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Qingfei Xu,Xinyu Yang 한국항공우주학회 2020 International Journal of Aeronautical and Space Sc Vol.21 No.4
AFDX (Avionics Full Duplex switched Ethernet) standardized as ARINC 664 is chosen as the backbone network for distributed real-time avionics systems as it offers high throughput and does not require global clock synchronization. A deterministic upper bound of the end-to-end transmission delays for packets of each flow should be guaranteed to ensure the network performance. In this paper, we focus on the forward end-to-end delay analysis (FA). This approach iteratively estimates the maximum backlog (amount of the pending packets) in the switch output port along the transmission path so that the worst-case end-to-end transmission delay can be computed and the network performance can be evaluated. Recent research demonstrates this approach is pessimistic (overestimated). This paper presents an optimization which considers the serialization effect of packets transmitted through the same physical link. We provide a comparative analysis on both sample network configurations and real industrial systems. The experiments show that by considering the serialization effect the forward end-to-end delay analysis can remove the pessimism in the analysis of end-to-end transmission delay. The evaluation of network performance can be improved. Then a discussion on the potential optimism (underestimation) is presented.
( Qingfei Yin ) 경남대학교 극동문제연구소 2018 ASIAN PERSPECTIVE Vol.42 No.4
The intense and volatile relations between China and Vietnam in the dyadic world of the Cold War have drawn scholarly attention to the strategic concerns of Beijing and Hanoi. In this article I move the level of analysis down to the border space where the peoples of the two countries meet on a daily basis. I examine the tug-of-war between the states and smuggling networks on the Sino-Vietnamese border during the second half of the twentieth century and its implications for the present-day bilateral relationship. I highlight that the existence of the historically nonstate space was a security concern for modernizing states in Asia during and after the Cold War, which is an understudied aspect of China’s relations with Vietnam and with its Asian neighbors more broadly. The border issue between China and its Asian neighbors concerned not only territorial disputes and demarcation but also the establishment of state authority in marginal societies.
Qingfei Xu,Xinyu Yang 한국항공우주학회 2019 International Journal of Aeronautical and Space Sc Vol.20 No.2
With growing avionics applications, information transmission has been increasing in real-time systems of airplanes; AFDX (Avionics Full Duplex Switched Ethernet) standardized as ARINC 664 is widely used in avionics transmission systems for its high speed and duplex characteristics. For safety–critical systems such as flight control system, the time limit of information transmission should be deterministic and it is used to evaluate the performance of the real-time systems. Network Calculus is a powerful approach used to estimate the performance of avionics real-time system by calculating the possible longest transmission time, but the performance analysis is usually pessimistic for the pessimistic assumptions in the computation. Grouping strategy can improve that analysis by considering serialization effect of information transmitting from the same physical link, but the analysis of system performance is still pessimistic. In this paper, we explore the pessimism in Network Calculus and Grouping strategy, and then propose a Rate-constrained grouping strategy to improve the analysis of system performance. The experiments on both sample avionics system and real industrial system confirm the validity and applicability of the performance analysis.
