A systematic analysis of correlations between different orders of p T -differential flow is presented, including mode coupling effects in flow vectors, correlations between flow angles (a.k.a. eventplane correlations), and correlations between flow magnitudes, all of which were previously studied with integrated flows. We find that the mode coupling effects among differential flows largely mirror those among the corresponding integrated flows, except at small transverse momenta where mode coupling contributions are small. For the fourth-and fifth-order flow vectors V 4 and V 5 we argue that the event plane correlations can be understood as the ratio between the mode coupling contributions to these flows and the flow magnitudes. We also find that for V 4 and V 5 the linear response contribution scales linearly with the corresponding cumulant-defined eccentricities but not with the standard eccentricities. * Correspond to qianjing8758@gmail.com

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This paper presents a modeling approach to feature classification and environment mapping for indoor mobile robotics via a rotary ultrasonic array and fuzzy modeling. To compensate for the distance error detected by the ultrasonic sensor, a novel feature extraction approach termed “minimum distance of point” (MDP) is proposed to determine the accurate distance and location of target objects. A fuzzy model is established to recognize and classify the features of objects such as flat surfaces, corner, and cylinder. An environmental map is constructed for automated robot navigation based on this fuzzy classification, combined with a cluster algorithm and least-squares fitting. Firstly, the platform of the rotary ultrasonic array is established by using four low-cost ultrasonic sensors and a motor. Fundamental measurements, such as the distance of objects at different rotary angles and with different object materials, are carried out. Secondly, the MDP feature extraction algorithm is proposed to extract precise object locations. Compared with the conventional range of constant distance (RCD) method, the MDP method can compensate for errors in feature location and feature matching. With the data clustering algorithm, a range of ultrasonic distances is attained and used as the input dataset. The fuzzy classification model—including rules regarding data fuzzification, reasoning, and defuzzification—is established to effectively recognize and classify the object feature types. Finally, accurate environment mapping of a service robot, based on MDP and fuzzy modeling of the measurements from the ultrasonic array, is demonstrated. Experimentally, our present approach can realize environment mapping for mobile robotics with the advantages of acceptable accuracy and low cost.

Using a multi-phase transport (AMPT) model, we investigate the effect of partonic cascade on two-pion HBT parameters of the core-halo source in relativistic heavy-ion collisions. The evolution time as a function of the partonic cross section for Au+Au central collisions at = s 200 NNGeV shows that the evolution time of the pion emission source is decreased with an increasing partonic cross section, and the drop is due to the evolution time of the core. The partonic cascade with a larger cross section leads to a shorter lifetime of the source.