웹캠을 이용한 골프공 인식 및 위치추정 시스템

Zhu Jiaqi,Jiang Chong,김강철 한국전자통신학회 2013 한국전자통신학회 논문지 Vol.8 No.12

A golf ball collecting robot in a golf ball driving range has been recently required because it is safer and more economic than a human being. In this paper, the golf ball recognition and distance estimation system based on a neural network and OpenCV is developed for the robot. The simulation results show that the recognition ratio is over 87% for the distance of less than 120cm and accurate rate for distance estimation is over 85% for golf balls in 30-180cm from a webcam. 골프 연습장에서 골프공 수거 시에 인간보다는 로봇이 사고의 염려가 없고 경제적이어서 골프공 수거 로봇과 골프공 인식 및 위치추적 시스템 개발의 요구가 증가되고 있다. 본 논문에서는 실내 골프 연습장에서 골프공을 수거하는 로봇이 골프공을 인식하고, 위치를 추정할 수 있는 영상처리 알고리즘과 시스템을 OpenCV 를 사용하여 개발하였다. 30-180cm 거리에 위치하는 골프공을 대상으로 실험을 수행하였으며, 120cm 이내에서는 87% 이상의 높은 인식률을 얻었으며, 골프공은 실제 거리의 85% 이내에 위치하였다.

An Improved Density-Based Design Method of Additive Manufacturing Fabricated Inhomogeneous Cellular-Solid Structures

Yu Zhu,Jiaqi Zhao,Ming Zhang,Xin Li,Leijie Wang,Chuxiong Hu 한국정밀공학회 2020 International Journal of Precision Engineering and Vol.21 No.1

Benefited from the rapid development of additive manufacturing (AM), inhomogeneous cellular structures have attracted many interests for their superior structural and functional performance. Recently proposed density-based design methods have been shown to provide great computational efficiency and obtain structures with excellent performance. To achieve better structural performance while considering AM constraints, an improved density-based design method which introduces solid and void units into the design domain is proposed in this paper. First, based on homogenization theory and solid-body analysis, unit parameters of different preset unit relative densities are determined. And a unit effective property interpolation model is constructed. Then, the macro relative density layout is optimized with density methods. In the optimization process, an efficient density filter is proposed to increase the optimization domain and satisfy minimal feature size constraint. Finally, the structure reconstruction algorithm automatically constructs the optimized cellular structure based on the unit and density information obtained in the first two processes. Numerical examples show that the proposed method efficiently obtains inhomogeneous cellular structures with better performance, compared with existing density-based methods.

Progressive Filtering Approach for Early Human Action Recognition

Tehao Zhu,Yue Zhou,Zeyang Xia,Jiaqi Dong,Qunfei Zhao 제어·로봇·시스템학회 2018 International Journal of Control, Automation, and Vol.16 No.5

Human action recognition plays an important role in vision-based human-robot interaction (HRI). In many application scenarios of HRI, robot is required to recognize the human action expressions as early as possible in order to ensure a suitable response. In this paper, we proposed a novel progressive filtering approach to improve the robot’s performance in identifying the ongoing human actions and thus to enhance the fluency and friendliness of HRI. Human movement data were captured by a Kinect device, and then the human actions were constituted by the refined movement data using robust regression-based refinement. Motion primitive, including both spatial and temporal information concerning the movement, was considered as an improved representation of action features. Then, the early human action recognition was accomplished based on an improved locality-sensitive hashing algorithm, by which the ongoing input action can be classified progressively. The proposed approach has been evaluated on four datasets of human actions in terms of accuracy and recall curves. The experiments showed that the proposed progressive filtering approach achieves high recognition rate, and in addition, can make the recognition decision at an earlier stage of the ongoing action.

A Sociable Human-robot Interaction Scheme Based on Body Emotion Analysis

Tehao Zhu,Zeyang Xia,Jiaqi Dong,Qunfei Zhao 제어·로봇·시스템학회 2019 International Journal of Control, Automation, and Vol.17 No.2

Many kinds of interaction schemes for human-robot interaction (HRI) have been reported in recent years. However, most of these schemes are realized by recognizing the human actions. Once the recognition algorithmfails, the robot’s reactions will not be able to proceed further. This issue is thoughtless in traditional HRI, but is thekey point to further improve the fluency and friendliness of HRI. In this work, a sociable HRI (SoHRI) scheme basedon body emotion analysis was developed to achieve reasonable and natural interaction while human actions werenot recognized. First, the emotions from the dynamic movements and static poses of humans were quantified usingLaban movement analysis. Second, an interaction strategy including a finite state machine model was designed todescribe the transition regulations of the human emotion state. Finally, appropriate interactive behavior of the robotwas selected according to the inferred human emotion state. The quantification effect of SoHRI was verified usingthe dataset UTD-MHAD, and the whole scheme was tested using questionnaires filled out by the participants andspectators. The experimental results showed that the SoHRI scheme can analyze the body emotion precisely, andhelp the robot make reasonable interactive behaviors.

