Sensorimotor synchronisation

ltra-wideband (UWB) radio is a fast emerging technology with uniquely attractive features inviting major advances in wireless communications, networking, radar, imaging, and positioning systems. By its rulemaking proposal in 2002, the Federal Communications Commission (FCC) in the United States essentially unleashed huge "new bandwidth'' (3.6-10.1 GHz) at the noise floor, where UWB radios overlaying coexistent RF systems can operate using low-power ultra-short information bearing pulses. With similar regulatory processes currently under way in many countries worldwide, industry, government agencies, and academic institutions responded to this FCC ruling with rapidly growing research efforts targeting a host of exciting UWB applications: short-range very high-speed broadband access to the Internet, covert communication links, localization at centimeter-level accuracy, high-resolution ground-penetrating radar, through-wall imaging, precision navigation and asset tracking, just to name a few. This tutorial focuses on UWB wireless communications at the physical layer. It overviews the state-of-the-art in channel modeling, transmitters, and receivers of UWB radios, and outlines research directions and challenges to be overcome. As signal processing expertise is expected to have major impact in research and development of UWB systems, emphasis is placed on DSP aspects.

This article examines how Modern theories of mind remain even in some materialistic and hence ontologically anti-dualistic views; and shows how Dewey, anticipating Merleau-Ponty and 4E cognitive scientists, repudiates these theories. Throughout I place Dewey’s thought in the context of scientific inquiry, both recent and historical and including the cognitive as well as traditional sciences; and I show how he incorporated sciences of his day into his thought, while also anticipating enactive cognitive science. While emphasizing Dewey’s continued relevance, my main goal is to show how his scientifically informed account of perception and cognition combats skepticism propagated by certain scientific visions, exacerbated by commonplace notions about mind, that jointly suggest that human beings lack genuine access to reality.

This paper presents a grid-connected photovoltaic (PV) system with a three level voltage source converter (VSC) using double closed loop control strategy. The outer DC voltage control loop is to regulate the DC bus voltage, and the inner current control loop is to synchronize the output current with the grid voltage, thus ensuring unity power factor. A LLC resonant DC-DC converter is used in the proposed system to step-up the voltage of the PV array and to extract maximum power. It is intrinsically isolated by a high frequency transformer, then the parasitic capacitance of the PV panels to ground could not be of concern; furthermore, because of soft switching technique, it operates at high frequency with low switching losses. Size and cost of the magnetic components and DC-link capacitor are decreased compared with traditional boost converters. An incremental conductance method integrated within PI controller was used to extract maximum power by PV. Simulation results based on MATLAB/Simulink verify the validity and dynamic performance of the proposed system during fast solar irradiation changes and ensure DC bus voltage stability.

Quantum memory is important to quantum information processing in many ways: a synchronization device to match various processes within a quantum computer, an identity quantum gate that leaves any state unchanged, and a tool to convert heralded photons to photons-on-demand. In addition to quantum computing, quantum memory would be instrumental for the implementation of long-distance quantum communication using quantum repeaters. The importance of this basic quantum gate is exemplified by the multitude of optical quantum memory mechanisms being studied: optical delay lines, cavities, electromagnetically-induced transparency, photon-echo, and off-resonant Faraday interaction. Here we report on the state-of-the-art in the field of optical quantum memory, including criteria for successful quantum memory and current performance levels.

An accurate and less-disturbing active antiislanding method suitable for grid-connected converters using phase-locked loop (PLL) based grid synchronization is proposed in this paper. The orthogonal signal generator required by a single-phase PLL is built using a second-order generalized integrator. The inverter current reference is slightly modified each output cycle by an injected signal, and a feedback signal is extracted from the voltage of the point of common coupling (PCC). When the grid becomes unavailable, the feedback signal moves outside of a preset threshold value. The disturbance caused by this method is small compared to other active antiislanding methods, such as active frequency drift or frequency shift up/down. The method does not affect the zero crossing of the injected current, can be used to estimate the grid impedance, and is highly robust to different grid disturbances and stiffness. The performance of the proposed method has been studied through extensive simulations using MATLAB/Simulink and experiments. Selected results are presented to confirm its validity.

The latest research works on the synchronization scheme for either continuous transmission mode or burst packet transmission mode for the wireless OFDM communications are overviewed in this paper. The typical algorithms dealing with the symbol timing synchronization, the carrier frequency synchronization as well as the sampling clock synchronization are briefly introduced and analyzed. Three improved methods for the fine symbol timing synchronization in frequency domain are also proposed, with several key issues on the synchronization for the OFDM systems discussed.

