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A new algorithm based on the proximity principle for the virtual network embedding problem

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Journal of Zhejiang University-Science C(Computers and Electronics) 2011年第11期12卷 910-918页

作者： Jiang LIU Tao HUANG Jian-ya chen yun-jie LIU Key Laboratory of Universal Wireless Communications of Ministry of Education Beijing University of Post and Telecommunications Beijing 100876 China

The virtual network embedding/mapping problem is a core issue of network virtualization. It is concerned mainly with how to map virtual network requests to the substrate network efficiently. There are two steps in this problem: node mapping and link mapping. Current studies mainly focus on developing heuristic algorithms, since both steps are computationally intractable. In this paper, we propose a new algorithm based on the proximity principle, which considers the distance factor besides the capacity factor in the node mapping step. Thus, the two steps of the embedding problem can be better integrated and the substrate network resource can be used more efficiently. Simulation results show that the new algorithm greatly enhances the performance of the revenue/cost (R/C) ratio, acceptance ratio, and runtime of the embedding problem.

关键词： Virtual network embedding Proximity Revenue/cost (R/C) ratio Acceptance ratio Runtime

DNA methylation-dependent epigenetic regulationof Verticillium dahliae virulence in p

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aBIOTECH 2023年第3期4卷 185-201页

作者： yun-ya chen chen Zhu Jian-Hua Zhao Ting Liu Feng Gao Ying-Chao Zhang cheng-Guo Duan Shanghai Center for Plant Stress Biology and Center of Excellence in Molecular Plant Sciences Chinese Academy of ScienceShanghai 200032China University of Chinese Academy of Sciences Beijing 100049China College of Life Sciences Anhui Normal UniversityWuhu 241000China State Key Laboratory of Plant Genomics Institute of MicrobiologyChinese Academy of SciencesBeijing 100101China Qilu Zhongke Academy of Modern Microbiology Technology Jinan 250000China

As a conserved epigenetic mark, DNA cytosine methylation, at the 5’ position (5-mC), plays importantroles in multiple biological processes, including plant immunity. However, the involvement of DNAmethylation in the determinants of virulence of phytopathogenic fungi remains elusive. In this study,we profiled the DNA methylation patterns of the phytopathogenic fungus Verticillium dahliae, one of themajor causal pathogens of Verticillium wilt disease that causes great losses in many crops, and exploredits contribution in fungal pathogenicity. We reveal that DNA methylation modification is present in *** and is required for its full virulence in host plants. The major enzymes responsible for theestablishment of DNA methylation in V. dahliae were identified. We provided evidence that DNAmethyltransferase-mediated establishment of DNA methylation pattern positively regulates fungalvirulence, mainly through repressing a conserved protein kinase VdRim15-mediated Ca2? signaling andROS production, which is essential for the penetration activity of V. dahliae. In addition, we furtherdemonstrated that histone H3 lysine 9 trimethylation (H3K9me3), another heterochromatin markerthat is closely associated with 5-mC in eukaryotes, also participates in the regulation of V. dahliaepathogenicity, through a similar mechanism. More importantly, DNA methyltransferase genes VdRid,VdDnmt5, as well as H3K9me3 methyltransferase genes, were greatly induced during the early infection phase, implying that a dynamic regulation of 5-mC and H3K9me3 homeostasis is required for anefficient infection. Collectively, our findings uncover an epigenetic mechanism in the regulation ofphytopathogenic fungal virulence.

关键词： DNA methylation Verticillium dahliae Pathogenicity H3K9me3

Pars plana vitrectomy with internal limiting membrane plugging assisted by autologous blood for optic disc pit associated with vitreomacular traction

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International Journal of Ophthalmology(English edition) 2024年第10期17卷 1957-1959页

作者： Bin chen yan-Ting Li Tian-Hong Wu ya-Ping Yuan yun-Feng Lu Department of Ophthalmology Suzhou EENT HospitalSuzhou 215000Jiangsu ProvinceChina Department of Ophthalmology the First Affiliated Hospital of Soochow UniversitySuzhou 215000Jiangsu ProvinceChina

Dear Editor,We report a case of optic disc pit(ODP)associated with vitreomacular traction which has been successfully treated by a combined *** have obtained the written informed consent from the patient,and this case... 详细信息

