DSL: Dynamic and Self-Learning Schedule Method of Multiple Controllers in SDN

Junfei Li,Jiangxing Wu,Yuxiang Hu,Kan Li 한국전자통신연구원 2017 ETRI Journal Vol.39 No.3

For the reliability of controllers in a software defined network (SDN), a dynamic and self-learning schedule method (DSL) is proposed. This method is original and easy to deploy, and optimizes the combination of multiple controllers. First, we summarize multiple controllers’ combinations and schedule problems in an SDN and analyze its reliability. Then, we introduce the architecture of the schedule method and evaluate multi-controller reliability, the DSL method, and its optimized solution. By continually and statistically learning the information about controller reliability, this method treats it as a metric to schedule controllers. Finally, we compare and test the method using a given testing scenario based on an SDN network simulator. The experiment results show that the DSL method can significantly improve the total reliability of an SDN compared with a random schedule, and the proposed optimization algorithm has higher efficiency than an exhaustive search.

Multiple Primary Cardiac Malignant Peripheral Nerve Sheath Tumors in the Left Atrium: Case Report

Junfei Li,Qiansu Chen,Shaomei Yu,Siyuan Yang 대한흉부외과학회 2021 Journal of Chest Surgery (J Chest Surg) Vol.54 No.5

Malignant peripheral nerve sheath tumors are rare sarcomas of the heart. Herein, we re- port the case of a 24-year-old man who complained of dyspnea, cough, and upper left back pain. He was found to have multiple primary heart tumors obstructing the right su- perior pulmonary vein in the left atrium, which were diagnosed as malignant peripheral nerve sheath tumors. The patient underwent successful resection of the tumors and im- munohistochemistry was utilized for diagnosis.

Ceramide kinase-mediated C1P metabolism attenuates acute liver injury by inhibiting the interaction between KEAP1 and NRF2

Dongwei Yuan,Li Qing,Lu Xing,Lan Jianfeng,Qiu Zhidong,Wang Xuehong,Wang Junnan,Zheng Xiaojiao,Chen Sifan,Zhang Chong,Jin Junfei 생화학분자생물학회 2024 Experimental and molecular medicine Vol.56 No.-

Acute liver injury is the basis of the pathogenesis of diverse liver diseases. However, the mechanism underlying liver injury is complex and not completely understood. In our study, we revealed that CERK, which phosphorylates ceramide to produce ceramide-1-phosphate (C1P), was the sphingolipid pathway-related protein that had the most significantly upregulated expression during acute liver injury. A functional study confirmed that CERK and C1P attenuate hepatic injury both in vitro and in vivo through antioxidant effects. Mechanistic studies have shown that CERK and C1P positively regulate the protein expression of NRF2, which is a crucial protein that helps maintain redox homeostasis. Furthermore, our results indicated that C1P disrupted the interaction between NRF2 and KEAP1 by competitively binding to KEAP1, which allowed for the nuclear translocation of NRF2. In addition, pull-down assays and molecular docking analyses revealed that C1P binds to the DGR domain of KEAP1, which allows it to maintain its interaction with NRF2. Importantly, these findings were verified in human primary hepatocytes and a mouse model of hepatic ischemia‒reperfusion injury. Taken together, our findings demonstrated that CERK-mediated C1P metabolism attenuates acute liver injury via the binding of C1P to the DGR domain of KEAP1 and subsequently the release and nuclear translocation of NRF2, which activates the transcription of cytoprotective and antioxidant genes. Our study suggested that the upregulation of CERK and C1P expression may serve as a potential antioxidant strategy to alleviate acute liver injury.

Modal identification of time-varying vehicle-bridge system using a single sensor

Wen-Yu He,Yilin Li,Wei-Xin Ren,Junfei Li,Zhi-Wei Chen 국제구조공학회 2022 Smart Structures and Systems, An International Jou Vol.30 No.1

Modal parameters are widely used in bridge damage detection, finite element model (FEM) updating and design optimization. However, the conventional modal identification approaches require large number of sensors, enormous data processing workload, but normally result in mode shapes with low accuracy. This paper proposes a modal identification method of time-varying vehicle-bridge system using a single sensor. Firstly, the essential physical relationship between the instantaneous frequency of the vehicle-bridge system and the bridge mode shapes are derived. Subsequently, based on the synchroextracting transform, the instantaneous frequency of the system is tracked through the dynamic response collected by a single sensor, and further the modal parameters are estimated by using the derived physical relationship. Then numerical and experimental examples are conducted to examine the feasibility and effectiveness of the proposed method. Finally, the modal parameters identified by the proposed method are applied in bridge FEM updating. The results manifest that the proposed method identifies the modal parameters with high accuracy via a single sensor, and can provide reliable data for the FEM updating.

