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1
Koch, Walter V. von (Walter Victor von) 1973. "Heterogeneous synchronization". Thesis, Massachusetts Institute of Technology, 1998. http://hdl.handle.net/1721.1/46232.
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Thesis (S.B. and M.Eng.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 1998.Includes bibliographical references (p. 59-60).
by Walter V. vonKotch.
S.B.and M.Eng.
2
Chen, Liubo. "Concurrent programming : thread-based synchronization versus job-based synchronization /". Search for this dissertation online, 2005. http://wwwlib.umi.com/cr/ksu/main.
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3
Sreeram, Jaswanth. "Optimistic semantic synchronization". Diss., Georgia Institute of Technology, 2011. http://hdl.handle.net/1853/42802.
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Within the last decade multi-core processors have become increasingly commonplace with the
power and performance demands of modern real-world programs acting to accelerate this trend. The
rapid advancements in designing and adoption of such architectures mean that there is a serious need
for programming models that allow the development of correct parallel programs that execute
efficiently on these processors. A principle problem in this regard is that of efficiently synchronizing
concurrent accesses to shared memory. Traditional solutions to this problem are either inefficient but
provide programmability (coarse-grained locks) or are efficient but are not composable and very hard
to program and verify (fine-grained locks). Optimistic Transactional Memory systems provide many of
the composability and programmabillity advantages of coarse-grained locks and good theoretical
scaling but several studies have found that their performance in practice for many programs remains
quite poor primarily because of the high overheads of providing safe optimism. Moreover current
transactional memory models remain rigid - they are not suited for expressing some of the complex
thread interactions that are prevalent in modern parallel programs. Moreover, the synchronization
achieved by these transactional memory systems is at the physical or memory level.
This thesis advocates a position that memory synchronization problem for threads should be
modeled and solved in terms of synchronization of underlying program values which have semantics
associated with them. It presents optimistic synchronization techniques that address the semantic
synchronization requirements of a parallel program instead.
These techniques include methods to 1) enable optimistic transactions to recover from
expensive sharing conflicts without discarding all the work made possible by the optimism 2) enable a
hybrid pessimistic-optimistic form of concurrency control that lowers overheads 3) make
synchronization value-aware and semantics-aware 4) enable finer grained consistency rules (than
allowed by traditional optimistic TM models) therefore avoiding conflicts that do not enforce any
semantic property required by the program. In addition to improving the expressibility of specific
synchronization idioms all these techniques are also effective in improving parallel performance. This
thesis formulates these techniques in terms of their purpose, the extensions to the language, the
compiler as well as to the concurrency control runtime necessary to implement them. It also briefly
presents an experimental evaluation of each of them on a variety of modern parallel workloads. These
experiments show that these techniques significantly improve parallel performance and scalability over
programs using state-of-the-art optimistic synchronization methods.
4
Wedge, Daniel John. "Video sequence synchronization". University of Western Australia. School of Computer Science and Software Engineering, 2008. http://theses.library.uwa.edu.au/adt-WU2008.0084.
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[Truncated abstract] Video sequence synchronization is necessary for any computer vision application that integrates data from multiple simultaneously recorded video sequences. With the increased availability of video cameras as either dedicated devices, or as components within digital cameras or mobile phones, a large volume of video data is available as input for a growing range of computer vision applications that process multiple video sequences. To ensure that the output of these applications is correct, accurate video sequence synchronization is essential. Whilst hardware synchronization methods can embed timestamps into each sequence on-the-fly, they require specialized hardware and it is necessary to set up the camera network in advance. On the other hand, computer vision-based software synchronization algorithms can be used to post-process video sequences recorded by cameras that are not networked, such as common consumer hand-held video cameras or cameras embedded in mobile phones, or to synchronize historical videos for which hardware synchronization was not possible. The current state-of-the-art software algorithms vary in their input and output requirements and camera configuration assumptions. ... Next, I describe an approach that synchronizes two video sequences where an object exhibits ballistic motions. Given the epipolar geometry relating the two cameras and the imaged ballistic trajectory of an object, the algorithm uses a novel iterative approach that exploits object motion to rapidly determine pairs of temporally corresponding frames. This algorithm accurately synchronizes videos recorded at different frame rates and takes few iterations to converge to sub-frame accuracy. Whereas the method presented by the first algorithm integrates tracking data from all frames to synchronize the sequences as a whole, this algorithm recovers the synchronization by locating pairs of temporally corresponding frames in each sequence. Finally, I introduce an algorithm for synchronizing two video sequences recorded by stationary cameras with unknown epipolar geometry. This approach is unique in that it recovers both the frame rate ratio and the frame offset of the two sequences by finding matching space-time interest points that represent events in each sequence; the algorithm does not require object tracking. RANSAC-based approaches that take a set of putatively matching interest points and recover either a homography or a fundamental matrix relating a pair of still images are well known. This algorithm extends these techniques using space-time interest points in place of spatial features, and uses nested instances of RANSAC to also recover the frame rate ratio and frame offset of a pair of video sequences. In this thesis, it is demonstrated that each of the above algorithms can accurately recover the frame rate ratio and frame offset of a range of real video sequences. Each algorithm makes a contribution to the body of video sequence synchronization literature, and it is shown that the synchronization problem can be solved using a range of approaches.
5
Lamont, Robert W. "Direct fire synchronization". Thesis, Monterey, California. Naval Postgraduate School, 1992. http://hdl.handle.net/10945/23644.
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Approved for public release; distribution is unlimitedThis thesis analyzes defense in sector missions adapted from the National Training Center and conducted with the Janus(A) high resolution combat model to check for relationships which influence direct fire synchronization. This analysis should enhance the monitoring of unit performances in the area of concentration of massing of fires consistent with the commander's intent. The combat fighting vehicle, which combines the characteristics of mobility with high volumes of firepower, dominates the desert battlefield and is the focus of this study. Graphical methods and analytic techniques are developed the describe the battle in terms of direct fire synchronization and a mission measure of effectiveness (MOE). This research is being conducted under the E.S. Army's Battle Enhanced Analysis methodologies (BEAM) study, which is developing objective doctrinal AirLand battle measures and visual displays to enhance training analysis. The thesis also describes the training environment of the NTC, defense in sector doctrine for both the U.S. Army and the U.S. Marine Corps with emphasis on asymmetries, and threat offensive doctrine
6
James, Calvin L. "Optimum Symbol Synchronization". International Foundation for Telemetering, 1994. http://hdl.handle.net/10150/611676.
