Modelling and Simulating the Spatio-Temporal Correlations of Clustered Wind Power Using Copula

Zhang, Ning,Kang, Chongqing,Xu, Qianyao,Jiang, Changming,Chen, Zhixu,Liu, Jun The Korean Institute of Electrical Engineers 2013 Journal of Electrical Engineering & Technology Vol.8 No.6

Modelling and simulating the wind power intermittent behaviour are the basis of the planning and scheduling studies concerning wind power integration. The wind power outputs are evidently correlated in space and time and bring challenges in characterizing their behaviour. This paper provides a methodology to model and simulate the clustered wind power considering its spatio-temporal correlations using the theory of copula. The sampling approach captures the complex spatio-temporal connections among the wind farms by employing a conditional density function calculated using multidimensional copula function. The empirical study of real wind power measurement shows how the wind power outputs are correlated and how these correlations affect the overall uncertainty of clustered wind power output. The case study validates the simulation technique by comparing the simulated results with the real measurements.

The Protective Roles of S-adenosylmethionine Decarboxylase (SAMDC) Gene in Melon Resistance to Powdery Mildew Infection

Changming Liu,Xiaoling Li,Ruiping Yang,Yanling Mo,Yongqi Wang,Feng Xian,Xian Zhang,Fei Wang 한국원예학회 2014 Horticulture, Environment, and Biotechnology Vol.55 No.6

Powdery mildew caused by Podosphaera xanthii (P. xanthii) is one of important diseases in melon. Wehave previously investigated the differential gene expression in the incompatible P. xanthii-melon interactions andidentified one EST containing homologous sequences to S-adenosylmethionine decarboxylase (SAMDC) cDNA. Giventhis, SAMDC gene of Cucumis melo was cloned and designated as CmSAMDC in this study. It was 1,095 bp longand encoded a 364-amino acid peptide with a molecular mass of 40 kD. By sequence analyzing, the deducedCmSAMDC protein was shown to have two conserved regions of a putative proenzyme cleavage site and a PESTdomain. In addition, the expressions of CmSAMDC in the resistant melon materials increased more sharply than inthe susceptible the melon materials, and the higher polyamines (PAs) and hydrogen peroxide (H2O2) contents inresistant melon materials were found as well, which were accompanied by up-regulation of the stress-responsive defenseenzyme activities. Over-expression of CmSAMDC in Arabidopsis resulted in greatly reduced pathogen infection in theinoculated leaves of transgenic lines, enhanced resistance to powdery mildew, and the enhanced resistance appearedto be associated with pathogen-induced cell death. Taken together, our results suggested that CmSAMDC and perhapsits orthologous genes might be involved in responses of plants to biotrophic pathogens.

Research on Comparative Analysis of Regional Logistics Information Platform Operation Mode Based on Cloud Computing

Changming Li,Xiangdong Zhang,Lijie Li 보안공학연구지원센터 2014 International Journal of Future Generation Communi Vol.7 No.2

Finite-Time Nonlinear Disturbance Observer Based Discretized Integral Sliding Mode Control for PMSM Drives

Zheng, Changming,Zhang, Jiasheng The Korean Institute of Power Electronics 2018 JOURNAL OF POWER ELECTRONICS Vol.18 No.4

To deal with the operation performance degradation of permanent magnet synchronous machine (PMSM) drives with uncertainties and unmodeled dynamics, this paper presents a finite-time nonlinear disturbance observer (FTNDO) based discretized integral sliding mode (DISM) composite control scheme. Based on the reaching-law approach, a DISM speed controller featuring a superior dynamic quality and global robustness against disturbances is constructed. This controller can avoid the reaching phase and overlarge control action. In addition, a sliding mode differentiator based FTNDO is devised and extended to the discrete-time domain for disturbance estimation. The attractive features of the FTNDO are that it can provide a finite-time converging estimation and alleviate the chattering effect in conventional sliding mode observers, while retaining robustness to parameter variations. By feeding the estimate forward to the pre-stage DISM controller, both disturbances and chattering can be significantly suppressed. Moreover, considering the estimation error of a FTNDO caused by discrete sampling, a stability analysis of the composite controller is discussed. Experimental results validate the superiority of the presented scheme.

