Suboptimal Relational Tree Configuration and Robust Control Based on the Leader-follower Model for Self-organizing Systems Without GPS Support

Zhi-gang Xiong,Ya-Song Luo,Zhong Liu,Zhi-kun Liu 제어·로봇·시스템학회 2024 International Journal of Control, Automation, and Vol.22 No.4

This paper surveys the formation acquisition and maintenance of multi-agent systems, while the communication graph is obtained without human designations. Given that all agents move along unpredictable paths during formation acquisition, the systems adopt the leader-follower model. For better expression of the graph construction, a relational tree is introduced to describe the follower-leader pairs. Then, a distributed method is proposed for suboptimal relational tree configuration. By utilizing particle swarm optimization (PSO), the search for follower-leader pairs is converted to permutation optimization. Based on principal component analysis (PCA), the entire group is divided into several small groups, and the optimization can be implemented in each group, thus releasing the computation burden. To acquire the formation defined by the suboptimal relational tree, a second nonlinear controller subject to the loss of GPS information is established. The controller takes the reference in the local velocity frame as inputs, and proportional and differential components are introduced to provide a soft control. In addition, adaptive parameters are designed for robust control. By tuning the parameters autonomously, self-organized systems can work well in various scenarios even without manual adjustment of parameters. Mathematical and numerical analyses are conducted to prove the feasibility of the proposed strategy.

Sequences Feature Vectors Extracting Method for Similarity Measurement Based on Wavelet and Matrix Transforming

Zhi-kun Hu,Wei-hua Gui,Chun-hua Yang,Fei Xu 제어·로봇·시스템학회 2010 International Journal of Control, Automation, and Vol.8 No.2

A feature vectors extracting method for similarity measurement between a referenced sequence and an analyzed sequence is proposed. The referenced sequence and analyzed sequence are compressed into two wavelet matrices by Discrete Orthogonal Wavelet Transform (DOWT), respectively. A singular value vector and the multi-subspaces of the referenced matrix are derived from wavelet matrices by singular value decomposition (SVD). Consequently, a uniform subspace of which all sequences are mutual orthogonal can be constructed by serializing multi-subspaces, and the analyzed feature vectors can also be obtained by inner product transformation between analyzed sequence and all sequences derived from the multi-subspaces. The similarity is measured between the analyzed feature vector and the singular value vector of the referenced sequence. The simulation results show that the proposed method is improved in the dimension, accuracy and anti-noise ability with little sensitivity sacrifice.

Analysis and Correction of Through-bolt End-region Overheating and Breakdown Failure in a Large Tubular Hydro-generator

Zhi-ting Zhou,Zhen-nan Fan,Jian-fu Li,Kun Wen,Bide Zhang,Tao Wang,Yan-kun Xia,Zhang Sun,Bing Yao 대한전기학회 2018 Journal of Electrical Engineering & Technology Vol.13 No.6

A field-circuit coupling model of a typical faulty generator is established to correct through-bolt end-region overheating and breakdown failure in a tubular hydro-generator. Using the model, eddy current loss and electromagnetic forces on through bolts under normal and failure conditions are analyzed and compared and the natural frequency of a through bolt is determined. Based on the analysis results, the causative mechanism of failure is revealed and targeted improvement design measures are proposed. The numerical results are found to be consistent with the actual fault characteristics, validating the design measure improvements. The results are useful in improving the design and manufacturing standards and enhancing the operational reliability of large tubular hydrogenerators.

Fault Classification Method for Inverter Based on Hybrid Support Vector Machines and Wavelet Analysis

Zhi-kun Hu,Wei-hua Gui,Chun-hua Yang,Peng-cheng Deng,Steven X. Ding 제어·로봇·시스템학회 2011 International Journal of Control, Automation, and Vol.9 No.4

A new classification method for fault waveform is proposed based on discrete orthogonal wavelet transform (DOWT) and hybrid support vector machine (hybrid SVM) for fault type of a three-phase voltage inverter. The waveforms of output voltage obtained from the faulty inverter are decomposed by DOWT into wavelet coefficient matrices, through which we can obtain singular value vectors acted as features of time-series periodic waveforms. And then a multi-classes classification method based on a new Huffman Tree structure is presented to realize 1-v-r SVM strategy. The extracted features are applied to hybrid SVM for determining fault type. Compared to employing the structure based on ordinary binary tree, the superiority of the proposed SVM method is shown in the success of fault diagnosis because the average Loo-correctness of the SVM based on Huffman tree structure exceed the general SVM 3.65%, and the correctness reaches 99.6%.

