Different Types Of Oscillations Research Articles

Design of Low Power and Low Phase Noise Current Starved Ring Oscillator for RFID Tag EEPROM

Power dissipation of CMOS IC is a key factor in low power applications especially in RFID tag memories. Generally, tag memories like electrically erasable programmable read-only memory (EEPROM) require an internal clock generator to regulate the internal voltage level properly. In EEPROM, oscillator circuit can generate any periodic clock signal for frequency translation. Among different types of oscillators, a current starved ring oscillator (CSRO) is described in this research due to its very low current biasing source, which in turn restrict the current flows to reduce the overall power dissipation. The designed CSRO is limited to three stages to reduce the power dissipation to meet the specs. The simulated output shows that, the improved CSRO dissipates only 4.9 mW under the power supply voltage (VDD) 1.2 V in Silterra 130 nm CMOS process. Moreover, this designed oscillator has the lowest phase noise -119.38 dBc/Hz compared to other research works. In addition, the designed CSRO is able to reduce the overall chip area, which is only 0.00114 mm2. Therefore, this proposed low power and low phase noise CSRO will be able to regulate the voltage level successfully for low power RFID tag EEPROM.

Periodic Model Containing Coupled Subsystems with Different Types of Oscillations

We consider a periodic model containing coupled subsystems (MCCS), which, when the coupling between subsystems vanishes, decomposes into systems of autonomous ordinary differential equations. We assume that the subsystems admit different types of non-degenerate single-frequency oscillations. We solve the problems of the existence of oscillations in the MCCS, their stability, natural stabilization of MCCS oscillations by smooth time-periodic coupling controls. We also provide an example.

ВИЗНАЧЕННЯ ПАРАМЕТРІВ МЕТАЛЕВОГО РЕЗОНАТОРА ВІБРАЦІЙНОГО ГІРОСКОПА АКУСТИЧНИМ МЕТОДОМ

The results of the development and determination of parameters of hightech, cheap coriolis vibratory gyroscope, which provides high accuracy of measurements and is not inferior to the characteristics of its main competitors: fiber-optic and laser gyroscopes, are presented in the work. It is shown that in order to increase the productivity and to reduce the cost of resonator manufacturing, it should be made of metal. The acoustic method is proposed, which allows to determine the Q-factor of different types of oscillations for an arbitrary number of heterogeneities, depending on their location in the resonator, as well as the parameters of the Q-factor of the resonator itself. The correctness of the heat treatment operations and the heterogeneity of mass distribution along cohesive coordinates of the resonator, as well as the possibility of using resonators at subsequent stages of assembling are evaluated.

Nonlinear dynamics of a non-autonomous network with coupled discrete–continuum oscillators

A network model of a multi-modular floating platform incorporated with a runway structure, viewed as a non-autonomous network with discrete–continuum oscillators, is developed for a general purpose of dynamic analysis. Numerical analysis shows the coupling effect between the two different types of oscillators on various complex dynamics, including sudden leaps, torus motions, beating vibrations, the synergetic effect of phase lock and anti-phase synchronizations. The amplitude death phenomenon, a suppressed weak oscillation state, is studied by using the fundamental solution derived by the averaging method. The parametric domain of the onset of amplitude death is illustrated to show the great significance to the stability design of the floating platform. The effect of the flexural rigidity of the runway on the distribution of amplitude death state is also discussed.

Water temperature fluctuation patterns in surface waters of the Tatra Mts., Poland

In this study, we aim to characterise natural variability of water temperature in surface waters of the Tatra Mts. and determine the dominant factors controlling its spatial diversity and seasonal patterns. For this purpose, a total of 33 time series of water temperature representing lakes, vaucluse springs and streams were analysed using the continuous wavelet transform (CWT). The periodicity analysis were conducted with the Morlet wavelet on hourly sampled data covering aperiod of 5 years. The principal components analysis (PCA) has been applied to describe the relationships among variables and extract potential sources of water temperature variability. The results showed an extremely high heterogeneity in temporal patterns of water temperature fluctuations among streams when compared to lakes and vaucluse springs. Wavelet analysis of water temperature time series revealed the presence of seven different configurations of periodical patterns. The lowest variability was observed among vaucluse springs that are supplied by groundwaters. Temporal fluctuations of water temperature in lakes contained four different types of oscillations. Streams were among the most diversified in terms of water temperature patterns exhibiting low, medium and high frequency behaviour. The PCA analysis confirmed the dependence of water temperature on weather conditions, catchment characteristics and flow rate explaining 88.97% of the total variability in the data. The results obtained from this study emphasize the importance of continuous data collection for capturing the long-term dynamics and consistent temporal patterns in time series. The study also demonstrates that wavelet analysis is helpful to identify cyclical patterns in time series of water temperature, and therefore may be useful in the classification of thermal regimes in surface waters.

