Roberto

2015-05-01

Remote Memory Access (RMA) programming enables direct access to low-level hardware features to achieve high performance for distributed-memory programs. However, the design of RMA programming schemes focuses on the memory access and less on the synchronization. For example, in contemporary RMA programming systems, the widely used producer-consumer pattern can only be implemented inefficiently, incurring in an overhead of an additional round-trip message. We propose Notified Access, a scheme where the target process of an access can receive a completion notification. This scheme enables direct and efficient synchronization with a minimum number of messages. We implement our scheme in an open source MPI-3 RMA library and demonstrate lower overheads (two cache misses) than other point-to-point synchronization mechanisms for each notification. We also evaluate our implementation on three real-world benchmarks, a stencil computation, a tree computation, and a Colicky factorization implemented with tasks. Our scheme always performs better than traditional message passing and other existing RMA synchronization schemes, providing up to 50% speedup on small messages. Our analysis shows that Notified Access is a valuable primitive for any RMA system. Furthermore, we provide guidance for the design of low-level network interfaces to support Notified Access efficiently.

A message-passing approach to random constraint satisfaction problems with growing domains

International Nuclear Information System (INIS)

Zhao, Chunyan; Zheng, Zhiming; Zhou, Haijun; Xu, Ke

2011-01-01

Message-passing algorithms based on belief propagation (BP) are implemented on a random constraint satisfaction problem (CSP) referred to as model RB, which is a prototype of hard random CSPs with growing domain size. In model RB, the number of candidate discrete values (the domain size) of each variable increases polynomially with the variable number N of the problem formula. Although the satisfiability threshold of model RB is exactly known, finding solutions for a single problem formula is quite challenging and attempts have been limited to cases of N ∼ 10 2 . In this paper, we propose two different kinds of message-passing algorithms guided by BP for this problem. Numerical simulations demonstrate that these algorithms allow us to find a solution for random formulas of model RB with constraint tightness slightly less than p cr , the threshold value for the satisfiability phase transition. To evaluate the performance of these algorithms, we also provide a local search algorithm (random walk) as a comparison. Besides this, the simulated time dependence of the problem size N and the entropy of the variables for growing domain size are discussed

Space Reclamation for Uncoordinated Checkpointing in Message-Passing Systems. Ph.D. Thesis

Science.gov (United States)

Wang, Yi-Min

1993-01-01

Checkpointing and rollback recovery are techniques that can provide efficient recovery from transient process failures. In a message-passing system, the rollback of a message sender may cause the rollback of the corresponding receiver, and the system needs to roll back to a consistent set of checkpoints called recovery line. If the processes are allowed to take uncoordinated checkpoints, the above rollback propagation may result in the domino effect which prevents recovery line progression. Traditionally, only obsolete checkpoints before the global recovery line can be discarded, and the necessary and sufficient condition for identifying all garbage checkpoints has remained an open problem. A necessary and sufficient condition for achieving optimal garbage collection is derived and it is proved that the number of useful checkpoints is bounded by N(N+1)/2, where N is the number of processes. The approach is based on the maximum-sized antichain model of consistent global checkpoints and the technique of recovery line transformation and decomposition. It is also shown that, for systems requiring message logging to record in-transit messages, the same approach can be used to achieve optimal message log reclamation. As a final topic, a unifying framework is described by considering checkpoint coordination and exploiting piecewise determinism as mechanisms for bounding rollback propagation, and the applicability of the optimal garbage collection algorithm to domino-free recovery protocols is demonstrated.

A Message-Passing Hardware/Software Cosimulation Environment for Reconfigurable Computing Systems

Directory of Open Access Journals (Sweden)

Manuel Saldaña

2009-01-01

Full Text Available High-performance reconfigurable computers (HPRCs provide a mix of standard processors and FPGAs to collectively accelerate applications. This introduces new design challenges, such as the need for portable programming models across HPRCs and system-level verification tools. To address the need for cosimulating a complete heterogeneous application using both software and hardware in an HPRC, we have created a tool called the Message-passing Simulation Framework (MSF. We have used it to simulate and develop an interface enabling an MPI-based approach to exchange data between X86 processors and hardware engines inside FPGAs. The MSF can also be used as an application development tool that enables multiple FPGAs in simulation to exchange messages amongst themselves and with X86 processors. As an example, we simulate a LINPACK benchmark hardware core using an Intel-FSB-Xilinx-FPGA platform to quickly prototype the hardware, to test the communications. and to verify the benchmark results.

Simple Algorithms for Distributed Leader Election in Anonymous Synchronous Rings and Complete Networks Inspired by Neural Development in Fruit Flies.

Science.gov (United States)

Xu, Lei; Jeavons, Peter

2015-11-01

Leader election in anonymous rings and complete networks is a very practical problem in distributed computing. Previous algorithms for this problem are generally designed for a classical message passing model where complex messages are exchanged. However, the need to send and receive complex messages makes such algorithms less practical for some real applications. We present some simple synchronous algorithms for distributed leader election in anonymous rings and complete networks that are inspired by the development of the neural system of the fruit fly. Our leader election algorithms all assume that only one-bit messages are broadcast by nodes in the network and processors are only able to distinguish between silence and the arrival of one or more messages. These restrictions allow implementations to use a simpler message-passing architecture. Even with these harsh restrictions our algorithms are shown to achieve good time and message complexity both analytically and experimentally.

Parallelization of a hydrological model using the message passing interface

Science.gov (United States)

Wu, Yiping; Li, Tiejian; Sun, Liqun; Chen, Ji

2013-01-01

With the increasing knowledge about the natural processes, hydrological models such as the Soil and Water Assessment Tool (SWAT) are becoming larger and more complex with increasing computation time. Additionally, other procedures such as model calibration, which may require thousands of model iterations, can increase running time and thus further reduce rapid modeling and analysis. Using the widely-applied SWAT as an example, this study demonstrates how to parallelize a serial hydrological model in a Windows® environment using a parallel programing technology—Message Passing Interface (MPI). With a case study, we derived the optimal values for the two parameters (the number of processes and the corresponding percentage of work to be distributed to the master process) of the parallel SWAT (P-SWAT) on an ordinary personal computer and a work station. Our study indicates that model execution time can be reduced by 42%–70% (or a speedup of 1.74–3.36) using multiple processes (two to five) with a proper task-distribution scheme (between the master and slave processes). Although the computation time cost becomes lower with an increasing number of processes (from two to five), this enhancement becomes less due to the accompanied increase in demand for message passing procedures between the master and all slave processes. Our case study demonstrates that the P-SWAT with a five-process run may reach the maximum speedup, and the performance can be quite stable (fairly independent of a project size). Overall, the P-SWAT can help reduce the computation time substantially for an individual model run, manual and automatic calibration procedures, and optimization of best management practices. In particular, the parallelization method we used and the scheme for deriving the optimal parameters in this study can be valuable and easily applied to other hydrological or environmental models.

Partition function expansion on region graphs and message-passing equations

International Nuclear Information System (INIS)

Zhou, Haijun; Wang, Chuang; Xiao, Jing-Qing; Bi, Zedong

2011-01-01

Disordered and frustrated graphical systems are ubiquitous in physics, biology, and information science. For models on complete graphs or random graphs, deep understanding has been achieved through the mean-field replica and cavity methods. But finite-dimensional 'real' systems remain very challenging because of the abundance of short loops and strong local correlations. A statistical mechanics theory is constructed in this paper for finite-dimensional models based on the mathematical framework of the partition function expansion and the concept of region graphs. Rigorous expressions for the free energy and grand free energy are derived. Message-passing equations on the region graph, such as belief propagation and survey propagation, are also derived rigorously. (letter)

Distributed primal–dual interior-point methods for solving tree-structured coupled convex problems using message-passing

DEFF Research Database (Denmark)

Khoshfetrat Pakazad, Sina; Hansson, Anders; Andersen, Martin S.

2017-01-01

In this paper, we propose a distributed algorithm for solving coupled problems with chordal sparsity or an inherent tree structure which relies on primal–dual interior-point methods. We achieve this by distributing the computations at each iteration, using message-passing. In comparison to existi...

Message Embedded Chaotic Masking Synchronization Scheme Based on the Generalized Lorenz System and Its Security Analysis

Czech Academy of Sciences Publication Activity Database

Čelikovský, Sergej; Lynnyk, Volodymyr

2016-01-01

Roč. 26, č. 8 (2016), 1650140-1-1650140-15 ISSN 0218-1274 R&D Projects: GA ČR GA13-20433S Institutional support: RVO:67985556 Keywords : Chaotic masking * generalized Lorenz system * message embedded synchronization Subject RIV: BC - Control Systems Theory Impact factor: 1.329, year: 2016 http://library.utia.cas.cz/separaty/2016/TR/celikovsky-0461536.pdf

Design of a Message Passing Model for Use in a Heterogeneous CPU-NFP Framework for Network Analytics

CSIR Research Space (South Africa)

Pennefather, S

2017-09-01

Full Text Available of applications written in the Go programming language to be executed on a Network Flow Processor (NFP) for enhanced performance. This paper explores the need and feasibility of implementing a message passing model for data transmission between the NFP and CPU...

The specification of Stampi, a message passing library for distributed parallel computing

International Nuclear Information System (INIS)

Imamura, Toshiyuki; Takemiya, Hiroshi; Koide, Hiroshi

2000-03-01

At CCSE, Center for Promotion of Computational Science and Engineering, a new message passing library for heterogeneous and distributed parallel computing has been developed, and it is called as Stampi. Stampi enables us to communicate between any combination of parallel computers as well as workstations. Currently, a Stampi system is constructed from Stampi library and Stampi/Java. It provides functions to connect a Stampi application with not only those on COMPACS, COMplex Parallel Computer System, but also applets which work on WWW browsers. This report summarizes the specifications of Stampi and details the development of its system. (author)

A real-time MPEG software decoder using a portable message-passing library

Energy Technology Data Exchange (ETDEWEB)

Kwong, Man Kam; Tang, P.T. Peter; Lin, Biquan

1995-12-31

We present a real-time MPEG software decoder that uses message-passing libraries such as MPL, p4 and MPI. The parallel MPEG decoder currently runs on the IBM SP system but can be easil ported to other parallel machines. This paper discusses our parallel MPEG decoding algorithm as well as the parallel programming environment under which it uses. Several technical issues are discussed, including balancing of decoding speed, memory limitation, 1/0 capacities, and optimization of MPEG decoding components. This project shows that a real-time portable software MPEG decoder is feasible in a general-purpose parallel machine.

Can rare SAT formulae be easily recognized? On the efficiency of message-passing algorithms for K-SAT at large clause-to-variable ratios

International Nuclear Information System (INIS)

Altarelli, Fabrizio; Monasson, Remi; Zamponi, Francesco

2007-01-01

For large clause-to-variable ratios, typical K-SAT instances drawn from the uniform distribution have no solution. We argue, based on statistical mechanics calculations using the replica and cavity methods, that rare satisfiable instances from the uniform distribution are very similar to typical instances drawn from the so-called planted distribution, where instances are chosen uniformly between the ones that admit a given solution. It then follows, from a recent article by Feige, Mossel and Vilenchik (2006 Complete convergence of message passing algorithms for some satisfiability problems Proc. Random 2006 pp 339-50), that these rare instances can be easily recognized (in O(log N) time and with probability close to 1) by a simple message-passing algorithm

Parallelization of MCNP Monte Carlo neutron and photon transport code in parallel virtual machine and message passing interface

International Nuclear Information System (INIS)

Deng Li; Xie Zhongsheng

1999-01-01

The coupled neutron and photon transport Monte Carlo code MCNP (version 3B) has been parallelized in parallel virtual machine (PVM) and message passing interface (MPI) by modifying a previous serial code. The new code has been verified by solving sample problems. The speedup increases linearly with the number of processors and the average efficiency is up to 99% for 12-processor. (author)

What it Takes to Get Passed On: Message Content, Style, and Structure as Predictors of Retransmission in the Boston Marathon Bombing Response.

Directory of Open Access Journals (Sweden)

Jeannette Sutton

Full Text Available Message retransmission is a central aspect of information diffusion. In a disaster context, the passing on of official warning messages by members of the public also serves as a behavioral indicator of message salience, suggesting that particular messages are (or are not perceived by the public to be both noteworthy and valuable enough to share with others. This study provides the first examination of terse message retransmission of official warning messages in response to a domestic terrorist attack, the Boston Marathon Bombing in 2013. Using messages posted from public officials' Twitter accounts that were active during the period of the Boston Marathon bombing and manhunt, we examine the features of messages that are associated with their retransmission. We focus on message content, style, and structure, as well as the networked relationships of message senders to answer the question: what characteristics of a terse message sent under conditions of imminent threat predict its retransmission among members of the public? We employ a negative binomial model to examine how message characteristics affect message retransmission. We find that, rather than any single effect dominating the process, retransmission of official Tweets during the Boston bombing response was jointly influenced by various message content, style, and sender characteristics. These findings suggest the need for more work that investigates impact of multiple factors on the allocation of attention and on message retransmission during hazard events.

Statistical Physics, Optimization, Inference, and Message-Passing Algorithms : Lecture Notes of the Les Houches School of Physics : Special Issue, October 2013

CERN Document Server

Ricci-Tersenghi, Federico; Zdeborova, Lenka; Zecchina, Riccardo; Tramel, Eric W; Cugliandolo, Leticia F

2015-01-01

This book contains a collection of the presentations that were given in October 2013 at the Les Houches Autumn School on statistical physics, optimization, inference, and message-passing algorithms. In the last decade, there has been increasing convergence of interest and methods between theoretical physics and fields as diverse as probability, machine learning, optimization, and inference problems. In particular, much theoretical and applied work in statistical physics and computer science has relied on the use of message-passing algorithms and their connection to the statistical physics of glasses and spin glasses. For example, both the replica and cavity methods have led to recent advances in compressed sensing, sparse estimation, and random constraint satisfaction, to name a few. This book’s detailed pedagogical lectures on statistical inference, computational complexity, the replica and cavity methods, and belief propagation are aimed particularly at PhD students, post-docs, and young researchers desir...

Communication with spatial periodic chaos synchronization

International Nuclear Information System (INIS)

Zhou, J.; Huang, H.B.; Qi, G.X.; Yang, P.; Xie, X.

2005-01-01

Based on the spatial periodic chaos synchronization in coupled ring and linear arrays, we proposed a random high-dimensional chaotic encryption scheme. The transmitter can choose hyperchaotic signals randomly from the ring at any different time and simultaneously transmit the information of chaotic oscillators in the ring to receiver through public channel, so that the message can be masked by different hyperchaotic signals in different time intervals during communication, and the receiver can decode the message based on chaos synchronization but the attacker does not know the random hyperchaotic dynamics and cannot decode the message. Furthermore, the high sensitivity to the symmetry of the coupling structure makes the attacker very difficult to obtain any useful message from the channel

Selection of the signal synchronization method in software GPS receivers

Directory of Open Access Journals (Sweden)

Vlada S. Sokolović

2011-04-01

Full Text Available Introduction This paper presents a critical analysis of the signal processing flow carried out in a software GPS receiver and a critical comparison of different architectures for signal processing within the GPS receiver. A model of software receivers is shown. Based on the displayed model, a receiver has been realized in the MATLAB software package, in which the simulations of signal processing were carried out. The aim of this paper is to demonstrate the advantages and disadvantages of different methods of the synchronization of signals in the receiver, and to propose a solution acceptable for possible implementation. The signal processing flow was observed from the input circuit to the extraction of the bits of the navigation message. The entire signal processing was performed on the L1 signal and the data collected by the input circuit SE4110. A radio signal from the satellite was accepted with the input circuit, filtered and translated into a digital form. The input circuit ends with the hardware of the receiver. A digital signal from the input circuit is brought into the PC Pentium 4 (AMD 3000 + where the receiver is realized in Matlab. Model of software GPS receiver The first level of processing is signal acquisition. Signal acquisition was realized using the cyclic convolution. The acquisition process was carried out by measuring signals from satellites, and these parameters are passed to the next level of processing. The next level was done by monitoring the synchronization signal and extracting the navigation message bits. On the basis of the detection of the navigation message the receiver calculates the position of a satellite and then, based on the position of the satellite, its own position. Tracking of GPS signal synchronization In order to select the most acceptable method of signal synchronization in the receiver, different methods of signal synchronization are compared. The early-late-DLL (Delay Lock Loop, TDL (Tau Dither Loop

Weighted community detection and data clustering using message passing

Science.gov (United States)

Shi, Cheng; Liu, Yanchen; Zhang, Pan

2018-03-01

Grouping objects into clusters based on the similarities or weights between them is one of the most important problems in science and engineering. In this work, by extending message-passing algorithms and spectral algorithms proposed for an unweighted community detection problem, we develop a non-parametric method based on statistical physics, by mapping the problem to the Potts model at the critical temperature of spin-glass transition and applying belief propagation to solve the marginals corresponding to the Boltzmann distribution. Our algorithm is robust to over-fitting and gives a principled way to determine whether there are significant clusters in the data and how many clusters there are. We apply our method to different clustering tasks. In the community detection problem in weighted and directed networks, we show that our algorithm significantly outperforms existing algorithms. In the clustering problem, where the data were generated by mixture models in the sparse regime, we show that our method works all the way down to the theoretical limit of detectability and gives accuracy very close to that of the optimal Bayesian inference. In the semi-supervised clustering problem, our method only needs several labels to work perfectly in classic datasets. Finally, we further develop Thouless-Anderson-Palmer equations which heavily reduce the computation complexity in dense networks but give almost the same performance as belief propagation.

Message passing vs. shared address space on a cluster of SMPs

International Nuclear Information System (INIS)

Shan, Hongzhang; Singh, Jaswinder Pal; Oliker, Leonid; Biswas, Rupak

2001-01-01

The emergence of scalable computer architectures using clusters of PCs or PC-SMPs with commodity networking has made them attractive platforms for high-end scientific computing. Currently, message passing (MP) and shared address space (SAS) are the two leading programming paradigms for these systems. MP has been standardized with MPI, and is the most common and mature parallel programming approach. However, MP code development can be extremely difficult, especially for irregularly structured computations. SAS offers substantial ease of programming, but may suffer from performance limitations due to poor spatial locality and high protocol overhead. In this paper, they compare the performance of and programming effort required for six applications under both programming models on a 32-CPU PC-SMP cluster. Our application suite consists of codes that typically do not exhibit scalable performance under shared-memory programming due to their high communication-to-computation ratios and complex communication patterns. Results indicate that SAS can achieve about half the parallel efficiency of MPI for most of the applications; however, on certain classes of problems, SAS performance is competitive with MPI

Technical Evaluation Report 6: Chat and Instant Messaging Systems

Directory of Open Access Journals (Sweden)

Jennifer Stein

2002-04-01

Full Text Available Text-based conferencing can be both asynchronous (i.e., participants log into the conference at separate times, and synchronous (i.e., interaction takes place in real time. It is thus subject to the same wide variation as the online audio- and video-conferencing methods (see the earlier Reports in this series. Synchronous text-based approaches (e.g., online chat groups and instant messaging systems are highly popular among online users generally owing to their ability to bring together special-interest groups from around the world without cost. In distance education (DE, however, synchronous chat methods are less widely used, owing in part to the problems of arranging for working adults in different time zones to join a discussion group simultaneously. Instant text messaging is more popular among DE users in view of the choice it provides between responding to a message immediately (synchronous communication or after a delay (asynchronous. The different synchronous and asynchronous approaches are likely to become more widely used in parallel with one another, as they are integrated in individual product packages.

Approximate message passing for nonconvex sparse regularization with stability and asymptotic analysis

Science.gov (United States)

Sakata, Ayaka; Xu, Yingying

2018-03-01

We analyse a linear regression problem with nonconvex regularization called smoothly clipped absolute deviation (SCAD) under an overcomplete Gaussian basis for Gaussian random data. We propose an approximate message passing (AMP) algorithm considering nonconvex regularization, namely SCAD-AMP, and analytically show that the stability condition corresponds to the de Almeida-Thouless condition in spin glass literature. Through asymptotic analysis, we show the correspondence between the density evolution of SCAD-AMP and the replica symmetric (RS) solution. Numerical experiments confirm that for a sufficiently large system size, SCAD-AMP achieves the optimal performance predicted by the replica method. Through replica analysis, a phase transition between replica symmetric and replica symmetry breaking (RSB) region is found in the parameter space of SCAD. The appearance of the RS region for a nonconvex penalty is a significant advantage that indicates the region of smooth landscape of the optimization problem. Furthermore, we analytically show that the statistical representation performance of the SCAD penalty is better than that of \

Fault-tolerant clock synchronization in distributed systems

Science.gov (United States)

Ramanathan, Parameswaran; Shin, Kang G.; Butler, Ricky W.

1990-01-01

Existing fault-tolerant clock synchronization algorithms are compared and contrasted. These include the following: software synchronization algorithms, such as convergence-averaging, convergence-nonaveraging, and consistency algorithms, as well as probabilistic synchronization; hardware synchronization algorithms; and hybrid synchronization. The worst-case clock skews guaranteed by representative algorithms are compared, along with other important aspects such as time, message, and cost overhead imposed by the algorithms. More recent developments such as hardware-assisted software synchronization and algorithms for synchronizing large, partially connected distributed systems are especially emphasized.

Breaking projective chaos synchronization secure communication using filtering and generalized synchronization

International Nuclear Information System (INIS)

Alvarez, G.; Li Shujun; Montoya, F.; Pastor, G.; Romera, M.

2005-01-01

This paper describes the security weaknesses of a recently proposed secure communication method based on chaotic masking using projective synchronization of two chaotic systems. We show that the system is insecure and how to break it in two different ways, by high-pass filtering and by generalized synchronization

The beam synchronous timing system for the LEP instrumentation

International Nuclear Information System (INIS)

Baribaud, G.; Brahy, D.; Cojan, A.; Momal, F.; Rabany, M.; Saban, R.; Wolles, J.C.

1990-01-01

The beam instrumentation group of LEP has constructed a number of detectors distributed around the collider: these instruments are interfaced to approximately 100 VME-based computers which acquire and process data autonomously. In order to ensure the coherence of a measurement and to correlate measurements of different instruments, it is essential that the data are acquired at the same moment on all the systems. The beam synchronous timing system ensures this by broadcasting messages that describe to all instruments the action to be performed. The instructions are guaranteed to arrive at exactly the same moment to all stations around the 27 km circumference by careful compensation of the delay for each station. The heart of the system is a commercial 25 MHz 68020-based VME module coupled to an in-house designed message assembler: these are able to synthesize instructions for up to six different kinds of instruments in a single LEP revolution (89 μs). Each listening station provides the hardware with pulses derived from the incoming message, filters the messages according to the addresses and passes them to real-time tasks which set the hardware or acquire the data. A reverse channel, peripheral station to the control room, allows up to eight different signals to inform the master of locally detected events such as beam loss or high background. Special recovery instructions can then be broadcast. (orig.)

Balancing Contention and Synchronization on the Intel Paragon

Science.gov (United States)

Bokhari, Shahid H.; Nicol, David M.

1996-01-01

The Intel Paragon is a mesh-connected distributed memory parallel computer. It uses an oblivious and deterministic message routing algorithm: this permits us to develop highly optimized schedules for frequently needed communication patterns. The complete exchange is one such pattern. Several approaches are available for carrying it out on the mesh. We study an algorithm developed by Scott. This algorithm assumes that a communication link can carry one message at a time and that a node can only transmit one message at a time. It requires global synchronization to enforce a schedule of transmissions. Unfortunately global synchronization has substantial overhead on the Paragon. At the same time the powerful interconnection mechanism of this machine permits 2 or 3 messages to share a communication link with minor overhead. It can also overlap multiple message transmission from the same node to some extent. We develop a generalization of Scott's algorithm that executes complete exchange with a prescribed contention. Schedules that incur greater contention require fewer synchronization steps. This permits us to tradeoff contention against synchronization overhead. We describe the performance of this algorithm and compare it with Scott's original algorithm as well as with a naive algorithm that does not take interconnection structure into account. The Bounded contention algorithm is always better than Scott's algorithm and outperforms the naive algorithm for all but the smallest message sizes. The naive algorithm fails to work on meshes larger than 12 x 12. These results show that due consideration of processor interconnect and machine performance parameters is necessary to obtain peak performance from the Paragon and its successor mesh machines.

Global synchronization algorithms for the Intel iPSC/860

Science.gov (United States)

Seidel, Steven R.; Davis, Mark A.

1992-01-01

In a distributed memory multicomputer that has no global clock, global processor synchronization can only be achieved through software. Global synchronization algorithms are used in tridiagonal systems solvers, CFD codes, sequence comparison algorithms, and sorting algorithms. They are also useful for event simulation, debugging, and for solving mutual exclusion problems. For the Intel iPSC/860 in particular, global synchronization can be used to ensure the most effective use of the communication network for operations such as the shift, where each processor in a one-dimensional array or ring concurrently sends a message to its right (or left) neighbor. Three global synchronization algorithms are considered for the iPSC/860: the gysnc() primitive provided by Intel, the PICL primitive sync0(), and a new recursive doubling synchronization (RDS) algorithm. The performance of these algorithms is compared to the performance predicted by communication models of both the long and forced message protocols. Measurements of the cost of shift operations preceded by global synchronization show that the RDS algorithm always synchronizes the nodes more precisely and costs only slightly more than the other two algorithms.

Synchronization and bidirectional communication without delay line using strong mutually coupled semiconductor lasers

Science.gov (United States)

Li, Guang-Hui; Wang, An-Bang; Feng, Ye; Wang, Yang

2010-07-01

This paper numerically demonstrates synchronization and bidirectional communication without delay line by using two semiconductor lasers with strong mutual injection in a face-to-face configuration. These results show that both of the two lasers' outputs synchronize with their input chaotic carriers. In addition, simulations demonstrate that this kind of synchronization can be used to realize bidirectional communications without delay line. Further studies indicate that within a small deviation in message amplitudes of two sides (±6%), the message can be extracted with signal-noise-ratio more than 10 dB; and the signal-noise-ratio is extremely sensitive to the message rates mismatch of two sides, which may be used as a key of bidirectional communication.

Synchronization and bidirectional communication without delay line using strong mutually coupled semiconductor lasers

International Nuclear Information System (INIS)

Guang-Hui, Li; An-Bang, Wang; Ye, Feng; Yang, Wang

2010-01-01

This paper numerically demonstrates synchronization and bidirectional communication without delay line by using two semiconductor lasers with strong mutual injection in a face-to-face configuration. These results show that both of the two lasers' outputs synchronize with their input chaotic carriers. In addition, simulations demonstrate that this kind of synchronization can be used to realize bidirectional communications without delay line. Further studies indicate that within a small deviation in message amplitudes of two sides (±6%), the message can be extracted with signal-noise-ratio more than 10 dB; and the signal-noise-ratio is extremely sensitive to the message rates mismatch of two sides, which may be used as a key of bidirectional communication. (general)

The design of multi-core DSP parallel model based on message passing and multi-level pipeline

Science.gov (United States)

Niu, Jingyu; Hu, Jian; He, Wenjing; Meng, Fanrong; Li, Chuanrong

2017-10-01

Currently, the design of embedded signal processing system is often based on a specific application, but this idea is not conducive to the rapid development of signal processing technology. In this paper, a parallel processing model architecture based on multi-core DSP platform is designed, and it is mainly suitable for the complex algorithms which are composed of different modules. This model combines the ideas of multi-level pipeline parallelism and message passing, and summarizes the advantages of the mainstream model of multi-core DSP (the Master-Slave model and the Data Flow model), so that it has better performance. This paper uses three-dimensional image generation algorithm to validate the efficiency of the proposed model by comparing with the effectiveness of the Master-Slave and the Data Flow model.

Using Partial Reconfiguration and Message Passing to Enable FPGA-Based Generic Computing Platforms

Directory of Open Access Journals (Sweden)

Manuel Saldaña

2012-01-01

Full Text Available Partial reconfiguration (PR is an FPGA feature that allows the modification of certain parts of an FPGA while the rest of the system continues to operate without disruption. This distinctive characteristic of FPGAs has many potential benefits but also challenges. The lack of good CAD tools and the deep hardware knowledge requirement result in a hard-to-use feature. In this paper, the new partition-based Xilinx PR flow is used to incorporate PR within our MPI-based message-passing framework to allow hardware designers to create template bitstreams, which are predesigned, prerouted, generic bitstreams that can be reused for multiple applications. As an example of the generality of this approach, four different applications that use the same template bitstream are run consecutively, with a PR operation performed at the beginning of each application to instantiate the desired application engine. We demonstrate a simplified, reusable, high-level, and portable PR interface for X86-FPGA hybrid machines. PR issues such as local resets of reconfigurable modules and context saving and restoring are addressed in this paper followed by some examples and preliminary PR overhead measurements.

Extension of Pairwise Broadcast Clock Synchronization for Multicluster Sensor Networks

Directory of Open Access Journals (Sweden)

Bruce W. Suter

2008-01-01

Full Text Available Time synchronization is crucial for wireless sensor networks (WSNs in performing a number of fundamental operations such as data coordination, power management, security, and localization. The Pairwise Broadcast Synchronization (PBS protocol was recently proposed to minimize the number of timing messages required for global network synchronization, which enables the design of highly energy-efficient WSNs. However, PBS requires all nodes in the network to lie within the communication ranges of two leader nodes, a condition which might not be available in some applications. This paper proposes an extension of PBS to the more general class of sensor networks. Based on the hierarchical structure of the network, an energy-efficient pair selection algorithm is proposed to select the best pairwise synchronization sequence to reduce the overall energy consumption. It is shown that in a multicluster networking environment, PBS requires a far less number of timing messages than other well-known synchronization protocols and incurs no loss in synchronization accuracy. Moreover, the proposed scheme presents significant energy savings for densely deployed WSNs.

Why pass on viral messages? Because they connect emotionally

NARCIS (Netherlands)

Dobele, A.; Lindgreen, A.; Beverland, M.; Vanhamme, J.; Wijk, van R.

2007-01-01

In this article, we identify that successful viral marketing campaigns trigger an emotional response in recipients. Working under this premise, we examine the effects of viral messages containing the six primary emotions (surprise, joy, sadness, anger, fear, and disgust) on recipients' emotional

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

Science.gov (United States)

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

2015-05-01

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

Fault-Tolerant Self-Stabilizing Distributed Clock Synchronization Protocol for Arbitrary Digraphs

Science.gov (United States)

Malekpour, Mahyar R. (Inventor)

2014-01-01

A self-stabilizing network in the form of an arbitrary, non-partitioned digraph includes K nodes having a synchronizer executing a protocol. K-1 monitors of each node may receive a Sync message transmitted from a directly connected node. When the Sync message is received, the logical clock value for the receiving node is set to between 0 and a communication latency value (gamma) if the clock value is less than a minimum event-response delay (D). A new Sync message is also transmitted to any directly connected nodes if the clock value is greater than or equal to both D and a graph threshold (T(sub S)). When the Sync message is not received the synchronizer increments the clock value if the clock value is less than a resynchronization period (P), and resets the clock value and transmits a new Sync message to all directly connected nodes when the clock value equals or exceeds P.

Communicating via robust synchronization of chaotic lasers

International Nuclear Information System (INIS)

Lopez-Gutierrez, R.M.; Posadas-Castillo, C.; Lopez-Mancilla, D.; Cruz-Hernandez, C.

2009-01-01

In this paper, the robust synchronization problem for coupled chaotic Nd:YAG lasers is addressed. We resort to complex systems theory to achieve chaos synchronization. Based on stability theory, it is shown that the state trajectories of the perturbed error synchronization are ultimately bounded, provided the unperturbed synchronization error system is exponentially stable, and some conditions on the bounds of the perturbation terms are satisfied. So that, encoding, transmission, and decoding in chaotic optical communications are presented. We analyze the transmission and recovery of encrypted information when parameter mismatches are considered. Computer simulations are provided to show the effectiveness of this robustness synchronization property, we present the encrypted transmission of image messages, and we show that, the transmitted image is faithfully recovered.

Communicating via robust synchronization of chaotic lasers

Energy Technology Data Exchange (ETDEWEB)

Lopez-Gutierrez, R.M. [Engineering Faculty, Baja California Autonomous University (UABC), Km. 103 Carret. Tij-Ens., 22860 Ensenada, B.C. (Mexico); Posadas-Castillo, C. [Engineering Faculty, Baja California Autonomous University (UABC), Km. 103 Carret. Tij-Ens., 22860 Ensenada, B.C. (Mexico); FIME, Autonomous University of Nuevo Leon (UANL), Pedro de Alba, S.N., Cd. Universitaria, San Nicolas de los Garza, NL (Mexico); Lopez-Mancilla, D. [Departamento de Ciencias Exactas y Tecnologicas, Centro Universitario de los Lagos, Universidad de Guadalajara (CULagos-UdeG), Enrique Diaz de Leon s/n, 47460 Lagos de Moreno, Jal. (Mexico); Cruz-Hernandez, C. [Electronics and Telecommunications Department, Scientific Research and Advanced Studies of Ensenada (CICESE), Km. 107 Carret. Tij-Ens., 22860 Ensenada, B.C. (Mexico)], E-mail: ccruz@cicese.mx

2009-10-15

In this paper, the robust synchronization problem for coupled chaotic Nd:YAG lasers is addressed. We resort to complex systems theory to achieve chaos synchronization. Based on stability theory, it is shown that the state trajectories of the perturbed error synchronization are ultimately bounded, provided the unperturbed synchronization error system is exponentially stable, and some conditions on the bounds of the perturbation terms are satisfied. So that, encoding, transmission, and decoding in chaotic optical communications are presented. We analyze the transmission and recovery of encrypted information when parameter mismatches are considered. Computer simulations are provided to show the effectiveness of this robustness synchronization property, we present the encrypted transmission of image messages, and we show that, the transmitted image is faithfully recovered.

Extracting messages masked by chaos

International Nuclear Information System (INIS)

Perez, G.; Cerdeira, H.A.

1995-01-01

We show how to extract messages that are masked by a chaotic signal in a system of two Lorenz oscillators. This mask removal is done for two different modes of transmission, a digital one where a parameter of the sender is switched between two values, and an analog mode, where a small amplitude message is added to the carrier signal. We achieve this without using a second Lorenz oscillator as receiver, and without doing a full reconstruction of the dynamics. This method is robust with respect to transformations that impede the unmasking using a Lorenz receiver, and is not affected by the broad-band noise that is inherent to the synchronization process. We also discuss the limitations of this way of extraction for messages in high frequency bands. (author). 12 refs, 4 figs

On the theoretical gap between synchronous and asynchronous MPC protocols

DEFF Research Database (Denmark)

Beerliová-Trubíniová, Zuzana; Hirt, Martin; Nielsen, Jesper Buus

2010-01-01

that in the cryptographic setting (with setup), the sole reason for it is the distribution of inputs: given an oracle for input distribution, cryptographically-secure asynchronous MPC is possible with the very same condition as synchronous MPC, namely t ..., we show that such an input-distribution oracle can be reduced to an oracle that allows each party to synchronously broadcast one single message. This means that when one single round of synchronous broadcast is available, then asynchronous MPC is possible at the same condition as synchronous MPC...

Mixed synchronization in chaotic oscillators using scalar coupling

Energy Technology Data Exchange (ETDEWEB)

Bhowmick, Sourav K.; Hens, Chittaranjan [CSIR – Indian Institute of Chemical Biology, Jadavpur, Kolkata 700032 (India); Ghosh, Dibakar, E-mail: drghosh_math@yahoo.co.in [Department of Mathematics, University of Kalyani, West Bengal 741235 (India); Dana, Syamal K. [CSIR – Indian Institute of Chemical Biology, Jadavpur, Kolkata 700032 (India)

2012-07-23

We report experimental evidence of mixed synchronization in two unidirectionally coupled chaotic oscillators using a scalar coupling. In this synchronization regime, some of the state variables may be in complete synchronization while others may be in anti-synchronization state. We extended the theory by using an adaptive controller with an updating law based on Lyapunov function stability to include parameter fluctuation. Using the scheme, we implemented a cryptographic encoding for digital signal through parameter modulation. -- Highlights: ► We provided experimental evidence of the mixed synchronization scheme while other methods are mostly theoretical nature. ► We numerically studied adaptive mixed synchronization when the parameters are not completely known using scalar coupling. ► We proposed a secure communication system where three digital messages are transmitted using parameter modulation.

Communication strategies for angular domain decomposition of transport calculations on message passing multiprocessors

International Nuclear Information System (INIS)

Azmy, Y.Y.

1997-01-01

The effect of three communication schemes for solving Arbitrarily High Order Transport (AHOT) methods of the Nodal type on parallel performance is examined via direct measurements and performance models. The target architecture in this study is Oak Ridge National Laboratory's 128 node Paragon XP/S 5 computer and the parallelization is based on the Parallel Virtual Machine (PVM) library. However, the conclusions reached can be easily generalized to a large class of message passing platforms and communication software. The three schemes considered here are: (1) PVM's global operations (broadcast and reduce) which utilizes the Paragon's native corresponding operations based on a spanning tree routing; (2) the Bucket algorithm wherein the angular domain decomposition of the mesh sweep is complemented with a spatial domain decomposition of the accumulation process of the scalar flux from the angular flux and the convergence test; (3) a distributed memory version of the Bucket algorithm that pushes the spatial domain decomposition one step farther by actually distributing the fixed source and flux iterates over the memories of the participating processes. Their conclusion is that the Bucket algorithm is the most efficient of the three if all participating processes have sufficient memories to hold the entire problem arrays. Otherwise, the third scheme becomes necessary at an additional cost to speedup and parallel efficiency that is quantifiable via the parallel performance model

Reactors: A data-oriented synchronous/asynchronous programming model for distributed applications

DEFF Research Database (Denmark)

Field, John; Marinescu, Maria-Cristina; Stefansen, Christian Oskar Erik

2009-01-01

of messages. Similarly, the interface to a reactor is simply its state, rather than a collection of message channels, ports, or methods. One novel feature of our model is the ability to compose behaviors both synchronously and asynchronously. Also, our use of Datalog-style rules allows aspect-like composition...

Dreams: a framework for distributed synchronous coordination

NARCIS (Netherlands)

Proença, J.; Clarke, D.; Vink, de E.P.; Arbab, F.

2012-01-01

Synchronous coordination systems, such as Reo, exchange data via indivisible actions, while distributed systems are typically asynchronous and assume that messages can be delayed or get lost. To combine these seemingly contradictory notions, we introduce the Dreams framework. Coordination patterns

Detecting and Preventing Sybil Attacks in Wireless Sensor Networks Using Message Authentication and Passing Method.

Science.gov (United States)

Dhamodharan, Udaya Suriya Raj Kumar; Vayanaperumal, Rajamani

2015-01-01

Wireless sensor networks are highly indispensable for securing network protection. Highly critical attacks of various kinds have been documented in wireless sensor network till now by many researchers. The Sybil attack is a massive destructive attack against the sensor network where numerous genuine identities with forged identities are used for getting an illegal entry into a network. Discerning the Sybil attack, sinkhole, and wormhole attack while multicasting is a tremendous job in wireless sensor network. Basically a Sybil attack means a node which pretends its identity to other nodes. Communication to an illegal node results in data loss and becomes dangerous in the network. The existing method Random Password Comparison has only a scheme which just verifies the node identities by analyzing the neighbors. A survey was done on a Sybil attack with the objective of resolving this problem. The survey has proposed a combined CAM-PVM (compare and match-position verification method) with MAP (message authentication and passing) for detecting, eliminating, and eventually preventing the entry of Sybil nodes in the network. We propose a scheme of assuring security for wireless sensor network, to deal with attacks of these kinds in unicasting and multicasting.

Detecting and Preventing Sybil Attacks in Wireless Sensor Networks Using Message Authentication and Passing Method

Directory of Open Access Journals (Sweden)

Udaya Suriya Raj Kumar Dhamodharan

2015-01-01

Full Text Available Wireless sensor networks are highly indispensable for securing network protection. Highly critical attacks of various kinds have been documented in wireless sensor network till now by many researchers. The Sybil attack is a massive destructive attack against the sensor network where numerous genuine identities with forged identities are used for getting an illegal entry into a network. Discerning the Sybil attack, sinkhole, and wormhole attack while multicasting is a tremendous job in wireless sensor network. Basically a Sybil attack means a node which pretends its identity to other nodes. Communication to an illegal node results in data loss and becomes dangerous in the network. The existing method Random Password Comparison has only a scheme which just verifies the node identities by analyzing the neighbors. A survey was done on a Sybil attack with the objective of resolving this problem. The survey has proposed a combined CAM-PVM (compare and match-position verification method with MAP (message authentication and passing for detecting, eliminating, and eventually preventing the entry of Sybil nodes in the network. We propose a scheme of assuring security for wireless sensor network, to deal with attacks of these kinds in unicasting and multicasting.

A chimeric path to neuronal synchronization

Science.gov (United States)

Essaki Arumugam, Easwara Moorthy; Spano, Mark L.

2015-01-01

Synchronization of neuronal activity is associated with neurological disorders such as epilepsy. This process of neuronal synchronization is not fully understood. To further our understanding, we have experimentally studied the progression of this synchronization from normal neuronal firing to full synchronization. We implemented nine FitzHugh-Nagumo neurons (a simplified Hodgkin-Huxley model) via discrete electronics. For different coupling parameters (synaptic strengths), the neurons in the ring were either unsynchronized or completely synchronized when locally coupled in a ring. When a single long-range connection (nonlocal coupling) was introduced, an intermediate state known as a chimera appeared. The results indicate that (1) epilepsy is likely not only a dynamical disease but also a topological disease, strongly tied to the connectivity of the underlying network of neurons, and (2) the synchronization process in epilepsy may not be an "all or none" phenomenon, but can pass through an intermediate stage (chimera).

A chimeric path to neuronal synchronization

Energy Technology Data Exchange (ETDEWEB)

Essaki Arumugam, Easwara Moorthy; Spano, Mark L. [School of Biological and Health Systems Engineering, Arizona State University, Tempe, Arizona 85287-9709 (United States)

2015-01-15

Synchronization of neuronal activity is associated with neurological disorders such as epilepsy. This process of neuronal synchronization is not fully understood. To further our understanding, we have experimentally studied the progression of this synchronization from normal neuronal firing to full synchronization. We implemented nine FitzHugh-Nagumo neurons (a simplified Hodgkin-Huxley model) via discrete electronics. For different coupling parameters (synaptic strengths), the neurons in the ring were either unsynchronized or completely synchronized when locally coupled in a ring. When a single long-range connection (nonlocal coupling) was introduced, an intermediate state known as a chimera appeared. The results indicate that (1) epilepsy is likely not only a dynamical disease but also a topological disease, strongly tied to the connectivity of the underlying network of neurons, and (2) the synchronization process in epilepsy may not be an “all or none” phenomenon, but can pass through an intermediate stage (chimera)

A chimeric path to neuronal synchronization

International Nuclear Information System (INIS)

Essaki Arumugam, Easwara Moorthy; Spano, Mark L.

2015-01-01

Synchronization of neuronal activity is associated with neurological disorders such as epilepsy. This process of neuronal synchronization is not fully understood. To further our understanding, we have experimentally studied the progression of this synchronization from normal neuronal firing to full synchronization. We implemented nine FitzHugh-Nagumo neurons (a simplified Hodgkin-Huxley model) via discrete electronics. For different coupling parameters (synaptic strengths), the neurons in the ring were either unsynchronized or completely synchronized when locally coupled in a ring. When a single long-range connection (nonlocal coupling) was introduced, an intermediate state known as a chimera appeared. The results indicate that (1) epilepsy is likely not only a dynamical disease but also a topological disease, strongly tied to the connectivity of the underlying network of neurons, and (2) the synchronization process in epilepsy may not be an “all or none” phenomenon, but can pass through an intermediate stage (chimera)

A System for Exchanging Control and Status Messages in the NOvA Data Acquisition

International Nuclear Information System (INIS)

Biery, K.A.; Cooper, R.G.; Foulkes, S.C.; Guglielmo, G.M.; Piccoli, L.P.; Votava, M.E.V.; Fermilab

2007-01-01

In preparation for NOvA, a future neutrino experiment at Fermilab, we are developing a system for passing control and status messages in the data acquisition system. The DAQ system will consist of applications running on approximately 450 nodes. The message passing system will use a publish-subscribe model and will provide support for sending messages and receiving the associated replies. Additional features of the system include a layered architecture with custom APIs tailored to the needs of a DAQ system, the use of an open source messaging system for handling the reliable delivery of messages, the ability to send broadcasts to groups of applications, and APIs in Java, C++, and Python. Our choice for the open source system to deliver messages is EPICS. We will discuss the architecture of the system, our experience with EPICS, and preliminary test results

A System for Exchanging Control and Status Messages in the NOvA Data Acquisition

Energy Technology Data Exchange (ETDEWEB)

Biery, K.A.; Cooper, R.G.; Foulkes, S.C.; Guglielmo, G.M.; Piccoli, L.P.; Votava, M.E.V.; /Fermilab

2007-04-01

In preparation for NOvA, a future neutrino experiment at Fermilab, we are developing a system for passing control and status messages in the data acquisition system. The DAQ system will consist of applications running on approximately 450 nodes. The message passing system will use a publish-subscribe model and will provide support for sending messages and receiving the associated replies. Additional features of the system include a layered architecture with custom APIs tailored to the needs of a DAQ system, the use of an open source messaging system for handling the reliable delivery of messages, the ability to send broadcasts to groups of applications, and APIs in Java, C++, and Python. Our choice for the open source system to deliver messages is EPICS. We will discuss the architecture of the system, our experience with EPICS, and preliminary test results.

