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Magnetic resonance imaging ancillary features used in Liver Imaging Reporting and Data System:An illustrative review 被引量:3
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作者 David Campos-Correia Joao Cruz +2 位作者 António P Matos Filipa Figueiredo Miguel Ramalho 《World Journal of Radiology》 CAS 2018年第2期9-23,共15页
Hepatocellular carcinoma (HCC) usually develops in the setting of chronic liver disease. In the adequate clinical context, both multiphasic contrast-enhanced CT and magnetic resonance imaging are non-invasive modaliti... Hepatocellular carcinoma (HCC) usually develops in the setting of chronic liver disease. In the adequate clinical context, both multiphasic contrast-enhanced CT and magnetic resonance imaging are non-invasive modalities that allow accurate diagnosis and staging of HCC, although the latter demonstrates greater sensitivity and specificity. Imaging criteria for HCC diagnosis rely on hemodynamic features such as hyperenhancement in the arterial phase and washout in the portal or equilibrium phase. However, imaging performance drops considerably for small (< 20 mm) nodules because their tendency to exhibit atypical enhancement patterns. In order to improve accuracy in the diagnosis and staging of HCC, particularly in cases of atypical nodules, ancillary features, i.e., imaging characteristics that modify the likelihood of HCC, have been described and incorporated into clinical reports, especially in Liver Imaging Reporting and Data System. In this paper, ancillary imaging features will be reviewed and illustrated. 展开更多
关键词 HEPATOCELLULAR carcinoma ancillary FEATURES Magnetic resonance IMAGING LIVER IMAGING REPORTING and Data system CIRRHOSIS LIVER
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Integrating TM and Ancillary Geographical Data with Classification Trees for Land Cover Classification of Marsh Area 被引量:14
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作者 NA Xiaodong ZHANG Shuqing +3 位作者 ZHANG Huaiqing LI Xiaofeng YU Huan LIU Chunyue 《Chinese Geographical Science》 SCIE CSCD 2009年第2期177-185,共9页
The main objective of this research is to determine the capacity of land cover classification combining spec- tral and textural features of Landsat TM imagery with ancillary geographical data in wetlands of the Sanjia... The main objective of this research is to determine the capacity of land cover classification combining spec- tral and textural features of Landsat TM imagery with ancillary geographical data in wetlands of the Sanjiang Plain, Heilongjiang Province, China. Semi-variograms and Z-test value were calculated to assess the separability of grey-level co-occurrence texture measures to maximize the difference between land cover types. The degree of spatial autocorrelation showed that window sizes of 3×3 pixels and 11×11 pixels were most appropriate for Landsat TM im- age texture calculations. The texture analysis showed that co-occurrence entropy, dissimilarity, and variance texture measures, derived from the Landsat TM spectrum bands and vegetation indices provided the most significant statistical differentiation between land cover types. Subsequently, a Classification and Regression Tree (CART) algorithm was applied to three different combinations of predictors: 1) TM imagery alone (TM-only); 2) TM imagery plus image texture (TM+TXT model); and 3) all predictors including TM imagery, image texture and additional ancillary GIS in- formation (TM+TXT+GIS model). Compared with traditional Maximum Likelihood Classification (MLC) supervised classification, three classification trees predictive models reduced the overall error rate significantly. Image texture measures and ancillary geographical variables depressed the speckle noise effectively and reduced classification error rate of marsh obviously. For classification trees model making use of all available predictors, omission error rate was 12.90% and commission error rate was 10.99% for marsh. The developed method is portable, relatively easy to im- plement and should be applicable in other settings and over larger extents. 展开更多
关键词 land cover classification classification trees Landsat TM ancillary geographical data MARSH
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Evaluation index system of shared energy storage market towards renewable energy accommodation scenario:A China’s Qinghai province context 被引量:16
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作者 Baomin Fang Weiqiang Qiu +3 位作者 Maochun Wang Wei Zhou Zhenzhi Lin Fushuan Wen 《Global Energy Interconnection》 EI CAS CSCD 2022年第1期77-95,共19页
