Joint Deployment and Trajectory Optimization in UAV-Assisted Vehicular Edge Computing Networks

Zhiwei Wu,Zilin Yang,Chao Yang,Jixu Lin,Yi Liu,Xin Chen 한국통신학회 2022 Journal of communications and networks Vol.24 No.1

As the general mobile edge computing (MEC)scheme cannot adequately handle the emergency communicationrequirements in vehicular networks, unmanned aerial vehicle(UAV)-assisted vehicular edge computing networks (VECNs) areenvisioned as the reliable and cost-efficient paradigm for themobility and flexibility of UAVs. UAVs can perform as thetemporary base stations to provide edge services for road vehicleswith heavy traffic. However, it takes a long time and huge energyconsumption for the UAV to fly from the stay charging stationto the mission areas disorderly. In this paper, we design a predispatchUAV-assisted VECNs system to cope with the demandof vehicles in multiple traffic jams. We propose an optimalUAV flight trajectory algorithm based on the traffic situationawareness. The cloud computing center (CCC) server predictsthe real-time traffic conditions, and assigns UAVs to differentmission areas periodically. Then, a flight trajectory optimizationproblem is formulated to minimize the cost of UAVs, while boththe UAV flying and turning energy costs are mainly considered. Inaddition, we propose a deep reinforcement learning(DRL)-basedenergy efficiency autonomous deployment strategy, to obtain theoptimal hovering position of UAV at each assigned mission area. Simulation results demonstrate that our proposed method canobtain an optimal flight path and deployment of UAV with lowerenergy consumption.

Improved performance of polyamide nanofiltration membranes by incorporating reduced glutathione during interfacial polymerization

Zhiwei Jiao,Linjie Zhou,Mengyuan Wu,Kang Gao,Yanlei Su,Zhongyi Jiang 한국화학공학회 2018 Korean Journal of Chemical Engineering Vol.35 No.12

Inspired by the specific amino acid sequence Asn-Pro-Ala (NPA) of water channel aquaporins (AQPs), we fabricated polyamide (PA) nanofiltration (NF) membranes by introducing reduced glutathione (GSH) in interfacial polymerization (IP) method. Fourier transform infrared spectroscopy (ATR-FTIR), X-ray photoelectron spectrometry (XPS), scanning electron microscope (SEM), atomic force microscopy (AFM), zeta potential and static water contact angle measurement were employed to characterize the chemical composition, morphology, electronegativity and hydrophilicity of the NF membranes. The water flux of GSH/PIP-TMC NF membrane reached 32.00 L m2 h1 at 0.2MPa, which was approximately twice than that of pristine PIP-TMC NF membrane when the ratio of GHS to piperazidine (PIP) was 40% during IP process. More water channels were built as GSH was embedded into PA layer. The fabricated NF membranes also took on potent rejection for dyes and Na2SO4. This study presents a simple and facile method to simulate water channels-based biological materials which may find potential application in water treatment.

An Approximate Equivalence Based on process Algebra and Numerical Computation and for Differential Semi-algebraic Hybrid Systems

Zhiwei Zhang,Jinzhao Wu,HouWen Liu 보안공학연구지원센터 2015 International Journal of Hybrid Information Techno Vol.8 No.10

In the paper, approximate ready trace equivalence for differential semi-algebraic hybrid system is proposed. The equivalence can be used to optimize differential semialgebraic hybrid system. The Concept is proposed on the basis of concrete process algebra and numerical analysis theory. In the approximate ready trace equivalence definition, we consider a cut operator for a polynomial and partial approximation for polynomial. Then we get a strict equivalence between two polynomials. Its advantage is that the new polynomial approximation method overcomes the drawback that traditional approximation method is not transitive, which can be used for automatic reasoning. In order to judge the two differential semi-algebraic hybrid system is equivalent, the axiom system for the approximate ready trace equivalence of differential semi-algebraic hybrid system is presented. This axiom system is a complete axiom system.

Numerical Analysis of a Novel Prefabricated Concrete Beam with Double-Grouted Couplers under Static Loading

Zhiwei Lu,Bin Wu,Guoshan Xu 대한토목학회 2023 KSCE Journal of Civil Engineering Vol.27 No.8

This paper provides a nonlinear finite element (FE) investigation of a novel prefabricated beam with double-grouted coupler splices to complement the experimental work and promote its application. FE model considering the surface-to-surface contact behaviour between the prefabricated concrete and grouting mortar is constructed and validated using test data. The validated model is subsequently utilised to conduct a parametric analysis of the most influential factors comprising the diameter and eccentricity of linking rebar and connecting length. Results indicate that the fewer the grouted couplers and the shorter the coupler length, the smaller the effect on the damage pattern and stress distribution of the beam. As the tensile linking rebar diameter increases by 2 mm and 4 mm, the ultimate stress of the linking rebar decreases by 33.4% and 44.0%, respectively, and the maximal crack width in the linking region drops by 85.9% and 97.7%, respectively. Increasing the tension linking rebar diameter significantly reduces the unfavourable influence of linking rebar eccentricity on the linking zone crack width. A decrease in the filler length helps lessen the crack width in the connecting region. Based on the present study, several recommendations for practical engineering use of the developed beam are also presented.

