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Objectives: To investigate the characteristics of ecological executive function in patients with Parkinson’s disease（PD）.Methods: Thirty-three patients who were diagnosed as PD according to the Diagnostic Criteria of Parkinson’s Disease in China（2016） and 35 elder individuals without cognitive impairment were recruited. The Chinese version of 10-Item Weekly Calendar Planning Activity（WCPA-10） was conducted to evaluate ecological executive function. Between-group variance and correlation between indices of WCPA-10 in PD group was analyzed. Results: In WCPA-10,the performance on efficiency, accurate entered appointment, followed rules, error type, time awareness, accuracy estimation were significantly worse in PD group than in normal cognition group（P<0.05）.Total time and planning time 2 were highly correlated（r=0.72,P <0.01）,moderate correlation was found between entered appointment and accurate entered appointment, efficiency and total time, planning time 1 and2,planning time 1 and total time, strategy use and accurate entered appointment（r>0.52,Ps <0.01）.Conclusion:Patients with Parkinson’s disease may have significant deficits in ecological executive function compared with elder adults without cognitive impairment. The involved cognitive components are inhibitory control, working memory, and self-awareness. [ABSTRACT FROM AUTHOR]

The quality of case base would affect the convergence effect of CB-HAQL algorithm strategy. Aiming at the fact, this paper developed an improved CB-HAQL algorithm based on effective triggering mechanism. Firstly, the algorithm set the trigger case base update mechanism according to the number of iterations. In order to ensure the quality of the case base, only when the threshold was reached, the algorithm generated or update the case base. Secondly, the dynamic parameter was set to adjust the impact of the case on action selection, so that the agent could determine the size of heuristic influence according to the degree of mastery of the environment. Finally, the algorithm added experience-oriented exploratory action to accelerate the learning efficiency. Experiments show that the algorithm improves the strategy quality and training speed, and the UAV' s navigation task proves the effectiveness of learning strategy. [ABSTRACT FROM AUTHOR]

Aiming at the lack of consideration of realistic influencing factors and directionality of road sections in the critical road sections of urban traffic road network identification based on complex networks, this paper proposed an identification method of critical road sections based on weighted and directed complex networks. At the first stage, it employed the complex network theory to construct the urban traffic road network as a weighted and directed complex network model. At the second stage, it employed LinkRank algorithm to sort the importance of edges in complex networks, and identified the critical edges by sorting result, which was the critical sections of urban traffic road network. At the third stage, it employed the variant susceptible-infective (SI) model to evaluate the impact of critical road sections. Through the analysis of the urban traffic road network in Haining city, it verifies the practicability and effectiveness of the proposed method. [ABSTRACT FROM AUTHOR]

Aiming to realize the obstacle avoidance of fruit harvesting robot manipulator in unstructured environments, a kind of obstacle avoidance path planning algorithm of hybrid harvesting manipulator based on joint configuration space was proposed in this study. The structure of the 2P4R hybrid camellia oleifera fruit harvesting robot manipulator composed of a palletizing manipulator and a spherical wrist serial manipulator was simplified, and the link connecting the palletizing manipulator and serial manipulator was named as moving platform. The manipulator could accomplish six kinds of movements, including waist rotation, translational motions of vertical slider and horizontal slider, as well as three kinds of rotational motions of the wrist part. In this study, only five joint motions were taken into consideration. It meant that the last link was considered as a fixed part of its previous link when a collision-free path planning operation was conducted. This was because the motion of the last link was not related to the position of end effector which could only affect its posture. Firstly, a goal point for the moving platform of the manipulator in Cartesian space was selected with the proposed algorithm. The goal point should be located in workspace of the parallel manipulator, rather than inside obstacles. The initial and goal configurations of serial manipulator were determined by the moving platform of the goal point, the goal position of end effector and initial posture of serial manipulator. Secondly, the obstacle mapping model in serial manipulator joint configuration space was built with traversal method. Then, an attempt was made to search for a collision-free route from initial point to the goal point in this space with each point uniquely corresponding to a configuration of the serial manipulator by using rapid-exploring random tree (RRT) algorithm. Thirdly, if the algorithm failed to find such a route in previous step, the selection of goal point and collision-free route searching operation would be repeated. Otherwise, joint configuration space of parallel manipulator would be established. Fourthly, the unique posture of parallel manipulator was determined based on the mapping relationship between driving joint value and position coordinates of moving platform. The obstacle model was built in the joint configuration space of parallel manipulator. Subsequently, the goal point of the moving platform would be selected again, if the point in parallel manipulator configuration space corresponding to the goal configuration was located in mapping model of obstacle. Otherwise, a collision-free route from the start point to the goal point in configuration space corresponding to initial posture and goal configuration of the parallel manipulator respectively should be searched by using RRT algorithm. The obstacle avoidance path of hybrid manipulator was obtained from synthesized results of collision-free paths of serial manipulator and parallel manipulator. In order to verify the feasibility and effectiveness of the proposed algorithm, path planning simulation of a hybrid manipulator using Matlab was carried out. Proposed algorithm was also applied in obstacle avoidance path planning experiment on camellia oleifera fruit harvesting manipulator. According to the simulation and experiment results, path planned by the proposed algorithm could successfully drive the end effector from its initial position to the goal position without any collision. That is to say, these results can validate the feasibility and effectiveness of the proposed algorithm. [ABSTRACT FROM AUTHOR]

