A Collision-Free Framework for Navigation of Nonholonomic Vehicle Systems

Xiaoxue Zhang,Jun Ma,Zilong Cheng,Tong Heng Lee 제어로봇시스템학회 2020 제어로봇시스템학회 국제학술대회 논문집 Vol.2020 No.10

The task of highly effective navigation is certainly one of the critical technologies of autonomous vehicles that have been widely investigated by researchers. In this paper, a navigation framework with path planning and tracking is presented, where a feasible and collision-free trajectory is generated for nonholonomic vehicle systems. In terms of path planning, an LQR-RRT<SUP>*</SUP> algorithm is applied to plan a path without collision. It is an optimal sampling-based planning algorithm with linear quadratic regulation-based heuristics, and able to tackle some rather complicated or underactuated dynamic systems. In order to improve the feasibility of the planned path and compensate for the deterioration of optimality due to sampling times, the approach is taken where a cubic spline path is additionally generated. The path tracking problem is formulated as a constrained optimization problem for the nonholonomic vehicle system, and then the required steering angle and acceleration is computed to avoid potential collisions. The results of the simulation experiments clearly demonstrate the effectiveness of the proposed navigation framework.

Integrated Planning and Control for Collision-free Trajectory Generation in 3D Environment with Obstacles

Xiaoxue Zhang,Jun Ma,Sunan Huang,Zilong Cheng,Tong Heng Lee 제어로봇시스템학회 2019 제어로봇시스템학회 국제학술대회 논문집 Vol.2019 No.10

Control of autonomous robots (ARs) is a hot topic over the past three decades, and motion planning is becoming one of the major challenges in AR control. Substantial works have been done for motion planning in 2-dimensional (2D) environments, but planning in 3D complex environments is still an open problem to be investigated. In this paper, we propose a trajectory planning method to plan a high-quality and safe trajectory in 3-dimensional (3D) environments with multiple obstacles. The proposed method is based on the integration of a global optimal 3D path planner with a local planner. First, a hierarchical path planning algorithm is used as a global path planner to compute a near-optimal path formed by a set of waypoints. Second, a local path trajectory planner is designed to track the path computed by the global path planner with multiple constraints of dynamics and environment satisfied. Finally, simulations are conducted to validate the effectiveness of the proposed trajectory generation approach subject to the constraints of robot physical limits and environmental requirements.

Application of Improved Grid Search Algorithm on SVM for Classification of Tumor Gene

Li Wenwen,Xing Xiaoxue,Liu Fu,Zhang Yu 보안공학연구지원센터 2014 International Journal of Multimedia and Ubiquitous Vol.9 No.11

According to the merits and shortcomings of the traditional gridsearch algorithm in parameters optimization of support vector machine (SVM), an improved grid search algorithm is proposed. Dichotomous search algorithm is used to reduce target searching range. First, searching range is determined roughly, and a set of parameters are obtained. Then fine search is applied in reduction the range for searching, and searching the optimum parameters.Three kinds of famous tumor gene data set are used in the comparison experiments to validate the classification accuracy of principal component analysis (PCA)-SVM and kernel principal component analysis (KPCA)-SVM. Experiment results and data analysis shows that, comparing with traditional gridsearch algorithm, the proposed method has higher classification accuracy and less search time.

The Effect of Dipping Pretreatment on Ochratoxin A Accumulation in Sultanas and Currants

Xiaoxu Zhang,Jingming Li,Dong Wang,Saisai Feng,Liyan Ma 한국식품과학회 2016 Food Science and Biotechnology Vol.25 No.3

The dipping pretreatment on the occurrence of ochratoxin A (OTA) in sultanas and currants was investigated. Grape samples were divided into two groups before a drying process. One group was dipped with potassium carbonate-ethyl oleate, and the other group was left without treatment (the control). OTA were detected using solid-phase extraction clean-up and a high-performance liquid chromatography fluorescence detector. Results showed that OTA content was below the limit of detection in the fresh grapes of both varieties. OTA were not detected in dried vine fruits before storage. However, a real naturally environmental storage revealed that the dipping pretreated samples were contaminated with OTA earlier and to a greater extent than the control. The OTA concentration in the treated and control samples after one-year storage was 0.22 and 0.19 μg/kg for sultanas and 0.34 and 0.21 μg/kg for currants, respectively. These results indicated that dipping pretreatment might increase the toxin contamination and safety risk.

