Abstract: The understanding of emergent collective phenomena in natural and social systems has driven the interest of scientists from different disciplines during decades. Among these phenomena, the synchronization of a set of interacting individuals or units has been intensively studied because of its ubiquity in the natural world. In this Letter, we show how for fixed coupling strengths local patterns of synchronization emerge differently in homogeneous and heterogeneous complex networks, driving the process towards a certain global synchronization degree following different paths. The dependence of the dynamics on the coupling strength and on the topology is unveiled. This study provides a new perspective and tools to understand this emerging phenomena.

Abstract: Process mining aims at extracting information from event logs to capture the business process as it is being executed. Process mining is particularly useful in situations where events are recorded but there is no system enforcing people to work in a particular way. Consider for example a hospital where the diagnosis and treatment activities are recorded in the hospital information system, but where health-care professionals determine the "careflow." Many process mining approaches have been proposed in recent years. However, in spite of many researchers' persistent efforts, there are still several challenging problems to be solved. In this paper, we focus on mining non-free-choice constructs, i.e., situations where there is a mixture of choice and synchronization. Although most real-life processes exhibit non-free-choice behavior, existing algorithms are unable to adequately deal with such constructs. Using a Petri-net-based representation, we will show that there are two kinds of causal dependencies between tasks, i.e., explicit and implicit ones. We propose an algorithm that is able to deal with both kinds of dependencies. The algorithm has been implemented in the ProM framework and experimental results shows that the algorithm indeed significantly improves existing process mining techniques.

Abstract: Here we demonstrate a new method for droplet fusion based on a surface energy pattern on the walls of a microfluidic device, that does not require active elements nor accurate synchronization of the droplets.

Abstract: We study synchronization properties of general uncoupled limit-cycle oscillators driven by common and independent Gaussian white noises. Using phase reduction and averaging methods, we analytically derive the stationary distribution of the phase difference between oscillators for weak noise intensity. We demonstrate that in addition to synchronization, clustering, or more generally coherence, always results from arbitrary initial conditions, irrespective of the details of the oscillators.

Abstract: The present paper is mainly concerned with the issues of synchronization dynamics of complex delayed dynamical networks with impulsive effects. A general model of complex delayed dynamical networks with impulsive effects is formulated, which can well describe practical architectures of more realistic complex networks related to impulsive effects. Based on impulsive stability theory on delayed dynamical systems, some simple but less conservative criterion are derived for global synchronization of such dynamical network. It is shown that synchronization of the networks is heavily dependent on impulsive effects of connecting configuration in the networks. Furthermore, the theoretical results are applied to a typical SF network composing of impulsive coupled chaotic delayed Hopfield neural network nodes, and are also illustrated by numerical simulations.

Abstract: This paper investigates the synchronization scheme of coupled neural networks with time delays. The coupling function, which can be linear or nonlinear, is subject to uncertainties in the network. By utilizing the stability theory for impulsive functional differential equations, several new criteria are obtained to ensure the robust synchronization of coupled networks via impulsive control. Furthermore, an estimation of the predicted stable region is derived to facilitate the design of the control gain. Finally, numerical simulations are presented to demonstrate the effectiveness of our results.

Abstract: The brain is one of the most complex systems in nature, with a structured complex connectivity. Recently, large-scale corticocortical connectivities, both structural and functional, have received a great deal of research attention, especially using the approach of complex network analysis. Understanding the relationship between structural and functional connectivity is of crucial importance in neuroscience. Here we try to illuminate this relationship by studying synchronization dynamics in a realistic anatomical network of cat cortical connectivity. We model the nodes (cortical areas) by a neural mass model (population model) or by a subnetwork of interacting excitable neurons (multilevel model). We show that if the dynamics is characterized by well-defined oscillations (neural mass model and subnetworks with strong couplings), the synchronization patterns are mainly determined by the node intensity (total input strengths of a node) and the detailed network topology is rather irrelevant. On the other hand, the multilevel model with weak couplings displays more irregular, biologically plausible dynamics, and the synchronization patterns reveal a hierarchical cluster organization in the network structure. The relationship between structural and functional connectivity at different levels of synchronization is explored. Thus, the study of synchronization in a multilevel complex network model of cortex can provide insights into the relationship between network topology and functional organization of complex brain networks.