A collaborative processes synchronization method with regard to system crashes and network failures

NARCIS (Netherlands)

Wang, Lei; Wombacher, Andreas; Ferreira Pires, Luis; van Sinderen, Marten J.; Chi, Chihung

2014-01-01

Processes can synchronize their states by exchanging messages. System crashes and network failures may cause message loss, so that state changes of a process may remain unnoticed by its partner processes, resulting in state inconsistency or deadlocks. In this paper we define a method to transform a

The synchronization of loosely coupled motion control systems

Energy Technology Data Exchange (ETDEWEB)

Tuominen, P. [VTT Automation, Tampere (Finland). Machine Automation

1996-12-31

The aim of this thesis is to create an easily implemented, effective, dynamically schedulable flow control method, and to show how the methods introduced can be analysed using fixed priority scheduling. One of the most important problems in a distributed system is the delay and variation of it (the jitter) caused by a serial based network, especially when media load is relatively high. This thesis has looked for possibilities to implement a deterministic motion control system which can also operate with high media loads. The problem of end-to-end delay in distributed control systems has been addressed. The most promising ones are based on the two window concept, where critical messages are transmitted in the statically scheduled part of window while other, non-critical messages are transmitted in the remaining part. The concept of the chained link is introduced and it is shown how the latency time of a certain set of messages can be controlled. This thesis has introduced the detailed characteristics of this easy-to-assemble chain which is simpler than time or sync-message based methods used commercially. One benefit is that only those nodes needing synchronization must support synchronization tasks. Other nodes are exempt from supporting unnecessary functions, making system programming easier. The chain can be scheduled dynamically as one long message. The concept of a CAN based producer-consumer method, a statical scheduling method which can be used with a bus-master has been introduced. A hydraulic mobile is used as a practical example for analysing and comparing the introduced distribution and flow control methods

Actors with Multi-Headed Message Receive Patterns

DEFF Research Database (Denmark)

Sulzmann, Martin; Lam, Edmund Soon Lee; Van Weert, Peter

2008-01-01

style actors with receive clauses containing multi-headed message patterns. Patterns may be non-linear and constrained by guards. We provide a number of examples to show the usefulness of the extension. We also explore the design space for multi-headed message matching semantics, for example first-match......The actor model provides high-level concurrency abstractions to coordinate simultaneous computations by message passing. Languages implementing the actor model such as Erlang commonly only support single-headed pattern matching over received messages. We propose and design an extension of Erlang...... and rule priority-match semantics. The various semantics are inspired by the multi-set constraint matching semantics found in Constraint Handling Rules. This provides us with a formal model to study actors with multi-headed message receive patterns. The system can be implemented efficiently and we have...

Synchronization in a PLC/VAX-based control and data-acquisition system of a nuclear-fusion experiment

International Nuclear Information System (INIS)

Schmidt, V.; Flor, G.; Hemming, O.N.; Luchetta, A.; Manduchi, G.; Vitturi, S.

1990-01-01

This paper describes the concept and implementation details of the synchronization mechanisms used in the control and data-acquisition system of the RFX (Reversed-Field Experiment) nuclear-fusion experimental device, at present under construction in Padova, Italy, within the framework of the co-ordinated nuclear-fusion research programme of the European Communities. The system employs industrial PLCs for the 'slow' control and monitoring functions, and a VAX-based CAMAC for the 'fast' functions of trigger-signal generation and data acquisition during the experiment pulses. All subsystems communicate via Ethernet, using compatible software protocols. The operational sequence of the complete system is governed by a single state machine implemented on a PLC-based supervisor system. Equivalent 'slave' state machines are implemented on all other subsystems (PLC- and VAX-based). These state machines are synchronized by means of the exchange of messages via Ethernet. This paper deals in detail with the following components which are involved in system synchronization: The Message Exchange System which implements the system-wide exchange of short messages; the Scheduler programs which implement the state machine on the various computing nodes, and which make use of the Message Exchange System. (orig.)

Synchronization of time-delayed systems with chaotic modulation and cryptography

International Nuclear Information System (INIS)

Banerjee, Santo

2009-01-01

This paper presents a method of synchronization between two time-delayed systems where the delay times are modulated by a common chaotic signal of the driving system. The technique is well applied to two identical autonomous continuous-time-delayed systems with numerical simulations. Finally, a new method of encryption is generated for digital messages. This method is illustrated with two different encryption processes for text as well as picture messages.

Synchronization of the chaotic secure communication system with output state delay

International Nuclear Information System (INIS)

Changchien, S.-K.; Huang, C.-K.; Nien, H.-H.; Shieh, H.-W.

2009-01-01

In this paper, we utilize a proper Lyapunov function and Lyapunov theorem, combined with LMIs method, in order to design a controller L, which ensures the synchronization between the transmission and the reception ends of the chaotic secure communication system with time-delay of output state. Meanwhile, for the purpose of increasing communication security, we encrypt and decrypt the original to-be-transmitted message with the techniques of n-shift cipher and public key. The result of simulation shows that the proposed method is able to synchronize the transmission and the reception ends of the system, and moreover, to recover the original message at the reception end. Therefore, the method proposed in this paper is effective and feasible to apply in the chaotic secure communication system.

An Energy-efficient Clock Synchronization Protocol for Wireless Sensor Networks

OpenAIRE

Albu, Roxana; Labit, Yann; Thierry, Gayraud; Pascal, Berthou

2010-01-01

5p.; International audience; The behavior of Wireless Sensor Networks (WSN) is nowadays widely analyzed. One of the most important issues is related to their energy consumption, as this has a major impact on the network lifetime. Another important application requirement is to ensure data sensing synchronization, which leads to additional energy consumption as a high number of messages is sent and received at each node. Our proposal consists in implementing a combined synchronization protocol...

Efficient Distribution of Triggered Synchronous Block Diagrams

Science.gov (United States)

2011-10-21

latest input data it reads fromW ∗. IfR ∗ receives a message fromW ∗ whose fresh-bit is false, meaning that R∗ has already read the latest output data...assumptions on clock synchronization. This has the advantage of providing implementations that are robust to various types of timing uncertainties such as

Protecting Clock Synchronization: Adversary Detection through Network Monitoring

Directory of Open Access Journals (Sweden)

Elena Lisova

2016-01-01

Full Text Available Nowadays, industrial networks are often used for safety-critical applications with real-time requirements. Such applications usually have a time-triggered nature with message scheduling as a core property. Scheduling requires nodes to share the same notion of time, that is, to be synchronized. Therefore, clock synchronization is a fundamental asset in real-time networks. However, since typical standards for clock synchronization, for example, IEEE 1588, do not provide the required level of security, it raises the question of clock synchronization protection. In this paper, we identify a way to break synchronization based on the IEEE 1588 standard, by conducting a man-in-the-middle (MIM attack followed by a delay attack. A MIM attack can be accomplished through, for example, Address Resolution Protocol (ARP poisoning. Using the AVISPA tool, we evaluate the potential to perform a delay attack using ARP poisoning and analyze its consequences showing both that the attack can, indeed, break clock synchronization and that some design choices, such as a relaxed synchronization condition mode, delay bounding, and using knowledge of environmental conditions, can make the network more robust/resilient against these kinds of attacks. Lastly, a Configuration Agent is proposed to monitor and detect anomalies introduced by an adversary performing attacks targeting clock synchronization.

Traveling-wave synchronous coil gun

International Nuclear Information System (INIS)

Elliott, D.G.

1991-01-01

This paper reports on a traveling-wave synchronous coil gun which permits independent adjustment of the magnetic field and armature current for high velocity at low armature mass fraction. Magnetic field energy is transferred from the rear of the wave to the front without passing through the power supply. Elaborate switching is required

Hybrid electronic/optical synchronized chaos communication system.

Science.gov (United States)

Toomey, J P; Kane, D M; Davidović, A; Huntington, E H

2009-04-27

A hybrid electronic/optical system for synchronizing a chaotic receiver to a chaotic transmitter has been demonstrated. The chaotic signal is generated electronically and injected, in addition to a constant bias current, to a semiconductor laser to produce an optical carrier for transmission. The optical chaotic carrier is photodetected to regenerate an electronic signal for synchronization in a matched electronic receiver The system has been successfully used for the transmission and recovery of a chaos masked message that is added to the chaotic optical carrier. Past demonstrations of synchronized chaos based, secure communication systems have used either an electronic chaotic carrier or an optical chaotic carrier (such as the chaotic output of various nonlinear laser systems). This is the first electronic/optical hybrid system to be demonstrated. We call this generation of a chaotic optical carrier by electronic injection.

An FPGA Based Multiprocessing CPU for Beam Synchronous Timing in CERN's SPS and LHC

CERN Document Server

Ballester, F J; Gras, J J; Lewis, J; Savioz, J J; Serrano, J

2003-01-01

The Beam Synchronous Timing system (BST) will be used around the LHC and its injector, the SPS, to broadcast timing meassages and synchronize actions with the beam in different receivers. To achieve beam synchronization, the BST Master card encodes messages using the bunch clock, with a nominal value of 40.079 MHz for the LHC. These messages are produced by a set of tasks every revolution period, which is every 89 us for the LHC and every 23 us for the SPS, therefore imposing a hard real-time constraint on the system. To achieve determinism, the BST Master uses a dedicated CPU inside its main Field Programmable Gate Array (FPGA) featuring zero-delay hardware task switching and a reduced instruction set. This paper describes the BST Master card, stressing the main FPGA design, as well as the associated software, including the LynxOS driver and the tailor-made assembler.

Hybrid synchronization of two independent chaotic systems on ...

Indian Academy of Sciences (India)

The real network nodes are always interfered by other messages. So, how to realize the hybrid synchronization of two independent chaotic systems based on the complex network is very important. To solve this problem, two other problems should be considered. One is how the same network node of the complex network ...

Distributed synchronization for Beyond 4G Indoor Femtocells

DEFF Research Database (Denmark)

Berardinelli, Gilberto; Tavares, Fernando Menezes Leitão; Mahmood, Nurul Huda

2013-01-01

strict time synchronization between the cells. This paper deals with distributed runtime synchronization for Beyond 4G femtocells. A simple random scheduling solution for the clock distribution messages is proposed, as well as different clock update mechanisms. Simulation results for a dense cell...... scenario with two stripes of apartments show that a ‘multiplicative clock update’ exhibits an initial large time divergence among neighbor cells, but is able to achieve a lower long-term error floor than ‘additive clock update’. Practical implications of the residual time misalignment on the Beyond 4G...... system design are also addressed....

Hardware-assisted software clock synchronization for homogeneous distributed systems

Science.gov (United States)

Ramanathan, P.; Kandlur, Dilip D.; Shin, Kang G.

1990-01-01

A clock synchronization scheme that strikes a balance between hardware and software solutions is proposed. The proposed is a software algorithm that uses minimal additional hardware to achieve reasonably tight synchronization. Unlike other software solutions, the guaranteed worst-case skews can be made insensitive to the maximum variation of message transit delay in the system. The scheme is particularly suitable for large partially connected distributed systems with topologies that support simple point-to-point broadcast algorithms. Examples of such topologies include the hypercube and the mesh interconnection structures.

Couriers in the Inca Empire: Getting Your Message Across. [Lesson Plan].

Science.gov (United States)

2002

This lesson shows how the Inca communicated across the vast stretches of their mountain realm, the largest empire of the pre-industrial world. The lesson explains how couriers carried messages along mountain-ridge roads, up and down stone steps, and over chasm-spanning footbridges. It states that couriers could pass a message from Quito (Ecuador)…

An Overview of a Class of Clock Synchronization Algorithms for Wireless Sensor Networks: A Statistical Signal Processing Perspective

Directory of Open Access Journals (Sweden)

Xu Wang

2015-08-01

Full Text Available Recently, wireless sensor networks (WSNs have drawn great interest due to their outstanding monitoring and management potential in medical, environmental and industrial applications. Most of the applications that employ WSNs demand all of the sensor nodes to run on a common time scale, a requirement that highlights the importance of clock synchronization. The clock synchronization problem in WSNs is inherently related to parameter estimation. The accuracy of clock synchronization algorithms depends essentially on the statistical properties of the parameter estimation algorithms. Recently, studies dedicated to the estimation of synchronization parameters, such as clock offset and skew, have begun to emerge in the literature. The aim of this article is to provide an overview of the state-of-the-art clock synchronization algorithms for WSNs from a statistical signal processing point of view. This article focuses on describing the key features of the class of clock synchronization algorithms that exploit the traditional two-way message (signal exchange mechanism. Upon introducing the two-way message exchange mechanism, the main clock offset estimation algorithms for pairwise synchronization of sensor nodes are first reviewed, and their performance is compared. The class of fully-distributed clock offset estimation algorithms for network-wide synchronization is then surveyed. The paper concludes with a list of open research problems pertaining to clock synchronization of WSNs.

Synchronization resources in heterogeneous environments: Time-sharing, real-time and Java

International Nuclear Information System (INIS)

Pereira, A.; Vega, J.; Pacios, L.; Sanchez, E.; Portas, A.

2006-01-01

The asynchronous event distribution system (AEDS) was built to provide synchronization resources within the TJ-II local area network. It is a software system developed to add 'soft synchronization' capabilities to the TJ-II data acquisition, control and analysis environments. 'Soft synchronization' signifies that AEDS is not a real-time system. In fact, AEDS is based on TCP/IP over ETHERNET networks. However, its response time is adequate for practical purposes when synchronization requirements can support some delay between event dispatch and message reception. Event broadcasters (or synchronization servers in AEDS terminology) are Windows computers. Destination computers (or synchronization clients) were also Windows machines in the first version of AEDS. However, this fact imposed a very important limitation on synchronization capabilities. To overcome this situation, synchronization clients for different environments have been added to AEDS: for time-sharing operating systems (Unix and Linux), real-time operating systems (OS-9 and VxWorks) and Java applications. These environments have different synchronization primitives, requiring different approaches to provide the required uniform functionality. This has been achieved with POSIX thread library synchronization primitives (mutex and condition variables) on Unix/Linux systems, IPC mechanisms for concurrent processes on OS-9 and VxWorks real-time operating systems, and 'synchronized-wait/notify' primitives on Java virtual machines

Firefly Clock Synchronization in an 802.15.4 Wireless Network

Directory of Open Access Journals (Sweden)

Elmenreich Wilfried

2009-01-01

Full Text Available This paper describes the design and implementation of a distributed self-stabilizing clock synchronization algorithm based on the biological example of Asian Fireflies. Huge swarms of these fireflies use the principle of pulse coupled oscillators in order to synchronously emit light flashes to attract mating partners. When applying this algorithm to real sensor networks, typically, nodes cannot receive messages while transmitting, which prevents the networked nodes from reaching synchronization. In order to counteract this deafness problem, we adopt a variant of the Reachback Firefly Algorithm to distribute the timing of light flashes in a given time window without affecting the quality of the synchronization. A case study implemented on 802.15.4 Zigbee nodes presents the application of this approach for a time-triggered communication scheduling and coordinated duty cycling in order to enhance the battery lifetime of the nodes.

Radio nuclide cardiac examination with 'self-synchronization'

International Nuclear Information System (INIS)

Komatani, Akio; Takamiya, Makoto; Takahashi, Kazuei; Yamaguchi, Kohichi

1981-01-01

R wave of electrocardiogram (ECG) has been usually employed for the synchronization at the radionuclide cardiac examination. But, we tried to adopt the extremums of the left ventricular time activity curve as time reference points for the synchronization instead of ECG gating in the first pass study. There could be selected end dystolic (ED) and/or end systolic (ES) points as the time reference for the synchronization, and clear cine mode display could be obtained compared with ECG gating method. Using this processing, reconstruction of the frame data could be executed within 2.5 minutes, and cine mode display required only 8 minutes. Not only unnecessity of patching ECG electrodes to the patients, but rapid data aquisition and processing are very usefull for daily clinical work. (author)

Synchronization resources in heterogeneous environments: Time-sharing, real-time and Java

Energy Technology Data Exchange (ETDEWEB)

Pereira, A. [Asociacion EURATOM/CIEMAT para Fusion, CIEMAT Edificio 66, Avda. Complutense, 22, 28040 Madrid (Spain)]. E-mail: augusto.pereira@ciemat.es; Vega, J. [Asociacion EURATOM/CIEMAT para Fusion, CIEMAT Edificio 66, Avda. Complutense, 22, 28040 Madrid (Spain); Pacios, L. [Asociacion EURATOM/CIEMAT para Fusion, CIEMAT Edificio 66, Avda. Complutense, 22, 28040 Madrid (Spain); Sanchez, E. [Asociacion EURATOM/CIEMAT para Fusion, CIEMAT Edificio 66, Avda. Complutense, 22, 28040 Madrid (Spain); Portas, A. [Asociacion EURATOM/CIEMAT para Fusion, CIEMAT Edificio 66, Avda. Complutense, 22, 28040 Madrid (Spain)

2006-07-15

The asynchronous event distribution system (AEDS) was built to provide synchronization resources within the TJ-II local area network. It is a software system developed to add 'soft synchronization' capabilities to the TJ-II data acquisition, control and analysis environments. 'Soft synchronization' signifies that AEDS is not a real-time system. In fact, AEDS is based on TCP/IP over ETHERNET networks. However, its response time is adequate for practical purposes when synchronization requirements can support some delay between event dispatch and message reception. Event broadcasters (or synchronization servers in AEDS terminology) are Windows computers. Destination computers (or synchronization clients) were also Windows machines in the first version of AEDS. However, this fact imposed a very important limitation on synchronization capabilities. To overcome this situation, synchronization clients for different environments have been added to AEDS: for time-sharing operating systems (Unix and Linux), real-time operating systems (OS-9 and VxWorks) and Java applications. These environments have different synchronization primitives, requiring different approaches to provide the required uniform functionality. This has been achieved with POSIX thread library synchronization primitives (mutex and condition variables) on Unix/Linux systems, IPC mechanisms for concurrent processes on OS-9 and VxWorks real-time operating systems, and 'synchronized-wait/notify' primitives on Java virtual machines.

Three-pass protocol scheme for bitmap image security by using vernam cipher algorithm

Science.gov (United States)

Rachmawati, D.; Budiman, M. A.; Aulya, L.

2018-02-01

Confidentiality, integrity, and efficiency are the crucial aspects of data security. Among the other digital data, image data is too prone to abuse of operation like duplication, modification, etc. There are some data security techniques, one of them is cryptography. The security of Vernam Cipher cryptography algorithm is very dependent on the key exchange process. If the key is leaked, security of this algorithm will collapse. Therefore, a method that minimizes key leakage during the exchange of messages is required. The method which is used, is known as Three-Pass Protocol. This protocol enables message delivery process without the key exchange. Therefore, the sending messages process can reach the receiver safely without fear of key leakage. The system is built by using Java programming language. The materials which are used for system testing are image in size 200×200 pixel, 300×300 pixel, 500×500 pixel, 800×800 pixel and 1000×1000 pixel. The result of experiments showed that Vernam Cipher algorithm in Three-Pass Protocol scheme could restore the original image.

Adaptive modified function projective synchronization of multiple time-delayed chaotic Rossler system

International Nuclear Information System (INIS)

Sudheer, K. Sebastian; Sabir, M.

2011-01-01

In this Letter we consider modified function projective synchronization of unidirectionally coupled multiple time-delayed Rossler chaotic systems using adaptive controls. Recently, delay differential equations have attracted much attention in the field of nonlinear dynamics. The high complexity of the multiple time-delayed systems can provide a new architecture for enhancing message security in chaos based encryption systems. Adaptive control can be used for synchronization when the parameters of the system are unknown. Based on Lyapunov stability theory, the adaptive control law and the parameter update law are derived to make the state of two chaotic systems are function projective synchronized. Numerical simulations are presented to demonstrate the effectiveness of the proposed adaptive controllers.

What motivates consumers to re-tweet brand content? The impact of information, emotion, and traceability on pass-along behavior

NARCIS (Netherlands)

Araujo, T.; Neijens, P.; Vliegenthart, R.

2015-01-01

How do certain cues influence pass-along behavior (re-Tweeting) of brand messages on Twitter? Analyzing 19,343 global brand messages over a three-year period, the authors of this article found that informational cues were predictors of higher levels of re-Tweeting, particularly product details and

Anticipatory synchronization via low-dimensional filters

International Nuclear Information System (INIS)

Pyragiene, T.; Pyragas, K.

2017-01-01

An anticipatory chaotic synchronization scheme based on a low-order all-pass filter is proposed. The filter is designed as a Padé approximation to the transfer function of an ideal delay line, which is used in a standard Voss scheme. We show that despite its simplicity, the filter works in an anticipatory scheme as well as an ideal delay line. It provides extremely small synchronization error in the whole interval of anticipation time where the anticipatory manifold is stable. The efficacy of our scheme is explained by an analytically solvable model of unidirectionally coupled unstable spirals and confirmed numerically by an example of unidirectionally coupled chaotic Rössler systems. - Highlights: • A new coupling scheme for anticipating chaotic synchronization is proposed. • The scheme consists of a drive system coupled to a low-dimensional filter. • Long-term anticipation is achieved without using time-delay terms. • An analytical treatment estimates the maximum anticipation time. • The method is verified for the Rössler system.

Anticipatory synchronization via low-dimensional filters

Energy Technology Data Exchange (ETDEWEB)

Pyragiene, T., E-mail: tatjana.pyragiene@ftmc.lt; Pyragas, K.

2017-06-15

An anticipatory chaotic synchronization scheme based on a low-order all-pass filter is proposed. The filter is designed as a Padé approximation to the transfer function of an ideal delay line, which is used in a standard Voss scheme. We show that despite its simplicity, the filter works in an anticipatory scheme as well as an ideal delay line. It provides extremely small synchronization error in the whole interval of anticipation time where the anticipatory manifold is stable. The efficacy of our scheme is explained by an analytically solvable model of unidirectionally coupled unstable spirals and confirmed numerically by an example of unidirectionally coupled chaotic Rössler systems. - Highlights: • A new coupling scheme for anticipating chaotic synchronization is proposed. • The scheme consists of a drive system coupled to a low-dimensional filter. • Long-term anticipation is achieved without using time-delay terms. • An analytical treatment estimates the maximum anticipation time. • The method is verified for the Rössler system.

Generation-based memory synchronization in a multiprocessor system with weakly consistent memory accesses

Energy Technology Data Exchange (ETDEWEB)

Ohmacht, Martin

2017-08-15

In a multiprocessor system, a central memory synchronization module coordinates memory synchronization requests responsive to memory access requests in flight, a generation counter, and a reclaim pointer. The central module communicates via point-to-point communication. The module includes a global OR reduce tree for each memory access requesting device, for detecting memory access requests in flight. An interface unit is implemented associated with each processor requesting synchronization. The interface unit includes multiple generation completion detectors. The generation count and reclaim pointer do not pass one another.

Generation-based memory synchronization in a multiprocessor system with weakly consistent memory accesses

Science.gov (United States)

Ohmacht, Martin

2014-09-09

In a multiprocessor system, a central memory synchronization module coordinates memory synchronization requests responsive to memory access requests in flight, a generation counter, and a reclaim pointer. The central module communicates via point-to-point communication. The module includes a global OR reduce tree for each memory access requesting device, for detecting memory access requests in flight. An interface unit is implemented associated with each processor requesting synchronization. The interface unit includes multiple generation completion detectors. The generation count and reclaim pointer do not pass one another.

Event-Driven Messaging for Offline Data Quality Monitoring at ATLAS

CERN Document Server

Onyisi, Peter; The ATLAS collaboration

2015-01-01

During LHC Run 1, the information flow through the offline data quality monitoring in ATLAS relied heavily on chains of processes polling each other's outputs for handshaking purposes. This resulted in a fragile architecture with many possible points of failure and an inability to monitor the overall state of the distributed system. We report on the status of a project undertaken during the LHC shutdown to replace the ad hoc synchronization methods with a uniform message queue system. This enables the use of standard protocols to connect processes on multiple hosts; reliable transmission of messages between possibly unreliable programs; easy monitoring of the information flow; and the removal of inefficient polling-based communication.

Message-passing-interface-based parallel FDTD investigation on the EM scattering from a 1-D rough sea surface using uniaxial perfectly matched layer absorbing boundary.

Science.gov (United States)

Li, J; Guo, L-X; Zeng, H; Han, X-B

2009-06-01

A message-passing-interface (MPI)-based parallel finite-difference time-domain (FDTD) algorithm for the electromagnetic scattering from a 1-D randomly rough sea surface is presented. The uniaxial perfectly matched layer (UPML) medium is adopted for truncation of FDTD lattices, in which the finite-difference equations can be used for the total computation domain by properly choosing the uniaxial parameters. This makes the parallel FDTD algorithm easier to implement. The parallel performance with different processors is illustrated for one sea surface realization, and the computation time of the parallel FDTD algorithm is dramatically reduced compared to a single-process implementation. Finally, some numerical results are shown, including the backscattering characteristics of sea surface for different polarization and the bistatic scattering from a sea surface with large incident angle and large wind speed.

Parallel object-oriented specification language

NARCIS (Netherlands)

Florescu, O.; Voeten, J.P.M.; Theelen, B.D.; Geilen, M.C.W.; Corporaal, H.; Burns, Alan

2008-01-01

The Parallel Object-Oriented Specification Language (POOSL) is an expressive modelling language for hardware/software systems [10]. It was originally defined in [7] as an object-oriented extension of process algebra CCS [6], supporting (conditional) synchronous message passing between

Technical Evaluation Reports 15. Chat and Instant Messaging Systems (synchronous: Report 3/ 3

Directory of Open Access Journals (Sweden)

Brian Ludwig

2002-10-01

Full Text Available [Previous reviews of chat and IM systems are presented in Reports 6 and 14 in this series.]A further set of four text-based instant messaging (IM products was evaluated: AT&T Anywhere, Parachat, Sonork, and Yahoo Messenger, all available at no cost. Yahoo Messenger was judged to be the most effective of the three products for use by distance education (DE teachers and students, being compatible with most common operating systems and accommodating up to 50 chat room participants. Yahoo Messenger also possesses integrated audio and video capabilities. AT&T Anywhere is an efficient product, which supports Windows-based operating systems only. Parachat (Basic version is a basic, browser accessed chat board without instant messaging (IM capabilities.

Space Network Time Distribution and Synchronization Protocol Development for Mars Proximity Link

Science.gov (United States)

Woo, Simon S.; Gao, Jay L.; Mills, David

2010-01-01

Time distribution and synchronization in deep space network are challenging due to long propagation delays, spacecraft movements, and relativistic effects. Further, the Network Time Protocol (NTP) designed for terrestrial networks may not work properly in space. In this work, we consider the time distribution protocol based on time message exchanges similar to Network Time Protocol (NTP). We present the Proximity-1 Space Link Interleaved Time Synchronization (PITS) algorithm that can work with the CCSDS Proximity-1 Space Data Link Protocol. The PITS algorithm provides faster time synchronization via two-way time transfer over proximity links, improves scalability as the number of spacecraft increase, lowers storage space requirement for collecting time samples, and is robust against packet loss and duplication which underlying protocol mechanisms provide.

Instant Messaging for Creating Interactive and Collaborative m-Learning Environments

Directory of Open Access Journals (Sweden)

James Kadirire

2007-06-01

Full Text Available 'Instant Messaging' (IM and 'Presence,' which is essentially the ability of being able to detect if other users are logged in on the network and send them messages in real time, has become one of the most popular applications of the Internet, causing people to want to stay connected to the Internet for inordinate amounts of time, a phenomena that also fosters a sense of "online community," that perhaps no other application has done previously (Alvestrand, 2002. This research looks at the use of mobile devices to send instant messages that can carry much more information than the short message service (SMS messages, but would be free to use, notwithstanding the price of getting online. We present a prototype IM system that can be used as a viable means of communicating and learning in higher education establishments. There is some evidence to show that learning using mobile devices reduces the formality of the learning experience, and helps engage reluctant learners and raise their self-confidence. In order for the learning process to be successful in online distance learning, unlike in the traditional face-to-face learning, attention must be paid to developing the participants' sense of community within their particular group. Instant messaging – or IM – is a natural medium for online community building and asynchronous/ synchronous peer discussions.

An Approach to Ad-hoc Messaging Networks Using Time Shifted Propagation

Directory of Open Access Journals (Sweden)

Christoph Fuchß

2007-10-01

Full Text Available Many communication devices, like mobile phones and PDAs, are enabled for near field communication by using Bluetooth. Many approaches dealt so far with the attempt to transfer mobile ad-hoc networks (MANET to the mechanism of the “fixed internet” to mobile networks. In order to achieve liability and robustness of common TCP connections routing algorithm in near field communication based networks become more sophisticated and complex. These mechanisms often do not reflect on the application’s particularities.Our approach of an ad-hoc messaging network (AMNET uses simple store-and-forward message passing to spread data asynchronously. We do not aim at the reliability of common internet networks but focus on application specific needs that can be covered by simple message passing mechanism. In this paper we will portray a powerful network by using simple devices and communication protocols on the basis of AMNETs. Simulation results of our AMNET approach provide insights towards speeding up the network setup process and to enable the use of AMNETs even with few participants by introducing a hybrid structure of infrastructure and mobile nodes.

Synchronizing spatiotemporal chaos by introducing a finite flat region in the local map

Directory of Open Access Journals (Sweden)

J. Y. Chen

2001-01-01

Full Text Available An approach to synchronize spatiotemporal chaos is proposed. It is achieved by introducing a finite flat region in the local map. By using this scheme, a number of orbits in both the drive and the response subsystems are forced to pass through a fixed point in every dimension. With only an arbitrary phase space variable as drive signal, synchronization of spatiotemporal chaos can be achieved rapidly in the response subsystem. This is an advantage when compared with other synchronization methods that require a linear combination of the original phase space variables.

Adaptative synchronization in multi-output fractional-order complex dynamical networks and secure communications

Science.gov (United States)

Mata-Machuca, Juan L.; Aguilar-López, Ricardo

2018-01-01

This work deals with the adaptative synchronization of complex dynamical networks with fractional-order nodes and its application in secure communications employing chaotic parameter modulation. The complex network is composed of multiple fractional-order systems with mismatch parameters and the coupling functions are given to realize the network synchronization. We introduce a fractional algebraic synchronizability condition (FASC) and a fractional algebraic identifiability condition (FAIC) which are used to know if the synchronization and parameters estimation problems can be solved. To overcome these problems, an adaptative synchronization methodology is designed; the strategy consists in proposing multiple receiver systems which tend to follow asymptotically the uncertain transmitters systems. The coupling functions and parameters of the receiver systems are adjusted continually according to a convenient sigmoid-like adaptative controller (SLAC), until the measurable output errors converge to zero, hence, synchronization between transmitter and receivers is achieved and message signals are recovered. Indeed, the stability analysis of the synchronization error is based on the fractional Lyapunov direct method. Finally, numerical results corroborate the satisfactory performance of the proposed scheme by means of the synchronization of a complex network consisting of several fractional-order unified chaotic systems.

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

Directory of Open Access Journals (Sweden)

Masayuki Murata

2011-08-01

Full Text Available 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.

An introduction to compositional methods for concurrency and their application to real-time

NARCIS (Netherlands)

Hooman, J.J.M.; Roever, de W.P.

1992-01-01

Formal methods to specify and verify concurrent programs with synchronous message passing are discussed. We stress the development towards compositional methods, i.e. methods in which the specification of a compound program can be inferred from specifications of its constituents without reference to

An energy efficient and dynamic time synchronization protocol for wireless sensor networks

Science.gov (United States)

Zhang, Anran; Bai, Fengshan

2017-01-01

Time synchronization is an important support technology of WSN(Wireless Sensor Network), and plays an irreplaceable role in the development of WSN. In view of the disadvantage of the traditional timing sync protocol for sensor networks (TPSN), we present a Physical Timing-sync Protocol (PTPSN) that aims at reducing the energy consumption of the synchronization process and realizes a dynamic Network. The algorithm broadcasts reference message to select some nodes in specific area. The receiver calculate offset of every selected node, and then calculate the average of offset to compensate for clock skew . At the same time ,we add time-filter process to ensure the security of the algorithm for time synchronization. The experiment results show that our algorithm is efficient in both saving energy consumption and dynamic network, and it can effectively resist attacks.

Performance of different synchronization measures in real data: A case study on electroencephalographic signals

Science.gov (United States)

Quian Quiroga, R.; Kraskov, A.; Kreuz, T.; Grassberger, P.

2002-04-01

We study the synchronization between left and right hemisphere rat electroencephalographic (EEG) channels by using various synchronization measures, namely nonlinear interdependences, phase synchronizations, mutual information, cross correlation, and the coherence function. In passing we show a close relation between two recently proposed phase synchronization measures and we extend the definition of one of them. In three typical examples we observe that except mutual information, all these measures give a useful quantification that is hard to be guessed beforehand from the raw data. Despite their differences, results are qualitatively the same. Therefore, we claim that the applied measures are valuable for the study of synchronization in real data. Moreover, in the particular case of EEG signals their use as complementary variables could be of clinical relevance.

Increasing the Operational Value of Event Messages

Science.gov (United States)

Li, Zhenping; Savkli, Cetin; Smith, Dan

2003-01-01

Assessing the health of a space mission has traditionally been performed using telemetry analysis tools. Parameter values are compared to known operational limits and are plotted over various time periods. This presentation begins with the notion that there is an incredible amount of untapped information contained within the mission s event message logs. Through creative advancements in message handling tools, the event message logs can be used to better assess spacecraft and ground system status and to highlight and report on conditions not readily apparent when messages are evaluated one-at-a-time during a real-time pass. Work in this area is being funded as part of a larger NASA effort at the Goddard Space Flight Center to create component-based, middleware-based, standards-based general purpose ground system architecture referred to as GMSEC - the GSFC Mission Services Evolution Center. The new capabilities and operational concepts for event display, event data analyses and data mining are being developed by Lockheed Martin and the new subsystem has been named GREAT - the GMSEC Reusable Event Analysis Toolkit. Planned for use on existing and future missions, GREAT has the potential to increase operational efficiency in areas of problem detection and analysis, general status reporting, and real-time situational awareness.

Synchronicity from Synchronized Chaos

Directory of Open Access Journals (Sweden)

Gregory S. Duane

2015-03-01

Full Text Available The synchronization of loosely-coupled chaotic oscillators, a phenomenon investigated intensively for the last two decades, may realize the philosophical concept of “synchronicity”—the commonplace notion that related eventsmysteriously occur at the same time. When extended to continuous media and/or large discrete arrays, and when general (non-identical correspondences are considered between states, intermittent synchronous relationships indeed become ubiquitous. Meaningful synchronicity follows naturally if meaningful events are identified with coherent structures, defined by internal synchronization between remote degrees of freedom; a condition that has been posited as necessary for synchronizability with an external system. The important case of synchronization between mind and matter is realized if mind is analogized to a computer model, synchronizing with a sporadically observed system, as in meteorological data assimilation. Evidence for the ubiquity of synchronization is reviewed along with recent proposals that: (1 synchronization of different models of the same objective process may be an expeditious route to improved computational modeling and may also describe the functioning of conscious brains; and (2 the nonlocality in quantum phenomena implied by Bell’s theorem may be explained in a variety of deterministic (hidden variable interpretations if the quantum world resides on a generalized synchronization “manifold”.

Middleware Proxy: A Request-Driven Messaging Broker For High Volume Data Distribution

CERN Document Server

Sliwinski, W; Dworak, A

2014-01-01

Nowadays, all major infrastructures and data centres (commercial and scientific) make an extensive use of the publish-subscribe messaging paradigm, which helps to decouple the message sender (publisher) from the message receiver (consumer). This paradigm is also heavily used in the CERN Accelerator Control system, in Proxy broker - critical part of the Controls Middleware (CMW) project. Proxy provides the aforementioned publish-subscribe facility and also supports execution of synchronous read and write operations. Moreover, it enables service scalability and dramatically reduces the network resources and overhead (CPU and memory) on publisher machine, required to serve all subscriptions. Proxy was developed in modern C++, using state of the art programming techniques (e.g. Boost) and following recommended software patterns for achieving low-latency and high concurrency. The outstanding performance of the Proxy infrastructure was confirmed during the last 3 years by delivering the high volume of LHC equipment...

Security analysis of communication system based on the synchronization of different order chaotic systems

International Nuclear Information System (INIS)

Alvarez, Gonzalo; Hernandez, Luis; Munoz, Jaime; Montoya, Fausto; Li Shujun

2005-01-01

This Letter analyzes the security weakness of a recently proposed communication method based on chaotic modulation and masking using synchronization of two chaotic systems with different orders. It is shown that its application to secure communication is unsafe, because it can be broken in two different ways, by high-pass filtering and by reduced order system synchronization, without knowing neither the system parameter values nor the system key

Chaos Synchronization Based on Unknown Input Proportional Multiple-Integral Fuzzy Observer

Directory of Open Access Journals (Sweden)

T. Youssef

2013-01-01

Full Text Available This paper presents an unknown input Proportional Multiple-Integral Observer (PIO for synchronization of chaotic systems based on Takagi-Sugeno (TS fuzzy chaotic models subject to unmeasurable decision variables and unknown input. In a secure communication configuration, this unknown input is regarded as a message encoded in the chaotic system and recovered by the proposed PIO. Both states and outputs of the fuzzy chaotic models are subject to polynomial unknown input with kth derivative zero. Using Lyapunov stability theory, sufficient design conditions for synchronization are proposed. The PIO gains matrices are obtained by resolving linear matrix inequalities (LMIs constraints. Simulation results show through two TS fuzzy chaotic models the validity of the proposed method.

On projective synchronization of hyperchaotic complex nonlinear systems based on passive theory for secure communications

International Nuclear Information System (INIS)

Mahmoud, Gamal M; Mahmoud, Emad E; Arafa, Ayman A

2013-01-01

In this paper we deal with the projective synchronization (PS) of hyperchaotic complex nonlinear systems and its application in secure communications based on passive theory. The unpredictability of the scaling factor in PS can additionally enhance the security of communications. In this paper, a scheme for secure message transmission is proposed, and we try to transmit more than one large or bounded message from the transmitter to the receiver. The new hyperchaotic complex Lorenz system is employed to encrypt these messages. In the transmitter, the original messages are modulated into its parameter. In the receiver, we assume that the parameter of the receiver system is uncertain. The controllers and corresponding parameter update law are constructed to achieve PS between the transmitter and receiver system with an uncertain parameter, and identify the unknown parameter via passive theory. The original messages can be recovered successfully through some simple operations by the estimated parameter. Numerical results have verified the effectiveness and feasibility of the presented method. (paper)

Synchronous Parallel System for Emulation and Discrete Event Simulation

Science.gov (United States)

Steinman, Jeffrey S. (Inventor)

2001-01-01

A synchronous parallel system for emulation and discrete event simulation having parallel nodes responds to received messages at each node by generating event objects having individual time stamps, stores only the changes to the state variables of the simulation object attributable to the event object and produces corresponding messages. The system refrains from transmitting the messages and changing the state variables while it determines whether the changes are superseded, and then stores the unchanged state variables in the event object for later restoral to the simulation object if called for. This determination preferably includes sensing the time stamp of each new event object and determining which new event object has the earliest time stamp as the local event horizon, determining the earliest local event horizon of the nodes as the global event horizon, and ignoring events whose time stamps are less than the global event horizon. Host processing between the system and external terminals enables such a terminal to query, monitor, command or participate with a simulation object during the simulation process.

Enhancing Time Synchronization Support in Wireless Sensor Networks.

Science.gov (United States)

Tavares Bruscato, Leandro; Heimfarth, Tales; Pignaton de Freitas, Edison

2017-12-20

With the emerging Internet of Things (IoT) technology becoming reality, a number of applications are being proposed. Several of these applications are highly dependent on wireless sensor networks (WSN) to acquire data from the surrounding environment. In order to be really useful for most of applications, the acquired data must be coherent in terms of the time in which they are acquired, which implies that the entire sensor network presents a certain level of time synchronization. Moreover, to efficiently exchange and forward data, many communication protocols used in WSN rely also on time synchronization among the sensor nodes. Observing the importance in complying with this need for time synchronization, this work focuses on the second synchronization problem, proposing, implementing and testing a time synchronization service for low-power WSN using low frequency real-time clocks in each node. To implement this service, three algorithms based on different strategies are proposed: one based on an auto-correction approach, the second based on a prediction mechanism, while the third uses an analytical correction mechanism. Their goal is the same, i.e., to make the clocks of the sensor nodes converge as quickly as possible and then to keep them most similar as possible. This goal comes along with the requirement to keep low energy consumption. Differently from other works in the literature, the proposal here is independent of any specific protocol, i.e., it may be adapted to be used in different protocols. Moreover, it explores the minimum number of synchronization messages by means of a smart clock update strategy, allowing the trade-off between the desired level of synchronization and the associated energy consumption. Experimental results, which includes data acquired from simulations and testbed deployments, provide evidence of the success in meeting this goal, as well as providing means to compare these three approaches considering the best synchronization

Enhancing Time Synchronization Support in Wireless Sensor Networks

Science.gov (United States)

Tavares Bruscato, Leandro; Heimfarth, Tales; Pignaton de Freitas, Edison

2017-01-01

With the emerging Internet of Things (IoT) technology becoming reality, a number of applications are being proposed. Several of these applications are highly dependent on wireless sensor networks (WSN) to acquire data from the surrounding environment. In order to be really useful for most of applications, the acquired data must be coherent in terms of the time in which they are acquired, which implies that the entire sensor network presents a certain level of time synchronization. Moreover, to efficiently exchange and forward data, many communication protocols used in WSN rely also on time synchronization among the sensor nodes. Observing the importance in complying with this need for time synchronization, this work focuses on the second synchronization problem, proposing, implementing and testing a time synchronization service for low-power WSN using low frequency real-time clocks in each node. To implement this service, three algorithms based on different strategies are proposed: one based on an auto-correction approach, the second based on a prediction mechanism, while the third uses an analytical correction mechanism. Their goal is the same, i.e., to make the clocks of the sensor nodes converge as quickly as possible and then to keep them most similar as possible. This goal comes along with the requirement to keep low energy consumption. Differently from other works in the literature, the proposal here is independent of any specific protocol, i.e., it may be adapted to be used in different protocols. Moreover, it explores the minimum number of synchronization messages by means of a smart clock update strategy, allowing the trade-off between the desired level of synchronization and the associated energy consumption. Experimental results, which includes data acquired from simulations and testbed deployments, provide evidence of the success in meeting this goal, as well as providing means to compare these three approaches considering the best synchronization

The Hamlet design entry system: on the implementation of synchronous channels

NARCIS (Netherlands)

M.R. van Steen

1994-01-01

textabstractThe graphical Hamlet Application Design Language (ADL) has been developed to support the construction of parallel applications. The language is based on a notion of processes communicating by means of message-passing. One of the goals of ADL is that its implementation should allow

The Role of Synchronous Virtual Reference in Teaching and Learning: A Grounded Theory Analysis of Instant Messaging Transcripts

Science.gov (United States)

Passonneau, Sarah; Coffey, Dan

2011-01-01

Electronic communication technologies continue to change the landscape of reference services. For many users, virtual communication is the preferred means of conversing. Synchronous virtual reference, similar to other synchronous means of communication, is an important method for reaching students and for providing teaching and learning…

Scalable High Performance Message Passing over InfiniBand for Open MPI

Energy Technology Data Exchange (ETDEWEB)

Friedley, A; Hoefler, T; Leininger, M L; Lumsdaine, A

2007-10-24

InfiniBand (IB) is a popular network technology for modern high-performance computing systems. MPI implementations traditionally support IB using a reliable, connection-oriented (RC) transport. However, per-process resource usage that grows linearly with the number of processes, makes this approach prohibitive for large-scale systems. IB provides an alternative in the form of a connectionless unreliable datagram transport (UD), which allows for near-constant resource usage and initialization overhead as the process count increases. This paper describes a UD-based implementation for IB in Open MPI as a scalable alternative to existing RC-based schemes. We use the software reliability capabilities of Open MPI to provide the guaranteed delivery semantics required by MPI. Results show that UD not only requires fewer resources at scale, but also allows for shorter MPI startup times. A connectionless model also improves performance for applications that tend to send small messages to many different processes.

Technical Evaluation Report 14: Chat and Instant Messaging Systems (synchronous: Report 2/ 3

Directory of Open Access Journals (Sweden)

Ellen Kinsel

2002-10-01

Full Text Available This study extends the earlier review of online chat systems (Report 6, by reviewing a further seven products that provide text-based instant messaging (IM. The functionality of these products in distance education contexts is stressed in relation to their comparative costs, complexity, control, clarity, technical framework, and other functional options.

An Examination of Adolescent Recall of Anti-Smoking Messages: Attitudes, Message Type, and Message Perceptions.

Science.gov (United States)

Bigsby, Elisabeth; Monahan, Jennifer L; Ewoldsen, David R

2017-04-01

Delayed message recall may be influenced by currently held accessible attitudes, the nature of the message, and message perceptions (perception of bias and message elaboration). This study examined the potential of message perceptions to mediate the influence of valenced attitude accessibility and message type on unaided recall of anti-smoking Public Service Announcements (PSAs). In a field experiment, ninth grade students (N = 244) watched three PSAs and responded to items on laptop computers. Twelve weeks later, follow-up telephone surveys were conducted to assess unaided recall. Both valenced attitude accessibility and message type were associated with message perceptions. However, only perception of message bias partially mediated the relationship between message type and unaided recall.

Control and switching synchronization of fractional order chaotic systems using active control technique

KAUST Repository

Radwan, A.G.; Moaddy, K.; Salama, Khaled N.; Momani, S.; Hashim, I.

2013-01-01

This paper discusses the continuous effect of the fractional order parameter of the Lü system where the system response starts stable, passing by chaotic behavior then reaching periodic response as the fractional-order increases. In addition, this paper presents the concept of synchronization of different fractional order chaotic systems using active control technique. Four different synchronization cases are introduced based on the switching parameters. Also, the static and dynamic synchronizations can be obtained when the switching parameters are functions of time. The nonstandard finite difference method is used for the numerical solution of the fractional order master and slave systems. Many numeric simulations are presented to validate the concept for different fractional order parameters.

Control and switching synchronization of fractional order chaotic systems using active control technique

KAUST Repository

Radwan, A.G.

2013-03-13

This paper discusses the continuous effect of the fractional order parameter of the Lü system where the system response starts stable, passing by chaotic behavior then reaching periodic response as the fractional-order increases. In addition, this paper presents the concept of synchronization of different fractional order chaotic systems using active control technique. Four different synchronization cases are introduced based on the switching parameters. Also, the static and dynamic synchronizations can be obtained when the switching parameters are functions of time. The nonstandard finite difference method is used for the numerical solution of the fractional order master and slave systems. Many numeric simulations are presented to validate the concept for different fractional order parameters.

Facility-wide synchronization of standard FAIR equipment controllers

International Nuclear Information System (INIS)

Rauch, S.; Terpstra, W.; Panschow, W.; Thieme, M.; Prados, C.; Zweig, M.; Kreider, M.; Beck, D.; Bär, R.

