Block Sparse Low-rank Matrix Decomposition based Visual Defect Inspection of Rail Track Surfaces

( Linna Zhang ),( Shiming Chen ),( Yigang Cen ),( Yi Cen ),( Hengyou Wang ),( Ming Zeng ) 한국인터넷정보학회 2019 KSII Transactions on Internet and Information Syst Vol.13 No.12

Low-rank matrix decomposition has shown its capability in many applications such as image in-painting, de-noising, background reconstruction and defect detection etc. In this paper, we consider the texture background of rail track images and the sparse foreground of the defects to construct a low-rank matrix decomposition model with block sparsity for defect inspection of rail tracks, which jointly minimizes the nuclear norm and the 2-1 norm. Similar to ADM, an alternative method is proposed in this study to solve the optimization problem. After image decomposition, the defect areas in the resulting low-rank image will form dark stripes that horizontally cross the entire image, indicating the preciselocations of the defects. Finally, a two-stage defect extraction method is proposed to locate the defect areas. The experimental results of the two datasets show that our algorithm achieved better performance compared with other methods.

Research trends in biomimetic medical materials for tissue engineering: 3D bioprinting, surface modification, nano/micro-technology and clinical aspects in tissue engineering of cartilage and bone

Cen Chen,Sumi Bang,Younghak Cho,Sahnghoon Lee,이인섭,ShengMin Zhang,노인섭 한국생체재료학회 2016 생체재료학회지 Vol.20 No.2

This review discusses about biomimetic medical materials for tissue engineering of bone and cartilage, after previous scientific commentary of the invitation-based, Korea-China joint symposium on biomimetic medical materials, which was held in Seoul, Korea, from October 22 to 26, 2015. The contents of this review were evolved from the presentations of that symposium. Four topics of biomimetic medical materials were discussed from different research groups here: 1) 3D bioprinting medical materials, 2) nano/micro-technology, 3) surface modification of biomaterials for their interactions with cells and 4) clinical aspects of biomaterials for cartilage focusing on cells, scaffolds and cytokines.

Research on UAV access deployment algorithm based on improved virtual force model

Shuchang Zhang,Duanpo Wu,Lurong Jiang,Xinyu Jin,Shuwei Cen 한국인터넷정보학회 2022 KSII Transactions on Internet and Information Syst Vol.16 No.8

In this paper, a unmanned aerial vehicle (UAV) access deployment algorithm is proposed, which is based on an improved virtual force model to solve the poor coverage quality of UAVs caused by limited number of UAVs and random mobility of users in the deployment process of UAV base station. First, the UAV-adapted Harris Hawks optimization (U-AHHO) algorithm is proposed to maximize the coverage of users in a given hotspot. Then, a virtual force improvement model based on user perception (UP-VFIM) is constructed to sense the mobile trend of mobile users. Finally, a UAV motion algorithm based on multi-virtual force sharing (U-MVFS) is proposed to improve the ability of UAVs to perceive the moving trend of user equipments (UEs). The UAV independently controls its movement and provides follow-up services for mobile UEs in the hotspot by computing the virtual force it receives over a specific period. Simulation results show that compared with the greedy-grid algorithm with different spacing, the average service rate of UEs of the U-AHHO algorithm is increased by 2.6% to 35.3% on average. Compared with the baseline scheme, using UP-VFIM and U-MVFS algorithms at the same time increases the average of 34.5% to 67.9% and 9.82% to 43.62% under different UE numbers and moving speeds, respectively.

Induction of Salivary Gland-Like Tissue by Induced Pluripotent Stem Cells In Vitro

Meng Cen,Huang Shengyuan,Cheng Taiqi,Zhang Xue,Yan Xing 한국조직공학과 재생의학회 2022 조직공학과 재생의학 Vol.19 No.2

Background: To investigate the in vitro induction of salivary gland-like tissue by ips cells in an interferon regulatory factor 6 (IRF6) overexpression and parotid conditioned medium environment. Methods: Urine-derived ips cells were isolated, identified, transfected with IRF6 and cultured in parotid conditioned medium to induce ips cells into salivary gland differentiation, morphological changes of ips cells were observed, CCK-8 was used to determine the cell proliferation efficiency and transcriptome sequencing was used to detect the expression of genes related to parotid gland formation. Results: Immunofluorescence staining showed that the isolated ips cells were positive for NANOG, SSEA4 and OCT4 and had embryonic-like stem cell characteristics; CCK-8 showed that there was no statistical difference in the proliferation efficiency between the IRF6+ induced group and the simple induced group after induction of ips cells into salivary glands. The results of transcriptome sequencing showed that there were a total of 643 differentially expressed genes, including 365 up-regulated genes and 278 down-regulated genes in the IRF6+ induced group compared to the blank control group, and the salivary gland related genes HAPLN1, CCL2, MSX2, ANXA1, CYP11A1, HES1 and LUM were all highly expressed in the IRF6+ induced group. Conclusion: IRF6 promotes salivary gland differentiation in urine-derived iPSCs, and its mechanism of promoting differentiation may be that IRF6 upregulates the expression of HAPLN1, CCL2, MSX2, ANXA1, CYP11A1, HES1 and LUM to promote epithelial differentiation.