Recently higher rates of autism diagnosis suggest involvement of environmental factors in causing this developmental disorder, in concert with genetic risk factors. Autistic children exhibit evidence of oxidative stress and impaired methylation, which may reflect effects of toxic exposure on sulfur metabolism. We review the metabolic relationship between oxidative stress and methylation, with particular emphasis on adaptive responses that limit activity of cobalamin and folate-dependent methionine synthase. Methionine synthase activity is required for dopamine-stimulated phospholipid methylation, a unique membrane-delimited signaling process mediated by the D4 dopamine receptor that promotes neuronal synchronization and attention, and synchrony is impaired in autism. Genetic polymorphisms adversely affecting sulfur metabolism, methylation, detoxification, dopamine signaling and the formation of neuronal networks occur more frequently in autistic subjects. On the basis of these observations, a ''redox/methylation hypothesis of autism'' is described, in which oxidative stress, initiated by environment factors in genetically vulnerable individuals, leads to impaired methylation and neurological deficits secondary to reductions in the capacity for synchronizing neural networks. #

The use of networks for communications between the electronic control units (ECU) of a vehicle in production cars dates from the beginning of the 1990s. The specific requirements of the different car domains have led to the development of a large number of automotive networks such as Local Interconnect Network, J1850, CAN, TTP/C, FlexRay, media-oriented system transport, IDB1394, etc. This paper first introduces the context of in-vehicle embedded systems and, in particular, the requirements imposed on the communication systems. Then, a comprehensive review of the most widely used automotive networks, as well as the emerging ones, is given. Next, the current efforts of the automotive industry on middleware technologies, which may be of great help in mastering the heterogeneity, are reviewed. Finally, we highlight future trends in the development of automotive communication systems.

This study tested the two following hypotheses: (i) compared with non-athletes, elite athletes are characterized by a reduced cortical activation during the preparation of precise visuo-motor performance; (ii) in elite athletes, an optimal visuo-motor performance is related to a low cortical activation. To this aim, electroencephalographic (EEG; 56 channels; Be Plus EB-Neuro) data were recorded in 18 right-handed elite air pistol shooters and 10 right-handed non-athletes. All subjects performed 120 shots. The EEG data were spatially enhanced by surface Laplacian estimation. With reference to a baseline period, power decrease/increase of alpha rhythms during the preshot period indexed the cortical activation/deactivation (event-related desynchronization/synchronization, ERD/ERS). Regarding the hypothesis (i), low-(about 8-10 Hz) and high-frequency (about 10-12 Hz) alpha ERD was lower in amplitude in the elite athletes than in the non-athletes over the whole scalp. Regarding the hypothesis (ii), the elite athletes showed high-frequency alpha ERS (about 10-12 Hz) larger in amplitude for high score shots (50%) than for low score shots; this was true in right parietal and left central areas. A control analysis confirmed these results with another indicator of cortical activation (beta ERD, about 20 Hz). The control analysis also showed that the amplitude reduction of alpha ERD for the high compared with low score shots was not observed in the non-athletes. The present findings globally suggest in Wiley InterScience (www.

Observation of human-induced large-amplitude lateral vibration of an actual pedestrian bridge in an extremely congested condition is reported. Walking motions of pedestrians recorded by a video camera are analysed. It is found that walking among 20 per cent or more of the pedestrians on the bridge was synchronized to the girder lateral vibration. With this synchronization, the total lateral force from the pedestrians to the girder is evidently increased and it acts as a resonant force on the girder lateral vibration.

Objective: To analyze the functional connectivity patterns of the EEG slow-wave activity during the different sleep stages and Cyclic Alternating Pattern (CAP) conditions, using concepts derived from Graph Theory. Methods: We evaluated spatial patterns of EEG slow-wave synchronization between all possible pairs of electrodes (19) placed over the scalp of 10 sleeping healthy young normal subjects using two graph theoretical measures: the clustering coefficient (Cp) and the characteristic path length (Lp). The measures were obtained during the different sleep stages and CAP conditions from the real EEG connectivity networks and randomized control (surrogate) networks (Cp-s and Lp-s). Results: Cp and Cp/Cp-s increased significantly from wakefulness to sleep while Lp and Lp/Lp-s did not show changes. Cp/Cp-s was higher for A1 phases, compared to B phases of CAP. Conclusions: The network organization of the EEG slow-wave synchronization during sleep shows features characteristic of small-world networks (high Cp combined with low Lp); this type of organization is slightly but significantly more evident during the CAP A1 subtypes. Significance: Our results show feasibility of using graph theoretical measures to characterize the complexity of brain networks during sleep and might indicate sleep, and the A1 phases of CAP in particular, as a period during which slow-wave synchronization shows optimal network organization for information processing.