2012-01-01

The standard equipment controller under development for the new FAIR accelerator facility is the Scalable Control Unit (SCU). It is designed to synchronize and control the actions of up to 12 purpose-built slave cards, connected in a proprietary crate by a parallel backplane. Inter-crate coordination and facility-wide synchronization are a core FAIR requirement and thus precise timing of SCU slave actions is of vital importance. The SCU consists primarily of two components, an x86 COM Express daughter board and a carrier board with an Altera Arria II GX FPGA, interconnected by PCI Express. The x86 receives configuration and set values with which it programs the real-time event-condition-action (ECA) unit in the FPGA. The ECA unit receives event messages via the timing network, which also synchronizes the clocks of all SCUs in the facility using White Rabbit. Matching events trigger actions on the SCU slave cards such as: ramping magnets, triggering kickers, etc. Timing requirements differ depending on the action taken. For softer real-time actions, an interrupt can be generated for complex processing on the x86. Alternatively, the FPGA can directly fire a pulse out a LEMO output or an immediate SCU bus operation. The delay and synchronization achievable in each case differs and this paper examines the timing performance of each to determine which approach is appropriate for the required actions. (author)

Simple cellular automaton model for traffic breakdown, highway capacity, and synchronized flow

Science.gov (United States)

Kerner, Boris S.; Klenov, Sergey L.; Schreckenberg, Michael

2011-10-01

We present a simple cellular automaton (CA) model for two-lane roads explaining the physics of traffic breakdown, highway capacity, and synchronized flow. The model consists of the rules “acceleration,” “deceleration,” “randomization,” and “motion” of the Nagel-Schreckenberg CA model as well as “overacceleration through lane changing to the faster lane,” “comparison of vehicle gap with the synchronization gap,” and “speed adaptation within the synchronization gap” of Kerner's three-phase traffic theory. We show that these few rules of the CA model can appropriately simulate fundamental empirical features of traffic breakdown and highway capacity found in traffic data measured over years in different countries, like characteristics of synchronized flow, the existence of the spontaneous and induced breakdowns at the same bottleneck, and associated probabilistic features of traffic breakdown and highway capacity. Single-vehicle data derived in model simulations show that synchronized flow first occurs and then self-maintains due to a spatiotemporal competition between speed adaptation to a slower speed of the preceding vehicle and passing of this slower vehicle. We find that the application of simple dependences of randomization probability and synchronization gap on driving situation allows us to explain the physics of moving synchronized flow patterns and the pinch effect in synchronized flow as observed in real traffic data.

A Bidirectional Generalized Synchronization Theorem-Based Chaotic Pseudo-random Number Generator

Directory of Open Access Journals (Sweden)

Han Shuangshuang

2013-07-01

Full Text Available Based on a bidirectional generalized synchronization theorem for discrete chaos system, this paper introduces a new 5-dimensional bidirectional generalized chaos synchronization system (BGCSDS, whose prototype is a novel chaotic system introduced in [12]. Numerical simulation showed that two pair variables of the BGCSDS achieve generalized chaos synchronization via a transform H.A chaos-based pseudo-random number generator (CPNG was designed by the new BGCSDS. Using the FIPS-140-2 tests issued by the National Institute of Standard and Technology (NIST verified the randomness of the 1000 binary number sequences generated via the CPNG and the RC4 algorithm respectively. The results showed that all the tested sequences passed the FIPS-140-2 tests. The confidence interval analysis showed the statistical properties of the randomness of the sequences generated via the CPNG and the RC4 algorithm do not have significant differences.

Virtually-synchronous communication based on a weak failure suspector

Science.gov (United States)

Schiper, Andre; Ricciardi, Aleta

1993-01-01

Failure detectors (or, more accurately Failure Suspectors (FS)) appear to be a fundamental service upon which to build fault-tolerant, distributed applications. This paper shows that a FS with very weak semantics (i.e., that delivers failure and recovery information in no specific order) suffices to implement virtually-synchronous communication (VSC) in an asynchronous system subject to process crash failures and network partitions. The VSC paradigm is particularly useful in asynchronous systems and greatly simplifies building fault-tolerant applications that mask failures by replicating processes. We suggest a three-component architecture to implement virtually-synchronous communication: (1) at the lowest level, the FS component; (2) on top of it, a component (2a) that defines new views; and (3) a component (2b) that reliably multicasts messages within a view. The issues covered in this paper also lead to a better understanding of the various membership service semantics proposed in recent literature.

A Novel Single Pass Authenticated Encryption Stream Cipher for Software Defined Radios

DEFF Research Database (Denmark)

Khajuria, Samant

2012-01-01

to propose cryptographic services such as confidentiality, integrity and authentication. Therefore, integration of security services into SDR devices is essential. Authenticated Encryption schemes donate the class of cryptographic algorithms that are designed for protecting both message confidentiality....... This makes authenticated encryption very attractive for low-cost low-power hardware implementations, as it allows for the substantial decrease in the circuit area and power consumed compared to the traditional schemes. In this thesis, an authenticated encryption scheme is proposed with the focus of achieving...... high throughput and low overhead for SDRs. The thesis is divided into two research topics. One topic is the design of a 1-pass authenticated encryption scheme that can accomplish both message secrecy and authenticity in a single cryptographic primitive. The other topic is the implementation...

Chaos and its synchronization in two-neuron systems with discrete delays

International Nuclear Information System (INIS)

Zhou Shangbo; Liao Xiaofeng; Yu Juebang; Wong Kwokwo

2004-01-01

It is well known that complex dynamic behaviors exist in time-delayed neural systems. Infinite positive Lyapunov exponents can be found in time-delayed chaotic systems since the dimension of such systems is infinite. However, theoretical and experimental models studied thus far are low dimensional systems with only one positive Lyapunov exponent. Consequently, messages masked by such chaotic systems are shown to be easily extracted in some cases. Therefore, communication system with a higher security level can be design by means of the time-delayed neuron systems. In this paper, we firstly investigate the dynamical behaviors of two-neuron systems with discrete delays. Then, the chaos synchronization in time-delayed neuron system is studied based on the method of designing the coupled system and employing Krasovskii-Lyapunov theory to search the synchronization conditions. Numerical results illustrate the correctness of our theoretical analyses

Synchronization and anti-synchronization coexist in Chen-Lee chaotic systems

International Nuclear Information System (INIS)

Chen, J.-H.; Chen, H.-K.; Lin, Y.-K.

2009-01-01

This study demonstrates that synchronization and anti-synchronization can coexist in Chen-Lee chaotic systems by direct linear coupling. Based on Lyapunov's direct method, a linear controller was designed to assure that two different types of synchronization can simultaneously be achieved. Further, the hybrid projective synchronization of Chen-Lee chaotic systems was studied using a nonlinear control scheme. The nonlinear controller was designed according to the Lyapunov stability theory to guarantee the hybrid projective synchronization, including synchronization, anti-synchronization, and projective synchronization. Finally, numerical examples are presented in order to illustrate the proposed synchronization approach.

The Physical Therapy and Society Summit (PASS) Meeting: observations and opportunities.

Science.gov (United States)

Kigin, Colleen M; Rodgers, Mary M; Wolf, Steven L

2010-11-01

The construct of delivering high-quality and cost-effective health care is in flux, and the profession must strategically plan how to meet the needs of society. In 2006, the House of Delegates of the American Physical Therapy Association passed a motion to convene a summit on "how physical therapists can meet current, evolving, and future societal health care needs." The Physical Therapy and Society Summit (PASS) meeting on February 27-28, 2009, in Leesburg, Virginia, sent a clear message that for physical therapists to be effective and thrive in the health care environment of the future, a paradigm shift is required. During the PASS meeting, participants reframed our traditional focus on the physical therapist and the patient/client (consumer) to one in which physical therapists are an integral part of a collaborative, multidisciplinary health care team with the health care consumer as its focus. The PASS Steering Committee recognized that some of the opportunities that surfaced during the PASS meeting may be disruptive or may not be within the profession's present strategic or tactical plans. Thus, adopting a framework that helps to establish the need for change that is provocative and potentially disruptive to our present care delivery, yet prioritizes opportunities, is a critical and essential step. Each of us in the physical therapy profession must take on post-PASS roles and responsibilities to accomplish the systemic change that is so intimately intertwined with our destiny. This article offers a perspective of the dynamic dialogue and suggestions that emerged from the PASS event, providing further opportunities for discussion and action within our profession.

A New Torque Control System of Permanent Magnet Synchronous Motor

Directory of Open Access Journals (Sweden)

Evstratov Andrey

2017-01-01

Full Text Available The article describes a new approach to control of permanent magnet synchronous motor drive based on the analysis of the electromechanical transformation. The proposed control system provides quick response and low ripple of the motor torque and flux. To synthesis this control system, the authors put the electromagnetic torque and the modulus of stator flux vector as controlled values and use the Lyapunov’s second method. In addition, the stator voltage constriction and ability of low-pass filtration are taken into account. The investigation of the proposed control system has carried out with the simulation and the experimental research which have confirmed that the proposed control system correspond to all above-mentioned control tasks and the permanent magnet synchronous motor controlled under this system may be recommended to use in robotics.

Class hierarchical test case generation algorithm based on expanded EMDPN model

Institute of Scientific and Technical Information of China (English)

LI Jun-yi; GONG Hong-fang; HU Ji-ping; ZOU Bei-ji; SUN Jia-guang

2006-01-01

A new model of event and message driven Petri network(EMDPN) based on the characteristic of class interaction for messages passing between two objects was extended. Using EMDPN interaction graph, a class hierarchical test-case generation algorithm with cooperated paths (copaths) was proposed, which can be used to solve the problems resulting from the class inheritance mechanism encountered in object-oriented software testing such as oracle, message transfer errors, and unreachable statement. Finally, the testing sufficiency was analyzed with the ordered sequence testing criterion(OSC). The results indicate that the test cases stemmed from newly proposed automatic algorithm of copaths generation satisfies synchronization message sequences testing criteria, therefore the proposed new algorithm of copaths generation has a good coverage rate.

Fast sparsely synchronized brain rhythms in a scale-free neural network.

Science.gov (United States)

Kim, Sang-Yoon; Lim, Woochang

2015-08-01

We consider a directed version of the Barabási-Albert scale-free network model with symmetric preferential attachment with the same in- and out-degrees and study the emergence of sparsely synchronized rhythms for a fixed attachment degree in an inhibitory population of fast-spiking Izhikevich interneurons. Fast sparsely synchronized rhythms with stochastic and intermittent neuronal discharges are found to appear for large values of J (synaptic inhibition strength) and D (noise intensity). For an intensive study we fix J at a sufficiently large value and investigate the population states by increasing D. For small D, full synchronization with the same population-rhythm frequency fp and mean firing rate (MFR) fi of individual neurons occurs, while for large D partial synchronization with fp>〈fi〉 (〈fi〉: ensemble-averaged MFR) appears due to intermittent discharge of individual neurons; in particular, the case of fp>4〈fi〉 is referred to as sparse synchronization. For the case of partial and sparse synchronization, MFRs of individual neurons vary depending on their degrees. As D passes a critical value D* (which is determined by employing an order parameter), a transition to unsynchronization occurs due to the destructive role of noise to spoil the pacing between sparse spikes. For Dsynchronization emerges in the whole population because the spatial correlation length between the neuronal pairs covers the whole system. Furthermore, the degree of population synchronization is also measured in terms of two types of realistic statistical-mechanical measures. Only for the partial and sparse synchronization do contributions of individual neuronal dynamics to population synchronization change depending on their degrees, unlike in the case of full synchronization. Consequently, dynamics of individual neurons reveal the inhomogeneous network structure for the case of partial and sparse synchronization, which is in contrast to the case of

Fast sparsely synchronized brain rhythms in a scale-free neural network

Science.gov (United States)

Kim, Sang-Yoon; Lim, Woochang

2015-08-01

We consider a directed version of the Barabási-Albert scale-free network model with symmetric preferential attachment with the same in- and out-degrees and study the emergence of sparsely synchronized rhythms for a fixed attachment degree in an inhibitory population of fast-spiking Izhikevich interneurons. Fast sparsely synchronized rhythms with stochastic and intermittent neuronal discharges are found to appear for large values of J (synaptic inhibition strength) and D (noise intensity). For an intensive study we fix J at a sufficiently large value and investigate the population states by increasing D . For small D , full synchronization with the same population-rhythm frequency fp and mean firing rate (MFR) fi of individual neurons occurs, while for large D partial synchronization with fp> ( : ensemble-averaged MFR) appears due to intermittent discharge of individual neurons; in particular, the case of fp>4 is referred to as sparse synchronization. For the case of partial and sparse synchronization, MFRs of individual neurons vary depending on their degrees. As D passes a critical value D* (which is determined by employing an order parameter), a transition to unsynchronization occurs due to the destructive role of noise to spoil the pacing between sparse spikes. For D synchronization emerges in the whole population because the spatial correlation length between the neuronal pairs covers the whole system. Furthermore, the degree of population synchronization is also measured in terms of two types of realistic statistical-mechanical measures. Only for the partial and sparse synchronization do contributions of individual neuronal dynamics to population synchronization change depending on their degrees, unlike in the case of full synchronization. Consequently, dynamics of individual neurons reveal the inhomogeneous network structure for the case of partial and sparse synchronization, which is in contrast to the case of statistically homogeneous

Designing Anti-Binge Drinking Prevention Messages: Message Framing vs. Evidence Type.

Science.gov (United States)

Kang, Hannah; Lee, Moon J

2017-09-27

We investigated whether presenting anti-binge drinking health campaign messages in different message framing and evidence types influences college students' intention to avoid binge drinking, based on prospect theory (PT) and exemplification theory. A 2 (message framing: loss-framed message/gain-framed message) X 2 (evidence type: statistical/narrative) between-subjects factorial design with a control group was conducted with 156 college students. College students who were exposed to the loss-framed message condition exhibited a higher level of intention to avoid binge drinking in the near future than those who did not see any messages (the control group). This finding was mainly among non-binge drinkers. Regardless of evidence type, those who were exposed to the messages exhibited a higher level of intention to avoid binge drinking than those in the control group. This is also mainly among non-binge drinkers. We also found the main effects of message framing and evidence type on attitude toward the message and the main effect of message framing on attitude toward drinking.

Advanced Messaging Concept Development Basic Safety Message

Data.gov (United States)

Department of Transportation — Contains all Basic Safety Messages (BSMs) collected during the Advanced Messaging Concept Development (AMCD) field testing program. For this project, all of the Part...

When message-frame fits salient cultural-frame, messages feel more persuasive.

Science.gov (United States)

Uskul, Ayse K; Oyserman, Daphna

2010-03-01

The present study examines the persuasive effects of tailored health messages comparing those tailored to match (versus not match) both chronic cultural frame and momentarily salient cultural frame. Evidence from two studies (Study 1: n = 72 European Americans; Study 2: n = 48 Asian Americans) supports the hypothesis that message persuasiveness increases when chronic cultural frame, health message tailoring and momentarily salient cultural frame all match. The hypothesis was tested using a message about health risks of caffeine consumption among individuals prescreened to be regular caffeine consumers. After being primed for individualism, European Americans who read a health message that focused on the personal self were more likely to accept the message-they found it more persuasive, believed they were more at risk and engaged in more message-congruent behaviour. These effects were also found among Asian Americans who were primed for collectivism and who read a health message that focused on relational obligations. The findings point to the importance of investigating the role of situational cues in persuasive effects of health messages and suggest that matching content to primed frame consistent with the chronic frame may be a way to know what to match messages to.

Saguaro: A Distributed Operating System Based on Pools of Servers.

Science.gov (United States)

1988-03-25

asynchronous message passing, multicast, and semaphores are supported. We have found this flexibility to be very useful for distributed programming. The...variety of communication primitives provided by SR has facilitated the research of Stella Atkins, who was a visiting professor at Arizona during Spring...data bits in a raw communication channel to help keep the source and destination synchronized , Psync explicitly embeds timing information drawn from the

Synchronization of metronomes

Science.gov (United States)

Pantaleone, James

2002-10-01

Synchronization is a common phenomenon in physical and biological systems. We examine the synchronization of two (and more) metronomes placed on a freely moving base. The small motion of the base couples the pendulums causing synchronization. The synchronization is generally in-phase, with antiphase synchronization occurring only under special conditions. The metronome system provides a mechanical realization of the popular Kuramoto model for synchronization of biological oscillators, and is excellent for classroom demonstrations and an undergraduate physics lab.

A Self-Stabilizing Synchronization Protocol for Arbitrary Digraphs

Science.gov (United States)

Malekpour, Mahyar R.

2011-01-01

This paper presents a self-stabilizing distributed clock synchronization protocol in the absence of faults in the system. It is focused on the distributed clock synchronization of an arbitrary, non-partitioned digraph ranging from fully connected to 1-connected networks of nodes while allowing for differences in the network elements. This protocol does not rely on assumptions about the initial state of the system, other than the presence of at least one node, and no central clock or a centrally generated signal, pulse, or message is used. Nodes are anonymous, i.e., they do not have unique identities. There is no theoretical limit on the maximum number of participating nodes. The only constraint on the behavior of the node is that the interactions with other nodes are restricted to defined links and interfaces. This protocol deterministically converges within a time bound that is a linear function of the self-stabilization period. We present an outline of a deductive proof of the correctness of the protocol. A bounded model of the protocol was mechanically verified for a variety of topologies. Results of the mechanical proof of the correctness of the protocol are provided. The model checking results have verified the correctness of the protocol as they apply to the networks with unidirectional and bidirectional links. In addition, the results confirm the claims of determinism and linear convergence. As a result, we conjecture that the protocol solves the general case of this problem. We also present several variations of the protocol and discuss that this synchronization protocol is indeed an emergent system.

A web-based and mobile patient-centered ''microblog'' messaging platform to improve care team communication in acute care.

Science.gov (United States)

Dalal, Anuj K; Schnipper, Jeffrey; Massaro, Anthony; Hanna, John; Mlaver, Eli; McNally, Kelly; Stade, Diana; Morrison, Constance; Bates, David W

2017-04-01

Communication in acute care settings is fragmented and occurs asynchronously via a variety of electronic modalities. Providers are often not on the same page with regard to the plan of care. We designed and developed a secure, patient-centered "microblog" messaging platform that identifies care team members by synchronizing with the electronic health record, and directs providers to a single forum where they can communicate about the plan of care. The system was used for 35% of patients admitted to a medical intensive care unit over a 6-month period. Major themes in messages included care coordination (49%), clinical summarization (29%), and care team collaboration (27%). Message transparency and persistence were seen as useful features by 83% and 62% of respondents, respectively. Availability of alternative messaging tools and variable use by non-unit providers were seen as main barriers to adoption by 83% and 62% of respondents, respectively. This approach has much potential to improve communication across settings once barriers are addressed. © The Author 2016. Published by Oxford University Press on behalf of the American Medical Informatics Association. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

Development of Client Environments for a Synchronization System based on Events; Desarrollo de Entornos Cliente para un Sistema de Sincronizacion Basado en Eventos

Energy Technology Data Exchange (ETDEWEB)

Pereira, A.; Vega, J.

2005-07-01

The Asynchronous Event Distribution System (AEDS) was built to provides synchronization resources within the TJ-II local area network. It is a software system developed to add soft synchronization capabilities to the TJ-II data acquisition, control and analysis environments Soft synchronization signifies that AEDS is not a realtime system. In fact, AEDS is based on TCP/IP over ETHERNET networks. However, its response time is adequate for practical purposes when synchronization requirements can support some delay between event dispatch and message reception. Event broadcasters (or synchronization servers in AEDS terminology) are Windows computers. Destination computers (or synchronization clients) were also Windows machines in the first version of AEDS. However, this fact imposed a very important limitation on synchronization capabilities. to overcome this situation, synchronization clients for different environments have been added to AEDS: time-sharing operating systems (UNIX and LINUX), real-time operating systems (OS9 and VxWorks) and Java applications. The synchronization primitives that operate in these systems are very different between them and therefore, several approaches were chosen in order to provide the same functionality to the various environments. POSLX thread library with its basic synchronization primitives (mutex and conditions variables) was used to accomplish this task on UNIX/LINUX systems, IPC mechanisms for concurrent processes on OS9 and VxWorks real time operating systems, and synchronized-wait/notify primitives on Java virtual machines. (Author) 11 refs.

A Visualized Message Interface (VMI) for intelligent messaging services

International Nuclear Information System (INIS)

Endo, T.; Kasahara, H.; Nakagawa, T.

1984-01-01

In CCITT, Message Handling Systems (MHS) have been studied from the viewpoint of communications protocol standardization. In addition to MHS services, Message Processing (MP) services, such as image processing, filing and retrieving services, will come into increasing demand in office automation field. These messaging services, including MHS services, can be thought of as Intelligent Messaging (IM) services. IM services include many basic services, optional user facilities and service parameters. Accordingly, it is necessary to deal with these parameters and MP procedures in as systematic and user-friendly a manner as possible. As one step towards realizing a user-friendly IM services interface, the characteristics of IM service parameters are studied and a Visualized Message Interface (VMI) which resembles a conventional letter exchange format is presented. The concept of VMI formation is discussed using the generic document structure concept as well as a Screen Interface and Protocol Interface conversion package

Does the Screening Status of Message Characters Affect Message Effects?

Science.gov (United States)

Alber, Julia M.; Glanz, Karen

2018-01-01

Public health messages can be used to increase awareness about colorectal cancer screenings. Free or inexpensive images for creating health messages are readily available, yet little is known about how a pictured individual's engagement in the behavior of interest affects message outcomes. Participants (N = 360), aged 50 to 75 years, completed an…

Open Science Grid (OSG) Ticket Synchronization: Keeping Your Home Field Advantage In A Distributed Environment

International Nuclear Information System (INIS)

Gross, Kyle; Hayashi, Soichi; Teige, Scott; Quick, Robert

2012-01-01

Large distributed computing collaborations, such as the Worldwide LHC Computing Grid (WLCG), face many issues when it comes to providing a working grid environment for their users. One of these is exchanging tickets between various ticketing systems in use by grid collaborations. Ticket systems such as Footprints, RT, Remedy, and ServiceNow all have different schema that must be addressed in order to provide a reliable exchange of information between support entities and users in different grid environments. To combat this problem, OSG Operations has created a ticket synchronization interface called GOC-TX that relies on web services instead of error-prone email parsing methods of the past. Synchronizing tickets between different ticketing systems allows any user or support entity to work on a ticket in their home environment, thus providing a familiar and comfortable place to provide updates without having to learn another ticketing system. The interface is built in a way that it is generic enough that it can be customized for nearly any ticketing system with a web-service interface with only minor changes. This allows us to be flexible and rapidly bring new ticket synchronization online. Synchronization can be triggered by different methods including mail, web services interface, and active messaging. GOC-TX currently interfaces with Global Grid User Support (GGUS) for WLCG, Remedy at Brookhaven National Lab (BNL), and Request Tracker (RT) at the Virtual Data Toolkit (VDT). Work is progressing on the Fermi National Accelerator Laboratory (FNAL) ServiceNow synchronization. This paper will explain the problems faced by OSG and how they led OSG to create and implement this ticket synchronization system along with the technical details that allow synchronization to be preformed at a production level.

Open Science Grid (OSG) Ticket Synchronization: Keeping Your Home Field Advantage In A Distributed Environment

Science.gov (United States)

Gross, Kyle; Hayashi, Soichi; Teige, Scott; Quick, Robert

2012-12-01

Large distributed computing collaborations, such as the Worldwide LHC Computing Grid (WLCG), face many issues when it comes to providing a working grid environment for their users. One of these is exchanging tickets between various ticketing systems in use by grid collaborations. Ticket systems such as Footprints, RT, Remedy, and ServiceNow all have different schema that must be addressed in order to provide a reliable exchange of information between support entities and users in different grid environments. To combat this problem, OSG Operations has created a ticket synchronization interface called GOC-TX that relies on web services instead of error-prone email parsing methods of the past. Synchronizing tickets between different ticketing systems allows any user or support entity to work on a ticket in their home environment, thus providing a familiar and comfortable place to provide updates without having to learn another ticketing system. The interface is built in a way that it is generic enough that it can be customized for nearly any ticketing system with a web-service interface with only minor changes. This allows us to be flexible and rapidly bring new ticket synchronization online. Synchronization can be triggered by different methods including mail, web services interface, and active messaging. GOC-TX currently interfaces with Global Grid User Support (GGUS) for WLCG, Remedy at Brookhaven National Lab (BNL), and Request Tracker (RT) at the Virtual Data Toolkit (VDT). Work is progressing on the Fermi National Accelerator Laboratory (FNAL) ServiceNow synchronization. This paper will explain the problems faced by OSG and how they led OSG to create and implement this ticket synchronization system along with the technical details that allow synchronization to be preformed at a production level.

DMS message design workshops.

Science.gov (United States)

2009-03-01

This report summarizes the training conducted statewide regarding the design and display of messages on : dynamic message signs. The training is based on the Dynamic Message Sign Message Design and Display : Manual (0-4023-P3). Researchers developed ...

Social Presence in the Web-based Synchronous Secondary Classroom

Directory of Open Access Journals (Sweden)

Eric Nippard

2007-02-01

Full Text Available he purpose of the study reported on in this paper was to explore how teachers and students manifest social presence in the web-based synchronous secondary classroom (WBSSC. Data were collected using structured and unstructured observations of twelve online recordings of web-based synchronous classes in the province of Newfoundland and Labrador, Canada. Structured observations were guided by an instrument developed by Rourke, Anderson, Garrison and Archer (2001 for identifying and measuring social presence in an online context. Findings revealed that teachers and students relied on different tools when providing affective, interactive and cohesive responses related to social presence. Manifestations of social presence by the teachers occurred through use of two-way audio whereas students relied on text-based Direct Messaging. Expressions of social presence by the students and teachers occurred most often in a context of digressions that drew attention away from the delivery of content. In addition, students demonstrated social presence using discourse conventions transferred from informal social contexts of instant messaging such as ICQ and MSN. Résumé : L’objet de la présente étude consistait à examiner de quelle façon les enseignants et les étudiants font preuve de présence sociale dans les salles de classe synchrones en ligne du secondaire. Des données ont été recueillies au moyen d’observations structurées et non structurées provenant de douze enregistrements en ligne de classes synchrones accessibles par Internet dans la province de Terre-Neuve et Labrador, Canada. Les observations structurées ont été dirigées au moyen d’un instrument développé par Rourke, Anderson, Garrison, et Archer (2001 afin d’identifier et de mesurer la présence sociale en ligne. Les résultats démontrent que les enseignants et les élèves utilisent des outils différents pour offrir des réponses affectives, interactives et homogènes li

A secure communication scheme based generalized function projective synchronization of a new 5D hyperchaotic system

International Nuclear Information System (INIS)

Wu, Xiangjun; Fu, Zhengye; Kurths, Jürgen

2015-01-01

In this paper, a new five-dimensional hyperchaotic system is proposed based on the Lü hyperchaotic system. Some of its basic dynamical properties, such as equilibria, Lyapunov exponents, bifurcations and various attractors are investigated. Furthermore, a new secure communication scheme based on generalized function projective synchronization (GFPS) of this hyperchaotic system with an uncertain parameter is presented. The communication scheme is composed of the modulation, the chaotic receiver, the chaotic transmitter and the demodulation. The modulation mechanism is to modulate the message signal into the system parameter. Then the chaotic signals are sent to the receiver via a public channel. In the receiver end, by designing the controllers and the parameter update rule, GFPS between the transmitter and receiver systems is achieved and the unknown parameter is estimated simultaneously. The message signal can be finally recovered by the identified parameter and the corresponding demodulation method. There is no any limitation on the message size. Numerical simulations are performed to show the validity and feasibility of the presented secure communication scheme. (paper)

A Self-Stabilizing Distributed Clock Synchronization Protocol for Arbitrary Digraphs

Science.gov (United States)

Malekpour, Mahyar R.

2011-01-01

This report presents a self-stabilizing distributed clock synchronization protocol in the absence of faults in the system. It is focused on the distributed clock synchronization of an arbitrary, non-partitioned digraph ranging from fully connected to 1-connected networks of nodes while allowing for differences in the network elements. This protocol does not rely on assumptions about the initial state of the system, other than the presence of at least one node, and no central clock or a centrally generated signal, pulse, or message is used. Nodes are anonymous, i.e., they do not have unique identities. There is no theoretical limit on the maximum number of participating nodes. The only constraint on the behavior of the node is that the interactions with other nodes are restricted to defined links and interfaces. We present an outline of a deductive proof of the correctness of the protocol. A model of the protocol was mechanically verified using the Symbolic Model Verifier (SMV) for a variety of topologies. Results of the mechanical proof of the correctness of the protocol are provided. The model checking results have verified the correctness of the protocol as they apply to the networks with unidirectional and bidirectional links. In addition, the results confirm the claims of determinism and linear convergence. As a result, we conjecture that the protocol solves the general case of this problem. We also present several variations of the protocol and discuss that this synchronization protocol is indeed an emergent system.

Application of a Tsunami Warning Message Metric to refine NOAA NWS Tsunami Warning Messages

Science.gov (United States)

Gregg, C. E.; Johnston, D.; Sorensen, J.; Whitmore, P.

2013-12-01

In 2010, the U.S. National Weather Service (NWS) funded a three year project to integrate social science into their Tsunami Program. One of three primary requirements of the grant was to make improvements to tsunami warning messages of the NWS' two Tsunami Warning Centers- the West Coast/Alaska Tsunami Warning Center (WCATWC) in Palmer, Alaska and the Pacific Tsunami Warning Center (PTWC) in Ewa Beach, Hawaii. We conducted focus group meetings with a purposive sample of local, state and Federal stakeholders and emergency managers in six states (AK, WA, OR, CA, HI and NC) and two US Territories (US Virgin Islands and American Samoa) to qualitatively asses information needs in tsunami warning messages using WCATWC tsunami messages for the March 2011 Tohoku earthquake and tsunami event. We also reviewed research literature on behavioral response to warnings to develop a tsunami warning message metric that could be used to guide revisions to tsunami warning messages of both warning centers. The message metric is divided into categories of Message Content, Style, Order and Formatting and Receiver Characteristics. A message is evaluated by cross-referencing the message with the operational definitions of metric factors. Findings are then used to guide revisions of the message until the characteristics of each factor are met. Using findings from this project and findings from a parallel NWS Warning Tiger Team study led by T. Nicolini, the WCATWC implemented the first of two phases of revisions to their warning messages in November 2012. A second phase of additional changes, which will fully implement the redesign of messages based on the metric, is in progress. The resulting messages will reflect current state-of-the-art knowledge on warning message effectiveness. Here we present the message metric; evidence-based rational for message factors; and examples of previous, existing and proposed messages.

The Influence of Group Formation on Learner Participation, Language Complexity, and Corrective Behaviour in Synchronous Written Chat as Part of Academic German Studies

Science.gov (United States)

Fredriksson, Christine

2015-01-01

Synchronous written chat and instant messaging are tools which have been used and explored in online language learning settings for at least two decades. Research literature has shown that such tools give second language (L2) learners opportunities for language learning, e.g. , the interaction in real time with peers and native speakers, the…

GOC-TX: A Reliable Ticket Synchronization Application for the Open Science Grid

Science.gov (United States)

Hayashi, Soichi; Gopu, Arvind; Quick, Robert

2011-12-01

One of the major operational issues faced by large multi-institutional collaborations is permitting its users and support staff to use their native ticket tracking environment while also exchanging these tickets with collaborators. After several failed attempts at email-parser based ticket exchanges, the OSG Operations Group has designed a comprehensive ticket synchronizing application. The GOC-TX application uses web-service interfaces offered by various commercial, open source and other homegrown ticketing systems, to synchronize tickets between two or more of these systems. GOC-TX operates independently from any ticketing system. It can be triggered by one ticketing system via email, active messaging, or a web-services call to check for current sync-status, pull applicable recent updates since prior synchronizations to the source ticket, and apply the updates to a destination ticket. The currently deployed production version of GOC-TX is able to synchronize tickets between the Numara Footprints ticketing system used by the OSG and the following systems: European Grid Initiative's system Global Grid User Support (GGUS) and the Request Tracker (RT) system used by Brookhaven. Additional interfaces to the BMC Remedy system used by Fermilab, and to other instances of RT used by other OSG partners, are expected to be completed in summer 2010. A fully configurable open source version is expected to be made available by early autumn 2010. This paper will cover the structure of the GOC-TX application, its evolution, and the problems encountered by OSG Operations group with ticket exchange within the OSG Collaboration.

GOC-TX: A Reliable Ticket Synchronization Application for the Open Science Grid

International Nuclear Information System (INIS)

Hayashi, Soichi; Gopu, Arvind; Quick, Robert

2011-01-01

One of the major operational issues faced by large multi-institutional collaborations is permitting its users and support staff to use their native ticket tracking environment while also exchanging these tickets with collaborators. After several failed attempts at email-parser based ticket exchanges, the OSG Operations Group has designed a comprehensive ticket synchronizing application. The GOC-TX application uses web-service interfaces offered by various commercial, open source and other homegrown ticketing systems, to synchronize tickets between two or more of these systems. GOC-TX operates independently from any ticketing system. It can be triggered by one ticketing system via email, active messaging, or a web-services call to check for current sync-status, pull applicable recent updates since prior synchronizations to the source ticket, and apply the updates to a destination ticket. The currently deployed production version of GOC-TX is able to synchronize tickets between the Numara Footprints ticketing system used by the OSG and the following systems: European Grid Initiative's system Global Grid User Support (GGUS) and the Request Tracker (RT) system used by Brookhaven. Additional interfaces to the BMC Remedy system used by Fermilab, and to other instances of RT used by other OSG partners, are expected to be completed in summer 2010. A fully configurable open source version is expected to be made available by early autumn 2010. This paper will cover the structure of the GOC-TX application, its evolution, and the problems encountered by OSG Operations group with ticket exchange within the OSG Collaboration.

Overview of Cell Synchronization.

Science.gov (United States)

Banfalvi, Gaspar

2017-01-01

The widespread interest in cell synchronization is maintained by the studies of control mechanism involved in cell cycle regulation. During the synchronization distinct subpopulations of cells are obtained representing different stages of the cell cycle. These subpopulations are then used to study regulatory mechanisms of the cycle at the level of macromolecular biosynthesis (DNA synthesis, gene expression, protein synthesis), protein phosphorylation, development of new drugs, etc. Although several synchronization methods have been described, it is of general interest that scientists get a compilation and an updated view of these synchronization techniques. This introductory chapter summarizes: (1) the basic concepts and principal criteria of cell cycle synchronizations, (2) the most frequently used synchronization methods, such as physical fractionation (flow cytometry, dielectrophoresis, cytofluorometric purification), chemical blockade, (3) synchronization of embryonic cells, (4) synchronization at low temperature, (5) comparison of cell synchrony techniques, (6) synchronization of unicellular organisms, and (7) the effect of synchronization on transfection.

A novel sort of adaptive complex synchronizations of two indistinguishable chaotic complex nonlinear models with uncertain parameters and its applications in secure communications

Science.gov (United States)

Mahmoud, Emad E.; Abood, Fatimah S.

In this paper, we will demonstrate the adaptive complex anti-lag synchronization (CALS) of two indistinguishable complex chaotic nonlinear systems with the parameters which are uncertain. The significance of CALS is not advised well in the literature yet. The CALS contains or consolidate two sorts of synchronizations (anti-lag synchronization ALS and lag synchronization LS). The state variable of the master system synchronizes with an alternate state variable of the slave system. Depending on the function of Lyapunov, a plan is orchestrated to achieve CALS of chaotic attractors of complex systems with unverifiable parameters. CALS of two indistinguishable complexes of Lü systems is viewed as, for example, an occasion for affirming the likelihood of the plan exhibited. In physics, we can see complex chaotic systems in numerous different applications, for example, applied sciences or engineering. With a specific end goal to affirm the proposed synchronization plan viability and demonstrate the hypothetical outcomes, we can compute the numerical simulation. The above outcomes will give the hypothetical establishment to the secure communication applications. CALS of complex chaotic systems in which a state variable of the master system synchronizes with an alternate state variable of the slave system is an encouraging sort of synchronization as it contributes excellent security in secure communication. Amid this secure communication, the synchronization between transmitter and collector is shut and message signals are recouped. The encryption and restoration of the signals are simulated numerically.

New type of chaos synchronization in discrete-time systems: the F-M synchronization

Directory of Open Access Journals (Sweden)

Ouannas Adel

2018-04-01

Full Text Available In this paper, a new type of synchronization for chaotic (hyperchaotic maps with different dimensions is proposed. The novel scheme is called F – M synchronization, since it combines the inverse generalized synchronization (based on a functional relationship F with the matrix projective synchronization (based on a matrix M. In particular, the proposed approach enables F – M synchronization with index d to be achieved between n-dimensional drive system map and m-dimensional response system map, where the synchronization index d corresponds to the dimension of the synchronization error. The technique, which exploits nonlinear controllers and Lyapunov stability theory, proves to be effective in achieving the F – M synchronization not only when the synchronization index d equals n or m, but even if the synchronization index d is larger than the map dimensions n and m. Finally, simulation results are reported, with the aim to illustrate the capabilities of the novel scheme proposed herein.

New type of chaos synchronization in discrete-time systems: the F-M synchronization

Science.gov (United States)

Ouannas, Adel; Grassi, Giuseppe; Karouma, Abdulrahman; Ziar, Toufik; Wang, Xiong; Pham, Viet-Thanh

2018-04-01

In this paper, a new type of synchronization for chaotic (hyperchaotic) maps with different dimensions is proposed. The novel scheme is called F - M synchronization, since it combines the inverse generalized synchronization (based on a functional relationship F) with the matrix projective synchronization (based on a matrix M). In particular, the proposed approach enables F - M synchronization with index d to be achieved between n-dimensional drive system map and m-dimensional response system map, where the synchronization index d corresponds to the dimension of the synchronization error. The technique, which exploits nonlinear controllers and Lyapunov stability theory, proves to be effective in achieving the F - M synchronization not only when the synchronization index d equals n or m, but even if the synchronization index d is larger than the map dimensions n and m. Finally, simulation results are reported, with the aim to illustrate the capabilities of the novel scheme proposed herein.

Metropolitan all-pass and inter-city quantum communication network.

Science.gov (United States)

Chen, Teng-Yun; Wang, Jian; Liang, Hao; Liu, Wei-Yue; Liu, Yang; Jiang, Xiao; Wang, Yuan; Wan, Xu; Cai, Wei-Qi; Ju, Lei; Chen, Luo-Kan; Wang, Liu-Jun; Gao, Yuan; Chen, Kai; Peng, Cheng-Zhi; Chen, Zeng-Bing; Pan, Jian-Wei

2010-12-20

We have demonstrated a metropolitan all-pass quantum communication network in field fiber for four nodes. Any two nodes of them can be connected in the network to perform quantum key distribution (QKD). An optical switching module is presented that enables arbitrary 2-connectivity among output ports. Integrated QKD terminals are worked out, which can operate either as a transmitter, a receiver, or even both at the same time. Furthermore, an additional link in another city of 60 km fiber (up to 130 km) is seamless integrated into this network based on a trusted relay architecture. On all the links, we have implemented protocol of decoy state scheme. All of necessary electrical hardware, synchronization, feedback control, network software, execution of QKD protocols are made by tailored designing, which allow a completely automatical and stable running. Our system has been put into operation in Hefei in August 2009, and publicly demonstrated during an evaluation conference on quantum network organized by the Chinese Academy of Sciences on August 29, 2009. Real-time voice telephone with one-time pad encoding between any two of the five nodes (four all-pass nodes plus one additional node through relay) is successfully established in the network within 60 km.

Secure communication based on multi-input multi-output chaotic system with large message amplitude

International Nuclear Information System (INIS)

Zheng, G.; Boutat, D.; Floquet, T.; Barbot, J.P.

2009-01-01

This paper deals with the problem of secure communication based on multi-input multi-output (MIMO) chaotic systems. Single input secure communication based on chaos can be easily extended to multiple ones by some combinations technologies, however all the combined inputs possess the same risk to be broken. In order to reduce this risk, a new secure communication scheme based on chaos with MIMO is discussed in this paper. Moreover, since the amplitude of messages in traditional schemes is limited because it would affect the quality of synchronization, the proposed scheme is also improved into an amplitude-independent one.

On Synchronization Primitive Systems.

Science.gov (United States)

The report studies the question: what synchronization primitive should be used to handle inter-process communication. A formal model is presented...between these synchronization primitives. Although only four synchronization primitives are compared, the general methods can be used to compare other... synchronization primitives. Moreover, in the definitions of these synchronization primitives, conditional branches are explicitly allowed. In addition

Stages of chaotic synchronization.

Science.gov (United States)

Tang, D. Y.; Dykstra, R.; Hamilton, M. W.; Heckenberg, N. R.

1998-09-01

In an experimental investigation of the response of a chaotic system to a chaotic driving force, we have observed synchronization of chaos of the response system in the forms of generalized synchronization, phase synchronization, and lag synchronization to the driving signal. In this paper we compare the features of these forms of synchronized chaos and study their relations and physical origins. We found that different forms of chaotic synchronization could be interpreted as different stages of nonlinear interaction between the coupled chaotic systems. (c) 1998 American Institute of Physics.

Getting Your Message Across: Mobile Phone Text Messaging

Science.gov (United States)

Beecher, Constance C.; Hayungs, Lori

2017-01-01

Want to send a message that 99% of your audience will read? Many Extension professionals are familiar with using social media tools to enhance Extension programming. Extension professionals may be less familiar with the use of mobile phone text-based marketing tools. The purpose of this article is to introduce SMS (short message system) marketing…

Synchronous ethernet and IEEE 1588 in telecoms next generation synchronization networks

CERN Document Server

2013-01-01

This book addresses the multiple technical aspects of the distribution of synchronization in new generation telecommunication networks, focusing in particular on synchronous Ethernet and IEEE1588 technologies. Many packet network engineers struggle with understanding the challenges that precise synchronization distribution can impose on networks. The usual “why”, “when” and particularly “how” can cause problems for many engineers. In parallel to this, some other markets have identical synchronization requirements, but with their own design requirements, generating further questions. This book attempts to respond to the different questions by providing background technical information. Invaluable information on state of-the-art packet network synchronization and timing architectures is provided, as well as an unbiased view on the synchronization technologies that have been internationally standardized over recent years, with the aim of providing the average reader (who is not skilled in the art) wi...

Synchronous monitoring of muscle dynamics and electromyogram

Science.gov (United States)

Zakir Hossain, M.; Grill, Wolfgang

2011-04-01

A non-intrusive novel detection scheme has been implemented to detect the lateral muscle extension, force of the skeletal muscle and the motor action potential (EMG) synchronously. This allows the comparison of muscle dynamics and EMG signals as a basis for modeling and further studies to determine which architectural parameters are most sensitive to changes in muscle activity. For this purpose the transmission time for ultrasonic chirp signal in the frequency range of 100 kHz to 2.5 MHz passing through the muscle under observation and respective motor action potentials are recorded synchronously to monitor and quantify biomechanical parameters related to muscle performance. Additionally an ultrasonic force sensor has been employed for monitoring. Ultrasonic traducers are placed on the skin to monitor muscle expansion. Surface electrodes are placed suitably to pick up the potential for activation of the monitored muscle. Isometric contraction of the monitored muscle is ensured by restricting the joint motion with the ultrasonic force sensor. Synchronous monitoring was initiated by a software activated audio beep starting at zero time of the subsequent data acquisition interval. Computer controlled electronics are used to generate and detect the ultrasonic signals and monitor the EMG signals. Custom developed software and data analysis is employed to analyze and quantify the monitored data. Reaction time, nerve conduction speed, latent period between the on-set of EMG signals and muscle response, degree of muscle activation and muscle fatigue development, rate of energy expenditure and motor neuron recruitment rate in isometric contraction, and other relevant parameters relating to muscle performance have been quantified with high spatial and temporal resolution.

Impulsive Synchronization and Adaptive-Impulsive Synchronization of a Novel Financial Hyperchaotic System

Directory of Open Access Journals (Sweden)

Xiuli Chai

2013-01-01

Full Text Available The impulsive synchronization and adaptive-impulsive synchronization of a novel financial hyperchaotic system are investigated. Based on comparing principle for impulsive functional differential equations, several sufficient conditions for impulsive synchronization are derived, and the upper bounds of impulsive interval for stable synchronization are estimated. Furthermore, a nonlinear adaptive-impulsive control scheme is designed to synchronize the financial system using invariant principle of impulsive dynamical systems. Moreover, corresponding numerical simulations are presented to illustrate the effectiveness and feasibility of the proposed methods.

Application of Synchronous Text-Based Dialogue Systems in Mental Health Interventions: Systematic Review

Science.gov (United States)

Milne, David N

2017-01-01

Background Synchronous written conversations (or “chats”) are becoming increasingly popular as Web-based mental health interventions. Therefore, it is of utmost importance to evaluate and summarize the quality of these interventions. Objective The aim of this study was to review the current evidence for the feasibility and effectiveness of online one-on-one mental health interventions that use text-based synchronous chat. Methods A systematic search was conducted of the databases relevant to this area of research (Medical Literature Analysis and Retrieval System Online [MEDLINE], PsycINFO, Central, Scopus, EMBASE, Web of Science, IEEE, and ACM). There were no specific selection criteria relating to the participant group. Studies were included if they reported interventions with individual text-based synchronous conversations (ie, chat or text messaging) and a psychological outcome measure. Results A total of 24 articles were included in this review. Interventions included a wide range of mental health targets (eg, anxiety, distress, depression, eating disorders, and addiction) and intervention design. Overall, compared with the waitlist (WL) condition, studies showed significant and sustained improvements in mental health outcomes following synchronous text-based intervention, and post treatment improvement equivalent but not superior to treatment as usual (TAU) (eg, face-to-face and telephone counseling). Conclusions Feasibility studies indicate substantial innovation in this area of mental health intervention with studies utilizing trained volunteers and chatbot technologies to deliver interventions. While studies of efficacy show positive post-intervention gains, further research is needed to determine whether time requirements for this mode of intervention are feasible in clinical practice. PMID:28784594

A Modified Differential Coherent Bit Synchronization Algorithm for BeiDou Weak Signals with Large Frequency Deviation.