Oscillatory Activity and Cross-Frequency Interactions in the Hippocampus and Connected Brain Structures during Sensory Information Processing

It has been suggested that oscillations, or rhythms, are required for the execution of many cognitive functions, as they support rapid and flexible interactions between neurons in different brain structures [Livanov, 1977; Fries, 2005; Womelsdorf et al., 2007]. Until recently, little attention was focused on the question of how different types of oscillations are synchronized during the processing of information arriving in the brain. We report here an analysis of the extent and correlations of rhythmic activity in the θ, α, and γ ranges in animals in two behavioral states: during calm consciousness and during the perception of sensory signals. Local field potentials (LFP) were recorded in eight brain structures (cortical and subcortical). Many areas showed increases in oscillatory activity in different frequency bands on delivery of sensory stimuli. The main result of this study was a sharp increase in the cross-frequency interactions of all rhythms in both cortical and subcortical structures during sensory information processing. We suggest that the increase in interfrequency interactions between different rhythms in different parts of the brain is required for detailed assessment of environmental signals and their registration in the memory system.

Oscillatory Control of Notch Signaling in Development.

The Notch effectors Hes1 and Hes7 and the Notch ligand Delta-like1 (Dll1) are expressed in an oscillatory manner during neurogenesis and somitogenesis. These two biological events exhibit different types of oscillations: anti-/out-of-phase oscillation in neural stem cells during neurogenesis and in-phase oscillation in presomitic mesoderm (PSM) cells during somitogenesis. Accelerated or delayed Dll1 expression by shortening or elongating the size of the Dll1 gene, respectively, dampens or quenches Dll1 oscillation at intermediate levels, a phenomenon known as "amplitude/oscillation death" of coupled oscillators. Under this condition, both Hes1 oscillation in neural stem cells and Hes7 oscillation in PSM cells are also dampened. As a result, maintenance of neural stem cells is impaired, leading to microcephaly, while somite segmentation is impaired, leading to severe fusion of somites and their derivatives, such as vertebrae and ribs. Thus, the appropriate timing of Dll1 expression is critical for the oscillatory expression in Notch signaling and normal processes of neurogenesis and somitogenesis. Optogenetic analysis indicated that Dll1 oscillations transfer the oscillatory information between neighboring cells, which may induce anti-/out-of-phase and in-phase oscillations depending on the delay in signaling transmission. These oscillatory dynamics can be described in a unified manner by mathematical modeling.

IDDES Evaluation of Oscillating Hydraulic Jumps

This paper presents the results of three-dimensional, unsteady, Improved Delayed Detached Eddy Simulations of an oscillating and a stable hydraulic jump at Froude numbers of 3.8 and 8.5, respectively. The different types of oscillations characterised in a hydraulic jump are analysed by evaluating the instantaneous flow field. The instability caused by the flapping wall-jet type flow in an oscillating jump is distinct compared to the jump-toe fluctuations caused by the spanwise vortices in the shear layer of a stable jump. These flow features are accurately captured by the simulations and are presented with pertinent discussions. The near-bed vortical structures in an oscillating jump is extracted and analysed using the λ2 criterion.

Analysis of types of oscillations of a double-frequency pendulum as oscillation model of water molecules

An analysis of the rotational oscillations of the protons of water molecules using a two-frequency pendulum model is made. The parameters showing the change in the type of pendulum oscillations are determined and the diagrams of the regions for different types of oscillations are constructed. The possibility of analyzing the type of vibrations of molecules in water, the boundary of the transition from independent two-frequency oscillations to ellipse-like rotations of protons of molecules near their bond axes in field of intermolecular interaction forces inhomogeneous in angle are shown

Complex Dynamics of Delay-Coupled Neural Networks

This paper reveals the complicated dynamics of a delay-coupled system that consists of a pair of sub-networks and multiple bidirectional couplings. Time delays are introduced into the internal connections and network-couplings, respectively. The stability and instability of the coupled network are discussed. The sufficient conditions for the existence of oscillations are given. Case studies of numerical simulations are given to validate the analytical results. Interesting and complicated neuronal activities are observed numerically, such as rest states, periodic oscillations, multiple switches of rest states and oscillations, and the coexistence of different types of oscillations.

Binary star detectability inKeplerdata from phase modulation of different types of oscillations

Detecting binary stars in photometric time series is traditionally done by measuring eclipses. This requires the orbital plane to be aligned with the observer. A new method without that requirement uses stellar oscillations to measure delays in the light arrival time and has been successfully applied to $\delta$ Scuti stars. However, application to other types of stars has not been explored. To investigate this we simulated light curves with a range of input parameters. We find a correlation between the signal-to-noise of the pulsation modes and the time delay required to detect binary motion. The detectability of the binarity in the simulations and in real $Kepler$ data shows strong agreement, hence, we describe the factors that have prevented this method from discovering binary companions to stars belonging to various classes of pulsating stars.