Abstract: Chaos synchronization is a very important nonlinear phenomenon, which has been studied to date extensively on dynamical systems described by real variables. There also exist, however, interesting cases of dynamical systems, where the main variables participating in the dynamics are complex, for example, when amplitudes of electromagnetic fields are involved. Another example is when chaos synchronization is used for communications, where doubling the number of variables may be used to increase the content and security of the transmitted information. It is also well-known that similar generalization of the Lorenz system to one with complex ODEs has been introduced to describe and simulate the physics of a detuned laser and thermal convection of liquid flows. In this paper, we study chaos synchronization by applying active control and Lyapunov function analysis to two such systems introduced by Chen and Lu. First we show that, written in terms of complex variables, these systems can have chaotic dynamics and...

Abstract: Smart sensors densely distributed over structures can provide rich information for structural monitoring using their onboard wireless communication and computational capabilities However, issues such as time synchronization error, data loss, and dealing with large amounts of harvested data have limited the implementation of full-fledged systems Limited network resources (eg battery power, storage space, bandwidth, etc) make these issues quite challenging This paper first investigates the effects of time synchronization error and data loss, aiming to clarify requirements on synchronization accuracy and communication reliability in SHM applications Coordinated computing is then examined as a way to manage large amounts of data

Abstract: In this paper, the adaptive synchronization and lag synchronization are considered for uncertain dynamical system with time delay based on parameter identification and a novel control method is then further given using the Lyapunov functional method. With this new and effective method, parameter identification and lag synchronization can be achieved simultaneously. Simulation results are given to justify the theoretical analysis in this paper.

Abstract: As multicore systems continue to gain ground in the High Performance Computing world, linear algebra algorithms have to be reformulated or new algorithms have to be developed in order to take advantage of the architectural features on these new processors. Fine grain parallelism becomes a major requirement and introduces the necessity of loose synchronization in the parallel execution of an operation. This paper presents an algorithm for the QR factorization where the operations can be represented as a sequence of small tasks that operate on square blocks of data. These tasks can be dynamically scheduled for execution based on the dependencies among them and on the availability of computational resources. This may result in an out of order execution of the tasks which will completely hide the presence of intrinsically sequential tasks in the factorization. Performance comparisons are presented with the LAPACK algorithm for QR factorization where parallelism can only be exploited at the level of the BLAS operations.

Abstract: Rather than costly modifications to existing radars, a small, low cost radar warning receiver is used to monitor the RF environment. This add-on receiver can provide situational awareness including RF signal levels and angle of arrival, and recommend or provide antenna scanning synchronization, blanking inputs or gated reactionary outputs to or for the airborne radar. Utilization of this information can be used to reduce false alarms and improve system performance.

Abstract: A fluid infusion system as described herein includes a number of local “body network” devices, such as an infusion pump, a handheld monitor or controller, a physiological sensor, and a bedside or hospital monitor. The body network devices can be configured to support communication of status data, physiological information, alerts, control signals, and other information between one another. In addition, the body network devices can be configured to support networked communication of status data, physiological information, alerts, control signals, and other information between the body network devices and “external” devices, systems, or communication networks. The networked medical devices are configured to support a variety of wireless data communication protocols for efficient communication of data within the medical device network. In addition, the wireless medical devices may be configured to support a number of dynamically adjustable wireless data communication modes to react to current operating conditions, application-specific data content, or other criteria.

Abstract: A simple but efficient method for chaos synchronization of fractional differential systems is proposed, which is based upon the stability criterion of linear fractional differential systems. Using this new method, chaos synchronization for fractional Lorenz, Rossler, and Chen systems are implemented.

Abstract: When assessing human emotion using EEG classification, one of the critical problems is to deal with the very large number of features to be classified. In this paper, we address this problem using synchronization likelihood as a new channel selection method. Applying this method, we could significantly reduce the number of EEG channels to be used in emotion assessment, with only slight (if any) loss of classification performance depending on the used feature. We report and compare the results obtained by employing a linear classifier on different features extracted either from all channels or from the selected subset of channels. These features include synchronization likelihood, Hjorth parameters, and fractal dimension.

Abstract: We investigate in depth the synchronization of coupled oscillators on top of complex networks with different degrees of heterogeneity within the context of the Kuramoto model. In a previous paper [Phys. Rev. Lett. 98, 034101 (2007)], we unveiled how for fixed coupling strengths local patterns of synchronization emerge differently in homogeneous and heterogeneous complex networks. Here, we provide more evidence on this phenomenon, extending the previous work to networks that interpolate between homogeneous and heterogeneous topologies. We also introduce details of the path towards synchronization for the evolution of clustering in the synchronized patterns. Finally, we investigate the synchronization of networks with modular structure and conclude that, in these cases, local synchronization is first attained at the most internal level of organization of modules, progressively evolving to the outer levels as the coupling constant is increased. The present work introduces parameters that are proved to be useful for the characterization of synchronization phenomena in complex networks.

