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.

Excessive fastener spacing of high speed railway ballastless track at beam end by the construction errors and environment temperature

Moyan Zhang,Hong Xiao,Jiaqi Wang,Shuwei Fang,Ziqing Jiang 대한기계학회 2022 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.36 No.8

Excessive fastener spacing, which results from construction errors (the bridge construction error and the track layout error) and environment temperature, is a possible safety risk for train and track structure. To address this problem, this paper selected a CRTSIII ballastless track-bridge section as the engineering case, and established a thermal-mechanical trackbridge coupling model. The maximum fastener spacing was calculated based on the model, and the dynamic and static characteristics of train and track under the different fastener spacing were compared. The results show that under the combination of construction errors and ambient temperature, the most unfavorable fastener spacing is 755 mm; with the increase in fastener spacing, the longitudinal resistance of fasteners first reaches the limit in the static safety indexes; the rail vertical dynamic displacement first reaches the limit in the dynamic safety indexes. Therefore, maximum fastener spacing of CRTSIII ballastless track structure depends on railway operation and maintenance, train speed and local environment.

Analysis and research on dynamic characteristics of 3D braided composite two-stage reducer case

Weiliang Zhang,Xupeng Wang,Xiaomin Ji,Xinyao Tang,Fengfeng Liu,Shuwei Liu,Mingjun Liu,Xiao-Long Gao 대한기계학회 2023 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.37 No.6

Based on the analysis of the movement rule of 3D five-way braided yarn, the 3D five-way braided case model is divided into three parts: base, case bottom plate and case wall. According to the characteristics of each part, the braiding and forming principle of a 3D five-way composite case was analyzed. Under the assumption of ignoring the influence of friction, bearing and other factors on the system, the differential equations of motion of the two-stage gear transmission system with case were established. The two-stage gear transmission system was numerically analyzed by Euler method, and the influence of dimensionless meshing frequency, clearance, case mass and damping on the dynamic characteristics of the transmission system was studied. After that, high and low frequency disturbance was applied to the input case. The research shows that the damping ratio of the composite case increases and the low frequency attenuation is accelerated due to the decrease of the case mass, so the composite case has better shock resistance to low frequency interference.

Functional analysis of a homologue of the FLORICAULA/LEAFY gene in litchi (Litchi chinensis Sonn.) revealing its significance in early flowering process

Feng Ding,Shuwei Zhang,Houbin Chen,Hongxiang Peng,Jiang Lu,Xinhua He,Jiechun Pan 한국유전학회 2018 Genes & Genomics Vol.40 No.12

Litchi (Litchi chinensis Sonn.) is an important subtropical fruit crop with high commercial value due to its high nutritional values and favorable tastes. However, irregular bearing attributed to unstable flowering is a major ongoing problem for litchi producers. Previous studies indicate that low-temperature is a key factor in litchi floral induction. In order to reveal the genetic and molecular mechanisms underlying the reproductive process in litchi, we had analyzed the transcriptome of buds before and after low-temperature induction using RNA-seq technology. A key flower bud differentiation associated gene, a homologue of FLORICAULA/LEAFY, was identified and named LcLFY (GenBank Accession No. KF008435). The cDNA sequence of LcLFY encodes a putative protein of 388 amino acids. To gain insight into the role of LcLFY, the temporal expression level of this gene was measured by real-time RT-PCR. LcLFY was highly expressed in flower buds and its expression correlated with the floral developmental stage. Heterologous expression of LcLFY in transgenic tobacco plants induced precocious flowering. Meantime, we investigated the sub-cellular localization of LcLFY. The LcLFY-Green fluorescent protein (GFP) fusion protein was found in the nucleus. The results suggest that LcLFY plays a pivotal role as a transcription factor in controlling the transition to flowering and in the development of floral organs in litchi.