Science.gov (United States)

Han, Zhifeng; Liu, Jianye; Li, Rongbing; Zeng, Qinghua; Wang, Yi

2017-07-04

BeiDou system navigation messages are modulated with a secondary NH (Neumann-Hoffman) code of 1 kbps, where frequent bit transitions limit the coherent integration time to 1 millisecond. Therefore, a bit synchronization algorithm is necessary to obtain bit edges and NH code phases. In order to realize bit synchronization for BeiDou weak signals with large frequency deviation, a bit synchronization algorithm based on differential coherent and maximum likelihood is proposed. Firstly, a differential coherent approach is used to remove the effect of frequency deviation, and the differential delay time is set to be a multiple of bit cycle to remove the influence of NH code. Secondly, the maximum likelihood function detection is used to improve the detection probability of weak signals. Finally, Monte Carlo simulations are conducted to analyze the detection performance of the proposed algorithm compared with a traditional algorithm under the CN0s of 20~40 dB-Hz and different frequency deviations. The results show that the proposed algorithm outperforms the traditional method with a frequency deviation of 50 Hz. This algorithm can remove the effect of BeiDou NH code effectively and weaken the influence of frequency deviation. To confirm the feasibility of the proposed algorithm, real data tests are conducted. The proposed algorithm is suitable for BeiDou weak signal bit synchronization with large frequency deviation.

Pinning-controlled synchronization of complex networks with bounded or unbounded synchronized regions

International Nuclear Information System (INIS)

Yan-Li, Zou; Guan-Rong, Chen

2009-01-01

This paper studies pinning-controlled synchronization of complex networks with bounded or unbounded synchronized regions. To study a state-feedback pinning-controlled network with N nodes, it first converts the controlled network to an extended network of N+1 nodes without controls. It is shown that the controlled synchronizability of the given network is determined by the real part of the smallest nonzero eigenvalue of the coupling matrix of its extended network when the synchronized region is unbounded; but it is determined by the ratio of the real parts of the largest and the smallest nonzero eigenvalues of the coupling matrix when the synchronized region is bounded. Both theoretical analysis and numerical simulation show that the portion of controlled nodes has no critical values when the synchronized region is unbounded, but it has a critical value when the synchronized region is bounded. In the former case, therefore, it is possible to control the network to achieve synchronization by pinning only one node. In the latter case, the network can achieve controlled synchronization only when the portion of controlled nodes is larger than the critical value. (general)

Unified Internet Messaging

OpenAIRE

Healy, Paul; Barber, Declan

2015-01-01

As telephony services, mobile services and internet services continue to converge, the prospect of providing Unified Messaging and even Unified Communications becomes increasingly achievable. This paper discusses the growing importance of IP-based networks to Unified Messaging developments and examines some of the key services and protocols that are likely to make Unified Messaging more widely available. In this initial paper, we limit ourselves initially to the unification of text-based mess...

Message-driven factors influencing opening and forwarding of mobile advertising messages

OpenAIRE

Sanz Blas, Silvia; Ruiz Mafé, Carla; Martí Parreño, José

2015-01-01

This work aims to analyse the influence of message-driven factors -informativeness, ubiquity, frequency and personalization- on consumer attitude and behaviour -opening and forwarding- towards mobile advertising messages. A theoretical model was developed and empirically tested using a sample of 355 Spanish teenager mobile users. Findings show that frequency is the dimension accounting the most -and significantly- of the four message-driven factors analysed on attitude toward mobile advertisi...

Synchronization on effective networks

International Nuclear Information System (INIS)

Zhou Tao; Zhao Ming; Zhou Changsong

2010-01-01

The study of network synchronization has attracted increasing attentionrecently. In this paper, we strictly define a class of networks, namely effective networks, which are synchronizable and orientable networks. We can prove that all the effective networks with the same size have the same spectra, and are of the best synchronizability according to the master stability analysis. However, it is found that the synchronization time for different effective networks can be quite different. Further analysis shows that the key ingredient affecting the synchronization time is the maximal depth of an effective network: the larger depth results in a longer synchronization time. The secondary factor is the number of links. The increasing number of links connecting nodes in the same layer (horizontal links) will lead to longer synchronization time, whereas the increasing number of links connecting nodes in neighboring layers (vertical links) will accelerate the synchronization. Our analysis of the relationship between the structure and synchronization properties of the original and effective networks shows that the purely directed effective network can provide an approximation of the original weighted network with normalized input strength. Our findings provide insights into the roles of depth, horizontal and vertical links in the synchronizing process, and suggest that the spectral analysis is helpful yet insufficient for the comprehensive understanding of network synchronization.

Synchronization on effective networks

Energy Technology Data Exchange (ETDEWEB)

Zhou Tao [Web Sciences Center, University of Electronic Science and Technology of China, Chengdu 610054 (China); Zhao Ming [Department of Modern Physics, University of Science and Technology of China, Hefei 230026 (China); Zhou Changsong, E-mail: cszhou@hkbu.edu.h [Department of Physics, Hong Kong Baptist University, Kowloon Tong (Hong Kong)

2010-04-15

The study of network synchronization has attracted increasing attentionrecently. In this paper, we strictly define a class of networks, namely effective networks, which are synchronizable and orientable networks. We can prove that all the effective networks with the same size have the same spectra, and are of the best synchronizability according to the master stability analysis. However, it is found that the synchronization time for different effective networks can be quite different. Further analysis shows that the key ingredient affecting the synchronization time is the maximal depth of an effective network: the larger depth results in a longer synchronization time. The secondary factor is the number of links. The increasing number of links connecting nodes in the same layer (horizontal links) will lead to longer synchronization time, whereas the increasing number of links connecting nodes in neighboring layers (vertical links) will accelerate the synchronization. Our analysis of the relationship between the structure and synchronization properties of the original and effective networks shows that the purely directed effective network can provide an approximation of the original weighted network with normalized input strength. Our findings provide insights into the roles of depth, horizontal and vertical links in the synchronizing process, and suggest that the spectral analysis is helpful yet insufficient for the comprehensive understanding of network synchronization.

When message-frame fits salient cultural-frame, messages feel more persuasive

OpenAIRE

Uskul, Ayse K.; Oyserman, Daphna

2010-01-01

The present study examines the persuasive effects of tailored health messages comparing those tailored to match (versus not match) both chronic cultural frame and momentarily salient cultural frame. Evidence from two studies (Study 1: n = 72 European Americans; Study 2: n = 48 Asian Americans) supports the hypothesis that message persuasiveness increases when chronic cultural frame, health message tailoring and momentarily salient cultural frame all match. The hypothesis was tested using a me...

Synchronization of chaotic systems

International Nuclear Information System (INIS)

Pecora, Louis M.; Carroll, Thomas L.

2015-01-01

We review some of the history and early work in the area of synchronization in chaotic systems. We start with our own discovery of the phenomenon, but go on to establish the historical timeline of this topic back to the earliest known paper. The topic of synchronization of chaotic systems has always been intriguing, since chaotic systems are known to resist synchronization because of their positive Lyapunov exponents. The convergence of the two systems to identical trajectories is a surprise. We show how people originally thought about this process and how the concept of synchronization changed over the years to a more geometric view using synchronization manifolds. We also show that building synchronizing systems leads naturally to engineering more complex systems whose constituents are chaotic, but which can be tuned to output various chaotic signals. We finally end up at a topic that is still in very active exploration today and that is synchronization of dynamical systems in networks of oscillators

MessageSpace: a messaging system for health research

Science.gov (United States)

Escobar, Rodrigo D.; Akopian, David; Parra-Medina, Deborah; Esparza, Laura

2013-03-01

Mobile Health (mHealth) has emerged as a promising direction for delivery of healthcare services via mobile communication devices such as cell phones. Examples include texting-based interventions for chronic disease monitoring, diabetes management, control of hypertension, smoking cessation, monitoring medication adherence, appointment keeping and medical test result delivery; as well as improving patient-provider communication, health information communication, data collection and access to health records. While existing messaging systems very well support bulk messaging and some polling applications, they are not designed for data collection and processing of health research oriented studies. For that reason known studies based on text-messaging campaigns have been constrained in participant numbers. In order to empower healthcare promotion and education research, this paper presents a system dedicated for healthcare research. It is designed for convenient communication with various study groups, feedback collection and automated processing.

EMI Messaging Guidelines

CERN Document Server

Cons, L.

2011-01-01

Guidelines for potential users of messaging within EMI. The goal is to provide enough practical information so that EMI product teams can start investigating whether using messaging in their products can be beneficial or not.

Content-based intermedia synchronization

Science.gov (United States)

Oh, Dong-Young; Sampath-Kumar, Srihari; Rangan, P. Venkat

1995-03-01

Inter-media synchronization methods developed until now have been based on syntactic timestamping of video frames and audio samples. These methods are not fully appropriate for the synchronization of multimedia objects which may have to be accessed individually by their contents, e.g. content-base data retrieval. We propose a content-based multimedia synchronization scheme in which a media stream is viewed as hierarchial composition of smaller objects which are logically structured based on the contents, and the synchronization is achieved by deriving temporal relations among logical units of media object. content-based synchronization offers several advantages such as, elimination of the need for time stamping, freedom from limitations of jitter, synchronization of independently captured media objects in video editing, and compensation for inherent asynchronies in capture times of video and audio.

Application of Synchronous Text-Based Dialogue Systems in Mental Health Interventions: Systematic Review.

Science.gov (United States)

Hoermann, Simon; McCabe, Kathryn L; Milne, David N; Calvo, Rafael A

2017-07-21

Synchronous written conversations (or "chats") are becoming increasingly popular as Web-based mental health interventions. Therefore, it is of utmost importance to evaluate and summarize the quality of these interventions. The aim of this study was to review the current evidence for the feasibility and effectiveness of online one-on-one mental health interventions that use text-based synchronous chat. A systematic search was conducted of the databases relevant to this area of research (Medical Literature Analysis and Retrieval System Online [MEDLINE], PsycINFO, Central, Scopus, EMBASE, Web of Science, IEEE, and ACM). There were no specific selection criteria relating to the participant group. Studies were included if they reported interventions with individual text-based synchronous conversations (ie, chat or text messaging) and a psychological outcome measure. A total of 24 articles were included in this review. Interventions included a wide range of mental health targets (eg, anxiety, distress, depression, eating disorders, and addiction) and intervention design. Overall, compared with the waitlist (WL) condition, studies showed significant and sustained improvements in mental health outcomes following synchronous text-based intervention, and post treatment improvement equivalent but not superior to treatment as usual (TAU) (eg, face-to-face and telephone counseling). Feasibility studies indicate substantial innovation in this area of mental health intervention with studies utilizing trained volunteers and chatbot technologies to deliver interventions. While studies of efficacy show positive post-intervention gains, further research is needed to determine whether time requirements for this mode of intervention are feasible in clinical practice. ©Simon Hoermann, Kathryn L McCabe, David N Milne, Rafael A Calvo. Originally published in the Journal of Medical Internet Research (http://www.jmir.org), 21.07.2017.

Fast Self-Synchronization between LowVoltage Microgrid and Inverter using Virtual Synchronous Converter

Directory of Open Access Journals (Sweden)

Md Ruhul Amin

2017-12-01

Full Text Available In this paper, a fast self-synchronization known as virtual synchronous converter (VSCon between single-phase microgrid and inverter in low-voltage microgrid, has been developed in Matlab/Simulink. The idea is to any phase locked loop (PLL circuit for inverter-microgrid synchronization in order to improve the synchronization time. As known, it is difficult and lengthy process to tune the PLL gain parameters to reach suitable performance for synchronizing among the voltage, phase-angle and frequency between them. Due to this problem, a fast self synchronization technique is needed in order to minimize the time losses at the microgrid connection. Therefore, the VSCon has been developed which is based on the synchronous generator mathematical model but in virtual environment representation. It has been applied in the inverter control for generating switching pattern to the inverter switches in order to respond to the grid voltage for improve the synchronization. For a prove of concept, several simulation tests in MATLAB models have been conducted, in order to see the effectiveness of this VSCon. First test has been conducted, when a 240V, 50Hz frequency grid source is used for observing the self-synchronization the system with the power flows output. Furthermore, the next test is conducted when the grid frequency is changed from the rated frequency at 50Hz to 51Hz and the result shows the VSCon in inverter control takes nearly 40ms to synchronize to this new frequency value. The test on grid phase-angle delay also been tested when ac grid voltage has 150 phase delay. As from all the results, the improved inverter control with VSCon structure is able to have fast and self-synchronized between the invertergrid connection before the power from the inverter can be transferred.

Synchronization of Multipoint Hoists

Science.gov (United States)

A contractor has conceived an electrohydraulic feedback system that will provide position synchronization of four aircraft cargo hoists. To... synchronized hoist system. Test results show that the feedback system concept provides adequate synchronization control; i.e., the platform pitch and roll

INVESTIGATION OF SINGLE-PASS/DOUBLE-PASS TECHNIQUES ON FRICTION STIR WELDING OF ALUMINIUM

Directory of Open Access Journals (Sweden)

N.A.A. Sathari

2014-12-01

Full Text Available The aim of this research is to study the effects of single-pass/ double-pass techniques on friction stir welding of aluminium. Two pieces of AA1100 with a thickness of 6.0 mm were friction stir welded using a CNC milling machine at rotational speeds of 1400 rpm, 1600 rpm and 1800 rpm respectively for single-pass and double-pass. Microstructure observations of the welded area were studied using an optical microscope. The specimens were tested by using a tensile test and Vickers hardness test to evaluate their mechanical properties. The results indicated that, at low rotational speed, defects such as ‘surface lack of fill’ and tunnels in the welded area contributed to a decrease in mechanical properties. Welded specimens using double-pass techniques show increasing values of tensile strength and hardness. From this investigation it is found that the best parameters of FSW welded aluminium AA1100 plate were those using double-pass techniques that produce mechanically sound joints with a hardness of 56.38 HV and 108 MPa strength at 1800 rpm compared to the single-pass technique. Friction stir welding, single-pass/ double-pass techniques, AA1100, microstructure, mechanical properties.

On Position Sensorless Control for Permanent Magnet Synchronous Motor Based on a New Sliding Mode Observer

Directory of Open Access Journals (Sweden)

Qixin Zhu

2014-10-01

Full Text Available For the problems of buffeting and phase delay in traditional rotor detection in sensorless vector control of permanent magnet synchronous motor (PMSM, the Sigmoid function is proposed to replace sign function and the approach of piecewise linearization is proposed to compensate phase delay. To the problem that the output of traditional low pass filter contains high- order harmonic, two-stage filter including traditional low-pass filter and Kalman filter is proposed in this paper. Based on the output of traditional first-order low-pass filter, the Kalman filter is used to get modified back-EMF. The phase-locked loop control of rotor position is adopted to estimate motor position and speed. A Matlab/Simulink simulation model of PMSM position servo control system is established. The simulation analysis of the new sliding mode observer’s back-EMF detection, position and speed estimation, load disturbance and dynamic process are carried out respectively. Simulation results verify feasibility of the new sliding mode observer algorithm.

Messages about appearance, food, weight and exercise in "tween" television.

Science.gov (United States)

Simpson, Courtney C; Kwitowski, Melissa; Boutte, Rachel; Gow, Rachel W; Mazzeo, Suzanne E

2016-12-01

Tweens (children ages ~8-14years) are a relatively recently defined age group, increasingly targeted by marketers. Individuals in this age group are particularly vulnerable to opinions and behaviors presented in media messages, given their level of cognitive and social development. However, little research has examined messages about appearance, food, weight, and exercise in television specifically targeting tweens, despite the popularity of this media type among this age group. This study used a content analytic approach to explore these messages in the five most popular television shows for tweens on the Disney Channel (as of 2015). Using a multiple-pass approach, relevant content in episodes from the most recently completed seasons of each show was coded. Appearance related incidents occurred in every episode; these most frequently mentioned attractiveness/beauty. Food related incidents were also present in every episode; typically, these situations were appearance and weight neutral. Exercise related incidents occurred in 53.3% of episodes; the majority expressed resistance to exercise. Weight related incidents occurred in 40.0% of the episodes; the majority praised the muscular ideal. Women were more likely to initiate appearance incidents, and men were more likely to initiate exercise incidents. These results suggest that programs specifically marketed to tweens reinforce appearance ideals, including stereotypes about female attractiveness and male athleticism, two constructs linked to eating pathology and body dissatisfaction. Given the developmental vulnerability of the target group, these findings are concerning, and highlight potential foci for prevention programming, including media literacy, for tweens. Copyright © 2016 Elsevier Ltd. All rights reserved.

Positive mood can increase or decrease message scrutiny: the hedonic contingency view of mood and message processing.

Science.gov (United States)

Wegener, D T; Petty, R E; Smith, S M

1995-07-01

Currently dominant explanations of mood effects on persuasive message processing (i.e., cognitive capacity and feelings as information) predict that happy moods lead to less message scrutiny than neutral or sad moods. The hedonic contingency view (D. T. Wegener & R. E. Petty, 1994) predicts that happy moods can sometimes be associated with greater message processing activity because people in a happy mood are more attentive than neutral or sad people to the hedonic consequences of their actions. Consistent with this view, Experiment 1 finds that a happy mood can lead to greater message scrutiny than a neutral mood when the message is not mood threatening. Experiment 2 finds that a happy mood leads to greater message scrutiny than a sad mood when an uplifting message is encountered, but to less message scrutiny when a depressing message is encountered.

CDC MessageWorks: Designing and Validating a Social Marketing Tool to Craft and Defend Effective Messages.

Science.gov (United States)

Cole, Galen E; Keller, Punam A; Reynolds, Jennifer; Schaur, Michelle; Krause, Diane

2016-03-01

The Centers for Disease Control and Prevention's Division of Cancer Prevention and Control, in partnership with Oak Ridge Associated Universities, designed an online social marketing strategy tool, MessageWorks, to help health communicators effectively formulate messages aimed at changing health behaviors and evaluate message tactics and audience characteristics. MessageWorks is based on the advisor for risk communication model that identifies 10 variables that can be used to predict target audience intentions to comply with health recommendations. This article discusses the value of the MessageWorks tool to health communicators and to the field of social marketing by (1) describing the scientific evidence supporting use of MessageWorks to improve health communication practice and (2) summarizing how to use MessageWorks and interpret the results it produces.

Thrust Reduction of Magnetic Levitation Vehicle Driven by Long Stator Linear Synchronous Motor

Directory of Open Access Journals (Sweden)

Wan-Tsun Tseng

2013-01-01

Full Text Available The propulsion technology of long stator linear synchronous motors is used to drive high-speed maglev trains. The linear synchronous motor stator is divided into sections placed on guideway. The electric power supplies to stator sections in which the train just passes in change-step mode for long-distance operation. However, a thrust drop will be caused by change-step machinery for driving magnetic vehicle. According to the train speed and vehicle data, the change-step mode has three types of operation, namely premature commutation, simultaneous commutation, and late commutation. Each type of operation has a different thrust drop which can be affected by several parameters such as jerk, running speed, motor section length, and vehicle data. This paper focuses on determining the thrust drop of the change-step mode. The study results of this paper can be used to improve the operation system of high-speed maglev trains.

Passing and Catching in Rugby.

Science.gov (United States)

Namudu, Mike M.

This booklet contains the fundamentals for rugby at the primary school level. It deals primarily with passing and catching the ball. It contains instructions on (1) holding the ball for passing, (2) passing the ball to the left--standing, (3) passing the ball to the left--running, (4) making a switch pass, (5) the scrum half's normal pass, (6) the…

An analysis of patient-provider secure messaging at two Veterans Health Administration medical centers: message content and resolution through secure messaging.

Science.gov (United States)

Shimada, Stephanie L; Petrakis, Beth Ann; Rothendler, James A; Zirkle, Maryan; Zhao, Shibei; Feng, Hua; Fix, Gemmae M; Ozkaynak, Mustafa; Martin, Tracey; Johnson, Sharon A; Tulu, Bengisu; Gordon, Howard S; Simon, Steven R; Woods, Susan S

2017-09-01

We sought to understand how patients and primary care teams use secure messaging (SM) to communicate with one another by analyzing secure message threads from 2 Department of Veterans Affairs facilities. We coded 1000 threads of SM communication sampled from 40 primary care teams. Most threads (94.5%) were initiated by patients (90.4%) or caregivers (4.1%); only 5.5% were initiated by primary care team members proactively reaching out to patients. Medication renewals and refills (47.2%), scheduling requests (17.6%), medication issues (12.9%), and health issues (12.7%) were the most common patient-initiated requests, followed by referrals (7.0%), administrative issues (6.5%), test results (5.4%), test issues (5.2%), informing messages (4.9%), comments about the patient portal or SM (4.1%), appreciation (3.9%), self-reported data (2.8%), life issues (1.5%), and complaints (1.5%). Very few messages were clinically urgent (0.7%) or contained other potentially challenging content. Message threads were mostly short (2.7 messages), comprising an average of 1.35 discrete content types. A substantial proportion of issues (24.2%) did not show any evidence of being resolved through SM. Time to response and extent of resolution via SM varied by message content. Proactive SM use by teams varied, but was most often for test results (32.7%), medication-related issues (21.8%), medication renewals (16.4%), or scheduling issues (18.2%). The majority of messages were transactional and initiated by patients or caregivers. Not all content categories were fully addressed over SM. Further education and training for both patients and clinical teams could improve the quality and efficiency of SM communication. Published by Oxford University Press on behalf of the American Medical Informatics Association 2017. This work is written by US Government employees and is in the public domain in the United States.

CDC MessageWorks: Designing and Validating a Social Marketing Tool to Craft and Defend Effective Messages

Science.gov (United States)

Cole, Galen E.; Keller, Punam A.; Reynolds, Jennifer; Schaur, Michelle; Krause, Diane

2016-01-01

The Centers for Disease Control and Prevention’s Division of Cancer Prevention and Control, in partnership with Oak Ridge Associated Universities, designed an online social marketing strategy tool, MessageWorks, to help health communicators effectively formulate messages aimed at changing health behaviors and evaluate message tactics and audience characteristics. MessageWorks is based on the advisor for risk communication model that identifies 10 variables that can be used to predict target audience intentions to comply with health recommendations. This article discusses the value of the MessageWorks tool to health communicators and to the field of social marketing by (1) describing the scientific evidence supporting use of MessageWorks to improve health communication practice and (2) summarizing how to use MessageWorks and interpret the results it produces. PMID:26877714

Cell Division Synchronization

Science.gov (United States)

The report summarizes the progress in the design and construction of automatic equipment for synchronizing cell division in culture by periodic...Concurrent experiments in hypothermic synchronization of algal cell division are reported.

Synchronization dynamics of two different dynamical systems

International Nuclear Information System (INIS)

Luo, Albert C.J.; Min Fuhong

2011-01-01

Highlights: → Synchronization dynamics of two distinct dynamical systems. → Synchronization, de-synchronization and instantaneous synchronization. → A controlled pendulum synchronizing with the Duffing oscillator. → Synchronization invariant set. → Synchronization parameter map. - Abstract: In this paper, synchronization dynamics of two different dynamical systems is investigated through the theory of discontinuous dynamical systems. The necessary and sufficient conditions for the synchronization, de-synchronization and instantaneous synchronization (penetration or grazing) are presented. Using such a synchronization theory, the synchronization of a controlled pendulum with the Duffing oscillator is systematically discussed as a sampled problem, and the corresponding analytical conditions for the synchronization are presented. The synchronization parameter study is carried out for a better understanding of synchronization characteristics of the controlled pendulum and the Duffing oscillator. Finally, the partial and full synchronizations of the controlled pendulum with periodic and chaotic motions are presented to illustrate the analytical conditions. The synchronization of the Duffing oscillator and pendulum are investigated in order to show the usefulness and efficiency of the methodology in this paper. The synchronization invariant domain is obtained. The technique presented in this paper should have a wide spectrum of applications in engineering. For example, this technique can be applied to the maneuvering target tracking, and the others.

FPGA based fast synchronous serial multi-wire links synchronization

Science.gov (United States)

Pozniak, Krzysztof T.

2013-10-01

The paper debates synchronization method of multi-wire, serial link of constant latency, by means of pseudo-random numbers generators. The solution was designed for various families of FPGA circuits. There were debated synchronization algorithm and functional structure of parameterized transmitter and receiver modules. The modules were realized in VHDL language in a behavioral form.

A Weld Position Recognition Method Based on Directional and Structured Light Information Fusion in Multi-Layer/Multi-Pass Welding

Directory of Open Access Journals (Sweden)

Jinle Zeng

2018-01-01

Full Text Available Multi-layer/multi-pass welding (MLMPW technology is widely used in the energy industry to join thick components. During automatic welding using robots or other actuators, it is very important to recognize the actual weld pass position using visual methods, which can then be used not only to perform reasonable path planning for actuators, but also to correct any deviations between the welding torch and the weld pass position in real time. However, due to the small geometrical differences between adjacent weld passes, existing weld position recognition technologies such as structured light methods are not suitable for weld position detection in MLMPW. This paper proposes a novel method for weld position detection, which fuses various kinds of information in MLMPW. First, a synchronous acquisition method is developed to obtain various kinds of visual information when directional light and structured light sources are on, respectively. Then, interferences are eliminated by fusing adjacent images. Finally, the information from directional and structured light images is fused to obtain the 3D positions of the weld passes. Experiment results show that each process can be done in 30 ms and the deviation is less than 0.6 mm. The proposed method can be used for automatic path planning and seam tracking in the robotic MLMPW process as well as electron beam freeform fabrication process.

A Weld Position Recognition Method Based on Directional and Structured Light Information Fusion in Multi-Layer/Multi-Pass Welding.

Science.gov (United States)

Zeng, Jinle; Chang, Baohua; Du, Dong; Wang, Li; Chang, Shuhe; Peng, Guodong; Wang, Wenzhu

2018-01-05

Multi-layer/multi-pass welding (MLMPW) technology is widely used in the energy industry to join thick components. During automatic welding using robots or other actuators, it is very important to recognize the actual weld pass position using visual methods, which can then be used not only to perform reasonable path planning for actuators, but also to correct any deviations between the welding torch and the weld pass position in real time. However, due to the small geometrical differences between adjacent weld passes, existing weld position recognition technologies such as structured light methods are not suitable for weld position detection in MLMPW. This paper proposes a novel method for weld position detection, which fuses various kinds of information in MLMPW. First, a synchronous acquisition method is developed to obtain various kinds of visual information when directional light and structured light sources are on, respectively. Then, interferences are eliminated by fusing adjacent images. Finally, the information from directional and structured light images is fused to obtain the 3D positions of the weld passes. Experiment results show that each process can be done in 30 ms and the deviation is less than 0.6 mm. The proposed method can be used for automatic path planning and seam tracking in the robotic MLMPW process as well as electron beam freeform fabrication process.

Synchronizing Strategies under Partial Observability

DEFF Research Database (Denmark)

Larsen, Kim Guldstrand; Laursen, Simon; Srba, Jiri

2014-01-01

Embedded devices usually share only partial information about their current configurations as the communication bandwidth can be restricted. Despite this, we may wish to bring a failed device into a given predetermined configuration. This problem, also known as resetting or synchronizing words, has...... been intensively studied for systems that do not provide any information about their configurations. In order to capture more general scenarios, we extend the existing theory of synchronizing words to synchronizing strategies, and study the synchronization, short-synchronization and subset...

Message framing in social networking sites.

Science.gov (United States)

Kao, Danny Tengti; Chuang, Shih-Chieh; Wang, Sui-Min; Zhang, Lei

2013-10-01

Online social networking sites represent significant new opportunities for Internet advertisers. However, results based on the real world cannot be generalized to all virtual worlds. In this research, the moderating effects of need for cognition (NFC) and knowledge were applied to examine the impact of message framing on attitudes toward social networking sites. A total of 216 undergraduates participated in the study. Results reveal that for social networking sites, while high-NFC individuals form more favorable attitudes toward negatively framed messages than positively framed messages, low-NFC individuals form more favorable attitudes toward positively framed messages than negatively framed messages. In addition, low-knowledge individuals demonstrate more favorable attitudes toward negatively framed messages than positively framed messages; however, the framing effect does not differentially affect the attitudes of high-knowledge individuals. Furthermore, the framing effect does not differentially affect the attitudes of high-NFC individuals with high knowledge. In contrast, low-NFC individuals with low knowledge hold more favorable attitudes toward positively framed messages than negatively framed messages.

Biologically Inspired Intercellular Slot Synchronization

Directory of Open Access Journals (Sweden)

Alexander Tyrrell

2009-01-01

Full Text Available The present article develops a decentralized interbase station slot synchronization algorithm suitable for cellular mobile communication systems. The proposed cellular firefly synchronization (CelFSync algorithm is derived from the theory of pulse-coupled oscillators, common to describe synchronization phenomena in biological systems, such as the spontaneous synchronization of fireflies. In order to maintain synchronization among base stations (BSs, even when there is no direct link between adjacent BSs, some selected user terminals (UTs participate in the network synchronization process. Synchronization emerges by exchanging two distinct synchronization words, one transmitted by BSs and the other by active UTs, without any a priori assumption on the initial timing misalignments of BSs and UTs. In large-scale networks with inter-BS site distances up to a few kilometers, propagation delays severely affect the attainable timing accuracy of CelFSync. We show that by an appropriate combination of CelFSync with the timing advance procedure, which aligns uplink transmission of UTs to arrive simultaneously at the BS, a timing accuracy within a fraction of the inter-BS propagation delay is retained.

Exploiting Schemas in Data Synchronization

DEFF Research Database (Denmark)

Foster, J. Nathan; Greenwald, Michael B.; Kirkegaard, Christian

2005-01-01

Increased reliance on optimistic data replication has led to burgeoning interest in tools and frameworks for disconnected updates to replicated data.We have implemented a generic synchronization framework, called HARMONY, that can be used to build state-based synchronizers for a wide variety...... of tree-structureddata formats. A novel feature of this framework is that the synchronization process - in particular, the recognition of conflicts - is driven by the schema of the structures being synchronized.We formalize HARMONY's synchronization algorithm, state a simple and intuitive specification......, and illustrate, using simple address books as a case study, how it can be used to synchronize trees representing a variety of specific forms of applicationdata, including sets, records, tuples, and relations....

Improving the Effectiveness of Fundraising Messages: The Impact of Charity Goal Attainment, Message Framing, and Evidence on Persuasion

Science.gov (United States)

Das, Enny; Kerkhof, Peter; Kuiper, Joyce

2008-01-01

This experimental study assessed the effectiveness of fundraising messages. Based on recent findings regarding the effects of message framing and evidence, effective fundraising messages should combine abstract, statistical information with a negative message frame and anecdotal evidence with a positive message frame. In addition, building on…

Starting Off on the Best Foot: A Review of Message Framing and Message Tailoring, and Recommendations for the Comprehensive Messaging Strategy for Sustained Behavior Change.

Science.gov (United States)

Pope, J Paige; Pelletier, Luc; Guertin, Camille

2018-09-01

Health promotion programs represent a salient means through which physical activity promoters can cultivate positive health behavior change and maintenance. The messages communicated within these programs serve as an essential component as they are often used to convey valuable information, resources, or tools that facilitate health behavior initiation and sustained engagement. Identifying the most effective way to communicate health promotion information is, therefore, of considerable importance to ensuring that people not only attend to these messages, but also connect with and internalize the information conveyed within them. This paper was written to (1) summarize and evaluate the most prominent reviewed research approaches of message framing and tailoring to message design; and (2) offer a comprehensive messaging strategy to promote sustained health behavior change. A review of the literature demonstrated that a messaging strategy that has consistently led to healthy behavior change has yet to be identified. Furthermore, scholars have articulated that a multi-theoretical approach that places emphasis on facilitating motivation and healthy behavior change needs to be employed. Thus, this paper proposes and provides recommendations for employing the Comprehensive Messaging Strategy for Sustained Behavior Change (CMSSBC), which advocates tailoring messages to peoples' stage of change and framing them to focus on self-determined motives and intrinsic goals.

Survey of Instant Messaging Applications Encryption Methods

OpenAIRE

Kabakuş, Abdullah; Kara, Resul

2015-01-01

Instant messaging applications has already taken the place of traditional Short Messaging Service (SMS) and Multimedia Messaging Service (MMS) due to their popularity and usage easement they provide. Users of instant messaging applications are able to send both text and audio messages, different types of attachments such as photos, videos, contact information to their contacts in real time. Because of instant messaging applications use internet instead of Short Message Service Technical Reali...

Impact of Cultural Exposure and Message Framing on Oral Health Behavior: Exploring the Role of Message Memory.

Science.gov (United States)

Brick, Cameron; McCully, Scout N; Updegraff, John A; Ehret, Phillip J; Areguin, Maira A; Sherman, David K

2016-10-01

Health messages are more effective when framed to be congruent with recipient characteristics, and health practitioners can strategically choose message features to promote adherence to recommended behaviors. We present exposure to US culture as a moderator of the impact of gain-frame versus loss-frame messages. Since US culture emphasizes individualism and approach orientation, greater cultural exposure was expected to predict improved patient choices and memory for gain-framed messages, whereas individuals with less exposure to US culture would show these advantages for loss-framed messages. 223 participants viewed a written oral health message in 1 of 3 randomized conditions-gain-frame, loss-frame, or no-message control-and were given 10 flosses. Cultural exposure was measured with the proportions of life spent and parents born in the US. At baseline and 1 week later, participants completed recall tests and reported recent flossing behavior. Message frame and cultural exposure interacted to predict improved patient decisions (increased flossing) and memory maintenance for the health message over 1 week; for example, those with low cultural exposure who saw a loss-frame message flossed more. Incongruent messages led to the same flossing rates as no message. Memory retention did not explain the effect of message congruency on flossing. Flossing behavior was self-reported. Cultural exposure may only have practical application in either highly individualistic or collectivistic countries. In health care settings where patients are urged to follow a behavior, asking basic demographic questions could allow medical practitioners to intentionally communicate in terms of gains or losses to improve patient decision making and treatment adherence. © The Author(s) 2015.

Supporting Beacon and Event-Driven Messages in Vehicular Platoons through Token-Based Strategies.

Science.gov (United States)

Balador, Ali; Uhlemann, Elisabeth; Calafate, Carlos T; Cano, Juan-Carlos

2018-03-23

Timely and reliable inter-vehicle communications is a critical requirement to support traffic safety applications, such as vehicle platooning. Furthermore, low-delay communications allow the platoon to react quickly to unexpected events. In this scope, having a predictable and highly effective medium access control (MAC) method is of utmost importance. However, the currently available IEEE 802.11p technology is unable to adequately address these challenges. In this paper, we propose a MAC method especially adapted to platoons, able to transmit beacons within the required time constraints, but with a higher reliability level than IEEE 802.11p, while concurrently enabling efficient dissemination of event-driven messages. The protocol circulates the token within the platoon not in a round-robin fashion, but based on beacon data age, i.e., the time that has passed since the previous collection of status information, thereby automatically offering repeated beacon transmission opportunities for increased reliability. In addition, we propose three different methods for supporting event-driven messages co-existing with beacons. Analysis and simulation results in single and multi-hop scenarios showed that, by providing non-competitive channel access and frequent retransmission opportunities, our protocol can offer beacon delivery within one beacon generation interval while fulfilling the requirements on low-delay dissemination of event-driven messages for traffic safety applications.

Supporting Beacon and Event-Driven Messages in Vehicular Platoons through Token-Based Strategies

Directory of Open Access Journals (Sweden)

Ali Balador

2018-03-01

Full Text Available Timely and reliable inter-vehicle communications is a critical requirement to support traffic safety applications, such as vehicle platooning. Furthermore, low-delay communications allow the platoon to react quickly to unexpected events. In this scope, having a predictable and highly effective medium access control (MAC method is of utmost importance. However, the currently available IEEE 802.11p technology is unable to adequately address these challenges. In this paper, we propose a MAC method especially adapted to platoons, able to transmit beacons within the required time constraints, but with a higher reliability level than IEEE 802.11p, while concurrently enabling efficient dissemination of event-driven messages. The protocol circulates the token within the platoon not in a round-robin fashion, but based on beacon data age, i.e., the time that has passed since the previous collection of status information, thereby automatically offering repeated beacon transmission opportunities for increased reliability. In addition, we propose three different methods for supporting event-driven messages co-existing with beacons. Analysis and simulation results in single and multi-hop scenarios showed that, by providing non-competitive channel access and frequent retransmission opportunities, our protocol can offer beacon delivery within one beacon generation interval while fulfilling the requirements on low-delay dissemination of event-driven messages for traffic safety applications.

Degree sequence in message transfer

Science.gov (United States)

Yamuna, M.

2017-11-01

Message encryption is always an issue in current communication scenario. Methods are being devised using various domains. Graphs satisfy numerous unique properties which can be used for message transfer. In this paper, I propose a message encryption method based on degree sequence of graphs.

Asynchronized synchronous machines

CERN Document Server

Botvinnik, M M

1964-01-01

Asynchronized Synchronous Machines focuses on the theoretical research on asynchronized synchronous (AS) machines, which are "hybrids” of synchronous and induction machines that can operate with slip. Topics covered in this book include the initial equations; vector diagram of an AS machine; regulation in cases of deviation from the law of full compensation; parameters of the excitation system; and schematic diagram of an excitation regulator. The possible applications of AS machines and its calculations in certain cases are also discussed. This publication is beneficial for students and indiv

Model reference adaptive control (MRAC)-based parameter identification applied to surface-mounted permanent magnet synchronous motor

Science.gov (United States)

Zhong, Chongquan; Lin, Yaoyao

2017-11-01

In this work, a model reference adaptive control-based estimated algorithm is proposed for online multi-parameter identification of surface-mounted permanent magnet synchronous machines. By taking the dq-axis equations of a practical motor as the reference model and the dq-axis estimation equations as the adjustable model, a standard model-reference-adaptive-system-based estimator was established. Additionally, the Popov hyperstability principle was used in the design of the adaptive law to guarantee accurate convergence. In order to reduce the oscillation of identification result, this work introduces a first-order low-pass digital filter to improve precision regarding the parameter estimation. The proposed scheme was then applied to an SPM synchronous motor control system without any additional circuits and implemented using a DSP TMS320LF2812. For analysis, the experimental results reveal the effectiveness of the proposed method.

Control of non-conventional synchronous motors

CERN Document Server

Louis, Jean-Paul

2013-01-01

Classical synchronous motors are the most effective device to drive industrial production systems and robots with precision and rapidity. However, numerous applications require efficient controls in non-conventional situations. Firstly, this is the case with synchronous motors supplied by thyristor line-commutated inverters, or with synchronous motors with faults on one or several phases. Secondly, many drive systems use non-conventional motors such as polyphase (more than three phases) synchronous motors, synchronous motors with double excitation, permanent magnet linear synchronous motors,

Anti-synchronization of chaotic oscillators

International Nuclear Information System (INIS)

Kim, Chil-Min; Rim, Sunghwan; Kye, Won-Ho; Ryu, Jung-Wan; Park, Young-Jai

2003-01-01

We have observed anti-synchronization phenomena in coupled identical chaotic oscillators. Anti-synchronization can be characterized by the vanishing of the sum of relevant variables. We have qualitatively analyzed its base mechanism by using the dynamics of the difference and the sum of the relevant variables in coupled chaotic oscillators. Near the threshold of the synchronization and anti-synchronization transition, we have obtained the novel characteristic relation

Timing organization of a real-time multicore processor

DEFF Research Database (Denmark)

Schoeberl, Martin; Sparsø, Jens

2017-01-01

Real-time systems need a time-predictable computing platform. Computation, communication, and access to shared resources needs to be time-predictable. We use time division multiplexing to statically schedule all computation and communication resources, such as access to main memory or message...... passing over a network-on-chip. We use time-driven communication over an asynchronous network-on-chip to enable time division multiplexing even in a globally asynchronous, locally synchronous multicore architecture. Using time division multiplexing at all levels of the architecture yields in a time...

Entity-based Classification of Twitter Messages

OpenAIRE

Yerva, Surender Reddy; Miklós, Zoltán; Aberer, Karl

2012-01-01

Twitter is a popular micro-blogging service on theWeb, where people can enter short messages, which then become visible to some other users of the service. While the topics of these messages varies, there are a lot of messages where the users express their opinions about some companies or their products. These messages are a rich source of information for companies for sentiment analysis or opinion mining. There is however a great obstacle for analyzing the messages directly: as the company n...

Fear, threat and efficacy in threat appeals: message involvement as a key mediator to message acceptance.

Science.gov (United States)

Cauberghe, Verolien; De Pelsmacker, Patrick; Janssens, Wim; Dens, Nathalie

2009-03-01

In a sample of 170 youngsters, the effect of two versions of a public service announcement (PSA) threat appeal against speeding, placed in four different contexts, on evoked fear, perceived threat (severity and probability of occurrence), perceived response efficacy and self-efficacy, message involvement and anti-speeding attitude and anti-speeding intention is investigated. Evoked fear and perceived threat and efficacy independently influence message involvement. Message involvement is a full mediator between evoked fear, perceived threat and efficacy perception on the one hand, and attitudes towards the message and behavioral intention to accept the message on the other. Speeding experience has a significantly negative impact on anti-speeding attitudes. Message and medium context threat levels and context thematic congruency have a significant effect on evoked fear and to a lesser extent on perceived threat.

Getting the message across: age differences in the positive and negative framing of health care messages.

Science.gov (United States)

Shamaskin, Andrea M; Mikels, Joseph A; Reed, Andrew E

2010-09-01

Although valenced health care messages influence impressions, memory, and behavior (Levin, Schneider, & Gaeth, 1998) and the processing of valenced information changes with age (Carstensen & Mikels, 2005), these 2 lines of research have thus far been disconnected. This study examined impressions of, and memory for, positively and negatively framed health care messages that were presented in pamphlets to 25 older adults and 24 younger adults. Older adults relative to younger adults rated positive pamphlets more informative than negative pamphlets and remembered a higher proportion of positive to negative messages. However, older adults misremembered negative messages to be positive. These findings demonstrate the age-related positivity effect in health care messages with promise as to the persuasive nature and lingering effects of positive messages. (c) 2010 APA, all rights reserved.

Manipulative Use of Short Messaging Service (SMS Text Messages by Nigerian Telecommunications Companies

Directory of Open Access Journals (Sweden)

Ayoola, Kehinde A.

2014-02-01

Full Text Available This paper is an application of Relevance Theory for the interpretation of short messaging service (SMS text messages emanating from Nigerian telecommunications companies to their subscribers. The aim of the research was to identify and describe the manipulative strategies employed by Nigerian telecommunications companies to induce subscribers to part with their money through sales promotion lotteries. 100 SMS texts were purposively extracted from the cell phones of randomly selected residents of Lagos Nigeria who had received promotional SMS text messages from three major Nigerian telecommunications companies. Using Sperber and Wilson's Relevance Theory (1995 as its theoretical framework, the paper described the manipulative use of SMS by Nigerian telecommunications companies. The analysis revealed that SMS text messages were encoded to achieve maximization of relevance through explicature and implicature; contextual implication and strengthening; and the reduction of processing effort through violating the maxim of truthfulness and the creative use of graphology. The paper concludes that SMS text-messages were used manipulatively by Nigerian telecommunications companies to earn indirect income from sales promotion lottery.

Multi-pass spectroscopic ellipsometry

International Nuclear Information System (INIS)

Stehle, Jean-Louis; Samartzis, Peter C.; Stamataki, Katerina; Piel, Jean-Philippe; Katsoprinakis, George E.; Papadakis, Vassilis; Schimowski, Xavier; Rakitzis, T. Peter; Loppinet, Benoit

2014-01-01

Spectroscopic ellipsometry is an established technique, particularly useful for thickness measurements of thin films. It measures polarization rotation after a single reflection of a beam of light on the measured substrate at a given incidence angle. In this paper, we report the development of multi-pass spectroscopic ellipsometry where the light beam reflects multiple times on the sample. We have investigated both theoretically and experimentally the effect of sample reflectivity, number of reflections (passes), angles of incidence and detector dynamic range on ellipsometric observables tanΨ and cosΔ. The multiple pass approach provides increased sensitivity to small changes in Ψ and Δ, opening the way for single measurement determination of optical thickness T, refractive index n and absorption coefficient k of thin films, a significant improvement over the existing techniques. Based on our results, we discuss the strengths, the weaknesses and possible applications of this technique. - Highlights: • We present multi-pass spectroscopic ellipsometry (MPSE), a multi-pass approach to ellipsometry. • Different detectors, samples, angles of incidence and number of passes were tested. • N passes improve polarization ratio sensitivity to the power of N. • N reflections improve phase shift sensitivity by a factor of N. • MPSE can significantly improve thickness measurements in thin films

Coexistence and switching of anticipating synchronization and lag synchronization in an optical system

International Nuclear Information System (INIS)

Wu, Liang; Zhu, Shiqun

2003-01-01

The chaotic synchronization between two bi-directionally coupled external cavity single-mode semiconductor lasers is investigated. Numerical simulation shows that anticipating synchronization and lag synchronization coexist and switch between each other in certain parameter regime. The anticipating time with different effects that were discussed quite differently in the previous theoretical analysis and experimental observation is determined by the involved parameters in the system

Adaptive Backoff Synchronization Techniques

Science.gov (United States)

1989-07-01

Percentage of synchronization and non- synchronisation references that cause invalidations in directory schemes with 2, 3, 4, 5, and 64 pointers...processors to arrive. The slight relative increase of synchronisation overhead in all cases when going from two to five pointers is because synchronization ...MASSACHUSETTS INSTITUTE OF TECHNOLOGY VLSI PUBLICATIONS q~JU VLSI Memo No. 89-547 It July 1989 Adaptive Backoff Synchronization Techniques Anant

Synchronicity and Leadership

NARCIS (Netherlands)

Merry, Philip

2017-01-01

LAY SUMMARY SYNCHRONICITY AND LEADERSHIP TILBURG PHD DISSERTATION, PHILIP MERRY World’s First PhD to Research Synchronicity And Leadership Using Grounded Theory OUT OF THE BLUE COINCIDENCES: research topic Most people have had the experience of thinking of someone and then, almost magically have

Synchronous implementation of optoelectronic NOR and XNOR logic gates using parallel synchronization of three chaotic lasers

International Nuclear Information System (INIS)

Yan Sen-Lin

2014-01-01

The parallel synchronization of three chaotic lasers is used to emulate optoelectronic logic NOR and XNOR gates via modulating the light and the current. We deduce a logical computational equation that governs the chaotic synchronization, logical input, and logical output. We construct fundamental gates based on the three chaotic lasers and define the computational principle depending on the parallel synchronization. The logic gate can be implemented by appropriately synchronizing two chaotic lasers. The system shows practicability and flexibility because it can emulate synchronously an XNOR gate, two NOR gates, and so on. The synchronization can still be deteceted when mismatches exist with a certain range. (general)

Improving the effectiveness of fundraising messages: The impact of charity goal attainment, message framing, and evidence on persuasion

NARCIS (Netherlands)

Das, E.; Kerkhof, P.; Kuiper, J.