关键词： technique. traction macular

Synergistic Effect of Schwann Cells and Retinoic Acid on Differentiation and Synaptogenesis of Hippocampal Neural Stem Cells in vitro

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Biomedical and Environmental Sciences 2006年第3期19卷 219-224页

作者： XUE-BAO ZHANG YUAN-SHAN ZENG WEI ZHANG ya-yun chen YI XIONG SUI-JUN chen Division of Neuroscience Department of Histology and Embryology Zhongshan Medical College Sun Yat-Sen University Guangzhou 510080 Guangdong China

Objective To investigate the synergistic effect of Schwann cells （SCs） and retinoic acid （R.A） on differentiation and synaptogenesis of neural stem cells （NSCs） derived from hippocampus of neonatal rats. Methods The classical method for 2×2 factorial analysis experiment was used to assess synergistic action of SCs and RA. NSCs were treated with R.A, SCs, and SCs ＋ RA in DMEM/F12 with 0.5% fetal bovine serum for six days, respectively. Double immunofluorescent staining was used to detect the differentiation of NSCs including nestin, glial fibrillary acidic protein （GFAP） and Map2. The expression of PSD95 was used to demonstrate synaptogenesis. Results After NSCs were treated with RA or SCs, the expression of nestin and GFAP was significantly decreased while the expression of Map2 and PSD95 was significantly increased in comparison with the control. Factorial ANOVA showed that interactions between SCs and RA could induce the expression of Map2 and PSD95. Conclusion SCs and RA could promote synergistically the neuronal differentiation and synaptogenesis of hippocampal neural stem cells in vitro while they decreased the astrocytes and nestin positive NSCs.

关键词： Neural stem cell Neuronal differentiation PSD95 Schwann cells Retinoic acid

Fixed-Time Anti-Disturbance Average-Tracking for Multi-Agent Systems Without Velocity Measurements

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Journal of Systems Science & Complexity 2024年第3期37卷 985-1002页

作者： LI Yuling LIU chenglin ZHANG ya chen yangyang Key Laboratory of Advanced Process Control for Light Industry(Ministry of Education) Institute of AutomationJiangnan UniversityWuci 214122China School of Automation Southeast UniversityNanjing 210096China

In this paper,the authors tackle a fixed-time average-tracking problem for multi-agent systems which do not require velocity measurements and are affected by external mismatched and matched *** objective requires the considered agents with second-order dynamics to follow the average value of several time-varying reference signals,each of which is acquired by only one *** of all,the average value is estimated by using a novel distributed average estimator in a fixed ***,an original observer is created to provide estimated values in a fixed time for external mismatched and matched disturbances as well as unmeasured velocities of ***,the authors propose a novel fixed-time anti-disturbance average-tracking protocol with the aid of the observer and a sliding mode *** the end,the feasibility of theoretical analysis is illustrated by some simulation experiments.

关键词： Average-tracking control fixed-time algorithm fixed-time observer mismatched distur-bances multi-agent systems velocity measurements

Chain Dynamics Heterogeneity in Plasticized Poly(vinyl butyral)(PVB) as Elucidated by Solid-State NMR

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Chinese Journal of Polymer Science 2024年第1期42卷 113-124,I0010页

作者： Jing Lv Xu chen Zi-Shuo Wu ya-Hui Li Wei chen National Synchrotron Radiation Laboratory Anhui Provincial Engineering Laboratory of Advanced Functional Polymer FilmCAS Key Laboratory of Soft Matter ChemistryUniversity of Scienceand Technology of ChinaHefei 230026China

The chain dynamics heterogeneity of the poly(vinyl butyral)(PVB) plasticized by triethylene glycol bis(2-ethylhexa noate)(TEG-EH) was investigated by various solid-state NMR *** plasticized PVB shows two domains in distinct molecular dynamics differences,namely,rigid and soft domains,where the latter is the plasticizer-rich *** time domain low field NMR was first used to investigate the dynamics heterogeneity of the plasticized PVB,and the results show the decreasing activated energy of components in the soft domain of plasticized PVB(E_a=20.2 kJ/mol) as compared with that of the pristine one(E_a=24.3 kJ/mol).Detailed dynamics heterogeneity was obtained by high-field NMR with site-specific *** quadrupole-echo ~2H-NMR was adopted to elucidate the dynamics heterogeneity of the vinyl alcohol(VA) units,where only the hydroxyl group of VA is *** ~1H-^(13)C WISE NMR spectra show that there is not much difference in the mobility of the VB unit in PVB with and without plasticizer,whereas the glass transition temperature differed by approximately 53℃.This is further supported by Torchia's T_1 relaxation *** origin of such an unusual phenomenon is attributed to the critical role of the remaining VA(~22%) in the soft domain,where the VA units locally aggregate through hydrogen ***,the existence of a mobility gradient in the VB unit has been ***,the mobility difference for VB with different stereo-geometry(meso or racemic conformation) is observed for the first *** indicates the importance of modulating the ratio of meso over racemic VB for controlling the macroscopic perfo rmance of PVB.