Objective To investigate whether there is a mediating effect of cognitive function between social participation and frailty. Methods Using the China Health and Retirement Longitudinal Survey (CHARLS) database, three rounds of survey data in 2011, 2013, and 2015 were selected for the study. The data in 2011 were the baseline data, and the ID number was used to match the participants in the follow-up in 2013 and 2015. A total of 3 139 people were enrolled in this cohort study. Cox regression model and simple mediating effect model were used to analyze the relationship among social participation, cognitive function, and frailty. Results A total of 259 patients had frailty during the follow -up period. The results of multivariate Cox regression model adjusting social demography and lifestyle showed that social participation (ffl =0.641, 95% CI: 0.496-0.829) and cognitive function (HR=0.952, 95%CI: 0.928-0.977) were associated with frailty. The results of the intermediary model with relevant covariates showed that cognitive function has a significant mediating effect between social participation and frailty. Conclusion Social participation and cognitive function are associated with frailty, and cognitive function has some mediating effect between social participation and frailty. [ABSTRACT FROM AUTHOR]

In order to improve resource utilization efficiency in wireless sensor network, this paper proposed an algorithm to allocate tasks to a pair of collaboratively working sensor nodes based on their link quality. Specifically, it utilized link quality of two collaborative nodes to obtain the ability level of them. Then, allocated each node pair with a task whose task level ( e . g., measured by the computing intensity) could match with the ability level of this node pair, so that each node pair could perform task cooperatively and efficiently. Considering that a node may form different node pairs with multiple nod es, thus allocating redundant tasks( tasks with same task level), algorithm need to adjusted tasks to avoid redundant task execution. Simulation results show that the proposed algorithm can not only improve the task allocation efficiency, but also balance the energy consumption of wireless sensor network. [ABSTRACT FROM AUTHOR]

