The Infona portal uses cookies, i.e. strings of text saved by a browser on the user's device. The portal can access those files and use them to remember the user's data, such as their chosen settings (screen view, interface language, etc.), or their login data. By using the Infona portal the user accepts automatic saving and using this information for portal operation purposes. More information on the subject can be found in the Privacy Policy and Terms of Service. By closing this window the user confirms that they have read the information on cookie usage, and they accept the privacy policy and the way cookies are used by the portal. You can change the cookie settings in your browser.
Increased life expectancies have significantly increased the number of individuals suffering from geriatric neurodegenerative diseases such as Alzheimer’s disease (AD) and Parkinson’s disease (PD). The financial cost for current and future patients with these diseases is overwhelming, resulting in substantial economic and societal costs. Unfortunately, most recent high-profile clinical trials for...
In this paper, the natural supercavitys are studied both experimentally and numerically. A series of supercavitating vehicle water-entry test are carried out at different speeds, where it is found that the minimum pressure in the cavity gradually reduced with the increase of water-entry speed. The cause for the evolution progress of natural supercavitation is difficult to get from the experiment,...
This paper proposed two methods to analyze marine riser, which is Finite Element Method (FEM) and Extended Kalman Filter (EKF) method. Due to environmental disturbances and ship motion, the occurrence of riser's large deflections will bring fatigue problems and propagation cracks, which will lead to environmental disasters. Compare the two methods to derive structural parameters of riser, such as...
FrFT is a new tool which has a dominant advantage to detect LFM-signal. However, under the multipath environment, the LFM signal is distortion on account of the non-correlation superimposition of the multipath component, which results in performance degradation of the detector based on FrFT. In this paper, a combination of time-reversal focusing and Fractional Fourier Transform algorithm is proposed...
Many different sensors have been installed on board vessels, a new framework is urgently needed to form a Common Operational Picture (COP), to assist the on-board operations and onshore analysis. In this paper, based on the Visual Analytics framework, we present a spatiotemporal dimension reduction method based on a real world case of oil combat operation. With our prototype, we show that how dimension...
Through and comprehensive tests are necessary to ensure complete stability and reliability of AUV, due to the high risk and consumption of in field testing, onshore testing technology for AUV is proposed. Rudder load simulator plays an important role in the onshore testing of AUV. In this paper, the design and development of a rudder load simulator was discussed. Rudder load calculation method during...
In order to accurately control the portable AUV, a dynamic modeling method based on computational fluid dynamics (CFD) and a improved Generalized Predictive Control (GPC) method were presented. First, the whole modeling process was described from two aspects: dynamic model derivation and model parameter identification. Second, the validity of the model and modeling method were tested by comparing...
The capability of avoiding static obstacles independently is the premise for air cushion vehicle (ACV) operating safely. In this article, an ACV collision avoidance control based on improved artificial potential field method is designed as auxiliary operating system to ensure safe navigation of ACV. It builds mathematical model of the ACV and searches the data of static obstacles. Besides, the collision...
Nowadays, ocean observatory networks, which gather and provide multidisciplinary, long-term, 3D continuous marine observations at multiple temporal spatial scales, play a more and more important role in ocean investigations. In this paper, we try to develop a portable smart device with online fish detection and tracking strategies by ARM7 microprocessor for ocean observatory networks, combining the...
This paper proposes a spline interpolation method to map 2D Dubins paths into 3D for multiple Autonomous Underwater Vehicles (AUVs) to visit multiple targets. The multitarget assignment and path planning problem is first modeled as a multiple Traveling Salesmen Problem (mTSP) and a three-step algorithm is used to solve the NP-hard integer programming problem with affordable computational complexity...
Hydrothermal vent fluids play very important role in the deep-sea geochemistry cycle, and support the extreme biological communities. But, there are very few sensors can be used for the in situ measurement of the chemical compositions of the emerging vent fluids. The extremely high temperature and pressure will kill most of them. The traditional sampling technology cannot maintain the sample temperate...
Autonomous underwater vehicles (AUVs) are becoming increasingly popular for ocean exploration, military and industrial applications. Motion control of AUV is the key to completing these missions. The classical linear Proportional Integral Derivative (PID) controllers are widely used due to its reliability and simplicity. However, it is difficult to tune the parameters in the classical PID controllers...
Arctic coastal morphology is increasingly affected by changes to the climate. As the season length for shorefast ice decreases and temperatures warm permafrost, coastlines are increasingly susceptible to erosion from storm waves. Such coastal erosion is significant since the majority of the population centers and infrastructure in the Arctic are located near the coasts. Stakeholders and decision makers...
In order to improve the robustness of Adaptive Matched Field Processing(AMFP), a Conditional Probability Constraint Matched Field Processing (MFP-CPC) is proposed. The algorithm derives the posterior probability density of the source locations from Bayesian Criterion, then the main lobe of AMFP is protected and the side lobe is restricted by the posterior probability density, so MFP-CPC not only has...
In this paper, a joint synchronization and Doppler scaling factor estimation algorithm has been proposed for underwater acoustic communications. The training sequence, which consists of two Zadoff-Chu (ZC) sequences being conjugate with each other, is utilized to synchronize and estimate Doppler scaling factor, time delay and carrier frequency offsets (CFOs). ZC sequences are well designed to show...
The islands have plentiful renewable energy resources. Fully use of these renewable energy sources will greatly improve the power supply capacity and quality of the offshore micro grid. Considering the randomness and intermittence of the output of these renewable energy sources, it is a good choice to add energy storage devices into the grid to improve the reliability and stability of the system output...
In order to improve the maneuverability and safety of the air cushion vehicle (ACV), considering the internal uncertainties, external disturbances, chattering in sliding mode control, the second order nonsingular terminal sliding mode (SONTSM) controller with extended state observer (ESO) is designed to achieve the course control of ACV. The course controller includes two parts: second order nonsingular...
An event-driven positioning control algorithm based active disturbance rejection control (ADRC) method is proposed for dynamic positioning (DP) ship under the influence of external disturbances. The time-driven positioning controller is firstly designed using ADRC method. Then, the event-driven condition is introduced by extending the designed positioning controller, moreover, the trigger decision...
Underwater acoustic grid network is promising for providing high data rate and wide coverage service. For the scheduled time division multiple access (TDMA) protocols in the underwater acoustic grid networks, scheduling is an essential part to achieve reliable and energy efficient performance. Scheduling not only completely guarantees the interference free transmission in the network, but also makes...
The Sea-Wing7000 underwater glider, developed by the Shenyang Institute of Automation, CAS, is an instrument platform designed to glide to depths of 7000 meters for the application of deep-sea environment variables observation. Similar in structural layout to the “Sea-Wing” glider[1], to achieve these depths, The “Sea-Wing7000” using composite of carbon fiber / resin as the pressure hull. A “Sea-Wing7000”...
Set the date range to filter the displayed results. You can set a starting date, ending date or both. You can enter the dates manually or choose them from the calendar.