Control of dynamics via identical time-lagged stochastic inputs

2020 ◽  
Vol 30 (1) ◽  
pp. 013143 ◽  
Author(s):  
Ehsan Bolhasani ◽  
Yousef Azizi ◽  
Daryoush Abdollahpour ◽  
Jafar M. Amjad ◽  
Matjaž Perc
2020 ◽  
Vol 36 (3) ◽  
pp. 500-509
Author(s):  
Hannah G. Bosley ◽  
Devon B. Sandel ◽  
Aaron J. Fisher

Abstract. Generalized anxiety disorder (GAD) is associated with worry and emotion regulation difficulties. The contrast-avoidance model suggests that individuals with GAD use worry to regulate emotion: by worrying, they maintain a constant state of negative affect (NA), avoiding a feared sudden shift into NA. We tested an extension of this model to positive affect (PA). During a week-long ecological momentary assessment (EMA) period, 96 undergraduates with a GAD analog provided four daily measurements of worry, dampening (i.e., PA suppression), and PA. We hypothesized a time-lagged mediation relationship in which higher worry predicts later dampening, and dampening predicts subsequently lower PA. A lag-2 structural equation model was fit to the group-aggregated data and to each individual time-series to test this hypothesis. Although worry and PA were negatively correlated in 87 participants, our model was not supported at the nomothetic level. However, idiographically, our model was well-fit for about a third (38.5%) of participants. We then used automatic search as an idiographic exploratory procedure to detect other time-lagged relationships between these constructs. While 46 individuals exhibited some cross-lagged relationships, no clear pattern emerged across participants. An alternative hypothesis about the speed of the relationship between variables is discussed using contemporaneous correlations of worry, dampening, and PA. Findings suggest heterogeneity in the function of worry as a regulatory strategy, and the importance of temporal scale for detection of time-lagged effects.


2011 ◽  
Vol 29 (supplement) ◽  
pp. 283-304 ◽  
Author(s):  
Timothy R. Brick ◽  
Steven M. Boker

Among the qualities that distinguish dance from other types of human behavior and interaction are the creation and breaking of synchrony and symmetry. The combination of symmetry and synchrony can provide complex interactions. For example, two dancers might make very different movements, slowing each time the other sped up: a mirror symmetry of velocity. Examining patterns of synchrony and symmetry can provide insight into both the artistic nature of the dance, and the nature of the perceptions and responses of the dancers. However, such complex symmetries are often difficult to quantify. This paper presents three methods – Generalized Local Linear Approximation, Time-lagged Autocorrelation, and Windowed Cross-correlation – for the exploration of symmetry and synchrony in motion-capture data as is it applied to dance and illustrate these with examples from a study of free-form dance. Combined, these techniques provide powerful tools for the examination of the structure of symmetry and synchrony in dance.


Author(s):  
Subrata Roy

The present study seeks to examine the mutual fund performance of the open-ended selected equity schemes of UTI based on multi-index measures as well as conditional multi-index measure. It is observed from the analysis that multi-index measure is able to capture the beta and alpha effects on market adjusted basis and the estimated coefficients is a better representative as compared to the single index measure. When time lagged (lagged at 1 month, 2 months, quarterly and yearly) multi-index measures are applied then the estimated coefficients (alpha & beta) which are market adjusted and time adjusted look more representative than the multi-index measure (without lagged effect). Finally, when we extended the time lagged multi-index measure on a conditional way (conditional on public information variables) then we observe that conditional multi-index lagged measure provides much more representative results in all respects as compared to the all measures after conditioning public information effects.


2021 ◽  
Author(s):  
Marion Germain ◽  
Daniel Kneeshaw ◽  
Louis De Grandpré ◽  
Mélanie Desrochers ◽  
Patrick M. A. James ◽  
...  

