Blinking System Research Articles

Efficient characterization of blinking quantum emitters from scarce data sets via machine learning

Single photon emitters are core building blocks of quantum technologies, with established and emerging applications ranging from quantum computing and communication to metrology and sensing. Regardless of their nature, quantum emitters universally display fluorescence intermittency or photoblinking: interaction with the environment can cause the emitters to undergo quantum jumps between on and off states that correlate with higher and lower photoemission events, respectively. Understanding and quantifying the mechanism and dynamics of photoblinking is important for both fundamental and practical reasons. However, the analysis of blinking time traces is often afflicted by data scarcity. Blinking emitters can photo-bleach and cease to fluoresce over time scales that are too short for their photodynamics to be captured by traditional statistical methods. Here, we demonstrate two approaches based on machine learning that directly address this problem. We present a multi-feature regression algorithm and a genetic algorithm that allow for the extraction of blinking on/off switching rates with ⩾85% accuracy, and with ⩾10× less data and ⩾20× higher precision than traditional methods based on statistical inference. Our algorithms effectively extend the range of surveyable blinking systems and trapping dynamics to those that would otherwise be considered too short-lived to be investigated. They are therefore a powerful tool to help gain a better understanding of the physical mechanism of photoblinking, with practical benefits for applications based on quantum emitters that rely on either mitigating or harnessing the phenomenon.

Multistable ghost attractors in a switching laser system.

This paper studies the effects of a switching parameter on the dynamics of a multistable laser model. The laser model represents multistability in distinct ranges of parameters. We assume that the system's parameter switches periodically between different values. Since the system is multistable, the presence of a ghost attractor is also dependent on the initial condition. It is shown that when the composing subsystems are chaotic, a periodic ghost attractor can emerge and vice versa, depending on the initial conditions. In contrast to the previous studies in which the attractor of the fast blinking systems approximates the average attractor, here, the blinking attractor differs from the average in some cases. It is shown that when the switching parameter values are distant from their average, the blinking and the average attractors are different, and as they approach, the blinking attractor approaches the average attractor too.

Real time eye based Password Authentication by Eye Blinking System

Real time eye based Password Authentication by Eye Blinking System

On dynamics of 4-D blinking chaotic system and voice encryption application

A new four-dimensional chaotic system with four cross-terms is investigated in this study. The dynamical behaviors of the system and codimension-one bifurcations are analyzed both theoretically and numerically. The influences of the system’s parameters on its nonlinear dynamics are explored. Then, a proposed four-dimensional blinking system is introduced based on the new chaotic system. More interestingly, the possible occurrence of ghost attractors in the phase space of the blinking system is verified and has been illustrated through several examples. The encryption keystream was generated dynamically using pre-treated chaotic mixed sequences and was used to mask the voice bitstream to protect voice data integrity. Finally, a voice encryption example employing the 4-D blinking chaotic system of the proposed system is presented.

Ghost attractor in fractional order blinking system and its application

In this paper, the occurrence of ghost attractor is verified in three cases of a proposed fractional order Rössler blinking system. Firstly, the dynamical behaviors of the short memory fractional order prototype-4 Rössler system with Chua’s diode are explored via bifurcation diagrams and Lyapunov exponents. It is depicted that this system exhibits a variety of dynamics including limit cycles, period doubling and chaos. Then, a proposed non-autonomous fractional order Rössler blinking system is introduced. Numerical simulations are employed to confirm the existence of ghost attractors at specific cases which involve very fast switching time between two composing autonomous fractional subsystems. It is found that the presented fractional order blinking system is very sensitive to system parameters, initial conditions, and stochastic process parameters. Thus, the induced chaotic ghost attractor is utilized in a suggested ghost attractor-based chaotic image encryption scheme for first time. Finally, a detailed security analysis is carried out and reveals that the proposed image cryptosystem is immune against different types of attacks such as differential attacks, brute force attacks, cropping and statistical attacks.

Ghost attractors in blinking Lorenz and Hindmarsh-Rose systems.