With the ever-increased installed capacity of renewable energy generation units in a power system,the so-called shared energy storage(SES),a novel business model under the umbrella of the shared economy principle,has ... With the ever-increased installed capacity of renewable energy generation units in a power system,the so-called shared energy storage(SES),a novel business model under the umbrella of the shared economy principle,has the potential to play an essential role in the accommodation of renewable energy generation.However,unified evaluation standards and methods,which can help decision-makers analyze the performance of the SES market,are still not available.In this paper,an evaluation index system of the SES market is designed based on the trading rules of China’s Qinghai province and the structure-conduct-performance(SCP)analytical model.Moreover,the definition and characteristics of the indices,which can show the performance of the SES market from different perspectives,are given.Furthermore,the ideal cases are presented as the evaluation benchmark based on the development expectation of the SES market,and the analytic hierarchy process(AHP)and the technique for order preference by similarity to an ideal solution(TOPSIS)are applied to evaluate the SES market comprehensively.Finally,a case study based on actual data of the SES trading pilot project in Qinghai shows that the evaluation index system can reflect the operation status,existing problems and influencing factors of the SES market. 展开更多
关键词 Shared energy storage(SES) Renewable energy accommodation scenario Evaluation index system ancillary service market
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Endoscopic ultrasound guided fine needle aspiration and useful ancillary methods 被引量:6
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作者 Mario Tadic Tajana Stoos-Veic Rajko Kusec 《World Journal of Gastroenterology》 SCIE CAS 2014年第39期14292-14300,共9页
The role of endoscopic ultrasound(EUS) in evaluating pancreatic pathology has been well documented from the beginning of its clinical use. High spatial resolution and the close proximity to the evaluated organs within... The role of endoscopic ultrasound(EUS) in evaluating pancreatic pathology has been well documented from the beginning of its clinical use. High spatial resolution and the close proximity to the evaluated organs within the mediastinum and abdominal cavity allow detection of small focal lesions and precise tissue acquisition from suspected lesions within the reach of this method. Fine needle aspiration(FNA) is considered of additional value to EUS and is performed to obtain tissue diagnosis. Tissue acquisition from suspected lesions for cytological or histological analysis allows, not only the differentiation between malignant and non-malignant lesions, but, in most cases, also the accurate distinction between the various types of malignant lesions. It is well documented that the best results are achieved only if an adequate sample is obtained for further analysis, if the material is processed in an appropriate way, and if adequate ancillary methods are performed. This is a multi-step process and could be quite a challenge in some cases. In this article, we discuss the technical aspects of tissue acquisition by EUS-guided-FNA(EUS-FNA), as well as the role of an on-site cytopathologist, various means of specimen processing, and the selection of the appropriate ancillary method for providing an accurate tissue diagnosis and maximizing the yield of this method. The main goal of this review is to alert endosonographers, not only to the different possibilities of tissue acquisition, namely EUS-FNA, but also to bring to their attention the importance of proper sample processing in the evaluation of various lesions in the gastrointestinal tract and other accessible organs. All aspects of tissue acquisition(needles, suction, use of stylet, complications, etc.) have been well discussed lately. Adequate tissue samples enable comprehensive diagnoses, which answer the main clinical questions, thus enabling targeted therapy. 展开更多
关键词 Endoscopic ultrasound Endoscopic ultrasound-guided fine needle aspiration Endoscopic ultrasound-guided tissue acquisition Fine needle aspiration cytology ancillary studies Molecular testing Flow cytometry immunophenotyping
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Experiences of the Electricity System Operator Incentive Scheme in Great Britain 被引量:1
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作者 Guilherme Luiz Susteras Dorel Soares Ramos 《Energy and Power Engineering》 2012年第4期218-225,共8页
National Grid is the electricity system operator in Great Britain and has an unique feature in so far as it is one of the world’s few for-profit system operators. In addition, the commercially orientation of the Brit... National Grid is the electricity system operator in Great Britain and has an unique feature in so far as it is one of the world’s few for-profit system operators. In addition, the commercially orientation of the British market rules means that nearly every action taken by National Grid to operate the system has a cost associated to it. Based on those factors and in order to encourage National Grid to seek continuous improvements and drive for efficient and economic system operation, the regulator (Ofgem) offers an incentive scheme, whereby a target is agreed annually and any savings in relation to this target are shared between consumers and National Grid in the form of a profit. It is in National Grid’s best interest to have mechanisms to mitigate the impacts of volatility in the costs it faces as system operator so that it can implement cost saving actions without the risk of windfall losses (or gains) arising from sudden changes in