Guiding of atoms in helical optical potential structures

The classical dynamics of a cold atom trapped inside a static helical optical potential is investigated based on the Lagrangian formalism, which takes into account both the optical light field and the gravitational field. The resulting equations of motion are solved numerically and analytically. The topology of the helical optical potential, which drives the trapped cold atom, is responsible for two different types of oscillations, namely: the local oscillations, whereby the atomic motion is confined in a region smaller than the light field wavelength and the global oscillations, when the atomic motion is extended to larger regions comparable to the beam Rayleigh range Local oscillations guide the atom along the helical structure of the optical potential. The global oscillations, which constitute the main topic of our paper, define the atomic motion along the z-axis as an oscillation between two turning points. For typical values of the beam waist the turning points are symmetrical around the origin. For large values of the beam waist the global oscillations become asymmetric because the optical dipole potential weakens and the gravitational potential contributes to the determination of the turning points. For sufficiently large values of the beam waist there are no global oscillations and only one upper turning point defines the atom’s global motion.

The Motion Equation of a Spring-Magnet-Mass System Placed in Nonlinear Magnetic Field. An Analytical Solution of Elliptic Sine form Functions

In this work, w e are studying about a special oscillator system, which consists of one spring and a magnet-mass. The system is placed in nonlinear magnetic field, produced by two other permanent magnets, which are oriented for attraction, where can appear different types of oscillations. The magnetbody is simultaneously the subject of the linear field of spring and also of the nonlinear magnetic field of permanent magnets which has inverse quadratic dependence on distance. We are studying the ideal case, without friction, where the oscillations are produced wi th energy conservation, the oscillator system is started by applying the initial impulse and we consider the hypothesis that magnetic field produced by the permanent magnets is conservative and there is no loss of en ergy in the magnetic interactions. We are going to find the law of motion for the general case of study and a typically numerical application will be done.

Optimal Impedance Load of a Bistable Energy Harvester

AbstractIn this contribution we investigate a bistable energy harvester with regard to its optimal impedance load. A bistable energy harvester exhibits three different types of oscillation: Single‐well (about a stable equilibrium), cross‐well (between the wells) and inter‐well (about the unstable equilibrium). The occurring oscillation type depends, for instance, on the excitation parameters and the initial conditions. It has already been observed ( [1]) that the optimal impedance, which allows to maximize the power output, varies for each oscillation type. In our investigations we complement these findings with analytical and numerical calculations. For our analysis we examine the non‐dimensionalized coupled equations of a bistable energy harvester. (© 2015 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)

Stability, bifurcations and synchronization in a delayed neural network model of [formula omitted]-identical neurons

This paper deals with dynamic behaviors of Hopfield type neural network model of n(≥3) identical neurons with two time-delayed connections coupled in a star configuration. Delay dependent as well as independent local stability conditions about trivial equilibrium is found. Considering synaptic weight and time delay as parameters Hopf-bifurcation, steady-state bifurcation and equivariant steady state bifurcation criteria are given. The criterion for the global stability of the system is presented by constructing a suitable Lyapunov functional. Also conditions for absolute synchronization about the trivial equilibrium are also shown. Using normal form method and the center manifold theory the direction of the Hopf-bifurcation, stability and the properties of Hopf-bifurcating periodic solutions are determined. Numerical simulations are presented to verify the analytical results. The effect of synaptic weight and delay on different types of oscillations, e.g. in-phase, phase-locking, standing wave and oscillation death, has been shown numerically.

Feature of acoustic sound signals involved in vapor bubble condensation and its application in identification of condensation regimes

Experiments were carried out on the sound pressure oscillations condensation regime map, and bubble collapse frequency during the direct contact condensation of vapor with the aid of an acoustic hydrophone and a high-speed video camera. The injection rate of vapor and liquid subcooling in the experiments were 0.19–3.73m3/h and of 10–70K, respectively. Four different condensation regimes were identified according to features presented on the bubble surface and whether and when the bubble collapse occurred. The state-of-the-art signal processing methods (statistical, spectral, fractal and discrete wavelet transform analyses) were applied to processing the detected acoustic signals. The results showed that only the kurtosis and DWT in the four methods could distinguish the different regimes well. Furthermore, the spectral and fractal analyses showed that strongly persistent behavior in the signals corresponded to the dominant frequency in the range of 120–400Hz might be arisen from the periodic variation in the vapor bubble volume. While that corresponded to peaks with frequency higher than 7000Hz in transition and capillary wave regimes were probably the high-frequency oscillation in pressure induced by sudden bubble collapse. Contrarily, the first peak in 0–200Hz caused by the periodic bubble break-up or split-up was high anti-persistent. DWT analysis showed that the sound pressure oscillation introduced by bubble collapse was similar to that by bubble split-up for all condensation regimes, whereas at very high frequency two different types of oscillations arose. Furthermore, the bubble collapse frequency increased with increase in liquid subcooling and vapor injection rate, and could be obtained from the spectral and Hurst analyses of the signals indirectly.