Grid-connected converters rely on fast and accurate detection of the phase angle, amplitude and frequency of the utility voltage to guarantee the correct generation of the reference signals. An important issue associated with accurate grid voltage monitoring is the presence of an offset in the measured grid voltage. This voltage offset is typically introduced by the measurements and data conversion processes and causes errors for the estimated parameters of the grid voltage. Accordingly, this paper presents an offset rejection method for grid-connected converters based on a Phase-Locked-Loop (PLL) technique. The offset rejection method relies on the Second Order Generalized Integrator (SOGI) having the advantages of a simple implementation independent of the grid frequency and avoidance of filtering delays due to its resonance at the fundamental frequency. Selected experimental results validate the performance and robustness of the proposed offset rejection method.

Previous research has established that skilled joint action partners use predictive models to achieve temporal coordination, for instance, when playing a music duet. But how do joint action partners with different skill levels achieve coordination? Can experts predict the suboptimal timing of novices? What kind of information allows them to predict novices' timing? To address these questions, we asked skilled pianists to perform duets with piano novices. We varied whether, prior to performing duets, experts were familiar with novices' performances of their individual parts of the duets and whether experts had access to the musical scores including the novices' part of the duet. Familiarity with the score led to better coordination when the score implied a difficult passage. Familiarity with novices' performances led to better joint action coordination for the remaining parts of the duet. Together, the results indicate that experts are surprisingly flexible in predicting novices' suboptimal timing.

Conventional vibration signal processing techniques are most suitable for stationary processes. However, most mechanical faults in machinery reveal themselves through transient events in vibration signals. Timeseries modelling, including autoregressive moving average (ARMA) modelling and autoregressive (AR) modelling, is an efficient approach for transient signal analysis. Based on the adaptive prediction technique, this paper applies the principle of the adaptive line enhancer (ALE) to the modelling of transient vibration signals. The time-series models, adaptive algorithms and the rational time-frequency transfer function are investigated in the paper. Simulation and experimental studies with different time-frequency-amplitude distributions and transient vibration responses are described. The results show that the adaptive modelling method can trace the time-frequency signal and extract dynamic features such as time-frequency distributions and time-amplitude distributions from sample signals. Given the simple programming and potentially easy implementation in on-line applications, this method should have application in machine monitoring and fault diagnosis. r

We report about the first X-band spaceborneairborne bistatic synthetic aperture radar (SAR) experiment, conducted early November 2007, using the German satellite TerraSAR-X as transmitter and the German Aerospace Center's (DLR) new airborne radar system F-SAR as receiver. The importance of the experiment resides in both its pioneering character and its potential to serve as a test bed for the validation of nonstationary bistatic acquisitions, novel calibration and synchronization algorithms, and advanced imaging techniques. Due to the independent operation of the transmitter and receiver, an accurate synchronization procedure was needed during processing to make high-resolution imaging feasible. Precise phase-preserving bistatic focusing can only be achieved if time and phase synchronization exist. The synchronization approach, based on the evaluation of the range histories of several reference targets, was verified through a separate analysis of the range and Doppler contributions. After successful synchronization, nonstationary focusing was performed using a bistatic backprojection algorithm. During the campaign, stand-alone TerraSAR-X monostatic as well as interoperated TerraSAR-X/F-SAR bistatic data sets were recorded. As expected, the bistatic image shows a space-variant behavior in spatial resolution and in signal-to-noise ratio. Due to the selected configuration, the bistatic image outperforms its monostatic counterpart in almost the complete imaged scene. A detailed comparison between monostatic and bistatic images is given, illustrating the complementarity of both measurements in terms of backscatter and Doppler information. The results are of fundamental importance for the development of future nonsynchronized bistatic SAR systems.

