Recurrent 3D Pose Sequence Machines

3D human articulated pose recovery from monocular image sequences is very challenging due to the diverse appearances, viewpoints, occlusions, and also the human 3D pose is inherently ambiguous from the monocular imagery. It is thus critical to exploit rich spatial and temporal long-range dependencies among body joints for accurate 3D pose sequence prediction. Existing approaches usually manually design some elaborate prior terms and human body kinematic constraints for capturing structures, which are often insufficient to exploit all intrinsic structures and not scalable for all scenarios. In contrast, this paper presents a Recurrent 3D Pose Sequence Machine(RPSM) to automatically learn the image-dependent structural constraint and sequence-dependent temporal context by using a multi-stage sequential refinement. At each stage, our RPSM is composed of three modules to predict the 3D pose sequences based on the previously learned 2D pose representations and 3D poses: (i) a 2D pose module extracting the image-dependent pose representations, (ii) a 3D pose recurrent module regressing 3D poses and (iii) a feature adaption module serving as a bridge between module (i) and (ii) to enable the representation transformation from 2D to 3D domain. These three modules are then assembled into a sequential prediction framework to refine the predicted poses with multiple recurrent stages. Extensive evaluations on the Human3.6M dataset and HumanEva-I dataset show that our RPSM outperforms all state-of-the-art approaches for 3D pose estimation.Comment: Published in CVPR 201

Random-Singlet Phase in Disordered Two-Dimensional Quantum Magnets

We study effects of disorder (randomness) in a 2D square-lattice $S=1/2$ quantum spin system, the $J$-$Q$ model with a 6-spin interaction $Q$ supplementing the Heisenberg exchange $J$. In the absence of disorder the system hosts antiferromagnetic (AFM) and columnar valence-bond-solid (VBS) ground states. The VBS breaks $Z_4$ symmetry, and in the presence of arbitrarily weak disorder it forms domains. Using QMC simulations, we demonstrate two kinds of such disordered VBS states. Upon dilution, a removed site leaves a localized spin in the opposite sublattice. These spins form AFM order. For random interactions, we find a different state, with no order but algebraically decaying mean correlations. We identify localized spinons at the nexus of domain walls between different VBS patterns. These spinons form correlated groups with the same number of spinons and antispinons. Within such a group, there is a strong tendency to singlet formation, because of spinon-spinon interactions mediated by the domain walls. Thus, no long-range AFM order forms. We propose that this state is a 2D analog of the well-known 1D random singlet (RS) state, though the dynamic exponent $z$ in 2D is finite. By studying the T-dependent magnetic susceptibility, we find that $z$ varies, from $z=2$ at the AFM--RS phase boundary and larger in the RS phase The RS state discovered here in a system without geometric frustration should correspond to the same fixed point as the RS state recently proposed for frustrated systems, and the ability to study it without Monte Carlo sign problems opens up opportunities for further detailed characterization of its static and dynamic properties. We also discuss experimental evidence of the RS phase in the quasi-two-dimensional square-lattice random-exchange quantum magnets Sr$_2$CuTe$_{1-x}$W$_x$O$_6$.Comment: 31 pages, 29 figures; substantial additions in v2; additional analysis in v

Investigating the Knowledge-Sharing Behavior ina Professional Virtual Community

This research aims at investigating the knowledge sharing-behaviors in a teachers’ professional virtual community. Logs data in the entire community and in special interest groups (SIGs) were analyzed. Some typical behaviors were identified by the clustering analysis in this study. The largest group of member belongs to inactive users. They rarely log in the system, are passive in uploading or downloading teaching materials, and almost never post or reply messages. Another group is active in receiving knowledge while reluctant to give knowledge or to respond. The third group frequently login the system, is the most active in sharing knowledge, and actively searching knowledge. However, the third group contains only a small number of members. Furthermore, fifty-five members of the knowledge-sharing group were interviewed using focus group technique to find out qualitative information as to why they are willing to share information and what are their concerns in sharing information. The results indicated that knowledge sharing is not a common behavior in professional virtual community, and knowledge-sharing culture is difficult to promote even in non-competitive professional communities. Secondly, knowledge cannot flow easily throughout the community even when certain knowledge flow promoting mechanism is provided. Thirdly, professional autonomy may hinder the frequency of interactions with others in professional virtual community. Fourthly, attitudes regarding information ownership are important factors in knowledge sharing of a professional virtual community. Finally, teaching and IT usage experiences are not major factors affecting knowledge-sharing behavior in pro fessional virtual communities

