A Fully-Automatic Gap Filling Approach for Motion Capture Trajectories

Missing marker information is a common problem in Motion Capture (MoCap) systems. Commercial MoCap software provides several methods for reconstructing incomplete marker trajectories; however, these methods still rely on manual intervention. Current alternatives proposed in the literature still present drawbacks that prevent their widespread adoption. The lack of fully automated and universal solutions for gap filling is still a reality. We propose an automatic frame-wise gap filling routine that simultaneously explores restrictions between markers’ distance and markers’ dynamics in a least-squares minimization problem. This algorithm constitutes the main contribution of our work by simultaneously overcoming several limitations of previous methods that include not requiring manual intervention, prior training or training data; not requiring information about the skeleton or a dedicated calibration trial and by being able to reconstruct all gaps, even if these are located in the initial and final frames of a trajectory. We tested our approach in a set of artificially generated gaps, using the full body marker set, and compared the results with three methods available in commercial MoCap software: spline, pattern and rigid body fill. Our method achieved the best overall performance, presenting lower reconstruction errors in all tested conditions.

Information Application of the Regional Development: Strategic Couplings in Global Production Networks in Jiangsu, China

The recent literature concerning globalizing regional development has placed significant emphasis on the Global Production Network (GPN 2.0). GPN 2.0 in economic geography emphasizes that regional growth is caused by a shift in the strategic coupling mode from a low to high level. In addition, GPN 2.0 regards firm-level value capture trajectories as key analytical object, rather than the interactive relationships among scalar and divergent actors in GPN 1.0. To provide a better understanding of causal linkages between the GPNs and uneven regional development in the background of globalization and to test the applicability of GPN 2.0 analysis framework, the paper analyzed 62 Korean-invested automotive firms in Jiangsu Province, China. In order to explore the value capture trajectories of lead firms in the GPNs, the authors applied K-means clustering method to quantitatively analyze the local supply networks of lead firms from organizational and spatial dimensions. Then, comparisons were made between strategic coupling modes of GPNs and regional development in North and South Jiangsu. This study found obvious similarities within these two regions but obvious differences between them in terms of value capture trajectories. We observed that North Jiangsu is currently in the stage of “structural coupling”, whereas South Jiangsu is in the stage of “functional coupling.” Thus, this article argues that spatial settings such as regional assets and autonomy are key factors influencing uneven economic development. This research may provide a crucial reference for the regional development of Jiangsu, China.

Lagrangian coherent structures in the planar parabolic/hyperbolic restricted three-body problem

ABSTRACT It is clarified that the parabolic/hyperbolic restricted three-body problem (PRTBP/HRTBP) can be adopted to provide a simple description of the dynamics of fly-by asteroids or the close encounters between different galaxies. For these reasons, PRTBP and HRTBP have been investigated for long intervals of time. However, they are quite different from the circular restricted three-body problem due to the time-dependent and non-periodic dynamics. The Lagrangian coherent structures (LCSs), as a useful tool to analyse the time-dependent dynamical system, could be applied to explain some mechanics of the PRTBP and HRTBP. In this paper, we verify the invariant manifolds on the boundary manifolds of PRTBP by analysing the LCSs in proper Poincaré sections, which shows that it works in such a non-periodic problem. One of the contributions is to investigate the LCSs in the complete phase space of PRTBP, and then some natural escape and capture trajectories from or to the two main bodies can be obtained in this way. Another contribution is to establish and study the dynamics of HRTBP and its boundary. The LCSs can be introduced into this system, reasonably, to work as the analogues of the invariant manifolds, and the similar natural escape and capture trajectories corresponding to the two main bodies can also be obtained in the complete phase space of HRTBP. As a typical technique applied to fluid, flows to identify transport barriers in the time-dependent system, the LCSs provide an effective way to determine the time-dependent analogues of invariant manifolds for the PRTBP/HRTBP.

Beyond the Aggregate Score: Using Multilevel Modeling to Examine Trajectories of Laboratory-Measured Aggression

Aggression is often measured in the laboratory as an iterative ‘tit-for-tat’ sequence, in which two aggressors repeatedly inflict retaliatory harm upon each other. Aggression researchers typically quantify aggression by aggregating across participants’ aggressive behavior on such iterative encounters. However, this ‘aggregate approach’ cannot capture trajectories of aggression across the iterative encounters and needlessly eliminates rich information in the form of within-participant variability. As an alternative approach, I employed multilevel modeling to examine the slope of aggression across the 25-trial Taylor Aggression Paradigm (TAP) as a function of trait physical aggression and experimental provocation. Across two preregistered studies (combined N = 392), participants exhibited a modest decline in aggression. This decline reflected a reciprocal strategy, in which participants responded to an initially-provocative opponent with greater aggression that then decreased over time in order to matched their opponent’s declining levels of aggression. Against predictions, trait physical aggression and experimental provocation did not affect participants’ overall trajectories of aggression. Yet exploratory analyses suggested that participants’ tendency to reciprocate their opponent’s aggression with more aggression was greater at higher levels of trait physical aggression and attenuated among participants who had already been experimentally-provoked by their opponent. These findings (a) illustrate several advantages of a multilevel modeling approach as compared to an aggregate approach to iterative laboratory aggression paradigms, (b) demonstrate that the magnifying effects of trait aggression and experimental provocation on laboratory aggression are stable over brief time-frames, and (c) suggest that modeling the opponent’s behavior on such tasks reveals important information.

Longitudinal Trajectories of Emotions in Four Dimensions Through Language Advisory Sessions

Through advising in language learning, this study describes two Japanese secondary school students’ (Ai and Yu: both pseudonyms) longitudinal trajectories of socioculturally mediated emotions in four dimensions. To investigate types of emotions, the research integrates multiple qualitative methods and Plutchik’s wheel of emotions, thus acknowledging both contextually complex and longitudinally dynamic aspects of emotions. Throughout a year of 19 advisory sessions, the amount of time spent was 1,263 minutes (Ai’s 12 sessions = 891 minutes; Yu’s 7 sessions = 372 minutes), and the number of emotional incidences identified was 358 (201 for Ai; 157 for Yu). Among multiple findings, the most notable was that both participants experienced convergence of emotions: the one process from diversified to less diversified emotions was caused by longitudinal dynamics of emotions in Ai’s case and by contextual complexity of emotions in Yu’s case. The study concludes by suggesting a tentative four-dimensional model of emotions to capture trajectories of advisees’ emotions from multiple perspectives. This model can help advisors to understand advisees’ emotionality and, therefore, to implement emotional support appropriately and continuously.