Monoecism Algorithm in the Application of E-commerce Information Security

Qingjie Zhang,Jianming Zhu,Xiaoxu Wang,Yapan Li 보안공학연구지원센터 2015 International Journal of Security and Its Applicat Vol.9 No.3

With the development of e-commerce industry, the security of business information has attracted a lot of attention. The paper [1] puts forward the monoecism watermarking algorithm. The algorithm divides image into two parts: ROI (Region of interest) and RONI (Region Of Non Interest), and respectively deal with the two parts. Female watermark and male watermark are embedded into the RONI at the same time, and generate embedding watermark of the image. As is known to all, the integrity of ROI is also very important in e-commerce. This paper tries to apply the monoecism watermarking algorithm to e-commerce information security. The author gives six applications of the algorithm in electronic commerce that is graphical physical paper, electronic paper anti-counterfeiting, electronic seal, copyright protection, digital fingerprint generation, secure communication protection. This author introduced the embedding watermark and extracting watermark process and detection process of monoecism watermark algorithm. Through the analysis of simulation experiment of six application fields of monoecism watermark algorithm in the e-commerce information security, the simulation experiment has verified the validity of the algorithm. In a word, this paper has discussed the general rules of selecting ROI and the specific rules of selecting ROI in e-commerce applications. The simulation results are given, and the satisfactory results have been achieved.

Association analysis of polymorphism in the NR6A1 gene with the lumbar vertebrae number traits in sheep

Xiangyu Zhang,Cunyuan Li,Xiaoyue Li,Zhijin Liu,Wei Ni,Yang Cao,Yang Yao,Esenbay Islamov,Junchang Wei,Xiaoxu Hou,Shengwei Hu 한국유전학회 2019 Genes & Genomics Vol.41 No.10

Introduction The vertebral number is an economically significant trait, which is associated with body length and carcass traits. Nuclear Receptor Subfamily 6, Group A, Member 1 (NR6A1) is a member of the nuclear receptor superfamily and it plays an important role in the early development of embryos. Objectives The NR6A1 gene was considered as an important candidate for influence vertebrae number, while the potential associations between this gene and the number of lumbar vertebrae traits of sheep have not been explored. Methods In this study, we detected the genetic variants of NR6A1 gene and analyzed the associations of the polymorphisms with lumbar number traits in 130 Kazakh sheep. We use single-strand conformation polymorphism (SSCP) technique to detect single nucleotide polymorphism (SNP) of NR6A1 gene, and the association of the genotype and lumbar number variation was analyzed by independent Chi-square test. Results We detect SNP of NR6A1 gene by PCR-SSCP technique, and polymorphisms were only found in the coding region of exon-6 and exon-8 of NR6A1 gene. In order to investigate the connection between the SNP locus and lumbar number traits in sheep, we conducted a Chi-square test for independence for exon-6 and exon-8 of NR6A1 gene, respectively. Association analysis revealed significant associations between the SNP (rs414302710: A >C) in the exon-8 of NR6A1 gene with the number of lumbar vertebrae (P < 0.01). Conclusion Our study indicated that this SNP (rs414302710: A>C) locus of exon-8 of NR6A1 gene in sheep possible influence the number of lumbar vertebrae, which has the potential to be applied in selective breeding of sheep.

Effects of Face Sheet Structure on Mechanical Properties of 3D Integrated Woven Spacer Composites

Man Zhang,Xiaoxue Wang,Shuqiang Liu,Fu Li,Gaihong Wu 한국섬유공학회 2020 Fibers and polymers Vol.21 No.7

Due to the lightweight, structural integrity, superior heat and sound insulation performance, three-dimensional(3D) integrated woven spacer composites are expected to be used in many fields such as marine, automotive, electronics, andbuilding industries. This paper reports the effects of face sheet structure on the mechanical properties of 3D integrated wovenspacer composites. Three-point bending, quasi-static compression and low-velocity impact tests were conducted to comparethe mechanical responses of 3D woven spacer composites with plain and complex face sheets. The floating yarn segments incomplex face sheet could efficiently transfer the stress to neighboring areas and lead to a more balanced stress distribution. The existence of floats thus has positive effect on mechanical properties of composites. On the contrary, plain structuresurface was dense and the stress transfer was easily hindered by numerous weaving points, resulting in stress concentrationand ultimate premature failure. As a consequence, for surface-dominated properties such as warp-direction bending andimpact resistance, 3D integrated woven spacer composites with complex surface is better and should be given priority duringindustrial applications. In terms of weft-direction bending property and quasi-static compressive performance, which moredepend on the structure of core piles, show little difference between the composites with different surfaces.

