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1
Zhao, Kunkun, Zhisheng Zhang, Haiying Wen, Zihan Wang, and Jiankang Wu. "Modular Organization of Muscle Synergies to Achieve Movement Behaviors." Journal of Healthcare Engineering 2019 (November 15, 2019): 1–9. http://dx.doi.org/10.1155/2019/8130297.
Повний текст джерелаАнотація:
Muscle synergy has been applied to comprehend how the central nervous system (CNS) controls movements for decades. However, it is not clear about the motion control mechanism and the relationship between motions and muscle synergies. In this paper, we designed two experiments to corroborate the hypothesis: (1) motions can be decomposed to motion primitives, which are driven by muscle synergy primitives and (2) variations of motion primitives in direction and scale are modulated by activation coefficients rather than muscle synergy primitives. Surface electromyographic (EMG) signals were recorded from nine muscles of the upper limb. Nonnegative matrix factorization (NMF) was applied to extract muscle synergy vectors and corresponding activation coefficients. We found that synergy structures of different movement patterns were similar (α=0.05). The motion modulation indexes (MMI) among movement patterns in reaching movements showed apparent differences. Merging coefficients and reconstructed similarity of synergies between simple motions and complex motions were significant. This study revealed the motion control mechanism of the CNS and provided a rehabilitation and evaluation method for patients with motor dysfunction in exercise and neuroscience.
2
Luo, A. C. J., and Y. Guo. "Motion Switching and Chaos of a Particle in a Generalized Fermi-Acceleration Oscillator." Mathematical Problems in Engineering 2009 (2009): 1–40. http://dx.doi.org/10.1155/2009/298906.
Повний текст джерелаАнотація:
Dynamic behaviors of a particle (or a bouncing ball) in a generalized Fermi-acceleration oscillator are investigated. The motion switching of a particle in the Fermi-oscillator causes the complexity and unpredictability of motion. Thus, the mechanism of motion switching of a particle in such a generalized Fermi-oscillator is studied through the theory of discontinuous dynamical systems, and the corresponding analytical conditions for the motion switching are developed. From solutions of linear systems in subdomains, four generic mappings are introduced, and mapping structures for periodic motions can be constructed. Thus, periodic motions in the Fermi-acceleration oscillator are predicted analytically, and the corresponding local stability and bifurcations are also discussed. From the analytical prediction, parameter maps of periodic and chaotic motions are achieved for a global view of motion behaviors in the Fermi-acceleration oscillator. Numerical simulations are carried out for illustrations of periodic and chaotic motions in such an oscillator. In existing results, motion switching in the Fermi-acceleration oscillator is not considered. The motion switching for many motion states of the Fermi-acceleration oscillator is presented for the first time. This methodology will provide a useful way to determine dynamical behaviors in the Fermi-acceleration oscillator.
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Huang, Fan, Jun Huang, and Shao Bin Dai. "Chaotic Vibration of Fractional Calculus Model Viscoelastic Arch." Applied Mechanics and Materials 668-669 (October 2014): 151–55. http://dx.doi.org/10.4028/www.scientific.net/amm.668-669.151.
Повний текст джерелаАнотація:
Nonlinear dynamic behaviors of the fractional calculus model viscoelastic arch are discussed in this paper. The motion equations governing dynamic behaviors of the viscoelastic arch is derived and simplified by Galerkin method. The numerical method for solving the motion equations with fractional calculus is presented here. The influences of the load parameter and the material parameter are considered respectively. The results show that the chaotic vibration of the arch appears in forced vibration. And both the load parameter and the material parameter affect the dynamic behavior of the arch. With the increasing of the load parameter, the motion states changed from periodic motion with period 1 to complex motions, such as mult-periodicity, quasi-periodicity or chaos. The increasing of the material parameter benefits the stability of the structures.
4
Li, Jiaman, Jiajun Wu, and C. Karen Liu. "Object Motion Guided Human Motion Synthesis." ACM Transactions on Graphics 42, no. 6 (December 5, 2023): 1–11. http://dx.doi.org/10.1145/3618333.
Повний текст джерелаАнотація:
Modeling human behaviors in contextual environments has a wide range of applications in character animation, embodied AI, VR/AR, and robotics. In real-world scenarios, humans frequently interact with the environment and manipulate various objects to complete daily tasks. In this work, we study the problem of full-body human motion synthesis for the manipulation of large-sized objects. We propose Object MOtion guided human MOtion synthesis (OMOMO), a conditional diffusion framework that can generate full-body manipulation behaviors from only the object motion. Since naively applying diffusion models fails to precisely enforce contact constraints between the hands and the object, OMOMO learns two separate denoising processes to first predict hand positions from object motion and subsequently synthesize full-body poses based on the predicted hand positions. By employing the hand positions as an intermediate representation between the two denoising processes, we can explicitly enforce contact constraints, resulting in more physically plausible manipulation motions. With the learned model, we develop a novel system that captures full-body human manipulation motions by simply attaching a smartphone to the object being manipulated. Through extensive experiments, we demonstrate the effectiveness of our proposed pipeline and its ability to generalize to unseen objects. Additionally, as high-quality human-object interaction datasets are scarce, we collect a large-scale dataset consisting of 3D object geometry, object motion, and human motion. Our dataset contains human-object interaction motion for 15 objects, with a total duration of approximately 10 hours.
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Nomura, Tatsuya, and Kazuma Saeki. "Effects of Polite Behaviors Expressed by Robots." International Journal of Synthetic Emotions 1, no. 2 (July 2010): 38–52. http://dx.doi.org/10.4018/jse.2010070103.
Повний текст джерелаАнотація:
A psychological experiment was conducted to straightforwardly investigate the effects of polite behaviors expressed by robots in Japan, using a small-sized humanoid robot that performed four types of behaviors with voice task instructions. Results of the experiment suggested that the subjects who experienced “deep bowing” motion of the robot felt it more extrovert than those who experienced “just standing” motion. Subjects who experienced “lying” motion of the robot felt the robot less polite than those who experienced the other motions. Female subjects more strongly feeling the robot extrovert replied for the task instruction from the robot faster, although no such trend was found in the male subjects. However, the male subjects who did not perform the task felt the robot less polite than the male subjects who performed the task and the female subjects who did not perform the task.
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Rengifo, Carolina, Jean-Rémy Chardonnet, Hakim Mohellebi, Damien Paillot, and Andras Kemeny. "Driving simulator study of the relationship between motion strategy preference and self-reported driving behavior." SIMULATION 97, no. 9 (March 25, 2021): 619–33. http://dx.doi.org/10.1177/0037549721999716.