Random-singlet phase in disordered two-dimensional quantum magnets

We study effects of disorder (randomness) in a 2D square-lattice S=1/2 quantum spin system, the J-Q model with a 6-spin interaction Q supplementing the Heisenberg exchange J. In the absence of disorder the system hosts antiferromagnetic (AFM) and columnar valence-bond-solid (VBS) ground states. The VBS breaks Z4 symmetry, and in the presence of arbitrarily weak disorder it forms domains. Using QMC simulations, we demonstrate two kinds of such disordered VBS states. Upon dilution, a removed site leaves a localized spin in the opposite sublattice. These spins form AFM order. For random interactions, we find a different state, with no order but algebraically decaying mean correlations. We identify localized spinons at the nexus of domain walls between different VBS patterns. These spinons form correlated groups with the same number of spinons and antispinons. Within such a group, there is a strong tendency to singlet formation, because of spinon-spinon interactions mediated by the domain walls. Thus, no long-range AFM order forms. We propose that this state is a 2D analog of the well-known 1D random singlet (RS) state, though the dynamic exponent z in 2D is finite. By studying the T-dependent magnetic susceptibility, we find that z varies, from z=2 at the AFM--RS phase boundary and larger in the RS phase The RS state discovered here in a system without geometric frustration should correspond to the same fixed point as the RS state recently proposed for frustrated systems, and the ability to study it without Monte Carlo sign problems opens up opportunities for further detailed characterization of its static and dynamic properties. We also discuss experimental evidence of the RS phase in the quasi-two-dimensional square-lattice random-exchange quantum magnets Sr2CuTe1−xWxO6.Accepted manuscrip

Research on Safety and Security Distance of Flammable Liquid Storage Tank

AbstractFlammable liquid storage tanks usually plant a potential dangerous zone. The damage gets worse and worse. In order to avoid the tank fire, the tanks extended to the nearby storage tanks-facilities and buildings. In consideration of safety conditions, flammable liquid storage tanks for the safety and security distance is necessary. Through the FDS (Fire Dynamics Simulator) computer simulation of fire, flammable liquid storage tanks for spot the fires numerical simulation to detect a fire to happen. In order to establish an optimized model, the flammable liquid storage tanks save the temperature distribution by obtaining flammable safety distance of the liquid storage tank, by talking about the current laws and regulations, by looking forward to meeting the economic and security considerations

BIOMECHANICS ANALYSIS OF WATER POLO THROWING

The purpose of this study is to investigate the parameters of displacement. velocity, and acceleration of water polo over arm throwing. Six water polo athletes participated in this study. Kwon 3D was utilized to analyze arm movement of water polo shooting, including the displacement, velocity, and acceleration of wrist, elbow, shoulder, and ball. The results indicated, first, the displacement of arm movement was quadratic polynomial at a frequency of 0.6 second with maximum distance of 130.97 cm for ball, 117.17 cm for wrist, 107.04 cm for elbow, and 94.22 cm for shoulder. Second, the velocity of arm movement was a cubic curve with maximum speed of 25.368 m/s for ball, 20.092 m/s for wrist, 19.732 rn/s for elbow, and 23.846 m/s for shoulder. Moreover, the change of maximum velocity of ball and wrist occurred after 1.5 seconds, while the velocity of elbow and shoulder both decreased for 0.5 seconds. Third, the acceleration of arm movement showed a 6th order polynomial at a frequency of 0.2 second with maximum acceleration of 505.082 m/s2 for ball, 545.526 m/s2 for wrist, 401.82 m/s2 for elbow, and 568.26 m/s2 for shoulder

Comparative study of five commonly used gravity type fish cages under pure current conditions

Gravity type fish cages have been commonly used in marine aquaculture for years. However, only limited research efforts have been made to assess the influences of different design parameters on the structural responses of gravity type fish cages. The present study first develops and validates an open-source numerical library under the toolbox Code_Aster for the structural analyses of fish cages. Then, the newly developed library is employed to conduct time-domain simulations to investigate the effects of the main design parameters on the cultivation volumes and drag forces. In this paper, five circumferences of the floating collar, five depths of the net bag, five weights and nine current velocities are considered in the parametric study of five commonly used fish cages. Moreover, regression functions are proposed based on the large number of numerical results to provide accurate predictions for the most concerning aspects in the design process for fish cages. Based on the parametric study, recommendations for selecting fish cage types and practical guides for cage construction are given. This study should be of value to structural designers as well as researchers wishing to optimise cage design.publishedVersio