Modelling and Simulating the Spatio-Temporal Correlations of Clustered Wind Power Using Copula

Ning Zhang,Chongqing Kang,Qianyao Xu,Changming Jiang,Zhixu Chen,Jun Liu 대한전기학회 2013 Journal of Electrical Engineering & Technology Vol.8 No.6

Modelling and simulating the wind power intermittent behaviour are the basis of the planning and scheduling studies concerning wind power integration. The wind power outputs are evidently correlated in space and time and bring challenges in characterizing their behaviour. This paper provides a methodology to model and simulate the clustered wind power considering its spatiotemporal correlations using the theory of copula. The sampling approach captures the complex spatiotemporal connections among the wind farms by employing a conditional density function calculated using multidimensional copula function. The empirical study of real wind power measurement shows how the wind power outputs are correlated and how these correlations affect the overall uncertainty of clustered wind power output. The case study validates the simulation technique by comparing the simulated results with the real measurements.

Disparity-based Error Concealment for Stereoscopic Images with Superpixel Segmentation

( Yizhang Zhang ),( Guijin Tang ),( Xiaohua Liu ),( Changming Sun ) 한국인터넷정보학회 2018 KSII Transactions on Internet and Information Syst Vol.12 No.9

To solve the problem of transmission errors in stereoscopic images, this paper proposes a novel error concealment (EC) method using superpixel segmentation and adaptive disparity selection (SSADS). Our algorithm consists of two steps. The first step is disparity estimation for each pixel in a reference image. In this step, the numbers of superpixel segmentation labels of stereoscopic images are used as a new constraint for disparity matching to reduce the effect of mismatching. The second step is disparity selection for a lost block. In this step, a strategy based on boundary smoothness is proposed to adaptively select the optimal disparity which is used for error concealment. Experimental results demonstrate that compared with other methods, the proposed method has significant advantages in both objective and subjective quality assessment.

Decentralized control strategy for storage systems in islanded microgrids

Liwei Zhang,Lei Dai,Changming Zhao 전력전자학회 2021 JOURNAL OF POWER ELECTRONICS Vol.21 No.12

This paper presents a decentralized control strategy for the distributed storage (DS) systems of the islanded microgrid composed of distributed generations (DGs) and DSs. Each of the DSs consists of a bidirectional DC-DC converter cascaded with a three-phase inverter. Control strategies for DSs and DGs are based on droop control. The line frequency of the point of common coupling (PCC) is an agent to regulate the active power of the DS. Due to the power mismatch among the supplies and load demands of DGs, the frequency controller of the DS generates its active power reference. In addition, the frequency deviation caused by droop control can be reduced. Reactive load power is almost equally shared by all of the constituent units. Therefore, the DS works by charging or discharging the energy storage devices. Simulation and experimental results are provided to verify the effectiveness of the proposed control strategy.

Efficacy of combination of endo-xylanase and xylan-debranching enzymes in improving cereal bran utilization in piglet diet

Wang Weiwei,Zheng Dawen,Zhang Zhenzhen,Ye Hui,Cao Qingyun,Zhang Changming,Dong Zemin,Feng Dingyuan,Zuo Jianjun 아세아·태평양축산학회 2022 Animal Bioscience Vol.35 No.11