Повний текст джерелаАнотація:
Faithful motion restitution in driving simulators normally focuses on track monitoring and maximizing the platform workspace by leaving aside the principal component—the driver. Therefore, in this work we investigated the role of the motion perception model on motion cueing algorithms from a user’s viewpoint. We focused on the driving behavior influence regarding motion perception in a driving simulator. Participants drove a driving simulator with two different configurations: (a) using the platform dynamic model and (b) using a supplementary motion perception model. Both strategies were compared and the participants’ data were classified according to the strategy they preferred. To this end, we developed a driving behavior questionnaire aiming at evaluating the self-reported driving behavior influence on participants’ motion cueing preferences. The results showed significant differences between the participants who chose different strategies and the scored driving behavior in the hostile and violations factors. In order to support these findings, we compared participants’ behaviors and actual motion driving simulator indicators such as speed, jerk, and lateral position. The analysis revealed that motion preferences arise from different reasons linked to the realism or smoothness in motion. Also, strong positive correlations were found between hostile and violation behaviors of the group who preferred the strategy with the supplementary motion perception model, and objective measures such as jerk and speed on different road segments. This indicates that motion perception in driving simulators may depend not only on the type of motion cueing strategy, but may also be influenced by users’ self-reported driving behaviors.
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Chen, Xia, and Wenbo V. Li. "Limiting Behaviors for Brownian Motion Reflected on Brownian Motion." Methods and Applications of Analysis 9, no. 3 (2002): 377–92. http://dx.doi.org/10.4310/maa.2002.v9.n3.a5.
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Rui, Ying-Xu, Tie-Qiao Tang, and Jian Zhang. "An Improved Social Force Model for Bicycle Flow in Groups." Journal of Advanced Transportation 2021 (September 17, 2021): 1–14. http://dx.doi.org/10.1155/2021/2412655.
Повний текст джерелаАнотація:
Bicycle flow widely has group behavior (i.e., cyclists have a tendency to ride in groups), which may have some significant effects on the bicycle’s motion. However, the existing studies on bicycle flow rarely consider this factor. Generally, bicycle flow has two kinds of group behaviors, i.e., shoulder group behavior and following group behavior. In this paper, we propose an improved social force (SF) model to describe the two kinds of group behaviors. Then, we use the improved SF model to, respectively, explore the effects of the two kinds of group behaviors on the bicycle’s motion from the simulation perspective. The numerical results show that (i) shoulder group behavior has some negative impacts on the bicycle’s motion, i.e., the critical density (where the through capacity can reach the maximum value), the jam density, and the through capacity will be reduced; (ii) following group behavior has some positive impacts on the bicycle’s motion, i.e., the critical density, the jam density, and the through capacity will be enhanced; (iii) the impacts of coexistence of shoulder and following group behavior are related to the density. Besides, increasing group size and group probability will enlarge the negative impacts of shoulder group behavior and alleviate the positive impacts of following group behavior. These results can guide administrators to better manage bicycle flow (especially reasonably control the negative impacts of group behaviors).
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Horswill, Ian. "Lightweight Procedural Animation with Believable Physical Interactions." Proceedings of the AAAI Conference on Artificial Intelligence and Interactive Digital Entertainment 4, no. 1 (September 27, 2021): 48–53. http://dx.doi.org/10.1609/aiide.v4i1.18671.
Повний текст джерелаАнотація:
I describe a procedural animation system that uses techniques from behavior-based robot control, combined with a minimalist physical simulation, to produce believable character motions in a dynamic world. Although less realistic than motion capture or full biomechanical simulation, the system produces compelling, responsive character behavior. It is also fast, supports believable physical interactions between characters such as hugging, and makes it easy to author new behaviors.
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Wei, Yuan, and Jing Zhao. "Designing Human-like Behaviors for Anthropomorphic Arm in Humanoid Robot NAO." Robotica 38, no. 7 (September 30, 2019): 1205–26. http://dx.doi.org/10.1017/s026357471900136x.
Повний текст джерелаАнотація:
SUMMARYHuman-like motion of robots can improve human–robot interaction and increase the efficiency. In this paper, a novel human-like motion planning strategy is proposed to help anthropomorphic arms generate human-like movements accurately. The strategy consists of three parts: movement primitives, Bayesian network (BN), and a novel coupling neural network (CPNN). The movement primitives are used to decouple the human arm movements. The classification of arm movements improves the accuracy of human-like movements. The motion-decision algorithm based on BN is able to predict occurrence probabilities of the motions and choose appropriate mode of motion. Then, a novel CPNN is proposed to solve the inverse kinematics problems of anthropomorphic arms. The CPNN integrates different models into a single network and reflects the features of these models by changing the network structure. Through the strategy, the anthropomorphic arms can generate various human-like movements with satisfactory accuracy. Finally, the availability of the proposed strategy is verified by simulations for the general motion of humanoid NAO.
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Zhu, Wen Qiu, Qian Qian Li, Jun Feng Man, and Xiang Bing Wen. "Research on Human Behavior Recognition in Video Surveillance." Advanced Materials Research 255-260 (May 2011): 2276–80. http://dx.doi.org/10.4028/www.scientific.net/amr.255-260.2276.
Повний текст джерелаАнотація:
For effectively solving human behavior recognition in video surveillance, a novel behavior recognition model is presented. New behaviors may be produced in the process of human motion, hierarchical Dirichlet process is used to cluster monitored feature data of human body to decide whether unknown behaviors occur or not. The infinite hidden Markov model is used to learn unknown behavior patterns with supervised method, and then update the knowledge base. When knowledge base reaches a certain scale, the system can analyze human behaviors with unsupervised method. The Viterbi decoding algorithm of HMM is adopted to analyze current behavior of the human motion. The simulation experiments show that this method has unique advantage over others.
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Ooi, Sho, Tsuyoshi Ikegaya, and Mutsuo Sano. "Cooking Behavior Recognition Using Egocentric Vision for Cooking Navigation." Journal of Robotics and Mechatronics 29, no. 4 (August 20, 2017): 728–36. http://dx.doi.org/10.20965/jrm.2017.p0728.
Повний текст джерелаАнотація:
This paper presents a cooking behavior recognition method for achievement of a cooking navigation system. A cooking navigation system is a system that recognizes the progress of a user in cooking, and accordingly presents an appropriate recipe, thus supporting the activity. In other words, an appropriate recognition of cooking behaviors is required. Among the various cooking behavior recognition methods, such as the use of context with the object being focused on and use of information in the line of sight, we have so far attempted cooking behavior recognition using a method that focuses on the motion of arms. Using the cooking behavior rate obtained from the motion of arms and cooking utensils, this study achieves recognition of the cooking behavior. The average recognition rate was 63% when calculated by the conventional method of focusing on arm motions. It has been improved by approximately 20% by adding the proposed cooking utensil information and optimizing the parameters. An average recognition rate of 84% was achieved with respect to the five types of basic behaviors of “cut,” “peel,” “stir,” “add,” and “beat,” indicating the effectiveness of the proposed method.
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Zhou, Bochang, Jie Hu, Cheng Yuan, Weiping Wen, and Qingzhao Kong. "Permissible Scale Factors for Various Intensity Measures in Aftershock Ground Motion Scaling." Applied Sciences 13, no. 22 (November 20, 2023): 12515. http://dx.doi.org/10.3390/app132212515.