In this paper, we consider blinking systems, i.e., non-autonomous systems generated by randomly switching between several autonomous continuous time subsystems in each sequential fixed period of time. We study cases where a non-stationary attractor of a blinking system with fast switching unexpectedly differs from the attractors of composing subsystems. Such a non-stationary attractor is associated with an attractor of the averaged system being a ghost attractor of the blinking system [Belykh et al., Phys. D: Nonlinear Phenom. 195, 188 (2004); Hasler et al., SIAM J. Appl. Dyn. Syst. 12, 1031 (2013); Belykh et al., Eur. Phys. J. Spec. Top. 222, 2497 (2013)]. Validating the theory of stochastically blinking systems [Hasler et al., SIAM J. Appl. Dyn. Syst. 12, 1031 (2013); Hasler et al., SIAM J. Appl. Dyn. Syst. 12, 1007 (2013)], we demonstrate that fast switching between two Lorenz systems yields a ghost chaotic attractor, even though the dynamics of both systems are trivial and defined by stable equilibria. We also study a blinking Hindmarsh-Rose system obtained from the original model of neuron activity by using randomly switching sequence as an external stimulus. Despite the fact that the values of the external stimulus are selected from a set corresponding to the tonic spiking mode, the blinking model exhibits bursting activity. For both systems, we analyze changes in the dynamical behavior as the period of stochastic switching increases. Using a numerical approximation of the invariant measures of the blinking and averaged systems, we give estimates of a non-stationary and ghost attractors' proximity.

Non-stationary attractors in the blinking systems: ghost attractor of Lorenz type

In this paper we consider blinking systems, i.e. the systems randomly changing its structure in each sequential fixed period of time. Our goal is to find ghost attractors which arise in a blinking system being unexpectively different with respect to the attractors of composing systems. We study two blinking systems. One of them is a nonlinear rotator with switching torque and another is a blinking piecewise-linear Lorenz-type system. We prove the existence of ghost attractors in both cases for certain parameter ranges.

The B-Link System: A British Best Practice Becomes a Nursing-Led Innovative Program in the United States

The B-Link System: A British Best Practice Becomes a Nursing-Led Innovative Program in the United States

Evaluation for Students’ Learning Manner Using Eye Blinking System in Metaverse

For a virtual problem-based learning (PBL) class in Metaverse, an eye blinking system for avatars was introduced. It correlated their eye blinking behavior with an emotional response to various problems that they were asked to discuss on behalf of their users. Three Japanese college students joined the project where they discussed a simple and difficult problem, respectively. Teachers proposed online (mathematical problems) for them. Each session was 10 minutes in length. During the classes, the number of eye blinks was recorded for each student by using special software. After completing the PBL classes, the students answered questionnaires. Then the results were analyzed. All of the results suggested that the difficult question would make students’ feelings unstable and increase the number of eye blinks. Using this system, teachers could analyze students’ responses well to achieve a better outcome of virtual PBL.

Dynamics of Stochastically Blinking Systems. Part I: Finite Time Properties

We consider dynamical systems whose parameters are switched within a discrete set of values at equal time intervals. Similar to the blinking of the eye, switching is fast and occurs stochastically and independently for different time intervals. There are two time scales present in such systems, namely the time scale of the dynamical system and the time scale of the stochastic process. If the stochastic process is much faster, we expect the blinking system to follow the averaged system where the dynamical law is given by the expectation of the stochastic variables. We prove that, with high probability, the trajectories of the two systems stick together for a certain period of time. We give explicit bounds that relate the probability, the switching frequency, the precision, and the length of the time interval to each other. We discover the apparent presence of a soft upper bound for the time interval, beyond which it is almost impossible to keep the two trajectories together. This comes as a surprise in view of the known perturbation analysis results. From a probability theory perspective, our results are obtained by directly deriving large deviation bounds. They are more conservative than those derived by using the action functional approach, but they are explicit in the parameters of the blinking system.

