Recognition Algorithm and Optimization Experiments on Tomato Picking Robots

Xifeng Liang,Zhengshuai Jiang,Binrui Wang 보안공학연구지원센터 2016 International Journal of Signal Processing, Image Vol.9 No.9

In order to improve the recognition accuracy of vision system on tomato picking robots, the paper proposed a method of feature extraction and recognition for ripe tomato based on illumination irrelevant images and support vector machine (SVM). In this method, we adopted vector median filter (VMF) to process the tomato images to eliminate noise and make the images more smooth firstly. To avoid the effects of natural environment illumination to the vision system, we processed tomato images and obtained the tomato illumination irrelevant images according to color constancy algorithm of the single pixel. Secondly, we segmented illumination irrelevant images using OSTU method, separated multiple objects by a watershed algorithm based on distance transform and got the target area with mathematical morphology. Also we extracted color, shape and textural features of the ripe tomatoes. Finally, we did experiments on recognizing tomatoes using support vector machine (SVM) with different kernel functions. At the same time, in order to obtain optimal model of SVM, we adopted cross validation and grid search method to optimize the model parameters. The experiment results show that illumination irrelevant processing not only can eliminate the influence of light intensity, but save a gray transferring step for further image segmentation. SVM with radial basis function is better than other kernel functions SVM and the tomato recognition accuracy is 95.7%. Through optimizing the parameter C and r of radial basis function, the tomato recognition accuracy reaches up to 96.9% with the increase of 1.2% when C and r is 4 and 16 respectively. This proves that it's feasible and effective to optimize SVM's parameters by cross validation and grid search method, which provide foundation for further research on vision system of tomato picking robots.

Optimization of a crossbar parallel machine tool based on workspace and dexterity

Fang Xifeng,Zhang Sichong,Xu Qinhuan,Wang Tongyue,Liu Yuanwei,Chen Xiaogang 대한기계학회 2015 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.29 No.8

Increasing workspace and improving dexterity are important tasks for the design of parallel machine tools. The workspace of a crossbarparallel machine tool with constraints is obtained by using a 3D search method based on inverse kinematics. The new Jacobian matrixof the machine is also derived by using the natural coordinate method. Dexterity distribution of the machine tool is obtained on the basisof the workspace and the new Jacobian matrix. Influences of the structural parameters on the workspace volume index (WVI) and globaldexterity index (GDI) are analyzed. Structural optimization is conducted by treating the WVI and GDI as the global optimization goals. Unlike the initial data, the optimized results increased by 0.43 and 0.34 times.

Three New Loci of Insertion Element IS1112 in Chinese Strains of Xanthomonas oryzae pv. Oryzae

Jiajian Xie,Xifeng Wang,Feiwu Li,Yufa Peng,Guanghe Zhou 한국미생물학회 2007 The journal of microbiology Vol.45 No.3

Insertion sequence IS1112 is a repetitive element with a relatively high number of copies in Xanthomonas oryzae pv. oryzae (Xoo), the causal agent of bacterial blight of rice (Oryza sativa L.). Three new loci of IS1112 were identified in seven Chinese strains of Xoo using a single oligonucleotide primer J3; 5'-GCTCAGGTCAGGTGGCCTGG-3’by insertion-sequence-based polymerase chain reaction (IS-PCR). Among the three new loci of IS1112, two were located in the open-reading frame region of genes fhuA and cirA, which encode TonB-dependent receptors, and the third in ISXo2, another type of insertion sequence in Xoo genome. Three variants of IS1112 were identified in those three loci based on their sequence similarities: two were identical to IS1112a and IS1112b, reported in strain PXO86 from the Philippines, while the third was a new member of IS1112, defined as IS1112d. Inserting IS1112 in gene fhuA caused three bases, GGT, to be duplicated at the target site, but inserting it in gene cirA did not cause any duplication in the target site. The diversity of IS1112 sequence and insertion loci in Xoo genome and their potential effects are discussed.

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.

