Sparse decision feedback equalization for underwater acoustic channel based on minimum symbol error rate

Wang Zhenzhong,Chen Fangjiong,Yu Hua,Shan Zhilong 대한조선학회 2021 International Journal of Naval Architecture and Oc Vol.13 No.1

Underwater Acoustic Channels (UAC) have inherent sparse characteristics. The traditional adaptive equalization techniques do not utilize this feature to improve the performance. In this paper we consider the Variable Adaptive Subgradient Projection (V-ASPM) method to derive a new sparse equalization algorithm based on the Minimum Symbol Error Rate (MSER) criterion. Compared with the original MSER algorithm, our proposed scheme adds sparse matrix to the iterative formula, which can assign independent step-sizes to the equalizer taps. How to obtain such proper sparse matrix is also analyzed. On this basis, the selection scheme of the sparse matrix is obtained by combining the variable step-sizes and equalizer sparsity measure. We call the new algorithm Sparse-Control Proportional-MSER (SC-PMSER) equalizer. Finally, the proposed SC-PMSER equalizer is embedded into a turbo receiver, which perform turbo decoding, Digital Phase-Locked Loop (DPLL), time-reversal receiving and multi-reception diversity. Simulation and real-field experimental results show that the proposed algorithm has better performance in convergence speed and Bit Error Rate (BER).

Multi-scale heat conduction models with improved equivalent thermal conductivity of TRISO fuel particles for FCM fuel

Wang Mouhao,Bu Shanshan,Zhou Bing,Li Zhenzhong,Chen Deqi 한국원자력학회 2023 Nuclear Engineering and Technology Vol.55 No.3

Fully Ceramic Microencapsulated (FCM) fuel is emerging advanced fuel material for the future nuclear reactors. The fuel pellet in the FCM fuel is composed of matrix and a large number of TRistructural- ISOtopic (TRISO) fuel particles which are randomly dispersed in the SiC matrix. The minimum layer thickness in a TRISO fuel particle is on the order of 105 m, and the length of the FCM pellet is on the order of 102 m. Hence, the heat transfer in the FCM pellet is a multi-scale phenomenon. In this study, three multi-scale heat conduction models including the Multi-region Layered (ML) model, Multi-region Non-layered (MN) model and Homogeneous model for FCM pellet were constructed. In the ML model, the random distributed TRISO fuel particles and coating layers are completely built. While the TRISO fuel particles with coating layers are homogenized in the MN model and the whole fuel pellet is taken as the homogenous material in the Homogeneous model. Taking the results by the ML model as the benchmark, the abilities of the MN model and Homogenous model to predict the maximum and average temperature were discussed. It was found that the MN model and the Homogenous model greatly underestimate the temperature of TRISO fuel particles. The reason is mainly that the conventional equivalent thermal conductivity (ETC) models do not take the internal heat source into account and are not suitable for the TRISO fuel particle. Then the improved ETCs considering internal heat source were derived. With the improved ETCs, the MN model is able to capture the peak temperature as well as the average temperature at a wide range of the linear powers (165 W/ cm~ 415 W/cm) and the packing fractions (20%e50%). With the improved ETCs, the Homogenous model is better to predict the average temperature at different linear powers and packing fractions, and able to predict the peak temperature at high packing fractions (45%e50%).

Study on the Impact of Positioning Errors on the Process Performance of Robotic Bonnet Polishing

Xuepeng Huang,Zhenzhong Wang,Lucheng Li 한국정밀공학회 2023 International Journal of Precision Engineering and Vol.24 No.9

High-precision optical components are widely used in major fields such as strong lasers and astronomy, but the production cycle of components is greatly constrained by the difficulty of machining optical components and the high price of special polishing machines, so it is important to develop a high-efficiency and low-cost fast polishing system for optical components. By combining bonnet polishing technology with industrial robotics, we have developed an industrial robotics bonnet polishing system for optical components, and the effect of robot positioning errors on pad trimming and on the polishing of the entire surface is also analyzed. To verify the processing capability of the robotic bonnet polishing device, polishing pad dressing experiments and optical component surface correction polishing experiments were carried out. After the pad was dressed, the runout value was reduced from 182 to 23 μm with a convergence ratio of 7.9. After polishing the optical component twice, the PV and RMS values on the surface of the component decreased significantly, from 38.05 λ and 9.98 λ to 8.65 λ and 1.38 λ (λ = 632.8) respectively in the middle area of the component, with a convergence ratio of 4.4 and 7.2, proving that the robotic bonnet polishing system can be applied to the polishing process of optical components.