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International Telemetering Conference Proceedings / October 17-20, 1994 / Town & Country Hotel and Conference Center, San Diego, CaliforniaAlthough most closed-loop synchronizers employ maximum likelihood estimators for symbol value decisions, in general, their symbol timing estimates are not optimum. It would seem only natural that an optimum timing estimator would choose interval partitions based on maximizing the observed sample signal-to-noise ratio. The symbol synchronizer described below achieves optimum performance when decisions on present symbol values are based on current and previously-received symbol samples. This procedure attempts to reestablish the interval independence criterion, thereby reducing timing estimator variance. The realization presented is motivated by an open-loop maximum a posteriori (MAP) structure analysis.
7
Malekighaleabdolreza, Mahmoud. "Distributed Device Synchronization". Thesis, Uppsala universitet, Institutionen för informationsteknologi, 2018. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-372071.
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Generally, synchronization in Wireless Sensor Networks (WSN), allows successful and accurate communication between nodes to occur. Each node in WSN runs independently and have its own clock which can drift from the other device’s clock. Many application in WSN requires a common notion of time between nodes in order to be able to provide a reliable performance and operation. The focus of this research is to study whether a sufficient synchronization accuracy between nodes in WSN using bluetooth mesh communication can be achieved, that would allow us to turn on and off LEDs on distributed devices in such way that we create an LCD-like behavior with 50Hz (20ms) resolution. We use NRF52840-PDK devices in this thesis and for synchronization purpose, we are using FTSP and RBS+FTSP synchronization protocols. The RBS+FTSP protocol is the combination of both RBS and FTSP protocols which have the benefits of both protocols and improves the performance of the synchronization in our use case, this protocol is explained more in detail in later sections (see chapter 2.1.3 ). Based on the results that we have it is possible to achieve low-ms synchronization accuracy using the bluetooth mesh communication technology using FTSP and RBS+FTSP protocols. The synchronization resolution that we achieved using bluetooth mesh technology and our synchronization protocols were below 10ms which are good enough to accomplish the required 50Hz (20ms) resolution of our LCD-like screen with distributed devices. The same method can also be used to perform synchronization between nodes for various other actuation and sensing purposes in wireless sensor networks.
8
Deconda, Keerthi. "Fault tolerant pulse synchronization". Thesis, [College Station, Tex. : Texas A&M University, 2008. http://hdl.handle.net/1969.1/ETD-TAMU-2331.
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9
Pereira, Tiago. "Synchronization in active networks". [S.l.] : [s.n.], 2007. http://opus.kobv.de/ubp/volltexte/2007/1434.
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10
Shao, Junming. "Synchronization Inspired Data Mining". Diss., lmu, 2011. http://nbn-resolving.de/urn:nbn:de:bvb:19-137356.
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11
Pereira, da Silva Tiago. "Synchronization in active networks". Phd thesis, Universität Potsdam, 2007. http://opus.kobv.de/ubp/volltexte/2007/1434/.
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In nature one commonly finds interacting complex oscillators which by the coupling scheme form small and large networks, e.g. neural networks. Surprisingly, the oscillators can synchronize, still preserving the complex behavior. Synchronization is a fundamental
phenomenon in coupled nonlinear oscillators.
Synchronization can be enhanced at different levels, that is, the constraints on which the synchronization appears. Those can be in the trajectory amplitude, requiring the amplitudes of both oscillators to be equal, giving place to complete synchronization. Conversely, the constraint could also be in a function of the trajectory, e.g. the phase, giving place to phase synchronization (PS). In this case, one requires the phase difference between both oscillators to be finite for all times, while the trajectory amplitude may be uncorrelated. The study of PS has shown its relevance to important technological problems, e.g. communication, collective behavior in neural networks, pattern formation, Parkinson disease, epilepsy, as well as behavioral activities. It has been reported that it mediates processes of information transmission and collective behavior in neural and active networks and communication processes in the Human brain.
In this work, we have pursed a general way to analyze the onset of PS in small and large networks. Firstly, we have analyzed many phase coordinates for compact attractors. We have shown that for a broad class of attractors the PS phenomenon is invariant under the phase definition.
Our method enables to state about the existence of phase synchronization in coupled chaotic oscillators without having to measure the phase. This is done by observing the oscillators at special times, and analyzing whether this set of points is localized. We have show that this approach is fruitful to analyze the onset of phase synchronization in chaotic attractors whose phases are not well defined, as well as, in networks of non-identical spiking/bursting neurons connected by chemical synapses. Moreover, we have also related the synchronization and the information transmission through the conditional observations. In particular, we have found that inside a network clusters may appear. These can be used to transmit more than one information, which provides a multi-processing of information. Furthermore, These clusters provide a multichannel communication, that is, one can integrate a large number of neurons into a single communication system, and information can arrive simultaneously at different places of the network.In oder Natur sind interagierende komplexe Oszillatoren, die Netzwerke bilden, häufig anzutreffen. Erstaunlich ist, dass sich diese Oszillatoren synchronisieren, ohne ihr eigenes komplexes Verhalten zu verlieren. Diese Fähigkeit zur Synchronisation ist eine wesentliche Eigenschaft von gekoppelten nichtlinearen Oszillatoren. Die Fähigkeit zur Synchronisation kann auf unterschiedliche Weise durch Eingriff in die Bedingungen, die zur Synchronisation führen, verbessert werden. Es kann sowohl eine Synchronisation der Amplituden als auch der Phasen stattfinden bzw. erzwungen werden. Insbesondere Phase Synchronisation über die Phase (PS) hat sich in den wichtigen Bereichen der Technik, Kommunikation, Soziologie und Neurologie als Modellierungsgrundlage bewiesen. Bekannte Beispiele aus der Neurologie sind Parkinson und Epilepsie. In der vorliegenden Arbeit haben wir nach einem verallgemeinerten Weg gesucht, das Phänomen der PS in Netzwerken analysieren zu können. Zuerst haben wir viele Phasendefinitionen für einfache Attraktoren (Oszillatoren mit definierten Phaseneigenschaften) untersucht und festgestellt, dass das Phänomen der PS unabhängig von der Definition der Phase ist. Als nächstes haben wir begonnen, die maximale Abweichungen abzuschätzen, bei der die Synchronisation für bei einer gegebene Phase nicht verlorengeht. Abschließend haben wir eine Methode entwickelt, mittels derer Synchronisation in chaotischen System festgestellt werden kann, ohne die Phase selbst messen zu müssen. Dazu wird zu geeigneten Zeitpunkten der Zustandsraum untersucht. Wir können zeigen, dass mittels dieser Methode in chaotisch Systemen sowohl die Grössenordnung der Synchronisation als auch die Bereiche, in denen Synchronisation stattfindet, untersucht werden können. Dabei kann festgestellt werden, dass der Grad der Synchronisation mit der Menge an Information in Beziehung steht, die an verschieden Stellen eines Netzwerks gleichzeitig übermittelt wird. Dies kann zur Modellierung der Informationsübertragung über die Synapsen im Gehirn verwendet werden.