ROBOT MANIPULATOR'S CONTACT TASKS ON UNCERTAIN FLEXIBLE OBJECTS

Jianquing Wu,Zhiwei Luo,Masaki Yamakita,Koji Ito 제어로봇시스템학회 1995 제어로봇시스템학회 국내학술대회 논문집 Vol.1995 No.10

Preparation of Cobalt Ferrite Nanoparticle-Decorated Boron Nitride Nanosheet Flame Retardant and Its Flame Retardancy in Epoxy Resin

Qiaoran Zhang,Zhiwei Li,Xiaohong Li,Laigui Yu,Zhijun Zhang,Zhishen Wu 성균관대학교(자연과학캠퍼스) 성균나노과학기술원 2019 NANO Vol.14 No.5

Boron nitride nanosheet (BNNS) decorated with cobalt ferrite nanoparticle (CFN) to afford CFN-BNNS nanohybrid was prepared via a simple hydrothermal route and was well characterized. Subsequently, the as-prepared CFN-BNNS nanohybrid was incorporated into epoxy resin (EP) with the introduction of a weak rotary magnetic field to achieve order orientation, in order to reduce the fire risk and toxic hazards using enhanced shielding effect of BNNS upon combustion. Findings demonstrate that the CFN-BNNS nanohybrid is composed of CFN nanoparticle uniformly dispersed on BNNS surface. Thermal analysis and cone calorimeter data show that the CFN-BNNS nanofiller among EP matrix contributes to improving the char residues and mechanical properties of EP and reducing its fire risk as well as toxic hazards, especially the ordered one is advantageous over the disordered one in reducing the fire risk and toxic hazard. This is because, on the one hand, the orderly aligned BNNS as the physical barrier can more effectively prevent the transfer and diffusion of oxygen and heat. On the other hand, CFN can catalyze the degradation of EP to afford excessive chars on polymer surface; and it is also liable to decomposition during combustion, thereby generating ferrite species to promote EP degradation as well as cobalt species to enhance the oxidation of CO.

The Effect of miR-361-3p Targeting TRAF6 on Apoptosis of Multiple Myeloma Cells

( Zhen Fan ),( Zhiwei Wu ),( Bo Yang ) 한국미생물생명공학회(구 한국산업미생물학회) 2021 Journal of microbiology and biotechnology Vol.31 No.2

microRNA-361-3p (miR-361-3p) is involved in the carcinogenesis of oral cancer and pancreatic catheter adenocarcinoma, and has anti-carcinogenic effects on non-small cell lung cancer (NSCLC). However, its effect on multiple myeloma (MM) is less reported. Here, we found that upregulating the expression of miR-361-3p inhibited MM cell viability and promoted MM apoptosis. We measured expressions of tumor necrosis factor receptor-associated factor 6 (TRAF6) and miR-361-3p in MM cells and detected the viability, colony formation rate, and apoptosis of MM cells. In addition, we measured expressions of apoptosis-related genes Bcl-2, Bax, and Cleaved caspase-3 (C caspase-3). The binding site between miR-361-3p and TRAF6 was predicted by TargetScan. Our results showed that miR-361-3p was low expressed in the plasma of MM patients and cell lines, while its overexpression inhibited viability and colony formation of MM cells and increased the cell apoptosis. Furthermore, TRAF6, which was predicted to be a target gene of miR-361-3p, was highexpressed in the plasma of patients and cell lines with MM. Rescue experiments demonstrated that the effect of TRAF6 on MM cells was opposite to that of miR-361-3p. Upregulation of miR-361-3p induced apoptosis and inhibited the proliferation of MM cells through targeting TRAF6, suggesting that miR-361-3p might be a potential target for MM therapy.

