A Robust Bayesian Probabilistic Matrix Factorization Model for Collaborative Filtering Recommender Systems Based on User Anomaly Rating Behavior Detection

( 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.

Improved K-means Algorithm with the Pretreatment of PCA Dimension Reduction

Hongtao Liu,Chen Fang,Yu Wu,Ke Xu,Tian Dai 보안공학연구지원센터 2015 International Journal of Hybrid Information Techno Vol.8 No.6

Prediction and Identification of an Acid-inducible Promoter from Lactococcus lactis ssp. cremoris MG1363

Hongxian Yu,Wentao Xu,Yunbo Luo,Jing He,Hongtao Tian,Hui Shi,Xiaohong Mei 한국식품과학회 2015 Food Science and Biotechnology Vol.24 No.5

Using a promoter online prediction system, the gene sequence of GroEL protein from Lactococcus lactis ssp. cremoris MG1363 was analysed and a putative promoter, designated as gro, was further studied. Under acidic conditions, gro showed preliminary promoter function by driving the expression of lacZ reporter gene in Escherichia coli DH5α. In addition, gro drove the gene expression of GroEL and green fluorescent protein. In this paper, an acid-inducible promoter was successfully identified. This promoter has a wide prospect in the field of biotechnology.

Shaping of the 3D genome by the ATPase machine cohesin

Kim Yoori,Yu Hongtao 생화학분자생물학회 2020 Experimental and molecular medicine Vol.52 No.-

The spatial organization of the genome is critical for fundamental biological processes, including transcription, genome replication, and segregation. Chromatin is compacted and organized with defined patterns and proper dynamics during the cell cycle. Aided by direct visualization and indirect genome reconstruction tools, recent discoveries have advanced our understanding of how interphase chromatin is dynamically folded at the molecular level. Here, we review the current understanding of interphase genome organization with a focus on the major regulator of genome structure, the cohesin complex. We further discuss how cohesin harnesses the energy of ATP hydrolysis to shape the genome by extruding chromatin loops.

Chemical Vapor Deposition Growth of Graphene Domains Across the Cu Grain Boundaries

Yang Wang,Yu Cheng,Yunlu Wang,Shuai Zhang,Chen Xu,Xuewei Zhang,Miao Wang,Yang Xia,Qunyang Li,Pei Zhao,Hongtao Wang 성균관대학교(자연과학캠퍼스) 성균나노과학기술원 2018 NANO Vol.13 No.08

Many aspects in the chemical vapor deposition (CVD) growth of graphene remain unclear such as its behavior near the catalyst grain boundaries. Here we investigate the CVD growth mechanism of graphene across the Cu grain boundaries using unidirectional aligned graphene domains, which simplifies the analysis of both graphene and Cu to a large extent. We found that for a graphene domain grown across the Cu grain boundary, the domain orientation is determined by the Cu grain where the domain nucleation center is located, and the Cu grain boundary will not change the growth behavior for this graphene domain. This growth mechanism is consistent with the Custep-attached nucleation and edge-attachment-limited growth mechanism for H-terminated graphene domains and will provide more guidance for the synthesis of high-quality graphene with less domain boundaries.

Dynamic positioning error analysis and modeling of CNC machine tool guideway system

Li Li,Hongtao Yang,Yu Zhang,Qun Ma 대한기계학회 2021 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.35 No.5

The dynamic characteristics of the XY worktable are thoroughly analyzed in this study to accurately compensate the measurement errors of on-machine measurement systems caused by the dynamic and static characteristics under multiple factors. The dynamic positioning error model of the XY worktable motion components is established, and the theoretical model of the dynamic positioning error of the XY worktable is derived. The actual parameters of the experimental platform for the correlation error of CNC machine tools are substituted into the model for theoretical calculation and analysis. Results show that the motion speed of the worktable, the weight of the measured workpiece, the installation position of the workpiece, and the friction force are the main factors causing the dynamic positioning error. Dynamic positioning error analysis and verification experiments were conducted to verify the validity of the proposed theoretical model. Experimental results show that a regular change occurs between the dynamic positioning error and the movement speed of the XY worktable, and the actual measurement results are basically consistent with the theoretical calculation results. The research results can lay a good foundation for establishing the measurement error prediction and compensation model of on-machine measurement systems of CNC machine tools and improving its measurement accuracy.

Insulin receptor endocytosis in the pathophysiology of insulin resistance

Catherine Hall,Hongtao Yu,Eunhee Choi 생화학분자생물학회 2020 Experimental and molecular medicine Vol.52 No.-

Insulin signaling controls cell growth and metabolic homeostasis. Dysregulation of this pathway causes metabolic diseases such as diabetes. Insulin signaling pathways have been extensively studied. Upon insulin binding, the insulin receptor (IR) triggers downstream signaling cascades. The active IR is then internalized by clathrin-mediated endocytosis. Despite decades of studies, the mechanism and regulation of clathrin-mediated endocytosis of IR remain incompletely understood. Recent studies have revealed feedback regulation of IR endocytosis through Src homology phosphatase 2 (SHP2) and the mitogen-activated protein kinase (MAPK) pathway. Here we review the molecular mechanism of IR endocytosis and its impact on the pathophysiology of insulin resistance, and discuss the potential of SHP2 as a therapeutic target for type 2 diabetes.