Three New Loci of Insertion Element IS1112 in Chinese Strains of Xanthomonas oryzae pv. oryzae

Xie, Jiajian,Wang, Xifeng,Li, Feiwu,Peng, Yufa,Zhou, Guanghe The Microbiological Society of Korea 2007 The journal of microbiology Vol.45 No.3

Insertion sequence IS1112 is a repetitive element with a relatively high number of copies in Xanthomonas oryzae pv. oryzae (Xoo), the causal agent of bacterial blight of rice (Oryza sativa L.). Three new loci of IS1112 were identified in seven Chinese strains of Xoo using a single oligonucleotide primer J3; 5'-GCTCA GGTCAGGTGGCCTGG-3' by insertion-sequence-based polymerase chain reaction (IS-PCR). Among the three new loci of IS1112, two were located in the open-reading frame region of genes fhuA and cirA, which encode TonB-dependent receptors, and the third in ISXo2, another type of insertion sequence in Xoo genome. Three variants of IS1112 were identified in those three loci based on their sequence similarities: two were identical to IS1112a and IS1112b, reported in strain PXO86 from the Philippines, while the third was a new member of IS1112, defined as IS1112d. Inserting IS1112 in gene fhuA caused three bases, GGT, to be duplicated at the target site, but inserting it in gene cirA did not cause any duplication in the target site. The diversity of IS1112 sequence and insertion loci in Xoo genome and their potential effects are discussed.

MODELING AND CONTROL OF A HIGH SPEED ON/OFF VALVE ACTUATOR

Jigen Fang,Xifeng Wang,Jinjun Wu,Shuai Yang,Liang Li,Xiang Gao,Yue Tian 한국자동차공학회 2019 International journal of automotive technology Vol.20 No.6

Accurate electromagnetic force control in a high speed on/off valve actuator (HSVA) can improve the performance of a vehicle braking system, and an accurate theoretical model is the key to smoothly controlling the high speed on/off valve. Therefore, a nonlinear model of an HSVA is proposed in this paper. Three subsystems are modeled as a spring/ mass/damper system, a nonlinear resistor/inductor system and a multiwall heat transfer system, respectively. Then, a slidingmodel controller combined with a sliding-model observer is designed to adjust the electromagnetic force for an accurate HSVA state control, taking the effect of the coil heating into account. The feasibility of the three submodels and the slidingmodel controller are verified by comparing the simulation results with the experimental results obtained on a test bench. Our study shows that the three subsystems are coupled to one another through resistance, displacement, and temperature. When the excitation voltage exceeds 9 V, the coil temperature can reach more than 150 degrees Celsius within 300 s, and the electromagnetic force decreases by approximately 30 %. However, by applying the above control strategy, the electromagnetic force can also be stable, fluctuating within 5 % even if the temperature of the coil rises to the thermal equilibrium temperature.

Expression profiling of the mitogen-activated protein kinase gene family reveals their diverse response pattern in two different salt-tolerant Glycyrrhiza species

Cao Aiping,Gao Ling,Wang Fei,Tong Xuechen,Xie Shuangquan,Chen Xifeng,Lu Tianxin,Shen Haitao,Liu Hailiang,Jin Xiang,Li Hongbin 한국유전학회 2022 Genes & Genomics Vol.44 No.7

Background: Mitogen-activated protein kinases (MPKs) play important role in response to environmental stress as crucial signal receptors or sensors. Our previous study indicated that salt stress acts as a positive factor to stimulate the production of pharmacodynamic metabolites in the medicinal plant Glycyrrhiza uralensis. Currently, little is known about the MPK gene family and their functions in the medicinal plant G. uralensis. Objective: Identification, comprehensive bioinformatic analysis, expression profiling, and response pattern under salt stress of the G. uralensis GuMPK gene family. Methods: Genome-wide investigation and expression profiling of the MPK gene family in G. uralensis, and their phylogenetic relationships, evolutionary characteristics, gene structure, motif distribution, promoter cis-acting element, and expression pattern under salt stress in two different salt-tolerant Glycyrrhiza species were performed. Results: A total of 20 G. uralensis GuMPK genes were identified and categorized into five groups, and had conserved gene structure and motif distribution. Expression profiling of GuMPK genes suggested their potentially diverse functions in plant growth and in response to phytohormones and environmental stress, particularly GuMPK1, 2, 5, and 10 as key components for G. uralensis in response to abiotic stress. Further expression analysis under NaCl treatment in two different salt-tolerant Glycyrrhiza species displayed the MPKs' different response patterns, emphasizing the role of MPK2, 5, 7, and 16 as potentially crucial genes for Glycyrrhiza to respond to salt stress. Conclusion: Our results provide a genome-wide identification and expression profiling of MPK gene family in G. uralensis, and establish the foundation for screening key responsive genes and understanding the potential function and regulatory mechanism of GuMPKs in salt responsiveness.