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This manuscript investigates the bias introduced by scaling aftershock ground motions when evaluating the performance of structures subjected to earthquake sequences. The study focuses on different hysteretic behaviors exhibited by structures and selects eight intensity measures as scale indicators. A benchmark database comprising 274 recorded mainshock–aftershock ground motions is utilized for analysis. The findings reveal that scaling aftershock records using intensity measures such as SI (seismic intensity), PGV (peak ground velocity), IC (Arias intensity), and Sa (spectral acceleration) relative to mainshock records effectively controls the mean bias within 30% throughout the entire period range, given a maximum scale factor of 10.0. However, it is observed that the additional damage in systems exhibiting un-degrading hysteretic behavior is more significantly affected by aftershock ground motion scaling compared to systems with degrading hysteretic behavior. Furthermore, scaling aftershock ground motions upwards using relative Sa tends to overestimate the additional damage incurred by structures. These results emphasize the importance of considering the specific hysteretic behavior of structures when applying aftershock ground motion scaling, as well as selecting appropriate intensity measures for accurate evaluation of structural performance.
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Bae, Sungryong, and Pilkee Kim. "Load Resistance Optimization of a Broadband Bistable Piezoelectric Energy Harvester for Primary Harmonic and Subharmonic Behaviors." Sustainability 13, no. 5 (March 6, 2021): 2865. http://dx.doi.org/10.3390/su13052865.
Повний текст джерелаАнотація:
In this study, optimization of the external load resistance of a piezoelectric bistable energy harvester was performed for primary harmonic (period-1T) and subharmonic (period-3T) interwell motions. The analytical expression of the optimal load resistance was derived, based on the spectral analyses of the interwell motions, and evaluated. The analytical results are in excellent agreement with the numerical ones. A parametric study shows that the optimal load resistance depended on the forcing frequency, but not the intensity of the ambient vibration. Additionally, it was found that the optimal resistance for the period-3T interwell motion tended to be approximately three times larger than that for the period-1T interwell motion, which means that the optimal resistance was directly affected by the oscillation frequency (or oscillation period) of the motion rather than the forcing frequency. For broadband energy harvesting applications, the subharmonic interwell motion is also useful, in addition to the primary harmonic interwell motion. In designing such piezoelectric bistable energy harvesters, the frequency dependency of the optimal load resistance should be considered properly depending on ambient vibrations.
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Xiao, Jizhong, Jun Xiao, and Ning Xi. "Intelligent Control of a Miniature Climbing Robot." Journal of Advanced Computational Intelligence and Intelligent Informatics 8, no. 3 (May 20, 2004): 260–68. http://dx.doi.org/10.20965/jaciii.2004.p0260.
Повний текст джерелаАнотація:
This paper presents an intelligent control system of a miniature climbing robot to achieve precise motion control, minimize power consumption, and produce versatile behaviors. The gravitational effects degrade the motion control performance and are difficult to compensate exactly, especially in the case of the climbing robot. A fuzzy logic based control scheme is developed which is capable of compensating the gravity at different robot configurations and task conditions. In order to reduce power consumption, an optimal control law is developed which minimizes the energy used to vacuum the suction foot. Primitive behaviors are implemented to provide the robot with basic competence. A finite state machine (FSM) is developed to synthesize signals from multiple sensors, keep track of robot motion status, and schedule motion sequences. FSM is an effective computational method in behavior-based control paradigm to implement robot behaviors. Experimental results prove the validity of the proposed methods.
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Pang, Xiao-Feng. "The nonlinear behaviors of movement of electron in the atoms." Modern Physics Letters B 29, no. 12 (May 10, 2015): 1550054. http://dx.doi.org/10.1142/s0217984915500542.
Повний текст джерелаАнотація:
In view of difficulties and questions of quantum mechanics in description of motion of electrons in hydrogen atom, we here established their nonlinear theory of motion based on the true motions of electron and nucleon and the real interactions between them, in which the motion of electron is depicted by a nonlinear Schrödinger equation with a Coulomb potential, the nonlinear interaction b∣φ∣2φ is produced by the change of Coulomb interaction between nucleon and electron due to the motion of nucleon. Thus the natures of the electron are thoroughly changed relative to those in quantum mechanics due to the nonlinear interactions, it not only is stable and localized, but also possesses a wave–corpuscle duality. Meanwhile, if its eigenenergy is still quantized and distributed in accordance with the energy levels, then we can use the new theory to explain perfectly the spectrum features of hydrogen atom, which resembles quantum mechanics, but its sizes of eigenenergy are depressed relative to that in quantum mechanics. This means that the nonlinear interaction enhances the localized and stable nature of the electron. Therefore, the new nonlinear theory is successful and correct to the hydrogen atom.
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Mirrazavi Salehian, Seyed Sina, Nadia Figueroa, and Aude Billard. "A unified framework for coordinated multi-arm motion planning." International Journal of Robotics Research 37, no. 10 (April 12, 2018): 1205–32. http://dx.doi.org/10.1177/0278364918765952.
Повний текст джерелаАнотація:
Coordination is essential in the design of dynamic control strategies for multi-arm robotic systems. Given the complexity of the task and dexterity of the system, coordination constraints can emerge from different levels of planning and control. Primarily, one must consider task-space coordination, where the robots must coordinate with each other, with an object or with a target of interest. Coordination is also necessary in joint space, as the robots should avoid self-collisions at any time. We provide such joint-space coordination by introducing a centralized inverse kinematics (IK) solver under self-collision avoidance constraints, formulated as a quadratic program and solved in real-time. The space of free motion is modeled through a sparse non-linear kernel classification method in a data-driven learning approach. Moreover, we provide multi-arm task-space coordination for both synchronous or asynchronous behaviors. We define a synchronous behavior as that in which the robot arms must coordinate with each other and with a moving object such that they reach for it in synchrony. In contrast, an asynchronous behavior allows for each robot to perform independent point-to-point reaching motions. To transition smoothly from asynchronous to synchronous behaviors and vice versa, we introduce the notion of synchronization allocation. We show how this allocation can be controlled through an external variable, such as the location of the object to be manipulated. Both behaviors and their synchronization allocation are encoded in a single dynamical system. We validate our framework on a dual-arm robotic system and demonstrate that the robots can re-synchronize and adapt the motion of each arm while avoiding self-collision within milliseconds. The speed of control is exploited to intercept fast moving objects whose motion cannot be predicted accurately.
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Kim, Nam Hee, Hung Yu Ling, Zhaoming Xie, and Michiel van de Panne. "Flexible Motion Optimization with Modulated Assistive Forces." Proceedings of the ACM on Computer Graphics and Interactive Techniques 4, no. 3 (September 22, 2021): 1–25. http://dx.doi.org/10.1145/3480144.
