On Schr\"odinger equations involving the regional fractional Laplacian in a ball with the zero boundary condition

Our purpose in this article to show the existence of positive classical solutions of $$( - \Delta )_{B_1}^s u +u=h_1 u^p+\epsilon h_2 \quad {\rm in} \ \, B_1,\qquad u = 0 \quad {\rm on}\ \partial B_1$$ for $\epsilon>0$ small enough, where $( - \Delta )_{B_1}^s$ is the regional fractional Laplacian, $p>1$, $h_i$ with $i=1,2$ are H\"older continuous and satisfy some additional conditions. Our existence is based on the solution of $$( - \Delta )_{B_1}^s u +u=1 \quad {\rm in} \ \, B_1,\qquad u = 0 \quad {\rm on}\ \partial B_1.$$Comment: 2

Numerical Modelling of a Novel Joint System for Grid Shells with T Cross-sections

A novel joint system developed for single-layered steel grid shells with T cross-sections is presented in this paper. The joint system is bolted to facilitate quick and easy on-site assembly. First, a solid finite element model was built to investigate the behaviour of the developed joint system. The moment-rotation characteristics of the joint system were determined and the joint strength and stiffness was investigated. Key parameters influencing the behaviour of the joint were studied, such as bolt diameter, pretension, component geometry and normal force. As a second step, free-form roof structures with a span of 40÷80 meters were chosen and analysed with the developed joints. The previously obtained moment-rotation results were used as spring moment-rotation characteristics in beam finite element models. The load bearing capacity of the structures were determined. The results were compared to that of grid shells with rigid joints, and it was shown that the joint system is stiff enough

A Manipulator-Assisted Multiple UAV Landing System for USV Subject to Disturbance

Marine waves significantly disturb the unmanned surface vehicle (USV) motion. An unmanned aerial vehicle (UAV) can hardly land on a USV that undergoes irregular motion. An oversized landing platform is usually necessary to guarantee the landing safety, which limits the number of UAVs that can be carried. We propose a landing system assisted by tether and robot manipulation. The system can land multiple UAVs without increasing the USV's size. An MPC controller stabilizes the end-effector and tracks the UAVs, and an adaptive estimator addresses the disturbance caused by the base motion. The working strategy of the system is designed to plan the motion of each device. We have validated the manipulator controller through simulations and well-controlled indoor experiments. During the field tests, the proposed system caught and placed the UAVs when the disturbed USV roll range was approximately 12 degrees

Design and Control of the "TransBoat": A Transformable Unmanned Surface Vehicle for Overwater Construction

This paper presents the TransBoat, a novel omnidirectional unmanned surface vehicle (USV) with a magnetbased docking system for overwater construction with wave disturbances. This is the first such USV that can build overwater structures by transporting modules. The TransBoat incorporates two features designed to reject wave disturbances. First, the TransBoat's expandable body structure can actively transform from a mono-hull into a multi-hull for stabilization in turbulent environments by extending its four outrigger hulls. Second, a real-time nonlinear model predictive control (NMPC) scheme is proposed for all shapes of the TransBoat to enhance its maneuverability and resist disturbance to its movement, based on a nonlinear dynamic model. An experimental approach is proposed to identify the parameters of the dynamic model, and a subsequent trajectory tracking test validates the dynamics, NMPC controller and system mobility. Further, docking experiments identify improved performance in the expanded form of the TransBoat compared with the contracted form, including an increased success rate (of ~ 10%) and reduced docking time (of ~ 40 s on average). Finally, a bridge construction test verifies our system design and the NMPC control method

A Novel Autonomous Robotics System for Aquaculture Environment Monitoring

Implementing fully automatic unmanned surface vehicles (USVs) monitoring water quality is challenging since effectively collecting environmental data while keeping the platform stable and environmental-friendly is hard to approach. To address this problem, we construct a USV that can automatically navigate an efficient path to sample water quality parameters in order to monitor the aquatic environment. The detection device needs to be stable enough to resist a hostile environment or climates while enormous volumes will disturb the aquaculture environment. Meanwhile, planning an efficient path for information collecting needs to deal with the contradiction between the restriction of energy and the amount of information in the coverage region. To tackle with mentioned challenges, we provide a USV platform that can perfectly balance mobility, stability, and portability attributed to its special round-shape structure and redundancy motion design. For informative planning, we combined the TSP and CPP algorithms to construct an optimistic plan for collecting more data within a certain range and limiting energy restrictions.We designed a fish existence prediction scenario to verify the novel system in both simulation experiments and field experiments. The novel aquaculture environment monitoring system significantly reduces the burden of manual operation in the fishery inspection field. Additionally, the simplicity of the sensor setup and the minimal cost of the platform enables its other possible applications in aquatic exploration and commercial utilization

Support Vector Machine for Behavior-Based Driver Identification System

We present an intelligent driver identification system to handle vehicle theft based on modeling dynamic human behaviors. We propose to recognize illegitimate drivers through their driving behaviors. Since human driving behaviors belong to a dynamic biometrical feature which is complex and difficult to imitate compared with static features such as passwords and fingerprints, we find that this novel idea of utilizing human dynamic features for enhanced security application is more effective. In this paper, we first describe our experimental platform for collecting and modeling human driving behaviors. Then we compare fast Fourier transform (FFT), principal component analysis (PCA), and independent component analysis (ICA) for data preprocessing. Using machine learning method of support vector machine (SVM), we derive the individual driving behavior model and we then demonstrate the procedure for recognizing different drivers by analyzing the corresponding models. The experimental results of learning algorithms and evaluation are described