Consent for Use of Clinical Leftover Biosample: A Survey among Chinese Patients and the General Public

Background: Storage of leftover biosamples generates rich biobanks for future studies, saving time and money and limiting physical impact to sample donors. Objective: To investigate the attitudes of Chinese patients and the general public on providing consent for storage and use of leftover biosamples. Design, Setting and Participants: Cross-sectional surveys were conducted among randomly selected patients admitted to a Shanghai city hospital (n = 648) and members of the general public (n = 492) from May 2010 to July 2010. Main Outcome Measures: Face-to-face interviews collected respondents-report of their willingness to donate residual biosample, trust in medical institutions, motivation for donation, concerns of donated sample use, expectations for research results return, and so on. Results: The response rate was 83.0%. Of the respondents, 89.1 % stated that they completely understood or understood most of questions. Willingness to donate residual sample was stated by 64.7%, of which 16.7 % desired the option to withdraw their donations anytime afterwards. Only 42.3 % of respondents stated they ‘‘trust’ ’ or ‘‘strongly trust’ ’ medical institutions, the attitude of trusting or strongly trusting medical institutions were significantly associated with willingness to donate in the general public group.(p,0.05) The overall assent rate for future research without specific consents was als

Formation Control of Multiple Underactuated Surface Vessels with a Disturbance Observer

To maintain the formation of underactuated surface vessels (USVs), this study designs a formation controller based on a virtual structure strategy. The problem of formation control is transformed into the problems of tracking the USV position and the virtual structure point position. Meanwhile, to eliminate the effects of model parameter uncertainties and external environment disturbances on USV tracking control, a compensation control algorithm based on disturbance estimation is proposed. The Lyapunov theorem is introduced to ensure that the trajectory tracking error of the proposed control algorithm eventually converges to any small region, which confirms global stability of the designed tracking error. The simulation results demonstrate that the proposed controller can eliminate the effect of external uncertain interference and maintain the formation of multiple USVs

Self-Organizing Cooperative Pursuit Strategy for Multi-USV with Dynamic Obstacle Ships

A self-organizing cooperation strategy for multiple unmanned surface vessels (USVs) to pursue intelligent evaders in the case of a dynamic obstacle vessel is proposed. Firstly, a self-organizing cooperative hunting strategy is proposed to form an Apollonius circle. According to the escape strategies of evaders under different encirclement states, the pursuers are divided into pursuit group and ambush group. The pursuit group drives the evaders into the ambush area and completes the encirclement together with the ambush group. In order to better deal with the dynamic obstacle ships encountered in the pursuit process in the dynamic ocean environment, the artificial potential field-based collision avoidance method for inter-USV and dynamic collision avoidance strategy for encountering obstacle ships based on International Regulations for Preventing Collisions at Sea (COLREGs) are proposed. The simulation results show that the algorithm can make the pursuers complete the encirclement of the evaders and has good obstacle avoidance performance and flexibility in the environment with dynamic obstacle ships

A MISO-ARX-Based Method for Single-Trial Evoked Potential Extraction

In this paper, we propose a novel method for solving the single-trial evoked potential (EP) estimation problem. In this method, the single-trial EP is considered as a complex containing many components, which may originate from different functional brain sites; these components can be distinguished according to their respective latencies and amplitudes and are extracted simultaneously by multiple-input single-output autoregressive modeling with exogenous input (MISO-ARX). The extraction process is performed in three stages: first, we use a reference EP as a template and decompose it into a set of components, which serve as subtemplates for the remaining steps. Then, a dictionary is constructed with these subtemplates, and EPs are preliminarily extracted by sparse coding in order to roughly estimate the latency of each component. Finally, the single-trial measurement is parametrically modeled by MISO-ARX while characterizing spontaneous electroencephalographic activity as an autoregression model driven by white noise and with each component of the EP modeled by autoregressive-moving-average filtering of the subtemplates. Once optimized, all components of the EP can be extracted. Compared with ARX, our method has greater tracking capabilities of specific components of the EP complex as each component is modeled individually in MISO-ARX. We provide exhaustive experimental results to show the effectiveness and feasibility of our method

Experimental Study on Motion Behavior and Longitudinal Stability Assessment of a Trimaran Planing Hull Model in Calm Water

In this study, a high-speed planing trimaran hull form is designed, and the effects of different displacements and gravity longitudinal layouts on the performance of the trimaran planing hull in calm water are experimentally investigated in the towing tank of the China Special Vehicle Research Institute. Based on previous work, an innovative inner tunnel appendage hydroflap is mounted in the inner aft tunnel, located 1/8 L from the transom in the longitudinal direction with attack angles of 0° and 4°, respectively. Furthermore, a regular stern flap is mounted on the transom close to the chine. The towing test results show that, as the gravity center moves forward, the high-speed region resistance of the planing trimaran increases and the longitudinal stability is also strengthened. Further, the total resistance of the planing trimaran with a heavier displacement is larger while the average mass resistance declines; i.e., the resistance efficiency is improved. The results also indicate that the inner tunnel hydroflap and stern flap enhance the aft hull hydrodynamic lift and tunnel aerodynamic lift. As a result, mounting aft hull lift enhancement appendages can affect the bottom and inner tunnel pressure distribution and then cause a slight resistance decrease in the low-speed region. The value relationship of resistance between groups of appendages for the attached hull and bare hull is reversed at a speed of about Froude number 3.0. Although the aft hull lift enhancement appendages result in a higher resistance cost in the high-speed region, the longitudinal stability is effectively promoted and the occurrence speed of porpoising results in a delay of 1 to 2 m/s