Повний текст джерелаАнотація:
Animated motions should be simple to direct while also being plausible. We present a flexible keyframe-based character animation system that generates plausible simulated motions for both physically-feasible and physically-infeasible motion specifications. We introduce a novel control parameterization, optimizing over internal actions, external assistive-force modulation, and keyframe timing. Our method allows for emergent behaviors between keyframes, does not require advance knowledge of contacts or exact motion timing, supports the creation of physically impossible motions, and allows for near-interactive motion creation. The use of a shooting method allows for the use of any black-box simulator. We present results for a variety of 2D and 3D characters and motions, using sparse and dense keyframes. We compare our control parameterization scheme against other possible approaches for incorporating external assistive forces.
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Mazzoni, Alberto, Elizabeth Garcia-Perez, Davide Zoccolan, Sergio Graziosi, and Vincent Torre. "Quantitative Characterization and Classification of Leech Behavior." Journal of Neurophysiology 93, no. 1 (January 2005): 580–93. http://dx.doi.org/10.1152/jn.00608.2004.
Повний текст джерелаАнотація:
This paper describes an automatic system for the analysis and classification of leech behavior. Three colored beads were attached to the dorsal side of a free moving or pinned leech, and color CCD camera images were taken of the animal. The leech was restrained to moving in a small tank or petri dish, where the water level can be varied. An automatic system based on color processing tracked the colored beads over time, allowing real-time monitoring of the leech motion for several hours. At the end of each experimental session, six time series (2 for each bead) describing the leech body motion were obtained. A statistical analysis based on the speed and frequency content of bead motion indicated the existence of several stereotypical patterns of motion, corresponding to different leech behaviors. The identified patterns corresponded to swimming, pseudo-swimming, crawling, exploratory behavior, stationary states, abrupt movements, and combinations of these behaviors. The automatic characterization of leech behavior demonstrated here represents an important step toward understanding leech behavior and its properties. This method can be used to characterize the behavior of other invertebrates and also for some small vertebrates.
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Khoramshahi, Mahdi, and Aude Billard. "A dynamical system approach for detection and reaction to human guidance in physical human–robot interaction." Autonomous Robots 44, no. 8 (July 26, 2020): 1411–29. http://dx.doi.org/10.1007/s10514-020-09934-9.
Повний текст джерелаАнотація:
Abstract A seamless interaction requires two robotic behaviors: the leader role where the robot rejects the external perturbations and focuses on the autonomous execution of the task, and the follower role where the robot ignores the task and complies with human intentional forces. The goal of this work is to provide (1) a unified robotic architecture to produce these two roles, and (2) a human-guidance detection algorithm to switch across the two roles. In the absence of human-guidance, the robot performs its task autonomously and upon detection of such guidances the robot passively follows the human motions. We employ dynamical systems to generate task-specific motion and admittance control to generate reactive motions toward the human-guidance. This structure enables the robot to reject undesirable perturbations, track the motions precisely, react to human-guidance by providing proper compliant behavior, and re-plan the motion reactively. We provide analytical investigation of our method in terms of tracking and compliant behavior. Finally, we evaluate our method experimentally using a 6-DoF manipulator.
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Li, Chaofeng, Qiansheng Tang, and Bangchun Wen. "Nonlinear Dynamic Behavior Analysis of Pressure Thin-Wall Pipe Segment with Supported Clearance at Both Ends." Mathematical Problems in Engineering 2016 (2016): 1–22. http://dx.doi.org/10.1155/2016/5432516.
Повний текст джерелаАнотація:
An analysis of nonlinear behaviors of pressure thin-wall pipe segment with supported clearance at both ends was presented in this paper. The model of pressure thin-wall pipe segment with supported clearance was established by assuming the restraint condition as the work of springs in the deformation directions. Based on Sanders shell theory, Galerkin method was utilized to discretize the energy equations, external excitation, and nonlinear restraint forces. And the nonlinear governing equations of motion were derived by using Lagrange equation. The displacements in three directions were represented by the characteristic orthogonal polynomial series and trigonometric functions. The effects of supporting stiffness and supported clearance on dynamic behavior of pipe wall were discussed. The results show that the existence of supported clearance may lead to the changing of stiffness of the pipe vibration system and the dynamic behaviors of the pipe system show nonlinearity and become more complex; for example, the amplitude-frequency curve of the foundation frequency showed hard nonlinear phenomenon. The chaos and bifurcation may emerge at some region of the values of stiffness and clearance, which means that the responses of the pressure thin-wall pipe segment would be more complex, including periodic motion, times periodic motion, and quasiperiodic or chaotic motions.
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LUO, ALBERT C. J., and DENNIS O'CONNOR. "MECHANISM OF IMPACTING CHATTER WITH STICK IN A GEAR TRANSMISSION SYSTEM." International Journal of Bifurcation and Chaos 19, no. 06 (June 2009): 2093–105. http://dx.doi.org/10.1142/s0218127409023937.
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In this paper, an investigation on nonlinear dynamical behaviors of a transmission system with a gear pair is conducted. The transmission system is described through an impact model with a possible stick between the two gears. From the theory of discontinuous dynamical systems, the motion mechanism of impacting chatter with stick is investigated. The onset and vanishing conditions of stick motions are developed, and the condition for maintaining the stick motion is achieved as well. The corresponding physics interpretation is given for a better understanding of nonlinear behaviors of gear transmission systems. Furthermore, such an understanding may be very helpful to improve the efficiency of gear transmission systems.
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Sok, Kwang Won, Manmyung Kim, and Jehee Lee. "Simulating biped behaviors from human motion data." ACM Transactions on Graphics 26, no. 3 (July 29, 2007): 107. http://dx.doi.org/10.1145/1276377.1276511.
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Dar, Tzachi, Leo Joskowicz, and Ehud Rivlin. "Understanding mechanical motion: From images to behaviors." Artificial Intelligence 112, no. 1-2 (August 1999): 147–79. http://dx.doi.org/10.1016/s0004-3702(99)00040-5.
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Shi, Xing Min. "A Brief Review on Models of Animal Tracking in Video." Applied Mechanics and Materials 303-306 (February 2013): 1365–68. http://dx.doi.org/10.4028/www.scientific.net/amm.303-306.1365.
Повний текст джерелаАнотація:
The observation on motion and behaviors of the animal is still important in scientific research fields, and various behaviors of animals are tracked and analyzed for many different purposes. The paper concentrates on the technologies employed for animal tracking in video, and reviews the tracking models related to animal motions and behaviors including shape-based model, contour-based model, articulated model, Bag-Of-Feature based model, Markov Model, etc. and gives a brief summary of these models respectively.
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Shen, Yi Ru, and Qi Wei Wang. "Modeling and Simulation of Swarm Behaviors in Shoal of Fish." Applied Mechanics and Materials 303-306 (February 2013): 1329–33. http://dx.doi.org/10.4028/www.scientific.net/amm.303-306.1329.
Повний текст джерелаАнотація:
Based on the swarm behaviors in shoal of fish, this paper analyzes motion behavior of fish school when fish are foraging. This paper has simulated the pattern of motion behaviors for the fish school quantificationally. Using iterative and updating algorithm, it has modeled the 1-D procedure when fish school gradually approach food. These individual fish that constitute shoal of fish have finite perception and obey simple behavior rules. This paper further adopts modified intelligent optimization algorithm to model the process that individual fish interact with each other, changing position and velocity to gradually be close to food for the 2-D case. Experiment result shows the modified model successfully simulates the swarm behavior in shoal of fish when fish are looking for food, with small relative and absolute error.