틱톡 특성이 인지된 즐거움과 사용 만족도에 미치는 영향 분석 연구: 재한 중국 유학생을 중심으로

주유존(Liucun Zhu),유가기(Jiaqi Liu),황하성(Hasung Hwang) 동국대학교 영상문화콘텐츠연구원 2023 영상문화콘텐츠연구 Vol.28 No.-

Multiple model switching adaptive control for vibration control of cantilever beam with varying load using MFC actuators and sensors

Zhiyuan Gao,Jiaqi Huang,Zhonghua Miao,Xiaojin Zhu 국제구조공학회 2020 Smart Structures and Systems, An International Jou Vol.25 No.5

Vibration at the tip of various flexible manipulators may affect their operation accuracy and work efficiency. To suppress such vibrations, the feasibility of using MFC actuators and sensors is investigated in this paper. Considering the convergence of the famous filtered-x least mean square (FXLMS) algorithm could not be guaranteed while it is employed for vibration suppression of plants with varying secondary path, this paper proposes a new multiple model switching adaptive control algorithm to implement the real time active vibration suppression tests with a new multiple switching strategy. The new switching strategy is based on a cost function with reconstructed error signal and disturbance signal instead of the error signal from the error sensor. And from a robustness perspective, a new variable step-size sign algorithm (VSSA) based FXLMS algorithm is proposed to improve the convergence rate. A cantilever beam with varying tip mass is employed as flexible manipulator model. MFC layers are attached on both sides of it as sensors and actuators. A co-simulation platform was built using ADAMS and MATLAB to test the feasibility of the proposed algorithms. And an experimental platform was constructed to verify the effectiveness of MFC actuators and sensors and the real-time vibration control performance. Simulation and experiment results show that the proposed FXLMS algorithm based multiple model adaptive control approach has good convergence performance under varying load conditions for the flexible cantilever beam, and the proposed FX-VSSA-LMS algorithm based multiple model adaptive control algorithm has the best vibration suppression performance.

Association between the severity of hypodontia and the characteristics of craniofacial morphology in a Chinese population: A cross-sectional study

Xin Xiong,Jiaqi Liu,Yange Wu,Chengxinyue Ye,Qinlanhui Zhang,Yufan Zhu,Wenke Yang,Jun Wang 대한치과교정학회 2023 대한치과교정학회지 Vol.53 No.3

Objective: To investigate craniofacial differences in individuals with hypodontia and explore the relationship between craniofacial features and the number of congenitally missing teeth. Methods: A cross-sectional study was conducted among 261 Chinese patients (males, 124; females, 137; age, 7–24 years), divided into four groups (without hypodontia: no teeth missing, mild: one or two missing teeth, moderate: three to five missing teeth, severe: six or more missing teeth) according to the number of congenitally missing teeth. Differences in cephalometric measurements among the groups were analyzed. Further, multivariate linear regression and smooth curve fitting were performed to evaluate the relationship between the number of congenitally missing teeth and the cephalometric measurements. Results: In patients with hypodontia, SNA, NA-AP, FH-NA, ANB, Wits, ANS-Me/N-Me, GoGn-SN, UL-EP, and LL-EP significantly decreased, while Pog-NB, AB-NP, N-ANS, and S-Go/N-Me significantly increased. In multivariate linear regression analysis, SNB, Pog-NB, and S-Go/N-Me were positively related to the number of congenitally missing teeth. In contrast, NA-AP, FH-NA, ANB, Wits, N-Me, ANS-Me, ANS-Me/N-Me, GoGn-SN, SGn-FH (Y-axis), UL-EP, and LL-EP were negatively related, with absolute values of regression coefficients ranging from 0.147 to 0.357. Further, NA-AP, Pog-NB, S-Go/N-Me, and GoGn-SN showed the same tendency in both sexes, whereas UL-EP and LL-EP were different. Conclusions: Compared with controls, patients with hypodontia tend toward a Class III skeletal relationship, reduced lower anterior face height, flatter mandibular plane, and more retrusive lips. The number of congenitally missing teeth had a greater effect on certain characteristics of craniofacial morphology in males than in females.