Linear models have been used in several contexts to study the mechanisms that underpin sensorimotor synchronization. Given that their parameters are often linked to psychological processes such as phase correction and period correction, the fit of the parameters to experimental data is an important practical question. We present a unified method for parameter estimation of linear sensorimotor synchronization models that extends available techniques and enhances their usability. This method enables reliable and efficient analysis of experimental data for single subject and multi-person synchronization. In a previous paper (Jacoby et al., 2015), we showed how to significantly reduce the estimation error and eliminate the bias of parameter estimation methods by adding a simple and empirically justified constraint on the parameter space. By applying this constraint in conjunction with the tools of matrix algebra, we here develop a novel method for estimating the parameters of most linear models described in the literature. Through extensive simulations, we demonstrate that our method reliably and efficiently recovers the parameters of two influential linear models: Vorberg and Wing (1996), and Schulze et al. (2005), together with their multi-person generalization to ensemble synchronization. We discuss how our method can be applied to include the study of individual differences in sensorimotor synchronization ability, for example, in clinical populations and ensemble musicians.

Near Future on-board Telemetry, Tracking and Command (TT&C) equipment for secure communications will likely adopt Frequency Hopping (FH) instead of Direct Sequence (DS) Spread Spectrum (SS) techniques. As far as TT&C systems will have to cope with jammer-to-signal power ratios higher than 50 dB, classical DS approaches must be abandoned in favour of more robust FH solutions. In the following paper we present an overview of synchronization, channel coding and modulation issues for next generation anti-jamming TT&C transponder under study and design at Alcatel Alenia Space -Italy (AAS-I).

The FPGA technology has been playing a considerable role in portable and mobile communication. This is due to the features of flexibility, accuracy and configurability in designing and implementation. The paper presents a complete design for a 16-QAM transmitter and receiver based on the Virtex4 FPGA Kit. The implemented system can be applied in particle. Based on the principles of carrier synchronization, time synchronization, core tools for phase-different detecting as well as adaptive equalization processing in System Generator (a software of Xilinx), the authors have designed a complete baseband IF 16-QAM system, in which the baseband signal is upconverted into IF frequency (up to 12MHz) at the transmitter and then is downconverted at the receiver. After timing synchronizing, the adaptive equalizing and phase recovering, the received baseband signal is displayed in the oscilloscope's screen. These accurate experiments conducted in Virtex 4 FPGA board kit have shown a promising foundation for developing coding, algorithms in 16-QAM modulation scheme.

Power electronics based MicroGrids consist of a number of voltage source inverters (VSIs) operating in parallel. In this paper, the modeling, control design, and stability analysis of parallel connected three-phase VSIs are derived. The proposed voltage and current inner control loops and the mathematical models of the VSIs are based on the stationary reference frame. A hierarchical control scheme for the paralleled VSI system is developed comprising two levels. The primary control includes the droop method and the virtual impedance loops, in order to share active and reactive power. The secondary control restores the frequency and amplitude deviations produced by the primary control. Also, a synchronization algorithm is presented in order to connect the MicroGrid to the grid. Experimental results are provided to validate the performance and robustness of the parallel VSI system control architecture.

In the present study, we compared an experimental group of preschool children (n ¼ 22; mean age ¼ 5 years, 8 months) who followed an 8-week dance program with a control group (n ¼ 20; mean age ¼ 5 years, 5 months) on pre-post measures of sensorimotor synchronization (K-Rhythm Test), balancing on one leg and movement reaction time. Compared with the control participants, the dance group demonstrated significantly better pretest to posttest improvements on sensorimotor synchronization and balance (but not movement reaction time). Considering the importance of sensorimotor synchronization and balance for subsequent child development and performance of daily and sport activities, these results suggest that dancing should be included in early childhood curricula.