Dynamics of Stochastically Blinking Systems. Part II: Asymptotic Properties

We study stochastically blinking dynamical systems as in the companion paper (Part I). We analyze the asymptotic properties of the blinking system as time goes to infinity. The trajectories of the averaged and blinking system cannot stick together forever, but the trajectories of the blinking system may converge to an attractor of the averaged system. There are four distinct classes of blinking dynamical systems. Two properties differentiate them: single or multiple attractors of the averaged system and their invariance or noninvariance under the dynamics of the blinking system. In the case of invariance, we prove that the trajectories of the blinking system converge to the attractor(s) of the averaged system with high probability if switching is fast. In the noninvariant single attractor case, the trajectories reach a neighborhood of the attractor rapidly and remain close most of the time with high probability when switching is fast. In the noninvariant multiple attractor case, the trajectory may escape to another attractor with small probability. Using the Lyapunov function method, we derive explicit bounds for these probabilities. Each of the four cases is illustrated by a specific example of a blinking dynamical system. From a probability theory perspective, our results are obtained by directly deriving large deviation bounds. They are more conservative than those derived by using the action functional approach, but they are explicit in the parameters of the blinking system.

Aging of the trigeminal blink system.

This study characterizes trigeminal blinks in normal human subjects between 20 and 80 years of age, 60-year-old Parkinson's disease patients, and young and old guinea pigs. In normal humans over 60 years of age, lid-closing duration, and the excitability and latency of the trigeminal reflex blink increase significantly relative to younger subjects. Aged guinea pigs appear to display similar increases in reflex blink duration and latency. Reflex blink amplitude, however, does not change consistently with age. For subjects less than 70 years of age, a unilateral trigeminal stimulus evokes a 37% larger blink in the eyelid ipsilateral to the stimulus than in the contralateral eyelid, but 70-year-olds exhibit blinks of equal amplitude. In all cases, blink duration is identical for the two eyelids. If normal, age-related loss of dopamine neurons explains these trigeminal blink modifications, then Parkinson's disease should exaggerate age-related changes in these blink parameters. Preliminary data show that Parkinson's disease increases blink duration and excitability relative to age-matched control subjects. Thus, it seems likely that normal, age-related loss of dopamine neurons accounts for increases in trigeminal blink excitability and duration. A previously uncharacterized type of trigeminally evoked blink appears after age 40 in humans and in aged guinea pigs. In subjects less than 40 years old, a single trigeminal stimulus elicits a single reflex blink. In subjects over age 40, however, a single stimulus frequently evokes a reflex blink and additional blinks that occur at a fixed interval relative to the preceding blink. These "blink oscillations" may arise from oscillatory processes within trigeminal reflex blink circuits. The presence of exaggerated blink oscillations in subjects with dry eye and benign essential blepharospasm suggests that an alteration of blink oscillation mechanisms plays a critical role in these disorders.

Blink-perturbed saccades in monkey. I. Behavioral analysis.

Saccadic eye movements are thought to be influenced by blinking through premotor interactions, but it is still unclear how. The present paper describes the properties of blink-associated eye movements and quantifies the effect of reflex blinks on the latencies, metrics, and kinematics of saccades in the monkey. In particular, it is examined to what extent the saccadic system accounts for blink-related perturbations of the saccade trajectory. Trigeminal reflex blinks were elicited near the onset of visually evoked saccades by means of air puffs directed on the eye. Reflex blinks were also evoked during a straight-ahead fixation task. Eye and eyelid movements were measured with the magnetic-induction technique. The data show that saccade latencies were reduced substantially when reflex blinks were evoked prior to the impending visual saccades as if these saccades were triggered by the blink. The evoked blinks also caused profound spatial-temporal perturbations of the saccades. Deflections of the saccade trajectory, usually upward, extended up to approximately 15 degrees. Saccade peak velocities were reduced, and a two- to threefold increase in saccade duration was typically observed. In general, these perturbations were largely compensated in saccade mid-flight, despite the absence of visual feedback, yielding near-normal endpoint accuracies. Further analysis revealed that blink-perturbed saccades could not be described as a linear superposition of a pure blink-associated eye movement and an unperturbed saccade. When evoked during straight-ahead fixation, blinks were accompanied by initially upward and slightly abducting eye rotations of approximately 2-15 degrees. Back and forth wiggles of the eye were frequently seen; but in many cases the return movement was incomplete. Rather than drifting back to its starting position, the eye then maintained its eccentric orbital position until a downward corrective saccade toward the fixation spot followed. Blink-associated eye movements were quite rapid, albeit slower than saccades, and the velocity-amplitude-duration characteristics of the initial excursions as well as the return movements were approximately linear. These data strongly support the idea that blinks interfere with the saccade premotor circuit, presumably upstream from the neural eye-position integrator. They also indicated that a neural mechanism, rather than passive elastic restoring forces within the oculomotor plant, underlies the compensatory behavior. The tight latency coupling between saccades and blinks is consistent with an inhibition of omnipause neurons by the blink system, suggesting that the observed changes in saccade kinematics arise elsewhere in the saccadic premotor system.

