Corrigendum to “Applying circular statistics can cause artefacts in the calculation of vector coding variability: A bivariate solution” [Gait Posture 65 (2018) 51–56]

2019 ◽  
Vol 71 ◽  
pp. 296
Author(s):  
Holly Stock ◽  
Richard van Emmerik ◽  
Cassie Wilson ◽  
Ezio Preatoni
Keyword(s):  
Circular Statistics ◽  
Vector Coding ◽  
Gait Posture

Applying circular statistics can cause artefacts in the calculation of vector coding variability: A bivariate solution

2018 ◽  
Vol 65 ◽  
pp. 51-56 ◽  
Author(s):  
Holly Stock ◽  
Richard van Emmerik ◽  
Cassie Wilson ◽  
Ezio Preatoni
Keyword(s):  
Circular Statistics ◽  
Vector Coding

Comparisons of Segment Coordination: An Investigation of Vector Coding

2018 ◽  
Vol 34 (3) ◽  
pp. 226-231 ◽  
Author(s):  
Julia Freedman Silvernail ◽  
Richard E.A. van Emmerik ◽  
Katherine Boyer ◽  
Michael A. Busa ◽  
Joseph Hamill
Keyword(s):  
Linear Analysis ◽  
Circular Data ◽  
Circular Statistics ◽  
Coordination Pattern ◽  
Movement Coordination ◽  
Vector Coding ◽  
Movement Organization ◽  
Coordination Patterns ◽  
Compressed Data ◽  
Group Comparisons

The development of a methodology to assess movement coordination has provided gait researchers a tool to assess movement organization. A challenge in analyzing movement coordination using vector coding lies within the inherent circularity of data garnered from this technique. Therefore, the purpose of this investigation was to determine if accurate group comparisons can be made with varying techniques of vector coding analyses. Thigh–shank coordination was analyzed using a modified vector coding technique on data from 2 groups of runners. Movement coordination was compared between groups using 3 techniques: (1) linear average completed with compressed data (0°–180°) and noncompressed data (0°–360°), (2) coordination phase binning analysis; and (3) a circular statistics analysis. Circular statistics (inferential) analysis provided a rigorous comparison of average movement coordination between groups. In addition, the binning analysis provided a metric for detecting even small differences in the time spent with a particular coordination pattern between groups. However, the linear analysis provided erroneous group comparisons. Furthermore, with compressed data, linear analysis led to misclassification of coordination patterns. While data compression may be attractive as a means of simplifying statistical analysis of inherently circular data, recommendations are to use circular statistics and binning methods on noncompressed data.

scholarly journals Coordination Pattern of the Thigh, Pelvic, and Lumbar Movements during the Gait of Patients with Hip Osteoarthritis

2020 ◽  
Vol 2020 ◽  
pp. 1-9
Author(s):  
Takuya Ibara ◽  
Masaya Anan ◽  
Ryosuke Karashima ◽  
Kiyotaka Hada ◽  
Koichi Shinkoda ◽  
...  
Keyword(s):  
Time Series Data ◽  
Hip Osteoarthritis ◽  
Series Data ◽  
Measurement Unit ◽  
Control Group ◽  
Coordination Pattern ◽  
Rotational Movement ◽  
Vector Coding ◽  
Lateral Tilt ◽  
Angular Velocities

There are limited reports on segment movement and their coordination pattern during gait in patients with hip osteoarthritis. To avoid the excessive stress toward the hip and relevant joints, it is important to investigate the coordination pattern between these segment movements, focusing on the time series data. This study aimed to quantify the coordination pattern of lumbar, pelvic, and thigh movements during gait in patients with hip osteoarthritis and in a control group. An inertial measurement unit was used to measure the lumbar, pelvic, and thigh angular velocities during gait of 11 patients with hip osteoarthritis and 11 controls. The vector coding technique was applied, and the coupling angle and the appearance rate of coordination pattern in each direction were calculated and compared with the control group. Compared with the control group, with respect to the lumbar/pelvic segment movements, the patients with hip osteoarthritis spent more rates in anti-phase and lower rates in in-phase lateral tilt movement. With respect to the pelvic/thigh segment movements, the patients with hip osteoarthritis spent more rates within the proximal- and in-phases for lateral tilt movement. Furthermore, patients with osteoarthritis spent lower rates in the distal-phase for anterior/posterior tilt and rotational movement. Patients with hip osteoarthritis could not move their pelvic and thigh segments separately, which indicates the stiffness of the hip joint. The rotational movement and lateral tilt movements, especially, were limited, which is known as Duchenne limp. To maintain the gait ability, it seems important to pay attention to these directional movements.

scholarly journals Evaluation of Human Disturbance on the Activity of Medium–Large Mammals in Myanmar Tropical Forests

Forests ◽  
2021 ◽  
Vol 12 (3) ◽  
pp. 290
Author(s):  
Giacomo Cremonesi ◽  
Francesco Bisi ◽  
Lorenzo Gaffi ◽  
Thet Zaw ◽  
Hla Naing ◽  
...  
Keyword(s):  
Human Disturbance ◽  
Daily Activity ◽  
Wildlife Conservation ◽  
Activity Patterns ◽  
Circular Statistics ◽  
Large Mammals ◽  
Human Presence ◽  
Significant Difference ◽  
The Status ◽  
Statistical Approaches

The effects of human disturbance represent one of the major threats for wildlife conservation. Many studies have shown that wildlife avoids or reduces direct contact with human activities through changes in activity patterns, and by minimizing spatiotemporal overlap. In this study, we investigated the possible effects of human presence on the temporal activity of medium-to-large mammals using two areas in Myanmar that differ in the intensity of human disturbance. We monitored temporal segregation mechanisms using camera trapping data and with two statistical approaches: daily activity overlaps between humans and wildlife and circular statistics. We did not find a significant difference in overlapping activity between areas but, thanks to circular statistics, we found that some species show changes in activity patterns, suggesting temporal avoidance. We observed that the daily activity of five species differed between areas of Myanmar, likely adopting mechanisms to reduce overlap in areas highly frequented by humans. Interestingly, these species are all threatened by hunting or poaching activities, four of which have been described in literature as “cathemeral”, or species that are active through day and night. This study suggests that some species adapt their behavior, at least partially, to avoid human presence in habitats with higher anthropic occurrence and increase our knowledge on the status of medium–large mammals in a poorly studied country as Myanmar.

scholarly journals An Universal, Simple, Circular Statistics-Based Estimator of α for Symmetric Stable Family

2019 ◽  
Vol 12 (4) ◽  
pp. 171
Author(s):  
Ashis SenGupta ◽  
Moumita Roy
Keyword(s):  
Entire Range ◽  
Goodness Of Fit ◽  
Stable Distribution ◽  
Real Life ◽  
Circular Statistics ◽  
Directional Statistics ◽  
Symmetric Stable Distribution ◽  
Stable Family ◽  
Family Of Distributions ◽  
Better Than

The aim of this article is to obtain a simple and efficient estimator of the index parameter of symmetric stable distribution that holds universally, i.e., over the entire range of the parameter. We appeal to directional statistics on the classical result on wrapping of a distribution in obtaining the wrapped stable family of distributions. The performance of the estimator obtained is better than the existing estimators in the literature in terms of both consistency and efficiency. The estimator is applied to model some real life financial datasets. A mixture of normal and Cauchy distributions is compared with the stable family of distributions when the estimate of the parameter α lies between 1 and 2. A similar approach can be adopted when α (or its estimate) belongs to (0.5,1). In this case, one may compare with a mixture of Laplace and Cauchy distributions. A new measure of goodness of fit is proposed for the above family of distributions.

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