Study on Multi-scale Unit Commitment Optimization in the Wind-Coal Intensive Power System

Xi YE,Ying QIAO,Zongxiang LU,Yong MIN,Ningbo Wang 대한전기학회 2013 Journal of Electrical Engineering & Technology Vol.8 No.6

Coordinating operation between large-scale wind power and thermal units in multiple time scale is an important problem to keep power balance, especially for the power grids mainly made up of large coal-fired units. The paper proposes a novel operation mode of multi-scale unit commitment (abbr. UC) that includes mid-term UC and day-ahead UC, which can take full advantage of insufficient flexibility and improve wind power accommodation. First, we introduce the concepts of multi-scale UC and then illustrate the benefits of introducing mid-term UC to the wind-coal intensive grid. The paper then formulates the mid-term UC model, proposes operation performance indices and validates the optimal operation mode by simulation cases. Compared with day-ahead UC only, the multi-scale UC mode could reduce the total generation cost and improve the wind power net benefit by decreasing the coal-fired units’ on/off operation. The simulation results also show that the maximum total generation benefit should be pursued rather than the wind power utilization rate in wind-coal intensive system.

Study on Multi-scale Unit Commitment Optimization in the Wind-Coal Intensive Power System

Ye, Xi,Qiao, Ying,Lu, Zongxiang,Min, Yong,Wang, Ningbo The Korean Institute of Electrical Engineers 2013 Journal of Electrical Engineering & Technology Vol.8 No.6

Coordinating operation between large-scale wind power and thermal units in multiple time scale is an important problem to keep power balance, especially for the power grids mainly made up of large coal-fired units. The paper proposes a novel operation mode of multi-scale unit commitment (abbr. UC) that includes mid-term UC and day-ahead UC, which can take full advantage of insufficient flexibility and improve wind power accommodation. First, we introduce the concepts of multi-scale UC and then illustrate the benefits of introducing mid-term UC to the wind-coal intensive grid. The paper then formulates the mid-term UC model, proposes operation performance indices and validates the optimal operation mode by simulation cases. Compared with day-ahead UC only, the multi-scale UC mode could reduce the total generation cost and improve the wind power net benefit by decreasing the coal-fired units' on/off operation. The simulation results also show that the maximum total generation benefit should be pursued rather than the wind power utilization rate in wind-coal intensive system.

SHM-based probabilistic representation of wind properties: Bayesian inference and model optimization

Ye, X.W.,Yuan, L.,Xi, P.S.,Liu, H. Techno-Press 2018 Smart Structures and Systems, An International Jou Vol.21 No.5

The estimated probabilistic model of wind data based on the conventional approach may have high discrepancy compared with the true distribution because of the uncertainty caused by the instrument error and limited monitoring data. A sequential quadratic programming (SQP) algorithm-based finite mixture modeling method has been developed in the companion paper and is conducted to formulate the joint probability density function (PDF) of wind speed and direction using the wind monitoring data of the investigated bridge. The established bivariate model of wind speed and direction only represents the features of available wind monitoring data. To characterize the stochastic properties of the wind parameters with the subsequent wind monitoring data, in this study, Bayesian inference approach considering the uncertainty is proposed to update the wind parameters in the bivariate probabilistic model. The slice sampling algorithm of Markov chain Monte Carlo (MCMC) method is applied to establish the multi-dimensional and complex posterior distribution which is analytically intractable. The numerical simulation examples for univariate and bivariate models are carried out to verify the effectiveness of the proposed method. In addition, the proposed Bayesian inference approach is used to update and optimize the parameters in the bivariate model using the wind monitoring data from the investigated bridge. The results indicate that the proposed Bayesian inference approach is feasible and can be employed to predict the bivariate distribution of wind speed and direction with limited monitoring data.