Control of a Laboratory 3-DOF Helicopter: Explicit Model Predictive Approach

Ju Zhang,Xinyan Cheng,Jiaqi Zhu 제어·로봇·시스템학회 2016 International Journal of Control, Automation, and Vol.14 No.2

A helicopter flight control system is a typical multi-input, multi-output system with strong channel couplingand nonlinear characteristics. This paper presents an explicit model predictive control (EMPC) for attituderegulation and tracking of a 3-Degree-of-Freedom (3-DOF) helicopter. A state-space representation of the systemis established according to the characteristics of each degree-of-freedom motion. Multi-Parametric Quadratic Programming(MPQP) and online computation processes for explicit model predictive control and controller design fora 3-DOF helicopter are discussed. The controller design for set-point regulation and tracking time-varying referencesignals of a 3-DOF helicopter are presented respectively. Numerical study of explicit model predictive controlfor attitude regulation and tracking of a 3-DOF helicopter are conducted. A hardware-in-the-loop experimentalstudy of explicit model predictive control of a 3-DOF helicopter is made. To analyze the performances of an EMPCcontrolled helicopter system, an Active Mass Disturbance System and manual interference are considered in comparisonwith PID scheme. Numerical simulation and HIL experimental studies show that explicit model predictivecontrol is valid and has satisfactory performance for a 3-DOF helicopter.

Effect of ultrahigh pressure processing (UHP) on physicochemical properties, antioxidant activity and anti-inflammatory activity of insoluble dietary fiber from Pholiota nameko

Haiping Li,Xinqi Guo,Xun Zhu,Yina Chen,Limin Zhang,Jiaqi Lu,Qiuting Qian 한국식품과학회 2024 Food Science and Biotechnology Vol.33 No.2

The aim of this study was to evaluate the effect of ultrahigh pressure processing (UHP) of 200, 300, 400, 500, 600 and 700 MPa for 20, 40 and 30 min on physicochemical and bioactive properties of the insoluble dietary fiber Pholiota nameko (PN-IDF). The results revealed that UHP were capable of decreasing the particle size of PN-IDF and binding phenolic content. Moreover, UHP technique had an improving effect on the bioaccessible phenolic content, the water-holding capacity, the oil-holding capacity and the nitrite ion adsorption capacity. Further, UHP technique presented a promoting effect on the antioxidant activity by scavenging ABTS or DPPH free radicals and increasing reducing power, and the anti-inflammatory activity by inhibiting carrageenan-induced paw edema on PN-IDF. Overall, this study well proved that UHP technology could improve the physicochemical and functional quality of PN-IDF, which could be used as a promising green technique for functional food ingredients processing.

Experimental Study on the Mechanism of Intermittent Water and Mud Inrush Caused by Dredging and Rainfall considering Sedimentary Characteristics in Karst Tunnels

Xin Huang,Tong Wang,Zhenhao Xu,Zhengguo Zhu,Jiaqi Guo,Peng Lin,Yongchao Tian 대한토목학회 2023 KSCE Journal of Civil Engineering Vol.27 No.5

The mechanism of intermittent water and mud inrush is a difficult problem faced by disaster prevention and safe construction in karst tunnels. Aiming at revealing the mechanism of intermittent water and mud inrush, we developed an integrated testing system for filling medium deposition in karst caves and intermittent water and mud inrush. By conducting a serial of laboratory experiments, we analyzed the sedimentary characteristics of the filling medium in karst caves and the catastrophic process of intermittent water and mud inrush induced by dredging and rainfall under realistic sedimentary conditions. The results show that the filling medium exhibits layered deposition characteristics, which are affected by the water circulation time, the amount of sediments carried by water and the water flow rate. The first inrush incubation time reduces with the water head increases. The critical water head and the disaster incubation time increase with the deposition height increases. Under the same conditions, the first inrush incubation time of gravel type, silt type, and clay type filling medium decrease sequentially. The results can provide a theoretical basis for preventing intermittent water and mud inrush disasters in karst tunnels.