Abstract: In wireless sensor networks, distributed timing synchronization based on pulse-coupled oscillators at the physical layer is currently being investigated as an interesting alternative to packet synchronization. In this paper, the convergence properties of such a system are studied through algebraic graph theory, by modeling the nodes as discrete-time clocks. A general scenario where clocks may have different free-oscillation frequencies is considered, and both time-invariant and time-variant network topologies (or fading channels) are discussed. Furthermore, it is shown that the system of oscillators can be studied as a set of coupled discrete-time PLLs. Based on this observation, a generalized system design is discussed, and it is proved that known results in the context of conventional PLLs for carrier acquisition have a counterpart in distributed systems. Finally, practical details of the implementation of the distributed synchronization algorithm over a bandlimited noisy channel are covered.

Abstract: Much recent empirical evidence shows that community structure is ubiquitous in the real-world networks. In this paper we propose a growth model to create scale-free networks with the tunable strength (noted by Q ) of community structure and investigate the influence of community strength upon the collective synchronization induced by Susceptive-Infected-Recovery-Susceptive (SIRS) epidemiological process. Global and local synchronizability of the system is studied by means of an order parameter and the relevant finite-size scaling analysis is provided. The numerical results show that a phase transition occurs at Qc approximately or equal to 0.835 from global synchronization to desynchronization and the local synchronization is weakened in a range of intermediately large Q. Moreover, we study the impact of mean degree upon synchronization on scale-free networks.

Abstract: This article investigates the H∞ synchronization problem for a general class of chaotic systems. Based on Lyapunov theory, linear matrix inequality (LMI) and linear matrix equality (LME) formulation, the output feedback controller is established to not only guarantee stable synchronization of both master and slave systems but also reduce the effect of external disturbance to an H∞-norm constraint. Two illustrative examples are provided to demonstrate the effectiveness of the developed theoretical results.

Abstract: Efficient fine-grain synchronization is extremely important to effectively harness the computational power of many-core architectures. However, designing and implementing finegrain synchronization in such architectures presents several challenges, including issues of synchronization induced overhead, storage cost, scalability, and the level of granularity to which synchronization is applicable. This paper proposes the Synchronization State Buffer (SSB), a scalable architectural design for fine-grain synchronization that efficiently performs synchronizations between concurrent threads. The design of SSB is motivated by the following observation: at any instance during the parallel execution only a small fraction of memory locations are actively participating in synchronization. Based on this observation we present a fine-grain synchronization design that records and manages the states of frequently synchronized data using modest hardware support. We have implemented the SSB design in the context of the 160-core IBM Cyclops-64 architecture. Using detailed simulation, we present our experience for a set of benchmarks with different workload characteristics.

Abstract: This invention discloses a method for synchronizing a plurality of devices, including: obtaining, by a first device, an extended address of an informational node of a plurality of informational nodes of a second device, the plurality of informational nodes arranged in a hierarchical tree structure; and utilizing the extended address to locate the informational node amongst the tree structure to enable synchronization of the informational node; wherein the extended address includes a hierarchical location of the informational node. This invention further discloses a system, client and server for data sync, and the folder-level data sync can be implemented by using the method of this invention.

Abstract: A computer system comprises servers running application programs which are controlled, at least in part, by configuration parameters. The parameters are updated by first updating a database of configuration parameters, and then automatically updating the servers in accordance with the database updates to automatically maintain synchronization between the server configuration and the database.

Abstract: The book addresses the study and design of efficient and flexible physical layers for broadband mobile and fixed satellite links. The chapters focus on long-term developments addressing advanced physical layer techniques for braodband communications, fixed and mobile terminals, and 4G evolutions with possible convergence betwee different technologies. The book provides a unified view of services and applications, fundamental theories, channel coding, modulation, synchronization and parameter estimation, distortions and countermeasures, diversity techniques, multiplexing and multiple access schemes, and software radio.