Abstract Context Although the spatiotemporal dynamics of spruce budworm outbreaks have been intensively studied, forecasting outbreaks remains challenging. During outbreaks, budworm-linked warblers (Tennessee, Cape May, and bay-breasted warbler) show a strong positive response to increases in spruce budworm, but little is known about the relative timing of these responses. Objectives We hypothesized that these warblers could be used as sentinels of future defoliation of budworm host trees. We examined the timing and magnitude of the relationships between defoliation by spruce budworm and changes in the probability of presence of warblers to determine whether they responded to budworm infestation before local defoliation being observed by standard detection methods. Methods We modelled this relationship using large-scale point count surveys of songbirds and maps of cumulative time-lagged defoliation over multiple spatial scales (2–30 km radius around sampling points) in Quebec, Canada. Results All three warbler species responded positively to defoliation at each spatial scale considered, but the timing of their response differed. Maximum probability of presence of Tennessee and Cape May warbler coincided with observations of local defoliation, or provided a one year warning, making them of little use to guide early interventions. In contrast, the probability of presence of bay-breasted warbler consistently increased 3–4 years before defoliation was detectable. Conclusions Early detection is a critical step in the management of spruce budworm outbreaks and rapid increases in the probability of presence of bay-breasted warbler could be used to identify future epicenters and target ground-based local sampling of spruce budworm.


2021 ◽  
Vol 49 (1) ◽  
Author(s):  
N. D. B. Ehelepola ◽  
Kusalika Ariyaratne ◽  
A. M. S. M. C. M. Aththanayake ◽  
Kamalanath Samarakoon ◽  
H. M. Arjuna Thilakarathna

Abstract Background Leptospirosis is a bacterial zoonosis. Leptospirosis incidence (LI) in Sri Lanka is high. Infected animals excrete leptospires into the environment via their urine. Survival of leptospires in the environment until they enter into a person and several other factors that influence leptospirosis transmission are dependent upon local weather. Past studies show that rainfall and other weather parameters are correlated with the LI in the Kandy district, Sri Lanka. El Niño Southern Oscillation (ENSO), ENSO Modoki, and the Indian Ocean Dipole (IOD) are teleconnections known to be modulating rainfall in Sri Lanka. There is a severe dearth of published studies on the correlations between indices of these teleconnections and LI. Methods We acquired the counts of leptospirosis cases notified and midyear estimated population data of the Kandy district from 2004 to 2019, respectively, from weekly epidemiology reports of the Ministry of Health and Department of Census and Statistics of Sri Lanka. We estimated weekly and monthly LI of Kandy. We obtained weekly and monthly teleconnection indices data for the same period from the National Oceanic and Atmospheric Administration (NOAA) of the USA and Japan Agency for Marine-Earth Science and Technology (JAMSTEC). We performed wavelet time series analysis to determine correlations with lag periods between teleconnection indices and LI time series. Then, we did time-lagged detrended cross-correlation analysis (DCCA) to verify wavelet analysis results and to find the magnitudes of the correlations detected. Results Wavelet analysis displayed indices of ENSO, IOD, and ENSO Modoki were correlated with the LI of Kandy with 1.9–11.5-month lags. Indices of ENSO showed two correlation patterns with Kandy LI. Time-lagged DCCA results show all indices of the three teleconnections studied were significantly correlated with the LI of Kandy with 2–5-month lag periods. Conclusions Results of the two analysis methods generally agree indicating that ENSO and IOD modulate LI in Kandy by modulating local rainfall and probably other weather parameters. We recommend further studies about the ENSO Modoki and LI correlation in Sri Lanka. Monitoring for extreme teleconnection events and enhancing preventive measures during lag periods can blunt LI peaks that may follow.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Jie Zhu ◽  
Blanca Gallego