Advances in image sensors and evolution of digital computation is a strong stimulus for development and implementation of sophisticated methods for capturing, processing and analysis of 3-D data from dynamic scenes. Research on perspective time-varying 3-D scene capture technologies is important for the upcoming 3DTV displays. Methods such as shape-from-texture, shape-from-shading, shape-from-focus, and shape-from-motion extraction can restore 3-D shape information from a single camera data. The existing techniques for 3-D extraction from single-camera video sequences are especially useful for conversion of the already available vast mono-view content to the 3DTV systems. Sceneoriented single-camera methods such as human face reconstruction and facial motion analysis, body modeling and body motion tracking, and motion recognition solve efficiently a variety of tasks. 3-D multicamera dynamic acquisition and reconstruction, their hardware specifics including calibration and synchronization and software demands form another area of intensive research. Different classes of multiview stereo algorithms such as those based on cost function computing and optimization, fusing of multiple views, and feature-point reconstruction are possible candidates for dynamic 3-D reconstruction. High-resolution digital holography and pattern projection techniques such as coded light or fringe projection for real-time extraction of 3-D object positions and color information could manifest themselves as an alternative to traditional camera-based methods. Apart from all of these approaches, there also are some active imaging devices capable of 3-D extraction such as the 3-D time-of-flight camera, which provides 3-D image data of its environment by means of a modulated infrared light source.

Wireless Sensor Networks (WSNs) can take advantage of versatility, completeness, and low prices of standard wireless protocols; Bluetooth as we will show later is a candidate suitable for WSNs. The fusion of data collected over a WSN is just an evident application of time synchronization. Bringing together these two issues, we find that synchronization using standard protocols poses an important drawback. In this paper, we present a simple method that allows clock synchronization in Bluetooth WSNs, down to few microseconds.

Power electronics based MicroGrids consist of a number of voltage source inverters (VSIs) operating in parallel. In this paper, the modeling, control design, and stability analysis of parallel connected three-phase VSIs are derived. The proposed voltage and current inner control loops and the mathematical models of the VSIs are based on the stationary reference frame. A hierarchical control scheme for the paralleled VSI system is developed comprising two levels. The primary control includes the droop method and the virtual impedance loops, in order to share active and reactive power. The secondary control restores the frequency and amplitude deviations produced by the primary control. Also, a synchronization algorithm is presented in order to connect the MicroGrid to the grid. Experimental results are provided to validate the performance and robustness of the parallel VSI system control architecture.

Clock distribution networks synchronize the flow of data signals among synchronous data paths. The design of these networks can dramatically affect system-wide performance and reliability. A theoretical background of clock skew is provided in order to better understand how clock distribution networks interact with data paths. Minimum and maximum timing constraints are developed from the relative timing between the localized clock skew and the data paths. These constraint relationships are reviewed, and compensating design techniques are discussed.

Economical and ecological criteria for optimal N fertilization are inherently in con¯ict, largely due to lack of precise predictions of nitrogen availability as a function of agronomic practice and weather conditions. This problem is particularly pronounced in organic farming, where plant N supply depends on microbial mineralization of organic N such as`green manure'. In the present paper, N dynamics after incorporation of a mixture of a green manure material (undersown white clover) and barley straw was investigated in laboratory and ®eld experiments. Nitrogen¯ows in the soil±plant system were further analyzed with simulation models (COUP: heat and water transport model, SOILN_NO: soil nitrogen model). Our laboratory experiments showed that the incorporation of a mixture of N-rich white clover material and N-poor barley straw created a transient accumulation of clover derived inorganic N during the ®rst period. Thereafter, microbial N demand during straw C utilization resulted in net immobilization of most of the clover derived inorganic N. As a consequence, the synchronization between net N mineralization and plant N uptake would be better by spring than autumn incorporation. This was largely con®rmed both by measurements and simulations. However, the expected bene®t of spring incorporation (ploughing) was counteracted by a large loss (36%) of clover material due to freeze/thaw damage and subsequent surface runoff during the winter. Such winter loss is likely to be a rare phenomenon, however.

In this paper, a novel adaptive interval type-2 fuzzy sliding mode control (AITFSMC) is proposed to handle high level uncertainties facing the fuzzy logic controller (FLC) in dynamic fractional order chaotic systems such as uncertainties in inputs to the FLC, uncertainties in control outputs, linguistic uncertainties and uncertainties associated with the noisy training data. Based on the learning algorithm combining Lyapunov approach and sliding mode control, free parameters of the AITSMC can be tuned on line by output feedback control law and adaptive law to synchronize two different uncertain fractional order chaotic systems. Meanwhile, the chattering phenomena in the control efforts can be reduced. During the design procedure, not only the stability and robustness can be guaranteed but also the external disturbance on the synchronization error can be attenuated. The numerical simulation is performed to illustrate the effectiveness of the proposed control strategy.