Objective: This study was aimed to explore the efficacy of combination of endo-xylanase (Xyn) and xylan-debranching enzymes (arabinofuranosidase, Afd and feruloyl esterase, FE) in improving utilization of bran in piglet diet. Methods: In vitro experiments were firstly conducted to examine the enzymological properties of Xyn, Afd, and FE, concurrent with their effect on degradation of arabinoxylan (Abx) in bran. In vivo experiment was then implemented by allocating two hundred and seventy 35-d-old postweaning piglets into 3 groups (6 replicates/group), which received bran-containing diet supplemented with Xyn (1,600 U/kg) or its combination with Afd (0.8 U/kg) and FE (4 U/kg) or without enzyme. Results: Both Xyn, Afd, and FE are relatively stable against the changes in temperature and pH value. Combining Xyn with Afd and FE had a superiority (p<0.05) over Xyn alone and its combination with Afd or FE in promoting (p<0.05) degradation of Abx in different brans. Combined treatment with Xyn, Afd, and FE was more beneficial than Xyn alone to induce increasing trends (p<0.10) of average daily gain, final body weight and feed efficiency of piglets fed bran-containing diet. Moreover, combination of Xyn, Afd, and FE showed advantages (p<0.05) over Xyn alone in causing reductions (p<0.05) in diarrhea rate and cecal pH value, concurrent with increases (p<0.05) in cecal and colonic acetic acid and total volatile fatty acid concentrations, as well as cecal butyric acid concentration of piglets fed brancontaining diet. Conclusion: Combining Xyn with Afd and FE was more beneficial than Xyn alone in promoting degradation of Abx in bran, along with growth performance and intestinal volatile fatty acid profile of piglets received bran-containing diet. Thereby, combination of Xyn, Afd, and FE had a superior efficacy relative to Xyn alone in improving application of cereal bran in piglet diet. Objective: This study was aimed to explore the efficacy of combination of endo-xylanase (Xyn) and xylan-debranching enzymes (arabinofuranosidase, Afd and feruloyl esterase, FE) in improving utilization of bran in piglet diet.Methods: <i>In vitro</i> experiments were firstly conducted to examine the enzymological properties of Xyn, Afd, and FE, concurrent with their effect on degradation of arabinoxylan (Abx) in bran. <i>In vivo</i> experiment was then implemented by allocating two hundred and seventy 35-d-old postweaning piglets into 3 groups (6 replicates/group), which received bran-containing diet supplemented with Xyn (1,600 U/kg) or its combination with Afd (0.8 U/kg) and FE (4 U/kg) or without enzyme.Results: Both Xyn, Afd, and FE are relatively stable against the changes in temperature and pH value. Combining Xyn with Afd and FE had a superiority (p<0.05) over Xyn alone and its combination with Afd or FE in promoting (p<0.05) degradation of Abx in different brans. Combined treatment with Xyn, Afd, and FE was more beneficial than Xyn alone to induce increasing trends (p<0.10) of average daily gain, final body weight and feed efficiency of piglets fed bran-containing diet. Moreover, combination of Xyn, Afd, and FE showed advantages (p<0.05) over Xyn alone in causing reductions (p<0.05) in diarrhea rate and cecal pH value, concurrent with increases (p<0.05) in cecal and colonic acetic acid and total volatile fatty acid concentrations, as well as cecal butyric acid concentration of piglets fed bran-containing diet.Conclusion: Combining Xyn with Afd and FE was more beneficial than Xyn alone in promoting degradation of Abx in bran, along with growth performance and intestinal volatile fatty acid profile of piglets received bran-containing diet. Thereby, combination of Xyn, Afd, and FE had a superior efficacy relative to Xyn alone in improving application of cereal bran in piglet diet.

Antioxidant Mechanism and Lipid Peroxidation Patterns in Leaves and Petals of Marigold in Response to Drought Stress

Zhiguo Tian,Fei Wang,Wene Zhang,Changming Liu,Xiuming Zhao 한국원예학회 2012 Horticulture, Environment, and Biotechnology Vol.53 No.3

In this study, malondialdehyde (MDA), relative conductivity (RC), superoxide anion (O2・-), hydrogen peroxide (H2O2), superoxide dismutase (SOD), peroxidase (POD), catalase (CAT), ascorbate peroxidase (APX) as well as ascorbic acid (AsA), glutation (GSH) and carotenoid (Car) were analyzed in plants under drought condition to investigate the enzymatic and non-enzymatic antioxidant defense mechanisms of leaves and petals, respectively. Two different drought resistance marigold cultivars (Tagetes erecta L. cv. Chokdee and Tagetes erecta L. cv. Discovery)treated with 6-day drought stress were used at early flowering stage. Results indicated that drought treatment increased MDA, RC, O2・- and H2O2 contents in the two cultivars, especially in drought-sensitive cultivar ‘Discovery’. In contrast,‘Chokdee’ had higher level antioxidative enzyme activities and more non-enzymatic antioxidants than those in ‘Discovery’. SOD, POD, CAT, APX activities and non-enzymatic antioxidants (GSH and AsA) in the leaves and petals were increased at the beginning treatment, and decreased later. The activity of CAT in leaves and petals, APX in petals and AsA in petals on day 6 after treatment were lower than those in control, while Car in the two cultivars decreased consistently during drought stress treatment. In addition, all the antioxidant enzyme activities in the leaves were higher than those in petals, but AsA and GSH were accumulated at lower levels in leaves than those in petals of the both cultivars. Furthermore, significant linear relationships were found between antioxidative enzymes and reactive oxygen species (ROS), as well as in non-enzymatic antioxidants and ROS. In conclusion, drought tolerance of ‘Chokdee’ was correlated with eliminating the O2・- and H2O2 and maintaining lower lipid peroxidation as well as higher membrane stability by increasing activities of antioxidative enzymes and the amount of non-enzymatic antioxidants. Furthermore, different drought response mechanisms were involved in leaves and petals of marigold under drought stress.