Reliability aspects in a dynamic time-to-failure degradation-based model

Although the ordinary time-to-failure degradation-based model has been extensively used in practice, it also has its limitations. In this paper, we consider a time-to-failure degradation-based model recently proposed by Albabtain et al., where a limiting conditional survival probability entertains further stochastic relationships between the failure time and the degree of degradation. In the particular case where the limited survival probability is available for the proportional failure rate model, the model is developed using two well-known degradation paths, namely the additive degradation path and the multiplicative degradation path, each of which has a component of random variation. Preservation of various stochastic orders and aging properties of the random variation component in the model in the described setting is developed. To illustrate the model in the modified design, some examples of interest in reliability are presented.

Ghostly pasts and postponed futures: The disorder of time during the corona pandemic

Since the first lockdown in March 2020, time seems to have slowed to a continuous present tense. The Greek language has three words to express different experiences of time: aion, chronos and kairos. If aion is the boundless and limbo-like time of eternity, chronos represents chronological, sequential, and linear time. Kairos, however, signifies the rupture of ordinary time with the opportune moment, epiphany and redemption, revolution, and most broadly, crisis and emergency. This paper argues that the pandemic is impacting how individuals perceive time in two ways: first, as a distortion of time in which individuals are caught between linear time ( chronos) and rupture ( kairos) invoking the state of emergency and second, as an extended present that blurs the passing of chronological time with its seeming eternity ( aion). As a result of the perceived suspension of ordinary time, temporal understandings of the future are postponed, while the past hovers like a ghost over the present.

TE-ESN: Time Encoding Echo State Network for Prediction Based on Irregularly Sampled Time Series Data

Prediction based on Irregularly Sampled Time Series (ISTS) is of wide concern in real-world applications. For more accurate prediction, methods had better grasp more data characteristics. Different from ordinary time series, ISTS is characterized by irregular time intervals of intra-series and different sampling rates of inter-series. However, existing methods have suboptimal predictions due to artificially introducing new dependencies in a time series and biasedly learning relations among time series when modeling these two characteristics. In this work, we propose a novel Time Encoding (TE) mechanism. TE can embed the time information as time vectors in the complex domain. It has the properties of absolute distance and relative distance under different sampling rates, which helps to represent two irregularities. Meanwhile, we create a new model named Time Encoding Echo State Network (TE-ESN). It is the first ESNs-based model that can process ISTS data. Besides, TE-ESN incorporates long short-term memories and series fusion to grasp horizontal and vertical relations. Experiments on one chaos system and three real-world datasets show that TE-ESN performs better than all baselines and has better reservoir property.

Patient Satisfaction with Private Recovery Services and Importance of Physician Behavior during COVID Time

Introduction: Patient satisfaction represents an essential indicator of the quality of care in the medical recuperation sector. This study aimed to identify the degree of satisfaction in patients who benefit from medical recuperation services in one private clinic from Romania and the factors that played a part in this respect. Method: An online questionnaire was completed by 105 patients of a private clinic in the period immediately following the opening of the clinic after the quarantine period due to COVID-19. The following concepts were measured: general satisfaction with clinical recuperation services (SG), physician’s behavior (PB), the impact of interventions on the state of health (IHI), modern equipment (ME), and the intention to return to the clinic (IRC). Based on a linear regression model, the impact of PB, IHI, ME, and IRC variables on general satisfaction (SG) was established. Results: The study results confirm the data from studies carried out in different sociocultural contexts in ordinary time, where physician behavior is the most crucial factor in patients’ satisfaction. Therefore, we can say that the physiotherapist’s behavior has an essential role in determining the patients’ satisfaction both in ordinary time and in COVID-19 time. The data in this study reflect the fact that satisfaction with the services offered by a medical recuperation clinic is a predictor for using the services in the future. Still, our study reflects a moderate relationship in intensity.