Robust Finite-horizon l2-l∞ Filtering for Discrete-time Nonhomogeneous Markovian Jump Systems Under Denial-of-service Attacks

Quangui He,Zhiwei Shi,Dingli Wu,Shisheng Fan,Zhengkuan Zhang,Deshuang Liu 제어·로봇·시스템학회 2022 International Journal of Control, Automation, and Vol.20 No.7

The problem of robust finite-horizon l2-l∞ filtering is investigated for a class of discrete-time Markovian jump systems under denial-of-service attacks. The considered dynamic model is more appropriate, on account of polyhedral feature of time-varying transition probabilities. Denial-of-service attack that may jam or compromise the measurement packets on communication channels is assumed as a Bernoulli distributed sequence. Based on stochastic Lyapunov function approach, sufficient criteria corresponding to the error system are established for designing a finite-horizon l2-l∞ filter in the light of linear matrix inequalities. In the end, three illustrative examples are worked out to substantiate the theoretical results.

An Investigation into Water Lubrication Performance of UHMWPE Reinforced with Oriented Polyester Fiber of Different Densities

Yang He,Zhiwei Guo,Wu Ouyang,Chengqing Yuan 한국섬유공학회 2022 Fibers and polymers Vol.23 No.6

Ultra-high molecular weight polyethylene (UHMWPE) has great potential in the field of water-lubricatedbearings. However, water-lubricated bearing made of pure UHMWPE produce significant heat and undergo physical damageunder low speed and heavy load conditions. These performance issues can be improved by reinforcement with fibers thathave excellent complementary properties to UHMWPE. Polyester fibers (PETFs) have high compressive strength and wearresistance, and corresponding oriented-fiber-reinforced-composites (OFRCs) wherein PETF acts as reinforcement show evenbetter mechanical and tribological properties. In this study, the influence of PETF density on UHMWPE was investigated bysystematic testing of different OFRCs. The results show that the optimal fiber density of composites with PETF orientedalong the axial direction was between 1.1 wt% and 2.2 wt%, and that for heavy loads, performance deteriorated withincreasing fiber density. Compared with UHMWPE, OFRCs with the optimal fiber density obtained from this study reducedfriction coefficient by up to 25.93 % and wear volume by 22.67 %, respectively. Considering the low cost, high durability,and relatively low content (<2.2 wt%) necessary for enhanced properties, reinforcement with oriented PETF is a viableapproach to enhance water lubrication performance of UHMWPE.

Sublytic C5b-9 induces glomerular mesangial cell proliferation via ERK1/2-dependent SOX9 phosphorylation and acetylation by enhancing Cyclin D1 in rat Thy-1 nephritis

Xie Mengxiao,Wu Zhijiao,Ying Shuai,Liu Longfei,Zhao Chenhui,Yao Chunlei,Zhang Zhiwei,Luo Can,Wang Wenbo,Zhao Dan,Zhang Jing,Qiu Wen,Qiu Wen 생화학분자생물학회 2021 Experimental and molecular medicine Vol.53 No.-

Glomerular mesangial cell (GMC) proliferation is a histopathological alteration in human mesangioproliferative glomerulonephritis (MsPGN) or in animal models of MsPGN, e.g., the rat Thy‐1 nephritis (Thy-1N) model. Although sublytic C5b-9 assembly on the GMC membrane can trigger cell proliferation, the mechanisms are still undefined. We found that sublytic C5b-9-induced rat GMC proliferation was driven by extracellular signal‐regulated kinase 1/2 (ERK1/2), sry-related HMG-box 9 (SOX9), and Cyclin D1. Here, ERK1/2 phosphorylation was a result of the calcium influx-PKC-α-Raf-MEK1/2 axis activated by sublytic C5b-9, and Cyclin D1 gene transcription was enhanced by ERK1/2-dependent SOX9 binding to the Cyclin D1 promoter (−582 to −238 nt). In addition, ERK1/2 not only interacted with SOX9 in the cell nucleus to mediate its phosphorylation at serine residues 64 (a new site identified by mass spectrometry) and 181 (a known site), but also indirectly induced SOX9 acetylation by elevating the expression of general control non-repressed protein 5 (GCN5), which together resulted in Cyclin D1 synthesis and GMC proliferation. Moreover, our in vivo experiments confirmed that silencing these genes ameliorated the lesions of Thy‐1N rats and reduced SOX9 phosphorylation, acetylation and Cyclin D1 expression. Furthermore, the renal tissue sections of MsPGN patients also showed higher phosphorylation or expression of ERK1/2, SOX9, and Cyclin D1. In summary, these findings suggest that sublytic C5b-9-induced GMC proliferation in rat Thy-1N requires SOX9 phosphorylation and acetylation via enhanced Cyclin D1 gene transcription, which may provide a new insight into human MsPGN pathogenesis.