2008-01-01

This experimental study assessed the effectiveness of fundraising messages. Based on recent findings regarding the effects of message framing and evidence, effective fundraising messages should combine abstract, statistical information with a negative message frame and anecdotal evidence with a

The impact of cultural exposure and message framing on oral health behavior: Exploring the role of message memory

Science.gov (United States)

Brick, Cameron; McCully, Scout N.; Updegraff, John A.; Ehret, Phillip J.; Areguin, Maira A.; Sherman, David K.

2015-01-01

Background Health messages are more effective when framed to be congruent with recipient characteristics, and health practitioners can strategically decide on message features to promote adherence to recommended behaviors. We present exposure to United States (U.S.) culture as a moderator of the impact of gain- vs. loss-frame messages. Since U.S. culture emphasizes individualism and approach orientation, greater cultural exposure was expected to predict improved patient choices and memory for gain-framed messages, whereas individuals with less exposure to U.S. culture would show these advantages for loss-framed messages. Methods 223 participants viewed a written oral health message in one of three randomized conditions: gain-frame, loss-frame, or no-message control, and were given ten flosses. Cultural exposure was measured with the proportions of life spent and parents born in the U.S. At baseline and one week later, participants completed recall tests and reported recent flossing behavior. Results Message frame and cultural exposure interacted to predict improved patient decisions (increased flossing) and memory maintenance for the health message over one week. E.g., those with low cultural exposure who saw a loss-frame message flossed more. Incongruent messages led to the same flossing rates as no message. Memory retention did not explain the effect of message congruency on flossing. Limitations Flossing behavior was self-reported. Cultural exposure may only have practical application in either highly individualistic or collectivistic countries. Conclusions In healthcare settings where patients are urged to follow a behavior, asking basic demographic questions could allow medical practitioners to intentionally communicate in terms of gains or losses to improve patient decision making and treatment adherence. PMID:25654986

Instructor's guide : - synchronized skating school

OpenAIRE

Mokkila, Eveliina

2011-01-01

The starting point to the Instructor’s guide for synchronized skating school was the situation that Turun Riennon Taitoluistelu figure skating club constantly struggles to get enough skaters to the Beginner team in synchronized skating. The guidebook was written to guide the skating school instructors towards providing more synchronized skating teaching in their lessons. As a result from introducing synchronized skating more in the skating school, it is expected to have more children conti...

Developing effective messages about potable recycled water: The importance of message structure and content

Science.gov (United States)

Price, J.; Fielding, K. S.; Gardner, J.; Leviston, Z.; Green, M.

2015-04-01

Community opposition is a barrier to potable recycled water schemes. Effective communication strategies about such schemes are needed. Drawing on social psychological literature, two experimental studies are presented, which explore messages that improve public perceptions of potable recycled water. The Elaboration-Likelihood Model of information processing and attitude change is tested and supported. Study 1 (N = 415) premeasured support for recycled water, and trust in government information at Time 1. Messages varied in complexity and sidedness were presented at Time 2 (3 weeks later), and support and trust were remeasured. Support increased after receiving information, provided that participants received complex rather than simple information. Trust in government was also higher after receiving information. There was tentative evidence of this in response to two-sided messages rather than one-sided messages. Initial attitudes to recycled water moderated responses to information. Those initially neutral or ambivalent responded differently to simple and one-sided messages, compared to participants with positive or negative attitudes. Study 2 (N = 957) tested the effectiveness of information about the low relative risks, and/or benefits of potable recycled water, compared to control groups. Messages about the low risks resulted in higher support when the issue of recycled water was relevant. Messages about benefits resulted in higher perceived issue relevance, but did not translate into greater support. The results highlight the importance of understanding people's motivation to process information, and need to tailor communication to match attitudes and stage of recycled water schemes' development.

Symbol synchronization and sampling frequency synchronization techniques in real-time DDO-OFDM systems

Science.gov (United States)

Chen, Ming; He, Jing; Cao, Zizheng; Tang, Jin; Chen, Lin; Wu, Xian

2014-09-01

In this paper, we propose and experimentally demonstrate a symbol synchronization and sampling frequency synchronization techniques in real-time direct-detection optical orthogonal frequency division multiplexing (DDO-OFDM) system, over 100-km standard single mode fiber (SSMF) using a cost-effective directly modulated distributed feedback (DFB) laser. The experiment results show that the proposed symbol synchronization based on training sequence (TS) has a low complexity and high accuracy even at a sampling frequency offset (SFO) of 5000-ppm. Meanwhile, the proposed pilot-assisted sampling frequency synchronization between digital-to-analog converter (DAC) and analog-to-digital converter (ADC) is capable of estimating SFOs with an accuracy of technique can also compensate SFO effects within a small residual SFO caused by deviation of SFO estimation and low-precision or unstable clock source. The two synchronization techniques are suitable for high-speed DDO-OFDM transmission systems.

Toward Predicting Popularity of Social Marketing Messages

Science.gov (United States)

Yu, Bei; Chen, Miao; Kwok, Linchi

Popularity of social marketing messages indicates the effectiveness of the corresponding marketing strategies. This research aims to discover the characteristics of social marketing messages that contribute to different level of popularity. Using messages posted by a sample of restaurants on Facebook as a case study, we measured the message popularity by the number of "likes" voted by fans, and examined the relationship between the message popularity and two properties of the messages: (1) content, and (2) media type. Combining a number of text mining and statistics methods, we have discovered some interesting patterns correlated to "more popular" and "less popular" social marketing messages. This work lays foundation for building computational models to predict the popularity of social marketing messages in the future.

Synchronization of Concurrent Processes

Science.gov (United States)

1975-07-01

Pettersen Stanford Ur.iversity Artificial Intelligence Laboratory ABSTRACT Th oaoer gives an overview of commonly used synchronization primitives and...wr.ters . ut.l.z.ng the DroDo4d synchronization primitive . The solution is simpler and shorter than other known S’ms The first sections of the paper...un reicr»» side il nrcttaary and Identity by block number) Scheduling, process scheduling, synchronization , mutual exclusion, semaphores , critical

A Messaging Infrastructure for WLCG

International Nuclear Information System (INIS)

Casey, James; Cons, Lionel; Lapka, Wojciech; Paladin, Massimo; Skaburskas, Konstantin

2011-01-01

During the EGEE-III project operational tools such as SAM, Nagios, Gridview, the regional Dashboard and GGUS moved to a communication architecture based on ActiveMQ, an open-source enterprise messaging solution. LHC experiments, in particular ATLAS, developed prototypes of systems using the same messaging infrastructure, validating the system for their use-cases. In this paper we describe the WLCG messaging use cases and outline an improved messaging architecture based on the experience gained during the EGEE-III period. We show how this provides a solid basis for many applications, including the grid middleware, to improve their resilience and reliability.

Cross-spectrum symbol synchronization

Science.gov (United States)

Mccallister, R. D.; Simon, M. K.

1981-01-01

A popular method of symbol synchronization exploits one aspect of generalized harmonic analysis, normally referred to as the cross-spectrum. Utilizing nonlinear techniques, the input symbol energy is effectively concentrated onto multiples of the symbol clock frequency, facilitating application of conventional phase lock synchronization techniques. A general treatment of the cross-spectrum technique is developed and shown to be applicable across a broad class of symbol modulation formats. An important specific symbol synchronization application is then treated, focusing the general development to provide both insight and quantitative measure of the performance impact associated with variation in these key synchronization parameters: symbol modulation format, symbol transition probability, symbol energy to noise density ratio, and symbol rate to filter bandwidth ratio.

Unidirectional synchronization of Hodgkin-Huxley neurons

Energy Technology Data Exchange (ETDEWEB)

Cornejo-Perez, Octavio [Division de Matematicas Aplicadas y Sistemas, Computacionales, IPICYT, Apdo. Postal 3-74 Tangamanga, 78231 San Luis Potosi (Mexico)]. E-mail: octavio@ipicyt.edu.mx; Femat, Ricardo [Division de Matematicas Aplicadas y Sistemas, Computacionales, IPICYT, Apdo. Postal 3-74 Tangamanga, 78231 San Luis Potosi (Mexico)]. E-mail: rfemat@ipicyt.edu.mx

2005-07-01

Synchronization dynamics of two noiseless Hodgkin-Huxley (HH) neurons under the action of feedback control is studied. The spiking patterns of the action potentials evoked by periodic external modulations attain synchronization states under the feedback action. Numerical simulations for the synchronization dynamics of regular-irregular desynchronized spiking sequences are displayed. The results are discussed in context of generalized synchronization. It is also shown that the HH neurons can be synchronized in face of unmeasured states.

Hybrid synchronization of hyperchaotic Lu system

Indian Academy of Sciences (India)

In this paper, we study the hybrid synchronization between two identical hyperchaotic Lu systems. Hybrid synchronization of hyperchaotic Lu system is achieved through synchronization of two pairs of states and anti-synchronization of the other two pairs of states. Active controls are designed to achieve hybrid ...

Distributed parallel messaging for multiprocessor systems

Science.gov (United States)

Chen, Dong; Heidelberger, Philip; Salapura, Valentina; Senger, Robert M; Steinmacher-Burrow, Burhard; Sugawara, Yutaka

2013-06-04

A method and apparatus for distributed parallel messaging in a parallel computing system. The apparatus includes, at each node of a multiprocessor network, multiple injection messaging engine units and reception messaging engine units, each implementing a DMA engine and each supporting both multiple packet injection into and multiple reception from a network, in parallel. The reception side of the messaging unit (MU) includes a switch interface enabling writing of data of a packet received from the network to the memory system. The transmission side of the messaging unit, includes switch interface for reading from the memory system when injecting packets into the network.

When communications collide with recipients' actions: effects of post-message behavior on intentions to follow the message recommendation.

Science.gov (United States)

Albarracín, Dolores; Cohen, Joel B; Kumkale, G Tarcan

2003-07-01

Two experiments investigated the processes through which post-message behavior (e.g., noncompliance) influences resistance to the message. Participants in Experiment 1 read preventive, consumer-education messages that either opposed the consumption of an alcohol-like product or recommended moderation. Half of the participants then tried the product, whereas the remaining participants performed a filler task. In the absence of trial, the two messages had the same effect. However, recipients of the abstinence-promoting preventive message who tried the product had stronger intentions to use the product in the future than recipients of the moderation message. This finding suggests that assessments of message impact may be inadequate unless an opportunity for trial is also provided. Results are interpreted in terms of self-perception and cognitive dissonance and contrasted from psychological reactance.

When Communications Collide With Recipients’ Actions: Effects of Post-Message Behavior on Intentions to Follow the Message Recommendation

Science.gov (United States)

Albarracín, Dolores; Cohen, Joel B.; Kumkale, G. Tarcan

2013-01-01

Two experiments investigated the processes through which post-message behavior (e.g., noncompliance) influences resistance to the message. Participants in Experiment 1 read preventive, consumer-education messages that either opposed the consumption of an alcohol-like product or recommended moderation. Half of the participants then tried the product, whereas the remaining participants performed a filler task. In the absence of trial, the two messages had the same effect. However, recipients of the abstinence-promoting preventive message who tried the product had stronger intentions to use the product in the future than recipients of the moderation message. This finding suggests that assessments of message impact may be inadequate unless an opportunity for trial is also provided. Results are interpreted in terms of self-perception and cognitive dissonance and contrasted from psychological reactance. PMID:15018672

A Mobile GPS Application: Mosque Tracking with Prayer Time Synchronization

Science.gov (United States)

Hashim, Rathiah; Ikhmatiar, Mohammad Sibghotulloh; Surip, Miswan; Karmin, Masiri; Herawan, Tutut

Global Positioning System (GPS) is a popular technology applied in many areas and embedded in many devices, facilitating end-users to navigate effectively to user's intended destination via the best calculated route. The ability of GPS to track precisely according to coordinates of specific locations can be utilized to assist a Muslim traveler visiting or passing an unfamiliar place to find the nearest mosque in order to perform his prayer. However, not many techniques have been proposed for Mosque tracking. This paper presents the development of GPS technology in tracking the nearest mosque using mobile application software embedded with the prayer time's synchronization system on a mobile application. The prototype GPS system developed has been successfully incorporated with a map and several mosque locations.

Synchronous adenocarcinomas of the colon presenting as synchronous colocolic intussusceptions in an adult

Directory of Open Access Journals (Sweden)

Chen Chuang-Wei

2012-12-01

Full Text Available Abstract Intussusception is uncommon in adults. To our knowledge, synchronous colocolic intussusceptions have never been reported in the literature. Here we described the case of a 59-year-old female of synchronous colocolic intussusceptions presenting as acute abdomen that was diagnosed by CT preoperatively. Laparotomy with radical right hemicolectomy and sigmoidectomy was undertaken without reduction of the invagination due to a significant risk of associated malignancy. The final diagnosis was synchronous adenocarcinoma of proximal transverse colon and sigmoid colon without lymph nodes or distant metastasis. The patient had an uneventful recovery. The case also emphasizes the importance of thorough exploration during surgery for bowel invagination since synchronous events may occur.

System of message for gamma-radiation monitor

International Nuclear Information System (INIS)

Bolic, M.D.; Koturovic, A.M.

2001-01-01

Paper describes a system of voice messages for gamma-radiation monitor based on PC. The systems reproduces recorded messages that is simpler than the process of their synthesis. Message choice is based on combination of recorded digital results and/or received reference messages or warnings. The system of generation of voice messages applies the Windows based software. The total memory array required to create independent voice system is maximum 1.7 mbyte. The monitor may be used for continuous monitoring of radioactivity level with 5-8 s period of message repetition. Another option of the system operation is based on monitor application for the environment monitoring. Period of messages in this case is equal to 5-30 min [ru

Guidelines for designing messages in risk communication

International Nuclear Information System (INIS)

Takashita, Hirofumi; Horikoshi, Hidehiko

2004-07-01

Risk Communication Study Team (hereafter called RC team) has designed messages for risk communication based on the analysis of the local residents' opinions which were expressed in several questionnaire surveys. The messages are described in a side format (Power Point format) every single content. This report provides basic guidelines for making messages that are used for risk communication, and does not include concrete messages which RC team designed. The RC team has already published the report entitled 'Information materials for risk communication' (JNC TN8450 2003-008) separately, and it gives the concrete messages. This report shows general cautions and checklists in designing messages, comments on the messages from outside risk communication experts, and opinions from local residents. (author)

Evaluation of Sexual Communication Message Strategies

Science.gov (United States)

2011-01-01

Parent-child communication about sex is an important proximal reproductive health outcome. But while campaigns to promote it such as the Parents Speak Up National Campaign (PSUNC) have been effective, little is known about how messages influence parental cognitions and behavior. This study examines which message features explain responses to sexual communication messages. We content analyzed 4 PSUNC ads to identify specific, measurable message and advertising execution features. We then develop quantitative measures of those features, including message strategies, marketing strategies, and voice and other stylistic features, and merged the resulting data into a dataset drawn from a national media tracking survey of the campaign. Finally, we conducted multivariable logistic regression models to identify relationships between message content and ad reactions/receptivity, and between ad reactions/receptivity and parents' cognitions related to sexual communication included in the campaign's conceptual model. We found that overall parents were highly receptive to the PSUNC ads. We did not find significant associations between message content and ad reactions/receptivity. However, we found that reactions/receptivity to specific PSUNC ads were associated with increased norms, self-efficacy, short- and long-term expectations about parent-child sexual communication, as theorized in the conceptual model. This study extends previous research and methods to analyze message content and reactions/receptivity. The results confirm and extend previous PSUNC campaign evaluation and provide further evidence for the conceptual model. Future research should examine additional message content features and the effects of reactions/receptivity. PMID:21599875

Evaluation of Sexual Communication Message Strategies

Directory of Open Access Journals (Sweden)

Khan Munziba

2011-05-01

Full Text Available Abstract Parent-child communication about sex is an important proximal reproductive health outcome. But while campaigns to promote it such as the Parents Speak Up National Campaign (PSUNC have been effective, little is known about how messages influence parental cognitions and behavior. This study examines which message features explain responses to sexual communication messages. We content analyzed 4 PSUNC ads to identify specific, measurable message and advertising execution features. We then develop quantitative measures of those features, including message strategies, marketing strategies, and voice and other stylistic features, and merged the resulting data into a dataset drawn from a national media tracking survey of the campaign. Finally, we conducted multivariable logistic regression models to identify relationships between message content and ad reactions/receptivity, and between ad reactions/receptivity and parents' cognitions related to sexual communication included in the campaign's conceptual model. We found that overall parents were highly receptive to the PSUNC ads. We did not find significant associations between message content and ad reactions/receptivity. However, we found that reactions/receptivity to specific PSUNC ads were associated with increased norms, self-efficacy, short- and long-term expectations about parent-child sexual communication, as theorized in the conceptual model. This study extends previous research and methods to analyze message content and reactions/receptivity. The results confirm and extend previous PSUNC campaign evaluation and provide further evidence for the conceptual model. Future research should examine additional message content features and the effects of reactions/receptivity.

TXT@WORK: pediatric hospitalists and text messaging.

Science.gov (United States)

Kuhlmann, Stephanie; Ahlers-Schmidt, Carolyn R; Steinberger, Erik

2014-07-01

Many studies assess provider-patient communication through text messaging; however, minimal research has addressed communication among physicians. The purpose of this study was to evaluate the use of text messaging by pediatric hospitalists. A brief, anonymous, electronic survey was distributed through the American Academy of Pediatrics Section on Hospital Medicine Listserv in February 2012. Survey questions assessed work-related text messaging. Of the 106 pediatric hospitalist respondents, 97 met inclusion criteria. Most were female (73%) and had been in practice text messages, some (12%) more than 10 times per shift. More than half (53%) received work-related text messages when not at work. When asked to identify all potential work recipients, most often sent work-related text messages to other pediatric hospitalists (64%), fellows or resident physicians (37%), and subspecialists/consulting physicians (28%). When asked their preferred mode for brief communication, respondents' preferences varied. Many (46%) respondents worried privacy laws can be violated by sending/receiving text messages, and some (30%) reported having received protected health information (PHI) through text messages. However, only 11% reported their institution offered encryption software for text messaging. Physicians were using text messaging as a means of brief, work-related communication. Concerns arose regarding transfer of PHI using unsecure systems and work-life balance. Future research should examine accuracy and effectiveness of text message communication in the hospital, as well as patient privacy issues.

Medical issues in synchronized skating.

Science.gov (United States)

Abbott, Kristin; Hecht, Suzanne

2013-01-01

Synchronized skating is a unique sport of team skating and currently represents the largest competitive discipline in U.S. Figure Skating. Synchronized skating allows skaters to compete as part of a team with opportunities to represent their country in international competitions. As the popularity of the sport continues to grow, more of these athletes will present to sports medicine clinics with injuries and illnesses related to participation in synchronized skating. The purpose of this article is to review the common injuries and medical conditions affecting synchronized skaters.

Ultrastructural evaluation of multiple pass low energy versus single pass high energy radio-frequency treatment.

Science.gov (United States)

Kist, David; Burns, A Jay; Sanner, Roth; Counters, Jeff; Zelickson, Brian

2006-02-01

The radio-frequency (RF) device is a system capable of volumetric heating of the mid to deep dermis and selective heating of the fibrous septa strands and fascia layer. Clinically, these effects promote dermal collagen production, and tightening of these deep subcutaneous structures. A new technique of using multiple low energy passes has been described which results in lower patient discomfort and fewer side effects. This technique has also been anecdotally described as giving more reproducible and reliable clinical results of tissue tightening and contouring. This study will compare ultrastructural changes in collagen between a single pass high energy versus up to five passes of a multiple pass lower energy treatment. Three subjects were consented and treated in the preauricular region with the RF device using single or multiple passes (three or five) in the same 1.5 cm(2) treatment area with a slight delay between passes to allow tissue cooling. Biopsies from each treatment region and a control biopsy were taken immediately, 24 hours or 6 months post treatment for electron microscopic examination of the 0-1 mm and 1-2 mm levels. Sections of tissue 1 mm x 1 mm x 80 nm were examined with an RCA EMU-4 Transmission Electron Microscope. Twenty sections from 6 blocks from each 1 mm depth were examined by 2 blinded observers. The morphology and degree of collagen change in relation to area examined was compared to the control tissue, and estimated using a quantitative scale. Ultrastructural examination of tissue showed that an increased amount of collagen fibril changes with increasing passes at energies of 97 J (three passes) and 122 J (five passes), respectively. The changes seen after five multiple passes were similar to those detected after much more painful single pass high-energy treatments. This ultrastructural study shows changes in collagen fibril morphology with an increased effect demonstrated at greater depths of the skin with multiple low-fluence passes

78 FR 52166 - Quantitative Messaging Research

Science.gov (United States)

2013-08-22

... COMMODITY FUTURES TRADING COMMISSION Quantitative Messaging Research AGENCY: Commodity Futures... survey will follow qualitative message testing research (for which CFTC received fast-track OMB approval... message testing research (for which CFTC received fast-track OMB approval) and is necessary to identify...

STUDYING BUSINESS CYCLES SYNCHRONIZATION

Directory of Open Access Journals (Sweden)

N. Servetnyk

2014-06-01

Full Text Available The paper researches business cycles synchronization. The fluctuations in post-Soviet countries are considered. The study examines different measures of synchronization in groups of countries according to some criteria.

Source Similarity and Social Media Health Messages: Extending Construal Level Theory to Message Sources.

Science.gov (United States)

Young, Rachel

2015-09-01

Social media users post messages about health goals and behaviors to online social networks. Compared with more traditional sources of health communication such as physicians or health journalists, peer sources are likely to be perceived as more socially close or similar, which influences how messages are processed. This experimental study uses construal level theory of psychological distance to predict how mediated health messages from peers influence health-related cognition and behavioral intention. Participants were exposed to source cues that identified peer sources as being either highly attitudinally and demographically similar to or different from participants. As predicted by construal level theory, participants who perceived sources of social media health messages as highly similar listed a greater proportion of beliefs about the feasibility of health behaviors and a greater proportion of negative beliefs, while participants who perceived sources as more dissimilar listed a greater proportion of positive beliefs about the health behaviors. Results of the study could be useful in determining how health messages from peers could encourage individuals to set realistic health goals.

TPG bus passes

CERN Multimedia

Staff Association

2013-01-01

The CERN Staff Association will stop selling TPG bus passes. All active and retired members of the CERN personnel will be able to purchase Unireso bus passes from the CERN Hostel - Building 39 (Meyrin site) from 1st February 2013. For more information: https://cds.cern.ch/journal/CERNBulletin/2013/04/Announcements/1505279?ln=en

Effects of Text Messaging on Academic Performance

Directory of Open Access Journals (Sweden)

Barks Amanda

2011-12-01

Full Text Available University students frequently send and receive cellular phone text messages during classroominstruction. Cognitive psychology research indicates that multi-tasking is frequently associatedwith performance cost. However, university students often have considerable experience withelectronic multi-tasking and may believe that they can devote necessary attention to a classroomlecture while sending and receiving text messages. In the current study, university students whoused text messaging were randomly assigned to one of two conditions: 1. a group that sent andreceived text messages during a lecture or, 2. a group that did not engage in text messagingduring the lecture. Participants who engaged in text messaging demonstrated significantlypoorer performance on a test covering lecture content compared with the group that did notsend and receive text messages. Participants exhibiting higher levels of text messaging skill hadsignificantly lower test scores than participants who were less proficient at text messaging. It ishypothesized that in terms of retention of lecture material, more frequent task shifting by thosewith greater text messaging proficiency contributed to poorer performance. Overall, the findingsdo not support the view, held by many university students, that this form of multitasking has littleeffect on the acquisition of lecture content. Results provide empirical support for teachers andprofessors who ban text messaging in the classroom.

Clock synchronization and dispersion

International Nuclear Information System (INIS)

Giovannetti, Vittorio; Lloyd, Seth; Maccone, Lorenzo; Wong, Franco N C

2002-01-01

We present a method to defeat effects of dispersion of timing signals when synchronizing clocks. It is based on the recently proposed 'conveyor belt synchronization' scheme and on the quantum dispersion cancellation effect

Improving Type Error Messages in OCaml

OpenAIRE

Charguéraud , Arthur

2015-01-01

International audience; Cryptic type error messages are a major obstacle to learning OCaml or other ML-based languages. In many cases, error messages cannot be interpreted without a sufficiently-precise model of the type inference algorithm. The problem of improving type error messages in ML has received quite a bit of attention over the past two decades, and many different strategies have been considered. The challenge is not only to produce error messages that are both sufficiently concise ...

CMLOG: A common message logging system

International Nuclear Information System (INIS)

Chen, J.; Akers, W.; Bickley, M.; Wu, D.; Watson, W. III

1997-01-01

The Common Message Logging (CMLOG) system is an object-oriented and distributed system that not only allows applications and systems to log data (messages) of any type into a centralized database but also lets applications view incoming messages in real-time or retrieve stored data from the database according to selection rules. It consists of a concurrent Unix server that handles incoming logging or searching messages, a Motif browser that can view incoming messages in real-time or display stored data in the database, a client daemon that buffers and sends logging messages to the server, and libraries that can be used by applications to send data to or retrieve data from the database via the server. This paper presents the design and implementation of the CMLOG system meanwhile it will also address the issue of integration of CMLOG into existing control systems. CMLOG into existing control systems

Engineered cell-cell communication via DNA messaging

Directory of Open Access Journals (Sweden)

Ortiz Monica E

2012-09-01

Full Text Available Abstract Background Evolution has selected for organisms that benefit from genetically encoded cell-cell communication. Engineers have begun to repurpose elements of natural communication systems to realize programmed pattern formation and coordinate other population-level behaviors. However, existing engineered systems rely on system-specific small molecules to send molecular messages among cells. Thus, the information transmission capacity of current engineered biological communication systems is physically limited by specific biomolecules that are capable of sending only a single message, typically “regulate transcription.” Results We have engineered a cell-cell communication platform using bacteriophage M13 gene products to autonomously package and deliver heterologous DNA messages of varying lengths and encoded functions. We demonstrate the decoupling of messages from a common communication channel via the autonomous transmission of various arbitrary genetic messages. Further, we increase the range of engineered DNA messaging across semisolid media by linking message transmission or receipt to active cellular chemotaxis. Conclusions We demonstrate decoupling of a communication channel from message transmission within engineered biological systems via the autonomous targeted transduction of user-specified heterologous DNA messages. We also demonstrate that bacteriophage M13 particle production and message transduction occurs among chemotactic bacteria. We use chemotaxis to improve the range of DNA messaging, increasing both transmission distance and communication bit rates relative to existing small molecule-based communication systems. We postulate that integration of different engineered cell-cell communication platforms will allow for more complex spatial programming of dynamic cellular consortia.

Pinning Synchronization of Switched Complex Dynamical Networks

Directory of Open Access Journals (Sweden)

Liming Du

2015-01-01

Full Text Available Network topology and node dynamics play a key role in forming synchronization of complex networks. Unfortunately there is no effective synchronization criterion for pinning synchronization of complex dynamical networks with switching topology. In this paper, pinning synchronization of complex dynamical networks with switching topology is studied. Two basic problems are considered: one is pinning synchronization of switched complex networks under arbitrary switching; the other is pinning synchronization of switched complex networks by design of switching when synchronization cannot achieved by using any individual connection topology alone. For the two problems, common Lyapunov function method and single Lyapunov function method are used respectively, some global synchronization criteria are proposed and the designed switching law is given. Finally, simulation results verify the validity of the results.

Synchronization in complex networks

Energy Technology Data Exchange (ETDEWEB)

Arenas, A.; Diaz-Guilera, A.; Moreno, Y.; Zhou, C.; Kurths, J.

2007-12-12

Synchronization processes in populations of locally interacting elements are in the focus of intense research in physical, biological, chemical, technological and social systems. The many efforts devoted to understand synchronization phenomena in natural systems take now advantage of the recent theory of complex networks. In this review, we report the advances in the comprehension of synchronization phenomena when oscillating elements are constrained to interact in a complex network topology. We also overview the new emergent features coming out from the interplay between the structure and the function of the underlying pattern of connections. Extensive numerical work as well as analytical approaches to the problem are presented. Finally, we review several applications of synchronization in complex networks to different disciplines: biological systems and neuroscience, engineering and computer science, and economy and social sciences.

Chaos synchronization of coupled hyperchaotic system

International Nuclear Information System (INIS)

Yang Lixin; Chu Yandong; Zhang Jiangang; Li Xianfeng

2009-01-01

Chaos synchronization, as an important topic, has become an active research subject in nonlinear science. Over the past two decades, chaos synchronization between nonlinear systems has been extensively studied, and many types of synchronization have been announced. This paper introduces synchronization of coupled hyperchaotic system, based on the Lapunov stability theory, asymptotic stability of the system is guaranteed by means of Lapunov function. The numerical simulation was provided in order to show the effectiveness of this method for the synchronization of the chaotic hyperchaotic Chen system and Rossler system.

AIS reception from a CubeSat in LEO

DEFF Research Database (Denmark)

Larsen, Jesper Abildgaard; Mortensen, Hans Peter; Nielsen, Jens Frederik Dalsgaard

2013-01-01

The primary payloads on board the AAUSAT3 satellite are two different AIS receivers, one is a traditional hardware-based receiver, the other one is a software-defined radio receiver. The hardware-based receiver has been developed around an ADF-7020 transceiver, with an appropriate LNA in front...... into a low-Earth orbit with a semi-major axis of 7156 km, i.e. 800 km altitude, near circular, dusk-dawn Sun-synchronous orbit. From this orbit the AIS antenna system, which consists of a dipole antenna, has a foot print diameter of approximately 6000 km. During the first pass over the primary ground station...... at Aalborg University, basic telemetry and the first few AIS messages were downloaded. During the first 14 days of the mission, the two receivers managed to detect more than 100,000 different AIS messages from ships all around the world, and more than 35,000 of these messages have been successfully...

Hand hygiene posters: selling the message.

Science.gov (United States)

Jenner, E A; Jones, F; Fletcher, B C; Miller, L; Scott, G M

2005-02-01

This literature review was undertaken to determine the established theory and research that might be utilized to inform the construction of persuasive messages on hand hygiene posters. It discusses the principles of message framing and the use of fear appeals. Current theory suggests that the most effective messages for health promotion behaviours should be framed in terms of gains rather than losses for the individual. However, as clinical hand hygiene is largely for the benefit of others (i.e. patients), messages should also invoke a sense of personal responsibility and appeal to altruistic behaviour. The use of repeated minimal fear appeals have their place. Posters that simply convey training messages are not effective persuaders.

What's in a message? Delivering sexual health promotion to young people in Australia via text messaging

Directory of Open Access Journals (Sweden)

Hellard Margaret E

2010-12-01

Full Text Available Abstract Background Advances in communication technologies have dramatically changed how individuals access information and communicate. Recent studies have found that mobile phone text messages (SMS can be used successfully for short-term behaviour change. However there is no published information examining the acceptability, utility and efficacy of different characteristics of health promotion SMS. This paper presents the results of evaluation focus groups among participants who received twelve sexual health related SMS as part of a study examining the impact of text messaging for sexual health promotion to on young people in Victoria, Australia. Methods Eight gender-segregated focus groups were held with 21 males and 22 females in August 2008. Transcripts of audio recordings were analysed using thematic analysis. Data were coded under one or more themes. Results Text messages were viewed as an acceptable and 'personal' means of health promotion, with participants particularly valuing the informal language. There was a preference for messages that were positive, relevant and short and for messages to cover a variety of topics. Participants were more likely to remember and share messages that were funny, rhymed and/or tied into particular annual events. The message broadcasting, generally fortnightly on Friday afternoons, was viewed as appropriate. Participants said the messages provided new information, a reminder of existing information and reduced apprehension about testing for sexually transmitted infections. Conclusions Mobile phones, in particular SMS, offer health promoters an exciting opportunity to engage personally with a huge number of individuals for low cost. The key elements emerging from this evaluation, such as message style, language and broadcast schedule are directly relevant to future studies using SMS for health promotion, as well as for future health promotion interventions in other mediums that require short formats, such

The message development tool: a case for effective operationalization of messaging in social marketing practice.

Science.gov (United States)

Mattson, Marifran; Basu, Ambar

2010-07-01

That messages are essential, if not the most critical component of any communicative process, seems like an obvious claim. More so when the communication is about health--one of the most vital and elemental of human experiences (Babrow & Mattson, 2003). Any communication campaign that aims to change a target audience's health behaviors needs to centralize messages. Even though messaging strategies are an essential component of social marketing and are a widely used campaign model, health campaigns based on this framework have not always been able to effectively operationalize this key component, leading to cases where initiating and sustaining prescribed health behavior has been difficult (MacStravic, 2000). Based on an examination of the VERB campaign and an Australian breastfeeding promotion campaign, we propose a message development tool within the ambit of the social marketing framework that aims to extend the framework and ensure that the messaging component of the model is contextualized at the core of planning, implementation, and evaluation efforts.

Investigating the impact of viral message appeal and message credibility on consumer attitude toward brand

Directory of Open Access Journals (Sweden)

Majid Esmaeilpour

2016-12-01

Full Text Available Background - Due to the rapid growth of the Internet and use of e-commerce in recent years, viral marketing has drawn the attention of manufacturing and service organizations. However, no research has been conducted to examine the impact of message appeal and message source credibility on consumers' attitude with mediating role of intellectual involvement of consumers and their risk taking level. Purpose - The aim of this study was to examine the impact of appeal and message source credibility on consumers’ attitude with mediating role of consumers’ intellectual involvement and their risk taking level. Design/methodology/approach – The population of this study includes consumers of mobile phones (Samsung, Sony, Nokia, LG and iPhone in Bushehr city (Iran. As the population of the study is unlimited, 430 questionnaires were distributed using available sampling method, and 391 questionnaires were collected and analyzed. Using structural equation modeling, data were analyzed through smart PLS software. Findings –The results show that the appeal and credibility of the message source have impact on consumer attitudes toward the brand. It was also found that intellectual involvement of consumers plays the mediating role in the relationship between message appeal and consumer attitudes toward brand. In the relationship between message source credibility and customer attitude towards the brand, the level of risk taking of people has no mediating role. Research limitations/implications – Data collection tool was questionnaire in this study, and questionnaire has some disadvantages that can affect the results. Additionally, this study was conducted in Bushehr city (Iran. Therefore, we should be cautious in generalizing the findings. Originality/value – In this study, the effect of message appeal and message source credibility on consumer attitude to brand was examined. The risk taking level of consumer and his involvement level were considered

Bursting synchronization in clustered neuronal networks

International Nuclear Information System (INIS)

Yu Hai-Tao; Wang Jiang; Deng Bin; Wei Xi-Le

2013-01-01

Neuronal networks in the brain exhibit the modular (clustered) property, i.e., they are composed of certain subnetworks with differential internal and external connectivity. We investigate bursting synchronization in a clustered neuronal network. A transition to mutual-phase synchronization takes place on the bursting time scale of coupled neurons, while on the spiking time scale, they behave asynchronously. This synchronization transition can be induced by the variations of inter- and intracoupling strengths, as well as the probability of random links between different subnetworks. Considering that some pathological conditions are related with the synchronization of bursting neurons in the brain, we analyze the control of bursting synchronization by using a time-periodic external signal in the clustered neuronal network. Simulation results show a frequency locking tongue in the driving parameter plane, where bursting synchronization is maintained, even in the presence of external driving. Hence, effective synchronization suppression can be realized with the driving parameters outside the frequency locking region. (interdisciplinary physics and related areas of science and technology)

Message exchange in the building industry

NARCIS (Netherlands)

Vries, de B.; Somers, L.J.A.M.

1995-01-01

A process model is described for exchanging information in the building industry. In this model participants send and receive messages. On receipt of a message an activity is executed if all required information is available. Otherwise a message will be sent to another participant to obtain the

Diabetes education via mobile text messaging.

Science.gov (United States)

Wangberg, Silje C; Arsand, Eirik; Andersson, Niklas

2006-01-01

Living with diabetes makes great educational demands on a family. We have tested the feasibility of using the mobile phone short message service (SMS) for reaching people with diabetes information. We also assessed user satisfaction and perceived pros and cons of the medium through interviews. Eleven parents of children with type 1 diabetes received messages for 11 weeks. The parents were positive about the system and said that they would like to continue to use it. The pop-up reminding effect of SMS messages in busy everyday life was noted as positive. Some parents experienced the messages as somewhat intrusive, arriving too often and at inconvenient times. The parents also noted the potential of the messages to facilitate communication with their adolescent children. The inability to store all of the messages or to print them out were seen as major disadvantages. Overall, the SMS seems to hold promise as means of delivering diabetes information.

Recent computer attacks via Instant Messaging

CERN Multimedia

IT Department

2008-01-01

Be cautious of any unexpected messages containing web links even if they appear to come from known contacts. If you happen to click on such a link and if your permission is requested to run or install software, always decline it. Several computers at CERN have recently been broken into by attackers who have tricked users of Instant Messaging applications (e.g. MSN, Yahoo Messenger, etc.) into clicking on web links which appeared to come from known contacts. The links appeared to be photos from ‘friends’ and requested software to be installed. In practice, attacker software was installed and the messages did not come from real contacts. In the past such fake messages were mainly sent by email but now a wider range of applications are being targeted, including Instant Messaging. Cybercriminals are making growing use of fake messages to try to trick you into clicking on Web links which will help them to install malicious software on your computer. Anti-virus software cann...

Auctioning Bulk Mobile Messages

NARCIS (Netherlands)

S. Meij (Simon); L-F. Pau (Louis-François); H.W.G.M. van Heck (Eric)

2003-01-01

textabstractThe search for enablers of continued growth of SMS traffic, as well as the take-off of the more diversified MMS message contents, open up for enterprises the potential of bulk use of mobile messaging , instead of essentially one-by-one use. In parallel, such enterprises or value added

WebPASS Explorer (HR Personnel Management)

Data.gov (United States)

US Agency for International Development — WebPass Explorer (WebPASS Framework): USAID is partnering with DoS in the implementation of their WebPass Post Personnel (PS) Module. WebPassPS does not replace...

Synchronization controller design of two coupling permanent magnet synchronous motors system with nonlinear constraints.

Science.gov (United States)

Deng, Zhenhua; Shang, Jing; Nian, Xiaohong

2015-11-01

In this paper, two coupling permanent magnet synchronous motors system with nonlinear constraints is studied. First of all, the mathematical model of the system is established according to the engineering practices, in which the dynamic model of motor and the nonlinear coupling effect between two motors are considered. In order to keep the two motors synchronization, a synchronization controller based on load observer is designed via cross-coupling idea and interval matrix. Moreover, speed, position and current signals of two motor all are taken as self-feedback signal as well as cross-feedback signal in the proposed controller, which is conducive to improving the dynamical performance and the synchronization performance of the system. The proposed control strategy is verified by simulation via Matlab/Simulink program. The simulation results show that the proposed control method has a better control performance, especially synchronization performance, than that of the conventional PI controller. Copyright © 2015 ISA. Published by Elsevier Ltd. All rights reserved.

Neural Synchronization and Cryptography

Science.gov (United States)

Ruttor, Andreas

2007-11-01

Neural networks can synchronize by learning from each other. In the case of discrete weights full synchronization is achieved in a finite number of steps. Additional networks can be trained by using the inputs and outputs generated during this process as examples. Several learning rules for both tasks are presented and analyzed. In the case of Tree Parity Machines synchronization is much faster than learning. Scaling laws for the number of steps needed for full synchronization and successful learning are derived using analytical models. They indicate that the difference between both processes can be controlled by changing the synaptic depth. In the case of bidirectional interaction the synchronization time increases proportional to the square of this parameter, but it grows exponentially, if information is transmitted in one direction only. Because of this effect neural synchronization can be used to construct a cryptographic key-exchange protocol. Here the partners benefit from mutual interaction, so that a passive attacker is usually unable to learn the generated key in time. The success probabilities of different attack methods are determined by numerical simulations and scaling laws are derived from the data. They show that the partners can reach any desired level of security by just increasing the synaptic depth. Then the complexity of a successful attack grows exponentially, but there is only a polynomial increase of the effort needed to generate a key. Further improvements of security are possible by replacing the random inputs with queries generated by the partners.

Designing Skin Cancer Prevention Messages: Should We Emphasize Gains or Losses? Message Framing, Risk Type, and Prior Experience.

Science.gov (United States)

Lee, Moon J; Kang, Hannah

2018-05-01

To test whether message framing (ie, gain vs. loss) and risk type (ie, health vs appearance risk) in skin cancer prevention messages interact with one's prior experience. Two experiments with a 2 (message framing: gain vs loss) × 2 (risk type: health vs appearance risk) factorial design were conducted. The participants were given a URL to the experiment website via e-mail. On the first page of the website, the participants were told that they would be asked to evaluate a skin cancer print public service announcement (PSA): Online experiments. A total of 397 individuals participated (236 for experiment 1 and 161 for experiment 2). Apparatus: Four versions of the skin cancer print PSAs were developed. Four PSAs were identical except for the 2 manipulated components: message framing and risk type. Measures were adopted from Cho and Boster (message framing), Jones and Leary and Kiene et al. (risk type), De Vries, Mesters, van't Riet, Willems, and Reubsaet and Knight, Kirincich, Farmer, and Hood (prior experience), and Hammond, Fong, Zanna, Thrasher, and Borland and Hoffner and Ye (behavioral intent). General linear models were used to test hypotheses. Three-way interactions among message framing, risk type, and prior experience were found: When the intent of the message was to encourage sunscreen use, the effects of message framing and risk type were shown to be the exact opposite directions from when the intent was to discourage indoor/outdoor tanning. To discourage tanning among those with prior experience, messages emphasizing losses in terms of one's health will work better. For those with no prior experience, messages emphasizing potential appearance losses will work better for discouraging tanning while messages emphasizing gains like improving appearance will do a better job in encouraging sunscreen use.

Popular Mobilization Messaging

Directory of Open Access Journals (Sweden)

James Garrison

2017-04-01

Full Text Available This Research Paper examines the Iraqi Popular Mobilization Unit’s (PMU messaging on the organisation’s website and social media platforms through early January 2017 to develop a more nuanced understanding of the PMU’s outlook, both present and future. After providing an overview of the PMU’s media presence online, the paper discusses how the organisation promotes its core narrative: that it is a cross-confessional and patriotic force for the defence of all Iraqis against a brutal and evil IS. The paper then addresses the PMU’s use of messaging to refute the sectarian portrayal of the organisation in some quarters before turning to the way the PMU approaches regional and international states in its media. Finally, the paper summarises the PMU’s messaging strategy and discusses how this strategy implies a less threatening future for the organisation than is often anticipated.

Targeting engineering synchronization in chaotic systems

Science.gov (United States)

Bhowmick, Sourav K.; Ghosh, Dibakar

2016-07-01

A method of targeting engineering synchronization states in two identical and mismatch chaotic systems is explained in detail. The method is proposed using linear feedback controller coupling for engineering synchronization such as mixed synchronization, linear and nonlinear generalized synchronization and targeting fixed point. The general form of coupling design to target any desire synchronization state under unidirectional coupling with the help of Lyapunov function stability theory is derived analytically. A scaling factor is introduced in the coupling definition to smooth control without any loss of synchrony. Numerical results are done on two mismatch Lorenz systems and two identical Sprott oscillators.

Rf-synchronized imaging for particle and photon beam characterizations

Energy Technology Data Exchange (ETDEWEB)

Lumpkin, A.H.

1993-07-01

The usefulness of imaging electro-optics for rf-driven accelerators can be enhanced by synchronizing the instruments to the system fundamental frequency or an appropriate subharmonic. This step allows one to obtain micropulse bunch length and phase during a series of linac bunches or storage ring passes. Several examples now exist of the use of synchroscan and dual-sweep streak cameras and/or image dissector tubes to access micropulse scale phenomena (10 to 30 ps) during linac and storage ring operations in the US, Japan, and Europe. As space permits, selections will be presented from the list of phase stability phenomena on photoelectric injectors, micropulse length during a macropulse, micropulse elongation effects, transverse Wakefield effects within a micropulse, and submicropulse phenomena on a stored beam. Potential applications to the subsystems of the Advanced Photon Source (APS) will be briefly addressed.

Physical Layer Ethernet Clock Synchronization

Science.gov (United States)

2010-11-01

42 nd Annual Precise Time and Time Interval (PTTI) Meeting 77 PHYSICAL LAYER ETHERNET CLOCK SYNCHRONIZATION Reinhard Exel, Georg...oeaw.ac.at Nikolaus Kerö Oregano Systems, Mohsgasse 1, 1030 Wien, Austria E-mail: nikolaus.keroe@oregano.at Abstract Clock synchronization ...is a service widely used in distributed networks to coordinate data acquisition and actions. As the requirement to achieve tighter synchronization

Hooked on a feeling: Affective anti-smoking messages are more effective than cognitive messages at changing implicit evaluations of smoking

Directory of Open Access Journals (Sweden)

Colin Tucker Smith

2015-10-01

Full Text Available Because implicit evaluations are thought to underlie many aspects of behavior, researchers have started looking for ways to change them. We examine whether and when persuasive messages alter strongly-held implicit evaluations of smoking. In smokers, an affective anti-smoking message led to more negative implicit evaluations on four different implicit measures as compared to a cognitive anti-smoking message which seemed to backfire. Additional analyses suggested that the observed effects were mediated by the feelings and emotions raised by the messages. In non-smokers, both the affective and cognitive message engendered slightly more negative implicit evaluations. We conclude that persuasive messages change implicit evaluations in a way that depends on properties of the message and of the participant. Thus, our data open new avenues for research directed at tailoring persuasive messages to change implicit evaluations.