In the process of developing picking robot prototype, the traditional picking tests are usually performed in orchard, which are limited by certain factors such as the harvesting season, weather condition and venue. So, the investigated and designed algorithm for the vision and control system of picking robots can't be verified effectively and timely, and the prototype development cycle has to last longer. To test the vision and control algorithm of picking robot, a hardware-in-the-loop virtual experimental system based on binocular stereo vision for grape-picking robot was designed in this paper, which was composed of hardware and software units. The hardware units consisted of binocular camera, grape clusters, grape imitative leaf and stems, support structure of grape clusters and its guide rail, calibration board, and so on. The software units included vision processing part and virtual picking robot. Firstly, the spatial information such as the picking point and the anti-collision bounding volume of the grape cluster was extracted by binocular stereo vision. The picking point on the peduncle of the grape cluster was detected by using a minimum distance restraint between the barycentre of the pixel region of grape cluster and the detected lines in the ROI (region of interest) of peduncle. The anti-collision bounding volume of the grape cluster was calculated by transforming the spatial coordinates of the picking point and all detected grape berries into the coordinate system of grape clusters. Secondly, the three-dimensional models of the picking robot were constructed according to the picking robot prototype with 6 degrees of freedom which already existed in our laboratory. The Denavit-Hartenberg (D-H) method was adopted to establish the robot coordinate transformation. The direct and inverse solutions of the robot kinematics were solved by using the inverse transformation method, and then the only inverse solution was obtained. Thirdly, the moving path of picking robot was planned based on the artificial potential field theory. The collision between the robot manipulator and the grape clusters in the virtual environment was detected by using the hierarchical bounding box algorithm which can validate the reasonability of path planning. The motion simulation of the virtual picking robot was programmed by combining the modular programming and the routing communication mechanism. Finally, the spatial information of the grape clusters was extracted by programming the application code using Visual C++ and OpenCV (open source computer vision library), and the path planning and the motion simulation of the virtual picking robot were performed based on the virtual reality platform EON, Visual C++ and JavaScript. The hardware-in-the-loop virtual experimental platform was established by combining the binocular stereo vision and virtual picking robot. On this platform, 34 tests were performed by changing the position of the grape clusters under laboratory environment while the binocular cameras kept still. And every test included 3 steps, the first step was vision locating, the second was path planning and the last was clamping and cutting operation. In all the tests, 29 tests were successful in vision locating, and 5 tests were failed in vision locating. Among those 5 failed tests, 2 tests were wrong in picking point detection and 3 tests were failed in stereo matching on the picking point. There was one test failed in path planning when the grape clusters were located correctly, and all of the clamping and cutting operation for the grape clusters ran smoothly when the anti-collusion path was planned successfully. In general, the success rates of the tests on visual localization, path planning, clamping and cutting operation were 85.29%, 82.35%, 82.35%, respectively. The results showed that the method developed in this study can be used to verify and test the visual location and behavior algorithm of the picking robot, and then provide the support to the harvesting robot development, test and continuous improvement. [ABSTRACT FROM AUTHOR]

The random error caused by disturbance is the bottleneck of vision positioning of harvesting manipulator. In order to improve the work-efficiency and positioning accuracy of litchi harvesting manipulator, the precise positioning of litchi picking point was studied. Firstly, a binocular stereo vision and an added vibration table to simulate external force disturbance were used to detect the picking point coordinates. The experiment was conducted using the mechanism and the vision-positioning experimental platform based on binocular vision in laboratory. The cameras used in the test and that on the manipulator were the same. The vibration table created perturbation in three coordinate directions. The corresponding perturbation was close to that when conducting outdoor work in a dynamic environment (such as mechanism vibration or wind). A calibration plate was used as a reference to detected positions in the horizontal direction, and a laser rangefinder was used to measure ground truth in the depth direction. The accuracy reported by the specs of calibration plate and laser rangefinder were ±0.2 mm and ±1 mm, respectively. After measuring the ground-truth position, the errors were calculated. Secondly, an error analysis scheme was proposed. The errors resulting from vision positioning system were divided into original positioning and random positioning errors according to the change rules. The positioning errors under static conditions were regarded as original positioning errors. Random positioning errors were resulted from the influence of unknown external forces. Finally, the quantitative analysis and evaluation of the errors were separately determined by statistical methods. The results showed that the variation trend of original positioning errors was basically consistent with random positioning errors in the distance of 600 to 1000 m. The maximum errors obtained were 58.8 in vision depth direction and 17.3 mm in horizontal direction. The positioning precision in horizontal direction was high. Errors in vision depth direction were considerably larger than errors in horizontal direction. The original error achieved a narrow confidence interval. The original positioning errors in vision depth direction and distances were linear, while the errors in horizontal direction were nonlinear. The random positioning errors under dynamic environment were normally distributed. The random positioning errors in vision depth direction had no obvious connection with errors in horizontal direction. The random positioning errors in vision depth direction, which were greatly influenced by the disturbance, showed a low positioning accuracy and were worse than the errors in horizontal direction. So the disturbance restraint in vision depth direction should be improved. The experiment results can be used to calibrate vision system and layout the vision positioning scheme under dynamic environment. Meanwhile, a mathematical model of error tolerance was established. As the existing end-effectors cannot conduct error tolerance for random error, it also provided a theoretical basis for error -tolerant design of fruit-picking end-effector. Indoor positioning and grasping experiments were conducted for litchi using the manipulator based on the binocular vision. The picking success rate was over 90%. The results verified the applicability of the error-tolerant design. In summary, a precise positioning measurement was proposed based on institutions and vision positioning, and random positioning error could be compensated for by the mechanism of error tolerance. [ABSTRACT FROM AUTHOR]