A Study on Aero-Engine Direct Thrust Control with Nonlinear Model Predictive Control Based on Deep Neural Network

Qiangang Zheng,Shuwei Pang,Haibo Zhang,Zhongzhi Hu 한국항공우주학회 2019 International Journal of Aeronautical and Space Sc Vol.20 No.4

For enhancing engine response ability, a novel nonlinear model predictive control (NMPC) method for aero-engine direct thrust control is proposed. The control objective of the proposed method is the thrust instead of the measurable parameters. The online-sliding window deep neural network (OL-SW-DNN) is proposed as predictive model. The OL-SW-DNN adopts deep-learning structure to increase the model accuracy and selects the nearest point data of certain length as training data which will reduce the sensitivity for the noise of training data. The direct thrust simulations of the popular NMPC based on extended Kalman filler (EKF) and the proposed one are conducted, respectively. The simulations demonstrate that compared with the popular NMPC, the proposed NMPC decreases the acceleration time by 0.425 s and increases response speed about 1.14 times.

The improvement effect of surfactants on hydrogenation at condition containing water for Cu/SiO2 catalysts

Zheng Chen,Xueying Zhao,Shuwei Wei,Dengfeng Wang,Xuelan Zhang,Jianfeng Shan 한국화학공학회 2022 Korean Journal of Chemical Engineering Vol.39 No.11

In the industrial production, water exists inevitably into feed stocks in the form of impurity, and it can produce a negative effect in the hydrogenation reaction due to the preferential adsorption of water on active sites. Here, the surfactants (polyvinylpyrrolidone, poloxamer, polyethylene glycol and hexadecyl trimethyl ammonium bromide) are used to improve physicochemical property of Cu/SiO2 catalysts, so that Cu/SiO2 catalysts had a good hydrogenation performance at condition containing water. The appropriate addition amount of surfactants in the catalyst preparation process effectively hindered the agglomeration of copper species by steric configuration and repulsion effect between Cu2+ and positive ionizable, which brought about high copper dispersion and small particle size. Meanwhile, the decomposition of surfactants produced many pores during calcination, resulting in the increased of specific surface area and average pore diameter. These advantages provided more chances for reactants to touch active sites due to spatial restriction and the increase of the number of active sites, so that the negative effects of water can be counteracted. The conversion of Cu/SiO2 catalysts, that the surfactants was added in the catalyst preparation process, increased 60% to 200% at reaction condition containing water.

Gene Expression Profiling in the Pituitary Gland of Laying Period and Ceased Period Huoyan Geese

Luan, Xinhong,Cao, Zhongzan,Xu, Wen,Gao, Ming,Wang, Laiyou,Zhang, Shuwei Asian Australasian Association of Animal Productio 2013 Animal Bioscience Vol.26 No.7

Huoyan goose is a Chinese local breed famous for its higher laying performance, but the problems of variety degeneration have emerged recently, especially a decrease in the number of eggs laid. In order to better understand the molecular mechanism that underlies egg laying in Huoyan geese, gene profiles in the pituitary gland of Huoyan geese taken during the laying period and ceased period were investigated using the suppression subtractive hybridization (SSH) method. Total RNA was extracted from pituitary glands of ceased period and laying period geese. The cDNA in the pituitary glands of ceased geese was subtracted from the cDNA in the pituitary glands of laying geese (forward subtraction); the reverse subtraction was also performed. After sequencing and annotation, a total of 30 and 24 up and down-regulated genes were obtained from the forward and reverse SSH libraries, respectively. These genes mostly related to biosynthetic process, cellular nitrogen compound metabolic process, transport, cell differentiation, cellular protein modification process, signal transduction, small molecule metabolic process. Furthermore, eleven genes were selected for further analyses by quantitative real-time PCR (qRT-PCR). The qRT-PCR results for the most part were consistent with the SSH results. Among these genes, Synaptotagmin-1 (SYT1) and Stathmin-2 (STMN2) were substantially over-expressed in laying period compared to ceased period. These results could serve as an important reference for elucidating the molecular mechanism of higher laying performance in Huoyan geese.