12
Allefeld, Carsten, e Jürgen Kurths. "Testing for phase synchronization". Universität Potsdam, 2004. http://opus.kobv.de/ubp/volltexte/2008/2009/.
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We present different tests for phase synchronization which improve the procedures currently used in the literature. This is accomplished by using a two-samples test setup and by utilizing insights and methods from directional statistics and bootstrap theory. The tests differ in the generality of the situation in which they can be applied as well as in their complexity, including computational cost. A modification of the resampling technique of the bootstrap is introduced, making it possible to fully utilize data from time series.
13
Beek, Jaap van de. "Estimation of synchronization parameters". Licentiate thesis, Luleå tekniska universitet, Signaler och system, 1996. http://urn.kb.se/resolve?urn=urn:nbn:se:ltu:diva-16971.
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This thesis deals with the estimation of synchronization parameters in {Orthogonal Frequency Division Multiplexing} (OFDM) communication systems and in active ultrasonic measuring systems. Estimation methods for the timing and frequency offset and for the attenuation taps of the frequency selective channel are presented and investigated.In OFDM communication systems the estimation of the timing offset of the transmitted data frame is one important parameter. This offset provides the receiver with a means of synchronizing its sampling clock to that of the transmitter. A second important parameter is the offset in the carrier frequency used by the receiver to demodulate the received signal.For OFDM systems using a cyclic prefix, the joint {Maximum Likelihood} (ML) estimation of the timing and carrier frequency offset is introduced. The redundancy introduced by the prefix is exploited optimally. This novel method is derived for a non-dispersive channel. Its performance, however, is also evaluated for a frequency-selective Rayleigh-fading radio channel. Time dispersion causes an irreducible error floor in this estimator's performance. This error floor is the limiting factor for the applicability of the timing estimator. Depending on the requirements, it may be used in either an acquisition or a tracking mode. For the frequency estimator the error floor is low enough to allow for stable frequency tracking.A low-complex variant of the timing offset estimator is presented allowing a simple implementation. This is the ML estimator, given a 2-bit representation of the received signal as the sufficient statistics. Its performance is evaluated for a frequency-selective Rayleigh-fading radio channel and for a twisted-pair copper channel. Simulations show this estimator to have a similar error floor as the full resolution ML estimator.The problem of estimating the propagation time of a signal is also of interest in active pulse echo systems, such as are used in, {\it e.g.}, radar, medical imaging, and geophysics. The {Minimum Mean Squared Error} (MMSE) estimator of arrival time is derived and investigated for an active airborne ultrasound measurement system. Besides performing better than the conventional {\it Maximum a Posteriori} (MAP) estimator, this method can be used to develop different estimators in situations where the system Signal to Noise Ratio (SNR) is unknown.Coherent multi-amplitude OFDM receivers generally need to compensate for a frequency selective channel in order to detect transmitted data symbols reliably. For this purpose, a channel equalizer needs to be fed estimates of the subchannel attenuations.The linear MMSE estimator of these attenuations is presented. Of all linear estimators, this estimator optimally makes use of the frequency correlation between the subchannel attenuations. Low-complex modified estimators are proposed and investigated. The proposed modifications cause an irreducible error floor for this estimator's performance, but simulations show that for SNR values up to 20~dB, the improvement of a modified estimator compared to the Least Squares (LS) estimator is at least 3~dB.Godkänd; 1996; 20080328 (ysko)
14
Wang, Sharon X. "Simulation of chaos synchronization". Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1998. http://www.collectionscanada.ca/obj/s4/f2/dsk2/tape15/PQDD_0006/MQ32521.pdf.
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Pita, A. A. C. "Synchronization in baroclinic systems". Thesis, University of Oxford, 2008. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.489417.
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In recent years, the study of synchronization phenomena in nonlinear systems has made a number of significant advances in various areas of physics, engineering and the life sciences. Ideas of chaos synchronization have been used recently in some atmospheric phenomena as an attempt to better understand certain kinds of cyclic behaviour and teleconnection patterns, and at least some have shown promising results.
16
RIBEIRO, MARCELO PEIXOTO. "SYNCHRONIZATION IN COMMUNICATION SYSTEMS". PONTIFÍCIA UNIVERSIDADE CATÓLICA DO RIO DE JANEIRO, 1990. http://www.maxwell.vrac.puc-rio.br/Busca_etds.php?strSecao=resultado&nrSeq=9258@1.
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O presente texto aborda aspectos do problema de
sincronização em sistemas de telecomunicações, com
enfoque
nas funções de demodulação síncrona, regeneração,
multiplexação/demultiplexação (TDM) e comutação (digital).
São tratados os métodos de obtenção de referência de
portadora e de referência de relógio, os recursos de
malha de amarração de fase (PLL) e de memória elástica.
O objetivo final consiste na descrição dos métodos de
sincronização de rede, nas modalidades plesiócrona (e
plesiócrona com justificação), mestre-escravo e
sincronização mútua.