Ring-Opening Block Copolymerization of ε-Caprolactone with L-Lactide Catalyzed by N-Heterocyclic Carbenes: Synthesis, Characteristics, Mechanism

Lifang Zhang,Ning Li,Yan Wang,Jizhe Guo,Junfei Li 한국고분자학회 2014 Macromolecular Research Vol.22 No.6

Block aliphatic polyesters can be useful for medical and pharmaceutical applications. These materials canbe prepared by sequential ring-opening polymerization reactions. In this work, a set of poly(ε-caprolactone)-poly(Llactide)aliphatic polyester AB diblock copolymers and poly(L-lactide)-poly(ε-caprolactone)-poly(L-lactide) aliphaticpolyester ABA triblock copolymers were prepared by consecutive controlled ring-opening polymerizations. Ring-openingpolymerization of ε-caprolactone in the presence of 1-isopropyl-3-(4-methoxyphenyl) imidazol-2-ylidene and ethyleneglycol offered α,ω-dihydroxyl-terminate poly(ε-caprolactone). An array of poly(L-lactide)-poly(ε-caprolactone)-poly(L-lactide) triblock copolymers with controlled molecular weights and narrow molecular weight distributions wassynthesized using the telechelic poly(ε-caprolactone) samples as macroinitiators for the ring-opening polymerizationof L-lactide. 1H NMR and 13C NMR spectral data of copolymers showed the chemical structures without random placement. Meanwhile, the spectral data also indicated that this polymerization mechanism was in agreement with the activatedmonomer mechanism.

Metal Adsorbate-Induced Plasmon Damping in Gold Nanorods: The Difference Between Metals

Pengyu Xu,Xuxing Lu,Junwei Zhao,Yue Li,Sheng Chen,Junfei Xue,Weihui Ou,Song Han,YAPING DING,Weihai Ni 성균관대학교(자연과학캠퍼스) 성균나노과학기술원 2016 NANO Vol.11 No.9

We presented a single particle study on the metal adsorbate-induced plasmon damping in Au nanorods (AuNRs) through adsorbing clusters of different metals including Pt, Au and Ag. AuNRs with different longitudinal surface plasmon resonance (LSPR) wavelength were measured and investigated individually. Linewidth broadening, plasmon shift and reduction of plasmonic resonance of single AuNRs were studied and compared between Pt, Au and Ag adsorbates. The measured linewidths perfectly match the theoretical predictions of the billiard model with increased scattering coefficients resulted from the metal adsorbates. The results indicate that the plasmon damping in case of Ag is significantly weaker than Pt and Au, which can be attributed to longer relaxation time of free electrons in Ag and therefore less loss of the oscillating plasmon electrons. In contrast to the red shift observed from Au and Pt, blue shift of the LSPR is observed in case of Ag. It suggests that plasmonic properties brought by the metal adsorbates can exert dramatic influence on the nanoparticle that is adsorbed with. We believe that our study not only provides important understanding on plasmon damping but pave the road for the fabrication of complex nanostructures with two or more metal elements.

Preparation, Characterization, and Microstructure of Poly(ε-caprolactone–co-2,2-dimethyltrimethylene carbonate) Using Metal-free Organocatalysts

Yan Wang,Jizhe Guo,Lifang Zhang,Junhua Bai,Jifang Niu,Lijuan Jiang,Junfei Li 대한화학회 2015 Bulletin of the Korean Chemical Society Vol.36 No.7

We investigated the random copolymerization of ε-caprolactone and 2,2-dimethyltrimethylene carbonate [poly(CL-co-DTC)] promoted by various imidazolium-based carbenes, including 1-isopropyl-3-p-methoxyphenylimidazol-2-ylidene [Catalyst (1)], 1-isopropy-3-p-methylphenylimidazol-2-ylidene [Catalyst (2)], and 1-methyl-3-p-methoxyphenyl-imidazol-2-ylidene [Catalyst (3)], all of which are new types of unsymmetrical N-heterocyclic carbene catalysts. The reaction was carried out in the presence of benzyl alcohol (BnOH) as an initiator in tetrahydrofuran. By varying the experimental conditions and the monomer feed composition, poly(CL-co-DTC) with high yield and molecular weight was prepared using the binary system Catalyst (1)/BnOH as catalyst/initiator.1H NMR and differential scanning calorimetry (DSC) characterizations verified random structures of the polymer. GPC characterization further showed high molecular weights and narrow molecular weight distribution of the final product.