Dynamic Trust Model Based on Extended Subjective Logic

( Tian Junfeng ),( Zhang Jiayao ),( Zhang Peipei ),( Andma Xiaoxue ) 한국인터넷정보학회 2018 KSII Transactions on Internet and Information Syst Vol.12 No.8

In Jøsang’s trust model, trust evaluation is obtained through operators, but there are problems with the mutuality and asymmetry of trust and the impact of event weight on trust evaluation. Trust evaluation is updated dynamically and continuously with time and the process of interactions, but it has not been reflected in Jøsang’s model. Therefore, final trust evaluation is not accurate, and malicious fraud cannot be prevented effectively. This causes the success rate of interaction to be low. To solve these problems, a new dynamic trust model is proposed based on extended subjective logic (DTM-ESL). In DTM-ESL, the event weight and the mutuality of trust are fully considered, the original one-way trust relationship is extended to a two-way trust relationship, discounting and consensus operators are improved, and trust renewal is designed based on event weight. The viability and effectiveness of this new model are verified by simulation experiments.

Molecular Beam Epitaxy of Highly Crystalline Monolayer Molybdenum Disulfide on Hexagonal Boron Nitride

Fu, Deyi,Zhao, Xiaoxu,Zhang, Yu-Yang,Li, Linjun,Xu, Hai,Jang, A-Rang,Yoon, Seong In,Song, Peng,Poh, Sock Mui,Ren, Tianhua,Ding, Zijing,Fu, Wei,Shin, Tae Joo,Shin, Hyeon Suk,Pantelides, Sokrates T.,Zho American Chemical Society 2017 JOURNAL OF THE AMERICAN CHEMICAL SOCIETY - Vol.139 No.27

<P>Atomically thin molybdenum disulfide (MoS2), a direct-band-gap semiconductor, is promising for applications in electronics and optoelectronics, but the scalable synthesis of highly crystalline film remains challenging. Here we report the successful epitaxial growth of a continuous, uniform, highly crystalline monolayer MoS2 film on hexagonal boron nitride (h-BN) by molecular beam epitaxy. Atomic force microscopy and electron microscopy studies reveal that MoS2 grown on h-BN primarily consists of two types of nucleation grains (0 aligned and 60 degrees antialigned domains). By adopting a high growth temperature and ultralow precursor flux, the formation of 60 degrees antialigned grains is largely suppressed. The resulting perfectly aligned grains merge seamlessly into a highly crystalline film. Large-scale monolayer MoS2 film can be grown on a 2 in. h-BN/sapphire wafer, for which surface morphology and Raman mapping confirm good spatial uniformity. Our study represents a significant step in the scalable synthesis of highly crystalline MoS2 films on atomically flat surfaces and paves the way to large-scale applications.</P>

Multiple Gene Genealogical Analyses of a Nematophagous Fungus Paecilomyces lilacinus from China

Juan Li,Heng Li,Xiaoxu Bi,Ke-Qin Zhang 한국미생물학회 2013 The journal of microbiology Vol.51 No.4

Paecilomyces lilacinus is a geographically widespread nematophagous fungus and a promising biological control agent against plant parasitic nematodes. However, relatively little is known about its patterns of genetic variation through its broad geographic and ecological contexts. In this study, we analyzed the genetic variation of 2 virulence-associated genes (PLS and PLC) and 4 housekeeping gene fragments (ITS,RPB1, RPB2, and β-tubulin) among 80 P. lilacinus specimens collected from 7 locations in China. Various degrees of polymorphism and haplotype diversity were observed among the six gene fragments. However, no genetic differentiation was observed among the geographic populations, consistent with extensive gene flow among these geographic populations of P. lilacinus in China. Our analysis also suggested that clonal reproduction was the predominant mode of reproduction in natural populations of P. lilacinus.