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The Top-K QoS-aware Paths Discovery for Source Routing in SDN
( Xi Chen ),( Junlei Wu ),( Tao Wu ) 한국인터넷정보학회 2018 KSII Transactions on Internet and Information Syst Vol.12 No.6
Source routing is the routing scheme that arranges the whole path from source to target at the origin node that may suit the requirements from the upper layer applications’ perspective. The centralized control in SDN (Software-Defined Networking) networks enables the awareness of the global topology at the controller. Therefore, augmented source routing schemes can be designed to achieve various purposes. This paper proposes a source routing scheme that conducts the top-K QoS-aware paths discovery in SDN. First, the novel non-invasive QoS over LLDP scheme is designed to collect QoS information based on LLDP in a piggyback fashion. Then, variations of the KSP (K Shortest Paths) algorithm are derived to find the unconstrained/constrained top-K ranked paths with regard to individual/overall path costs, reflecting the Quality of Service. The experiment results show that the proposed scheme can efficiently collect the QoS information and find the top-K paths. Also, the performance of our scheme is applicable in QoS-sensitive application scenarios compared with previous works.
Wu, Xi,Jiang, Ping,Chen, Bo-Lin,Xiong, Hua-Chuan Journal of International Conference on Electrical 2012 Journal of international Conference on Electrical Vol.1 No.2
The Test Signal Method is adopted to analyze the impact of thyristor controlled series capacitor (TCSC) on sub-synchronous oscillation. The results show that the simulation system takes the risk of Sub-synchronous Oscillation (SSO) while the TCSC is operating in the capacitive region. A supplementary excitation damping controller (SEDC) is used to mitigate SSO caused by the TCSC. A new optimization method which is aimed for optimal phase compensation is proposed. This method is realized by using the particle swarm optimization (PSO) algorithm. The simulation results show that the SEDC designed by this method has superior suitability, and that the secure operation scope of the TCSC is greatly increased.
The role of WRKY47 gene in regulating selenium tolerance in Arabidopsis thaliana
Xi Wu,Manzhi Tao,Yun Meng,Xiangyu Zhu,Liangwen Qian,Alia Shah,Wei Wang,Shuqing Cao 한국식물생명공학회 2020 Plant biotechnology reports Vol.14 No.1
Selenium stress has a serious impact on the growth of plants. However, the available understanding on the mechanism of Se stress response is still insufficient. In this study, we found that the WRKY47 gene plays an important role in maintaining Se homeostasis and tolerance in Arabidopsis thaliana. Expression of WRKY47 is induced by Se stress. The wrky47 mutants are sensitive to Se stress, and this sensitivity is associated with a decrease in the transcription levels of Se-detoxify genes HMT1 and HMT3. Surprisingly, the WRKY47-overexpression lines also showed increased sensitivity to Se stress and had increased Se content; this correlates to an increase in the transcription level of Se-uptake gene PHT1;4 but not Se-detoxify genes HMT1 and HMT3. Our results suggest that gain- and loss-of-function mutations in WRKY47 enhance the sensitivity of A. thaliana plants to Se stress through different mechanisms.
Xi-Wu Pan,Lei Han,Yu-Hua Zhang,Dong-Fang Chen,Henrik Toft Simonsen 한국식물생명공학회 2015 Plant biotechnology reports Vol.9 No.3
The moss Physcomitrella patens was engineered to produce the diterpenoid sclareol, an important precursor for the synthesis of ambergris substitutes for the perfume industry. The best total yield of sclareol was 2.84 mg/g dry weight (2.28 mg/l culture) obtained after 18 days of cultivation in liquid media (extracted from both media and cell pellet). The two active sclareol synthase genes were integrated in a random fashion, and linked with the ribosomal skip 2A under the control of the CaMV 35S promoter. We conclude that moss can produce sclareol and utilize the ribosomal skip 2A. In addition, we observed growth impairment in all our sclareol-producing lines and moss lines knocked out in the endogenous diterpene synthase (copalyl/kaurene synthase—PpCPS/KS). A RT-PCR study, with ubiquitin as the best reference gene, showed that there was a down-regulation of the transcription of the terpenoid biosynthetic genes in the PpCPS/KS knock out moss. This down-regulation was recovered by the introduction of the two sclareol synthases, suggesting that the regulation of the general terpenoid biosynthesis is very flexible and can be amended in future biotechnological engineering.
