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( Hongtao Yu ),( Lijun Sun ),( Fuzhi Zhang ) 한국인터넷정보학회 2019 KSII Transactions on Internet and Information Syst Vol.13 No.9
Collaborative filtering recommender systems are vulnerable to shilling attacks in which malicious users may inject biased profiles to promote or demote a particular item being recommended. To tackle this problem, many robust collaborative recommendation methods have been presented. Unfortunately, the robustness of most methods is improved at the expense of prediction accuracy. In this paper, we construct a robust Bayesian probabilistic matrix factorization model for collaborative filtering recommender systems by incorporating the detection of user anomaly rating behaviors. We first detect the anomaly rating behaviors of users by the modified K-means algorithm and target item identification method to generate an indicator matrix of attack users. Then we incorporate the indicator matrix of attack users to construct a robust Bayesian probabilistic matrix factorization model and based on which a robust collaborative recommendation algorithm is devised. The experimental results on the MovieLens and Netflix datasets show that our model can significantly improve the robustness and recommendation accuracy compared with three baseline methods.
Hongtao Shen,Weicheng Hu,Qing-shan Yang,Fucheng Yang,Kunpeng Guo,Tong Zhou,Guowei Qian,Qinggen Xu,Ziting Yuan 한국풍공학회 2022 Wind and Structures, An International Journal (WAS Vol.35 No.6
In wind-resistant designs, wind velocity is assumed to be a Gaussian process; however, local complex topography may result in strong non-Gaussian wind features. This study investigates the non-Gaussian wind features over complex terrain under atmospheric turbulent boundary layers by the large eddy simulation (LES) model, and the turbulent inlet of LES is generated by the consistent discretizing random flow generation (CDRFG) method. The performance of LES is validated by two different complex terrains in Changsha and Mianyang, China, and the results are compared with wind tunnel tests and onsite measurements, respectively. Furthermore, the non-Gaussian parameters, such as skewness, kurtosis, probability curves, and gust factors, are analyzed in-depth. The results show that the LES method is in good agreement with both mean and turbulent wind fields from wind tunnel tests and onsite measurements. Wind fields in complex terrain mostly exhibit a left-skewed Gaussian process, and it changes from a softening Gaussian process to a hardening Gaussian process as the height increases. A reduction in the gust factors of about 2.0%-15.0% can be found by taking into account the non-Gaussian features, except for a 4.4% increase near the ground in steep terrain. This study can provide a reference for the assessment of extreme wind loads on structures in complex terrain.
Hongtao Ma,Yuyang Zhao,Yiran Feng,이응주,Xue-Heng Tao 한국멀티미디어학회 2021 The journal of multimedia information system Vol.8 No.2
Under the time-varying temperature, the high-temperature radiation of forgings and the change of reflection characteristics of oxide skin on the surface of forgings lead to the difficulty of obtaining images to truly reflect the geometric characteristics of forgings. It is urgent to study the clear and reliable acquisition method of hot forging feature image under time-varying temperature to meet the requirements of visual measurement of hot geometric parameters of forgings. Based on this, this chapter first puts forward the quality evaluation method of forging feature image, which provides guarantee for the accurate evaluation of feature image quality. Furthermore, the factors that affect the image quality, such as the radiation characteristics of forgings and the photographic characteristics of cameras, are analyzed, and the imaging spectrum which can effectively suppress the radiation intensity of forgings is determined. Finally, aiming at the problem that the quality of image acquisition is difficult to guarantee due to the drastic change of radiation intensity of forgings under time-varying temperature, an image acquisition method based on minimum signal-to-noise ratio (SNR) based laser light intensity adaptation is proposed, which significantly improves the definition of feature light strips in forging images at high temperature, and finally realizes the clear acquisition of feature images of large-scale hot forging under time-varying temperature.
Molecular discrimination of Panax ginseng cultivar K-1 using pathogenesis-related protein 5 gene
Hongtao Wang,Fengjiao Xu,Xinqi Wang,권우생,Deok Chun Yang 고려인삼학회 2019 Journal of Ginseng Research Vol.43 No.3
Background: The mixed-cultivation of different Panax ginseng cultivars can cause adverse effects onstability of yield and quality. K-1 is a superior cultivar with good root shape and stronger diseaseresistance. DNA markers mined from functional genes are clearly desirable for K-1, as they may associatewith major traits and can be used for marker-assisted selection to maintain the high quality of Koreanginseng. Methods: Five genes encoding pathogenesis-related (PR) proteins of P. ginseng were amplified andcompared for polymorphism mining. Primary, secondary, and tertiary structures of PR5 protein wereanalyzed by ExPASy-ProtParam, PSSpred, and I-TASSER methods, respectively. A coding single nucleotidepolymorphism (SNP)ebased specific primer was designed for K-1 by introducing a destabilizingmismatch within the 30 end. Allele-specific polymerase chain reaction (PCR) and real-time allele-specificPCR assays were conducted for molecular discrimination of K-1 from other cultivars and landraces. Results: A coding SNP leading to the modification of amino acid residue from aspartic acid to asparaginewas exploited in PR5 gene of K-1 cultivar. Bioinformatics analysis showed that the modification of aminoacid residue changed the secondary and tertiary structures of the PR5 protein. Primer KSR was designedfor specific discrimination of K-1 from other ginseng cultivars and landraces. The developed real-timeallele-specific PCR assay enabled easier automation and accurate genotyping of K-1 from a large numberof ginseng samples. Conclusion: The SNP marker and the developed real-time allele-specific PCR assay will be useful not onlyfor marker-assisted selection of K-1 cultivar but also for quality control in breeding and seed programs ofP. ginseng.
( Hongtao Liu ),( Seng Zhu ),( Yingying Sun ),( Na Li ),( Jingmin Gu ),( Changjiang Sun ),( Xin Feng ),( Wenyu Han ),( Jianxia Jiang ),( Liancheng Lei ) 한국미생물 · 생명공학회 2017 Journal of microbiology and biotechnology Vol.27 No.1
Meningitis caused by Streptococcus suis serotype 2 (S. suis 2) is a great threat to the pig industry and human health. Virulence factors associated with the pathogenesis of meningitis have yet to be clearly defined, even though many potential S. suis 2 virulence factors have been identified. This greatly hinders the progress of S. suis 2 meningitis pathogenesis research. In this study, a co-culture blood-brain barrier (BBB) model was established using primary porcine brain microvascular endothelial cells and astrocytes, and the whole genome library of S. suis 2 was constructed using phage display technology. Finally, a total of 14 potential virulence factors contributing to S. suis 2 adherence to and invasion of the BBB were selected by analyzing the interactions between the phage library and the co-culture model. Twelve of these factors have not been previously reported in meningitis-related research. The data provide valuable insight into the pathogenesis of S. suis 2 meningitis and potential targets for the development of drug therapies.