AbstractEpidemic models are being used by governments to inform public health strategies to reduce the spread of SARS-CoV-2. They simulate potential scenarios by manipulating model parameters that control processes of disease transmission and recovery. However, the validity of these parameters is challenged by the uncertainty of the impact of public health interventions on disease transmission, and the forecasting accuracy of these models is rarely investigated during an outbreak. We fitted a stochastic transmission model on reported cases, recoveries and deaths associated with SARS-CoV-2 infection across 101 countries. The dynamics of disease transmission was represented in terms of the daily effective reproduction number ($$R_t$$ R t ). The relationship between public health interventions and $$R_t$$ R t was explored, firstly using a hierarchical clustering algorithm on initial $$R_t$$ R t patterns, and secondly computing the time-lagged cross correlation among the daily number of policies implemented, $$R_t$$ R t , and daily incidence counts in subsequent months. The impact of updating $$R_t$$ R t every time a prediction is made on the forecasting accuracy of the model was investigated. We identified 5 groups of countries with distinct transmission patterns during the first 6 months of the pandemic. Early adoption of social distancing measures and a shorter gap between interventions were associated with a reduction on the duration of outbreaks. The lagged correlation analysis revealed that increased policy volume was associated with lower future $$R_t$$ R t (75 days lag), while a lower $$R_t$$ R t was associated with lower future policy volume (102 days lag). Lastly, the outbreak prediction accuracy of the model using dynamically updated $$R_t$$ R t produced an average AUROC of 0.72 (0.708, 0.723) compared to 0.56 (0.555, 0.568) when $$R_t$$ R t was kept constant. Monitoring the evolution of $$R_t$$ R t during an epidemic is an important complementary piece of information to reported daily counts, recoveries and deaths, since it provides an early signal of the efficacy of containment measures. Using updated $$R_t$$ R t values produces significantly better predictions of future outbreaks. Our results found variation in the effect of early public health interventions on the evolution of $$R_t$$ R t over time and across countries, which could not be explained solely by the timing and number of the adopted interventions.


2021 ◽  
pp. 105960112110199
Author(s):  
Nathapon Siangchokyoo ◽  
Ryan L. Klinger

This study explores how team core self-evaluations (CSE) influence the emergence and effectiveness of shared leadership. Drawing on adaptive leadership theory, we propose that decisions to share leadership responsibilities rather than allocating the role to a single team member are influenced by homogeneity in members’ CSE. In addition, we identify team collective identification as an emergent team state that interacts with CSE homogeneity to promote the emergence of shared leadership. We then argue that not all shared leadership teams are equally effective; applying group social capital theory, we propose that team mean CSE strengthens the impact of shared leadership on team performance. Results based on multisource and time-lagged data from 85 project teams provide support for our proposed moderated mediation model. We discuss how our theoretical model extends research on the role of team dispositional composition on the antecedents and consequents of shared leadership and highlight practical implications related to the design, recruitment, and socialization of autonomous work teams.


2021 ◽  
pp. 001872672110385
Author(s):  
Lu Xing ◽  
Jian-Min Sun ◽  
Denise Jepsen ◽  
Yejun Zhang

Why do some employees respond well to negative feedback, whereas others respond poorly? We suggest it depends on two factors: First, employees’ attribution of the feedback, or why employees believe their supervisor provides negative feedback in the first place, and second, employees’ core self-evaluation (CSE). These factors have implications for employees’ motivation to learn and learning performance. We tested our hypotheses using two three-wave time-lagged survey data from 370 employees in the United States (Study 1) and 302 hospital nurses in China (Study 2). Results suggest that for employees with high CSE, negative feedback is positively associated with the attribution that the feedback is given for performance-driven purposes (i.e., external attribution), which is in turn positively related to their motivation to learn. For employees with low CSE, negative feedback is positively related to the attribution that the feedback is given for self-serving purposes (i.e., internal attribution). Such attribution is negatively related to motivation to learn (Study 1), which further predicts the increase in their learning performance (Study 2). This study not only extends the theoretical understanding of negative feedback effectiveness, but also offers implications for supervisors to better deliver and for employees to better receive negative feedback.


Author(s):  
Xue Zhang ◽  
Liang Liang ◽  
Guyang Tian ◽  
Yezhuang Tian

Although prior research has emphasized the disproportional contributions to organizations of charismatic leadership, an emerging line of research has started to examine the potentially negative consequences. In this paper, a theoretical framework was proposed for a study of unethical pro-organization behavior through psychological safety based on social information processing theory, which reveals the detrimental effect that charismatic leadership can have on workplace behavior. To explore this negative possibility, a time-lagged research design was applied for the hypotheses to be verified using 214 pieces of data collected from a service company in China. According to the results, unethical pro-organizational behavior was indirectly influenced by charismatic leadership through psychological safety. Moreover, when employees experienced high performance pressure, charismatic leadership was positively associated with unethical pro-organizational behavior through psychological safety. The implications of these findings were analyzed from the perspectives of charismatic leadership theory and organizational ethical activities to alter the unethical pro-organizational behavior.


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