An Improved Strong Tracking UKF Based on Fading Factor

Jian Feng,Xiao-dong Su,Yu-ru Zhang,Hai-tao Jiang,Jun-ling Li 보안공학연구지원센터 2014 International Journal of Hybrid Information Techno Vol.7 No.4

Design and Implementation of Embedded Serial Communication Based on Finite State Machine

Jian Feng,Yuanyuan Ding 보안공학연구지원센터 2015 International Journal of Hybrid Information Techno Vol.8 No.9

In order to solve problems of poor real-time capability, poor reliability and low fault tolerance for data transmission in embedded serial communication, a serial communication protocol based on finite state machine (FSM) was designed and implemented, and was applied in communications of network management. The packet format and the communication control mechanism of the serial communication protocol are described, and complete framework for the application is given. Process of receiving and transmitting FSM models in serial communication are abstracted, combined with the interrupt service routine. In practical application, the serial communication program can meet the functional and performance requirements of serial communication between embedded devices and network management system (NMS).

Failure Analyses of a Reinforced Embankment by Strength Reduction and Limit Equilibrium Methods Considering Hardening of Soft Clay

Jianfeng Chen,Junxiu Liu,Jianfeng Xue,Zhenming Shi 대한토목학회 2014 KSCE JOURNAL OF CIVIL ENGINEERING Vol.18 No.7

A 7.6 m high reinforced embankment-wall system was constructed in stages on very thick soft clay. The reinforced structure incurred a deep-seated global failure at the end of backfill loading. The Strength Reduction Method (SRM) and the Limit Equilibrium Method (LEM) were employed to analyze the stability of the structure. It was found that the SRM captured the deep-seated global failure of the structure through a coupled mechanical and hydraulic Finite Element (FE) modeling. The stability of the reinforced structure was much underestimated or overestimated by the LEM using unconsolidated-undrained or consolidated-undrained shear strength values. However, the stability of the structure could be still captured by the LEM with the increased shear strength values assigned to the consolidated zone directly beneath the reinforced structure and with the unconsolidated-undrained shear strength values assigned to the unconsolidated zone beyond the structure. In practice, both the SRM and the LEM are recommended for stability analyses of geosynthetic-reinforced structures on soft ground considering hardening of the soil so that the results from the two methods can be cross-examined.

Experimental Measurement and Numerical Computation of Geogrid Tension in Centrifuge Modeling

Jianfeng Chen,Songbo Yu,Jianfeng Xue,Zhenming Shi 대한토목학회 2011 KSCE JOURNAL OF CIVIL ENGINEERING Vol.15 No.8

Tension measurement of geogrid is essential in reinforcement mechanisms studies. Geogrid is a nonlinear flexible material with large apertures, it is difficult to measure the tensions mobilized in geogrid, especially in scaled-down geogrid in centrifuge modeling. In this study, strain gauges were glued onto the surface of model geogrid with epoxy resin and were calibrated through multi-stage and continuous tensile tests. Generalized Kelvin model was used to fit the constitutive curves from the tensile tests. The model is capable to describe time-dependent and nonlinear behavior of the composite material of epoxy resin and model geogrid. Based on generalized Kelvin model, tensions in the model geogrid were measured in a centrifugal modeling of a reinforced embankment on soft clay. A finite element model was developed to simulate the centrifuge modeling and a comparison was carried out between the computed and measured tensions. The numerical results basically captured the measured reinforcements, indicating that the method of reinforcement measurement proposed in this study is appropriate and reasonable.

Enhanced Sliding Mode Control and Online Estimation of Optimal Slip Ratio for Railway Vehicle Braking Systems

Jianfeng Liu,Qing Peng,Zhiwu Huang,Weirong Liu,Heng Li 한국정밀공학회 2018 International Journal of Precision Engineering and Vol.19 No.5

This paper proposes an optimal anti-locking control scheme so as to improve the braking performance of railway vehicles. The controlling effect of sliding mode control is improved, and the optimal slip ratio is achieved by extreme seeking algorithm. Firstly, a substitute function for the conventional sign function is proposed. Secondly, a closed loop observer for braking systems is used to enhance the estimation value of adhesion force, which can also be used for calculating reference speed. Finally Sliding Mode Controlbased controller needs to be entered a reference slip ratio called optimal slip ratio, which is searched by extreme seeking algorithm from the functional relationship between slip ratio and friction coefficient. Thus, the maximum adhesion is achieved despite wheel/ rail surface changes. The simulation result demonstrates the effect of real-time adjustment for braking torque, which guarantees the braking performance.