Changes in the behavior and oscillatory activity in cortical and subcortical brain structures induced by repeated l-glutamate injections to the medial septal area in guinea pigs

Although the presence and importance of oscillations in cortical structures is well-documented, little is known about this rhythmic activity in subcortical areas. In waking guinea pigs, during their inattentive rest, local field potentials (LFPs) were recorded simultaneously in eight brain structures. In the cortical areas (prefrontal and entorhinal fields, hippocampus, dentate gyrus) and subcortical ones (medial and lateral septal nuclei, central nucleus of amygdala, and supramammillary nucleus), different types of oscillations were observed: delta (0.5–4Hz), theta (4–8), alpha (10–12), gamma (40–80), and high-frequency, presumable ripples (100–200Hz). In all structures, low-frequency oscillations (delta and theta) were more powerful than high-frequency ones. Structural communications in different bands of rhythmic activity were expressed differently. On the whole they were the more intensive, the stronger were the oscillations, however, this was not the absolute rule. A long-term (about a month) daily injection of l-glutamate into the medial septal region induced significant changes in theta, gamma, and high-frequency oscillations in most regions examined. The correlations of some structures also changed; they significantly decreased between the entorhinal cortex and hippocampus in the theta band and between the medial septum and central amygdala in the gamma band. During permanent septal glutamate infusion, distinct signs of epileptogenesis were revealed (epileptiform activity, seizure behavior of animals, and formation of aberrant fibers in the hippocampus). Thus, we believe that the glutamatergic system of medial septum can participate in the development of epilepsy. The earliest sign of pathology in electrical activity was alterations in high-frequency oscillations in the dentate gyrus and medial septum, but the strongest changes were in theta and especially gamma rhythms in many structures. The data obtained help to advance our understanding of the basic mechanisms of brain functioning and its disturbances in seizure pathology.

Variational formulation of oscillating fluid clusters and oscillator-like classification. I. Theory

The present work develops the theoretical framework to describe oscillations of fluid clusters. The basic physical phenomena are presented and justified assumptions lead to the final set of equations for different types of oscillations (pinned/sliding). The special combination of a liquid cluster surrounded by a rigid solid matrix and a gas is investigated in more detail. Furthermore, a classification of oscillating fluid clusters is presented using a one-dimensional oscillator model. This classification includes three dynamic properties: mass, eigenfrequency, and damping whereas conceptual implementation and limitations for use in multiphase theories are clearly indicated. The frequency dependent flow profile leads to frequency dependence of the dynamic parameters. This is discussed and represented by dimensionless numbers.

Developmental Reduction of Asynchronous GABA Release from Neocortical Fast-Spiking Neurons

Delayed asynchronous release (AR) evoked by bursts of presynaptic action potentials (APs) occurs in certain types of hippocampal and neocortical inhibitory interneurons. Previous studies showed that AR provides long-lasting inhibition and desynchronizes the activity in postsynaptic cells. However, whether AR undergoes developmental change remains unknown. In this study, we performed whole-cell recording from fast-spiking (FS) interneurons and pyramidal cells (PCs) in prefrontal cortical slices obtained from juvenile and adult rats. In response to AP trains in FS neurons, AR occurred at their output synapses during both age periods, including FS autapses and FS-PC synapses; however, the AR strength was significantly weaker in adults than that in juveniles. Further experiments suggested that the reduction of AR in adult animals could be attributable to the rapid clearance of residual Ca(2+) from presynaptic terminals. Together, our results revealed that the AR strength was stronger at juvenile but weaker in adult, possibly resulting from changes in presynaptic Ca(2+) dynamics. AR changes may meet the needs of the neural network to generate different types of oscillations for cortical processing at distinct behavioral states.

Group synchronization in complex dynamical networks with different types of oscillators and adaptive coupling schemes

This paper focus on schemes and corresponding criteria for group synchronization in complex dynamical networks consisted of different group of chaotic oscillators. The global asymptotically stable criteria for a linearly or adaptively coupled network are derived to ensure each group of oscillators synchronize to the same behavior. Theoretical analysis and numerical simulation results show that the group synchronization can be guaranteed by enhancing the external coupling strength whenever there are connections or not within the groups under the “same input” condition. All of the results are proved rigorously. Finally, a network with three groups, a scale-free sub-network, a small-world sub-network and a ring sub-network, is illustrated, and the corresponding numerical simulations verify the theoretical analysis.