Translational symmetries of quadratic Lagrangians

In this paper, we show that a quadratic Lagrangian, with no constraints, containing ordinary time derivatives up to the order [Formula: see text] of [Formula: see text] dynamical variables, has [Formula: see text] symmetries consisting in the translation of the variables with solutions of the equations of motion. We construct explicitly the generators of these transformations and prove that they satisfy the Heisenberg algebra. We also analyze other specific cases which are not included in our previous statement: the Klein–Gordon Lagrangian, [Formula: see text] Fermi oscillators and the Dirac Lagrangian. In the first case, the system is described by an equation involving partial derivatives, the second case is described by Grassmann variables and the third shows both features. Furthermore, the Fermi oscillator and the Dirac field Lagrangians lead to second class constraints. We prove that also in these last two cases there are translational symmetries and we construct the algebra of the generators. For the Klein–Gordon case we find a continuum version of the Heisenberg algebra, whereas in the other cases, the Grassmann generators satisfy, after quantization, the algebra of the Fermi creation and annihilation operators.

Design of an optimal preview controller for linear discrete-time periodic systems

In this paper, the preview tracking control problem for linear discrete-time periodic systems is considered. First, to overcome the difficulty arising from periodicity of the system, the linear discrete-time periodic system is transformed into an ordinary time-invariant system by lifting method. Secondly, the difference between a system state and its steady-state value is used to derive an augmented system instead of the usual difference between system states. Then, the preview controller for the augmented system is proposed by the preview control theory, which solves the preview tracking control problem for the periodic systems. Moreover, an integrator is introduced to ensure that the output can track the reference signal without static error. Finally, the obtained results are illustrated by the simulation examples.

Caputo Fractional Derivative and Quantum-Like Coherence

We study two forms of anomalous diffusion, one equivalent to replacing the ordinary time derivative of the standard diffusion equation with the Caputo fractional derivative, and the other equivalent to replacing the time independent diffusion coefficient of the standard diffusion equation with a monotonic time dependence. We discuss the joint use of these prescriptions, with a phenomenological method and a theoretical projection method, leading to two apparently different diffusion equations. We prove that the two diffusion equations are equivalent and design a time series that corresponds to the anomalous diffusion equation proposed. We discuss these results in the framework of the growing interest in fractional derivatives and the emergence of cognition in nature. We conclude that the Caputo fractional derivative is a signature of the connection between cognition and self-organization, a form of cognition emergence different from the other source of anomalous diffusion, which is closely related to quantum coherence. We propose a criterion to detect the action of self-organization even in the presence of significant quantum coherence. We argue that statistical analysis of data using diffusion entropy should help the analysis of physiological processes hosting both forms of deviation from ordinary scaling.

Ghosting history/historicizing the ghost: Time passage in T. C. Haliburton’s The Old Judge

This article investigates the representation of time in T. C. Haliburton’s The Old Judge as shaped by the writer’s British North American context as well as his political background and agenda. It pays attention to the manner in which the text prepares the ground for native identity formation by providing a version of Nova Scotia’s recent history that is nonetheless presented as bygone and ancient. In The Old Judge, temporal distance of the past, apart from its richness — both confirmed by the presence of the properly historicized settler ghost — is the condition for cultural distinctiveness, maturity and heritage. Approaching The Old Judge from the perspective of Cynthia Sugars’ Canadian Gothic and Lorenzo Veracini’s settler colonialism, I argue that the text represents the past of the province as curiously extended in time in the Old World fashion, so that it may encompass the stages of cultural development required to gain the Empire’s recognition. Simultaneously, the text’s intricate play with heterochronies suggests that Haliburton’s Nova Scotia contains heterotopic spaces in Foucauldian terms, where the ordinary time passage is necessarily breached for the colony to attain proper legacy and distinct cultural status.

Forked Times: Documenting “Ordinary Time” in Everyday Life

“Ordinary” time is commonly defined as time that is neither holidays nor emergencies, which suggests that “ordinary time” events are routine rather than singular. An analysis of how people document events in “ordinary” time, however, shows that the stream of “ordinary” time has multiple forks; that ordinary does not necessarily mean predictable, and that both vacations and emergencies could, in certain circumstances, take on the character of routine rather than singular events. Le temps «ordinaire» est généralement défini comme un temps qui n'est ni des vacances ni des urgences, ce qui suggère que les événements «ordinaires» sont routiniers plutôt que singuliers. Une analyse de la manière dont les gens documentent les événements en temps «ordinaire» montre cependant que le flux du temps «ordinaire» a plusieurs fourchettes; cet ordinaire ne signifie pas nécessairement prévisible et que les vacances et les urgences pourraient, dans certaines circonstances, prendre le caractère d'événements routiniers plutôt que singuliers.