This article develops a novel design principle for the observer of timed discrete event systems behaving under specific time semantics. Observers devoted to discrete event systems usually ignore the ...timing aspects of underlying systems but this can have implications to many applications, in particular, for refinement of estimation and inference tasks. The techniques of this article use the time stamps of observations to refine the state estimation process for a class of labeled and timed automata where events occur based on constant time values. The resulting timed observer is beneficial for refining privacy and security issues. Current-state opacity is discussed as a promising application of the timed observer.
The Paleoproterozoic Era was a time of remarkable importance in the redox evolution of Earth's atmosphere and oceans. Here, we present a multi-proxy study of Mo, U and Fe isotopes together with Fe ...speciation of black shales and siltstones from the upper Zaonega Formation of the Onega Basin in Karelia. We attempt to better understand oceanic redox conditions during the 2.05Ga Shunga Event as the next step following the Great Oxidation Event (GOE) and the Lomagundi carbon isotope excursion Event.
A cautious examination of the Fe speciation data shows that the studied section was deposited under dominantly euxinic conditions (anoxic and sulfidic) and that the lower part of the section experienced metamorphism through which pyrite was altered to pyrrhotite. During this episode, the system was closed with respect to Fe but not sulfur. The Mo and U isotopic compositions (corrected for detrital input) were not affected by the metamorphism and loss of S and are fairly uniform throughout the entire section. The Fe isotope compositions are exceptionally heavy in the lower part of the section (up to δ56FeIRMM-14=0.83‰) and become lighter towards the upper intervals, which also show significant Mo and U enrichments. We suggest that this pattern reflects changes in the position of the deposition site relative to the redox structure of the water column. The upper part was deposited within a locally euxinic portion of the basin where H2S availability was highest, removal of Mo and U was more efficient and precipitated pyrite captured relatively non-fractionated dissolved Fe. In other words, quantitative uptake of Fe was favored. In contrast, the lower interval was deposited on the lower margin of a euxinic wedge where H2S availability was lower, and removal of Mo and U was less efficient. Pyrite precipitation in this part of the water column reflected a more fractionated dissolved Fe reservoir due to more protracted, non-quantitative Fe uptake because of less efficient pyrite formation under lower sulfide conditions and greater access to the large oceanic pool of Fe. The U isotopic signal was corrected for detrital contribution giving compositions similar to the riverine input and suggesting that co-precipitation into carbonates was the main process of U removal at this time.
We estimate the Mo isotope composition of the contemporaneous ocean to be δ98MoSW=0.85±0.21‰. This is the lowest value yet reported for the Proterozoic ocean, suggesting that the oceanic Mo cycle was dominated by euxinic and anoxic sinks with negligible Mo removal into oxic environments. Recent studies have proposed a sharp increase in ocean–atmosphere oxygen levels during the Lomagundi Event followed by a dramatic crash. Our results from black shales of the 2.05Ga Shunga Event are consistent with a post-Lomagundi decrease in biospheric oxygen levels.
•We studied Mo, U and Fe isotopes, and Fe speciation of the Shunga Event black shale.•We identified a metamorphic event of sulfur loss and pyrite alteration to pyrrhotite.•The post-depositional event did not affect the Mo, U and Fe isotope systems.•The chemostratigraphy suggests a pulse of oxidative weathering and/or redox changes.•Mo isotopes reflect an exceptionally anoxic ocean with widespread euxinia.
We offer a new account of event representation based on those aspects of object representation that encode an object's history, and which convey the distinct states that an object has experienced ...across time-minimally reflecting the before and after of whatever changes the object undergoes as an event unfolds. Our intention is to account for the content of event representations. For an event that can be described as "the chef chopped the onion," the event as a whole is defined by the changes in state and location, across time, of the onion, the chef, and any instruments that (might have) mediated the interaction between the chef and the onion. Thus, we maintain that events are encoded as "ensembles of intersecting object histories" in which one or more objects change state. Our approach requires not just the distinction between object types and object tokens, but also between tokens and token-states (e.g., between that specific onion and its different states before, during, and after the chopping). These distinctions require an account of how object tokens are represented within the context of episodic and semantic memory, and how distinct object states are bound into a single object identity. We shall argue that the theoretical pieces, and their neural instantiation, are in place to develop a unified account of event representation in which such representation is simply a consequence of the mechanism for generating object tokens, their histories, and the binding of one to the other.