As subredes de sincronização são analisadas em termos de
topologia, segurança, determinação de freqüência e fases
de operação e de compensação de defasagens na transmissão.
A apresentação é feita em termos de um texto didático
para
a descrição dos problemas e de suas soluções.This text deals with aspects of synchronization in telecommunication systems, with emphasis on the operational functions of synchronous demodulation, signal regeneration, multiplexing/demultiplexing (TDM) and digital switching. The methods of carrier recovery, clock recovery, phase locked loop and elastic store are presented. The final goal consists on the description of network synchronization methods, in the plesiochronous (and plesiochronous with justification), master-slave and mutual synchronization modalities. The synchronization subnetworks are analised in terms of topology, safety, operation frequency and phases, and transmission phase delay compensation. The presentation is made in a didactical way, describing the problems and their possible solutions.
17
Harding, Rachael S. M. Massachusetts Institute of Technology. "Synchronization on nulticore architectures". Thesis, Massachusetts Institute of Technology, 2014. http://hdl.handle.net/1721.1/87944.
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Thesis: S.M., Massachusetts Institute of Technology, Department of Electrical Engineering and Computer Science, 2014.Cataloged from PDF version of thesis.
Includes bibliographical references (pages 53-55).
The rise of multicore computing has made synchronization necessary to overcome the challenge of sharing data between multiple threads. Locks are critical synchronization primitives for maintaining data integrity and preventing race conditions in multithreaded applications. This thesis explores the lock design space. We propose a hardware lock implementation, called the lock arbiter, which reduces lock latency while minimizing hardware overheads and maintaining high levels of fairness between threads. We evaluate our mechanism against state-of-the-art software lock algorithms and find that our mechanism has comparable performance and fairness.
by Rachael Harding.
S.M.
18
Terry, John R. "Synchronization of coupled systems". Thesis, University of Surrey, 2000. http://epubs.surrey.ac.uk/844090/.
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Synchronization of chaos in coupled systems of ordinary differential equations is an area of mathematics which has attracted much attention in recent years, in particular for the potential technological applications such systems have in engineering and industry. The motivation for this research was to understand mathematically, synchronization observed in systems of two and three solid state lasers studied by collaborators at the Georgia Institute of Technology. The main objectives of this thesis are to understand more clearly some of the dynamical phenomena associated with the synchronization of chaos, and to develop new techniques for the analysis of dynamical systems with symmetry; with a view to applying these techniques to models of solid state laser systems and other applications. First we introduce the main ideas of chaotic synchronization and some useful tools for the analysis of dynamical systems with symmetry. We then introduce a model for a solid state Nd:YAG laser and examine the types of dynamics which may be exhibited. Subsequently we look at systems of two and three coupled solid state lasers and examine the onset of synchronization in such systems, both in a fully symmetric system and in the case of two coupled lasers, the case of broken symmetry. We then contrast these results with those of a modified Rossler system and observe similar results in both cases. We examine how chaotic systems may be used for communication purposes and develop a new scheme for the communication of a signal using the synchronization of chaos. Finally we introduce a new definition of attractor and using topological and measure theoretic properties of sets, we reexamine the concepts of basin riddling and are able in certain situations to determine the presence or otherwise of riddling.
19
Fietkiewicz, Chris. "Synchronization of Hypoglossal Motoneurons". Case Western Reserve University School of Graduate Studies / OhioLINK, 2010. http://rave.ohiolink.edu/etdc/view?acc_num=case1279714872.
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20
Baek, Seung-Jong. "Synchronization in chaotic systems". College Park, Md.: University of Maryland, 2007. http://hdl.handle.net/1903/7728.
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Thesis (Ph. D.) -- University of Maryland, College Park, 2007.Thesis research directed by: Dept. of Electrical and Computer Engineering. Title from t.p. of PDF. Includes bibliographical references. Published by UMI Dissertation Services, Ann Arbor, Mich. Also available in paper.
21
Aihara, Ikkyu. "Synchronization of Calling Frogs". 京都大学 (Kyoto University), 2011. http://hdl.handle.net/2433/142353.
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Selingardi, Matias Fernanda. "Anticipated synchronization in neuronal circuits". Doctoral thesis, Universitat de les Illes Balears, 2014. http://hdl.handle.net/10803/145929.
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Anticipated Synchronization (AS) is a form of synchronization that occurs when a unidirectional influence is transmitted from an emitter to a receiver, but the receiver system leads the emitter in time. This counterintuitive phenomenon can be a stable solution of two dynamical systems coupled in a master-slave configuration when the slave is subject to a negative delayed self-feedback. Many examples of AS dynamics have been found in different systems, however, theoretical and experimental evidence for it in the brain has been lacking. In this thesis work we investigate the existence of AS in neuronal circuits when the delayed feedback is replaced by an inhibitory loop mediated by chemical synapses. At the neuronal level, we show the existence of AS in 3-neuron or 3-neuron-populations microcircuits, where the self-feedback is provided either by an interneuron or by a subpopulation of inhibitory neurons. A smooth transition from delayed synchronization (DS) to AS typically occurs when the inhibitory synaptic conductance is increased. The phenomenon is shown to be robust for a wide range of model parameters within a physiological range. The role of spiketiming- dependent plasticity in DS-AS transitions is also investigated. The results obtained from the model are compared with those obtained experimentally in monkeys performing certain cognitive tasks. In some cases a dominant directional influence from one cortical area to another is accompanied by either a negative or a positive time delay. We present a model for AS between two brain regions and compare its results to the experimental data, obtaining an excellent agreement.La sincronización anticipada (SA) es una forma de sincronización que se produce cuando una influencia unidireccional se transmite desde un emisor a un receptor, pero el sistema receptor adelanta al emisor en el tiempo. Este fenómeno, contrario a la intuición, puede ser una solución estable de dos sistemas dinámicos acoplados en una configuración maestro – esclavo cuando el esclavo está sujeto a una retroalimentación negativa retardada. Hay muchos ejemplos de SA que se han encontrado en diferentes sistemas, sin embargo, no existe evidencia ni teórica ni experimental de que ocurra en el cerebro. En este trabajo de tesis se investiga la existencia la SA en circuitos neuronales cuando la realimentación retardada se sustituye por un bucle inhibitorio mediado por sinapsis químicas. A nivel neuronal, se muestra la existencia de SA en circuitos de 3 neuronas o 3 poblaciones de neuronas, donde la retroalimentación la proporciona una interneurona o una subpoblación de neuronas inhibitorias. Una transición de sincronización retrasada (SR) a SA se produce suavemente cuando se incrementa la conductancia sináptica inhibitoria. Se encuentra que el fenómeno es robusto para una amplio espectro de parámetros del modelo dentro del rango fisiológico. También se investiga el papel de la plasticidad neuronal en la transición SR-SA. Los resultados obtenidos a partir del modelo se comparan con los obtenidos experimentalmente en monos cuando realizan ciertas tareas cognitivas. En algunos casos, una influencia direccional dominante de un área cortical a otra se acompaña de un retardo que puede ser negativo o positivo. Se presenta un modelo para las relaciones entre dos regiones corticales del cerebro y se compararan los resultados numéricos con los datos experimentales, obteniendo un excelente acuerdo.