Design-Oriented Stability of Outer Voltage Loop in Capacitor Current Controlled Buck Converters
Xi Zhang,Zhongwei Zhang,Bocheng Bao,Han Bao,Zhimin Wu,Kaiwen Yao,Jing Wu 전력전자학회 2019 JOURNAL OF POWER ELECTRONICS Vol.19 No.4
Due to the inherent feedforward of load current, capacitor current (CC) control shows a fast transient response that makes itsuitable for the power supplies used in various portable electronic devices. However, considering the effect of the outer voltageloop, the stable range of the duty-cycle is significantly diminished in CC controlled buck converters. To investigate the stabilityeffect of the outer voltage loop on buck converters, a CC controlled buck converter with a proportion-integral (PI) compensatoris taken as an example, and its second-order discrete-time model is established. Based on this model, the instability caused by theduty-cycle is discussed with consideration of the outer voltage loop. Then the dynamical effects of the feedback gain of the PIcompensator and the equivalent series resistance (ESR) of the output capacitor on the CC controlled buck converter with a PIcompensator are studied. Furthermore, the design-oriented closed-loop stability criterion is derived. Finally, PSIM simulationsand experimental results are supplied to verify the theoretical analyses.
Xi-Wu Gong,Xiao-Qiong Wang,You-Rong Li,Chun-Mei Wu 대한기계학회 2015 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.29 No.7
We present a novel coupled organic Rankine cycle (CORC) system driven by the low-grade waste heat, which couples a transcriticalorganic Rankine cycle with a subcritical organic Rankine cycle. Based on classical thermodynamic theory, a detailed performance analysison the novel CORC system was performed. The results show that the pressure ratio of the expander is decreased in the CORC and theselection of the working fluids becomes more flexible and abundant. With the increase of the pinch point temperature difference of theinternal heat exchanger, the net power output and thermal efficiency of the CORC all decrease. With the increase of the critical temperatureof the working fluid, the system performance of the CORC is improved. The net power output and thermal efficiency of the CORCwith isentropic working fluids are higher than those with dry working fluids.
Design-Oriented Stability of Outer Voltage Loop in Capacitor Current Controlled Buck Converters
Zhang, Xi,Zhang, Zhongwei,Bao, Bocheng,Bao, Han,Wu, Zhimin,Yao, Kaiwen,Wu, Jing The Korean Institute of Power Electronics 2019 JOURNAL OF POWER ELECTRONICS Vol.19 No.4
Due to the inherent feedforward of load current, capacitor current (CC) control shows a fast transient response that makes it suitable for the power supplies used in various portable electronic devices. However, considering the effect of the outer voltage loop, the stable range of the duty-cycle is significantly diminished in CC controlled buck converters. To investigate the stability effect of the outer voltage loop on buck converters, a CC controlled buck converter with a proportion-integral (PI) compensator is taken as an example, and its second-order discrete-time model is established. Based on this model, the instability caused by the duty-cycle is discussed with consideration of the outer voltage loop. Then the dynamical effects of the feedback gain of the PI compensator and the equivalent series resistance (ESR) of the output capacitor on the CC controlled buck converter with a PI compensator are studied. Furthermore, the design-oriented closed-loop stability criterion is derived. Finally, PSIM simulations and experimental results are supplied to verify the theoretical analyses.
Xing-Xi Gao,Jun-Hua Wu,Da-Hua Shi,Yun-Xi Chen,Jiang-Tao Cui,Yu-Rong Wang,Chun-Ping Jiang 대한약학회 2012 Archives of Pharmacal Research Vol.35 No.8
The aim of this study was to investigate the effects of tectorigenin on chemically induced liver fibrosis in rats. Liver fibrosis was induced in rats with carbon tetrachloride, a diet high in fat, cholesterol and alcohol in the drinking water. Our results indicate that tectorigenin treatment significantly inhibited the increases in the activities of alanine aminotransferase (ALT),aspartate aminotransferase (AST) and the increases in the serum levels of hyaluronate (HA), laminin (LN) and procollagen III N-terminal peptide (PIIIP); tectorigenin treatment also significantly inhibited the increases in the amount of collagen in the livers of the fibrogenic rats. Chemically induced liver fibrosis caused a drop in the serum albumin concentration and a decrease in the ratio of albumin to globulin (A/G). Tectorigenin caused a remarkable increase at a dose of 30 mg/kg, but only a slight increase at the lower doses. Tectorigenin was also able to inhibit the increase in the liver lipid peroxidation (LPO), as well as the decrease in the activities of liver superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px), caused by liver fibrosis. In addition, we present a related metabolic profile determined, using a 1H NMR spectroscopy and multivariate pattern recognition techniques. The results were consistent with the pathological examination, liver function analysis and liver fibrosis marker analysis. Furthermore, tectorigenin does not cause acute toxicity.