Hooked on a feeling: affective anti-smoking messages are more effective than cognitive messages at changing implicit evaluations of smoking.

Science.gov (United States)

Smith, Colin Tucker; De Houwer, Jan

2015-01-01

Because implicit evaluations are thought to underlie many aspects of behavior, researchers have started looking for ways to change them. We examine whether and when persuasive messages alter strongly held implicit evaluations of smoking. In smokers, an affective anti-smoking message led to more negative implicit evaluations on four different implicit measures as compared to a cognitive anti-smoking message which seemed to backfire. Additional analyses suggested that the observed effects were mediated by the feelings and emotions raised by the messages. In non-smokers, both the affective and cognitive message engendered slightly more negative implicit evaluations. We conclude that persuasive messages change implicit evaluations in a way that depends on properties of the message and of the participant. Thus, our data open new avenues for research directed at tailoring persuasive messages to change implicit evaluations.

Nonblocking and orphan free message logging protocols

Science.gov (United States)

Alvisi, Lorenzo; Hoppe, Bruce; Marzullo, Keith

1992-12-01

Currently existing message logging protocols demonstrate a classic pessimistic vs. optimistic tradeoff. We show that the optimistic-pessimistic tradeoff is not inherent to the problem of message logging. We construct a message-logging protocol that has the positive features of both optimistic and pessimistic protocol: our protocol prevents orphans and allows simple failure recovery; however, it requires no blocking in failure-free runs. Furthermore, this protocol does not introduce any additional message overhead as compared to one implemented for a system in which messages may be lost but processes do not crash.

"Which pass is better?" Novel approaches to assess passing effectiveness in elite soccer.

Science.gov (United States)

Rein, Robert; Raabe, Dominik; Memmert, Daniel

2017-10-01

Passing behaviour is a key property of successful performance in team sports. Previous investigations however have mainly focused on notational measurements like total passing frequencies which provide little information about what actually constitutes successful passing behaviour. Consequently, this has hampered the transfer of research findings into applied settings. Here we present two novel approaches to assess passing effectiveness in elite soccer by evaluating their effects on majority situations and space control in front of the goal. Majority situations are assessed by calculating the number of defenders between the ball carrier and the goal. Control of space is estimated using Voronoi-diagrams based on the player's positions on the pitch. Both methods were applied to position data from 103 German First division games from the 2011/2012, 2012/2013 and 2014/2015 seasons using a big data approach. The results show that both measures are significantly related to successful game play with respect to the number of goals scored and to the probability of winning a game. The results further show that on average passes from the mid-field into the attacking area are most effective. The presented passing efficiency measures thereby offer new opportunities for future applications in soccer and other sports disciplines whilst maintaining practical relevance with respect to tactical training regimes or game performances analysis. Copyright © 2017 Elsevier B.V. All rights reserved.

Nonlinear Dynamics of Controlled Synchronizations of Manipulator System

Directory of Open Access Journals (Sweden)

Qingkai Han

2014-01-01

Full Text Available The nonlinear dynamics of the manipulator system which is controlled to achieve the synchronization motions is investigated in the paper. Firstly, the control strategies and modeling approaches of the manipulator system are given, in which the synchronization goal is defined by both synchronization errors and its derivatives. The synchronization controllers applied on the manipulator system include neuron synchronization controller, improved OPCL synchronization controller, and MRAC-PD synchronization controller. Then, an improved adaptive synchronized control strategy is proposed in order to estimate online the unknown structure parameters and state variables of the manipulator system and to realize the needed synchronous compensation. Furthermore, a robust adaptive synchronization controller is also researched to guarantee the dynamic stability of the system. Finally, the stability of motion synchronizations of the manipulator system possessing nonlinear component is discussed, together with the effect of control parameters and joint friction and others. Some typical motions such as motion bifurcations and the loss of synchronization of it are obtained and illustrated as periodic, multiperiodic, and/or chaotic motion patterns.

The religious message in action - a case study

Directory of Open Access Journals (Sweden)

René Gothóni

1975-01-01

Full Text Available We understand a religious message to be the product of a religious movement. In studying such a message, it is very much to the purpose to place it in the context in which it operates. The cultural and social context of a religious message is some religious movement. Hence, the message should be examined against that framework. Each message has a certain structure, and its detection is of prime importance. Messages are not only part of the tradition, but themselves unique in their respective communicative situations. Thus, in our view, structural analysis does not have analytical use-value unless the message's symbols are set into their communicative context. The aim of this paper is dual: On the one hand, we intend to analyze and clarify the structure of a religious message of the Laestadian movement, how the message operates, also how the members of that movement respond to the codes of the message, and what kind of functions it fulfills; on the other, to develop and test an analytical model which would combine structural and interactional analysis.

Continuous and discontinuous transitions to synchronization.

Science.gov (United States)

Wang, Chaoqing; Garnier, Nicolas B

2016-11-01

We describe how the transition to synchronization in a system of globally coupled Stuart-Landau oscillators changes from continuous to discontinuous when the nature of the coupling is moved from diffusive to reactive. We explain this drastic qualitative change as resulting from the co-existence of a particular synchronized macrostate together with the trivial incoherent macrostate, in a range of parameter values for which the latter is linearly stable. In contrast to the paradigmatic Kuramoto model, this particular state observed at the synchronization transition contains a finite, non-vanishing number of synchronized oscillators, which results in a discontinuous transition. We consider successively two situations where either a fully synchronized state or a partially synchronized state exists at the transition. Thermodynamic limit and finite size effects are briefly discussed, as well as connections with recently observed discontinuous transitions.

Adaptive feedback synchronization of Lue system

International Nuclear Information System (INIS)

Han, X.; Lu, J.-A.; Wu, X.

2004-01-01

This letter further improves and extends the works of Chen and Lue [Chaos, Solitons and Fractals 14 (2002) 643] and Wang et al. [Phys. Lett. A 312 (2003) 34]. In detail, the linear feedback synchronization and adaptive feedback synchronization for Lue system are discussed. And the lower bound of the feedback gain in linear feedback synchronization is presented. The adaptive feedback synchronization with only one controller is designed, which improves the proof in the work by Wang et al. The adaptive synchronization with two controllers for completely uncertain Lue system is also discussed, which extends the work of Chen and Lue. Also, numerical simulations show the effectiveness of these methods

Message Scheduling and Forwarding in Congested DTNs

KAUST Repository

Elwhishi, Ahmed; Ho, Pin-Han; Shihada, Basem

2012-01-01

Multi-copy utility-based routing has been considered as one of the most applicable approaches to effective message delivery in Delay Tolerant Networks (DTNs). By allowing multiple message replicas launched, the ratio of message delivery or delay can be significantly reduced compared with other counterparts. Such an advantage, nonetheless, is at the expense of taking more buffer space at each node and higher complexity in message forwarding decisions. This paper investigates an efficient message scheduling and dropping policy via analytical modeling approach, aiming to achieve optimal performance in terms of message delivery delay. Extensive simulation results, based on a synthetic mobility model and real mobility traces, show that the proposed scheduling framework can achieve superb performance against its counterparts in terms of delivery delay.

Message Scheduling and Forwarding in Congested DTNs

KAUST Repository

Elwhishi, Ahmed

2012-08-19

Multi-copy utility-based routing has been considered as one of the most applicable approaches to effective message delivery in Delay Tolerant Networks (DTNs). By allowing multiple message replicas launched, the ratio of message delivery or delay can be significantly reduced compared with other counterparts. Such an advantage, nonetheless, is at the expense of taking more buffer space at each node and higher complexity in message forwarding decisions. This paper investigates an efficient message scheduling and dropping policy via analytical modeling approach, aiming to achieve optimal performance in terms of message delivery delay. Extensive simulation results, based on a synthetic mobility model and real mobility traces, show that the proposed scheduling framework can achieve superb performance against its counterparts in terms of delivery delay.

Does perceived risk influence the effects of message framing? Revisiting the link between prospect theory and message framing

NARCIS (Netherlands)

Riet, J.P. van 't; Cox, A.D.; Cox, D.; Zimet, G.D.; Bruijn, G.J. de; Putte, B. van den; Vries, H. de; Werrij, M.Q.; Ruiter, R.A.C.

2016-01-01

Health-promoting messages can be framed in terms of the beneficial consequences of healthy behaviour (gain-framed messages) or the detrimental consequences of unhealthy behaviour (loss-framed messages). An influential notion holds that the perceived risk associated with the recommended behaviour

Generalized synchronization between chimera states

Science.gov (United States)

Andrzejak, Ralph G.; Ruzzene, Giulia; Malvestio, Irene

2017-05-01

Networks of coupled oscillators in chimera states are characterized by an intriguing interplay of synchronous and asynchronous motion. While chimera states were initially discovered in mathematical model systems, there is growing experimental and conceptual evidence that they manifest themselves also in natural and man-made networks. In real-world systems, however, synchronization and desynchronization are not only important within individual networks but also across different interacting networks. It is therefore essential to investigate if chimera states can be synchronized across networks. To address this open problem, we use the classical setting of ring networks of non-locally coupled identical phase oscillators. We apply diffusive drive-response couplings between pairs of such networks that individually show chimera states when there is no coupling between them. The drive and response networks are either identical or they differ by a variable mismatch in their phase lag parameters. In both cases, already for weak couplings, the coherent domain of the response network aligns its position to the one of the driver networks. For identical networks, a sufficiently strong coupling leads to identical synchronization between the drive and response. For non-identical networks, we use the auxiliary system approach to demonstrate that generalized synchronization is established instead. In this case, the response network continues to show a chimera dynamics which however remains distinct from the one of the driver. Hence, segregated synchronized and desynchronized domains in individual networks congregate in generalized synchronization across networks.

The Message Reporting System of the ATLAS DAQ System

CERN Document Server

Caprini, M; Kolos, S; 10th ICATPP Conference on Astroparticle, Particle, Space Physics, Detectors and Medical Physics Applications

2008-01-01

The Message Reporting System (MRS) in the ATLAS data acquisition system (DAQ) is one package of the Online Software which acts as a glue of various elements of DAQ, High Level Trigger (HLT) and Detector Control System (DCS). The aim of the MRS is to provide a facility which allows all software components in ATLAS to report messages to other components of the distributed DAQ system. The processes requiring a MRS are on one hand applications that report error conditions or information and on the other hand message processors that receive reported messages. A message reporting application can inject one or more messages into the MRS at any time. An application wishing to receive messages can subscribe to a message group according to defined criteria. The application receives messages that fulfill the subscription criteria when they are reported to MRS. The receiver message processing can consist of anything from simply logging the messages in a file/terminal to performing message analysis. The inter-process comm...

Outer Synchronization of Complex Networks by Impulse

International Nuclear Information System (INIS)

Sun Wen; Yan Zizong; Chen Shihua; Lü Jinhu

2011-01-01

This paper investigates outer synchronization of complex networks, especially, outer complete synchronization and outer anti-synchronization between the driving network and the response network. Employing the impulsive control method which is uncontinuous, simple, efficient, low-cost and easy to implement in practical applications, we obtain some sufficient conditions of outer complete synchronization and outer anti-synchronization between two complex networks. Numerical simulations demonstrate the effectiveness of the proposed impulsive control scheme. (general)

Hand hygiene posters: motivators or mixed messages?

Science.gov (United States)

Jenner, E A; Jones, F; Fletcher, B C; Miller, L; Scott, G M

2005-07-01

Poster campaigns regarding hand hygiene are commonly used by infection control teams to improve practice, yet little is known of the extent to which they are based on established theory or research. This study reports on the content analysis of hand hygiene posters (N=69) and their messages (N=75) using message-framing theory. The results showed that posters seldom drew on knowledge about effective ways to frame messages. Frequently, they simply conveyed information 'telling' rather than 'selling' and some of this was confusing. Most posters were not designed to motivate, and some conveyed mixed messages. Few used fear appeals. Hand hygiene posters could have a greater impact if principles of message framing were utilized in their design. Suggestions for gain-framed messages are offered, but these need to be tested empirically.

Chaos synchronization between Chen system and Genesio system

International Nuclear Information System (INIS)

Wu Xianyong; Guan Zhihong; Wu Zhengping; Li Tao

2007-01-01

This Letter presents two synchronization schemes between two different chaotic systems. Active control synchronization and adaptive synchronization between Chen system and Genesio system are studied, different controllers are designed to synchronize the drive and response systems, active control synchronization is used when system parameters are known; adaptive synchronization is employed when system parameters are unknown or uncertain. Simulation results show the effectiveness of the proposed schemes

Preventing messaging queue deadlocks in a DMA environment

Science.gov (United States)

Blocksome, Michael A; Chen, Dong; Gooding, Thomas; Heidelberger, Philip; Parker, Jeff

2014-01-14

Embodiments of the invention may be used to manage message queues in a parallel computing environment to prevent message queue deadlock. A direct memory access controller of a compute node may determine when a messaging queue is full. In response, the DMA may generate and interrupt. An interrupt handler may stop the DMA and swap all descriptors from the full messaging queue into a larger queue (or enlarge the original queue). The interrupt handler then restarts the DMA. Alternatively, the interrupt handler stops the DMA, allocates a memory block to hold queue data, and then moves descriptors from the full messaging queue into the allocated memory block. The interrupt handler then restarts the DMA. During a normal messaging advance cycle, a messaging manager attempts to inject the descriptors in the memory block into other messaging queues until the descriptors have all been processed.

Synchronization of indirectly coupled Lorenz oscillators

Indian Academy of Sciences (India)

Synchronization of indirectly coupled Lorenz oscillators: An experimental study. Amit Sharma Manish Dev Shrimali. Synchronization, Coupled Systems and Networks Volume 77 Issue 5 November 2011 pp 881-889 ... The in-phase and anti-phase synchronization of indirectly coupled chaotic oscillators reported in Phys. Rev ...

A synchronous game for binary constraint systems

Science.gov (United States)

Kim, Se-Jin; Paulsen, Vern; Schafhauser, Christopher

2018-03-01

Recently, Slofstra proved that the set of quantum correlations is not closed. We prove that the set of synchronous quantum correlations is not closed, which implies his result, by giving an example of a synchronous game that has a perfect quantum approximate strategy but no perfect quantum strategy. We also exhibit a graph for which the quantum independence number and the quantum approximate independence number are different. We prove new characterisations of synchronous quantum approximate correlations and synchronous quantum spatial correlations. We solve the synchronous approximation problem of Dykema and the second author, which yields a new equivalence of Connes' embedding problem in terms of synchronous correlations.

Control synchronization of differential mobile robots

NARCIS (Netherlands)

Nijmeijer, H.; Rodriguez Angeles, A.; Allgoewer, F.

2004-01-01

In this paper a synchronization controller for differential mobile robots is proposed. The synchronization goal is to control the angular position of each wheel to a desired trajectory and at the same time the differential (or synchronization) error between the angular positions of the two wheels.

Frame Synchronization Without Attached Sync Markers

Science.gov (United States)

Hamkins, Jon

2011-01-01

We describe a method to synchronize codeword frames without making use of attached synchronization markers (ASMs). Instead, the synchronizer identifies the code structure present in the received symbols, by operating the decoder for a handful of iterations at each possible symbol offset and forming an appropriate metric. This method is computationally more complex and doesn't perform as well as frame synchronizers that utilize an ASM; nevertheless, the new synchronizer acquires frame synchronization in about two seconds when using a 600 kbps software decoder, and would take about 15 milliseconds on prototype hardware. It also eliminates the need for the ASMs, which is an attractive feature for short uplink codes whose coding gain would be diminished by the overheard of ASM bits. The lack of ASMs also would simplify clock distribution for the AR4JA low-density parity-check (LDPC) codes and adds a small amount to the coding gain as well (up to 0.2 dB).

Analysis of remote synchronization in complex networks

Science.gov (United States)

Gambuzza, Lucia Valentina; Cardillo, Alessio; Fiasconaro, Alessandro; Fortuna, Luigi; Gómez-Gardeñes, Jesus; Frasca, Mattia

2013-12-01

A novel regime of synchronization, called remote synchronization, where the peripheral nodes form a phase synchronized cluster not including the hub, was recently observed in star motifs [Bergner et al., Phys. Rev. E 85, 026208 (2012)]. We show the existence of a more general dynamical state of remote synchronization in arbitrary networks of coupled oscillators. This state is characterized by the synchronization of pairs of nodes that are not directly connected via a physical link or any sequence of synchronized nodes. This phenomenon is almost negligible in networks of phase oscillators as its underlying mechanism is the modulation of the amplitude of those intermediary nodes between the remotely synchronized units. Our findings thus show the ubiquity and robustness of these states and bridge the gap from their recent observation in simple toy graphs to complex networks.

SMS Messaging Applications

CERN Document Server

Pero, Nicola

2009-01-01

Cell phones are the most common communication device on the planet, and Short Message Service (SMS) is the chief channel for companies to offer services, accept requests, report news, and download binary files over cell phones. This guide describes the protocols and best practices (things that ensure you won't get sued or lose your right to offer a service) you need to know to make SMS messaging part of an organizational service. Issues such as character sets, differences among vendors, common practices in Europe and North America, and API choices are covered.

AMS: Area Message Service for SLC

International Nuclear Information System (INIS)

Crane, M.; Mackenzie, R.; Millsom, D.; Zelazny, M.

1993-04-01

The Area Message Service (AMS) is a TCP/IP based messaging service currently in use at SLAC. A number of projects under development here at SLAC require and application level interface to the 4.3BSD UNIX socket level communications functions using TCP/IP over ethernet. AMS provides connection management, solicited message transfer, unsolicited message transfer, and asynchronous notification of pending messages. AMS is written completely in ANSI 'C' and is currently portable over three hardware/operating system/network manager platforms, VAX/VMS/Multinet, PC/MS-DOS/Pathworks, VME 68K/pSOS/pNA. The basic architecture is a client-server connection where either end of the interface may be the server. This allows for connections and data flow to be initiated from either end of the interface. Included in the paper are details concerning the connection management, the handling of the multi-platform code, and the implementation process

A no-key-exchange secure image sharing scheme based on Shamir's three-pass cryptography protocol and the multiple-parameter fractional Fourier transform.

Science.gov (United States)

Lang, Jun

2012-01-30

In this paper, we propose a novel secure image sharing scheme based on Shamir's three-pass protocol and the multiple-parameter fractional Fourier transform (MPFRFT), which can safely exchange information with no advance distribution of either secret keys or public keys between users. The image is encrypted directly by the MPFRFT spectrum without the use of phase keys, and information can be shared by transmitting the encrypted image (or message) three times between users. Numerical simulation results are given to verify the performance of the proposed algorithm.

Getting the Message? Native Reactive Electrophiles Pass Two Out of Three Thresholds to be Bona Fide Signaling Mediators.

Science.gov (United States)

Poganik, Jesse R; Long, Marcus J C; Aye, Yimon

2018-05-01

Precision cell signaling activities of reactive electrophilic species (RES) are arguably among the most poorly-understood means to transmit biological messages. Latest research implicates native RES to be a chemically-distinct subset of endogenous redox signals that influence cell decision making through non-enzyme-assisted modifications of specific proteins. Yet, fundamental questions remain regarding the role of RES as bona fide second messengers. Here, we lay out three sets of criteria we feel need to be met for RES to be considered as true cellular signals that directly mediate information transfer by modifying "first-responding" sensor proteins. We critically assess the available evidence and define the extent to which each criterion has been fulfilled. Finally, we offer some ideas on the future trajectories of the electrophile signaling field taking inspiration from work that has been done to understand canonical signaling mediators. Also see the video abstract here: https://youtu.be/rG7o0clVP0c. © 2018 WILEY Periodicals, Inc.

RUN LENGTH SYNCHRONIZATION TECHNIQUES

Science.gov (United States)

An important aspect of digital communications is the problem of determining efficient methods for acquiring block synchronization . In this paper we...utilizes an N-digit sync sequence as prefix to the data blocks. The results of this study show that this technique is a practical method for acquiring block synchronization .

Complete synchronization of two Chen-Lee systems

International Nuclear Information System (INIS)

Sheu, L-J; Chen, J-H; Chen, H-K; Tam, L-M; Lao, S-K; Chen, W-C; Lin, K-T

2008-01-01

This study demonstrates that complete synchronization of two Chen-Lee chaotic systems can be easily achieved. The upper bound of the Chen-Lee chaotic system is estimated numerically. A controller is designed to synchronize two chaotic systems. Sufficient conditions for synchronization are obtained using Lyapunov's direct method. Two numerical examples are presented to verify the proposed synchronization approach

The influence of message framing, intention to quit smoking, and nicotine dependence on the persuasiveness of smoking cessation messages.

Science.gov (United States)

Moorman, Marjolein; van den Putte, Bas

2008-10-01

This study explores the combined effect of message framing, intention to quit smoking, and nicotine dependence on the persuasiveness of smoking cessation messages. Pre- and post-message measures of quit intention, attitude toward smoking cessation, and perceived behavioral control were taken in two separate waves from current cigarette smokers with varying levels of nicotine dependence (N=151). In the second wave, participants were randomly assigned to one of two groups. In the first group, participants read a smoking cessation message which emphasized the benefits of quitting (positive frame). In the second group participants read a message which emphasized the costs of not quitting (negative frame). Results show that smokers' intentions to quit smoking and their level of nicotine dependence jointly influence the persuasiveness of positive and negative message frames. When nicotine dependence and quitting intention are both high, a negative frame works best. Conversely, a positive frame is preferable when nicotine dependence or quitting intention is low. Smokers' level of processing is proposed as the underlying mechanism explaining the different effects of message frames.

Robust finite-time chaos synchronization of uncertain permanent magnet synchronous motors.

Science.gov (United States)

Chen, Qiang; Ren, Xuemei; Na, Jing

2015-09-01

In this paper, a robust finite-time chaos synchronization scheme is proposed for two uncertain third-order permanent magnet synchronous motors (PMSMs). The whole synchronization error system is divided into two cascaded subsystems: a first-order subsystem and a second-order subsystem. For the first subsystem, we design a finite-time controller based on the finite-time Lyapunov stability theory. Then, according to the backstepping idea and the adding a power integrator technique, a second finite-time controller is constructed recursively for the second subsystem. No exogenous forces are required in the controllers design but only the direct-axis (d-axis) and the quadrature-axis (q-axis) stator voltages are used as manipulated variables. Comparative simulations are provided to show the effectiveness and superior performance of the proposed method. Copyright © 2015 ISA. Published by Elsevier Ltd. All rights reserved.

Synchronization in Quantum Key Distribution Systems

Directory of Open Access Journals (Sweden)

Anton Pljonkin

2017-10-01

Full Text Available In the description of quantum key distribution systems, much attention is paid to the operation of quantum cryptography protocols. The main problem is the insufficient study of the synchronization process of quantum key distribution systems. This paper contains a general description of quantum cryptography principles. A two-line fiber-optic quantum key distribution system with phase coding of photon states in transceiver and coding station synchronization mode was examined. A quantum key distribution system was built on the basis of the scheme with automatic compensation of polarization mode distortions. Single-photon avalanche diodes were used as optical radiation detecting devices. It was estimated how the parameters used in quantum key distribution systems of optical detectors affect the detection of the time frame with attenuated optical pulse in synchronization mode with respect to its probabilistic and time-domain characteristics. A design method was given for the process that detects the time frame that includes an optical pulse during synchronization. This paper describes the main quantum communication channel attack methods by removing a portion of optical emission. This paper describes the developed synchronization algorithm that takes into account the time required to restore the photodetector’s operation state after the photon has been registered during synchronization. The computer simulation results of the developed synchronization algorithm were analyzed. The efficiency of the developed algorithm with respect to synchronization process protection from unauthorized gathering of optical emission is demonstrated herein.

Improved Message Authentication and Confidentiality Checking

International Nuclear Information System (INIS)

Ismail Jabiullah, M.; Abdullah Al-Shamim, M.; Lutfar Rahman, M.

2005-01-01

The most confusing areas of the secured network communications are the message authentication and confidentiality checking. The attacks and the counter measures have become so convoluted that the users in this area begin to account for all contingencies. Two session-key generation techniques are used here to generate two separate session keys K 1 and K 2 ; and both the sender and the reveiver share these keys for higher degree of authentication and confidentiality. For this, the message is first encrypted by the key K 1 , and then the intermediary message authenticatin code (MAC) is generated by encrypting the encrypted message using the key K 2 . Then, the encrypted message and the intermediary MAC is again encrypted by using the K 2 and concatenated with the encrypted message and sent to the destination. At the receiving end, first, the received ciphertext is encrypted by using key K 2 and compared to the received MAC. The received ciphertext again is decrypted by the key K 2 and compared with the first decrypted MAC twice by the key K 2 . The plaintext is obtained by decrypting the received ciphertext first by K 2 and then by K 1 , using the corresponding decryption techniques respectively. The encryption techniques with key K 2 provides the authentication and with key K 1 provides the confidentiality checking of the transmitted message. The developed technique can be applied to both academic and commercial applications in online or offline electronic transactions for security.(authors)

A one-way text messaging intervention for obesity.

Science.gov (United States)

Ahn, Ahleum; Choi, Jaekyung

2016-04-01

Worldwide, there has been a startling increase in the number of people who are obese or overweight. Obesity increases the risk of cardiovascular disease and overall mortality. Mobile phone messaging is an important means of human communication globally. Because the mobile phone can be used anywhere at any time, mobile phone messaging has the potential to manage obesity. We investigated the effectiveness of a one-way text messaging intervention for obesity. Participants' body mass index and waist circumference were measured at the beginning of the programme and again after 12 weeks. The text message group received text messages about exercise, dietary intake, and general information about obesity three times a week, while the control group did not receive any text messages from the study. Of the 80 participants, 25 subjects in the text message group and 29 participants in the control group completed the study. After adjusting for baseline body mass index, the body mass index was significantly lower in the text message group than in the control group (27.9 vs. 28.3; p = 0.02). After adjusting for the baseline waist circumference, the difference of waist circumference between the text message group and control group was not significant (93.4 vs. 94.6; p = 0.13). The one-way text messaging intervention was a simple and effective way to manage obesity. The one-way text messaging intervention may be a useful method for lifestyle modification in obese subjects. © The Author(s) 2015.

Persuasive messages. Development of persuasive messages may help increase mothers' compliance of their children's immunization schedule.

Science.gov (United States)

Gore, P; Madhavan, S; Curry, D; McClurg, G; Castiglia, M; Rosenbluth, S A; Smego, R A

1998-01-01

Effective immunization campaigns can be designed by determining which persuasion strategy is most effective in attracting the attention of mothers of preschoolers. The authors assess the impact of three persuasional strategies: fear-arousal, motherhood-arousal, and rational messages, on mothers of preschoolers who are late for their immunizations. The fear-arousal message was found to be most effective, followed by the motherhood-arousal, and then the rational message, in attracting mothers' attention to their child's immunization status.

Empowerment in the process of health messaging for rural low-income mothers: an exploratory message design project.

Science.gov (United States)

Aldoory, Linda; Braun, Bonnie; Maring, Elisabeth Fost; Duggal, Mili; Briones, Rowena Lynn

2015-01-01

Rural, low-income mothers face challenges to their health equal to or greater than those of low-income mothers from urban areas. This study put health message design into the hands of low-income rural mothers. The current study filled a research gap by analyzing a participatory process used to design health messages tailored to the everyday lives of rural low-income mothers. A total of forty-three mothers participated in nine focus groups, which were held from 2012 to 2013, in eight states. The mothers were from different racial and ethnic backgrounds. Participants discussed food security, physical activity, and oral health information. They created messages by considering several elements: visuals, length of message, voice/perspective, self-efficacy and personal control, emotional appeals, positive and negative reinforcements, and steps to health behavior change. This study was innovative in its focus on empowerment as a key process to health message design.

Crafting a Real-Time Information Aggregator for Mobile Messaging

Directory of Open Access Journals (Sweden)

Jenq-Shiou Leu

2010-01-01

Full Text Available Mobile messaging is evolving beyond SMS (Short Message Service text messaging with the introduction of MMS (Multimedia Messaging Service. In the past, such a scheme is used for peer-to-peer communication. Messages are generally displayed on a cellular phone with a limited-sized screen. However, such a visualizing process is not suitable to broadcast real-time SMS/MMS messages to people in public. To facilitate the instancy and publicity, we develop a real-time information aggregator—Visualizing SMS and MMS Messages System (VSMMS—to realize the concept by integrating SMS and MMS messaging over GSM/GPRS/UMTS onto a remote display device. The device exhibits messages on a larger display device in public. VSMMS features a revolutionized variation of mass media broadcasting. In this paper, we practically illustrate how to design and implement VSMMS and use a M/M/1 model to conduct a theoretical analysis about the message delay in the system queue. Meanwhile, we make an empirical performance evaluation about the message transmission time over different networks.

Synchronization of hyperchaotic oscillators

DEFF Research Database (Denmark)

Tamasevicius, A.; Cenys, A.; Mykolaitis, G.

1997-01-01

Synchronization of chaotic oscillators is believed to have promising applications in secure communications. Hyperchaotic systems with multiple positive Lyapunov exponents (LEs) have an advantage over common chaotic systems with only one positive LE. Three different types of hyperchaotic electronic...... oscillators are investigated demonstrating synchronization by means of only one properly selected variable....

V123 Beam Synchronous Encoder Module

International Nuclear Information System (INIS)

Kerner, T.; Conkling, C. R.; Oerter, B.

1999-01-01

The V123 Synchronous Encoder Module transmits events to distributed trigger modules and embedded decoders around the RHIC rings where they are used to provide beam instrumentation triggers [1,2,3]. The RHIC beam synchronous event link hardware is mainly comprised of three VMEbus board designs, the central input modules (V201), and encoder modules (V123), and the distributed trigger modules (V124). Two beam synchronous links, one for each ring, are distributed via fiberoptic and fanned out via twisted wire pair cables. The V123 synchronizes with the RF system clock derived from the beam bucket frequency and a revolution fiducial pulse. The RF system clock is used to create the beam synchronous event link carrier and events are synchronized with the rotation fiducial. A low jitter RF clock is later recovered from this carrier by phase lock loops in the trigger modules. Prioritized hardware and software triggers fill up to 15 beam event code transmission slots per revolution while tracking the ramping RF acceleration frequency and storage frequency. The revolution fiducial event is always the first event transmitted which is used to synchronize the firing of the abort kicker and to locate the first bucket for decoders distributed about the ring

AMS: Area Message Service for SLC

International Nuclear Information System (INIS)

Crane, M.; Mackenzie, R.; Millsom, D.; Zelazny, M.

1993-01-01

The Area Message Service (AMS) is a TCP/IP based messaging service currently in use at SLAC. A number of projects under development here at SLAC require an application level interface to the 4.3BSD UNIX socket level communications functions using TCP/IP over ethernet. AMS provides connection management, solicited message transfer, unsolicited message transfer, and asynchronous notification of pending messages. AMS is written completely in ANSI open-quote C close-quote and is currently portable over three hardware/operating system/network manager platforms, VAX/VMS/Multinet, PC/MS-DOS/Pathworks, VME 68K/pSOS/pNA. The basic architecture is a client-server connection where either end of the interface may be the server. This allows for connections and data flow to be initiated from either end of the interface. Included in the paper are details concerning the connection management, the handling of the multi-platform code, and the implementation process

Does perceived risk influence the effects of message framing? Revisiting the link between prospect theory and message framing.

Science.gov (United States)

Van 't Riet, Jonathan; Cox, Anthony D; Cox, Dena; Zimet, Gregory D; De Bruijn, Gert-Jan; Van den Putte, Bas; De Vries, Hein; Werrij, Marieke Q; Ruiter, Robert A C

2016-12-01

Health-promoting messages can be framed in terms of the beneficial consequences of healthy behaviour (gain-framed messages) or the detrimental consequences of unhealthy behaviour (loss-framed messages). An influential notion holds that the perceived risk associated with the recommended behaviour determines the relative persuasiveness of gain- and loss-framed messages. This 'risk-framing hypothesis', which was derived from prospect theory, has been central to health message-framing research for the better part of two decades and has enduring appeal to researchers and practitioners. It has found its way into several health communication handbooks and is communicated to the general public. The present article examines the validity of the risk-framing hypothesis anew by providing a review of the health message-framing literature. In spite of its ongoing appeal, we conclude that the hypothesis has severe theoretical flaws. In addition, we find that the empirical evidence in favour of the hypothesis is weak and inconsistent. It seems that, in applying prospect theory's tenets to a health-promotion context, some of the theory's key aspects have been lost in translation. At the close of the article, we offer a research agenda for the future, arguing that, above all, new methodology is needed to bring the message-framing literature further.

Factors influencing message dissemination through social media

Science.gov (United States)

Zheng, Zeyu; Yang, Huancheng; Fu, Yang; Fu, Dianzheng; Podobnik, Boris; Stanley, H. Eugene

2018-06-01

Online social networks strongly impact our daily lives. An internet user (a "Netizen") wants messages to be efficiently disseminated. The susceptible-infected-recovered (SIR) dissemination model is the traditional tool for exploring the spreading mechanism of information diffusion. We here test our SIR-based dissemination model on open and real-world data collected from Twitter. We locate and identify phase transitions in the message dissemination process. We find that message content is a stronger factor than the popularity of the sender. We also find that the probability that a message will be forwarded has a threshold that affects its ability to spread, and when the probability is above the threshold the message quickly achieves mass dissemination.

System and method to allow a synchronous motor to successfully synchronize with loads that have high inertia and/or high torque

Science.gov (United States)

Melfi, Michael J.

2015-10-20

A mechanical soft-start type coupling is used as an interface between a line start, synchronous motor and a heavy load to enable the synchronous motor to bring the heavy load up to or near synchronous speed. The soft-start coupling effectively isolates the synchronous motor from the load for enough time to enable the synchronous motor to come up to full speed. The soft-start coupling then brings the load up to or near synchronous speed.

Investigating the impact of viral message appeal and message credibility on consumer attitude toward the brand

Directory of Open Access Journals (Sweden)

Esmaeilpour Majid

2016-07-01

Full Text Available Due to the rapid growth of the Internet and use of e-commerce in the recent years, viral marketing has drawn the attention of manufacturing and service organizations. However, no research has been conducted to examine the impact of message appeal and message source credibility on consumers’ attitude with mediating role of intellectual involvement of consumers and their risk taking level. The aim of this study was to examine the impact of appeal and message source credibility on consumers’ attitude with mediating role of consumers’ intellectual involvement and their risk taking level. The population of this study includes consumers of mobile phones (Samsung, Sony, Nokia, LG and iPhone in the Bushehr city (Iran. As the population of the study is unlimited, 430 questionnaires were distributed using available sampling method, and 391 questionnaires were collected and analyzed. Using structural equation modeling, we analysed the data through smart PLS software. The results show that the appeal and credibility of the message source impact the consumer attitudes toward the brand. We also found that the intellectual involvement of consumers plays the mediating role in the relationship between message appeal and consumer attitudes toward brands. In the relationship between message source credibility and customer attitude towards the brand, the level of risk taking of people has no mediating role.

Effects of frustration on explosive synchronization

Science.gov (United States)

Huang, Xia; Gao, Jian; Sun, Yu-Ting; Zheng, Zhi-Gang; Xu, Can

2016-12-01

In this study, we consider the emergence of explosive synchronization in scale-free networks by considering the Kuramoto model of coupled phase oscillators. The natural frequencies of oscillators are assumed to be correlated with their degrees and frustration is included in the system. This assumption can enhance or delay the explosive transition to synchronization. Interestingly, a de-synchronization phenomenon occurs and the type of phase transition is also changed. Furthermore, we provide an analytical treatment based on a star graph, which resembles that obtained in scale-free networks. Finally, a self-consistent approach is implemented to study the de-synchronization regime. Our findings have important implications for controlling synchronization in complex networks because frustration is a controllable parameter in experiments and a discontinuous abrupt phase transition is always dangerous in engineering in the real world.

Management and Archiving e-mail Messages in Governmental Organization

OpenAIRE

Ashraf Mohamed A.Mohsen

2006-01-01

The study deals great issue of digital preservation that is e-mail archiving, it covered all aspects of the topic; it discuss: e-mail system, components of e-mail message, advantages and disadvantages of e-mail, official e-mail messages, management of e-mail messages, organizing and arrangement of e-mail messages, keeping and deleting messages, archiving e-mail messages, and some related issues like: privacy and security.

The influence of message framing, intention to quit smoking, and nicotine dependence on the persuasiveness of smoking cessation messages

NARCIS (Netherlands)

Moorman, M.; van den Putte, B.

2008-01-01

This study explores the combined effect of message framing, intention to quit smoking, and nicotine dependence on the persuasiveness of smoking cessation messages. Pre- and post-message measures of quit intention, attitude toward smoking cessation, and perceived behavioral control were taken in two

Model Checking a Self-Stabilizing Distributed Clock Synchronization Protocol for Arbitrary Digraphs

Science.gov (United States)

Malekpour, Mahyar R.

2011-01-01

This report presents the mechanical verification of a self-stabilizing distributed clock synchronization protocol for arbitrary digraphs in the absence of faults. This protocol does not rely on assumptions about the initial state of the system, other than the presence of at least one node, and no central clock or a centrally generated signal, pulse, or message is used. The system under study is an arbitrary, non-partitioned digraph ranging from fully connected to 1-connected networks of nodes while allowing for differences in the network elements. Nodes are anonymous, i.e., they do not have unique identities. There is no theoretical limit on the maximum number of participating nodes. The only constraint on the behavior of the node is that the interactions with other nodes are restricted to defined links and interfaces. This protocol deterministically converges within a time bound that is a linear function of the self-stabilization period.

Grid Synchronization of Wind Turbine Converters under Transient Grid Faults using a Double Synchronous Reference Frame PLL

DEFF Research Database (Denmark)

Teodorescu, Remus; Blaabjerg, Frede; Rodriguez, P.

2008-01-01

This work employs the Double Synchronous Reference Frame PLL (DSRF-PLL) as an effective method for grid synchronization of WT's power converters in the presence of transient faults in the grid. The DSRF-PLL exploits a dual synchronous reference frame voltage characterization, adding a decoupling...... network to a standard SRF-PLL in order to effectively separate the positive- and negative-sequence voltage components in a fast and accurate way. Experimental evaluation of the proposed grid synchronization method and simulations regarding its application to ride through transient faults verify...

40 CFR 93.128 - Traffic signal synchronization projects.

Science.gov (United States)

2010-07-01

... 40 Protection of Environment 20 2010-07-01 2010-07-01 false Traffic signal synchronization... synchronization projects. Traffic signal synchronization projects may be approved, funded, and implemented without... include such regionally significant traffic signal synchronization projects. ...

Improving Type Error Messages in OCaml

Directory of Open Access Journals (Sweden)

Arthur Charguéraud

2015-12-01

Full Text Available Cryptic type error messages are a major obstacle to learning OCaml or other ML-based languages. In many cases, error messages cannot be interpreted without a sufficiently-precise model of the type inference algorithm. The problem of improving type error messages in ML has received quite a bit of attention over the past two decades, and many different strategies have been considered. The challenge is not only to produce error messages that are both sufficiently concise and systematically useful to the programmer, but also to handle a full-blown programming language and to cope with large-sized programs efficiently. In this work, we present a modification to the traditional ML type inference algorithm implemented in OCaml that, by significantly reducing the left-to-right bias, allows us to report error messages that are more helpful to the programmer. Our algorithm remains fully predictable and continues to produce fairly concise error messages that always help making some progress towards fixing the code. We implemented our approach as a patch to the OCaml compiler in just a few hundred lines of code. We believe that this patch should benefit not just to beginners, but also to experienced programs developing large-scale OCaml programs.

Partial Synchronization Manifolds for Linearly Time-Delay Coupled Systems

OpenAIRE

Steur, Erik; van Leeuwen, Cees; Michiels, Wim

2014-01-01

Sometimes a network of dynamical systems shows a form of incomplete synchronization characterized by synchronization of some but not all of its systems. This type of incomplete synchronization is called partial synchronization. Partial synchronization is associated with the existence of partial synchronization manifolds, which are linear invariant subspaces of C, the state space of the network of systems. We focus on partial synchronization manifolds in networks of system...

The WLCG Messaging Service and its Future

International Nuclear Information System (INIS)

Cons, Lionel; Paladin, Massimo

2012-01-01

Enterprise messaging is seen as an attractive mechanism to simplify and extend several portions of the Grid middleware, from low level monitoring to experiments dashboards. The production messaging service currently used by WLCG includes four tightly coupled brokers operated by EGI (running Apache ActiveMQ and designed to host the Grid operational tools such as SAM) as well as two dedicated services for ATLAS-DDM and experiments dashboards (currently also running Apache ActiveMQ). In the future, this service is expected to grow in numbers of applications supported, brokers and technologies. The WLCG Messaging Roadmap identified three areas with room for improvement (security, scalability and availability/reliability) as well as ten practical recommendations to address them. This paper describes a messaging service architecture that is in line with these recommendations as well as a software architecture based on reusable components that ease interactions with the messaging service. These two architectures will support the growth of the WLCG messaging service.

Synchronous machines. General principles and structures; Machines synchrones. Principes generaux et structures

Energy Technology Data Exchange (ETDEWEB)

Ben Ahmed, H.; Feld, G.; Multon, B. [Ecole Normale Superieure de Cachan, Lab. SATIE, Systemes et Applications des Technologies de l' Information et de l' Energie, UMR CNRS 8029, 94 (France); Bernard, N. [Institut Universitaire de Saint-Nazaire, Institut de Recherche en Electrotechnique et Electronique de Nantes Atlantique (IREENA), 44 - Nantes (France)

2005-10-01

Power generation is mainly performed by synchronous rotating machines which consume about a third of the world primary energy. Electric motors used in industrial applications convert about two thirds of this electricity. Therefore, synchronous machines are present everywhere at different scales, from micro-actuators of few micro-watts to thermo-mechanical production units of more than 1 GW, and represent a large variety of structures which have in common the synchronism between the frequency of the power supply currents and the relative movement of the fixed part with respect to the mobile part. Since several decades, these machines are more and more used as variable speed motors with permanent magnets. The advances in power electronics have contributed to the widening of their use in various applications with a huge range of powers. This article presents the general principle of operation of electromechanical converters of synchronous type: 1 - electromechanical conversion in electromagnetic systems: basic laws and elementary structures (elementary structure, energy conversion cycle, case of a system working in linear magnetic regime), rotating fields structure (magneto-motive force and Ferraris theorem, superficial air gap permeance, air gap magnetic induction, case of a permanent magnet inductor, magnetic energy and electromagnetic torque, conditions for reaching a non-null average torque, application to common cases); 2 - constitution, operation modes and efficiency: constitution and main types of synchronous machines, efficiency - analysis by similarity laws (other expression of the electromagnetic torque, thermal limitation in permanent regime, scale effects, effect of pole pairs number, examples of efficiencies and domains of use), operation modes. (J.S.)

Chaos synchronization based on contraction principle

International Nuclear Information System (INIS)

Wang Junwei; Zhou Tianshou

2007-01-01

This paper introduces contraction principle. Based on such a principle, a novel scheme is proposed to synchronize coupled systems with global diffusive coupling. A rigorous sufficient condition on chaos synchronization is derived. As an example, coupled Lorenz systems with nearest-neighbor diffusive coupling are investigated, and numerical simulations are given to validate the proposed synchronization approach

Generalized synchronization in discrete maps. New point of view on weak and strong synchronization

International Nuclear Information System (INIS)

Koronovskii, Alexey A.; Moskalenko, Olga I.; Shurygina, Svetlana A.; Hramov, Alexander E.

2013-01-01

In the present Letter we show that the concept of the generalized synchronization regime in discrete maps needs refining in the same way as it has been done for the flow systems Koronovskii et al. [Koronovskii AA, Moskalenko OI, Hramov AE. Nearest neighbors, phase tubes, and generalized synchronization. Phys Rev E 2011;84:037201]. We have shown that, in the general case, when the relationship between state vectors of the interacting chaotic maps are considered, the prehistory must be taken into account. We extend the phase tube approach to the systems with a discrete time coupled both unidirectionally and mutually and analyze the essence of the generalized synchronization by means of this technique. Obtained results show that the division of the generalized synchronization into the weak and the strong ones also must be reconsidered. Unidirectionally coupled logistic maps and Hénon maps coupled mutually are used as sample systems.

Injuries and medical issues in synchronized Olympic sports.

Science.gov (United States)

Mountjoy, Margo

2009-01-01

Spectators of the Olympic Games can enjoy a wide variety of sports, including strength, team, timed, endurance, and artistic sports. In the Olympic program, there are two synchronized events: synchronized diving and synchronized swimming. The precision of the synchronization of the athlete's movements and skills is an added feature of entertainment. Synchronized athletes have additional training requirements to perfect the synchronization of their skills. The physical demands on the athlete from the repetition of training required for the perfection of synchronization result in injuries unique to these sports. Although both traumatic and overuse injuries occur, overuse injuries are more common. As these disciplines are artistic, judged sports, these athletes also are susceptible to eating disorders and the female athlete triad. This article reviews the training regimen of these athletes and outlines the injuries and health concerns that are common in the synchronized sports.

Traffic signal synchronization.

Science.gov (United States)

Huang, Ding-wei; Huang, Wei-neng

2003-05-01

The benefits of traffic signal synchronization are examined within the cellular automata approach. The microsimulations of traffic flow are obtained with different settings of signal period T and time delay delta. Both numerical results and analytical approximations are presented. For undersaturated traffic, the green-light wave solutions can be realized. For saturated traffic, the correlation among the traffic signals has no effect on the throughput. For oversaturated traffic, the benefits of synchronization are manifest only when stochastic noise is suppressed.

Injuries in synchronized skating.