Optimization and Control of Cable Tensions for Hyper-redundant Snake-arm Robots

Jianfeng Tao,Chengjin Qin,Zhilin Xiong,Xiang Gao,Chengliang Liu 제어·로봇·시스템학회 2021 International Journal of Control, Automation, and Vol.19 No.11

Based on the feedback linearization of joints motion and the tension optimization of cables, a hyperredundant snake-arm robot control strategy is presented to solve the problems caused by the joint motion coupling and the cable drive redundancy. First, a hierarchical control system architecture of snake-arm robot is developed. Subsequently, the computed torque control method is utilized to decouple the motion in the joint space, and the tension distribution satisfying the constraint condition is obtained in the cable space by quadratic programming. Since it is hard and also expensive to feedback joint motion and cable tension by sensors, the cable tensions are obtained by the system dynamics equation and the position and speed of joints motion is calculated approximately from the driving electric motors’ position. Finally, the control performance under three typical conditions is studied by numerical simulation. The results demonstrate that the presented method can effectively limit the cable tensions within the range of the minimum preload tension and the maximum allowable tension.

WSN Missing Data Imputing Based on Multiple Time Granularity

Jianfeng Xu,Yu Li,Yuanjian Zhang,Azhar Mahmood 보안공학연구지원센터 2016 International Journal of Future Generation Communi Vol.9 No.6

Missing data is a common phenomenon in the data collection process of wireless sensor network (WSN), and the missing data imputing is an important issue of WSN stream data mining. Currently WSN missing data imputing method has little considered about the dynamic characteristics of internal data time structure during the data collection process, which makes data imputing difficult to reflect the real monitoring change objectively. In order to analyze the internal structure and dynamics of WSN time sequence data systematically, with the equivalence relation of the monitored object the time domain can be regarded as a series of integral time granule (ie atomic time point set), a wireless sensor network timing information system (WTIS) is established. The system can reason logically at different time granularity, and a multiple optimal time granularity strategy of WTIS based on hierarchical successive approximation approach is proposed. Finally, based on the research, a multiple optimal time granularity WSN missing data clustering imputing algorithm is proposed. Compared with traditional fixed time granularity missing data imputing algorithm, experiments show that the algorithm can lower error rate when imputing WSN missing data.

Fusion Detection Algorithm for Infrared Dim Target based on Temporal-Spatial Domain Accumulation and Difference

Jianfeng Wu,Shucai Huang,Hongxia Kang,Yu Zhong 보안공학연구지원센터 2015 International Journal of Signal Processing, Image Vol.8 No.11

Aiming at the problem of the dim target real-time detection in Infrared search and track (IRST) systems, a fusion detection algorithm for infrared dim target based on temporal-spatial domain accumulation and difference is proposed. The proposed algorithm suppresses background and enhances targets by template filtering and difference processing in space domain, and the image sequences are processed by multi-frame energy accumulation and frame difference methods according to the target’s moving characteristics in time domain. After the fusion segmentation of the temporal and spatial processing results with definite rule, the target can be detected by the relation of the possible target’s position in adjoining frames according to target’s moving continuity and regularity. Experimental results show that the proposed algorithm enormously increases the target's SNR after the temporal-spatial fusion enhancement, and it has high detection probability and high detecting speed. In the meantime, the algorithm is easy to realize in hardware and can be applied effectively in the real-time target detection of the IRST systems.

Numerical investigation on the dynamic behaviors of turbine valve disc–seat impact at low velocity

Jianfeng Mao,Wei Zhe Wang,Junhui Zhang,Ying Zheng Liu 대한기계학회 2015 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.29 No.2

In this study, the dynamic behaviors on a valve seat subjected to the impact of the valve disc at low velocities were investigated by usingnumerical analysis with finite element method. The impact damage of the valve disc against seat was evaluated through a threedimensionaldynamic explicit calculation. The parameters considered in the simulations were impact velocity, disc obliquity, aspect ratio,and contact area ratio. The model for impact calculation was implemented in the code ABAQUS, which is based on the constitutiveequation and fracture strain equation of Johnson and Cook, as well as on continuum damage mechanics. The distribution of damagecaused by the impact was computed and discussed. The impact damage of the valve disc was minimized when the disc obliquity wasapproximately 40°. The effects of variation of selected design parameters on dynamic behaviors were discussed. The best design parameterswere proposed, which served as a guide for future valve design.

AN ECONOMIC ANALYSIS OF HOUSEHOLD INCOME INEQUALITY AND BMI IN CHINA

JIANFENG YAO,FAFANYO ASISEH 중앙대학교 경제연구소 2019 Journal of Economic Development Vol.44 No.1

This paper explores the relationship between household income inequality at county level and Body Mass Index (BMI). The hypotheses associating BMI with income inequality are tested. Unlike most literature that found positive linear relationship between prevalence of overweight or obesity and household income inequality, by using a longitudinal data from China Health and Nutrition Survey (CHNS) between 1991 and 2011, we find that BMI will first decrease with household income inequality and then increase at an increasing rate, which suggests that high inequality may speed up the possibility of being overweight and obese. Policy measures on controlling obesity should be directed towards reducing inequality.