23
Campana, Riccardo. "NB-IoT synchronization procedure analysis". Master's thesis, Alma Mater Studiorum - Università di Bologna, 2021. http://amslaurea.unibo.it/22583/.
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The Third Generation Partnership Project (3GPP), recognizing the importance of IoT, introduced a number of key features to supporting it since Release 13. In particular, since 2017 the so called NB-IoT has been launched, providing progressively improved support for Low Power Wide Area Networks (LPWAN). While terrestrial technologies will play a key role in the provision of the NB-IoT service, satellite networks can have a complementary role thanks to their very wide coverage area and short service deployment time. Within the aforementioned framework, the aim of this thesis is to analyze the feasibility of integrating the NB-IoT technology with satellite communication (SatCom) systems, focusing in particular in the assessment of the downlink synchronization procedure in the NB-IoT SatCom systems. For this reason, this work investigates the issues introduced by the integration between the NB-IoT terrestrial network and Non Terrestrial Networks (NTN). Furthermore, in order to find possible solutions to harmonize their coexistence, the state of the art of the satellite channel effect mitigation techniques is analyzed. After that, the implementation of a MATLAB simulator for the cell synchronization procedure is presented, as a first step for the understanding of the whole NB-IoT procedures.
24
Topaj, Dmitri. "Synchronization transitions in complex systems". Phd thesis, [S.l.] : [s.n.], 2001. http://pub.ub.uni-potsdam.de/2002/0006/topaj.pdf.
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25
Jørgen, Kristoffersen. "Synchronization of pulse-coupled oscillators". Thesis, Norwegian University of Science and Technology, Department of Physics, 2009. http://urn.kb.se/resolve?urn=urn:nbn:no:ntnu:diva-6354.
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Hoefler, Torsten. "Fast Barrier Synchronization for InfiniBand". Universitätsbibliothek Chemnitz, 2006. http://nbn-resolving.de/urn:nbn:de:swb:ch1-200600019.
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Barrier Synchronization is crucial for many parallel systems. This talk introduces different synchronization mechanisms and demonstrates new approaches to leverage special hardware properties of InfiniBand to lower the Barrier latency.
27
Gursan, Hakan Yesari. "Frame Synchronization In Ofdm Systems". Master's thesis, METU, 2005. http://etd.lib.metu.edu.tr/upload/12605782/index.pdf.
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In this thesis, we considered the problem of frame synchronization and channel estimation in Orthogonal Frequency Division Multiplexing (OFDM) systems. Since
framing error may cause severe ISI and may disturb the orthogonality of the subcarriers, frame synchronization must be accomplished at the OFDM receiver. Furthermore, the effects of channel must be compensated to obtain the symbols accurately. We investigated several frame synchronization algorithms including a maximum likelihood (ML) synchronizer which relies on the periodicity induced in the OFDM structure, and a robust synchronizer which uses a special training symbol. These algorithms are evaluated in AWGN and Rayleigh fading multipath channels and performances are compared in terms of percentage of ISI-free synchronization, mean squared error and symbol error rate. The IEEE 802.11a framework is used to compare these algorithms with the standard system which utilizes training symbols dedicated for synchronization. It is shown that an adjustment for the frame start estimates must be done to avoid the effects of the channel delay spread. It is also
pointed that ideal synchronization is not necessary unless symbol boundaries are detected inside an ISI-free region and the error aroused in ISI-free synchronization can be compensated by applying channel estimation and equalization regarding the same symbol boundaries.
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Kaya, Zahit Evren. "Time Synchronization In Measurement Networks". Master's thesis, METU, 2008. http://etd.lib.metu.edu.tr/upload/2/12611585/index.pdf.
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AMR (Automatic Measurement Reading) applications usually require measurement data to be collected from separate locations. In order to combine the data retrieved from separate sources into a meaningful result, all sources should share a common time sense. Therefore, it is necessary to implement a synchronization scheme in measurement networks. In this thesis, a synchronization scheme which combines GPS (Global Positioning System) and two high accuracy WSN (Wireless Sensor Network) time synchronization algorithms will be proposed and evaluated. The synchronization accuracy of the proposed method is compared to the accuracy of NTP (Network Time Protocol) by simulation. This research work is fully supported by the Public Research Grant Committee (KAMAG) of TUBiTAK within the scope of National Power Quality Project of Turkey with the project No: 105G129.
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Sharma, Siddharth. "Clock Synchronization in Decentralized Systems". Thesis, KTH, Skolan för informations- och kommunikationsteknik (ICT), 2012. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-94141.