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Chong, Kai Leong, Jun-Qiang Shi, Guang-Yu Ding, Shan-Shan Ding, Hao-Yuan Lu, Jin-Qiang Zhong, and Ke-Qing Xia. "Vortices as Brownian particles in turbulent flows." Science Advances 6, no. 34 (August 2020): eaaz1110. http://dx.doi.org/10.1126/sciadv.aaz1110.
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Brownian motion of particles in fluid is the most common form of collective behavior in physical and biological systems. Here, we demonstrate through both experiment and numerical simulation that the movement of vortices in a rotating turbulent convective flow resembles that of inertial Brownian particles, i.e., they initially move ballistically and then diffusively after certain critical time. Moreover, the transition from ballistic to diffusive behaviors is direct, as predicted by Langevin, without first going through the hydrodynamic memory regime. The transitional timescale and the diffusivity of the vortices can be collapsed excellently onto a master curve for all explored parameters. In the spatial domain, however, the vortices exhibit organized structures, as if they are performing tethered random motion. Our results imply that the convective vortices have inertia-induced memory such that their short-term movement can be predicted and their motion can be well described in the framework of Brownian motions.
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Salih, Adham, Joseph Gabbay, and Amiram Moshaiov. "Transferability of Multi-Objective Neuro-Fuzzy Motion Controllers: Towards Cautious and Courageous Motion Behaviors in Rugged Terrains." Mathematics 12, no. 7 (March 27, 2024): 992. http://dx.doi.org/10.3390/math12070992.
Повний текст джерелаАнотація:
This study is motivated by the need to develop generic neuro-fuzzy motion controllers for autonomous vehicles that may traverse rugged terrains. Three types of target problems are investigated. These problems differ in terms of the expected motion behavior, including cautious, intermediate, and courageous behaviors. The target problems are defined as evolutionary multi-objective problems aiming to evolve near optimal neuro-fuzzy controllers that can operate in a variety of scenarios. To enhance the evolution, sequential transfer optimization is considered, where each of the source problems is defined and solved as a bi-objective problem. The performed experimental study demonstrates the ability of the proposed search approach to find neuro-fuzzy controllers that produce the required motion behaviors when operating in various environments with different motion difficulties. Moreover, the results of this study substantiate the hypothesis that solutions with performances near the edges of the obtained approximated bi-objective Pareto fronts of the source problems provide better transferability as compared with those that are associated with performances near the center of the obtained fronts.
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Hayashi, Sora, Kenshi Saho, Daiki Isobe, and Masao Masugi. "Pedestrian Detection in Blind Area and Motion Classification Based on Rush-Out Risk Using Micro-Doppler Radar." Sensors 21, no. 10 (May 13, 2021): 3388. http://dx.doi.org/10.3390/s21103388.
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Various remote sensing technologies have been applied in intelligent vehicles and robots for surrounding-environment recognition. However, these technologies experience difficulties in detecting pedestrians in blind areas and their motions, such as rush-out behaviors. To address this issue, we present a radar-based technique for the detection of pedestrians in blind areas and the classification of different risks of rush-out behaviors among detected pedestrians. We verify their ability to detect pedestrian motion in blind areas by conducting experiments in two environments with blind areas formed by outdoor cars and indoor walls. Then, the classification of motions with different risks of rush-out behaviors among pedestrians detected in the blind areas is demonstrated. We use the clustering method to accurately classify several types of behaviors with different rush-out risks in both environments.
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Sugano, Shigeki, Osamu Matsumoto, and Shin-yo Muto. "Study on Model-Based Control of the Cable-Conduit Drive System." Journal of Robotics and Mechatronics 5, no. 1 (February 20, 1993): 53–59. http://dx.doi.org/10.20965/jrm.1993.p0053.
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The cable-conduit system, one of the remote drive system, is advantageous for integrating multiple-degrees of freedom. However, from the perspective of accurate motion control, a difference is caused between the actuator motion and the joint motion because a considerable friction between the cable and the conduit which varies according to the change in cable route. Therefore, the behaviors of cable must be clarified in order to realize highly accurate motion control. The objective of this study is to clarify the relationship between the actuator motion and the joint motion and to establish the motion control technique of the cable-conduit system. The present paper discusses the model-based control of the cable system. First, we modelled the cable-conduit system using the bend angles and the number of roots and crests of cable. Next, for precisely expressing the behaviors during start-up, we formulated the relationship between the actuator torque and the joint motion in consideration of the static friction and the kinetic friction. In addition, we verified the effectiveness of this formula through an experiment. As a result of the verification experiment, the motion computed from the formula strictly coincided with the actual behavior, thus displaying the effectiveness of the model.
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Rojas, J., and R. A. Peters II. "Sensory Integration with Articulated Motion on a Humanoid Robot." Applied Bionics and Biomechanics 2, no. 3-4 (2005): 171–78. http://dx.doi.org/10.1155/2005/295816.
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This paper describes the integration of articulated motion with auditory and visual sensory information that enables a humanoid robot to achieve certain reflex actions that mimic those of people. Reflexes such as reach-and-grasp behavior enables the robot to learn, through experience, its own state and that of the world. A humanoid robot with binaural audio input, stereo vision, and pneumatic arms and hands exhibited tightly coupled sensory-motor behaviors in four different demonstrations. The complexity of successive demonstrations was increased to show that the reflexive sensory-motor behaviors combine to perform increasingly complex tasks. The humanoid robot executed these tasks effectively and established the groundwork for the further development of hardware and software systems, sensory-motor vector-space representations, and coupling with higher-level cognition.
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Cui, Ning, and Junhong Li. "Dynamic Analysis of a Particle Motion System." Mathematics 7, no. 1 (December 21, 2018): 7. http://dx.doi.org/10.3390/math7010007.
Повний текст джерелаАнотація:
This paper formulates a new particle motion system. The dynamic behaviors of the system are studied including the continuous dependence on initial conditions of the system’s solution, the equilibrium stability, Hopf bifurcation at the equilibrium point, etc. This shows the rich dynamic behaviors of the system, including the supercritical Hopf bifurcations, subcritical Hopf bifurcations, and chaotic attractors. Numerical simulations are carried out to verify theoretical analyses and to exhibit the rich dynamic behaviors.
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Wang, Hongmin, Chi Gao, Hong Fu, Christina Zong-Hao Ma, Quan Wang, Ziyu He, and Maojun Li. "Automated Student Classroom Behaviors’ Perception and Identification Using Motion Sensors." Bioengineering 10, no. 2 (January 18, 2023): 127. http://dx.doi.org/10.3390/bioengineering10020127.
