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"Pedal"
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Pedal and negative pedal surfaces of framed curves in the Euclidean 3-space
We define pedal and negative pedal surfaces of framed curves in the Euclidean 3-space and find that the loci of singularities of them are pedal and negative pedal curves, respectively. Moreover, we give sufficient conditions that pedal and negative pedal surfaces to be framed base surfaces. We also give a sufficient condition that negative pedal curves to be framed base curves.
Journal Article
Influence of pedal characteristics on pedaling control and neural drive in older adults
This study was aimed to investigate whether pedal characteristics and age affect pedal position accuracy, fluctuation, and neural drive variability during a position control task. Twelve older (age: 72.8 ± 3.6 years) and twelve young (age: 23.8 ± 4.4 years) adults performed trapezoidal position control tasks involving holding plantar flexor contraction for 10 s with four pedal conditions (regular and pulley types × standard and low forces). Neural drive of the triceps surae muscle was estimated with high-density surface electromyograms and individual motor unit decomposition methods. The central 5 s of the sustained contraction phase was used for analysis. Variabilities of the angle and neural drive are presented by the coefficient of variation. We observed that the angle fluctuation was greater in older than young adults for four pedal conditions (p < 0.05). Regardless of age, using pulley pedals increased angle fluctuation more than regular pedals (p < 0.05). No significant interaction was found for pedal conditions and age in pedal position accuracy, angle fluctuation, or neural output. Our results suggest that older adults have poor control ability to maintain pedal angles, and pulley pedals make it difficult to adjust the pedal angles regardless of age. However, the neural output estimated by the continuously active motor units failed to explain these differences.
Journal Article
A novel chaotic Runge Kutta optimization algorithm for solving constrained engineering problems
This study proposes a novel hybrid metaheuristic optimization algorithm named chaotic Runge Kutta optimization (CRUN). In this study, 10 diverse chaotic maps are being incorporated with the base Runge Kutta optimization (RUN) algorithm to improve their performance. An imperative analysis was conducted to check CRUN’s convergence proficiency, sustainability of critical constraints, and effectiveness. The proposed algorithm was tested on six well-known design engineering tasks, namely: gear train design, coupling with a bolted rim, pressure vessel design, Belleville spring, and vehicle brake-pedal optimization. The results demonstrate that CRUN is superior compared to state-of-the-art algorithms in the literature. So, in each case study, CRUN was superior to the rest of the algorithms and furnished the best-optimized parameters with the least deviation. In this study, 10 chaotic maps were enhanced with the base RUN algorithm. However, these chaotic maps improve the solution quality, prevent premature convergence, and yield the global optimized output. Accordingly, the proposed CRUN algorithm can also find superior aspects in various spectrums of managerial implications such as supply chain management, business models, fuzzy circuits, and management models.
Journal Article
Metatarsophalangeal proportions of
Post-cranial differences between extant apes and humans include differences in the length, shape and size of bone elements relative to each other; i.e. differences in proportions. Foot proportions are influenced by the different functional requirements of climbing and bipedal locomotion. Phalangeal length is generally correlated with locomotor behaviour in primates and there is variation in hominins in relative phalangeal lengths – the functional and evolutionary significance of which is unclear and currently debated. Homo naledi has a largely modern rearfoot (i.e. tarsal skeleton) and midfoot (i.e. metatarsal skeleton). The proximal pedal phalanges of H. naledi are curved, but the relative lengths are unknown, because the phalanges cannot reliably be associated with metatarsals, or in many cases even with ray number. Here, we assess the lengths of the proximal pedal phalanges relative to the metatarsals in H. naledi with resampling from modern human and chimpanzee (Pan troglodytes) samples. We use a novel resampling method that employs two boundary conditions, assuming at one extreme that elements in the sample are associated, and at the other extreme that no elements are associated. The associated metatarsophalangeal proportions from digits 1 and 2 are within the 95% confidence interval of the modern human distribution. However, the associated and unassociated proportions from digits 3–5 fall above the 95% confidence interval of the human distribution, but below and outside of the chimpanzee distribution. While these results may indicate fossil preservation bias or other sample-derived statistical limitations, they potentially raise the intriguing possibility of unique medial versus lateral pedal column functional evolution in H. naledi. Additionally, the relevant associated proportions of H. naledi are compared to and are different from those of H. floresiensis. Both species suggest deep phylogenetic placement so the ancestral condition of the pedal phalanges in the genus Homo remains unclear. Significance: • Modern humans demonstrate straight and relatively short pedal phalanges, whereas H. naledi demonstrates curved phalanges of an unknown relative length. This research analyses the relative length of the proximal phalanges to the metatarsals to determine if H. naledi has relatively short phalanges similar to modern humans or is distinct from modern humans in both its phalangeal length and curvature. • This analysis further develops a statistical resampling method that was previously applied to large fossil assemblages with little association between bones. • A more comprehensive understanding of pedal morphology of H. naledi could provide insight into the ancestral pedal form of the genus Homo as the overall morphology of H. naledi appears to be deeply rooted in the genus.