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Clock synchronization between different entities in a system has been approached using two main methods, decentralized and centralized synchronization. Examples of centralized synchronization include Network Time Protocol (NTP) and the use of Global Positioning System (GPS) as a central clock. The synchronization of clocks in distributed systems is a well-studied and difficult problem. Current solutions possess a significant convergence delay and a non-perfect synchronization window. This thesis approaches the problem of clock synchronization in decentralized systems by analysing and using pulse-coupled oscillator models, like the Kuramoto model and the Mirollo-Strogatz firefly model, while leveraging the knowledge of internode latencies to form a biased gradient overlay topology, and creating a custom firefly synchronization model. The system node coordinates are indicative of internode latencies if they are assigned statically using a latency data set or through a dynamic coordinate protocol, which assigns coordinates according to current internode latencies. The coordinates are then used to create an overlay over the physical topology by having larger number of links with lower internode latency. Neighbours are selected based on an information need basis. Logical time on the nodes is set in sync along with the phase synchronization using fine tuned algorithms to set a common timestamp on each cycle, and to optimize the synchronization window and the convergence time. The results show that the gradient firefly synchronization is efficient in convergence time as well as synchronization window. The protocol works better with a single cluster of nodes as compared to multiple clusters. It is concluded in the thesis that latency aware gradient firefly synchronization protocols can be used per cluster and the performance can be improved further with the incorporation of dynamic coordinate protocols.
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Golfinger, Sergej. "Event-Triggered Control for Synchronization". Thesis, KTH, Reglerteknik, 2012. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-98869.
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The first main part of this thesis presents a novel distributed event-based control strategy for the synchronization of a network consisting of N identical dynamical linear systems. The problem statement can be interpreted as a generalization of a classical event-based consensus problem. Each system updates its control signals according to some triggering conditions based on local information only. Starting with the event-based synchronization with state feedback two different approaches are derived. The trigger functions of the first approach depend on the transfered system states, while the trigger conditions of the second approach depend on the control inputs. The advantages (or otherwise) of both approaches and implementations are discussed. Furthermore, we extend the problem setup to the synchronization with a dynamic output feedback coupling and transfer the both event-based methods to this problem. The novel proposed approaches yields to the general results for the event-based synchronization for linear systems. In the second smaller part we present a new method for the distributed event-based synchronization of Kuramoto oscillators. We assume a uniform Kuramoto model of N all-to-all connected oscillators with different natural frequencies. Throughout the report, simulation results validate and illustrate the proposed theoretical results.
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Li, Li. "Synchronization studies in multimedia communications". Thesis, University of Ottawa (Canada), 1994. http://hdl.handle.net/10393/6531.
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Synchronization is considered as a key issue in distributed multimedia systems. Synchronization problems exist in both multimedia presentational and conversational applications. In a multimedia presentation, two basic synchronization issues are involved: Temporal Presentation Control (TPC) and Simultaneous Real-Time Data Delivery (SRTDD). TPC deals with the ordering of data objects in the presentation. SRTDD refers to simultaneously delivering multimedia data in different data streams belonging to the same time interval. In multimedia conversational applications, e.g., in cooperative applications, coordination control and causal ordering of the events give another synchronization problem. This thesis investigates the synchronization control in the distributed multimedia systems. All the above synchronization issues are covered. The temporal model and a synchronization algorithm for the TPC are proposed, which can support the real-time multimedia teleorchestration when multiple independent information sources are involved. The temporal model handles the relative and imprecise temporal requirements among the data objects in the "fuzzy" presentation scenario, and supports the synchronization dialogue among the independent sources. Thus the synchronization algorithm can be performed in a distributed manner. For the SRTDD control, an entire control architecture is presented which follows the layered communications model. We have introduced the multimedia session management, multimedia segment delivery, etc., to achieve the simultaneous data delivery. The Synchronization Quality of Service (SQoS) parameters are first applied for the SRTDD control over the ATM network. Meanwhile, taking the multimedia joint editing, one of the popular multimedia collaborative applications, as an example, we have developed the coordination control and the causal ordering algorithms for the joint editing session. Then in the second part of this thesis, we have studied the analytical performance modeling for distributed multimedia systems where the synchronization is considered. Stochastic Petri Nets (SPN) are applied to model the different multimedia synchronization systems. We developed a computational algorithm for a class of SPNs, i.e., the LBSPNs (Locally Balanced Stochastic Petri Nets), which have product form solutions. Applying the computational algorithm for LBSPN, the performance analysis of a joint editing system is conducted.
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Kumar, Krishna. "Visible synchronization-based cache coherence". Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1997. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape11/PQDD_0001/MQ44885.pdf.
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Slade, James. "Synchronization of multiple rotating systems". Online access for everyone, 2007. http://www.dissertations.wsu.edu/Thesis/Summer2007/j_slade_072607.pdf.
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Chuang, Y. A. "Clock synchronization across standard networks". Thesis, Swansea University, 1994. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.636255.
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In distributed real-time systems, data are time-dependent and the time notation, which marks the validity of data, is an indispensable component of data. Therefore, setting up a common time base in distributed real-time systems to provide all computers in the system with a consistent view of time inevitably becomes important. Clock synchronization is an approach to establishing such an greed global time base in a system. The aim of work is to investigate clock synchronization in a distributed real-time system. A hybrid synchronization method is adopted in the project. By this means, each computer in the system periodically exchanges time messages with other computers via the existing communication network, and thus knows the clock time of every other computer which participates in the clock synchronization. Then, it applies a synchronization algorithm on the received time data to compute an approximate global time for the system, and finally adjusts its local clock to the computed global time. An approximate global time is thus reached and maintained. In this dissertation, various approaches are studied and compared. A hybrid scheme is proved to be the currently dominant solution to the problem investigated, in that it balances the performance and cost criteria. The fault tolerant averaging algorithm selected for this attempt is discussed and analysed, and its software implementation is described. The design and silicon implementation of the associated VLSI clock synchronization unit device are also introduced. The experiments with clock synchronization on an Ethernet system are presented. The results of the experiments are given and analysed to support the conclusions that the technique developed in this work is feasible and can be used in distributed real-time systems. On this basis, recommendations for further research in clock synchronization are suggested.
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Lundqvist, Emil. "Timing and Synchronization over Ethernet". Thesis, Linköpings universitet, Institutionen för systemteknik, 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-115882.