This paper analyzes a methodology to evaluate the efficiency of different network configurations and associated planning parameters for delivering DVB-T2 services to fixed and portable receivers, based on theoretical SFN networks. The impact of some of the parameters and calculation algorithms on the final coverage percentage values for different SFN network architectures has been studied from simulations. The results have shown that the synchronization strategy and the signal combination method have a relevant impact on the final coverage percents within the service area both for portable and fixed reception.

We deployed 72 sensors of 10 modalities in 15 wireless and wired networked sensor systems in the environment, in objects, and on the body to create a sensor-rich environment for the machine recognition of human activities. We acquired data from 12 subjects performing morning activities, yielding over 25 hours of sensor data. We report the number of activity occurrences observed during post-processing, and estimate that over 13000 and 14000 object and environment interactions occurred. We describe the networked sensor setup and the methodology for data acquisition, synchronization and curation. We report on the challenges and outline lessons learned and best practice for similar large scale deployments of heterogeneous networked sensor systems. We evaluate data acquisition quality for on-body and object integrated wireless sensors; there is less than 2.5% packet loss after tuning. We outline our use of the dataset to develop new sensor network self-organization principles and machine learning techniques for activity recognition in opportunistic sensor configurations. Eventually this dataset will be made public.

Synchronization behavior of electroencephalographic (EEG) signals is important for decoding information processing in the human brain. Modern multichannel EEG allows a transition from traditional measurements of synchronization in pairs of EEG signals to whole-brain synchronization maps. The latter can be based on bivariate measures (BM) via averaging over pair-wise values or, alternatively, on multivariate measures (MM), which directly ascribe a single value to the synchronization in a group. In order to compare BM versus MM, we applied nine different estimators to simulated multivariate time series with known parameters and to real EEGs. We found widespread correlations between BM and MM, which were almost frequency-independent for all the measures except coherence. The analysis of the behavior of synchronization measures in simulated settings with variable coupling strength, connection probability, and parameter mismatch showed that some of them, including S-estimator, S-Renyi, omega, and coherence, are more sensitive to linear interdependences, while others, like mutual information and phase locking value, are more responsive to nonlinear effects. One must consider these properties together with the fact that MM are computationally less expensive and, therefore, more efficient for the large-scale data sets than BM while choosing a synchronization measure for EEG analysis.

Objective: The aim of the present study was to analyze in detail the relationship of two newly introduced measures, related to the Beta and Gamma EEG bands during REM sleep, with Delta and Sigma activity at REM sleep onset and REM sleep end, in order to understand their eventual role in the sleep modulation mechanism.

Ultrahigh storage densities of up to 1 Tb/in. 2 or more can be achieved by using local-probe techniques to write, read back, and erase data in very thin polymer films. The thermomechanical scanning-probe-based data-storage concept called Millipede combines ultrahigh density, small form factor, and high data rate. After illustrating the principles of operation of the Millipede, a channel model for the analysis of the readback process is introduced, and analytical results are compared with experimental data. Furthermore, the arrangement of data-storage fields as well as dedicated fields for servo and timing control is discussed, and system aspects related to the readback process, multiplexing, synchronization, and position-error-signal generation for tracking are introduced. Finally, the application of ( ) modulation coding as a means to further increase areal density is presented, and the effect on the user data rates discussed.

We examined how people synchronize their leg movements while walking side-by-side on a treadmill. Walker pairs were either instructed to synchronize their steps in in-phase or in antiphase or received no coordination instructions. Frequency and phase analysis revealed that instructed in-phase and antiphase coordination were equally stable and independent of walking speed and the difference in individually preferred stride frequencies. Without instruction we found episodes of frequency locking in three pairs and episodes of phase locking in four pairs, albeit not always at (or near) 0 • or 180 • . Again, we found no difference in the stability of in-phase and antiphase coordination and no systematic effects of walking speed and the difference in individually preferred stride frequencies. These results suggest that the Haken-Kelso-Bunz model for rhythmic interlimb coordination does not apply to interpersonal coordination during gait in a straightforward manner. When the typically involved parameter constraints are relaxed, however, this model may largely account for the observed dynamical characteristics.

We consider a single server queueing system with generally distributed synchronized services. More specifically, customers arrive according to a Poisson process and there is a single server that provides service, if there is at least one customer present in the system. Upon the initialization of a service, all present customers start to get service simultaneously. We consider the gated version of the model, that is, customers who arrive during a service time do not receive service immediately but wait for the beginning of the next service time. At service completion epochs, all served customers decide simultaneously and independently whether they will leave the system or stay for another service. The probability that a served customer gets another service is the same for all customers.

