Phasor Estimation for Grid Power Monitoring: Least Square vs. Linear Kalman Filter

International audienc

Detection and mapping of homologous and homoeologous segments in homoeologous groups of allotetraploid cotton by BAC-FISH

<p>Abstract</p> <p>Background</p> <p>Cotton, as an allopolyploid species, contains homoeologous A and D subgenomes. The study of the homoeologous (duplicated) segments or chromosomes can facilitate insight into the evolutionary process of polyploidy and the development of genomic resources. Fluorescence <it>in situ </it>hybridization (FISH) using bacterial artificial chromosome (BAC) clones as probes has commonly been used to provide a reliable cytological technique for chromosome identification. In polyploids, it also presents a useful approach for identification and localization of duplicated segments. Here, two types of BACs that contained the duplicated segments were isolated and analyzed in tetraploid cotton by FISH.</p> <p>Results</p> <p>Homologous and homoeologous BACs were isolated by way of SSR marker-based selection and then used to develop BAC-FISH probes. Duplicated segments in homoeologous chromosomes were detected by FISH. The FISH and related linkage map results followed known reinforced the relationships of homoeologous chromosomes in allotetraploid cotton, and presented a useful approach for isolation of homoeologous loci or segments and for mapping of monomorphic loci. It is very important to find that the large duplicated segments (homologous BACs) do exist between homoeologous chromosomes, so the shot-gun approach for genome sequencing was unavailable for tetraploid cotton. However, without doubt, it will contain more information and promote the research for duplicated segments as well as the genome evolution in cotton.</p> <p>Conclusion</p> <p>These findings and the analysis method by BAC-FISH demonstrated the powerful nature and wide use for the genome and genome evolutionary researches in cotton and other polyploidy species.</p

An Ensemble Empirical Mode Decomposition Approach for Voltage Sag Detection in a Smart Grid Context

International audienceSmart grids have become a focal point in renewable energy source researches. Sustainability and viability of distributed grids are highly dependent on the reduction of the operational and maintenance costs. The most efficient way of reducing these costs would be to continuously monitor the condition of these systems. This allows for early detection of the power quality degeneration, and facilitating a proactive response, prevent a fault ride-through the renewable energy conversion system, minimizing downtime, and maximizing productivity. This paper provides then the assessments of an advanced signal processing technique, namely the ensemble empirical mode decomposition, using the instantaneous power for voltage sags detection in smart grids

Aggressive maneuver oriented robust actuator fault estimation of a 3-DOF helicopter prototype considering measurement noises

This paper presents a robust actuator fault estimation strategy design for a 3-DOF helicopter prototype which can be adapted to aggressive maneuvers. First, considering large pitch angle condition during flight, nonlinear coupling characteristic of the helicopter system is exploited. As the pitch angle can be measured in real time, a polytopic linear parameter-varying (LPV) model is developed for the helicopter system. Furthermore, considering measurement noises in the actual helicopter system, the dynamical model of helicopter system is modified accordingly. Then, based on the modified polytopic LPV model, a robust unknown input observer (UIO) is developed for the helicopter system to realize actuator fault estimation, in which both measurement noises and large pitch angle are considered. Robust performance of proposed fault estimation approach is guaranteed by using energy-to-energy strategy. And the observer gains are calculated by using linear matrix inequalities. Finally, based on a 3-DOF helicopter prototype, both simulations and experiments are conducted. The effects of measurement noises and large pitch angle on the fault estimation performance are sufficiently demonstrated. And effectiveness as well as advantages of the proposed observer is verified by using comparative analysis

Performance Analysis of an EEMD-based Hilbert Huang Transform as a Bearing Failure Detector in Wind Turbines

International audienceSustainability and viability of wind farms are highly dependent on the reduction of the operational and maintenance costs. The most efficient way of reducing these costs would be to continuously monitor the condition of these systems. This allows for early detection of the degeneration of the generator health, facilitating a proactive response, minimizing downtime, and maximizing productivity. This paper deals then with the assessment of a demodulation technique for bearing failure detection through wind turbines generator stator current. The proposed technique is based on a modified version of the Hilbert Huang transform. In this version, the use of the EEMD algorithm allows overcoming the well-known mixed mode

Smart Grid Voltage Sag Detection using Instantaneous Features Extraction

International audienceSmart grids have initiated a radical reappraisal of distribution networks function where the integration of renewable energy sources, load demand control, and effective use of the network are indexed as the most important keys for smart grid expansion and deployment regardless each country policies. One of the most efficient ways of effective use of these grids would be to continuously monitor their conditions. This allows for early detection of power quality degeneration facilitating therefore a proactive response, prevent a fault ride-through the renewable power sources, minimizing downtime, and maximizing productivity. In this smart grid context, this paper proposes the evaluation and comparison of advanced signal processing tools, namely the Hilbert transform and the ensemble empirical mode decomposition method for the detection of voltage sags as they are the most commonly encountered power quality disturbances