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In this thesis an investigation will be done on how time and frequency can be synchronized over Ethernet with help of Precision Time Protocol and Synchronous Ethernet. The goal is to achieve a high accuracy in the synchronization when a topology of 10 cascaded nodes is used. Different approaches may be used when implementing Precision Time Protocol for synchronization. They will be investigated and the best approach for a good accuracy will be proposed. Another question that this thesis will cover is how to recover a radio frequency, a multiple of 3.84 MHz from Ethernets 10.3125 GHz. By using hardware support for the timestamps and transparent clocks in the forwarding nodes the best accuracy is achieved for the time and phase synchronization. Combining this with Synchronous Ethernet for frequency synchronization, to get a traceable clock through the system, will lead to the best result. The total error does not need to be greater than 1.46~ns if the asymmetry in the medium is neglected and a welldesigned PCS and FIFO are used. Recovering the radio frequency from Ethernet is done by using the highest common frequency, either an integer phase locked loop or a fractional phase locked loop can be used. The fractional phase locked loop will give a better result but will contribute with spurs that the integer phase locked loop does not.
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Cairns, David Edward. "Synchronization in dynamic neural networks". Thesis, University of Stirling, 1993. http://hdl.handle.net/1893/21611.
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This thesis is concerned with the function and implementation of synchronization in networks of oscillators. Evidence for the existence of synchronization in cortex is reviewed and a suitable architecture for exhibiting synchronization is defined. A number of factors which affect the performance of synchronization in networks of laterally coupled oscillators are investigated. It is shown that altering the strength of the lateral connections between nodes and altering the connective scope of a network can be used to improve synchronization performance. It is also shown that complete connective scope is not required for global synchrony to occur. The effects of noise on synchronization performance are also investigated and it is shown that where an oscillator network is able to synchronize effectively, it will also be robust to a moderate level of noise in the lateral connections. Where a particular oscillator model shows poor synchronization performance, it is shown that noise in the lateral connections is capable of improving synchronization performance. A number of applications of synchronizing oscillator networks are investigated. The use of synchronized oscillations to encode global binding information is investigated and the relationship between the form of grouping obtained and connective scope is discussed. The potential for using learning in synchronizing oscillator networks is illustrated and an investigation is made into the possibility of maintaining multiple phases in a network of synchronizing oscillators. It is concluded from these investigations that it is difficult to maintain multiple phases in the network architecture used throughout this thesis and a modified architecture capable of producing the required behaviour is demonstrated.
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Kim, Inwoong. "SYNCHRONIZATION IN ADVANCED OPTICAL COMMUNICATIONS". Doctoral diss., University of Central Florida, 2006. http://digital.library.ucf.edu/cdm/ref/collection/ETD/id/3564.
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All-optical synchronization and its application in advanced optical communications have been investigated in this dissertation. Dynamics of all-optical timing synchronization (clock recovery) using multi-section gain-coupled distributed-feedback (MS-GC DFB) lasers are discussed. A record speed of 180-GHz timing synchronization has been demonstrated using this device. An all-optical carrier synchronization (phase and polarization recovery) scheme from PSK (phase shift keying) data is proposed and demonstrated for the first time. As an application of all-optical synchronization, the characterization of advanced modulation formats using a linear optical sampling technique was studied. The full characterization of 10-Gb/s RZ-BPSK (return-to-zero binary PSK) data has been demonstrated. Fast lockup and walk-off of the all-optical timing synchronization process on the order of nanoseconds were measured in both simulation and experiment. Phase stability of the recovered clock from a pseudo-random bit sequence signal can be achieved by limiting the detuning between the frequency of free-running self-pulsation and the input bit rate. The simulation results show that all-optical clock recovery using TS-DFB lasers can maintain a better than 5 % clock phase stability for large variations in power, bit rate and optical carrier frequency of the input data and therefore is suitable for applications in ultrafast optical packet switching. All-optical timing synchronization of 180-Gb/s data streams has been demonstrated using a MS-GC DFB laser. The recovered clock has a jitter of less than 410 fs over a dynamic range of 7 dB. All-optical carrier synchronization from phase modulated data utilizes a phase sensitive oscillator (PSO), which used a phase sensitive amplifier (PSA) as a gain block. Furthermore, all-optical carrier synchronization from 10-Gb/s BPSK data was demonstrated in experiment. The PSA is configured as a nonlinear optical loop mirror (NOLM). A discrete linear system analysis was carried out to understand the stability of the PSO. Complex envelope measurement using coherent linear optical sampling with mode-locked sources is investigated. It is shown that reliable measurement of the phase requires that one of the optical modes of the sampling pulses be locked to the optical carrier of the data signal to be measured. Carrier-envelope offset (CEO) is found to have a negligible effect on the measurement. Measurement errors of the intensity profile and phase depend on the pulsewidth and chirp of the sampling pulses as well as the detuning between the carrier frequencies of the data signal and the center frequency of the sampling source. Characterization of the 10-Gb/s RZ-BPSK signal was demonstrated using the coherent detection technique. Measurements of the optical intensity profile, chirp and constellation diagram were demonstrated. A CW local oscillator was used and electrical sampling was performed using a sampling scope. A novel feedback scheme was used to stabilize homodyne detection.Ph.D.
Other
Optics and Photonics
Optics
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Morey, Christopher. "Optimization models for synchronization planning". Thesis, Monterey, California. Naval Postgraduate School, 1991. http://hdl.handle.net/10945/26674.
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Lam, Chi Wa. "Synchronization in OFDM communication systems". Thesis, University of Surrey, 2003. http://epubs.surrey.ac.uk/928/.
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Chang, Hong-Shiu. "Dynamic synchronization of sympathetic oscillators". Thesis, University College London (University of London), 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.312647.
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Olsson, Carl. "Att arbeta med ”Synchronization management”". Thesis, Mittuniversitetet, Institutionen för elektronikkonstruktion, 2018. http://urn.kb.se/resolve?urn=urn:nbn:se:miun:diva-35713.
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This essay revolves around Synchronization management & Synchronization licensing, or in short sync. The development of sync as a career choice and profession has been fast and is still ongoing. It is not until later years that sync has become a proper profession, whereas before it was just part of a publisher or sales person’s regular work. In short, sync deals with the commercial use of copyright protected music. A synchronization manager negotiates fees and licensing agreements while handling the dialogue between commercial businesses, publishers and in some cases song writers. Once a deal has been made a Synchronization license is granted by the owner of the copyrighted music, allowing the licensee (the person wanting to use the material) to use the music according to the agreement. A Synchronization license is most commonly used when a company wants to use music in either commercial, television or any kind of visual media. To get a better understand of Synchronization management a series of interviews were conducted to get three different perspectives. The first interview helped establish what a synchronization manager actually does, and was held with a person who works with the profession in question. To better grasp the song writing point of view when it comes to sync an interview with a person who was writing for sync briefs was conducted. Lastly, a publisher was interviewed to help understand synchronization licensing from a publishing point of view. The result generated by the interviews in combination with already written articles about Synchronization management helped get a better understanding of the profession and how different individuals are using it in their daily life in music. The main question of this essay was to establish if sync is a reliable source of income for “up-and-coming” song writers and music producers.