Cao Qingfei,Ma Jiaji,Li Weitao,Hong Peng,Shen Tong,Tong Ming 한국유전학회 2023 Genes & Genomics Vol.45 No.1
Background Guanine nucleotide-binding protein 2 (GNBP2) is a GTPase that has critical roles in host immunity and some types of cancer, but its function in clear cell renal cell carcinoma (ccRCC) is not fully understood. Objective This work explored the role of GNBP2 in ccRCC progression and the underlying molecular mechanism. Methods Two public human cancer databases TNMplot and TISIDB were employed to analyze the expression pattern of GNBP2 during ccRCC progression and the correlation between GNBP2 expression and clinical features of ccRCC patients. GNBP2 functions in ccRCC cells were determined by EdU staining, flow cytometry, scratch wound assay, transwell assay, and xenograft model. Gene expression was evaluated using qPCR, Western blot, immunofluorescence staining, and immunohistochemical staining. Results GNBP2 expression was significantly elevated in ccRCC tissues and increased gradually with the increasing tumor grades. Patients with higher GNBP2 expression had shorter overall survival times. Knockdown of GNBP2 suppressed tumor cell proliferation and cell cycle progression and reduced the capability of migration and invasion, while GNBP2 overexpression exhibited protumor effects. GNBP2 silencing by RNA interference significantly inhibited the tumor growth of tumor-bearing nude mice and decreased the proliferation marker Ki67. Mechanistically, GNBP2 downregulation suppressed the STAT3 signaling transduction, as it reduced the phosphorylation of STAT3 and modulated the expression of the target genes, including c-Myc, MMP2, N-cadherin, and E-cadherin. Conclusion These findings reveal that GNBP2 promotes ccRCC progression by regulating STAT3 signaling transduction, indicating that GNBP2 might be a promising molecular target for ccRCC therapy.
Effect of smoothing on robust chaos.
Deshpande, Amogh,Chen, Qingfei,Wang, Yan,Lai, Ying-Cheng,Do, Younghae Published by the American Physical Society through 2010 Physical review. E, Statistical, nonlinear, and so Vol.82 No.2
<P>In piecewise-smooth dynamical systems, situations can arise where the asymptotic attractors of the system in an open parameter interval are all chaotic (e.g., no periodic windows). This is the phenomenon of robust chaos. Previous works have established that robust chaos can occur through the mechanism of border-collision bifurcation, where border is the phase-space region where discontinuities in the derivatives of the dynamical equations occur. We investigate the effect of smoothing on robust chaos and find that periodic windows can arise when a small amount of smoothness is present. We introduce a parameter of smoothing and find that the measure of the periodic windows in the parameter space scales linearly with the parameter, regardless of the details of the smoothing function. Numerical support and a heuristic theory are provided to establish the scaling relation. Experimental evidence of periodic windows in a supposedly piecewise linear dynamical system, which has been implemented as an electronic circuit, is also provided.</P>
Nonstructural Influence Factors of Dynamic Load Allowance for Concrete Beam Bridges
Chenguang Liu,Zonglin Wang,Qingfei Gao 대한토목학회 2019 KSCE JOURNAL OF CIVIL ENGINEERING Vol.23 No.5
Studies show that nonstructural parameters, such as pavement conditions or load patterns, have greater influences on the dynamic load allowance (DLA) of bridges than structural parameters. For pavement roughness effects, the values of DLA caused by roughness profiles are calculated by a self-compiled program. The results showed that the values of DLA are discrete even if they are caused by roughness profiles that belong to the same power spectral density (PSD) grade. The PSD grade method for pavement conditions has limitations when it is used in the analysis of DLA. Statistical analysis was also carried out on these DLA results. The statistical analysis indicated that the values of DLA followed a normal distribution when they were excited by roughness profiles that belong to the same grade. For the influence of vehicle string loads on DLA, an improved optimization approach based on a genetic algorithm for the largest DLA is presented. A new method is used to calculate the fitness value in the genetic algorithm (GA) method, which could substantially reduce calculation time. The new approach is able to obtain the most unfavorable arrangement of the vehicle string and estimate the largest DLA caused by it.