Dynamic modeling method for active magnetic bearings-rotor system of steam turbines

Chao Wu,Zhenzhong Su,Dong Wang,Hao Jiang 대한기계학회 2023 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.37 No.4

As oil-free rotor support technology, active magnetic bearings (AMBs) are increasingly applied in turbinmachinery, including steam turbines. The compact multiple disksrotor bearing system of maglev steam turbines leads to complicated dynamic behaviors, which is the basis of AMBs controllers design. In this paper, an analytical modeling method is proposed to describe the dynamic characteristics of AMBs-rotor system of maglev steam turbines. The analytic rotor dynamic model consists of multiple rigid disks on a flexible shaft and AMBs. In modeling the rotor bearing system, the flexible shaft is discretized by Euler Bernoulli beam elements. The connection between rigid disks and flexible shaft is equivalent to spring dampers. Angular stiffness and angular damping coefficients are introduced to model the spring dampers and identified by 3D finite element simulation results. The bearings force takes the control system of AMBs into consideration. Moreover, experiments of a test rig are carried out. The results show that the proposed analytical rotor dynamic modeling method is effective.

Multi-Epitope Fusion Protein Eg mefAg-1 as a Serodiagnostic Candidate for Cystic Echinococcosis in Sheep

Liu Tianli,Wang Xifeng,Tian Zhenzhong,Wang Lixia,Zhang Xingxing,Qiao Jun,Meng Qingling,Gong Shasha,Chen Ying,Cai Xuepeng 대한기생충학ㆍ열대의학회 2019 The Korean Journal of Parasitology Vol.57 No.1

Cystic echinococcosis (CE) in sheep is a hazardous zoonotic parasitic disease that is caused by Echinococcus granulosus (Eg). At present, serological test is an important diagnostic method for Eg infection in domestic animals. Here, a fusion protein Eg mefAg-1 harboring 8 dominant B-cell epitopes of Eg such as antigen B, tetraspanin 1, tetraspanin 6, reticulon and Eg95 was produced in E. coli and evaluated for CE in sheep by indirect ELISA. Eg mefAg-1 showed in ELI- SA a high sensitivity (93.41%) and specificity (99.31%), with a coincidence rate of 97.02%. Overall, it is suggested that the Eg mefAg-1 could be a potential antigen candidate for CE serodiagnosis in sheep.

Influence of relative difference between paired guide rails on motion accuracy in closed hydrostatic guideways

Chenchun Shi,Zhenzhong Wang,Yunfeng Peng 대한기계학회 2020 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.34 No.2

There have been many researches concerning the motion errors of hydrostatic guideways because they directly affect the accuracy of machined parts. Actually, each paired guide rail has its own profile feature, and the position error also cannot be zero, so the relative difference between guide rails should not be neglected. In this paper, a typical closed hydrostatic guideway with four pads is taken as the sample, and the quasi-static analysis model is directly developed by incorporating the concept of pose, which is then employed to study the effect of relative difference on motion accuracy in the field of hydrostatic guideways. The numerical results demonstrate that, the greater the amplitude deviation, the larger the motion errors, while the influence of the wavelength deviation on motion accuracy exhibits regularity only within some intervals, the phase deviation mainly affects the angular but not the linear motion error, the influence from the parallelism error is not significant. Moreover, it is figured out that the fluctuation of the difference between the average film thicknesses of two adjacent pads does result in the variation of the motion errors, the greater the fluctuation, the larger the motion errors. The revealed mechanisms are expected to be valuable for designers.

Modification of tool influence function for bonnet polishing tool based on analysis of interfacial contact state

Ri Pan,Xiangxiang Zhu,Zhenzhong Wang,Dongju Chen,Shuting Ji,Jinwei Fan,Rui Wang 대한기계학회 2022 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.36 No.6

The polishing mechanism of bonnet polishing (BP) and the tool influence function (TIF) of bonnet tool have been widely studied. However, most of current studies pay little attention to the influence of polishing slurry on the BP mechanism as well as TIF. This study proposes that the interfacial contact state between the polishing tool and the workpiece is in a mixed lubrication state, subsequently the BP mechanism is further explored. It is found that the workpiece material is removed by polishing pad and abrasives. The polishing slurry is not directly involved in workpiece removal, but shares the normal pressure of the polishing tool on workpiece, which affects material removal. Based on the above mechanism, the TIF removal prediction model is established and verified by experiments. The results show that the maximum error of the model prediction value is quiet small, which verifies the model. Moreover, compared with Preston model and the previous model, which ignored the influence of the fluid, the average prediction error of the model in this paper when D 0 = 20 mm is 6.38 %, while the previous model and Preston model are 11.21 % and 49.10 %, respectively. Which illustrates the model in this paper has higher accuracy.