A Nonparametric Approach for Noisy Point Data Preprocessing

Xi, Yongjian,Duan, Ye,Zhao, Hongkai Society for Computational Design and Engineering 2009 International Journal of CAD/CAM Vol.9 No.1

3D point data acquired from laser scan or stereo vision can be quite noisy. A preprocessing step is often needed before a surface reconstruction algorithm can be applied. In this paper, we propose a nonparametric approach for noisy point data preprocessing. In particular, we proposed an anisotropic kernel based nonparametric density estimation method for outlier removal, and a hill-climbing line search approach for projecting data points onto the real surface boundary. Our approach is simple, robust and efficient. We demonstrate our method on both real and synthetic point datasets.

Invited Mini Review : Stem cell maintenance by manipulating signaling pathways: past, current and future

( Xi Chen ),( Shoudong Ye ),( Qi Long Ying ) 생화학분자생물학회(구 한국생화학분자생물학회) 2015 BMB Reports Vol.48 No.12

Pluripotent stem cells only exist in a narrow window during early embryonic development, whereas multipotent stem cells are abundant throughout embryonic development and are retained in various adult tissues and organs. While pluripotent stem cell lines have been established from several species, including mouse, rat, and human, it is still challenging to establish stable multipotent stem cell lines from embryonic or adult tissues. Based on current knowledge, we anticipate that by manipulating extrinsic and intrinsic signaling pathways, most if not all types of stem cells can be maintained in a long-term culture. In this article, we summarize current culture conditions established for the long-term maintenance of authentic pluripotent and multipotent stem cells and the signaling pathways involved. We also discuss the general principles of stem cell maintenance and propose several strategies on the establishment of novel stem cell lines through manipulation of signaling pathways. [BMB Reports 2015; 48(12): 668-676]

Empirical Study of the Influence of Consumer Relationship Proneness on Customer Loyalty in Service Context

Xi Feng,Mingli Zhang,Jianhua Ye 보안공학연구지원센터 2015 International Journal of u- and e- Service, Scienc Vol.8 No.4

Consumer relationship proneness (CRP) reflects a consumer’s relatively stable and conscious tendency to engage in relationships. This study takes CRP as an important consumer individual trait and examines the influence of CRP on customer loyalty in service environment from perspective of relational benefits (i.e. confidence benefits, social benefits, special treatment benefits). Concept model is proposed to explain the influence. Then SEM (structural equation modeling) is used to analyze the data collected from online survey to test the proposed model. Empirical results show that CRP has direct influence on customer loyalty. The results also show that CRP indirectly relates to customer loyalty via its impact on perceived confidence benefits and social benefits. This study deepens the understanding about the importance of CRP and provides insights into development and implement of customer relationship management and relationship marketing for service enterprises.

Exogenous Glucose Promotes Growth and Pectinase Activity of Bacillus licheniformis DY2 Through Frustrating the TCA Cycle

Xi Du,Donghuang Wang,Di Yin,Yi Guan,Xiuyun Ye 한국생물공학회 2019 Biotechnology and Bioprocess Engineering Vol.24 No.6

Microbial pectinases are important sources due to the ease of production and unique physicochemical properties. Here, DY2, a strain of Bacillus licheniformis, was identified from 14 strains of bacteria as a pectinaseproducing bacterium with good application potential. Optimized carbon sources of submerged fermentation led to the identification of glucose as an ideal carbon source for activity and production of P-DY2, the pectinase produced by DY2. GC-MS based metabolomics was used to explore metabolic mechanisms mediated by glucose, showing the frustrated TCA cycle is necessary to elevate the activity and production of P-DY2. Decreased activity of α-ketoglutaric dehydrogenase and succinate dehydrogenase of DY2 in glucose-treated samples supports the conclusion that P-DY2 production is the TCA cycle-independent. These results reveal a metabolic mechanism of high-activity pectinase mediated by exogenous glucose. These findings highlight the way to understand metabolic mechanisms and promote pectinase yield through metabolomics approach and metabolic modulation, respectively.

