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In this study, the hydrodynamic performance of a dish-shaped autonomous underwater helicopter (AUH) in waves near the sea surface is examined. The AUH is a novel type of autonomous underwater vehicle (AUV) that has excellent maneuverability and flexibility. The hydrodynamic performance of a dish-shaped autonomous underwater helicopter (AUH) in waves near the sea surface is estimated. An AUH is a novel...
Underwater obstacle detection is essential for safe deployment of autonomous underwater vehicles (AUVs). In this paper, we make an attempt to explore one kind of underwater obstacle detection strategy with the help of the Relative Total Variation(RTV) and Joint Guided Filtering(JGF). We first introduce one kind of virtual retinex model. Then we utilize the Relative Total Variation to extract the essential...
This paper presents the motion simulation of an autonomous underwater helicopter (AUH), a new type of underwater vehicle proposed by Zhejiang University. In order to determine whether its controllability meets the design requirements, a singularity-free unit quaternion stable control method is used for simulating the AUH performance in MATLAB, including its force and trajectory under different types...
The underwater vehicles are always being disturbed by ocean current when they work under the sea. In this paper, the Magnus force of a new type autonomous underwater vehicle (AUV) named “autonomous underwater helicopter (AUH)”, a disk-shaped deep-sea underwater vehicle, was analyzed to help it move away from a deep-sea region with temporary ocean current. The simulation technique of the ANSYS-CFX...
In order to study the influence of vertical grounding electrode on impulse grounding resistance of substation ground network, the grounding model was built in COMSOL, and the impulse grounding resistances of substation grounding grid in different distribution, length and quantity of vertical grounding electrode were simulated and calculated. The results show that the closer the vertical ground to...
Wearable and mobile medical devices provide efficient, comfortable, and economic health monitoring, having a wide range of applications from daily to clinical scenarios. Health data security becomes a critically important issue. Electrocardiogram (ECG) has proven to be a potential biometric in human recognition over the past decade. Unlike conventional authentication methods using passwords, fingerprints,...
In this paper, an efficient content-based rate control scheme is proposed in the context of rate-distortion optimization for 3-D wavelet-based scalable video coding (SVC). Despite the prevalence of the conventional rate control methods in DCT-based SVC, the underlying formulation is not directly applicable to 3-D wavelet-based SVC. Performing optimal rate control with 3-D wavelet coding methods is...
Energy and carbon issue have gained a lot of attention in recent years. However, energy management and services of electric bicycles based on international standards are not very common. This work uses communication standards, including Energybus, MQTT and Bluetooth 4.0 to design an energy management service platform. We implement a system that integrates electric bicycles, smart mobile devices and...
This paper proposes a novel passive hybrid high-voltage DC circuit breaker based on thyristors. A current commutation circuit to turn off the thyristors is designed with elements of relatively low current and voltage ratings. Moreover, voltage balancing strategy is applied to protect the series-connected device.
Volterra series have been popular in non-linear system analysis and modeling for a long time. Volterra representation adapts the convolution concept from linear time-invariant (LTI) systems, generalizes it to “super convolutions” and, hence, are able to characterize the dynamical behavior of non-linear circuits using familiar LTI techniques. It is extensively used in white-box verification problems...
Atomization parameters of liquid droplets in the spray cooling system-droplets velocity, droplets diameter, droplets distribution and others influence significantly on the heat exchange efficiency. This paper uses Phase Doppler Particle Analyser(PDPA) to make a precise measurement on atomization parameters on the spray cooling system used pressure atomizing spray nozzle. Then described the distribution...
Monocular visual odometry as the front end of SLAM, its task is to estimate the movement of cameras between adjacent images. One of the most important steps in visual odometry is to find feature correspondence between neighboring frames. In finding the feature matches, the search region can not be too small in order to ensure a large number of matches to be found. On the other hand, it could not be...
This paper presents an interesting feature of the resonant slotted-waveguide antenna array: the difference pattern at off-center frequencies. Our demonstration uses a 12-element center-fed resonant slot array on rectangular waveguide. The simulation results show that the array produces a sum beam pattern at center frequency, and difference beam patterns at two off-center frequencies (around ±8%)....
It is believed that renewable energy can help to ease the shortage of fossil fuels, and to protect environment. Moreover, microgrid provides a practical way for renewable energy and electric vehicles to access the grid easily. In this paper, a PV hybrid DC/AC microgrid which based on the DC microgrid is proposed. It combines the advantages of simple control of DC microgrids and the novel uninterruptible...
Antennas for microwave heating radiate high levels of power relative to communications and most radar applications. The problem of voltage breakdown becomes a dominant factor in the antenna design. The breakdown problem is compounded when the heating is in a partial vacuum, which can be worse than the full vacuum situation of space-borne antennas. Resonant slot array antennas are ideal for microwave...
As Cyber-Physical Systems (CPS) operate in open, dynamic and diverse environments, they need to be self-adaptive to address the uncertainty challenges. And it is urgent to study self-adaptive software intensive Cyber-Physical Systems (self-adaptive CPS). As self-adaptive CPS interact closely with the environments and users, their requirements analysis is particularly challenging. General requirement...
This paper describes a marine power station (MPS) control system with centralized management and decentralized monitoring based on Active Disturbance Rejection Control (ADRC). By combining S7-1200 PLC and human machine interface (HMI), the control system sends data from the generator sets of the MPS to the upper computer (WinCC) in real time through Industrial Ethernet. This new MPS control system...
A compact open-loop antenna with magnetic field enhancement is proposed for near-field operations in the ultra-high frequency (UHF) band, which is able to generate a strong and uniform magnetic field in a near-field zone of the open-loop. The open-loop with half-wavelength perimeters is etched on single-layer of FR4 printed circuit board. The fabricated compact antenna with an overall size of a dimension...
A new, simple, probe-fed technique for a ridged waveguide slot array is presented. The application is for satellite synthetic aperture radar (SAR). The array is fed in the center by a coaxial probe whose inner conductor is attached to the ceiling of the ridged waveguide. An example design of a 6-element slot array with the probe is evaluated by simulation. The −10 dB return loss is around 4% and the...
Virtual laboratory helps students' learning of experiment manipulation and scientific concepts before they actually enter the real chemistry laboratory. It also helps reduce the risks in conducting the real chemistry experiments and reduce the cost for chemistry experiment materials. This study developed an educational game "O2 LAB©", on the mobile...
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