Clinical and Genetic Features of Brainstem Glioma in Adults: A Report of 50 Cases in a Single Center

Chunhui Zhou,Hao Zhao,Fan Yang,Luokai Huangfu,Chao Dong,Shuwei Wang,Jianning Zhang 대한신경과학회 2021 Journal of Clinical Neurology Vol.17 No.2

Background and Purpose Brainstem gliomas (BSGs) in adults are rare brain tumors with dismal outcomes. The aim of this study was to determine the clinical and genetic features in a series of BSGs and their association with the prognosis. Methods Fifty patients who underwent a stereotactic biopsy between January 2016 and April 2018 at a single institution were collected. Data on clinicopathological characteristics were analyzed and factors associated with patient survival were identified using a Cox regression model. Results The median age at diagnosis was 55.5 years, and 62% of the patients were male. Glioblastoma (44%) accounted for the largest proportion of BSGs, and oligodendroglioma (2 of 50) was rarely encountered. The IDH mutation (6 of 44) occurred infrequently in astrocytomas, and IDH-mutant tumors harbored both ATRX loss and MGMT promoter methylation at a relatively low level. Wild-type IDH astrocytomas were identified as having high rates of 1p/19q codeletion (5 of 38) and loss of heterozygosity 1p (8 of 38) or 19q (8 of 38) only. In diffuse midline glioma H3K27M mutant, MGMT promoter methylation occurred in three of four cases. Patients were offered radiotherapy and/or concurrent/adjuvant temozolomide chemotherapy, and their median survival time was 13 months. Multivariate analysis revealed that a low tumor grade, absence of tumor enhancement, duration of symptoms ≥3 months, Karnofsky performance status ≥70, and ATRX loss conferred a survival advantage. Conclusions Adult BSGs showed different molecular genetic characteristics, but also resembled supratentorial gliomas in their clinical features associated with oncological outcomes.

Ginsenoside Rb1 attenuates methamphetamine (METH)-induced neurotoxicity through the NR2B/ERK/CREB/BDNF signalings in vitro and in vivo models

Genmeng Yang,Juan Li,Yanxia Peng,Baoyu Shen,Yuanyuan Li,Liu Liu,Chan Wang,Yue Xu,Shucheng Lin,Shuwei Zhang,Yi Tan,Huijie Zhang,Xiaofeng Zeng,Qi Li,Gang Lu 고려인삼학회 2022 Journal of Ginseng Research Vol.46 No.3

This study investigates the effects of ginsenoside Rb1 (GsRb1) on methamphetamine (METH)-induced toxicity in SH-SY5Y neuroblastoma cells and METH-induced conditioned place preference (CPP)in adult Sprague-Dawley rats. It also examines whether GsRb1 can regulate these effects through theNR2B/ERK/CREB/BDNF signaling pathways. Methods: SH-SY5Y cells were pretreated with GsRb1 (20 mM and 40 mM) for 1 h, followed by METHtreatment (2 mM) for 24 h. Rats were treated with METH (2 mg/kg) or saline on alternating days for 10days to allow CPP to be examined. GsRb1 (5, 10, and 20 mg/kg) was injected intraperitoneally 1 h beforeMETH or saline. Western blot was used to examine the protein expression of NR2B, ERK, P-ERK, CREB, PCREB, and BDNF in the SH-SY5Y cells and the rats' hippocampus, nucleus accumbens (NAc), and prefrontal cortex (PFC). Results: METH dose-dependently reduced the viability of SH-SY5Y cells. Pretreatment of cells with 40mM of GsRb1 increased cell viability and reduced the expression of METH-induced NR2B, p-ERK, p-CREBand BDNF. GsRb1 also attenuated the expression of METH CPP in a dose-dependent manner in rats. Further, GsRb1 dose-dependently reduced the expression of METH-induced NR2B, p-ERK, p-CREB, andBDNF in the PFC, hippocampus, and NAc of rats. Conclusion: GsRb1 regulated METH-induced neurotoxicity in vitro and METH-induced CPP through theNR2B/ERK/CREB/BDNF regulatory pathway. GsRb1 could be a therapeutic target for treating METHinduced neurotoxicity or METH addiction.

Corrigendum to "Ginsenoside Rb1 attenuates methamphetamine (METH)-induced neurotoxicity through the NR2B/ERK/CREB/BDNF signalings in vitro and in vivo models"

Xiaofeng Zeng,Qi Li,Gang Lu,Genmeng Yang,Juan Li,Yanxia Peng,Baoyu Shen,Yuanyuan Li,Liu Liu,Chan Wang,Yue Xu,Shucheng Lin,Shuwei Zhang,Yi Tan,Huijie Zhang The Korean Society of Ginseng 2023 Journal of Ginseng Research Vol.47 No.2