Treatment of Periodontal Bone Defects with Stem Cells from Inflammatory Dental Pulp Tissues in Miniature Swine

Ye Li,Xi Nan,Tian-Yu Zhong,Tong Li,Ang Li 한국조직공학과 재생의학회 2019 조직공학과 재생의학 Vol.16 No.2

BACKGROUND: Containing a certain proportion of mesenchymal stem cells, inflammatory dental tissue showed great tissue regeneration potential in recent years. However, whether it is applicable to promote tissue regeneration in vivo remains to be elucidated. Therefore, we evaluated the feasibility of stem cells from inflammatory dental pulp tissues (DPSCs-IPs) to reconstruct periodontal defects in miniature pigs. METHODS: The autologous pig DPSCs-IPs were first cultured, appraised and loaded onto b-tricalcium phosphate (b- TCP). The compounds were then engrafted into an artificially-created periodontal defect. Three months later, the extent of periodontal regeneration was evaluated. Clinical examination, radiological examination and immunohistochemical staining were used to assess periodontal regeneration. RESULTS: The data collectively showed that DPSCs-IPs from miniature pigs expressed moderate to high levels of STRO-1 and CD146 as well as low levels of CD34 and CD45. DPSCs-IPs have osteogentic, adipogenic and chondrogenic differentiation abilities. DPSCs-IPs were engrafted onto b-TCP and regenerated bone to repair periodontal defects by 3 months’ post-surgical reconstruction. CONCLUSION: Autologous DPSCs-IPs may be a feasible means of periodontal regeneration in miniature pigs.

Structural performance monitoring of an urban footbridge

Xi, P.S.,Ye, X.W.,Jin, T.,Chen, B. Techno-Press 2018 Structural monitoring and maintenance Vol.5 No.1

This paper presents the structural performance monitoring of an urban footbridge located in Hangzhou, China. The structural health monitoring (SHM) system is designed and implemented for the footbridge to monitor the structural responses of the footbridge and to ensure the structural safety during the period of operation. The monitoring data of stress and displacement measured by the fiber Bragg grating (FBG)-based sensors installed at the critical locations are used to analyze and assess the operation performance of the footbridge. A linear regression method is applied to separate the temperature effect from the stress monitoring data measured by the FBG-based strain sensors. In addition, the static vertical displacement of the footbridge measured by the FBG-based hydrostatic level gauges are presented and compared with the dynamic displacement remotely measured by a machine vision-based measurement system. Based on the examination of the monitored stress and displacement data, the structural safety evaluation is executed in combination with the defined condition index.

Vortex induced vibration and its controlling of long span Cross-Rope Suspension transmission line with tension insulator

Xi Tu,Ye Wu,Zhengliang Li,Zhisong Wang 국제구조공학회 2021 Structural Engineering and Mechanics, An Int'l Jou Vol.78 No.1

Long span cross-rope suspension structure is an innovative structural system evolved from typical Cross-Rope Suspension (CRS) guyed tower, a type of supporting system with short span suspension cable supporting overhead power transmission lines. In mountainous areas, the span length of suspension cable was designed to be extended to hundreds or over one thousand meters, which is applicable for crossing deep valleys. Vortex Induced Vibration (VIV) of overhead power transmission lines was considered to be one of the major factors of its fatigue and service life. In this paper, VIV and its controlling by Stockbridge damper for long span CRS was discussed. Firstly, energy balance method and finite element method for assessing VIV of CRS were presented. An approach of establishing FE model of long span CRS structure with dampers was introduced. The effect of Stockbridge damper for overall vibration of CRS was compared in both theoretical and numerical approaches. Results indicated that vibration characteristics of conductor in long span CRS compared with traditional tower-line system. Secondly, analysis on long span CRS including Stockbridge damper showed additional dampers installed were essential for controlling maximum dynamic bending stresses of conductors at both ends. Moreover, factors, including configuration and mass of Stockbridge damper, span length of suspension cable and conductor and number of spans of conductor, were assessed for further discussion on VIV controlling of long span CRS.