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With the rapid development of artificial intelligence technology, the exploration and application in the field of intelligent education has become a research hotspot of increasing concern. In the actual classroom scenarios, students’ classroom behavior is an important factor that directly affects their learning performance. Specifically, students with poor self-management abilities, particularly specific developmental disorders, may face educational and academic difficulties owing to physical or psychological factors. Therefore, the intelligent perception and identification of school-aged children’s classroom behaviors are extremely valuable and significant. The traditional method for identifying students’ classroom behavior relies on statistical surveys conducted by teachers, which incurs problems such as being time-consuming, labor-intensive, privacy-violating, and an inaccurate manual intervention. To address the above-mentioned issues, we constructed a motion sensor-based intelligent system to realize the perception and identification of classroom behavior in the current study. For the acquired sensor signal, we proposed a Voting-Based Dynamic Time Warping algorithm (VB-DTW) in which a voting mechanism is used to compare the similarities between adjacent clips and extract valid action segments. Subsequent experiments have verified that effective signal segments can help improve the accuracy of behavior identification. Furthermore, upon combining with the classroom motion data acquisition system, through the powerful feature extraction ability of the deep learning algorithms, the effectiveness and feasibility are verified from the perspectives of the dimensional signal characteristics and time series separately so as to realize the accurate, non-invasive and intelligent children’s behavior detection. To verify the feasibility of the proposed method, a self-constructed dataset (SCB-13) was collected. Thirteen participants were invited to perform 14 common class behaviors, wearing motion sensors whose data were recorded by a program. In SCB-13, the proposed method achieved 100% identification accuracy. Based on the proposed algorithms, it is possible to provide immediate feedback on students’ classroom performance and help them improve their learning performance while providing an essential reference basis and data support for constructing an intelligent digital education platform.
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XUEJUN, GAO. "BIFURCATION BEHAVIORS OF THE TWO-STATE VARIABLE FRICTION LAW OF A ROCK MASS SYSTEM." International Journal of Bifurcation and Chaos 23, no. 11 (November 2013): 1350184. http://dx.doi.org/10.1142/s0218127413501848.
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Based on the stability and bifurcation theory of dynamical systems, the bifurcation behaviors and chaotic motions of the two-state variable friction law of a rock mass system are investigated by the bifurcation diagrams based on the continuation method and the Poincaré maps. The stick-slip of the rock mass is formulated as an initial values problem for an autonomous system of three coupled nonlinear ordinary differential equations (ODEs) of first order. The results of linear stability analysis indicate that there is an equilibrium position in the rock mass system. Furthermore, numerical results of nonlinear analysis indicate that the equilibrium position loses its stability from a sup-critical Hopf bifurcation point, and then the bifurcating periodic motion evolves into chaotic motion through a series of period-doubling bifurcations with the decreasing of the control parameter. The stick-slip and chaotic motions evolve into infinity in the end with some unstable periodic motions.
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Huang, Jiahua, Shuo Liang, Caicong Wu, Zhihong Kou, and Ying Chen. "Evaluation System for Agricultural Machinery Operation Based on Smartphone Sensors." Applied Engineering in Agriculture 38, no. 2 (2022): 227–42. http://dx.doi.org/10.13031/aea.14500.
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HighlightsAn evaluation system for agricultural machinery operation was developed.Quantitatively evaluating agricultural machinery operators can support the precision management for agricultural machinery service organizations.The evaluation system can detect and quantify subtle and transient operating behaviors based on smartphone sensors.The evaluation system can distinguish the relative pros and cons of the operating skills of agricultural machinery operators.Abstract. To support the precision management of agricultural machinery operators, scaled agricultural machinery service organizations require comprehensive evaluations for the operating behaviors of each operator, particularly subtle and transient operating behaviors (e.g., sudden acceleration and unstable operating velocities), which greatly influence the operation quality. In this paper, embedded smartphone sensors were utilized to collect high-frequency motion information for agricultural machinery operation, and then, an Agricultural Machinery Operation Evaluation System (AMOES) was designed to evaluate the operating behaviors of the corresponding operators. In AMOES, four evaluation items (the ratio of useful work, the effect on machinery health, the quality of working operation, and the efficiency of U-turn) were defined specifically for the evaluation of subtle and transient operating behaviors, and they were quantified using motion information. Moreover, a case of a scaled agricultural machinery cooperative in Beijing was performed, and AMOES was used to evaluate the operating behaviors of six operators (two autonomous-driving and four manual-driving operators). The case study indicated that the motion data collected by smartphone sensors could capture subtle and transient operating behaviors and that AMOES could effectively detect and quantify subtle operating behaviors. Keywords: Agricultural machinery, Operating behavior, Operation evaluation, Smartphone sensors.
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Li, Jin Hai, Qing Li Yan, and Jin Shuan Liu. "Chaos Behavior and Control of Stay-Cables." Advanced Materials Research 446-449 (January 2012): 1109–14. http://dx.doi.org/10.4028/www.scientific.net/amr.446-449.1109.
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Stay-cable is infinite dimensional nonlinear dynamical system with a very complex vibration types and mechanism which are not described reasonably yet. In order to better control its dynamic behavior, it is necessary to study complex dynamic behavior carefully. Fistly, partial differential equation of the cable motion is established based on the parabolic initial configuration and is simplified into n Duffing-equations by using Galerkin method. Secondly, the chaos behaviors of the first order Duffing-equation under periodic excitation are studied by taking advantage of Melnikov method. At last , parameters may lead to chaotic motion of a true cable in laboratory are calculated and the methods of chaos control are discussed briefly. The study shows that: 1. First order vibration of cable under periodic excitation has much more complex behaviors than the freedom vibration; 2. The Melnikov method can be very effective and convenient for the analysis of chaotic motion of cable.
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Zhang, Ying, Xiaole Yue, Lin Du, Liang Wang, and Tong Fang. "Generation and Evolution of Chaos in Double-Well Duffing Oscillator under Parametrical Excitation." Shock and Vibration 2016 (2016): 1–8. http://dx.doi.org/10.1155/2016/6109062.
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The generation and evolution of chaotic motion in double-well Duffing oscillator under harmonic parametrical excitation are investigated. Firstly, the complex dynamical behaviors are studied by applying multibifurcation diagram and Poincaré sections. Secondly, by means of Melnikov’s approach, the threshold value of parameterμfor generation of chaotic behavior in Smale horseshoe sense is calculated. By the numerical simulation, it is obvious that asμexceeds this threshold value, the behavior of Duffing oscillator is still steady-state periodic but the transient motion is chaotic; until the top Lyapunov exponent turns to positive, the motion of system turns to permanent chaos. Therefore, in order to gain an insight into the evolution of chaotic behavior afterμpassing the threshold value, the transient motion, basin of attraction, and basin boundary are also investigated.
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Kasai, Ryuji, Takashi Goso, and Tetsuro Osawa. "Development of a program for automatic identification of productivity of construction workers." IOP Conference Series: Earth and Environmental Science 1195, no. 1 (June 1, 2023): 012042. http://dx.doi.org/10.1088/1755-1315/1195/1/012042.