Cube Theory and k-error Linear Complexity Profile

Jianqin Zhou,Wanquan Liu,Xifeng Wang 보안공학연구지원센터 2016 International Journal of Security and Its Applicat Vol.10 No.7

The linear complexity and k-error linear complexity of a sequence have been used as important measures for keystream strength. In order to study k-error linear complexity of binary sequences with period 2n, a new tool called cube theory is developed. In this paper, we first give a general decomposition approach to decompose a binary sequence with period 2n into some disjoint cubes. Second, a counting formula for m-cubes with the same linear complexity is derived, which is equivalent to the counting formula for k-error vectors. The counting formula of 2n-periodic binary sequences which can be decomposed into more than one cube is also investigated, which extends an important result by Etzion et al.. Finally, we study 2n-periodic binary sequences with the given k-error linear complexity profile. Consequently, the complete counting formula of 2n-periodic binary sequences with given k-error linear complexity profile of descent points 2, 4 and 6 is derived. The periodic sequences having the prescribed k-error linear complexity profile with descent points 1, 3, 5 and 7 are also briefly discussed.

Molecular Characteristics and Potent Immunomodulatory Activity of Fasciola hepatica Cystatin

Kai Zhang,Yucheng Liu,Guowu Zhang,Xifeng Wang,Zhiyuan Li,Yunxia Shang,Chengcheng Ning,Chunhui Ji,Xuepeng Cai,Xianzhu Xia,Jun Qiao,Qingling Meng 대한기생충학ㆍ열대의학회 2022 The Korean Journal of Parasitology Vol.60 No.2

Cystatin, a cysteine protease inhibitor found in many parasites, plays important roles in immune evasion. This study analyzed the molecular characteristics of a cystatin from Fasciola hepatica (FhCystatin) and expressed recombinant FhCystatin (rFhcystatin) to investigate the immune modulatory effects on lipopolysaccharide-induced proliferation, migration, cytokine secretion, nitric oxide (NO) production, and apoptosis in mouse macrophages. The FhCystatin gene encoded 116 amino acids and contained a conserved cystatin-like domain. rFhCystatin significantly inhibited the activity of cathepsin B. rFhCystatin bound to the surface of mouse RAW264.7 cells, significantly inhibited cell proliferation and promoted apoptosis. Moreover, rFhCystatin inhibited the expression of cellular nitric oxide, interleukin-6, and tumor necrosis factor-α, and promoted the expression of transforming growth factor-β and interleukin-10. These results showed that FhCystatin played an important role in regulating the activity of mouse macrophages. Our findings provide new insights into mechanisms underlying the immune evasion and contribute to the exploration of potential targets for the development of new drug to control F. hepatica infection.

Investigation of bipolar matrix based mixed host in highly efficient green delayed fluorescence organic light-emitting diodes

Zheng Yanqiong,Peng Junbiao,Tang Jie,Li Weiguang,Chen Juncong,Wang Chao,Zhang Jianhua,Wei Bin,Li Xifeng 한국물리학회 2021 Current Applied Physics Vol.22 No.-

The mixed cohosts of electron transport host (E-host): 4,40-bis(carbazol-9-yl)biphenyl (CBP) have been comparatively investigated for an efficient green fluorescent organic light emitting diode (OLED) doped with a thermally activated delayed fluorescence (TADF) emitter (4s,6s)-2,4,5,6-tetra(9H-carbazol-9-yl)isophthalonitrile (4CzIPN). The E-host:CBP systems significantly enhance the electroluminescent (EL) properties. After doping Ehost, the lifetime of the emissive layer decreases and the surface becomes smoother, together with the impedance decreases for one magnitude and the hole-injection depresses. The charge balance and improved interface both contribute to the EL performance enhancement. Here we develop a universal mixed host system suitable to most of emitters.