An Efficient Multi-PCA Based On-line Monitoring Scheme for Multi-Stages Imperial Smelting Process

Zhi-kun Hu,Zhi-wen Chen,Wei-Hua Gui,Chun-hua Yang,Lin-zi Yin,Xiao-qi Peng 제어·로봇·시스템학회 2013 International Journal of Control, Automation, and Vol.11 No.2

Imperial Smelting Process (ISP) is one of the main methods for Zinc and Lead smelting. In this paper, we firstly focus on its unique characteristics that ISP consists of many feeding cycles repeated in a similar way, and the normal process changes and multiple operating conditions would be frequently found in the process which would always lead to false alarms. To this end, we classify each feeding cycles of ISP into initial stage, transition stage, and steady stage, and use standard PCA, first order perturbation (FOP) based recursive dynamic PCA and multi-mode approach to deal with them respectively. The monitoring results using real data show that the proposed scheme can be able to eliminate false alarms and detect faults efficiently.

Colorimetric Probe Coupled to Dispersive Liquid–Liquid Microextraction for Determination of Dopamine in Serum

Zhi-gang Tai,Yi-ren Zhu,Yi-bo Yuan,Jin Liu,Zhen-jie Li,Zhi-hua Liu,Kun-miao Wang 대한화학회 2020 Bulletin of the Korean Chemical Society Vol.41 No.3

In this work, a highly sensitive method using a colorimetric probe coupled to dispersive liquid?liquid microextraction (DLLME) was developed for the quantitative determination of dopamine (DA) in serum. The DA in serum was concentrated by DLLME to increase the detection sensitivity and reduce the matrix effects. After the DLLME process, a colorimetric probe of silver triangular nanoparticles (AgTNPs) was used to detect DA, which was based on the plasma transformation of AgTNPs caused by strong interactions with melamine (MA). The results showed that DA could inhibit the aggregation of AgTNPs induced by MA, resulting in the recovery of the surface plasmon resonance (SPR) peak of AgTNPs. Thus, the DLLME method followed by colorimetric probe detection of DA can be achieved. The parameters affecting the proposed method were optimized, under the optimal conditions, a linear calibration curve was obtained over a concentration range of 5 to 250?nM with a recovery from 94.4 to 101.3%. The detection limit was 1.6 nM (at an S/N ratio of 3). The present method was successfully applied to determine DA in human serum.

Random vibration analysis of train-slab track-bridge coupling system under earthquakes

Zhi-ping Zeng,Xian-feng He,Yan-gang Zhao,Zhi-wu Yu,Ling-kun Chen,Wen-tao Xu,Ping Lou 국제구조공학회 2015 Structural Engineering and Mechanics, An Int'l Jou Vol.54 No.5

This study aimed to investigate the random vibration characteristic of train-slab track-bridge interaction system subjected to both track irregularities and earthquakes by use of pseudo-excitation method (PEM). Each vehicle subsystem was modeled by multibody dynamics. A three-dimensional rail-slabgirder-pier finite element model was created to simulate slab track and bridge subsystem. The equations of motion for the entire system were established based on the constraint condition of no jump between wheel and rail. The random load vectors of equations of motion were formulated by transforming track irregularities and seismic accelerations into a series of deterministic pseudo-excitations according to their respective power spectral density (PSD) functions by means of PEM. The time-dependent PSDs of random vibration responses of the system were obtained by step-by-step integration method, and the corresponding extreme values were estimated based on the first-passage failure criterion. As a case study, an ICE3 high-speed train passing a fifteen-span simply supported girder bridge simultaneously excited by track irregularities and earthquakes is presented. The evaluated extreme values and the PSD characteristic of the random vibration responses of bridge and train are analyzed, and the influences of train speed and track irregularities (without earthquakes) on the random vibration characteristic of bridge and train are discussed.