Science.gov (United States)

Dubravcic-Simunjak, S; Kuipers, H; Moran, J; Simunjak, B; Pecina, M

2006-06-01

Synchronized skating is a relatively new competitive sport and data about injuries in this discipline are lacking. Therefore the purpose of this study was to investigate the frequency and pattern of acute and overuse injuries in synchronized skaters. Before and during the World Synchronized Skating Championship 2004, a questionnaire inquiring about the frequency of injuries in this skating discipline was given to 23 participating teams. A total of 514 women and 14 men senior skaters completed the questionnaires (100 % response). Two hundred and eighteen (42.4 %) female and 6 (42.9 %) male skaters had suffered from acute injuries during their synchronized skating career. As some skaters had suffered from more than one injury, the total number of acute injuries in females was 398 and in males 14. In female skaters 19.8 % of acute injuries were head injuries, 7.1 % trunk, 33.2 % upper, and 39.9 % lower extremity injuries. In male skaters 14.3 % were head injuries, 28.6 % upper, and 57.1 % lower extremity injuries, with no report of trunk injuries. Sixty-nine female and 2 male skaters had low back problems and 112 female and 2 male skaters had one or more overuse syndromes during their skating career. Of 155 overuse injuries in female skaters, 102 (65.8 %) occurred during their figure skating career, while 53 injuries (34.2 %) only occurred when they skated in synchronized skating teams. In male skaters, out of 5 overuse injuries, 4 (80 %) occurred in their figure skating career, while 1 (20 %) occurred during their synchronized skating career. Out of the total of 412 injuries, 338 (82 %) occurred during on-ice practice, while 74 (18 %) happened during off-ice training. Ninety-one (26.9 %) acute injures occurred while practicing individual elements, and 247 (73.1 %) on-ice injuries occurred while practicing different team elements. We conclude that injuries in synchronized skating should be of medical concern due to an increasing number of acute injuries, especially

Measures of Quantum Synchronization in Continuous Variable Systems

Science.gov (United States)

Mari, A.; Farace, A.; Didier, N.; Giovannetti, V.; Fazio, R.

2013-09-01

We introduce and characterize two different measures which quantify the level of synchronization of coupled continuous variable quantum systems. The two measures allow us to extend to the quantum domain the notions of complete and phase synchronization. The Heisenberg principle sets a universal bound to complete synchronization. The measure of phase synchronization is, in principle, unbounded; however, in the absence of quantum resources (e.g., squeezing) the synchronization level is bounded below a certain threshold. We elucidate some interesting connections between entanglement and synchronization and, finally, discuss an application based on quantum optomechanical systems.

Analyzing the Social Knowledge Construction Behavioral Patterns of an Online Synchronous Collaborative Discussion Instructional Activity Using an Instant Messaging Tool: A Case Study

Science.gov (United States)

Hou, Huei-Tse; Wu, Sheng-Yi

2011-01-01

Online discussions have been widely utilized as an educational activity, and much research has been conducted on the process and behaviors involved in asynchronous discussions. However, research on behavioral patterns in learners' synchronous discussions, including the process of social knowledge construction and project coordination is limited.…

Nonlinearity induced synchronization enhancement in mechanical oscillators

Science.gov (United States)

Czaplewski, David A.; Lopez, Omar; Guest, Jeffrey R.; Antonio, Dario; Arroyo, Sebastian I.; Zanette, Damian H.

2018-05-08

An autonomous oscillator synchronizes to an external harmonic force only when the forcing frequency lies within a certain interval, known as the synchronization range, around the oscillator's natural frequency. Under ordinary conditions, the width of the synchronization range decreases when the oscillation amplitude grows, which constrains synchronized motion of micro- and nano-mechanical resonators to narrow frequency and amplitude bounds. The present invention shows that nonlinearity in the oscillator can be exploited to manifest a regime where the synchronization range increases with an increasing oscillation amplitude. The present invention shows that nonlinearities in specific configurations of oscillator systems, as described herein, are the key determinants of the effect. The present invention presents a new configuration and operation regime that enhances the synchronization of micro- and nano-mechanical oscillators by capitalizing on their intrinsic nonlinear dynamics.

Adaptive H∞ Chaos Anti-synchronization

International Nuclear Information System (INIS)

Ahn, Choon Ki

2010-01-01

A new adaptive H ∞ anti-synchronization (AHAS) method is proposed for chaotic systems in the presence of unknown parameters and external disturbances. Based on the Lyapunov theory and linear matrix inequality formulation, the AHAS controller with adaptive laws of unknown parameters is derived to not only guarantee adaptive anti-synchronization but also reduce the effect of external disturbances to an H ∞ norm constraint. As an application of the proposed AHAS method, the H ∞ anti-synchronization problem for Genesio–Tesi chaotic systems is investigated. (general)

Comment ameliorer la selection et le traitement des messages verbaux? (How to Improve the Selection and Processing of Verbal Messages)

National Research Council Canada - National Science Library

Rivenez, Marie; Darwin, Chris; Guillaume, Anne

2005-01-01

L'objectif de cette recherche est d'ameliorer la selection des messages verbaux. Nous cherchons a determiner les facteurs influencant le traitement d'un message verbal lorsque l'attention est portee sur un autre message...

Randomized, controlled trial comparing synchronized intermittent mandatory ventilation and synchronized intermittent mandatory ventilation plus pressure support in preterm infants.

Science.gov (United States)

Reyes, Zenaida C; Claure, Nelson; Tauscher, Markus K; D'Ugard, Carmen; Vanbuskirk, Silvia; Bancalari, Eduardo

2006-10-01

Prolonged mechanical ventilation is associated with lung injury in preterm infants. In these infants, weaning from synchronized intermittent mandatory ventilation may be delayed by their inability to cope with increased respiratory loads. The addition of pressure support to synchronized intermittent mandatory ventilation can offset these loads and may facilitate weaning. The purpose of this work was to compare synchronized intermittent mandatory ventilation and synchronized intermittent mandatory ventilation plus pressure support in weaning from mechanical ventilation and the duration of supplemental oxygen dependency in preterm infants with respiratory failure. Preterm infants weighing 500 to 1000 g at birth who required mechanical ventilation during the first postnatal week were randomly assigned to synchronized intermittent mandatory ventilation or synchronized intermittent mandatory ventilation plus pressure support. In both groups, weaning followed a set protocol during the first 28 days. Outcomes were assessed during the first 28 days and until discharge or death. There were 107 infants enrolled (53 synchronized intermittent mandatory ventilation plus pressure support and 54 synchronized intermittent mandatory ventilation). Demographic and perinatal data, mortality, and morbidity did not differ between groups. During the first 28 days, infants in the synchronized intermittent mandatory ventilation plus pressure support group reached minimal ventilator settings and were extubated earlier than infants in the synchronized intermittent mandatory ventilation group. Total duration of mechanical ventilation, duration of oxygen dependency, and oxygen need at 36 weeks' postmenstrual age alone or combined with death did not differ between groups. However, infants in synchronized intermittent mandatory ventilation plus pressure support within the 700- to 1000-g birth weight strata had a shorter oxygen dependency. The results of this study suggest that the addition of

Spontaneous group synchronization of movements and respiratory rhythms.

Directory of Open Access Journals (Sweden)

Erwan Codrons

Full Text Available We tested whether pre-assigned arm movements performed in a group setting spontaneously synchronized and whether synchronization extended to heart and respiratory rhythms. We monitored arm movements, respiration and electrocardiogram at rest and during spontaneous, music and metronome-associated arm-swinging. No directions were given on whether or how the arm swinging were to be synchronized between participants or with the external cues. Synchronization within 3 groups of 10 participants studied collectively was compared with pseudo-synchronization of 3 groups of 10 participants that underwent an identical protocol but in an individual setting. Motor synchronization was found to be higher in the collective groups than in the individuals for the metronome-associated condition. On a repetition of the protocol on the following day, motor synchronization in the collective groups extended to the spontaneous, un-cued condition. Breathing was also more synchronized in the collective groups than in the individuals, particularly at rest and in the music-associated condition. Group synchronization occurs without explicit instructions, and involves both movements and respiratory control rhythms.

Vestibular hearing and neural synchronization.

Science.gov (United States)

Emami, Seyede Faranak; Daneshi, Ahmad

2012-01-01

Objectives. Vestibular hearing as an auditory sensitivity of the saccule in the human ear is revealed by cervical vestibular evoked myogenic potentials (cVEMPs). The range of the vestibular hearing lies in the low frequency. Also, the amplitude of an auditory brainstem response component depends on the amount of synchronized neural activity, and the auditory nerve fibers' responses have the best synchronization with the low frequency. Thus, the aim of this study was to investigate correlation between vestibular hearing using cVEMPs and neural synchronization via slow wave Auditory Brainstem Responses (sABR). Study Design. This case-control survey was consisted of twenty-two dizzy patients, compared to twenty healthy controls. Methods. Intervention comprised of Pure Tone Audiometry (PTA), Impedance acoustic metry (IA), Videonystagmography (VNG), fast wave ABR (fABR), sABR, and cVEMPs. Results. The affected ears of the dizzy patients had the abnormal findings of cVEMPs (insecure vestibular hearing) and the abnormal findings of sABR (decreased neural synchronization). Comparison of the cVEMPs at affected ears versus unaffected ears and the normal persons revealed significant differences (P < 0.05). Conclusion. Safe vestibular hearing was effective in the improvement of the neural synchronization.

Using Publish-Subscribe Messaging for System Status and Automation

Science.gov (United States)

Smith, Danford S.

2015-01-01

The NASA Goddard Mission Services Evolution Center (GMSEC) system is a message-based plug-and-play open system architecture used in many of NASA mission operations centers. This presentation will focus on the use of GMSEC standard messages to report and analyze the status of a system and enable the automation of the system's components. In GMSEC systems, each component reports its status using a keep-alive message and also publishes status and activities as log messages. In addition, the components can accept functional directive messages from the GMSEC message bus. Over the past several years, development teams have found ways to utilize these messages to create innovative display pages and increasingly sophisticated approaches to automation. This presentation will show the flexibility and value of the message-based approach to system awareness and automation.

Using Text-Messaging in the Secondary Classroom

Science.gov (United States)

Thomas, Kevin; Orthober, Corrie

2011-01-01

To examine the potential uses of and barriers to text-messaging in secondary schools, three classes (66 students) of high school students used their personal mobile phones to receive out of school, course-related text-messages from teachers. Forty-six students (70%) agreed to receive text-messages. Findings indicate that participants found…

Emotional flow in persuasive health messages.

Science.gov (United States)

Nabi, Robin L

2015-01-01

Overwhelmingly, the literature on the persuasive influence of emotions has focused on individual emotions, fear in particular, though some recent attention has been given to mixed emotions in persuasive appeals. Building on this newer wave of research, this article argues that instead of focusing on singular emotional states or collections of emotions evoked by a message, it might prove valuable to explore the flow, or evolution, of emotional experience over the course of exposure to a health message. The article offers a brief introduction to the concept of emotion, followed by a review of the state of the literature on the use of emotion in health messages. The concept of emotional flow is then introduced along with a consideration of how it has been tacitly incorporated into the study of emotional health messages. Finally, the utility of the concept of emotional flow is elaborated by articulating the ways in which it might be harnessed to facilitate the creation of more effective health messages, individually as well as across campaigns. The article concludes with an agenda for future research.

Matching Message Design and Depressed Cognition: An Exploration of Attention Patterns for Gain- and Loss-Framed Depression Help-Seeking Messages.

Science.gov (United States)

Lueck, Jennifer A

2017-07-01

Although disproportionally affected by depression, most depressed college students do not seek the help they need. Research has recently uncovered the potential negative effects of depression help-seeking messages if depressed cognition is not considered in the health message design process. It is unclear if depression determines whether and how individuals pay attention to gain- and loss-framed depression help-seeking messages-a mechanism that has significant implications for the strategic planning of health communication interventions. In order to enable the effective matching of message design and audience features, this study investigated attention patterns for gain (n = 75)- and loss (n = 78)-framed depression help-seeking messages using eye-tracking technology and self-report measures. The results confirmed that depression is a characteristic of risk avoidance and negative cognition. Depressed participants tended to pay more attention to disease information that was placed in a loss-framed rather than a gain-framed depression help-seeking message. Using negative message framing strategies for health messages seeking to educate about depression symptoms might therefore be a useful persuasive strategy-particularly when disseminated to vulnerable populations affected by depression. Furthermore, the present study emphasizes the effective use of eye-tracking technology in communication research.

Effects of argument quality, source credibility and self-reported diabetes knowledge on message attitudes: an experiment using diabetes related messages.

Science.gov (United States)

Lin, Tung-Cheng; Hwang, Lih-Lian; Lai, Yung-Jye

2017-05-17

Previous studies have reported that credibility and content (argument quality) are the most critical factors affecting the quality of health information and its acceptance and use; however, this causal relationship merits further investigation in the context of health education. Moreover, message recipients' prior knowledge may moderate these relationships. This study used the elaboration likelihood model to determine the main effects of argument quality, source credibility and the moderating effect of self-reported diabetes knowledge on message attitudes. A between-subjects experimental design using an educational message concerning diabetes for manipulation was applied to validate the effects empirically. A total of 181 participants without diabetes were recruited from the Department of Health, Taipei City Government. Four group messages were manipulated in terms of argument quality (high and low) × source credibility (high and low). Argument quality and source credibility of health information significantly influenced the attitude of message recipients. The participants with high self-reported knowledge participants exhibited significant disapproval for messages with low argument quality. Effective health information should provide objective descriptions and cite reliable sources; in addition, it should provide accurate, customised messages for recipients who have high background knowledge level and ability to discern message quality. © 2017 Health Libraries Group Health Information & Libraries Journal.

Synchronization in complex networks with switching topology

International Nuclear Information System (INIS)

Wang, Lei; Wang, Qing-guo

2011-01-01

This Letter investigates synchronization issues of complex dynamical networks with switching topology. By constructing a common Lyapunov function, we show that local and global synchronization for a linearly coupled network with switching topology can be evaluated by the time average of second smallest eigenvalues corresponding to the Laplacians of switching topology. This result is quite powerful and can be further used to explore various switching cases for complex dynamical networks. Numerical simulations illustrate the effectiveness of the obtained results in the end. -- Highlights: → Synchronization of complex networks with switching topology is investigated. → A common Lyapunov function is established for synchronization of switching network. → The common Lyapunov function is not necessary to monotonically decrease with time. → Synchronization is determined by the second smallest eigenvalue of its Laplacian. → Synchronization criterion can be used to investigate various switching cases.

Three types of generalized synchronization

Energy Technology Data Exchange (ETDEWEB)

Yang Junzhong [School of Science, Beijing University of Posts and Telecomunications, Beijing 100876 (China)]. E-mail: jzyang@bupt.edu.cn; Hu Gang [China Center for Advanced Science and Technology (CCAST) (World Laboratory), PO Box 8730, Beijing 100080 (China) and Department of Physics, Beijing Normal University, Beijing 100875 (China)]. E-mail: ganghu@bnu.edu.cn

2007-02-05

The roles played by drive and response systems on generalized chaos synchronization (GS) are studied. And the generalized synchronization is classified, based on these roles, to three distinctive types: the passive GS which is mainly determined by the response system and insensitive to the driving signal; the resonant GS where phase synchronization between the drive and response systems is preceding GS; and the interacting GS where both the drive and response have influences on the status of GS. The features of these GS types and the possible changes from one types to others are investigated.

Three types of generalized synchronization

International Nuclear Information System (INIS)

Yang Junzhong; Hu Gang

2007-01-01

The roles played by drive and response systems on generalized chaos synchronization (GS) are studied. And the generalized synchronization is classified, based on these roles, to three distinctive types: the passive GS which is mainly determined by the response system and insensitive to the driving signal; the resonant GS where phase synchronization between the drive and response systems is preceding GS; and the interacting GS where both the drive and response have influences on the status of GS. The features of these GS types and the possible changes from one types to others are investigated

Synchronous Half-Wave Rectifier

Science.gov (United States)

Rippel, Wally E.

1989-01-01

Synchronous rectifying circuit behaves like diode having unusually low voltage drop during forward-voltage half cycles. Circuit particularly useful in power supplies with potentials of 5 Vdc or less, where normal forward-voltage drops in ordinary diodes unacceptably large. Fabricated as monolithic assembly or as hybrid. Synchronous half-wave rectifier includes active circuits to attain low forward voltage drop and high rectification efficiency.

Introduction to media synchronization (Mediasync)

NARCIS (Netherlands)

M.A. Montagud Climent (Mario); P.S. Cesar Garcia (Pablo Santiago); F. Boronat (Fernando); A.J. Jansen (Jack)

2018-01-01

textabstractMedia synchronization is a core research area in multimedia systems. This chapter introduces the area by providing key definitions, classifications, and examples. It also discusses the relevance of different types of media synchronization to ensure satisfactory Quality of Experience

Quantum signature scheme for known quantum messages

International Nuclear Information System (INIS)

Kim, Taewan; Lee, Hyang-Sook

2015-01-01

When we want to sign a quantum message that we create, we can use arbitrated quantum signature schemes which are possible to sign for not only known quantum messages but also unknown quantum messages. However, since the arbitrated quantum signature schemes need the help of a trusted arbitrator in each verification of the signature, it is known that the schemes are not convenient in practical use. If we consider only known quantum messages such as the above situation, there can exist a quantum signature scheme with more efficient structure. In this paper, we present a new quantum signature scheme for known quantum messages without the help of an arbitrator. Differing from arbitrated quantum signature schemes based on the quantum one-time pad with the symmetric key, since our scheme is based on quantum public-key cryptosystems, the validity of the signature can be verified by a receiver without the help of an arbitrator. Moreover, we show that our scheme provides the functions of quantum message integrity, user authentication and non-repudiation of the origin as in digital signature schemes. (paper)

Instant Messaging by SIP

Science.gov (United States)

Muhi, Daniel; Dulai, Tibor; Jaskó, Szilárd

2008-11-01

SIP is a general-purpose application layer protocol which is able to establish sessions between two or more parties. These sessions are mainly telephone calls and multimedia conferences. However it can be used for other purposes like instant messaging and presence service. SIP has a very important role in mobile communication as more and more communicating applications are going mobile. In this paper we would like to show how SIP can be used for instant messaging purposes.

Robust synchronization of chaotic systems via feedback

Energy Technology Data Exchange (ETDEWEB)

Femat, Ricardo [IPICYT, San Luis Potosi (Mexico). Dept. de Matematicas Aplicadas; Solis-Perales, Gualberto [Universidad de Guadalajara, Centro Univ. de Ciencias Exactas e Ingenierias (Mexico). Div. de Electronica y Computacion

2008-07-01

This volume includes the results derived during last ten years about both suppression and synchronization of chaotic -continuous time- systems. Along this time, the concept was to study how the intrinsic properties of dynamical systems can be exploited to suppress and to synchronize the chaotic behaviour and what synchronization phenomena can be found under feedback interconnection. A compilation of these findings is described in this book. This book shows a perspective on synchronization of chaotic systems. (orig.)

The Message Logging System for NOνA Experiment

International Nuclear Information System (INIS)

Lu Qiming; Kowalkowski, J B; Biery, K A

2011-01-01

The message logging system provides the infrastructure for all of the distributed processes in the data acquisition (DAQ) to report status messages of various severities in a consistent manner to a central location, as well as providing the tools for displaying and archiving the messages. The message logging system has been developed over a decade, and has been run successfully on CDF and CMS experiments. The most recent work to the message logging system is to build it as a stand-alone package with the name MessageFacility which works for any generic framework or applications, with NOνA as the first driving user. System designs and architectures, as well as the efforts of making it a generic library will be discussed. We also present new features that have been added.

Synchronization of ;light-sensitive; Hindmarsh-Rose neurons

Science.gov (United States)

Castanedo-Guerra, Isaac; Steur, Erik; Nijmeijer, Henk

2018-04-01

The suprachiasmatic nucleus is a network of synchronized neurons whose electrical activity follows a 24 h cycle. The synchronization phenomenon (among these neurons) is not completely understood. In this work we study, via experiments and numerical simulations, the phenomenon in which the synchronization threshold changes under the influence of an external (bifurcation) parameter in coupled Hindmarsh-Rose neurons. This parameter ;shapes; the activity of the individual neurons the same way as some neurons in the brain react to light. We corroborate this experimental finding with numerical simulations by quantifying the amount of synchronization using Pearson's correlation coefficient. In order to address the local stability problem of the synchronous state, Floquet theory is applied in the case where the dynamic systems show continuous periodic solutions. These results show how the sufficient coupling strength for synchronization between these neurons is affected by an external cue (e.g. light).

Distributed Synchronization in Communication Networks

Science.gov (United States)

2018-01-24

synchronization. Secondly, it is known that identical oscillators with sin() coupling functions are guaranteed to synchronize in phase on a complete...provide sufficient conditions for phase- locking , i.e., convergence to a stable equilibrium almost surely. We additionally find conditions when the

Symbol Synchronization for Diffusion-Based Molecular Communications.

Science.gov (United States)

Jamali, Vahid; Ahmadzadeh, Arman; Schober, Robert

2017-12-01

Symbol synchronization refers to the estimation of the start of a symbol interval and is needed for reliable detection. In this paper, we develop several symbol synchronization schemes for molecular communication (MC) systems where we consider some practical challenges, which have not been addressed in the literature yet. In particular, we take into account that in MC systems, the transmitter may not be equipped with an internal clock and may not be able to emit molecules with a fixed release frequency. Such restrictions hold for practical nanotransmitters, e.g., modified cells, where the lengths of the symbol intervals may vary due to the inherent randomness in the availability of food and energy for molecule generation, the process for molecule production, and the release process. To address this issue, we develop two synchronization-detection frameworks which both employ two types of molecule. In the first framework, one type of molecule is used for symbol synchronization and the other one is used for data detection, whereas in the second framework, both types of molecule are used for joint symbol synchronization and data detection. For both frameworks, we first derive the optimal maximum likelihood (ML) symbol synchronization schemes as performance upper bounds. Since ML synchronization entails high complexity, for each framework, we also propose three low-complexity suboptimal schemes, namely a linear filter-based scheme, a peak observation-based scheme, and a threshold-trigger scheme, which are suitable for MC systems with limited computational capabilities. Furthermore, we study the relative complexity and the constraints associated with the proposed schemes and the impact of the insertion and deletion errors that arise due to imperfect synchronization. Our simulation results reveal the effectiveness of the proposed synchronization schemes and suggest that the end-to-end performance of MC systems significantly depends on the accuracy of the symbol

Gain versus loss-framed messaging and colorectal cancer screening among African Americans: A preliminary examination of perceived racism and culturally targeted dual messaging.

Science.gov (United States)

Lucas, Todd; Hayman, Lenwood W; Blessman, James E; Asabigi, Kanzoni; Novak, Julie M

2016-05-01

This preliminary study examined the effect of gain versus loss-framed messaging as well as culturally targeted personal prevention messaging on African Americans' receptivity to colorectal cancer (CRC) screening. This research also examined mechanistic functions of perceived racism in response to message framing. Community samples of African Americans (N = 132) and White Americans (N = 50) who were non-compliant with recommended CRC screening completed an online education module about CRC, and were either exposed to a gain-framed or loss-framed message about CRC screening. Half of African Americans were exposed to an additional and culturally targeted self-control message about personal prevention of CRC. Theory of planned behavior measures of attitudes, normative beliefs, perceived behavioural control, and intentions to obtain a CRC screen served as primary outcomes. The effect of messaging on perceived racism was also measured as an outcome. Consistent with prior research, White Americans were more receptive to CRC screening when exposed to a loss-framed message. However, African Americans were more receptive when exposed to a gain-framed message. The contrary effect of loss-framed messaging on receptivity to screening among African Americans was mediated by an increase in perceived racism. However, including an additional and culturally targeted prevention message mitigated the adverse effect of a loss-framed message. This study identifies an important potential cultural difference in the effect of message framing on illness screening among African Americans, while also suggesting a culturally relevant linking mechanism. This study also suggests the potential for simultaneously presented and culturally targeted messaging to alter the effects of gain and loss-framed messaging on African Americans. What is already known on this subject? African Americans are at an increased risk of both developing and dying from colorectal cancer (CRC). These disparities can be

Synchronization of coupled metronomes on two layers

Science.gov (United States)

Zhang, Jing; Yu, Yi-Zhen; Wang, Xin-Gang

2017-12-01

Coupled metronomes serve as a paradigmatic model for exploring the collective behaviors of complex dynamical systems, as well as a classical setup for classroom demonstrations of synchronization phenomena. Whereas previous studies of metronome synchronization have been concentrating on symmetric coupling schemes, here we consider the asymmetric case by adopting the scheme of layered metronomes. Specifically, we place two metronomes on each layer, and couple two layers by placing one on top of the other. By varying the initial conditions of the metronomes and adjusting the friction between the two layers, a variety of synchronous patterns are observed in experiment, including the splay synchronization (SS) state, the generalized splay synchronization (GSS) state, the anti-phase synchronization (APS) state, the in-phase delay synchronization (IPDS) state, and the in-phase synchronization (IPS) state. In particular, the IPDS state, in which the metronomes on each layer are synchronized in phase but are of a constant phase delay to metronomes on the other layer, is observed for the first time. In addition, a new technique based on audio signals is proposed for pattern detection, which is more convenient and easier to apply than the existing acquisition techniques. Furthermore, a theoretical model is developed to explain the experimental observations, and is employed to explore the dynamical properties of the patterns, including the basin distributions and the pattern transitions. Our study sheds new lights on the collective behaviors of coupled metronomes, and the developed setup can be used in the classroom for demonstration purposes.

Chaos synchronization based on intermittent state observer

Institute of Scientific and Technical Information of China (English)

Li Guo-Hui; Zhou Shi-Ping; Xu De-Ming

2004-01-01

This paper describes the method of synchronizing slave to the master trajectory using an intermittent state observer by constructing a synchronizer which drives the response system globally tracing the driving system asymptotically. It has been shown from the theory of synchronization error-analysis that a satisfactory result of chaos synchronization is expected under an appropriate intermittent period and state observer. Compared with continuous control method,the proposed intermittent method can target the desired orbit more efficiently. The application of the method is demonstrated on the hyperchaotic Rossler systems. Numerical simulations show that the length of the synchronization interval rs is of crucial importance for our scheme, and the method is robust with respect to parameter mismatch.

Synchronization of Coupled Neurons Controlled by a Pacemaker

International Nuclear Information System (INIS)

Li Mei-Sheng; Zhang Hong-Hui; Zhao Yong; Shi Xia

2011-01-01

We investigate synchronization of Hindmarsh—Rose neurons with gap junctions under the control of a pacemaker. In a ring Hindmarsh—Rose neuronal network, the coupled neurons with the pacemaker can occur in synchronization more easily than those without the pacemaker. Furthermore, the pacemaker can induce phase synchronization or nearly-complete synchronization of nonidentical neurons. This synchronization can occur more easily when time delay is considered. Theses results can be helpful to understand the activities of the real neuronal system. (general)

Small-world networks exhibit pronounced intermittent synchronization

Science.gov (United States)

Choudhary, Anshul; Mitra, Chiranjit; Kohar, Vivek; Sinha, Sudeshna; Kurths, Jürgen

2017-11-01

We report the phenomenon of temporally intermittently synchronized and desynchronized dynamics in Watts-Strogatz networks of chaotic Rössler oscillators. We consider topologies for which the master stability function (MSF) predicts stable synchronized behaviour, as the rewiring probability (p) is tuned from 0 to 1. MSF essentially utilizes the largest non-zero Lyapunov exponent transversal to the synchronization manifold in making stability considerations, thereby ignoring the other Lyapunov exponents. However, for an N-node networked dynamical system, we observe that the difference in its Lyapunov spectra (corresponding to the N - 1 directions transversal to the synchronization manifold) is crucial and serves as an indicator of the presence of intermittently synchronized behaviour. In addition to the linear stability-based (MSF) analysis, we further provide global stability estimate in terms of the fraction of state-space volume shared by the intermittently synchronized state, as p is varied from 0 to 1. This fraction becomes appreciably large in the small-world regime, which is surprising, since this limit has been otherwise considered optimal for synchronized dynamics. Finally, we characterize the nature of the observed intermittency and its dominance in state-space as network rewiring probability (p) is varied.

Global chaos synchronization with channel time-delay

International Nuclear Information System (INIS)

Jiang Guoping; Zheng Weixing; Chen Guanrong

2004-01-01

This paper addresses a practical issue in chaos synchronization where there is a time-delay in the receiver as compared with the transmitter. A new synchronization scheme and a general criterion for global chaos synchronization are proposed and developed from the approach of unidirectional linear error feedback coupling with time-delay. The chaotic Chua's circuit is used for illustration, where the coupling parameters are determined according to the criterion under which the global chaos synchronization of the time-delay coupled systems is achieved

Photoacoustic Soot Spectrometer (PASS) Instrument Handbook

Energy Technology Data Exchange (ETDEWEB)

Dubey, M [Los Alamos National Laboratory; Springston, S [Brookhaven National Laboratory; Koontz, A [Pacific Northwest National Laboratory; Aiken, A [Los Alamos National Laboratory

2013-01-17

The photoacoustic soot spectrometer (PASS) measures light absorption by aerosol particles. As the particles pass through a laser beam, the absorbed energy heats the particles and in turn the surrounding air, which sets off a pressure wave that can be detected by a microphone. The PASS instruments deployed by ARM can also simultaneously measure the scattered laser light at three wavelengths and therefore provide a direct measure of the single-scattering albedo. The Operator Manual for the PASS-3100 is included here with the permission of Droplet Measurement Technologies, the instrument’s manufacturer.

Effects of Text Messaging on Academic Performance

OpenAIRE

Barks Amanda; Searight H. Russell; Ratwik Susan

2011-01-01

University students frequently send and receive cellular phone text messages during classroominstruction. Cognitive psychology research indicates that multi-tasking is frequently associatedwith performance cost. However, university students often have considerable experience withelectronic multi-tasking and may believe that they can devote necessary attention to a classroomlecture while sending and receiving text messages. In the current study, university students whoused text messaging were ...

Reactions to threatening health messages.

Science.gov (United States)

Ten Hoor, Gill A; Peters, Gjalt-Jorn Y; Kalagi, Janice; de Groot, Lianne; Grootjans, Karlijne; Huschens, Alexander; Köhninger, Constanze; Kölgen, Lizan; Pelssers, Isabelle; Schütt, Toby; Thomas, Sophia; Ruiter, Robert A C; Kok, Gerjo

2012-11-21

Threatening health messages that focus on severity are popular, but frequently have no effect or even a counterproductive effect on behavior change. This paradox (i.e. wide application despite low effectiveness) may be partly explained by the intuitive appeal of threatening communication: it may be hard to predict the defensive reactions occurring in response to fear appeals. We examine this hypothesis by using two studies by Brown and colleagues, which provide evidence that threatening health messages in the form of distressing imagery in anti-smoking and anti-alcohol campaigns cause defensive reactions. We simulated both Brown et al. experiments, asking participants to estimate the reactions of the original study subjects to the threatening health information (n = 93). Afterwards, we presented the actual original study outcomes. One week later, we assessed whether this knowledge of the actual study outcomes helped participants to more successfully estimate the effectiveness of the threatening health information (n = 72). Results showed that participants were initially convinced of the effectiveness of threatening health messages and were unable to anticipate the defensive reactions that in fact occurred. Furthermore, these estimates did not improve after participants had been explained the dynamics of threatening communication as well as what the effects of the threatening communication had been in reality. These findings are consistent with the hypothesis that the effectiveness of threatening health messages is intuitively appealing. What is more, providing empirical evidence against the use of threatening health messages has very little effect on this intuitive appeal.

Instant messaging at the hospital: supporting articulation work?

Science.gov (United States)

Iversen, Tobias Buschmann; Melby, Line; Toussaint, Pieter

2013-09-01

Clinical work is increasingly fragmented and requires extensive articulation and coordination. Computer systems may support such work. In this study, we investigate how instant messaging functions as a tool for supporting articulation work at the hospital. This paper aims to describe the characteristics of instant messaging communication in terms of number and length of messages, distribution over time, and the number of participants included in conversations. We also aim to determine what kind of articulation work is supported by analysing message content. Analysis of one month's worth of instant messages sent through the perioperative coordination and communication system at a Danish hospital. Instant messaging was found to be used extensively for articulation work, mostly through short, simple conversational exchanges. It is used particularly often for communication concerning the patient, specifically, the coordination and logistics of patient care. Instant messaging is used by all actors involved in the perioperative domain. Articulation work and clinical work are hard to separate in a real clinical setting. Predefined messages and strict workflow design do not suffice when supporting communication in the context of collaborative clinical work. Flexibility is of vital importance, and this needs to be reflected in the design of supportive communication systems. Copyright © 2013 Elsevier Ireland Ltd. All rights reserved.

Global chaos synchronization of coupled parametrically excited ...

Indian Academy of Sciences (India)

In this paper, we study the synchronization behaviour of two linearly coupled parametrically excited chaotic pendula. The stability of the synchronized state is examined using Lyapunov stability theory and linear matrix inequality (LMI); and some sufficient criteria for global asymptotic synchronization are derived from which ...

Full state hybrid projective synchronization in hyperchaotic systems

International Nuclear Information System (INIS)

Chu Yandong; Chang Yingxiang; Zhang Jiangang; Li Xianfeng; An Xinlei

2009-01-01

In this letter, we investigate the full state hybrid projective synchronization (FSHPS) which includes complete synchronization, anti-synchronization and projective synchronization as its special items. Based on Lyapunov stability theory a controller can be designed for achieving the FSHPS of hyperchaotic systems. Numerical simulations are provided to verify the effectiveness of the proposed scheme.

Synchronizing noisy nonidentical oscillators by transient uncoupling

Energy Technology Data Exchange (ETDEWEB)

Tandon, Aditya, E-mail: adityat@iitk.ac.in; Mannattil, Manu, E-mail: mmanu@iitk.ac.in [Department of Physics, Indian Institute of Technology Kanpur, Kanpur, Uttar Pradesh 208016 (India); Schröder, Malte, E-mail: malte@nld.ds.mpg.de [Network Dynamics, Max Planck Institute for Dynamics and Self-Organization (MPIDS), 37077 Göttingen (Germany); Timme, Marc, E-mail: timme@nld.ds.mpg.de [Network Dynamics, Max Planck Institute for Dynamics and Self-Organization (MPIDS), 37077 Göttingen (Germany); Department of Physics, Technical University of Darmstadt, 64289 Darmstadt (Germany); Chakraborty, Sagar, E-mail: sagarc@iitk.ac.in [Department of Physics, Indian Institute of Technology Kanpur, Kanpur, Uttar Pradesh 208016 (India); Mechanics and Applied Mathematics Group, Indian Institute of Technology Kanpur, Kanpur, Uttar Pradesh 208016 (India)

2016-09-15

Synchronization is the process of achieving identical dynamics among coupled identical units. If the units are different from each other, their dynamics cannot become identical; yet, after transients, there may emerge a functional relationship between them—a phenomenon termed “generalized synchronization.” Here, we show that the concept of transient uncoupling, recently introduced for synchronizing identical units, also supports generalized synchronization among nonidentical chaotic units. Generalized synchronization can be achieved by transient uncoupling even when it is impossible by regular coupling. We furthermore demonstrate that transient uncoupling stabilizes synchronization in the presence of common noise. Transient uncoupling works best if the units stay uncoupled whenever the driven orbit visits regions that are locally diverging in its phase space. Thus, to select a favorable uncoupling region, we propose an intuitive method that measures the local divergence at the phase points of the driven unit's trajectory by linearizing the flow and subsequently suppresses the divergence by uncoupling.

Synchronization in complex networks with a modular structure.

Science.gov (United States)

Park, Kwangho; Lai, Ying-Cheng; Gupte, Saurabh; Kim, Jong-Won

2006-03-01

Networks with a community (or modular) structure arise in social and biological sciences. In such a network individuals tend to form local communities, each having dense internal connections. The linkage among the communities is, however, much more sparse. The dynamics on modular networks, for instance synchronization, may be of great social or biological interest. (Here by synchronization we mean some synchronous behavior among the nodes in the network, not, for example, partially synchronous behavior in the network or the synchronizability of the network with some external dynamics.) By using a recent theoretical framework, the master-stability approach originally introduced by Pecora and Carroll in the context of synchronization in coupled nonlinear oscillators, we address synchronization in complex modular networks. We use a prototype model and develop scaling relations for the network synchronizability with respect to variations of some key network structural parameters. Our results indicate that random, long-range links among distant modules is the key to synchronization. As an application we suggest a viable strategy to achieve synchronous behavior in social networks.

Outpatient blood pressure monitoring using bi-directional text messaging.

Science.gov (United States)

Anthony, Chris A; Polgreen, Linnea A; Chounramany, James; Foster, Eric D; Goerdt, Christopher J; Miller, Michelle L; Suneja, Manish; Segre, Alberto M; Carter, Barry L; Polgreen, Philip M

2015-05-01

To diagnose hypertension, multiple blood pressure (BP) measurements are recommended. We randomized patients into three groups: EMR-only (patients recorded BP measurements in an electronic medical record [EMR] web portal), EMR + reminders (patients were sent text message reminders to record their BP measurements in the EMR), and bi-directional text messaging (patients were sent a text message asking them to respond with their current BP). Subjects were asked to complete 14 measurements. Automated messages were sent to each patient in the bi-directional text messaging and EMR + reminder groups twice daily. Among 121 patients, those in the bi-directional text messaging group reported the full 14 measurements more often than both the EMR-only group (P text messaging is an effective way to gather patient BP data. Text-message-based reminders alone are an effective way to encourage patients to record BP measurements. Copyright © 2015 The Authors. Published by Elsevier Inc. All rights reserved.

Tracing How Normative Messages May Influence Physical Activity Intention.

Science.gov (United States)

van Bavel, René; Esposito, Gabriele; Baranowski, Tom; Duch-Brown, Néstor

2017-04-01

Normative messages have been shown to increase intention to do physical activity. We traced how "positive" and "negative" normative messages influenced physical activity intention by comparing constructs of the model of goal-directed behavior with descriptive norms (MGDB + DNs) across control and treatment groups in an experiment. For this purpose, 16-24-year-old respondents (n = 1,200) in Bulgaria, Croatia, and Romania were asked about their age, sex, and levels of physical activity before being exposed to positive and negative normative messages and completing a questionnaire with MGDB + DNs scales. Different MGDB + DNs constructs were influenced by the normative messages: compared with the control, the negative message group showed stronger attitudes (p = .003) and the positive message group showed higher positive anticipated emotions (p = .005). The positive message's effect is consistent with the literature on conformity to social norms. The negative message's effect lends itself to interpretations based on social identity and deviance regulation theories.

Effects of Instant Messaging on School Performance in Adolescents.

Science.gov (United States)

Grover, Karan; Pecor, Keith; Malkowski, Michael; Kang, Lilia; Machado, Sasha; Lulla, Roshni; Heisey, David; Ming, Xue

2016-06-01

Instant messaging may compromise sleep quality and school performance in adolescents. We aimed to determine associations between nighttime messaging and daytime sleepiness, self-reported sleep parameters, and/or school performance. Students from 3 high schools in New Jersey completed anonymous questionnaires assessing sleep duration, daytime sleepiness, messaging habits, and academic performance. Of the 2,352 students sampled, 1,537 responses were contrasted among grades, sexes, and messaging duration, both before and after lights out. Students who reported longer duration of messaging after lights out were more likely to report a shorter sleep duration, higher rate of daytime sleepiness, and poorer academic performance. Messaging before lights out was not associated with higher rates of daytime sleepiness or poorer academic performance. Females reported more messaging, more daytime sleepiness, and better academic performance than males. There may be an association between text messaging and school performance in this cohort of students. © The Author(s) 2016.

Business cycle synchronization in Europe

DEFF Research Database (Denmark)

Bergman, Ulf Michael; Jonung, Lars

2011-01-01

In this paper we study business cycle synchronization in the three Scandinavian countries Denmark, Norway and Sweden prior to, during and after the Scandinavian Currency Union 1873–1913. We find that the degree of synchronization tended to increase during the currency union, thus supporting earlier...

Digital synchronization and communication techniques

Science.gov (United States)

Lindsey, William C.

1992-01-01

Information on digital synchronization and communication techniques is given in viewgraph form. Topics covered include phase shift keying, modems, characteristics of open loop digital synchronizers, an open loop phase and frequency estimator, and a digital receiver structure using an open loop estimator in a decision directed architecture.

Nonlinear observer based phase synchronization of chaotic systems

International Nuclear Information System (INIS)

Meng Juan; Wang Xingyuan

2007-01-01

This Letter analyzes the phase synchronization problem of autonomous chaotic systems. Based on the nonlinear state observer algorithm and the pole placement technique, a phase synchronization scheme is designed. The phase synchronization of a new chaotic system is achieved by using this observer controller. Numerical simulations further demonstrate the effectiveness of the proposed phase synchronization scheme

Structural damage detection robust against time synchronization errors

International Nuclear Information System (INIS)

Yan, Guirong; Dyke, Shirley J

2010-01-01

Structural damage detection based on wireless sensor networks can be affected significantly by time synchronization errors among sensors. Precise time synchronization of sensor nodes has been viewed as crucial for addressing this issue. However, precise time synchronization over a long period of time is often impractical in large wireless sensor networks due to two inherent challenges. First, time synchronization needs to be performed periodically, requiring frequent wireless communication among sensors at significant energy cost. Second, significant time synchronization errors may result from node failures which are likely to occur during long-term deployment over civil infrastructures. In this paper, a damage detection approach is proposed that is robust against time synchronization errors in wireless sensor networks. The paper first examines the ways in which time synchronization errors distort identified mode shapes, and then proposes a strategy for reducing distortion in the identified mode shapes. Modified values for these identified mode shapes are then used in conjunction with flexibility-based damage detection methods to localize damage. This alternative approach relaxes the need for frequent sensor synchronization and can tolerate significant time synchronization errors caused by node failures. The proposed approach is successfully demonstrated through numerical simulations and experimental tests in a lab

Pilotless Frame Synchronization Using LDPC Code Constraints

Science.gov (United States)

Jones, Christopher; Vissasenor, John

2009-01-01

A method of pilotless frame synchronization has been devised for low- density parity-check (LDPC) codes. In pilotless frame synchronization , there are no pilot symbols; instead, the offset is estimated by ex ploiting selected aspects of the structure of the code. The advantag e of pilotless frame synchronization is that the bandwidth of the sig nal is reduced by an amount associated with elimination of the pilot symbols. The disadvantage is an increase in the amount of receiver data processing needed for frame synchronization.

Acoustophoretic Synchronization of Mammalian Cells in Microchannels

DEFF Research Database (Denmark)

Thévoz, P.; Adams, J.D.; Shea, H.

2010-01-01

We report the first use of ultrasonic standing waves to achieve cell cycle phase synchronization in mammalian cells in a high-throughput and reagent-free manner. The acoustophoretic cell synchronization (ACS) device utilizes volume-dependent acoustic radiation force within a microchannel to selec......We report the first use of ultrasonic standing waves to achieve cell cycle phase synchronization in mammalian cells in a high-throughput and reagent-free manner. The acoustophoretic cell synchronization (ACS) device utilizes volume-dependent acoustic radiation force within a microchannel...

The WLCG Messaging Service and its Future

CERN Document Server

Cons, Lionel

2012-01-01

Enterprise messaging is seen as an attractive mechanism to simplify and extend several portions of the Grid middleware, from low level monitoring to experiments dashboards. The production messaging service currently used by WLCG includes four tightly coupled brokers operated by EGI (running Apache ActiveMQ and designed to host the Grid operational tools such as SAM) as well as two dedicated services for ATLAS-DDM and experiments dashboards (currently also running Apache ActiveMQ). In the future, this service is expected to grow in numbers of applications supported, brokers and technologies. The WLCG Messaging Roadmap identified three areas with room for improvement (security, scalability and availability/reliability) as well as ten practical recommendations to address them. This paper describes a messaging service architecture that is in line with these recommendations as well as a software architecture based on reusable components that ease interactions with the messaging service. These two architectures wil...

Adaptive Synchronization of Robotic Sensor Networks

OpenAIRE

Yıldırım, Kasım Sinan; Gürcan, Önder

2014-01-01

The main focus of recent time synchronization research is developing power-efficient synchronization methods that meet pre-defined accuracy requirements. However, an aspect that has been often overlooked is the high dynamics of the network topology due to the mobility of the nodes. Employing existing flooding-based and peer-to-peer synchronization methods, are networked robots still be able to adapt themselves and self-adjust their logical clocks under mobile network dynamics? In this paper, ...

Pilot study of psychotherapeutic text messaging for depression.

Science.gov (United States)

Pfeiffer, Paul N; Henry, Jennifer; Ganoczy, Dara; Piette, John D

2017-08-01

Background Text messaging services could increase access to psychotherapeutic content for individuals with depression by avoiding barriers to in-person psychotherapy such as cost, transportation, and therapist availability. Determining whether text messages reflecting different psychotherapeutic techniques exhibit differences in acceptability or effectiveness may help guide service development. Objectives We aimed to determine: (1) the feasibility of delivering a psychotherapy-based text messaging service to people with depression identified via the internet, (2) whether there is variation in satisfaction with messages according to the type of psychotherapeutic technique they represent, and (3) whether symptoms of depression vary according to receipt of each message type and participants' satisfaction with the messages they received. Methods For this study 190 US adults who screened positive for a major depressive episode (Patient Health Questionnaire (PHQ-9) score ≥10) were recruited from online advertisements. Participants received a daily psychotherapy-based text message 6 days per week for 12 weeks. Text messages were developed by a team of psychiatrists, psychologists, and social workers to reflect three psychotherapeutic approaches: acceptance and commitment therapy (ACT), behavioural activation, and cognitive restructuring. Each week the message type for the week was randomly assigned from one of the three types, allowing for repeats. Participants were asked daily to rate each message. On the 7th day of each week, participants completed a two-item depression screener (PHQ-2). Web-based surveys at baseline, 6, and 12 weeks were used as the primary measure of depressive symptoms (PHQ-9). Results Of the 190 participants enrolled, 85 (45%) completed the 6-week web survey and 67 (35%) completed the 12-week survey. The mean baseline PHQ-9 score was 19.4 (SD 4.2) and there was a statistically significant mean improvement in PHQ-9 scores of -2.9 (SD 6.0; p�

Cooperative Localization for Mobile Networks

DEFF Research Database (Denmark)

Cakmak, Burak; Urup, Daniel Nygaard; Meyer, Florian

2016-01-01

We propose a hybrid message passing method for distributed cooperative localization and tracking of mobile agents. Belief propagation and mean field message passing are employed for, respectively, the motion-related and measurementrelated part of the factor graph. Using a Gaussian belief approxim......We propose a hybrid message passing method for distributed cooperative localization and tracking of mobile agents. Belief propagation and mean field message passing are employed for, respectively, the motion-related and measurementrelated part of the factor graph. Using a Gaussian belief...

