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  • Open Access


    Trajectory of right ventricular indices is an early predictor of outcomes in hypoplastic left heart syndrome

    Andrew S. Kim1, Colleen M. Witzenburg2, Mark Conaway3, Jeffrey E. Vergales1, Jeffrey W. Holmes2,4, Thomas J. L’Ecuyer1, Peter N. Dean1

    Congenital Heart Disease, Vol.14, No.6, pp. 1185-1192, 2019, DOI:10.1111/chd.12834

    Abstract Background: Children with hypoplastic left heart syndrome (HLHS) have risk for mortality and/or transplantation. Previous studies have associated right ventricular (RV) indices in a single echocardiogram with survival, but none have related serial measurements to outcomes. This study sought to determine whether the trajectory of RV indices in the first year of life was associated with transplant‐free survival to stage 3 palliation (S3P).
    Methods: HLHS patients at a single center who underwent stage 1 palliation (S1P) between 2000 and 2015 were reviewed. Echocardiographic indices of RV size and function were obtained before and following S1P and stage 2 palliation (S2P).… More >

  • Open Access


    Intent Inference Based Trajectory Prediction and Smooth for UAS in Low-Altitude Airspace with Geofence

    Qixi Fu1, Xiaolong Liang1, 2, Jiaqiang Zhang1, *, Xiangyu Fan1, 2

    CMC-Computers, Materials & Continua, Vol.63, No.1, pp. 417-444, 2020, DOI:10.32604/cmc.2020.07044

    Abstract In order to meet the higher accuracy requirement of trajectory prediction for Unmanned Aircraft System (UAS) in Unmanned Aircraft System Traffic Management (UTM), an Intent Based Trajectory Prediction and Smooth Based on Constrained State-dependent-transition Hybrid Estimation (CSDTHE-IBTPS) algorithm is proposed. Firstly, an intent inference method of UAS is constructed based on the information of ADS-B and geofence system. Moreover, a geofence layering algorithm is proposed. Secondly, the Flight Mode Change Points (FMCP) are used to define the relevant mode transition parameters and design the guard conditions, so as to generate the mode transition probability matrix and establish the continuous state-dependent-transition… More >

  • Open Access


    Optimal Coverage Multi-Path Scheduling Scheme with Multiple Mobile Sinks for WSNs

    Jin Wang1, 2, 3, Yu Gao2, Chang Zhou2, R. Simon Sherratt4, Lei Wang5, *

    CMC-Computers, Materials & Continua, Vol.62, No.2, pp. 695-711, 2020, DOI:10.32604/cmc.2020.08674

    Abstract Wireless Sensor Networks (WSNs) are usually formed with many tiny sensors which are randomly deployed within sensing field for target monitoring. These sensors can transmit their monitored data to the sink in a multi-hop communication manner. However, the ‘hot spots’ problem will be caused since nodes near sink will consume more energy during forwarding. Recently, mobile sink based technology provides an alternative solution for the long-distance communication and sensor nodes only need to use single hop communication to the mobile sink during data transmission. Even though it is difficult to consider many network metrics such as sensor position, residual energy… More >

  • Open Access


    Improvement of Flat Surfaces Quality of Aluminum Alloy 6061-O By a Proposed Trajectory of Ball Burnishing Tool

    Ruba Alghazoul1, Almohanad Makki1, Magd Abdel Wahab2,3,*

    CMC-Computers, Materials & Continua, Vol.61, No.2, pp. 555-568, 2019, DOI:10.32604/cmc.2019.06337

    Abstract Burnishing is a profitable process of surface finishing due to its ability to be automated, which makes burnishing method more desirable than other finishing methods. To obtain high surface finish, non-stop operation is required for CNC machine and we can attain that by choosing a suitable trajectory of the finishing tool. In other words, burnishing paths should be multidirectional rather than monotonic, in order to cover uniformly the surface. Indeed, the burnishing force is also a key parameter of the burnishing process because it determines the degree of plastic deformation, and that makes determining the optimum burnishing force an essential… More >

  • Open Access


    Ship Trajectory Prediction Based on BP Neural Network

    Hai Zhou1,2,*, Yaojie Chen1,2, Sumin Zhang3

    Journal on Artificial Intelligence, Vol.1, No.1, pp. 29-36, 2019, DOI:10.32604/jai.2019.05939

    Abstract In recent years, with the prosperity of world trade, the water transport industry has developed rapidly, the number of ships has surged, and ship safety accidents in busy waters and complex waterways have become more frequent. Predicting the movement of the ship and analyzing the trajectory of the ship are of great significance for improving the safety level of the ship. Aiming at the multi-dimensional characteristics of ship navigation behavior and the accuracy and real-time requirements of ship traffic service system for ship trajectory prediction, a ship navigation trajectory prediction method combining ship automatic identification system information and Back Propagation… More >