Study of the Cavitation Phenomenon Inside Roller Vane Pump

Bin Zhang,Chun-xiao Zhao,Hao-cen Hong,Da-peng Bai,Hua-yong Yang 한국유체기계학회 2021 International journal of fluid machinery and syste Vol.14 No.1

The roller vane pumps are widely used in the automobile industry as steering pumps. However, the cavitation damage near the outlet relief groove could directly decrease serve life and efficiency of the roller vane pump. In this paper, the mechanism of the cavitation is discussed, especially the cavitation damage near the tip of the relief groove. The computational fluid dynamics simulation method (CFD) based on dynamic meshing technique and user defined function (UDF) is applied to calculate flow dynamics and multi-phase flow characteristics, especially the flows inside the fluid film between the stator and valve plate. The simulated results show that the cavitation region is the same with the experiment one, and the cavitation inside the fluid film is caused by the shear action of the stator and valve plate. The negative pressure region near the relief groove has an extreme low pressure at 0.08 MPa, and the maximum flow velocity is 99.3 m/s. Besides, the cavitation region near the relief groove has the highest gas volume fraction of 2.23% and the lowest density of 560 kg/m3. Furthermore, the reason why cavitation happened at this position in a roller vane pump is analyzed by theoretical analysis.

Analysis and Optimization on U-shaped Damping Groove for Flow Ripple Reduction of Fixed Displacement Axial-Piston Pump

Hao-cen HONG,Bin ZHANG,Min YU,Qi ZHONG,Hua-yong YANG 한국유체기계학회 2020 International journal of fluid machinery and syste Vol.13 No.1

The periodic flow ripples and pressure pulsations in a fixed-displacement axial-piston pump will directly impact its dynamic characteristics. To reduce the discharge flow ripples and pressure pulsations is one of the design challenges. An optimizing method is investigated herein using numerical models. The U-shaped damping groove at the discharge kidney groove is the primary optimized object. The numerical models of a fixed-displacement axial-piston pump with nine pistons are proposed and developed by MATLAB/Simulink. The effects of width radius, groove depth and groove length angle on flow dynamics are discussed. The optimization models based on the root-mean-square, the pulsation and the suction-extrusion ratio are proposed. As results show that the optimized structure can decrease the flow ripples from 31.08% to 20.33%.

Immobilizing osteogenic growth peptide with and without fibronectin on a titanium surface: effects of loading methods on mesenchymal stem cell differentiation

Chen, Cen,Li, Han,Kong, Xiangdong,Zhang, Sheng-Min,Lee, In-Seop Dove Medical Press 2015 INTERNATIONAL JOURNAL OF NANOMEDICINE Vol.10 No.-

<P>In this study, to improve the osseointegration of implants, osteogenic growth peptide (OGP) and fibronectin (FN) were loaded within mineral, which was formed on titanium, through adsorption and coprecipitation methods. The release profiles of OGP loaded by either adsorption or coprecipitation and the effects of the loading methods to immobilize OGP with and without FN on rat mesenchymal stem cell (rMSC) osteogenic differentiation were studied. The coprecipitation approach slightly reduced the initial burst release, while the adsorption approach provided a more sustained release. Dual loading of OGP and FN further improved cell attachments compared with either OGP or FN alone. Dually loaded OGP and FN also had a positive impact on rMSC proliferation and osteogenic differentiation. The difference in methods of loading OGP with and without FN also had some effects on osteogenic differentiation. Compared with coprecipitated OGP alone, adsorbed OGP enhanced later differentiation, such as osteocalcin secretion and matrix mineralization. Simultaneously adsorbed OGP and FN led to higher proliferation and higher osteogenic differentiation in both early and late stages compared with sequentially loaded OGP and FN. rMSC culture clearly indicated that simultaneously adsorbed OGP and FN could improve osseointegration, and this treatment represents a potential method for effective surface modification of dental and orthopedic implants.</P>