A preliminary analysis of genome structure and composition in Gossypium hirsutum

<p>Abstract</p> <p>Background</p> <p>Upland cotton has the highest yield, and accounts for > 95% of world cotton production. Decoding upland cotton genomes will undoubtedly provide the ultimate reference and resource for structural, functional, and evolutionary studies of the species. Here, we employed GeneTrek and BAC tagging information approaches to predict the general composition and structure of the allotetraploid cotton genome.</p> <p>Results</p> <p>142 BAC sequences from <it>Gossypium hirsutum </it>cv. Maxxa were downloaded <url>http://www.ncbi.nlm.nih.gov</url> and confirmed. These BAC sequence analysis revealed that the tetraploid cotton genome contains over 70,000 candidate genes with duplicated gene copies in homoeologous A- and D-subgenome regions. Gene distribution is uneven, with gene-rich and gene-free regions of the genome. Twenty-one percent of the 142 BACs lacked genes. BAC gene density ranged from 0 to 33.2 per 100 kb, whereas most gene islands contained only one gene with an average of 1.5 genes per island. Retro-elements were found to be a major component, first an enriched LTR/gypsy and second LTR/copia. Most LTR retrotransposons were truncated and in nested structures. In addition, 166 polymorphic loci amplified with SSRs developed from 70 BAC clones were tagged on our backbone genetic map. Seventy-five percent (125/166) of the polymorphic loci were tagged on the D-subgenome. By comprehensively analyzing the molecular size of amplified products among tetraploid <it>G. hirsutum </it>cv. Maxxa, acc. TM-1, and <it>G. barbadense </it>cv. Hai7124, and diploid <it>G. herbaceum </it>var. <it>africanum </it>and <it>G. raimondii</it>, 37 BACs, 12 from the A- and 25 from the D-subgenome, were further anchored to their corresponding subgenome chromosomes. After a large amount of genes sequence comparison from different subgenome BACs, the result showed that introns might have no contribution to different subgenome size in <it>Gossypium</it>.</p> <p>Conclusion</p> <p>This study provides us with the first glimpse of cotton genome complexity and serves as a foundation for tetraploid cotton whole genomesequencing in the future.</p

How daily supervisor abuse and coworker support affect daily work engagement

The purpose of this study was to explore the dynamic and intervention mechanisms of daily abusive experience affecting daily work engagement. Drawing on conservation of resources (COR) theory, we examine the effect of daily abusive supervision on daily work engagement through daily negative emotions from the resource consumption perspective, and the moderation effect of coworker support from the resource provision perspective. Using a daily diary approach and based on a sample of 73 employees for 5 consecutive days in China. The results reveal that daily abusive supervision has a significant negative effect on daily work engagement, daily negative emotions mediate this relationship, and coworker support had a cross-level moderating effect between daily abusive supervision and daily negative emotions. Our study shows ways to boost employees’ daily work engagement and especially ways buffer the negative effect of abused experience on work engagement

Exploring the Applicability of Building Energy Performance Certification Systems in Underground Stations in China

To improve the energy efficiency of underground metro stations, and in view of the absence of a comprehensive energy performance evaluation system for underground stations, this study introduced building Energy Performance Certification (EPC) tools into underground stations and conducted a comparative analysis of their applicability. The findings indicated that due to the unique characteristics of underground stations, China’s current EPC system was inapplicable to them. Specifically, (1) for basic items, although evaluation methods were available, due to the limited energy use data for the statistical method, the self-reference method was preferred, but its calculation encountered issues with missing reference values; (2) for prescribed items, the emphasis should be placed on the energy efficiency requirements of energy use systems rather than those of the thermal performance of envelopes; (3) for alternative items, the energy recovery measures related to the heat dissipation of trains and the piston wind should be addressed. Furthermore, a case study was conducted for verification of the proposed energy evaluation method, and the EPC system was updated based on the results of the comparison. The authors hope that this study will help improve China’s energy evaluation methods for underground stations and serve as a reference for expanding the EPC system to include public transportation buildings

Characteristics and assessment of the electricity consumption of metro systems: A case study of Tianjin, China

Owing to the complexity of metros, the energy consumption characteristics of metro systems exhibit variability and the energy‐saving management of the systems encounters challenges. To encapsulate the essential characteristics of energy usage and to objectively assess the energy performance of metro systems, this study presents a generalized framework and applies it to a case study conducted in Tianjin. The study also employs correlation analysis to investigate the applicability of the indicators relevant to ridership. The results indicate that the monthly traction electricity consumption exhibits slight variation, while station electricity usage demonstrates substantial fluctuation with seasonal changes. For Tianjin Metro, the passenger factor hardly shows any effect on the electricity use of metro lines. The median value of traction electricity use is approximately 2.0 kWh/(car‐km) and that of the average annual station electricity use of underground lines ranges from 95 to 155 kWh/m2. The emission from the traction sector is 12.2 kgCO2/(vehicle‐km) and from the station sector is 118.6 kgCO2/m2. The study also identifies the energy‐intensive lines of the Tianjin Metro and compares the energy utilization among various global metro systems. The authors hope that this study can help shed light on the assessment of the energy status of metro systems and serve as a source of information for other City‐Metros to implement energy‐saving management