Journal Article
Methodology to Analyse Three-Dimensional Asymmetries in the Forces Applied to the Pedals in Cycling
The asymmetries study between both legs of the forces applied to the pedals in cycling is important because they may affect the performance of the cyclist or prevent the occurrence of injuries. Studies focused on analysing asymmetries in forces tend to consider only the effective force, disregarding the three-dimensional nature of the force. Furthermore, these studies do not analyse the possible physical or neurological causes that may have led to the appearance of the asymmetries. This paper presents a methodology to carry out three-dimensional analysis of the asymmetries of the forces applied in both pedals and discriminate the possible sources of these asymmetries. Seven participants, amateurs and without pathologies, were analysed. Two commercial pedals were instrumented to measure the three components of the force applied to each pedal. The Normalized Symmetry Index (NSI) and the Cross Correlation Coefficient (CCC) were used for the asymmetries analysis. Results showed that both indexes need to be used in conjunction to analyse the causes of asymmetry in the pedal forces from a 3D perspective along the pedal cycle. The NSI is an index that makes it possible to evaluate asymmetry by considering only the value of the force applied by each leg at each instant. The CCC makes it possible to evaluate whether the temporal evolutions of the forces applied by each leg are similar. Preliminary results suggest that the proposed methodology is effective for analysing asymmetries in the forces in a pedalling cycle from a three-dimensional point of view. Forces in the sagittal plane showed a high level of symmetry. The lateral-medial force presented the highest level of asymmetry due to the difference in the magnitudes of the applied forces by both legs and the existing time shift between the two force patterns. The results of this work will allow for more complete and accurate three-dimensional dynamic analyses of the lower body during pedalling.
Journal Article
Effect of pedaling cadence on muscle oxygenation during high-intensity cycling until exhaustion: a comparison between untrained subjects and triathletes
Purpose
The aim of this study was to compare the muscle oxygenation between trained and untrained subjects during heavy exercise until exhaustion at two extreme pedaling cadences using a NIRS system.
Methods
Nine untrained male subjects and nine male competitive triathletes cycled until exhaustion at an intensity corresponding to 90 % of the power output achieved at peak oxygen uptake at 40 and 100 rpm. Gas exchanges were measured breath-by-breath during each exercise. Muscle (de)oxygenation was monitored continuously by near-infrared spectroscopy on the
Vastus Lateralis
.
Results
Muscle deoxygenation (∆deoxy[Hb + Mb], i.e., O
2
extraction) and ∆total[Hb + Mb] were significantly higher at 40 rpm compared to 100 rpm during the exercise in untrained subjects but not in triathletes (
p
< 0.05). The time performed until exhaustion was significantly higher at 40 than at 100 rpm in untrained subjects (373 ± 55 vs. 234 ± 37 s, respectively) but not in triathletes (339 ± 69 vs. 325 ± 66 s).
Conclusions
These results indicate that high aerobic fitness (1) allows for better regulation between
V
˙
O
2
M
and
Q
˙
O
2
M
following the change in pedaling cadence, and (2) is the most important factor in the relationship between pedaling cadence and performance.
Journal Article
WORMESH-I: Introducing a Robot Concept Bio-Inspired by Flatworms, Developing a Mechanical Model, and Creating Locomotion via Pedal Waves
Flatworms exhibit remarkable pedal-wave-driven locomotion abilities through their dorsoventrally flattened, bilaterally symmetrical bodies, which glide smoothly across various surfaces. This study introduces a bio-inspired mobile robot prototype designed to mimic flatworm movement that leverage the advantages of pedal locomotion on challenging terrains. The robot design includes a mesh-like structure with interconnected body modules linked via multi-degree-of-freedom joints for enhanced movement versatility. A modified universal joint that functions as a constant-velocity joint connects the modules, thereby enabling complex motion patterns. We explored four types of traveling waves, inspired by gastropod locomotion to achieve diverse movements, including translational, spinning, and omnidirectional motions. This study comprehensively examines the movement characteristics and performance of the prototype, highlighting its potential applications in complex environments in which traditional locomotion methods are less effective.
Journal Article
Towards an automated decision support system for the identification of additive manufacturing part candidates
As additive manufacturing (AM) continues to mature, an efficient and effective method to identify parts which are eligible for AM as well as gaining insight on what values it may add to a product is needed. Prior methods are naturally developed and highly experience-dependent, which falls short for its objectiveness and transferability. In this paper, a decision support system (DSS) framework for automatically determining the candidacy of a part or assembly for AM applications is proposed based on machine learning (ML) and carefully selected candidacy criteria. With the goal of supporting efficient candidate screening in the early conceptual design stage, these criteria are further individually decoded to decisive parameters which can be extracted from digital models or resource planning databases. Over 200 existing industrial examples are manually collected and labelled as training data; meanwhile, multiple regression algorithms are tested against each AM potential to find better predictive performance. The proposed DSS framework is implemented as a web application with integrated cloud-based database and ML service, which allows advantages of easy maintenance, upgrade, and retraining of ML models. Two case studies of a hip implant and a throttle pedal are used as demonstrating examples. This preliminary work provides a promising solution for lowering the requirements of non-AM experts to find suitable AM candidates.
Journal Article