Identification and characterization of BGL11(t), a novel gene regulating leaf-color mutation in rice (Oryza sativa L.)

Zhi-kun Wang,Yun-xiang Huang,Zheng-diao Miao,Zhi-yan Hu,Xin-zhang Song,Li Liu 한국유전학회 2013 Genes & Genomics Vol.35 No.4

A novel bright-green leaf mutant, bgl11, derived from Nipponbare (Oryza sativa L. ssp. japonica) treated by ethyl methanesulfonate (EMS), exhibited a distinct brightgreen leaf phenotype throughout development. Chlorophyll contents of bgl11 decreased significantly than that of its wild-type parent. Genetic analysis suggested that the brightgreen leaf trait was controlled by a single recessive nuclear gene, which was tentatively designed as BGL11(t). To isolate the BGL11(t) gene, a map-based cloning strategy was employed, and the gene was finally mapped in a 94.7 kb region between marker InDel11-5 and InDel11-9 on the long arm of chromosome 11, in which no gene leaded to leaf-color mutation had been mapped or cloned. Cloning and sequencing analysis revealed that, LOC_Os11g38040, which was predicted to encode an expressed protein, had a 9 bp segment deletion in the coding region of bgl11. Furthermore, the transgenic plants with wild-type gene LOC_Os11g38040were restored to normal phenotype. Accordingly, the gene (LOC_Os11g38040) was identified as the BGL11(t) gene. These results are very valuable for further study on BGL11(t)gene and illuminating the mechanism of chloroplast development in rice.

Analysis and Correction of Through-bolt End-region Overheating and Breakdown Failure in a Large Tubular Hydro-generator

Zhou, Zhi-ting,Fan, Zhen-nan,Li, Jian-fu,Wen, Kun,Zhang, Bide,Wang, Tao,Xia, Yan-kun,Sun, Zhang,Yao, Bing The Korean Institute of Electrical Engineers 2018 Journal of Electrical Engineering & Technology Vol.13 No.6

A field-circuit coupling model of a typical faulty generator is established to correct through-bolt end-region overheating and breakdown failure in a tubular hydro-generator. Using the model, eddy current loss and electromagnetic forces on through bolts under normal and failure conditions are analyzed and compared and the natural frequency of a through bolt is determined. Based on the analysis results, the causative mechanism of failure is revealed and targeted improvement design measures are proposed. The numerical results are found to be consistent with the actual fault characteristics, validating the design measure improvements. The results are useful in improving the design and manufacturing standards and enhancing the operational reliability of large tubular hydro-generators.

Design of Coordination-Crosslinked Nitrile Rubber with Self-Healing and Reprocessing Ability

Zhi Fei Zhang,Xue Tong Liu,Kun Yang,Shu Gao Zhao 한국고분자학회 2019 Macromolecular Research Vol.27 No.8

In this work, we describe a simple approach to design of a coordination crosslinked elastomer with extraordinary mechanical properties: self-healing and recycling abilities by introducing Co-cyano coordination into nitrile rubber(NBR) matrix. The formation of reversible coordination crosslink network results in good mechanical properties superior to conventional sulfur-cured NBR, such as high stretchability and toughness. The reversibility of metal-ligand bond endows the polymer with self-healing capability and recycling or reprocessing abilities by rearrangement at elevated temperature. The fully cut samples after self-healing or reprocessing can restore their original tensile strength. It is also worth noting that the reclaimed NBR exhibited higher modulus than its original sample due to the compensation of new metal-ligand bonds formed during heating. This study provides possibilities to extend lifetime, reshaping and recycling capabilities of commercial rubber and reduce toxicity and environmental issues caused by waste rubber.