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Abstract In the Japanese construction industry, work environment and productivity data of construction projects are collected and analyzed by on-site engineers as individual data based on attendance and performance records. Therefore, productivity data are not uniformly collected and cannot be considered as highly reliable. Therefore, in this study, a prototype of a system is developed that automatically collects data regarding the workers’ activities using sensors and analyzes the working environment and productivity of construction projects. Although image analysis is typically employed for capturing workers’ activities, it is extremely costly and time-consuming for collecting and discriminating data. In addition, it is not practical because it requires adjusting the system to suit the changing environment of the construction site each time. Accordingly, we have conducted motion-detection using accelerometers, gyro-sensors, and GPS that can be attached to individual workers. We have constructed a hierarchical system that combines a phase to detect large acceleration changes that trigger motion, a phase to discriminate periodic motion, and a phase to classify motion by machine learning. The system classified motions into three productivity types: “direct work,” “support,” and “delay.” As a result of applying this system to the sensing data of workers performing road pavement construction-related works, the system discriminated with an overall accuracy rate of 42%. Furthermore, because of the wide range of behaviors that correspond to each productivity behavior category, a large amount of data must be read from the site adopting the system for obtaining training data to perform final behavior classification by machine learning based on the sensing data. Therefore, a system relying on machine learning may not be able to achieve a higher accuracy; thus, in the near future, we aim to automatically discriminate the nine categories of productivity behaviors shown in previous studies.
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Coombs, Sheryl, Joe Bak-Coleman, and John Montgomery. "Rheotaxis revisited: a multi-behavioral and multisensory perspective on how fish orient to flow." Journal of Experimental Biology 223, no. 23 (December 1, 2020): jeb223008. http://dx.doi.org/10.1242/jeb.223008.
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ABSTRACTHere, we review fish rheotaxis (orientation to flow) with the goal of placing it within a larger behavioral and multisensory context. Rheotaxis is a flexible behavior that is used by fish in a variety of circumstances: to search for upstream sources of current-borne odors, to intercept invertebrate drift and, in general, to conserve energy while preventing downstream displacement. Sensory information available for rheotaxis includes water-motion cues to the lateral line and body-motion cues to visual, vestibular or tactile senses when fish are swept downstream. Although rheotaxis can be mediated by a single sense, each sense has its own limitations. For example, lateral line cues are limited by the spatial characteristics of flow, visual cues by water visibility, and vestibular and other body-motion cues by the ability of fish to withstand downstream displacement. The ability of multiple senses to compensate for any single-sense limitation enables rheotaxis to persist over a wide range of sensory and flow conditions. Here, we propose a mechanism of rheotaxis that can be activated in parallel by one or more senses; a major component of this mechanism is directional selectivity of central neurons to broad patterns of water and/or body motions. A review of central mechanisms for vertebrate orienting behaviors and optomotor reflexes reveals several motorsensory integration sites in the CNS that could be involved in rheotaxis. As such, rheotaxis provides an excellent opportunity for understanding the multisensory control of a simple vertebrate behavior and how a simple motor act is integrated with others to form complex behaviors.
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Min, Fuhong, and Zhi Rui. "Boundary dynamics of a non-smooth memristive Hindmarsh–Rose neuron system." Chaos: An Interdisciplinary Journal of Nonlinear Science 32, no. 10 (October 2022): 103117. http://dx.doi.org/10.1063/5.0107067.
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In this paper, the complex dynamics of non-smooth Hindmarsh–Rose (HR) neuron system with local active memristors is discussed through the theory of discontinuous dynamical system. Six mapping structures through two boundaries are employed to illustrate the various switching behaviors of the system. The analytical conditions of the HR system for the switching motions, such as passable motion and grazing motion, are investigated, and the extreme multistability of the improved HR neuron is revealed through switching bifurcations, parameter maps, and attraction basins. The firing activities of various modes in the HR system and the coexistence of various firing behaviors are observed by changing the initial values. Furthermore, the hardware circuit implement of the HR system is established to validate the numerical results.
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Chen, Yunxiang, and Xiangping Liu. "How Chinese People Expressed Well-Being and Mobility Change During the COVID-19 Pandemic: An Analysis of Microblogs." American Journal of Psychology 136, no. 2 (July 1, 2023): 143–52. http://dx.doi.org/10.5406/19398298.136.2.03.
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Abstract This study used Weibo microblog records to analyze and compare the changes in the well-being and mobility of people in China in 2020 (when the COVID-19 outbreak was announced) and 2021 (when the vaccine was announced). Python software's crawling program was used to randomly select 477 users (45.28% of whom were male) and their 16,645 records from January 2020 to April 2021. The word frequency in each microblog text was conceptually defined as a variable, such as self-reference, emotion, and mobility words. Analysis of Weibo user behavior over a year in 2020 and 4 months in 2021 revealed that self-representation (when talking about “I”) had a lower positive affect and higher negative affect at later times than at earlier times. When users discussed “we,” their group identity displayed lower positive affect and more motion behaviors (e.g., shopping and walking outside). However, in 2021, their group identity had a higher positive affect and more motion behaviors, and their self-representation had a lower positive affect and fewer motion behaviors. The implications, limitations, and potential future research are discussed.
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Perks, J., and R. N. Valani. "Dynamics, interference effects, and multistability in a Lorenz-like system of a classical wave–particle entity in a periodic potential." Chaos: An Interdisciplinary Journal of Nonlinear Science 33, no. 3 (March 2023): 033147. http://dx.doi.org/10.1063/5.0125727.
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A classical wave–particle entity (WPE) can be realized experimentally as a droplet walking on the free surface of a vertically vibrating liquid bath, with the droplet’s horizontal walking motion guided by its self-generated wave field. These self-propelled WPEs have been shown to exhibit analogs of several quantum and optical phenomena. Using an idealized theoretical model that takes the form of a Lorenz-like system, we theoretically and numerically explore the dynamics of such a one-dimensional WPE in a sinusoidal potential. We find steady states of the system that correspond to a stationary WPE as well as a rich array of unsteady motions, such as back-and-forth oscillating walkers, runaway oscillating walkers, and various types of irregular walkers. In the parameter space formed by the dimensionless parameters of the applied sinusoidal potential, we observe patterns of alternating unsteady behaviors suggesting interference effects. Additionally, in certain regions of the parameter space, we also identify multistability in the particle’s long-term behavior that depends on the initial conditions. We make analogies between the identified behaviors in the WPE system and Bragg’s reflection of light as well as electron motion in crystals.
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Ito, Yoichiro. "Two-phase Motion in Hydrodynamic Counter-current Chromatography." Current Chromatography 7, no. 2 (December 29, 2020): 76–81. http://dx.doi.org/10.2174/2213240606666190912161221.