Research on Automatic Compensation Technology for Eccentricity of Grinding Wheel

Shi-Ping Chen,Zhenzhong Wang,Hui Yu,Long-Qiao Lin 한국정밀공학회 2018 International Journal of Precision Engineering and Vol.19 No.8

To ensure the installation precision of grinding wheel in precision grinding, the attitude of spindle axis must be adjusted to coincide with the geometric center of grinding wheel before the process. A special device that combined with piezoelectric actuators with threedegrees- of-freedom is designed. The corresponding method of automatic compensation technology for eccentricity of grinding wheel is developed. In order to calculate accurately eccentric angle and the eccentricity of the grinding wheel, high accuracy detection algorithm for eccentric signal of grinding wheel is given by the principle of rotary roundness error minimization firstly. Then a decomposition algorithm is proposed to decompose the eccentricity into three directions and the eccentricity can be eliminated by the coordinated control of the three piezoelectric actuators. Experimental results show that the average accuracy of the system is about 5.48 μm. Compared with the sine fitting algorithm, the algorithm presented for adjusting the eccentricity of grinding wheel in this paper is more stable and the accuracy is improved by about 78.2%, which shows that the proposed approach works successfully.

Multi-type Feature Fusion Technique for Weed Identification in Cotton Fields

Guan Lin,Liu Zhenzhong,Wu Qiufeng,Wang Lulu 보안공학연구지원센터 2016 International Journal of Signal Processing, Image Vol.9 No.2

Weed identification is core of precision variable spray technology and weed information management system. Single type features are difficult to identify multi-class weeds in cotton fields. In this paper, multi-type feature fusion technique for weed identification is proposed. Firstly, multi-type features are extracted. In color feature extraction, FMS, SMS and TMS in HSI are extracted by color moment. In shape feature extraction, REC, RWL, CIR and SPH are extracted by geometric parameter method. In texture feature extraction, ASM, CON and COR are extracted by GLCM. Secondly, because feature dimension is too large, principle component analysis is used to reduce dimension to extract new features including COR, ASM, REC and two components. Finally, three comparative experiments including identification of five kinds of weeds, three kinds of weeds and two kinds of weeds are carried out. Experimental results show that method proposed in this paper is superior to state of the art and is suitable for identification of multi-class weeds. This method can also be applied in identifying weeds in other fields.

Solidification of uranium mill tailings by MBS-MICP and environmental implications

Niu Qianjin,Li Chunguang,Liu Zhenzhong,Li Yongmei,Meng Shuo,He Xinqi,Liu Xinfeng,Wang Wenji,He Meijiao,Yang Xiaolei,Liu Qi,Liu Longcheng 한국원자력학회 2022 Nuclear Engineering and Technology Vol.54 No.10

Uranium mill tailing ponds (UMTPs) are risk source of debris flow and a critical source of environmental U and Rn pollution. The technology of microbial induced calcium carbonate precipitation (MICP) has been extensively studied on reinforcement of UMTs, while little attention has been paid to the effects of MICP on U & Rn release, especially when incorporation of metakaolin and bacillus subtilis (MBS). In this study, the reinforcement and U & Rn immobilization role of MBS -MICP solidification in different grouting cycle for uranium mill tailings (UMTs) was comprehensively investigated. The results showed that under the action of about 166.7 g/L metakaolin and ~50% bacillus subtilis, the solidification cycle of MICP was shortened by 50%, the solidified bodies became brittle, and the axial stress increased by up to 7.9%, and U immobilization rates and Rn exhalation rates decrease by 12.6% and 0.8%, respectively. Therefore, the incorporation of MBS can enhance the triaxial compressive strength and improve the immobilization capacity of U and Rn of the UMTs bodies solidified during MICP, due to the reduction of pore volume and surface area, the formation of more crystals general gypsum and gismondine, as well as the enhancing of coprecipitation and encapsulation capacity