A review of the transmission tower-line system performance under typhoon in wind tunnel test

Xianying Li,Yu Yao,Hongtao Wu,Biao Zhao,Bin Chen,Tao Yi 한국풍공학회 2019 Wind and Structures, An International Journal (WAS Vol.29 No.2

As a regenerated turbulent wind field process, wind tunnel test has proven to be a promising approach for investigating the transmission tower-line system (TTLS) performance in view of experimental scaled models design, simulation techniques of wind field, and wind induced responses subjected to typhoon. However, the challenges still remain in using various wind tunnels to regenerate turbulent wind field with considerable progress having been made in recent years. This review paper provides an overview of the state-of-the-art of the wind tunnel based on active or passive controlled simulation techniques. Specific attention and critical assessment have been given to: (a) the design of experimental scaled models, (b) the simulation techniques of wind field, and (c) the responses of TTLS subjected to typhoon in wind tunnel. This review concludes with the research challenges and recommendations for future research direction.

The hydrogen storage nanomaterial MgH2 improves irradiation-induced male fertility impairment by suppressing oxidative stress

Jing Ma,Suhe Dong,Hongtao Lu,Zhongmin Chen,Huijie Yu,Xuejun Sun,Renjun Peng,Wei Li,Sinian Wang,Qisheng Jiang,Fengsheng Li,Li Ma 한국생체재료학회 2022 생체재료학회지 Vol.26 No.2

Objective: This study aimed to reveal the protective effect of hydrogen storage nanomaterial MgH2 on radiationinduced male fertility impairment. Methods: The characterization of MgH2 were analyzed by scanning electron microscopy (SEM) and particle size analyzer. The safety of MgH2 were evaluated in vivo and in vitro. The radioprotective effect of MgH2 on the reproductive system were analyzed in mice, including sperm quality, genetic effect, spermatogenesis, and hormone secretion. ESR, flow cytometry and western blotting assay were used to reveal the underlying mechanisms. Results: MgH2 had an irregular spherical morphology and a particle size of approximately 463.2 nm, and the content of Mg reached 71.46%. MgH2 was safe and nontoxic in mice and cells. After irradiation, MgH2 treatment significantly protected testicular structure, increased sperm density, improved sperm motility, reduced deformity rates, and reduced the genetic toxicity. Particularly, the sperm motility were consistent with those in MH mice and human semen samples. Furthermore, MgH2 treatment could maintain hormone secretion and testicular spermatogenesis, especially the generation of Sertoli cells, spermatogonia and round sperm cells. In vitro, MgH2 eliminated the [·OH], suppressed the irradiation-induced increase in ROS production, and effectively alleviated the increase in MDA contents. Moreover, MgH2 significantly ameliorated apoptosis in testes and cells and reversed the G2/M phase cell cycle arrest induced by irradiation. In addition, MgH2 inhibited the activation of radiation-induced inflammation and pyroptosis. Conclusion: MgH2 improved irradiation-induced male fertility impairment by eliminating hydroxyl free radicals.

Novel In Situ Synthesized Fe@C Magnetic Nanocapsules Used as Adsorbent for Removal of Organic Dyes and Its Recycling

Ranran Li,Jieyi Yu,Asif Shah,Xinglong Dong,Xiaona Li,Hongtao Yu,Xie Quan,Youngguan Jung 성균관대학교(자연과학캠퍼스) 성균나노과학기술원 2016 NANO Vol.11 No.2

Core/shell type carbon-coated Fe nanocapsules (Fe@C NCs) were in situ synthesized by DC arcdischarge plasma method in methane atmosphere. Such Fe nanocapsules have saturation magnetization of 29.32 emu/g and specific surface area of 85.86 m2/g. The carbon shell of Fe@C NCs was functionalized with oxygen-containing groups (such as –OH or –COOH) by using H2O2. The adsorption of organic dye, e.g., methylene blue (MB) was systematically investigated in different conditions, such as contact time, pH values and temperature. The maximum adsorption capacity (46.5 mg/g) was calculated by fitting the adsorption isotherms with Langmuir model, coincident with the experimental result of 44.5 mg/g. Kinetics data supported pseudo-second order model, and the thermodynamic process of adsorption was revealed as endothermic and spontaneous physisorption. The MB-absorbed Fe@C NCs can be entirely separated from the contaminative solution by a magnetic field and then successfully cycled for regeneration. After repetitive cycles of the adsorption/desorption experiments for five times, the removal efficiency can be maintained over 90%.