Greeting, Function, and Music: How Users Chat with Voice Assistants

Ji Wang,Han Zhang,Cen Zhang,Junjun Xiao,Seung Hee Lee 한국감성과학회 2020 감성과학 Vol.23 No.2

Voice user interface has become a commercially viable and extensive interaction mechanism with the development of voice assistants. Despite the popularity of voice assistants, the academic community does not utterly understand about what, when, and how users chat with them. Chatting with a voice assistant is crucial as it defines how a user will seek the help of the assistant in the future. This study aims to cover the essence and construct of conversational AI, to develop a classification method to deal with user utterances, and, most importantly, to understand about what, when, and how Chinese users chat with voice assistants. We collected user utterances from the real conventional database of a commercial voice assistant, NetEase Sing in China. We also identified different utterance categories on the basis of previous studies and real usage conditions and annotated the utterances with 17 labels. Furthermore, we found that the three top reasons for the usage of voice assistants in China are the following: (1) greeting, (2) function, and (3) music. Chinese users like to interact with voice assistants at night from 7 PM to 10 PM, and they are polite toward the assistants. The whole percentage of negative feedback utterances is less than 6%, which is considerably low. These findings appear to be useful in voice interaction designs for intelligent hardware.

Characterization and function of a short peptidoglycan recognition protein from the Chinese oak silkworm, Antheraea pernyi

Li-Shang Dai,Cen Qian, LeiWang,Guo-Qing Wei,Qiu-Ning Liu,Yu Sun,Cong-Fen Zhang,Jun Li,Dong-Ran Liu,Bao-Jian Zhu,Chao-Liang Liu 한국응용곤충학회 2015 Journal of Asia-Pacific Entomology Vol.18 No.4

Peptidoglycan recognition proteins (PGRPs) are conserved proteins in animals from insects to mammals and play an important role in immune response by recognizing peptidoglycan on microbial surfaces. In this study, a PGRP gene from Antheraea pernyi, named Ap-PGRP-A, was isolated and characterized. Sequence analysis revealed that the full-length cDNA of Ap-PGRP-A was 961 bp, containing a 40 bp 5′-untranslated sequence, a 339 bp 3′-untranslated region and an open reading frame of 582 bp. This gene encoded a putative protein of 193 amino acid residues. Phylogenetic analysis indicated that Ap-PGRP-A had the closest protein sequence similarity to Antheraea mylitta PGRP. The recombinant protein was successfully expressed in Escherichia coli cells and a rabbit anti-Ap-PGRP-A antibody was also prepared. Real-time quantitative reverse transcription-PCR analysis showed that Ap-PGRP-A was extensively expressed in the fat body, midgut, hemocyte,malpighian tubule and epidermis of A. pernyi, especially in the fat body and midgut. The expression levels of Ap-PGRP-A were significantly up-regulated by three types of microorganisms, and Ap-PGRP-A expression was more sensitive in response to the Gram-negative bacterium E. coli than the Gram-positive bacterium Bacillus subtilis or the fungus Beauveria bassiana. These data indicate that Ap-PGRP-A may play a role in the innate immune responses of A. pernyi.

Effect of Heat Treatments on Microstructures and Tensile Properties of Cu–3 wt%Ag–0.5 wt%Zr Alloy

Gang Chen,ChuanJie Wang,Ying Zhang,Cen Yi,Peng Zhang 대한금속·재료학회 2018 METALS AND MATERIALS International Vol.24 No.2

The microstructures and tensile properties of Cu–3 wt%Ag–0.5 wt%Zr alloy sheets under different aging treatments areinvestigated in this research. As one kind of precipitate, Ag nanoparticles with coherent orientation relationship with matrixprecipitate. However, after the peak-age point, most of Ag nanoparticles grow into short rod shape with the interface translatingto semi-coherent, which leads to the lower strength of over-aging sample. The yield strength is estimated by consideringsolid solute, grain boundary and precipitation strengthening mechanisms. The result shows that the Ag precipitates providethe main strengthening role. Then a constitutive equation representing the evolution of dislocation density with plastic strainis built by considering work-hardening behavior coming from shearable and non-shearable precipitates which is mainly theparticles containing Zr. The flow stress contributed by shearable particle hardening is higher than that of non-shearable one. Due to the coarsening of grain boundary precipitates and low rate of damage accumulation of these non-shearable particles,the micro-cracks nucleate easily at grain boundary which leads to intergranular fracture.