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Patt, Boaz. "A theory of clock synchronization". Thesis, Massachusetts Institute of Technology, 1994. http://hdl.handle.net/1721.1/36954.
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Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 1995.Includes bibliographical references (p. 143-146) and index.
by Boaz Patt.
Ph.D.
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Gelashvili, Rati. "On the complexity of synchronization". Thesis, Massachusetts Institute of Technology, 2017. http://hdl.handle.net/1721.1/111856.
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Thesis: Ph. D., Massachusetts Institute of Technology, Department of Electrical Engineering and Computer Science, 2017.This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.
Cataloged from student-submitted PDF version of thesis.
Includes bibliographical references (pages 183-197).
The field of distributed algorithms revolves around efficiently solving synchronization tasks, such as leader election and consensus. We make contributions towards a better understanding of the complexity of central tasks in standard distributed models. In the population protocols model, we demonstrate how to solve majority and leader election efficiently, in time 0(log² n), using 0(log n) states per node, for n nodes. Central to our algorithms is a new leaderless phase clock technique. We also prove tight lower bounds on the state complexity of solving these tasks. In shared memory, we prove that any nondeterministic solo terminating consensus algorithm for anonymous processes has to use [omega](n) read-write registers. Then, we show how to solve n-process wait-free consensus by combining synchronization instructions that would be considered "weak" according to Herlihy's consensus hierarchy. This collapses the hierarchy when instructions can be applied to the same memory location, as is the case in all existing multicore processors. We suggest an alternative hierarchy and provide a practical universal construction using only "weak" instructions, that performs as well as the Compare-and-Swap-based solution. Space complexity of solving k-set agreement is a problem that highlights important gaps in our understanding and state-of-the-art methods. No general lower bound better than 2 is known. We introduce a new technique based on an indirect black-box application of Sperner's Lemma through an algorithmic reduction to the impossibility of wait-free k-set agreement. We design a simulation such that for any protocol either the simulating processes solve wait-free k-set agreement (impossible), or they simulate an execution of that uses many registers. Finally, time complexity of leader election is a long-standing open problem. We give an algorithm with 0(log* k) time complexity in asynchronous message-passing system, for k participants.
by Rati Gelashvili.
Ph. D.
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Lim, Beng-Hong. "Reactive synchronization algorithms for multiprocessors". Thesis, Massachusetts Institute of Technology, 1995. http://hdl.handle.net/1721.1/36018.
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Shaw, Christopher. "Synchronization for Burst-Mode APSK". International Foundation for Telemetering, 2009. http://hdl.handle.net/10150/606120.
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ITC/USA 2009 Conference Proceedings / The Forty-Fifth Annual International Telemetering Conference and Technical Exhibition / October 26-29, 2009 / Riviera Hotel & Convention Center, Las Vegas, NevadaWe derive bounds on the performance of data-aided joint estimators for timing offset, carrier phase offset, and carrier frequency offset for use in an APSK packet-based communication link. It is shown that the Cramér-Rao Bound (CRB) is a function of the training sequence, the signal-to-noise ratio (SNR), and the pulse shape. We also compute APSK training sequences of different lengths that minimize the CRB for each of the parameters.
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Frisk, Martin. "Synchronization in chaotic dynamical systems". Thesis, Uppsala universitet, Tillämpad matematik och statistik, 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-287624.
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Thom, Gary A. "COMPLEX FORMAT SYNCHRONIZATION AND DECOMMUTATION". International Foundation for Telemetering, 1991. http://hdl.handle.net/10150/612901.
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International Telemetering Conference Proceedings / November 04-07, 1991 / Riviera Hotel and Convention Center, Las Vegas, NevadaToday's advanced commutation systems and on-board computers present a difficult challenge to many existing ground station systems. This paper describes various complex telemetry formats generated by these airborne systems and further describes methods for synchronizing and decommutating these formats.
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Herrgård, Max. "Synchronization in the Lorenz system". Thesis, Uppsala universitet, Tillämpad matematik och statistik, 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-312814.
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Werner, Christopher, Hendrik Schön, Thomas Kühn, Sebastian Götz e Uwe Aßmann. "Role-based Runtime Model Synchronization". IEEE, 2018. https://tud.qucosa.de/id/qucosa%3A75310.
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Model-driven Software Development (MDSD) promotes the use of multiple related models to realize a software system systematically. These models usually contain redundant information but are independently edited. This easily leads to inconsistencies among them. To ensure consistency among multiple models, model synchronizations have to be employed, e.g., by means of model transformations, trace links, or triple graph grammars. Model synchronization poses three main problems for MDSD. First, classical model synchronization approaches have to be manually triggered to perform the synchronization. However, to support the consistent evolution of multiple models, it is necessary to immediately and continuously update all of them. Second, synchronization rules are specified at design time and, in classic approaches, cannot be extended at runtime, which is necessary if metamodels evolve at runtime. Finally, most classical synchronization approaches focus on bilateral model synchronization, i.e., the synchronization between two models. Consequently, for more than two models, they require the definition of pairwise model synchronizations leading to a combinatorial explosion of synchronization rules. To remedy these issues, we propose a role-based approach for runtime model synchronization. In particular, we propose role-based synchronization rules that enable the immediate and continuous propagation of changes to multiple interrelated models (and back again). Additionally, our approach permits adding new and customized synchronization rules at runtime. We illustrate the benefits of role-based runtime model synchronization using the Families to Persons case study from the Transformation Tool Contest 2017.
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Su, Ye. "Synchronization in message passing systems /". Search for this dissertation online, 2004. http://wwwlib.umi.com/cr/ksu/main.
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