  • Open Access


    An Algorithm for Mining Gradual Moving Object Clusters Pattern From Trajectory Streams

    Yujie Zhang1, Genlin Ji1,*, Bin Zhao1, Bo Sheng2

    CMC-Computers, Materials & Continua, Vol.59, No.3, pp. 885-901, 2019, DOI:10.32604/cmc.2019.05612

    Abstract The discovery of gradual moving object clusters pattern from trajectory streams allows characterizing movement behavior in real time environment, which leverages new applications and services. Since the trajectory streams is rapidly evolving, continuously created and cannot be stored indefinitely in memory, the existing approaches designed on static trajectory datasets are not suitable for discovering gradual moving object clusters pattern from trajectory streams. This paper proposes a novel algorithm of gradual moving object clusters pattern discovery from trajectory streams using sliding window models. By processing the trajectory data in current window, the mining algorithm can capture the trend and evolution of… More >

  • Open Access


    Trajectory Planning of High Precision Collaborative Robots

    Tuanjie Li1,*, Yan Zhang1, Jiaxing Zhou1

    CMES-Computer Modeling in Engineering & Sciences, Vol.118, No.3, pp. 583-598, 2019, DOI:10.31614/cmes.2018.04891

    Abstract In order to satisfy the high efficiency and high precision of collaborative robots, this work presents a novel trajectory planning method. First, in Cartesian space, a novel velocity look-ahead control algorithm and a cubic polynomial are combined to construct the end-effector trajectory of robots. Then, the joint trajectories can be obtained through the inverse kinematics. In order to improve the smoothness and stability in joint space, the joint trajectories are further adjusted based on the velocity look-ahead control algorithm and quintic B-spline. Finally, the proposed trajectory planning method is tested on a 4-DOF serial collaborative robot. The experimental results indicate… More >

  • Open Access


    A Trajectory Planning-Based Energy-Optimal Method for an EMVT System

    Jiayu Lu1, Siqin Chang1,*

    CMES-Computer Modeling in Engineering & Sciences, Vol.118, No.1, pp. 91-109, 2019, DOI:10.31614/cmes.2019.04190

    Abstract In this paper, a trajectory planning-based energy-optimal method is proposed to reduce the energy consumption of novel electromagnetic valve train (EMVT). Firstly, an EMVT optimization model based on state equation was established. Then, the Gauss pseudospectral method (GPM) was used to plan energy-optimal trajectory. And a robust feedforward-feedback tracking controller based on inverse system method is proposed to track the energy-optimal trajectory. In order to verify the effectiveness of the energy-optimal trajectory, a test bench was established. Finally, co-simulations based on MATLAB Simulink and AVL Boost were carried out to illustrate the effect of energy-optimal trajectories on engine performance. Experimental… More >

  • Open Access


    Permissible Wind Conditions for Optimal Dynamic Soaring with a Small Unmanned Aerial Vehicle

    Liu Duo-Neng1,2, Hou Zhong-Xi1, Guo Zheng1, Yang Xi-Xiang1, Gao Xian-Zhong1

    CMES-Computer Modeling in Engineering & Sciences, Vol.111, No.6, pp. 531-565, 2016, DOI:10.3970/cmes.2016.111.531

    Abstract Dynamic soaring is a flight maneuver to exploit gradient wind field to extend endurance and traveling distance. Optimal trajectories for permissible wind conditions are generated for loitering dynamic soaring as well as for traveling patterns with a small unmanned aerial vehicle. The efficient direct collection approach based on the Runge-Kutta integrator is used to solve the optimization problem. The fast convergence of the optimization process leads to the potential for real-time applications. Based on the results of trajectory optimizations, the general permissible wind conditions which involve the allowable power law exponents and feasible reference wind strengths supporting dynamic soaring are… More >

  • Open Access


    Long Endurance and Long Distance Trajectory Optimization for Engineless UAV by Dynamic Soaring

    B. J. Zhu1,2, Z. X. Hou1, X. Z. Wang3, Q. Y. Chen1

    CMES-Computer Modeling in Engineering & Sciences, Vol.106, No.5, pp. 357-377, 2015, DOI:10.3970/cmes.2015.106.357

    Abstract The paper presents a comprehensive study on the performance of long endurance and long distance trajectory optimization of engineless UAV in dynamic soaring. A dynamic model of engineless UAV in gradient wind field is developed. Long endurance and long distance trajectory optimization problems are modelled by non-linear optimal control equations. Two different boundary conditions are considered and results are compared: (i) open long endurance pattern, (ii) closed long endurance pattern, (iii) open long distance pattern. In patterns of (i) and (ii), the UAV return to original position with the maximum flying time in pattern (ii) , and in patterns of… More >

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