The colonization of active sand dunes by rhizomatous plants through vegetative propagation and its role in vegetation restoration

Author's manuscript made available in accordance with the publisher's policy.This study aims to elucidate vegetative propagation in Phragmites communis, and its role in colonizing active sand dunes. The experiment was conducted in the Horqin Sand Land in Inner Mongolia, northeastern China. Quadrats were established along twenty transects from the dune slack to the windward slope through the ecotone (a transitional zone between the dune slack and the windward slope of active sand dune). Biomass, biomass allocation and relative growth rate (RGR) of P. communis were quantified monthly from May to August in 2007. Our results showed that rhizomes extended towards the active sand dune at a rate of 523.5 ± 20.8 cm per year. The RGR of ramets and rhizomes increased along the gradient from the dune slack to the windward slope. The percentage of rhizome biomass in total biomass increased significantly along the same gradient. The results indicate that P. communis is able to adjust growth strategy according to the environmental conditions. The results also demonstrate that vegetative propagation of rhizomatous grasses significantly contributes to plant encroachment to active sand dunes and plays an important role in the vegetation restoration of dune fields

Weak Hopf Algebras, Smash Products and Applications to Adjoint-Stable Algebras

For a semisimple quasi-triangular Hopf algebra $\left( H,R\right)$ over a field $k$ of characteristic zero, and a strongly separable quantum commutative $H$-module algebra $A$ over which the Drinfeld element of $H$ acts trivially, we show that $A\#H$ is a weak Hopf algebra, and it can be embedded into a weak Hopf algebra $\operatorname{End}A^{\ast}\otimes H$. With these structure, $_{A\#H}\operatorname{Mod}$ is the monoidal category introduced by Cohen and Westreich, and $_{\operatorname{End}A^{\ast}\otimes H}\mathcal{M}$ is tensor equivalent to $_{H}\mathcal{M}$. If $A$ is in the M{\"{u}}ger center of $_{H}{\mathcal{M}}$, then the embedding is a quasi-triangular weak Hopf algebra morphism. This explains the presence of a subgroup inclusion in the characterization of irreducible Yetter-Drinfeld modules for a finite group algebra

Large-scale Continuous Gesture Recognition Using Convolutional Neural Networks

This paper addresses the problem of continuous gesture recognition from sequences of depth maps using convolutional neutral networks (ConvNets). The proposed method first segments individual gestures from a depth sequence based on quantity of movement (QOM). For each segmented gesture, an Improved Depth Motion Map (IDMM), which converts the depth sequence into one image, is constructed and fed to a ConvNet for recognition. The IDMM effectively encodes both spatial and temporal information and allows the fine-tuning with existing ConvNet models for classification without introducing millions of parameters to learn. The proposed method is evaluated on the Large-scale Continuous Gesture Recognition of the ChaLearn Looking at People (LAP) challenge 2016. It achieved the performance of 0.2655 (Mean Jaccard Index) and ranked $3^{rd}$ place in this challenge

Large-scale Isolated Gesture Recognition Using Convolutional Neural Networks

This paper proposes three simple, compact yet effective representations of depth sequences, referred to respectively as Dynamic Depth Images (DDI), Dynamic Depth Normal Images (DDNI) and Dynamic Depth Motion Normal Images (DDMNI). These dynamic images are constructed from a sequence of depth maps using bidirectional rank pooling to effectively capture the spatial-temporal information. Such image-based representations enable us to fine-tune the existing ConvNets models trained on image data for classification of depth sequences, without introducing large parameters to learn. Upon the proposed representations, a convolutional Neural networks (ConvNets) based method is developed for gesture recognition and evaluated on the Large-scale Isolated Gesture Recognition at the ChaLearn Looking at People (LAP) challenge 2016. The method achieved 55.57\% classification accuracy and ranked $2^{nd}$ place in this challenge but was very close to the best performance even though we only used depth data.Comment: arXiv admin note: text overlap with arXiv:1608.0633

Stability of delayed virus infection model with a general incidence rate and adaptive immune response

We present the dynamical behaviors of a virus infection model with general infection rate, immune responses and two intracellular delays which describe the interactions of the HIV virus, target cells, CTL cells and antibodies within host. Three factors are incorporated in this model: (1) the intrinsic growth rate of uninfected cells, (2) a nonlinear incidence rate function considering both virus-tocell infection and cell-to-cell transmission, and (3) a nonlinear productivity and removal function. By the method of Lyapunov functionals and LaSalle’s invariance principle, we show that the global dynamics of the model is determined by the reproductive numbers for viral infection R0, for antibody immune response R1, for CTL immune response R2, for CTL immune competition R3 and for antibody immune competition R4. The numerical simulations are given to illustrate our theoretical results

Hierarchical sliding mode attitude control of a spherical underwater exploring robot

Aiming at the attitude control of the spherical underwater robot, the kinematics and dynamics of the underactuated attitude control adjusting system are analyzed, and its dynamics model is established. By using the differential homeomorphism transformation, the model was divided into two subsystems. Based on the advantages of sliding mode variable structure control, this paper adopts the hierarchical sliding mode variable structure method to design the sliding mode of different variables respectively, and then designs the sliding mode of the whole system. The presented control scheme can solve the coupling problem well. The controller has small overshoot and can well suppress chattering phenomenon. The simulation results show that the designed control law can make the system converge quickly and control the attitude of the underwater spherical robot effectively