We investigate frame synchronization algorithms for direct detection multi-pulse pulse position modulation (MPPM) optical communication systems. The optimal rules (in a maximum likelihood sense) are derived, approximations to them that are computationally easier to implement are identified, and upper bounds on the synchronization probability are obtained. It is seen that the high SNR rules have a performance nearly equal to that of the ML rules, but provide a significant performance improvement over the simple correlation rules and are virtually as simple to implement for a wide range of signal energies. We also address the problem of designing periodic MPPM synchronization sequences with good autocorrelation properties, based on a maximum, worst case, peak-to-sidelobe distance criterion. Upper bounds on the peak-to-sidelobe distance for such sequences are derived, and a few sequences, generated by computer simulations, for different synchronization sequence lengths are given.

At the core of the development of "Smart Transmission Grids" is the design, implementation, and testing of synchronized phasor measurement data applications that can supplement Wide-Area Monitoring, Protection, and Control Systems (WAMPAC). Nevertheless, the development of new PMU data-based WAMPAC applications has been relatively slow. The great potential of WAMPAC systems is being limited by this, and efforts are needed so that new applications can be developed. The slow rate of development of these applications is strongly related to, among other factors, the application development approach used. This article starts by discussing the needs and approaches for developing WAMPAC applications that exploit synchronized phasor measurements, and illustrates how one of these approaches has been achieved. A preliminary work carried out to develop and implement a Smart Transmission System Laboratory (SmarTS Lab), a hardware and softwarebased system for developing and analyzing "Smart Transmission Grids" paradigms and applications for WAMPAC systems, are described. The laboratory's conceptual architecture and hardware and software implementation are presented, and some of its components are described. Finally, the article illustrates proofof-concept examples of how PMU data-based applications can be developed.

Introduction: Detection and subsequent correction of sensorimotor timing errors are fundamental to adaptive behavior. Using scalp-recorded event-related potentials (ERPs), we sought to find ERP components that are predictive of error correction performance during rhythmic movements.
Method: Healthy right-handed participants were asked to synchronize their finger taps to a regular tone sequence (every 600 ms), while EEG data were continuously recorded. Data from 15 participants were analyzed. Occasional irregularities were built into stimulus presentation timing: 90 ms before (advances: negative shift) or after (delays: positive shift) the expected time point. A tapping condition alternated with a listening condition in which identical stimulus sequence was presented but participants did not tap.
Results: Behavioral error correction was observed immediately following a shift, with a degree of over-correction with positive shifts. Our stimulus-locked ERP data analysis revealed, 1) increased auditory N1 amplitude for the positive shift condition and decreased auditory N1 modulation for the negative shift condition; and 2) a second enhanced negativity (N2) in the tapping positive condition, compared with the tapping negative condition. In response-locked epochs, we observed a CNV (contingent negative variation)-like negativity with earlier latency
in the tapping negative condition compared with the tapping positive condition. This CNV-like negativity peaked at around the onset of subsequent tapping, with the earlier the peak, the better the error correction performance with the negative shifts while the later the peak, the better the error correction performance with the positive shifts.
Discussion: This study showed that the CNV-like negativity was associated with the error correction performance during our sensorimotor synchronization study. Auditory N1 and N2 were differentially involved in negative vs. positive error correction. However, we did not find evidence for their involvement in behavioral error correction. Overall, our study provides the basis from which further research on the role of the CNV in perceptual and motor timing can be developed.

Objective of this study was to investigate the synchronization between low frequency breathing patterns and respiratory sinus arrhythmia (RSA) of heart rate during guided recitation of poetry, i.e. recitation of hexameter verse from ancient Greek literature performed in a therapeutic setting. 20 healthy volunteers performed three different types of exercises with respect to a cross-sectional comparison: recitation of hexameter verse, controlled breathing and spontaneous breathing. Each exercise was divided into three successive measurements: a 15-minute baseline measurement (S1), 20 minutes of exercise and a 15-minute effect measurement (S2). Breathing patterns and RSA were derived from respiratory traces and electrocardiograms, respectively, which were recorded simultaneously using an ambulatory device. The synchronization was then quantified by the index γ which has been adopted from the analysis of weakly coupled chaotic oscillators. During recitation of hexameter verse γ was high, indicating prominent cardiorespiratory synchronization.