学　术

　　为搭建我校博士后学术交流平台，促进学术水平提升，学校博士后管理办公室组织开展博士后学术沙龙活动。本次沙龙由我校自动化工程学院承办，邀请博士后姜忠、于文杰、施孟佶、刘东分享其研究成果，诚邀感兴趣的师生参加。

　　一、时　间：2018年5月25日（周五）10：00

　　二、地　点：清水河校区经管楼宾诺咖啡

　　三、活动安排：

　　报告一：

　　主　题：Brief Introduction of a new test specimen for the five-axis machine tool machining performance

　　主讲人：姜忠　机械与电气工程学院博士后

　　交流内容：

　　Five-axis CNC machines are widely used in the processing of complex space surfaces such as aircraft parts and marine propeller because of the excellent spatial accessibility. In the manufacture of aerospace, shipbuilding and high precision instruments, the five-axis CNC machining level has become an important symbol showing the manufacturing industry level in a country. In order to guarantee the five-axis machine's processing ability of the complex surface, a new test specimen, S-test piece, has been presented to satisfy the increasing demand of a five-axis machine. In this talk, the model of S part is described in detail which presents more characteristics in three-dimensional surface contours. Then the relationship between the geometric characteristics and the contour errors caused by the machine tool is discussed. Finally, some cutting experiments are carried out on the five-axis machine tool to verify the superiority of S test piece.

　　主讲人简介：

　　Zhong Jiang received the B.S. and the Ph.D. degrees in 2011 and 2017, respectively, both in University of Electronic Science and Technology of China (UESTC). He currently works as a Postdoctoral Fellow in the School Mechanical and Electrical Engineering. His research interests include intelligent manufacture, precision detection and fault diagnosis for advanced manufacturing equipment.

　　报告二：

　　主　题：Using an Improved Artificial Bee Colony on Relay Nodes Deployment of Two Tiered Wireless Sensor Networks

　　主讲人：于文杰  自动化工程学院博士后

　　交流内容：

　　As the core infrastructures of Internet of Things and big data, wireless sensor networks (WSNs) have been extensively researched and applied in recent years. The optimal nodes deployment is a basic problem that affects many attributes of all WSNs. The deployment problems are divided into two categories: single tiered and two tiered. The two tiered deployment can form a network skeleton relative to the single tiered deployment, further extending the network lifetime. However, the relay nodes deployment problem of the two tiered network is NP-Hard. Meta-heuristic algorithms based on swarm intelligence can solve such problems effectively. Among them, artificial bee colony algorithm is an emerging meta-heuristic algorithm based on swarm intelligence. Because of its characteristics of strong global optimization ability and easy implementation, it displays certain advantages for solving complex nonlinear optimization problems. However, the artificial bee colony algorithm has problems such as slow convergence speed and insufficient compatibility of the problem, so it needs to be studied in-depth and then applied to the two-tiered relay node deployment problems. In this talk, we first give a brief introduction to WSNs and artificial bee colony algorithm. Then a two-tier network deployment problem model definition is given. An improved artificial bee colony algorithm is introduced and applied to test the benchmark function and tackle the two tiered relay nodes deployment simulation. Finally, the real experimental verification analysis is given.

　　主讲人简介：

　　Wenjie Yu received the Bachelor degree from Northwest A&F University and Ph.D. degree from University of Electronic Science and Technology of China (UESTC), in 2011 and 2017, respectively. He currently works as a Postdoctoral Fellow in the School of Automation Engineering of UESTC. Dr. Yu is working in the field of wireless sensor network (WSN). His main research interests include deployment of WSN; swarm intelligence; application of AI in calibration of instrument; industrial sensing cloud.

　　报告三：

　　主　题：Cooperative Multi-Vehicle Sweep Coverage Control for Unknown Areas of Irregular Shape

　　主讲人：施孟佶　航空航天学院博士后

　　交流内容：

　　Various civil and military missions, such as rescue search, disaster monitoring and surveillance, require complete coverage of certain areas by multiple unmanned vehicles for safety and efficiency. The regions to be covered are usually of unknown irregular shape, thus it is infeasible to preplan the path. On the other hand, collision avoidance, limited mobility and cooperation of the vehicles should be considered. To solve the problem, a novel multi-vehicle area coverage control scheme will be shared in this talk. After briefly introducing basic principles of multi-vehicle cooperation and recently proposed coverage methods, we first formulate the coverage control problems and set standards of detection and task execution performance for each vehicle. Inspired by the motion of a string of balls connected by springs, a solution then is displayed along with a heuristic model explaining its physical sense. Further, we apply the control algorithm to a group of vehicles with second-order dynamics, and examine its effectiveness by numerical simulations. Finally, we discuss the applicability of the method, and make comparisons with the others.

　　主讲人简介：

　　Mengji Shi received the M.S. and Ph.D. degrees from University of Electronic Science and Technology of China (UESTC) in 2011 and 2017, respectively. He currently works as a Postdoctoral Fellow in the School of Aeronautics and Astronautics of UESTC. His research interests include collective behavior of multi-agent systems, cooperation of unmanned vehicles, distributed control of wireless sensor networks, and data processing for vehicle motion guidance.

　　报告四：

　　主　题：Passive wireless piezoelectric sensor in stress measurement

　　主讲人：刘东　自动化工程学院博士后

　　交流内容：

　　In this talk, we briefly discuss the stress measurement of piezoelectric sensor. There are three issues are decoupling of multi parameter coupling effect of piezoelectric sensor， measurement of the equivalent electrical parameters of a piezoelectric resonator and passive wireless stress measurement respectively.

　　Firstly, we investigate the multi parameter coupling effect of piezoelectric resonators, and analysis the main coupling parameters of the stress sensing: temperature and stress. we are focusing on the trim effect caused by nonlinearity of temperature sensing.

　　Then, we discuss the method of decouple multi parameter coupling effect: multi parameter measurement, that is, the measurement of the equivalent electrical parameters of piezoelectric resonators. The shortcomings of the method given by International Electrotechnical Commission (IEC) will be discuses. It includes resonant resistance approximate dynamic resistance, the static capacitance is the value of the capacitance at a non-resonant frequency and so on. Next, we will give a method measuring equivalent parameter based on phase frequency curve.

　　Finally, we explore the possibility of applying our method in the field on passive wireless stress measurement. Impedance measurement method based on mutual inductance model will be discussed. The factors that will affect the measurement results will also be discussed.

　　主讲人简介：

　　D. Liu received the Bachelor degree from Sichuan University and Ph.D. degree from UESTC respectively. He currently works as a Postdoctoral Fellow in the School of Automation Engineering of UESTC. Dr. Liu is working in the field of piezoelectric sensors. His main research interests include decoupling of multi parameter coupling effect of piezoelectric sensor; thermal hysteresis effect of piezoelectric sensor; passive wireless sensor.

　　四、主办单位：电子科技大学博士后管理办公室

　　　　承办单位：自动化工程学院

　　　　　　　　　　　　　　　　　电子科技大学博士后管理办公室

　　　　　　　　　　　　　　　　　　　　 2018年5月21日