关键词： Poly(vinyl butyral) Dynamics heterogeneity Plasticizer Solid state NMR

Mechanical Performance of Bio-inspired Bidirectional Corrugated Sandwich Pressure Shell Under External Hydrostatic Pressure

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China Ocean Engineering 2024年第2期38卷 297-312页

作者： ZHANG Yi chen Yue yun Lai LIANG Xu Ocean College Zhejiang UniversityZhoushan 316000China Hainan Institute Zhejiang UniversitySanya 572000China

This paper aims to enhance the compression capacity of underwater cylindrical shells by adopting the corrugated sandwich structure of *** cuttlebone suffers uniaxial external compression,while underwater cylindrical shells are in a biaxial compressive stress *** suit the biaxial compressive stress state,a novel bidirectional corrugated sandwich structure is proposed to improve the bearing capacity of cylindrical *** static and buckling analysis for the sandwich shell and the unstiffened cylindrical shell with the same volume-weight ratio are studied by numerical *** is indicated that the proposed sandwich shell can effectively reduce the ratio between circumferential and axial stress from 2 to 1.25 and improve the critical buckling load by about 1.63 *** simulation shows that optimizing and adjusting the structural parameters could significantly improve the advantage of the sandwich ***,the hydrostatic pressure tests for shell models fabricated by 3D printing are carried *** to the experimental results,the overall failure position of the sandwich shell is at the center part of the sandwich *** has been found the average critical load of the proposed sandwich shell models exceeds two times that of the unstiffened shell ***,the proposed bio-inspired bidirectional corrugated sandwich structure can significantly enhance the pressure resistance capability of cylindrical shells.

关键词： bio-inspiration bidirectional corrugation sandwich shell external pressure buckling

Degradation-adaptive neural network for jointly single image dehazing and desnowing

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Frontiers of Computer Science 2024年第2期18卷 247-249页

作者： Erkang chen Sixiang chen Tian YE yun LIU School of Ocean Information Engineering Jimei UniversityXiamen 361021 China College of Artificial Intelligence Southwest UniversityChongqing 400715 China

1 Introduction In harsh winter scenes,the captured images often suffer from hazeand snowdegradationssimultaneously,which significantly affect the performance of high-level computer vision ***,most existing dehazing methods[1-4]and desnowing methods[5-7]are specialized to address only one type of weather-related degradation,and they struggle to effectively handle multiple types of degradations.

关键词： neural handle computer

Stability of the Phase Separation State for Compressible Navier-Stokes/Allen-Cahn System

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Acta Mathematicae Applicatae Sinica 2024年第1期40卷 45-74页

作者： ya-zhou chen Hakho Hong Xiao-ding Shi Department of Mathematics College of Mathematics and PhysicsBeijing University of Chemical TechnologyBeijing100029China Institute of Mathematics State Academy of SciencesPyongyangKorea

This paper is concerned with the large time behavior of the Cauchy problem for Navier-Stokes/AllenCahn system describing the interface motion of immiscible two-phase flow in 3-D. The existence and uniqueness of global solutions and the stability of the phase separation state are proved under the small initial perturbations. Moreover, the optimal time decay rates are obtained for higher-order spatial derivatives of density,velocity and phase. Our results imply that if the immiscible two-phase flow is initially located near the phase separation state, then under small perturbation conditions, the solution exists globally and decays algebraically to the complete separation state of the two-phase flow, that is, there will be no interface fracture, vacuum, shock wave, mass concentration at any time, and the interface thickness tends to zero as the time t → +∞.

关键词： Navier-Stokes/Allen-Cahn system existence uniqueness large time behavior decay rate