The role of blink adaptation in the pathophysiology of benign essential blepharospasm.

To investigate eyelid movements in patients with benign essential blepharospasm (BEB), with an emphasis on the characterization of the kinematics of normal and spastic blinks, assessment of interocular differences, and further delineation of the role of adaptive blink mechanisms in eyelid movement disorders. The electromagnetic search coil technique was used to record the metrics of blinks bilaterally in 5 patients with untreated BEB. Eyelid kinematics and the main-sequence (peak velocity vs amplitude) relationships were analyzed. Patients with BEB exhibited a decrease in blink amplitude and peak velocity. Moreover, the main-sequence slope was decreased bilaterally. Spasms were bilateral and relatively conjugate. There was no change in the coordination of normal blinking across the 2 eyelids. These data demonstrate the operation of the adaptive regulation of blinking in an eyelid movement disorder. The findings suggest that the adaptive regulation of blink is a bilateral event. Blink-adaptive control systems can act on the blink reflex excitability and main-sequence relationships, changing these either together or independently. The hyperexcitable blink reflex of BEB is met by what is believed to be an adaptive decrease in the main-sequence slope that would decrease the strength of debilitating spasms. Collectively, these data extend the knowledge of the pathophysiology of BEB and, perhaps more important, establish the role of blink system plasticity in eyelid movement disorders.

Animal model explains the origins of the cranial dystonia benign essential blepharospasm.

The current study demonstrates that combining two mild alterations to the rat trigeminal reflex blink system reproduces the symptoms of benign essential blepharospasm, a cranial dystonia characterized by uncontrollable spasms of blinking. The first modification, a small striatal dopamine depletion, reduces the tonic inhibition of trigeminal reflex blink circuits. The second alteration, a slight weakening of the lid-closing orbicularis oculi muscle, begins an adaptive increase in the drive on trigeminal sensory-motor blink circuits that initiates blepharospasm. By themselves, neither of these modifications causes spasms of lid closure, but combined, they induce bilateral forceful blinking and spasms of lid closure. A two-factor model based on these rodent experiments may explain the development of benign essential blepharospasm in humans. The first factor, a subclinical loss of striatal dopamine, creates a permissive environment within the trigeminal blink circuits. The second factor, an external ophthalmic insult, precipitates benign essential blepharospasm. This two-factor model may also be applicable to the genesis of other cranial dystonias.

Blinking Detection Methods for Loran-C

To ensure integrity of the Loran-C radionavigation system during non-precision approaches, an automatic blinking system notifies the user when the system is not functioning within specifications. To be certain that timely detection of this blinking can be guaranteed, one of the requirements imposed on an airborne Loran-C receiver is that it should flag an alert when the signal to noise ratio drops below –6 . This paper addresses some blinking detection methods, that will ensure safe operation beyond this –6 dB limit. A preliminary version of this article was presented at the Wild Goose Conference in Birmingham, August 1992.

A Limit Theorem for the Solutions of Differential Equations with Random Right-Hand Sides

A Limit Theorem for the Solutions of Differential Equations with Random Right-Hand Sides