The resilience of events has been primarily entangled to the recovery and coping capacity of the host destination. This approach considers events to be destination dependent, omitting sufficient ...consideration on an event's internal systemic dynamics that dictate its inherent self-organizing
and adapting capacity to externalities at operational level. This study adopts a systems thinking approach to explore the dynamic interface of interacting elements, attributes, and actors that dictate an event's identity, structure, and behavior, as grounding foundations of its operational
resilience independently to the hosting destination. Resilience thinking has been employed through the exploration of the seven principles of socioecological systems (SES) resilience. Building on the contextualization of academic events, the study applied a qualitative research design to explore
perceptions, attitudes, and experiences of primary academic event stakeholders (participants, attendees, keynotes, members of event academic committee, and members of event organization) during the period of COVID-19 pandemic. Research findings contribute to the conceptualization and operationalization
of operational academic and business event resilience, through the identification of enablers and inhibitors from the perspective of primary stakeholders. From a managerial perspective, research findings inform event contingencies and management during times of system disturbance with the
aim to ensure event viability and multistakeholder value satisfaction.
In task switching, an interaction between task and response is often observed, with response repetition (RR) benefits in task‐repeat trials and RR costs in task‐switch trials. The theoretical ...accounts of the RR effect remain controversial, and neuroscience evidence is scarce. The present study utilized the event‐related potentials (ERPs) method to explore the neural mechanism underlying the RR effect by adopting a cued task‐switching paradigm. The ERP results revealed the interaction between task and response in the P3b time window, with a response switch positivity under task‐repetition conditions and an RR positivity under task‐switching conditions. In addition, there were RR positivity in the N2 irrespective of task transition and in the late component (LC, 550–600 ms) that only under the task repetition condition. On the individual level, the RR benefit positively correlated with the RR positivity in the LC, while the RR costs negatively correlated with RR positivity in the N2/P3 component. These results suggest that both response reconfiguration and episodic‐retrieval make contributions to the RR effects, which were also discussed in terms of predictive model for a domain‐general inference and learning of perceptual categories.
Event stratigraphy is used to help characterise the Anthropocene as a chronostratigraphic concept, based on analogous deep-time events, for which we provide a novel categorization. Events in ...stratigraphy are distinct from extensive, time-transgressive ‘episodes’ – such as the global, highly diachronous record of anthropogenic change, termed here an Anthropogenic Modification Episode (AME). Nested within the AME are many geologically correlatable events, the most notable being those of the Great Acceleration Event Array (GAEA). This isochronous array of anthropogenic signals represents brief, unique events evident in geological deposits, e.g.: onset of the radionuclide ‘bomb-spike’; appearance of novel organic chemicals and fuel ash particles; marked changes in patterns of sedimentary deposition, heavy metal contents and carbon/nitrogen isotopic ratios; and ecosystem changes leaving a global fossil record; all around the mid-20th century. The GAEA reflects a fundamental transition of the Earth System to a new state in which many parameters now lie beyond the range of Holocene variability. Globally near-instantaneous events can provide robust primary guides for chronostratigraphic boundaries. Given the intensity, magnitude, planetary significance and global isochroneity of the GAEA, it provides a suitable level for recognition of the base of the Anthropocene as a series/epoch.