Experimental Study on Motion Behavior and Longitudinal Stability Assessment of a Trimaran Planing Hull Model in Calm Water

In this study, a high-speed planing trimaran hull form is designed, and the effects of different displacements and gravity longitudinal layouts on the performance of the trimaran planing hull in calm water are experimentally investigated in the towing tank of the China Special Vehicle Research Institute. Based on previous work, an innovative inner tunnel appendage hydroflap is mounted in the inner aft tunnel, located 1/8 L from the transom in the longitudinal direction with attack angles of 0° and 4°, respectively. Furthermore, a regular stern flap is mounted on the transom close to the chine. The towing test results show that, as the gravity center moves forward, the high-speed region resistance of the planing trimaran increases and the longitudinal stability is also strengthened. Further, the total resistance of the planing trimaran with a heavier displacement is larger while the average mass resistance declines; i.e., the resistance efficiency is improved. The results also indicate that the inner tunnel hydroflap and stern flap enhance the aft hull hydrodynamic lift and tunnel aerodynamic lift. As a result, mounting aft hull lift enhancement appendages can affect the bottom and inner tunnel pressure distribution and then cause a slight resistance decrease in the low-speed region. The value relationship of resistance between groups of appendages for the attached hull and bare hull is reversed at a speed of about Froude number 3.0. Although the aft hull lift enhancement appendages result in a higher resistance cost in the high-speed region, the longitudinal stability is effectively promoted and the occurrence speed of porpoising results in a delay of 1 to 2 m/s

Numerical Simulation of the Ducted Propeller and Application to a Semi-Submerged Vehicle

The self-propulsion test of underwater vehicles is the key technique for predicting and evaluating the navigation performance of these submersibles. In this study, the numerical simulation of a standard propeller JD7704+Ka4-70 is first presented and the results are compared with experiments to validate the numerical approaches. The reason why the propulsion efficiency of the ducted propeller is higher than that of the conventional propeller is explored. Then, the paper proposes a series of numerical simulations conducted to test the performance of the ducted propeller designed according to the JD7704+Ka4-70 in order to match with the unmanned semi-submerged vehicle (USSV), and the propeller’s open water characteristic curves are obtained. The results show a reasonable agreement with the regression analysis. Afterwards, the numerical simulations focus on a self-propulsion test of the USSV with the designed ducted propeller and the self-propulsion point is obtained. The streamlines through the hull as well as the ducted propellers are clearly obtained, together with the velocity distributions of the propeller plane. The results vividly demonstrate the hydrodynamic performance of the USSV with the designed propellers. In this paper, all the CFD simulations are based on the numerical software, Star-CCM+, and use the Reynolds-averaged Navier‒Stokes (RANS) equations with the shear stress transport (SST) k-omega turbulence model

Numerical Simulation of the Ducted Propeller and Application to a Semi-Submerged Vehicle

The self-propulsion test of underwater vehicles is the key technique for predicting and evaluating the navigation performance of these submersibles. In this study, the numerical simulation of a standard propeller JD7704+Ka4-70 is first presented and the results are compared with experiments to validate the numerical approaches. The reason why the propulsion efficiency of the ducted propeller is higher than that of the conventional propeller is explored. Then, the paper proposes a series of numerical simulations conducted to test the performance of the ducted propeller designed according to the JD7704+Ka4-70 in order to match with the unmanned semi-submerged vehicle (USSV), and the propeller’s open water characteristic curves are obtained. The results show a reasonable agreement with the regression analysis. Afterwards, the numerical simulations focus on a self-propulsion test of the USSV with the designed ducted propeller and the self-propulsion point is obtained. The streamlines through the hull as well as the ducted propellers are clearly obtained, together with the velocity distributions of the propeller plane. The results vividly demonstrate the hydrodynamic performance of the USSV with the designed propellers. In this paper, all the CFD simulations are based on the numerical software, Star-CCM+, and use the Reynolds-averaged Navier‒Stokes (RANS) equations with the shear stress transport (SST) k-omega turbulence model

Motion Prediction of Catamaran with a Semisubmersible Bow in Wave

Compared with standard vessels, a slender catamaran with a semi-submerged bow (SSB) demonstrates superior seakeeping performance. To predict the motion of an SSB catamaran, computational fluid dynamics methods are adopted in this study and results are validated through small-scale model tests. The pitch, heave, and vertical acceleration are calculated at various wavelengths and speeds. Based on the overset grid and motion region methods, this study obtains the motion responses of an SSB catamaran in regular head waves. The results of the numerical studies are validated with the experimental data and show that the overset grid method is more accurate in predicting the motion of an SSB catamaran; the errors can be controlled within 20%. The movement data in regular waves shows that at a constant speed, the motion response initially increases and then decreases with increasing wavelength. This motion response peak is due to the encountering frequency being close to the natural frequency. Under identical sea conditions, the motion response increases with the increasing Froude number. The motion prediction results, that derive from a short-term irregular sea state, show that there is an optimal speed range that can effectively reduce the amplitude of motion