Systematic and heuristic processing of majority and minority-endorsed messages: the effects of varying outcome relevance and levels of orientation on attitude and message processing.

Science.gov (United States)

Martin, Robin; Hewstone, Miles; Martin, Pearl Y

2007-01-01

Two experiments investigated the conditions under which majority and minority sources instigate systematic processing of their messages. Both experiments crossed source status (majority vs. minority) with message quality (strong vs. weak arguments). In each experiment, message elaboration was manipulated by varying either motivational (outcome relevance, Experiment 1) or cognitive (orientating tasks, Experiment 2) factors. The results showed that when either motivational or cognitive factors encouraged low message elaboration, there was heuristic acceptance of the majority position without detailed message processing. When the level of message elaboration was intermediate, there was message processing only for the minority source. Finally, when message elaboration was high, there was message processing for both source conditions. These results show that majority and minority influence is sensitive to motivational and cognitive factors that constrain or enhance message elaboration and that both sources can lead to systematic processing under specific circumstances.

Flow of emotional messages in artificial social networks

OpenAIRE

Chmiel, Anna; Holyst, Janusz A.

2010-01-01

Models of message flows in an artificial group of users communicating via the Internet are introduced and investigated using numerical simulations. We assumed that messages possess an emotional character with a positive valence and that the willingness to send the next affective message to a given person increases with the number of messages received from this person. As a result, the weights of links between group members evolve over time. Memory effects are introduced, taking into account t...

Synchronization and sequencing of data acquisition and control electronics at the European X-ray free electron laser

International Nuclear Information System (INIS)

Gessler, Patrick

2015-11-01

The 3.5 km long European X-Ray Free Electron Laser, currently under construction in northern Germany, will deliver bursts of up to 2700 short X-ray pulses every 100 ms, providing wavelengths between 0.05 and 6 nm, and a repetition rate of 4.5 MHz to several experiment stations. It allows in-depth research in various scientific fields. In order to set-up the beam, position samples and capture the measured variables, information from the accelerator, diagnostic devices and detectors have to be digitized, converted, processed, transferred, concentrated, distributed, reorganized, controlled and saved. All these steps have to be accurately synchronized and sequenced relative to the actual electron bunch or photon pulse in order to guarantee correct data acquisition timings and unique identification of each bunch passing the beamlines. This document provides a complete description of the planning, design, realization and evaluation of the European XFEL Timing System, which implements the synchronization and sequencing of the data acquisition and control electronics for the European X-Ray Free-Electron Laser Facility.

Understanding health food messages on Twitter for health literacy promotion.

Science.gov (United States)

Zhou, J; Liu, F; Zhou, H

2018-05-01

With the popularity of social media, Twitter has become an important tool to promote health literacy. However, many health-related messages on Twitter are dead-ended and cannot reach many people. This is unhelpful for health literacy promotion. This article aims to examine the features of online health food messages that people like to retweet. We adopted rumour theory as our theoretical foundation and extracted seven characteristics (i.e. emotional valence, attractiveness, sender's authoritativeness, external evidence, argument length, hashtags, and direct messages). A total of 10,025 health-related messages on Twitter were collected, and 1496 messages were randomly selected for further analysis. Each message was treated as one unit and then coded. All the hypotheses were tested with logistic regression. Emotional valence, attractiveness, sender's authoritativeness, argument length, and direct messages in a Twitter message had positive effects on people's retweet behaviour. The effect of external evidence was negative. Hashtags had no significant effect after consideration of other variables. Online health food messages containing positive emotions, including pictures, containing direct messages, having an authoritative sender, having longer arguments, or not containing external URLs are more likely to be retweeted. However, a message only containing positive or negative emotions or including direct messages without any support information will not be retweeted.

Perfect synchronization in networks of phase-frustrated oscillators

Science.gov (United States)

Kundu, Prosenjit; Hens, Chittaranjan; Barzel, Baruch; Pal, Pinaki

2017-11-01

Synchronizing phase-frustrated Kuramoto oscillators, a challenge that has found applications from neuronal networks to the power grid, is an eluding problem, as even small phase lags cause the oscillators to avoid synchronization. Here we show, constructively, how to strategically select the optimal frequency set, capturing the natural frequencies of all oscillators, for a given network and phase lags, that will ensure perfect synchronization. We find that high levels of synchronization are sustained in the vicinity of the optimal set, allowing for some level of deviation in the frequencies without significant degradation of synchronization. Demonstrating our results on first- and second-order phase-frustrated Kuramoto dynamics, we implement them on both model and real power grid networks, showing how to achieve synchronization in a phase-frustrated environment.

Synchronization Analysis of the Supermarket Refrigeration System

DEFF Research Database (Denmark)

Wisniewski, Rafal; Chen, Liang; Larsen, Lars Finn Sloth

2009-01-01

is analyzed using the bifurcation and chaos theory. It is demonstrated that the system can have a complex chaotic behavior, which is far from the synchronization. This shows that making the system chaotic is a good choice for a de-synchronization strategy. The positive maximum Lyapunov exponent is usually...... taken as an indication of the existence of chaos. It is used in the paper as a measure of performance for the tendency of the system to synchronize, that is, the higher value of the maximum Lyapunov exponent the lower risk for synchronization....

Price synchronization in retailing: some empirical evidence

Directory of Open Access Journals (Sweden)

Marcelo Resende

2014-06-01

Full Text Available The paper investigates the synchronization of price changes in the context of retail tire dealers in São Paulo-Brazil and selected items in supermarkets for cleaning supplies and food in Rio de Janeiro-Brazil. Results indicate similar and non-negligible synchronization for different brands, although magnitudes are distant from a perfect synchronization pattern. We find interesting patterns in inter-firm competition, with similar magnitudes across different tire types. Intra-chain synchronization is substantial, indicating that a common price adjustment policy tends to be sustained for each chain across different products.

78 FR 64202 - Quantitative Messaging Research

Science.gov (United States)

2013-10-28

... COMMODITY FUTURES TRADING COMMISSION Quantitative Messaging Research AGENCY: Commodity Futures... survey will follow qualitative message testing research (for which CFTC received fast- track OMB approval... comments. Please submit your comments using only one method and identify that it is for the ``Quantitative...

Synchronization of Estrus in Cattle: A Review

Directory of Open Access Journals (Sweden)

R. Islam

2011-06-01

Full Text Available Numbers of estrus synchronization programmes are available in cattle based on the use of various hormones like progesterone, prostaglandin F2a and their various combinations with other hormones like estrogen and Gonadotrophin Releasing hormone (GnRH. Selection of appropriate estrus synchronization protocol should be made on the basis of management capabilities and expectations of the farmer. Synchronization of oestrus can be accomplished with the injection of prostaglandin F2a alone, but it needs proper detection of the ovarian status of the cows as prostaglandin F2a is active in only functional corpus luteum in between 8 to 17 days of estrous cycle. Progesterone may reduce fertility up to 14 percent, but short time progesterone exposure (less than 14 days is beneficial. Addition of GnRH in the Progesterone or Prostaglandin based synchronization programme is helpful for more synchrony in estrus as GnRH may be helpful to synchronize the oestrous cycle in delayed pubertal heifers and post partum cows (Post partum anoestrum and further a single, timed artificial insemination is possible with this method. New methods of synchronizing estrus in which the GnRH-PG protocol is preceded by progesterone treatment offer effective synchronization of estrus with high fertility. [Vet. World 2011; 4(3.000: 136-141

Synchronization of coupled nonidentical multidelay feedback systems

International Nuclear Information System (INIS)

Hoang, Thang Manh; Nakagawa, Masahiro

2007-01-01

We present the lag synchronization of coupled nonidentical multidelay feedback systems, in which the synchronization signal is the sum of nonlinearly transformed components of delayed state variable. The sufficient condition for synchronization is considered by the Krasovskii-Lyapunov theory. The specific examples will demonstrate and verify the effectiveness of the proposed model

The Prodiguer Messaging Platform

Science.gov (United States)

Denvil, S.; Greenslade, M. A.; Carenton, N.; Levavasseur, G.; Raciazek, J.

2015-12-01

CONVERGENCE is a French multi-partner national project designed to gather HPC and informatics expertise to innovate in the context of running French global climate models with differing grids and at differing resolutions. Efficient and reliable execution of these models and the management and dissemination of model output are some of the complexities that CONVERGENCE aims to resolve.At any one moment in time, researchers affiliated with the Institut Pierre Simon Laplace (IPSL) climate modeling group, are running hundreds of global climate simulations. These simulations execute upon a heterogeneous set of French High Performance Computing (HPC) environments. The IPSL's simulation execution runtime libIGCM (library for IPSL Global Climate Modeling group) has recently been enhanced so as to support hitherto impossible realtime use cases such as simulation monitoring, data publication, metrics collection, simulation control, visualizations … etc. At the core of this enhancement is Prodiguer: an AMQP (Advanced Message Queue Protocol) based event driven asynchronous distributed messaging platform. libIGCM now dispatches copious amounts of information, in the form of messages, to the platform for remote processing by Prodiguer software agents at IPSL servers in Paris. Such processing takes several forms: Persisting message content to database(s); Launching rollback jobs upon simulation failure; Notifying downstream applications; Automation of visualization pipelines; We will describe and/or demonstrate the platform's: Technical implementation; Inherent ease of scalability; Inherent adaptiveness in respect to supervising simulations; Web portal receiving simulation notifications in realtime.

Fitness for synchronization of network motifs

DEFF Research Database (Denmark)

Vega, Y.M.; Vázquez-Prada, M.; Pacheco, A.F.

2004-01-01

We study the synchronization of Kuramoto's oscillators in small parts of networks known as motifs. We first report on the system dynamics for the case of a scale-free network and show the existence of a non-trivial critical point. We compute the probability that network motifs synchronize, and fi...... that the fitness for synchronization correlates well with motifs interconnectedness and structural complexity. Possible implications for present debates about network evolution in biological and other systems are discussed....

Impulsive synchronization of Chen's hyperchaotic system

International Nuclear Information System (INIS)

Haeri, Mohammad; Dehghani, Mahsa

2006-01-01

In this Letter the impulsive synchronization of the Chen's hyperchaotic systems is discussed. Some new and sufficient conditions on varying impulsive distance are established in order to guarantee the synchronizabillity of the systems using the synchronization method. In particular, some simple conditions are derived in synchronizing the systems by equal impulsive distances. Two illustrative examples are provided to show the feasibility and the effectiveness of the proposed method. The boundaries of the stable regions are also estimated

A True Open-Loop Synchronization Technique

DEFF Research Database (Denmark)

Golestan, Saeed; Vidal, Ana; Yepes, Alejandro G.

2016-01-01

Synchronization techniques can be broadly classified into two major categories: Closed-loop and open-loop methods. The open-loop synchronization (OLS) techniques, contrary to the closed-loop ones, are unconditionally stable and benefit from a fast dynamic response. Their performance, however, tends...... is to develop a true OLS (and therefore, unconditionally stable) technique without any need for the calculation of sine and cosine functions. The effectiveness of the proposed synchronization technique is confirmed through the simulation and experimental results....

Hybrid programming model for implicit PDE simulations on multicore architectures

KAUST Repository

Kaushik, Dinesh; Keyes, David E.; Balay, Satish; Smith, Barry F.

2011-01-01

The complexity of programming modern multicore processor based clusters is rapidly rising, with GPUs adding further demand for fine-grained parallelism. This paper analyzes the performance of the hybrid (MPI+OpenMP) programming model in the context of an implicit unstructured mesh CFD code. At the implementation level, the effects of cache locality, update management, work division, and synchronization frequency are studied. The hybrid model presents interesting algorithmic opportunities as well: the convergence of linear system solver is quicker than the pure MPI case since the parallel preconditioner stays stronger when hybrid model is used. This implies significant savings in the cost of communication and synchronization (explicit and implicit). Even though OpenMP based parallelism is easier to implement (with in a subdomain assigned to one MPI process for simplicity), getting good performance needs attention to data partitioning issues similar to those in the message-passing case. © 2011 Springer-Verlag.

Flagellar Synchronization Is a Simple Alternative to Cell Cycle Synchronization for Ciliary and Flagellar Studies.

Science.gov (United States)

Dutta, Soumita; Avasthi, Prachee

2017-01-01

The unicellular green alga Chlamydomonas reinhardtii is an ideal model organism for studies of ciliary function and assembly. In assays for biological and biochemical effects of various factors on flagellar structure and function, synchronous culture is advantageous for minimizing variability. Here, we have characterized a method in which 100% synchronization is achieved with respect to flagellar length but not with respect to the cell cycle. The method requires inducing flagellar regeneration by amputation of the entire cell population and limiting regeneration time. This results in a maximally homogeneous distribution of flagellar lengths at 3 h postamputation. We found that time-limiting new protein synthesis during flagellar synchronization limits variability in the unassembled pool of limiting flagellar protein and variability in flagellar length without affecting the range of cell volumes. We also found that long- and short-flagella mutants that regenerate normally require longer and shorter synchronization times, respectively. By minimizing flagellar length variability using a simple method requiring only hours and no changes in media, flagellar synchronization facilitates the detection of small changes in flagellar length resulting from both chemical and genetic perturbations in Chlamydomonas . This method increases our ability to probe the basic biology of ciliary size regulation and related disease etiologies. IMPORTANCE Cilia and flagella are highly conserved antenna-like organelles that found in nearly all mammalian cell types. They perform sensory and motile functions contributing to numerous physiological and developmental processes. Defects in their assembly and function are implicated in a wide range of human diseases ranging from retinal degeneration to cancer. Chlamydomonas reinhardtii is an algal model system for studying mammalian cilium formation and function. Here, we report a simple synchronization method that allows detection of small

Safety message broadcast in vehicular networks

CERN Document Server

Bi, Yuanguo; Zhuang, Weihua; Zhao, Hai

2017-01-01

This book presents the current research on safety message dissemination in vehicular networks, covering medium access control and relay selection for multi-hop safety message broadcast. Along with an overall overview of the architecture, characteristics, and applications of vehicular networks, the authors discuss the challenging issues in the research on performance improvement for safety applications, and provide a comprehensive review of the research literature. A cross layer broadcast protocol is included to support efficient safety message broadcast by jointly considering geographical location, physical-layer channel condition, and moving velocity of vehicles in the highway scenario. To further support multi-hop safety message broadcast in a complex road layout, the authors propose an urban multi-hop broadcast protocol that utilizes a novel forwarding node selection scheme. Additionally, a busy tone based medium access control scheme is designed to provide strict priority to safety applications in vehicle...

Synchronization of delay-coupled nonlinear oscillators: an approach based on the stability analysis of synchronized equilibria.

Science.gov (United States)

Michiels, Wim; Nijmeijer, Henk

2009-09-01

We consider the synchronization problem of an arbitrary number of coupled nonlinear oscillators with delays in the interconnections. The network topology is described by a directed graph. Unlike the conventional approach of deriving directly sufficient synchronization conditions, the approach of the paper starts from an exact stability analysis in a (gain, delay) parameter space of a synchronized equilibrium and extracts insights from an analysis of its bifurcations and from the corresponding emerging behavior. Instrumental to this analysis a factorization of the characteristic equation is employed that not only facilitates the analysis and reduces computational cost but also allows to determine the precise role of the individual agents and the topology of the network in the (in)stability mechanisms. The study provides an algorithm to perform a stability and bifurcation analysis of synchronized equilibria. Furthermore, it reveals fundamental limitations to synchronization and it explains under which conditions on the topology of the network and on the characteristics of the coupling the systems are expected to synchronize. In the second part of the paper the results are applied to coupled Lorenz systems. The main results show that for sufficiently large coupling gains, delay-coupled Lorenz systems exhibit a generic behavior that does not depend on the number of systems and the topology of the network, as long as some basic assumptions are satisfied, including the strong connectivity of the graph. Here the linearized stability analysis is strengthened by a nonlinear stability analysis which confirms the predictions based on the linearized stability and bifurcation analysis. This illustrates the usefulness of the exact linearized analysis in a situation where a direct nonlinear stability analysis is not possible or where it yields conservative conditions from which it is hard to get qualitative insights in the synchronization mechanisms and their scaling properties

Effects of Electronic Word - of - Mouth Messages

Directory of Open Access Journals (Sweden)

Choong Hoon Lim

2012-01-01

Full Text Available With the increased usage of online technologies, there has been an escalation of Electronic Word - of –Mouth (eWOM messages related to sport products and services offered and consumed. Therefore, in this original investigation by applying eWOM to the sport industry, this study examined how the combination of the quality of the eWOM message and the provider of the eWOM message affects purchaseintentions depending on the expertise level of the consumer. This study – which involved the collection of data from 134 students at a large university situated in the Midwest of the United States – utilized repeated measures of Analysis of Variance (ANOVA with tripartite groups of expertise and experimental conditions as independent variables. Purchase intention was the dependent variables. The results indicated that the quality of the eWOM message moderated the effect of the provider of the eWOM message. The subject’s level of expertise also had a moderating role on purchase intention.

Synchronization in networks with heterogeneous coupling delays

Science.gov (United States)

Otto, Andreas; Radons, Günter; Bachrathy, Dániel; Orosz, Gábor

2018-01-01

Synchronization in networks of identical oscillators with heterogeneous coupling delays is studied. A decomposition of the network dynamics is obtained by block diagonalizing a newly introduced adjacency lag operator which contains the topology of the network as well as the corresponding coupling delays. This generalizes the master stability function approach, which was developed for homogenous delays. As a result the network dynamics can be analyzed by delay differential equations with distributed delay, where different delay distributions emerge for different network modes. Frequency domain methods are used for the stability analysis of synchronized equilibria and synchronized periodic orbits. As an example, the synchronization behavior in a system of delay-coupled Hodgkin-Huxley neurons is investigated. It is shown that the parameter regions where synchronized periodic spiking is unstable expand when increasing the delay heterogeneity.

Individual differences in drivers' cognitive processing of road safety messages.

Science.gov (United States)

Kaye, Sherrie-Anne; White, Melanie J; Lewis, Ioni M

2013-01-01

Using Gray and McNaughton's (2000) revised reinforcement sensitivity theory (r-RST), we examined the influence of personality on processing of words presented in gain-framed and loss-framed anti-speeding messages and how the processing biases associated with personality influenced message acceptance. The r-RST predicts that the nervous system regulates personality and that behaviour is dependent upon the activation of the behavioural activation system (BAS), activated by reward cues and the fight-flight-freeze system (FFFS), activated by punishment cues. According to r-RST, individuals differ in the sensitivities of their BAS and FFFS (i.e., weak to strong), which in turn leads to stable patterns of behaviour in the presence of rewards and punishments, respectively. It was hypothesised that individual differences in personality (i.e., strength of the BAS and the FFFS) would influence the degree of both message processing (as measured by reaction time to previously viewed message words) and message acceptance (measured three ways by perceived message effectiveness, behavioural intentions, and attitudes). Specifically, it was anticipated that, individuals with a stronger BAS would process the words presented in the gain-frame messages faster than those with a weaker BAS and individuals with a stronger FFFS would process the words presented in the loss-frame messages faster than those with a weaker FFFS. Further, it was expected that greater processing (faster reaction times) would be associated with greater acceptance for that message. Driver licence holding students (N=108) were recruited to view one of four anti-speeding messages (i.e., social gain-frame, social loss-frame, physical gain-frame, and physical loss-frame). A computerised lexical decision task assessed participants' subsequent reaction times to message words, as an indicator of the extent of processing of the previously viewed message. Self-report measures assessed personality and the three message

Synchronization of hyperchaotic oscillators via single unidirectional chaotic-coupling

International Nuclear Information System (INIS)

Zou Yanli; Zhu Jie; Chen Guanrong; Luo Xiaoshu

2005-01-01

In this paper, synchronization of two hyperchaotic oscillators via a single variable's unidirectional coupling is studied. First, the synchronizability of the coupled hyperchaotic oscillators is proved mathematically. Then, the convergence speed of this synchronization scheme is analyzed. In order to speed up the response with a relatively large coupling strength, two kinds of chaotic coupling synchronization schemes are proposed. In terms of numerical simulations and the numerical calculation of the largest conditional Lyapunov exponent, it is shown that in a given range of coupling strengths, chaotic-coupling synchronization is quicker than the typical continuous-coupling synchronization. Furthermore, A circuit realization based on the chaotic synchronization scheme is designed and Pspice circuit simulation validates the simulated hyperchaos synchronization mechanism

Reactions to threatening health messages

Directory of Open Access Journals (Sweden)

ten Hoor Gill A

2012-11-01

Full Text Available Abstract Background Threatening health messages that focus on severity are popular, but frequently have no effect or even a counterproductive effect on behavior change. This paradox (i.e. wide application despite low effectiveness may be partly explained by the intuitive appeal of threatening communication: it may be hard to predict the defensive reactions occurring in response to fear appeals. We examine this hypothesis by using two studies by Brown and colleagues, which provide evidence that threatening health messages in the form of distressing imagery in anti-smoking and anti-alcohol campaigns cause defensive reactions. Methods We simulated both Brown et al. experiments, asking participants to estimate the reactions of the original study subjects to the threatening health information (n = 93. Afterwards, we presented the actual original study outcomes. One week later, we assessed whether this knowledge of the actual study outcomes helped participants to more successfully estimate the effectiveness of the threatening health information (n = 72. Results Results showed that participants were initially convinced of the effectiveness of threatening health messages and were unable to anticipate the defensive reactions that in fact occurred. Furthermore, these estimates did not improve after participants had been explained the dynamics of threatening communication as well as what the effects of the threatening communication had been in reality. Conclusions These findings are consistent with the hypothesis that the effectiveness of threatening health messages is intuitively appealing. What is more, providing empirical evidence against the use of threatening health messages has very little effect on this intuitive appeal.

Two novel synchronization criterions for a unified chaotic system

International Nuclear Information System (INIS)

Tao Chaohai; Xiong Hongxia; Hu Feng

2006-01-01

Two novel synchronization criterions are proposed in this paper. It includes drive-response synchronization and adaptive synchronization schemes. Moreover, these synchronization criterions can be applied to a large class of chaotic systems and are very useful for secure communication

Optimal operating conditions for external cavity semiconductor laser optical chaos communication system

International Nuclear Information System (INIS)

Priyadarshi, S; Pierce, I; Hong, Y; Shore, K A

2012-01-01

In optical chaos communications a message is masked in the noise-like broadband output of a chaotic transmitter laser, and message recovery is enabled through the synchronization of the transmitter and the (chaotic) receiver laser. Key issues are to identify the laser operating conditions which provide the highest quality synchronization conditions and those which provide optimized message extraction. In general such operating conditions are not coincident. In this paper numerical simulations are performed with the aim of identifying a regime of operation where the highest quality synchronization and optimizing message extraction efficiency are achieved simultaneously. Use of such an operating regime will facilitate practical deployment of optical chaos communications systems without the need for re-adjustment of laser operating conditions in the field. (paper)

Lol: New Language and Spelling in Instant Messaging

Science.gov (United States)

Varnhagen, Connie K.; McFall, G. Peggy; Pugh, Nicole; Routledge, Lisa; Sumida-MacDonald, Heather; Kwong, Trudy E.

2010-01-01

Written communication in instant messaging, text messaging, chat, and other forms of electronic communication appears to have generated a "new language" of abbreviations, acronyms, word combinations, and punctuation. In this naturalistic study, adolescents collected their instant messaging conversations for a 1-week period and then completed a…

Synchronization of Rikitake chaotic attractor using active control

International Nuclear Information System (INIS)

Vincent, U.E.

2005-01-01

Using synchronization technique based on control theory, we design an active controller which enables the synchronization of two identical Rikitake two-disc dynamo systems. Numerical simulations are used to show the robustness of the active control scheme in synchronizing coupled Rikitake dynamical systems. On the sequential application of the active control, transitions from temporary phase locking (TPL) state to complete synchronization state were found

A Novel Message Scheduling Framework for Delay Tolerant Networks Routing

KAUST Repository

Elwhishi, Ahmed

2013-05-01

Multicopy routing strategies have been considered the most applicable approaches to achieve message delivery in Delay Tolerant Networks (DTNs). Epidemic routing and two-hop forwarding routing are two well-reported approaches for delay tolerant networks routing which allow multiple message replicas to be launched in order to increase message delivery ratio and/or reduce message delivery delay. This advantage, nonetheless, is at the expense of additional buffer space and bandwidth overhead. Thus, to achieve efficient utilization of network resources, it is important to come up with an effective message scheduling strategy to determine which messages should be forwarded and which should be dropped in case of buffer is full. This paper investigates a new message scheduling framework for epidemic and two-hop forwarding routing in DTNs, such that the forwarding/dropping decision can be made at a node during each contact for either optimal message delivery ratio or message delivery delay. Extensive simulation results show that the proposed message scheduling framework can achieve better performance than its counterparts.

Robust Timing Synchronization in Aeronautical Mobile Communication Systems

Science.gov (United States)

Xiong, Fu-Qin; Pinchak, Stanley

2004-01-01

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

The message is the message-maker.

Science.gov (United States)

Chalkley, A B

1977-03-01

For those engaged in family planning or other demographic work of an active kind, serious errors can be made and much money and skill wasted unless there is a clear idea of available means of communication. Literacy and media-diffusion figures offer vague parameters, especially in Asia, and the role of spoken communication -- considered key in "illiterate" societies -- is even more difficult to assess. For mass media, the starting point is "diffusion rates" representing numbers of TV sets owned or newspapers sold per 1000 population and so on -- measures of quantity. This article surveys the population growth rates, urban-rural distribution, educational levels, literacy rates, numbers of newspapers bought, radios and TVs owned (per 1000 population) for 12 Asian countries, and discusses their meaning in terms of media use. Chief among the points made are that print media still have an enormous role to play in the developing countries -- newspaper diffusion rates are quite high, even in countries with low urban population (especially India). The quality of electronic media (too often considered the natural "wave of the future" everywhere) varies but is generally not high. Where they are fully developed their role is vital -- but it might be noted that it is the message makers themselves who are most vital. Choosing the right medium and the proper message for it is essential.

Comparing tailored and untailored text messages for smoking cessation

DEFF Research Database (Denmark)

Skov-Ettrup, L S; Ringgaard, L W; Dalum, P

2014-01-01

The aim was to compare the effectiveness of untailored text messages for smoking cessation to tailored text messages delivered at a higher frequency. From February 2007 to August 2009, 2030 users of an internet-based smoking cessation program with optional text message support aged 15-25 years were...... of text messages increases quit rates among young smokers....

Motivating Smoking Cessation Text Messages: Perspectives from Pregnant Smokers.

Science.gov (United States)

Schindler-Ruwisch, Jennifer M; Leavitt, Leah E; Macherelli, Laura E; Turner, Monique M; Abroms, Lorien C

2018-06-01

The purpose of this research is to analyze cessation text-messages written by pregnant smokers to elucidate the target population's preferred content and message attributes. To achieve this goal, the objectives of this study are three-fold; to qualitatively code messages written by pregnant smokers for frame, type of appeal, and intended target. Study participants were recruited as part of a larger trial of pregnant smokers who were enrolled in a text-messaging program or control group and surveyed 1 month post-enrollment. Each participant was asked to write a brief message to another pregnant smoker and two independent coders qualitatively analyzed responses. User generated messages (N = 51) were equally loss and gain framed, and the most common appeals were: fear, guilt, cognitive, hope and empathy, in order of most to least frequent. The target of the majority of the messages was the baby. Allowing pregnant smokers to write cessation text-messages for other pregnant women can provide relevant insight into intervention content. Specifically, pregnant smokers appear to equally promote gain and loss frames, but may prefer messages that include components of fear and guilt related to the impact of smoking on their baby. Additional research is needed to systematically uncover perspectives of pregnant smokers to ensure interventions are optimally effective.

Creating Effective Media Messaging for Rural Smoke-free Policy.

Science.gov (United States)

Riker, Carol A; Butler, Karen M; Ricks, JaNelle M; Record, Rachael A; Begley, Kathy; Anderson, Debra Gay; Hahn, Ellen J

2015-01-01

Objectives were to (1) explore perceived effectiveness of existing smoke-free print advertisements in rural communities and (2) generate message content, characteristics, and media delivery channels that resonate with residents. Qualitative methods design. Thirty-nine rural adults recruited by community partners. Content analysis of findings from individuals in four focus groups who participated in general discussion and reviewed eight print ads related to secondhand smoke (SHS) and smoke-free policy. Six content themes were identified: smoking/SHS dangers, worker health, analogies, economic impact, rights, and nostalgia. Seven message characteristics were recognized: short/to the point, large enough to read, graphic images, poignant stories, statistics/charts/graphs, message sender, and messages targeting different groups. Four media delivery channels were considered most effective: local media, technology, billboard messages, and print materials. Seeking input from key informants is essential to reaching rural residents. Use of analogies in media messaging is a distinct contribution to the literature on effective smoke-free campaigns. Other findings support previous studies of effective messaging and delivery channels. Further research is needed to examine effectiveness of themes related to message content in smoke-free ads and delivery strategies. Effective media messaging can lead to policy change in rural communities to reduce exposure to SHS. © 2015 Wiley Periodicals, Inc.

Detection of generalized synchronization using echo state networks

Science.gov (United States)

Ibáñez-Soria, D.; Garcia-Ojalvo, J.; Soria-Frisch, A.; Ruffini, G.

2018-03-01

Generalized synchronization between coupled dynamical systems is a phenomenon of relevance in applications that range from secure communications to physiological modelling. Here, we test the capabilities of reservoir computing and, in particular, echo state networks for the detection of generalized synchronization. A nonlinear dynamical system consisting of two coupled Rössler chaotic attractors is used to generate temporal series consisting of time-locked generalized synchronized sequences interleaved with unsynchronized ones. Correctly tuned, echo state networks are able to efficiently discriminate between unsynchronized and synchronized sequences even in the presence of relatively high levels of noise. Compared to other state-of-the-art techniques of synchronization detection, the online capabilities of the proposed Echo State Network based methodology make it a promising choice for real-time applications aiming to monitor dynamical synchronization changes in continuous signals.

Synchronization of delay-coupled nonlinear oscillators : an approach based on the stability analysis of synchronized equilibria

NARCIS (Netherlands)

Michiels, W.; Nijmeijer, H.

2009-01-01

We consider the synchronization problem of an arbitrary number of coupled nonlinear oscillators with delays in the interconnections. The network topology is described by a directed graph. Unlike the conventional approach of deriving directly sufficient synchronization conditions, the approach of the

Synchronization and comparison of Lifelog audio recordings

DEFF Research Database (Denmark)

Nielsen, Andreas Brinch; Hansen, Lars Kai

2008-01-01

as a preprocessing step to select and synchronize recordings before further processing. The two methods perform similarly in classification, but fingerprinting scales better with the number of recordings, while cross-correlation can offer sample resolution synchronization. We propose and investigate the benefits...... of combining the two. In particular we show that the combination allows sample resolution synchronization and scalability....

A Spatiotemporal-Chaos-Based Cryptosystem Taking Advantage of Both Synchronous and Self-Synchronizing Schemes

Science.gov (United States)

Lü, Hua-Ping; Wang, Shi-Hong; Li, Xiao-Wen; Tang, Guo-Ning; Kuang, Jin-Yu; Ye, Wei-Ping; Hu, Gang

2004-06-01

Two-dimensional one-way coupled map lattices are used for cryptography where multiple space units produce chaotic outputs in parallel. One of the outputs plays the role of driving for synchronization of the decryption system while the others perform the function of information encoding. With this separation of functions the receiver can establish a self-checking and self-correction mechanism, and enjoys the advantages of both synchronous and self-synchronizing schemes. A comparison between the present system with the system of advanced encryption standard (AES) is presented in the aspect of channel noise influence. Numerical investigations show that our system is much stronger than AES against channel noise perturbations, and thus can be better used for secure communications with large channel noise.

Flow of Emotional Messages in Artificial Social Networks

Science.gov (United States)

Chmiel, Anna; Hołyst, Janusz A.

Models of message flows in an artificial group of users communicating via the Internet are introduced and investigated using numerical simulations. We assumed that messages possess an emotional character with a positive valence and that the willingness to send the next affective message to a given person increases with the number of messages received from this person. As a result, the weights of links between group members evolve over time. Memory effects are introduced, taking into account that the preferential selection of message receivers depends on the communication intensity during the recent period only. We also model the phenomenon of secondary social sharing when the reception of an emotional e-mail triggers the distribution of several emotional e-mails to other people.

Guide to Synchronization of Video Systems to IRIG Timing

Science.gov (United States)

1992-07-01

and industry. 1-2 CHAPTER 2 SYNCHRONISATION Before delving into the details of synchronization , a review is needed of the reasons for synchronizing ... Synchronization of Video Systems to IRIG Timing Optical Systems Group Range Commanders Council White Sands Missile Range, NM 88002-5110 RCC Document 456-92 Range...This document addresses a broad field of video synchronization to IRIG timing with emphasis on color synchronization . This document deals with

Subtle Messages.

Science.gov (United States)

Tamplin de Poinsot, Nan

1999-01-01

Describes a self-portrait assignment inspired by the work of Frida Kahlo. Discusses Frida Kahlo's artwork and use of surrealist and symbolist views. States that each student had to incorporate personal symbolism in the portrait to convey a message about him or herself in a subtle manner. (CMK)

Fabrication of seamless calandria tubes by cold pilgering route using 3-pass and 2-pass schedules

Science.gov (United States)

Saibaba, N.

2008-12-01

Calandria tube is a large diameter, extremely thin walled zirconium alloy tube which has diameter to wall thickness ratio as high as 90-95. Such tubes are conventionally produced by the 'welded route', which involves extrusion of slabs followed by a series of hot and cold rolling passes, intermediate anneals, press forming of sheets into circular shape and closing the gap by TIG welding. Though pilgering is a well established process for the fabrication of seamless tubes, production of extremely thin walled tubes offers several challenges during pilgering. Nuclear fuel complex (NFC), Hyderabad, has successfully developed a process for the production of Zircaloy-4 calandria tubes by adopting the 'seamless route' which involves hot extrusion of mother blanks followed by three-pass pilgering or two-pass pilgering schedules. This paper deals with standardization of the seamless route processes for fabrication of calandria tubes, comparison between the tubes produced by 2-pass and 3-pass pilgering schedules, role of ultrasonic test charts for control of process parameters, development of new testing methods for burst testing and other properties.

Fabrication of seamless calandria tubes by cold pilgering route using 3-pass and 2-pass schedules

International Nuclear Information System (INIS)

Saibaba, N.

2008-01-01

Calandria tube is a large diameter, extremely thin walled zirconium alloy tube which has diameter to wall thickness ratio as high as 90-95. Such tubes are conventionally produced by the 'welded route', which involves extrusion of slabs followed by a series of hot and cold rolling passes, intermediate anneals, press forming of sheets into circular shape and closing the gap by TIG welding. Though pilgering is a well established process for the fabrication of seamless tubes, production of extremely thin walled tubes offers several challenges during pilgering. Nuclear fuel complex (NFC), Hyderabad, has successfully developed a process for the production of Zircaloy-4 calandria tubes by adopting the 'seamless route' which involves hot extrusion of mother blanks followed by three-pass pilgering or two-pass pilgering schedules. This paper deals with standardization of the seamless route processes for fabrication of calandria tubes, comparison between the tubes produced by 2-pass and 3-pass pilgering schedules, role of ultrasonic test charts for control of process parameters, development of new testing methods for burst testing and other properties

Art messaging to engage homeless young adults.

Science.gov (United States)

Nyamathi, Adeline; Slagle, Alexandra; Thomas, Alexandra; Hudson, Angela; Kahilifard, Farinaz; Avila, Glenna; Orser, Julie; Cuchilla, Manuel

2011-01-01

Art has been shown to be an empowering and engaging entity with numerous benefits to vulnerable populations, including the homeless persons and young adults. However, little is known how homeless young adults perceive the use of art as messages that can communicate the danger of initiating or continuing drug and alcohol use. The purpose of this study was to solicit perspectives of homeless, drug-using young adults as to how art can be used to design messages for their peers about the danger of initiating or continuing drug and alcohol use. Qualitative methodology via focus group discussions was utilized to engage 24 homeless young adults enrolled from a drop-in site in Santa Monica, California. The findings revealed support for a myriad of delivery styles, including in-person communication, flyers, music, documentary film, and creative writing. The young adults also provided insight into the importance of the thematic framework of messages. Such themes ranged from empowering and hopeful messages to those designed to scare young homeless adults into not experimenting with drugs. The findings indicate that in addition to messages communicating the need to prevent or reduce drug and alcohol use, homeless young adults respond to messages that remind them of goals and dreams they once had for their future, and to content that is personal, real, and truthful. Our research indicates that messages that reinforce protective factors such as hope for the future and self-esteem may be as important to homeless young adults as information about the risks and consequences of drug use.

Quantum synchronization in an optomechanical system based on Lyapunov control.

Science.gov (United States)

Li, Wenlin; Li, Chong; Song, Heshan

2016-06-01

We extend the concepts of quantum complete synchronization and phase synchronization, which were proposed in A. Mari et al., Phys. Rev. Lett. 111, 103605 (2013)PRLTAO0031-900710.1103/PhysRevLett.111.103605, to more widespread quantum generalized synchronization. Generalized synchronization can be considered a necessary condition or a more flexible derivative of complete synchronization, and its criterion and synchronization measure are proposed and analyzed in this paper. As examples, we consider two typical generalized synchronizations in a designed optomechanical system. Unlike the effort to construct a special coupling synchronization system, we purposefully design extra control fields based on Lyapunov control theory. We find that the Lyapunov function can adapt to more flexible control objectives, which is more suitable for generalized synchronization control, and the control fields can be achieved simply with a time-variant voltage. Finally, the existence of quantum entanglement in different generalized synchronizations is also discussed.

A Semantics of Synchronization.

Science.gov (United States)

1980-09-01

suggestion of having very hungry philosophers. One can easily imagine the complexity of the equivalent implementation using semaphores . Synchronization types...Edinburgh, July 1978. [STAR79] Stark, E.W., " Semaphore Primitives and Fair Mutual Exclusion," TM-158, Laboratory for Computer Science, M.I.T., Cambridge...AD-AQ91 015 MASSACHUSETTS INST OF TECH CAMBRIDGE LAB FOR COMPUTE--ETC F/S 9/2 A SEMANTICS OF SYNCHRONIZATION .(U) .C SEP 80 C A SEAQUIST N00015-75

A qualitative study of college student responses to conflicting messages in advertising: anti-binge drinking public service announcements versus wine promotion health messages.

Science.gov (United States)

Ahn, Ho-Young; Wu, Lei; Kelly, Stephanie; Haley, Eric

2011-06-01

The purpose of this study was to investigate how college students deal with conflicting health messages in advertising regarding binge drinking and wine promotion. Phenomenological in-depth long interviews were conducted beyond the point of redundancy (N = 16). The results of this study indicated that students' meaning making regarding the conflicting messages relied greatly upon how consistent either message was with their prior beliefs about alcohol. Additionally, not all students perceived the messages to be contradictory; these students saw the messages as being constructed for different purposes and as such incomparable. Overall, students who perceived conflict responded to the topic with apathy fueled by advertising skepticism. Employing qualitative methodology to understand how college students respond to conflicting messages will assist health promotion practitioners develop more effective alcohol abuse prevention messages and provide suggestions for researchers for studying this phenomenon from other perspectives in the future. Implications are further discussed within.

A Self-Stabilizing Hybrid-Fault Tolerant Synchronization Protocol

Science.gov (United States)

Malekpour, Mahyar R.

2014-01-01

In this report we present a strategy for solving the Byzantine general problem for self-stabilizing a fully connected network from an arbitrary state and in the presence of any number of faults with various severities including any number of arbitrary (Byzantine) faulty nodes. Our solution applies to realizable systems, while allowing for differences in the network elements, provided that the number of arbitrary faults is not more than a third of the network size. The only constraint on the behavior of a node is that the interactions with other nodes are restricted to defined links and interfaces. Our solution does not rely on assumptions about the initial state of the system and no central clock nor centrally generated signal, pulse, or message is used. Nodes are anonymous, i.e., they do not have unique identities. We also present a mechanical verification of a proposed protocol. A bounded model of the protocol is verified using the Symbolic Model Verifier (SMV). The model checking effort is focused on verifying correctness of the bounded model of the protocol as well as confirming claims of determinism and linear convergence with respect to the self-stabilization period. We believe that our proposed solution solves the general case of the clock synchronization problem.

Military Message Experiment. Volume II.

Science.gov (United States)

1982-04-01

elements of the Department of Defense. This resulted in a memorandum from the Director, Telecomunications and Comand and Control, OSD, in June 1975...1978 to April 1979 and provides a discussion of the telecomunications inter- face aspects of the experiment. This Final Report covers the period of...arise in the telecomunication system which require A retransmission of an outgoing message. A "service" message may be created within the

Efficient Data Generation and Publication as a Test Tool

Science.gov (United States)

Einstein, Craig Jakob

2017-01-01

A tool to facilitate the generation and publication of test data was created to test the individual components of a command and control system designed to launch spacecraft. Specifically, this tool was built to ensure messages are properly passed between system components. The tool can also be used to test whether the appropriate groups have access (read/write privileges) to the correct messages. The messages passed between system components take the form of unique identifiers with associated values. These identifiers are alphanumeric strings that identify the type of message and the additional parameters that are contained within the message. The values that are passed with the message depend on the identifier. The data generation tool allows for the efficient creation and publication of these messages. A configuration file can be used to set the parameters of the tool and also specify which messages to pass.

Linear Synchronous Motor Repeatability Tests

International Nuclear Information System (INIS)

Ward, C.R.

2002-01-01

A cart system using linear synchronous motors was being considered for the Plutonium Immobilization Plant (PIP). One of the applications in the PIP was the movement of a stack of furnace trays, filled with the waste form (pucks) from a stacking/unstacking station to several bottom loaded furnaces. A system was ordered to perform this function in the PIP Ceramic Prototype Test Facility (CPTF). This system was installed and started up in SRTC prior to being installed in the CPTF. The PIP was suspended and then canceled after the linear synchronous motor system was started up. This system was used to determine repeatability of a linear synchronous motor cart system for the Modern Pit Facility

Chaos synchronizations of chaotic systems via active nonlinear control

International Nuclear Information System (INIS)

Huang, J; Xiao, T J

2008-01-01

This paper not only investigates the chaos synchronization between two LCC chaotic systems, but also discusses the chaos synchronization between LCC system and Genesio system. Some novel active nonlinear controllers are designed to achieve synchronizations between drive and response systems effectively. Moreover, the sufficient conditions of synchronizations are derived by using Lyapunov stability theorem. Numerical simulations are presented to verify the theoretical analysis, which shows that the synchronization schemes are global effective

Quantum synchronization of a driven self-sustained oscillator.

Science.gov (United States)

Walter, Stefan; Nunnenkamp, Andreas; Bruder, Christoph

2014-03-07

Synchronization is a universal phenomenon that is important both in fundamental studies and in technical applications. Here we investigate synchronization in the simplest quantum-mechanical scenario possible, i.e., a quantum-mechanical self-sustained oscillator coupled to an external harmonic drive. Using the power spectrum we analyze synchronization in terms of frequency entrainment and frequency locking in close analogy to the classical case. We show that there is a steplike crossover to a synchronized state as a function of the driving strength. In contrast to the classical case, there is a finite threshold value in driving. Quantum noise reduces the synchronized region and leads to a deviation from strict frequency locking.

Synchronization of modified Colpitts oscillators with structural perturbations

Energy Technology Data Exchange (ETDEWEB)

Kammogne, Soup Tewa; Fotsin, H B, E-mail: hbfotsin@yahoo.fr [Laboratoire d' electronique, Departement de Physique, Faculte des sciences, Universite de Dschang, PO Box 067, Dschang (Cameroon)

2011-06-01

This paper deals with the problem of the synchronization of uncertain modified Colpitts oscillators. Considering the effect of external disturbances on the system parameters and nonlinear control inputs, a robust controller based on Lyapunov theory is designed for the output synchronization between a slave system and a master system in order to ensure the synchronization of uncertain modified Colpitts oscillator systems. This approach was chosen not only to guarantee a stable synchronization but also to reduce the effect of external perturbation. Nonadaptive feedback synchronization with only one controller for the system is investigated. Numerical simulations are performed to confirm the efficiency of the proposed control scheme.

Stroboscope Based Synchronization of Full Frame CCD Sensors.

Science.gov (United States)

Shen, Liang; Feng, Xiaobing; Zhang, Yuan; Shi, Min; Zhu, Dengming; Wang, Zhaoqi

2017-04-07

The key obstacle to the use of consumer cameras in computer vision and computer graphics applications is the lack of synchronization hardware. We present a stroboscope based synchronization approach for the charge-coupled device (CCD) consumer cameras. The synchronization is realized by first aligning the frames from different video sequences based on the smear dots of the stroboscope, and then matching the sequences using a hidden Markov model. Compared with current synchronized capture equipment, the proposed approach greatly reduces the cost by using inexpensive CCD cameras and one stroboscope. The results show that our method could reach a high accuracy much better than the frame-level synchronization of traditional software methods.

19 CFR 4.7d - Container status messages.

Science.gov (United States)

2010-04-01

... 19 Customs Duties 1 2010-04-01 2010-04-01 false Container status messages. 4.7d Section 4.7d... TREASURY VESSELS IN FOREIGN AND DOMESTIC TRADES Arrival and Entry of Vessels § 4.7d Container status messages. (a) Container status messages required. In addition to the advance filing requirements pursuant...

Identifying spam e-mail messages using an intelligence algorithm

Directory of Open Access Journals (Sweden)

Parichehr Ghaedi

2014-06-01

Full Text Available During the past few years, there have been growing interests in using email for delivering various types of messages such as social, financial, etc. There are also people who use email messages to promote products and services or even to do criminal activities called Spam email. These unwanted messages are sent to different target population for different purposes and there is a growing interest to develop methods to filter such email messages. This paper presents a method to filter Spam email messages based on the keyword pattern. In this article, a multi-agent filter trade based on the Bayes rule, which has benefit of using the users’ interest, keywords and investigation the message content according to its topic, has been used. Then Nested Neural Network has been used to detect the spam messages. To check the authenticity of this proposed method, we test it for a couple of email messages, so that it could determine spams and hams from each other, effectively. The result shows the superiority of this method over the previous ones including filters with Multi-Layer Perceptron that detect spams.