Molecular Dynamics Simulation of supercritical spray at micro & nano scale
( Zhang Yunxiao ),( Fu Qingfei ),( Mo Chaojie ),( Yang Lijun ) 한국액체미립화학회 2017 한국액체미립화학회 학술강연회 논문집 Vol.2017 No.-
The supercritical jets have many applications in many fields ranging from aerospace propulsion to chemical engineering. However, there is still lack of relevant theoretical research on the characteristics of supercritical fluids, and also lack of deep understanding of the destabilization mechanism of supercritical jets. Molecular dynamics method, which has been quite mature, can simulate extreme harsh physical conditions and exceptionally complex geometric model. The simulation process spontaneously contains all the physical effects. Therefore, the purpose of this paper is to study the characteristics and destabilization mechanism of supercritical jets from the microcosmic perspective using molecular dynamics method. Firstly, the molecular dynamics simulation of EOS (Equation of State) of liquid nitrogen was carried out. The influence of different simulation parameters on the simulation results was analyzed and then compared with the theoretical results. Four conditions were selected to study the influences of different time step, total simulation steps and truncation distance on the simulation results. The results show that the truncation distance has a great influence on the simulation precision, the time step and the total simulation steps have no significant impact on the EOS of liquid nitrogen. The results are in good agreement with the SRK (Soave-Redlich-Kwong) equation, which show the correctness of the simulation of supercritical fluids using molecular dynamics method. Secondly, the molecular dynamics simulation of supercritical nitrogen jet was carried out at different conditions. The supercritical jets ejected into a supercritical environment and a subcritical environment, respectively. Through the analysis of the results, the distribution of jet velocity, density, temperature and other jet characteristics was obtained. The interface was determined where concentration of supercritical fluid component reached 50% because the supercritical jet has no obvious vapor-liquid interface. Stable analysis of the results was performed and the disturbance growth rate of the supercritical shear layer at different conditions was obtained. Finally, the growth rate achieved by processing the results of molecular simulation was compared to the results by the linear stability analysis.
Pharmacokinetics and Biodistribution of Surface Modification Polymeric Nanoparticles
Mingxing Liu,Huifang Li,Guoan Luo,Qingfei Liu,Yiming Wang 대한약학회 2008 Archives of Pharmacal Research Vol.31 No.4
The objective of this study is to investigate the pharmacokinetics and biodistribution of free breviscapine (BVP) and coated BVP-loaded poly (D, L-lactic acid) nanoparticles (BVP-PLANPs) in rats after i.v. administration. Coated BVP-PLA-NPs were prepared by the spontaneous emulsification solvent diffusion method and characterized. The BVP content in the NPs, the biological samples and in vitro release was measured by the high-performance liquid chromatography (HPLC). The mean sizes of coated BVP-PLA-NPs were 177 and 319 nm with a narrow distribution and smooth sphere shapes, entrapment efficiency of 86.9% and 93.1%, respectively. Drug release profiles in phosphate buffer and plasma exhibited a biphasic release phenomenon. After i.v. administration of free BVP and NPs suspensions in rats, area under plasma concentration-time curve and elimination t1/2 were increased 9.3-fold and 10.9-fold for 177 nm of NPs, and 4.4-fold and 17.1-fold for 319 nm of NPs compared with that of free BVP, respectively. NPs were mainly distributed in liver, spleen, heart and brain. In addition, NPs could penetrate blood brain barrier (BBB) and the particle size had some effect on pharmacokinetics and biodistribution. Coated BVP-PLA-NPs could effectively avoid the capture by the reticuloendothelial system and prolong the half-life of BVP. Moreover, these NPs could penetrate BBB and enhance the accumulation of BVP in brain.
Environmental Effects and Output-Only Model Identification of Continuous Bridge Response
Chuang Chen,Mosbeh R. Kaloop,Qingfei Gao,Zonglin Wang 대한토목학회 2015 KSCE JOURNAL OF CIVIL ENGINEERING Vol.19 No.7
Studying the response of bridge due to temperature effects is the main aim of this paper. The Fu-Sui bridge is constructed on a hard environmental effect region in China. To evaluate and assessment the behavior of this bridge, a finite element model and Structural Health Monitoring System (SHM) are used. In addition, the output only model identification is used to assess the thermal response and displacement of bridge. The results of the finite element and monitoring system reveal to that the behavior of the bridge after the first working year is safe, but over a long time period the low temperatures will have an effect on the behavior of the bridge, especially for the upper girder monitoring points. The thermal response and displacement output of the model used conforms with the SHM measurements. Also, the models calculated can be used to detect the bridge behavior in future time monitoring.