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Background: Motion of the two mutually immiscible liquids in hydrodynamic countercurrent chromatographic systems is speculated based on the observation of their behavior in a closed coiled tube rotating in unit gravity. Materials and Methods: The experiment revealed an up and down pattern of four stages of twophase volume ratio occupied at the head end of the coil according to the rotation speed. These two-phase behaviors are comprehensively explained on the bases of interplay between the unit gravity and centrifugal force generated by rotation of the coil. This theory is successfully extended to explain the two-phase behavior in a coil undergoing the type-I and type-J planetary motions. Results and Discussion: The type-I planetary motion produces the centrifugal force distribution similar to that of slowly rotating coil in unit gravity (Stage I), where both phases competitively move toward the head of the coil. In contrast, the type-J planetary motion displays complex distribution patterns of centrifugal force according to the location of the coil on the holder hence the two-phase motion varies with the ß values. When ß is 0.5 – 0.75, the force pattern simulates that of the rotating coil in unit gravity at 120 rpm (Stage III) where the lighter phase moves toward the head leaving the heavier phase behind. Conclusion: This clearly demonstrates the importance of the proper choice of ß values in highspeed countercurrent chromatography utilizing the type-J planetary motion.
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Xiulong, Chen, Jia Yonghao, Deng Yu, and Wang Qing. "Dynamics Behavior Analysis of Parallel Mechanism with Joint Clearance and Flexible Links." Shock and Vibration 2018 (2018): 1–17. http://dx.doi.org/10.1155/2018/9430267.
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In this study, the dynamics behaviors analysis of parallel mechanism considering joint clearance and flexible links are investigated using a computational methodology. The nonlinear dynamic model of 4-UPS-RPS spatial parallel mechanism with clearance in spherical joint and flexible links is established by combining KED method and Lagrange method. The dynamic responses including collision force and motion characteristics of the moving platform are obtained. Chaos and bifurcation are analyzed. The effects of different clearances on the dynamics behaviors of the parallel mechanism are studied. The results show that 4-UPS-RPS spatial parallel mechanism is very sensitive to joint clearance and flexible links, and small variations in the clearance value can cause the mechanism change from periodic motion to chaotic motion. This research provides a methodology for forecasting the dynamics behavior of parallel mechanisms with clearance and flexible links.
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Li, Xiangkun, Guoqing Sun, and Yifei Li. "Human Motion Representation and Motion Pattern Recognition Based on Complex Fuzzy Theory." Complexity 2021 (October 14, 2021): 1–12. http://dx.doi.org/10.1155/2021/9923748.
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With the development of science and technology, the introduction of virtual reality technology has pushed the development of human-computer interaction technology to a new height. The combination of virtual reality and human-computer interaction technology has been applied more and more in military simulation, medical rehabilitation, game creation, and other fields. Action is the basis of human behavior. Among them, human behavior and action analysis is an important research direction. In human behavior and action, recognition research based on behavior and action has the characteristics of convenience, intuition, strong interaction, rich expression information, and so on. It has become the first choice of many researchers for human behavior analysis. However, human motion and motion pictures are complex objects with many ambiguous factors, which are difficult to express and process. Traditional motion recognition is usually based on two-dimensional color images, while two-dimensional RGB images are vulnerable to background disturbance, light, environment, and other factors that interfere with human target detection. In recent years, more and more researchers have begun to use fuzzy mathematics theory to identify human behaviors. The plantar pressure data under different motion modes were collected through experiments, and the current gait information was analyzed. The key gait events including toe-off and heel touch were identified by dynamic baseline monitoring. For the error monitoring of key gait events, the screen window is used to filter the repeated recognition events in a certain period of time, which greatly improves the recognition accuracy and provides important gait information for motion pattern recognition. The similarity matching is performed on each template, the correct rate of motion feature extraction is 90.2%, and the correct rate of motion pattern recognition is 96.3%, which verifies the feasibility and effectiveness of human motion recognition based on fuzzy theory. It is hoped to provide processing techniques and application examples for artificial intelligence recognition applications.
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Bi, Dianfang, Tiezhi Sun, Yingjie Wei, and Xudong Huang. "On the dynamic behaviors of freely falling annular disks at different Reynolds numbers." Physics of Fluids 34, no. 4 (April 2022): 043307. http://dx.doi.org/10.1063/5.0084103.
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Freely falling or rising objects in quiescent Newtonian fluid have been frequently encountered in nature or industry, such as the spreading of seeds from a tree or the movement of ores in deep sea mining. The dynamic behaviors of freely moving objects can provide a significant understanding of the evolution of the body wake and the resulting path instability. In this study, we present numerical simulations of freely falling annular disks released from quiescent water for relatively low Reynolds numbers from 10 to 500 while keeping the non-dimensional moment of inertia [Formula: see text] and inner to outer diameter ratio η constant. The falling stage experiences a variation from quasi-one-dimensional mode, steady oblique motion (SO motion), to the fully three-dimensional mode, helical motion. The stage diagram is plotted to show the variation tendency with the increment of Reynolds numbers. The detailed characteristics of the trajectories and orientation of the annular disks for different motions are analyzed. The corresponding vortical structures are presented, and an analog of the wingtip vortex is found at the outer rim of the disk for transitional and helical motion. A steady recirculation region of SO motion is observed, which is similar to that of a stationary disk but with complex multilayer structures formed by the combined effects of both the inner and outer rims. The limit streamline and pressure coefficient are investigated, demonstrating that the asymmetrical pressure distribution that exerts fluid forces and torques on the disk plays a crucial role in the dynamic response of the disk. Furthermore, combining the flow fields and fluid forces, the physical mechanism responsible for the diverse falling patterns is explored in detail.
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Fan, Jinjun, Ping Liu, Tianyi Liu, Shan Xue, and Zhaoxia Yang. "Analysis of Discontinuous Dynamical Behaviors of a Friction-Induced Oscillator with an Elliptic Control Law." Mathematical Problems in Engineering 2018 (2018): 1–33. http://dx.doi.org/10.1155/2018/5301747.
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This paper develops the passability conditions of flow to the discontinuous boundary and the sticking or sliding and grazing conditions to the separation boundary in the discontinuous dynamical system of a friction-induced oscillator with an elliptic control law and the friction force acting on the mass M through the analysis of the corresponding vector fields and G-functions. The periodic motions of such a discontinuous system are predicted analytically through the mapping structure. Finally, the numerical simulations are given to illustrate the analytical results of motion for a better understanding of physics of motion in the mass-spring-damper oscillator.
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Shi, Zhengrui, Lujie Cao, Yu Han, Haixing Liu, Fengshou Jiang, and Yu Ren. "Research on Recognition of Motion Behaviors of Copepods." IEEE Access 8 (2020): 141224–33. http://dx.doi.org/10.1109/access.2020.3012873.
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Morio, Yoshinari, Tomoko Shoji, and Katsusuke Murakami. "Working motion templates for detecting agricultural worker behaviors." Engineering in Agriculture, Environment and Food 9, no. 4 (October 2016): 297–304. http://dx.doi.org/10.1016/j.eaef.2016.03.002.
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Xie, Shiyang, and Yepeng Guan. "Motion instability based unsupervised online abnormal behaviors detection." Multimedia Tools and Applications 75, no. 12 (June 3, 2015): 7423–44. http://dx.doi.org/10.1007/s11042-015-2664-8.
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