Abstract: Two major trends are converging to reshape the landscape of concurrent object-oriented programming languages. First, trends in modern architectures (multi-core, accelerators, high performance clusters such as Blue Gene) are making concurrency and distribution inescapable for large classes of OO programmers. Second, experience with first-generation concurrent OO languages (e.g. Java threads and synchronization) have revealed several drawbacks of unstructured threads with lock-based synchronization.X10 is a second generation OO language designed to address both programmer productivity and parallel performance for modern architectures. It extends sequential Java with a handful of constructs for concurrency and distribution. It introduces a clustered address space to deal with distribution. A computation is thought of as running at multiple places, with many simultaneous activities operating in each place. Objects and activities once created in a particular place stay confined to that place. However, a data-structure (object) allocated in one place may contain a reference to an object allocated in anoter place. (Thus X10 supports a partitioned global address space.X10 is an explicitly concurrent language. It provides constructs for lightweight asynchrony, making it easy for programmers to write code for target architectures that provide massive parallelism. It provides for recursive fork-join parallelism for structured concurrency. It provides for termination detection so that collections of activities may be reliably sequenced (even if they run across multiple places). It provides for a very simple form of atomic blocks in lieu of locks for mutual exclusion. These constructs can be used to define more sophisticated synchronization constructs such as futures and clocks.X10 supports a rich notion of multi-dimensional index spaces (regions), together with a rich set of operations on regions. Regions are first-class data-structures -- they can be produced dynamically, stored in data-structures, passed around in method invocations etc. A distributed version of regions (distributions) is also defined. It specifies a mapping of every point in the underlying region to a place. An array is simply a mapping from a distribution to backing store of the given type, partitioned across various places in the manner described by the distribution.Rank-generic programming is supported through generic points. Parallel iteration constructs are also provided.X10 provides a rich framework for constraint-based value-dependent types. The programmer may specify types -- such as the type of square arrays of doubles of rank 2 -- which reference run-time constant (final) values. Classes and interfaces can be parametrized with properties, which are to be thought of as final instance fields. A dependent type is merely a constraint over these properties. Types are checked statically; this requires the compiler to use a constraint-solver. The design of the type-system and the implementation is modular so that a new constraint system can be defined and plugged into the language in a fairly routine fashion. Dynamic casts are also provided -- this permits an object to be checked at runtime for conformance to a dependent type. The compiler takes care of generating run-time code for performing such tests.The tutorial illustrate how common design patterns for concurrency and distribution can be naturally expressed in X10 (wait-free algorithms, data-flow synchronization, streaming parallelism, co-processor parallelism, hierarchical task-parallelism and phased computations). It shows design patterns for establishing that programs are determinate and/or deadlock-free. Examples are drawn from high-performance computing and middleware (transactions, event-driven computing).Participants will be encouraged to download the X10 implementation from SourceForge http://x10.sf.net. The source code for the implementation is released under the Eclipse Public Licence. The implementation consists of a translator from X10 to Java, and a multi-threaded runtime system in Java. Resulting programs may be run on any SMP that supports a Java Virtual Machine.

Abstract: A new general complex delayed dynamical network model with nonsymmetric coupling is introduced, and then we investigate its synchronization phenomena. Several synchronization criteria for delay-independent and delay-dependent synchronization are provided which generalize some previous results. The matrix Jordan canonical formalization method is used instead of the matrix diagonalization method, so in our synchronization criteria, the coupling configuration matrix of the network does not required to be diagonalizable and may have complex eigenvalues. Especially, we show clearly that the synchronizability of a delayed dynamical network is not always characterized by the second-largest eigenvalue even though all the eigenvalues of the coupling configuration matrix are real. Furthermore, the effects of time-delay on synchronizability of networks with unidirectional coupling are studied under some typical network structures. The results are illustrated by delayed networks in which each node is a two-dimensional limit cycle oscillator system consisting of a two-cell cellular neural network, numerical simulations show that these networks can realize synchronization with smaller time-delay, and will lose synchronization when the time-delay increase larger than a threshold.

Abstract: In an ad hoc peer-to-peer communications network, timing synchronization is facilitated between two or more nodes. A node can establish an original symbol timing and receive a first timing synchronization symbol from a peer node. A timing adjustment can be calculated based in part on the first timing synchronization symbol. An adjusted symbol timing can be established by adjusting the first symbol timing by the calculated timing adjustment amount. The adjusted symbol timing can be conveyed to one or more peer nodes, in order to facilitate timing synchronization among the nodes.

Abstract: Methods, apparatuses, and articles for synchronizing contents of associated computing devices are described herein In various embodiments, the method includes receiving, by a first computing device, from a shared server, a notification that content on a second computing device has been created or updated The first computing device may also request at least a first portion of the created/updated content from the second computing device to contribute to synchronizing the first and second computing devices with respect to the content Further, the first computing device may receive at least a second portion of the created/updated content from the second computing device to effectuate said contribution to synchronizing the first and second computing devices with respect to the content