We construct asymptotically flat, spinning, regular on and outside an event horizon, scalarized black holes (SBHs) in extended scalar-tensor-Gauss-Bonnet models. They reduce to Kerr BHs when the ...scalar field vanishes. For an illustrative choice of nonminimal coupling, we scan the domain of existence. For each value of spin, SBHs exist in an interval between two critical masses, with the lowest one vanishing in the static limit. Non-uniqueness with Kerr BHs of equal global charges is observed; the SBHs are entropically favoured. This suggests that SBHs form dynamically from the spontaneous scalarization of Kerr BHs, which are prone to a scalar-triggered tachyonic instability, below the largest critical mass. Phenomenologically, the introduction of BH spin damps the maximal observable difference between comparable scalarized and vacuum BHs. In the static limit, (perturbatively stable) SBHs can store over 20% of the spacetime energy outside the event horizon; in comparison with Schwarzschild BHs, their geodesic frequency at the ISCO can differ by a factor of 2.5 and deviations in the shadow areal radius may top 40%. As the BH spin grows, low mass SBHs are excluded, and the maximal relative differences decrease, becoming of the order of a few percent for dimensionless spin j≳0.5. This reveals a spin selection effect: non-GR effects are only significant for low spin. We discuss if and how the recently measured shadow size of the M87 supermassive BH constrains the length scale of the Gauss-Bonnet coupling.
Event studies: A methodology review Corrado, Charles J.
Accounting and finance (Parkville),
March 2011, Volume:
51, Issue:
1
Journal Article
Peer reviewed
Originally developed as a statistical tool for empirical research in accounting and finance, event studies have since migrated to other disciplines as well, including economics, history, law, ...management, marketing, and political science. Despite the elegant simplicity of a standard event study, variations in methodology and their relative merits continue to attract attention in the literature. This paper reviews some of the fundamental topics in short‐term event study methodology, with an attempt to add new perspectives to some pressing topics.
Empathy is essential for the survival of social species. In many studies, especially those with animal models, empathy for pain was evaluated by the modulation of pain sensitivity. However, the ...relationship between pain sensitivity and empathy for pain is not well established. Here, by performing two experiments, we aimed to investigate their relationship at both behavioral and electrophysiological levels. In Experiment 1, we characterized individual pain sensitivity using pain threshold and tolerance in a cold pressor test, self‐report empathy using Interpersonal Reactivity Index, and pain‐related psychological factors, including pain‐related anxiety, depression, pain catastrophizing, and pain‐related fear, using well‐validated questionnaires. We observed that pain sensitivity was positively correlated with emotional empathy, and their relationship was mediated by pain‐related anxiety, pain catastrophizing, and pain‐related fear. In Experiment 2, we quantified empathy for pain using pain intensity and unpleasantness as well as event‐related potentials (ERPs) in an empathy for pain task. Positive correlations were observed between pain sensitivity and psychophysiological empathic responses (i.e., the P3 component and the late positive potential in ERPs), and their relationship was mediated by pain‐related fear. These results suggested that being influenced by some pain‐related psychological factors, individuals with higher pain sensitivity tended to have stronger empathy for pain, manifested as stronger emotional reactions to others' pain. Our results indicated that the conventional strategy of using pain sensitivity to quantify empathy should be treated with caution, as their relationship could be disturbed by experimental manipulations or pathological modulations that could influence individual emotional states or cognitive processes.
•A new event-triggered sampling scheme for filtering of switched systems is proposed.•A filtering model based on event-triggered sampled data of both the system output and the system mode is ...developed.•The weighted H∞ performance analysis result for the filtering error systems is obtained.
This paper considers the event-triggered H∞ filtering problem for continuous-time switched linear systems. It is assumed that only the information of system output and switching signal is available to the filter at each event-triggered sampling instant. Based on a mode dependent event-triggered sampling scheme, the filtering error system is modeled as a switched system with augmented switching signal. Then, by the average dwell time technique and multiple Lyapunov function method, a new sufficient condition is obtained such that the filtering error system is exponentially asymptotically stable and satisfies the weighted H∞ performance. The design method for the filter and event-triggered parameters is formulated by solving a set of linear matrix inequalities. Finally, the effectiveness of the proposed approach is illustrated by two numerical examples.
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