uncontrollable drivers. The purpose of this paper is to share the experiences of National Grid in the operation of Great Britain's electricity system, with a special interest on the mechanisms created to manage the associated costs in response to the incentive scheme. It does so by describing the market operation in Great Britain and the costs drivers impacting National Grid’s system operation and illustrating the steps recently taken by National Grid to propose volatility mitigation mechanisms. It concludes with the rationale and expected results from the latest proposals as consulted with the industry for introduction in the incentive scheme starting on 1st April 2011. It is worth noting that with this work, the authors wish to both share the experience with other system operators and regulators in the world, as well as give British market participants an insight on the inner workings of National Grid. 展开更多
关键词 Power system system Operation ancillary Services Wholesale Electricity Market
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Combining Landsat-8 spectral bands with ancillary variables for land cover classification in mountainous terrains of northern Pakistan
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作者 Arif UR REHMAN Sami ULLAH +3 位作者 Muhammad SHAFIQUE Muhammad Sadiq KHAN Muhammad Tariq BADSHAH LIU Qi-jing 《Journal of Mountain Science》 SCIE CSCD 2021年第9期2388-2401,共14页
Landsat-8 spectral values have been used to map the earth’s surface information for decades.However,forest types and other land-use/land-cover(LULC)in the mountain terrains exist on different altitudes and climatic c... Landsat-8 spectral values have been used to map the earth’s surface information for decades.However,forest types and other land-use/land-cover(LULC)in the mountain terrains exist on different altitudes and climatic conditions.Hence,spectral information alone cannot be sufficient to accurately classify the forest types and other LULC,especially in high mountain complex.In this study,the suitability of Landsat-8 spectral bands and ancillary variables to discriminate forest types,and other LULC,using random forest(RF)classification algorithm for the Hindu Kush mountain ranges of northern Pakistan,was discussed.After prior-examination(multicollinearity)of spectral bands and ancillary variables,three out of six spectral bands and five out of eight ancillary variables were selected with threshold correlation coefficients r2<0.7.The selected datasets were stepwise stacked together and six Input Datasets(ID)were created.The first ID-1 includes only the Surface Reflectance(SR)of spectral bands,and then in each ID,the extra one ancillary variable including Normalized Difference Vegetation Index(NDVI),Normalized Difference Water Index(NDWI),Normalized Difference Snow Index(NDSI),Land Surface Temperature(LST),and Digital Elevation Model(DEM)was added.We found an overall accuracy(OA)=72.8%and kappa coefficient(KC)=61.9%for the classification of forest types,and other LULC classes by using the only SR bands of Landsat-8.The OA=81.5%and KC=73.7%was improved by the addition of NDVI,NDWI,and NDSI to the spectral bands of Landsat-8.However,the addition of LST and DEM further increased the OA,and Kappa coefficient(KC)by 87.5%and 82.6%,respectively.This indicates that ancillary variables play an important role in the classification,especially in the mountain terrain,and should be adopted in addition to spectral bands.The output of the study will be useful for the protection and conservation,analysis,climate change research,and other mountains forest-related management information. 展开更多
关键词 Forest types Landuse Landcover Landsat-8 Random forest ancillary variables Mountain environment
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Webgis-Based Telecommunication Resource Management Auxiliary Wiring System
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作者 Jin LUO XiaoFang ZU Guo CHEN 《Journal of Geographic Information System》 2010年第1期19-22,共4页
This paper introduces the necessity and superiority of auxiliary wiring WEBGIS, as well as system implementation difficulties and countermeasures. Then explained the general concept of auxiliary wiring systems, data i... This paper introduces the necessity and superiority of auxiliary wiring WEBGIS, as well as system implementation difficulties and countermeasures. Then explained the general concept of auxiliary wiring systems, data interface response, and finally introduced the system wiring switchover function, and gave an example. 展开更多
关键词 WEBGIS ancillary WIRING systems flow CHART
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Effect of Anionic Ancillary Ligands on Terpyridine Based Coordination Polymers:Synthesis,Crystal Structure and Fluorescence Property
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作者 张四方 李军 《Chinese Journal of Structural Chemistry》 SCIE CAS CSCD 2016年第5期811-817,共7页
By using different anionic ancillary ligands, two new coordination polymers, [Cd(L)I_2]_n(1) and {[Cd(L)_2(1,4-bdc)]·H_2O}_n(2)(L = 2,4,6-tris(4-pyridyl)pyridine, 1,4-H_2bdc = benzene-1,4-dicarboxyli... By using different anionic ancillary ligands, two new coordination polymers, [Cd(L)I_2]_n(1) and {[Cd(L)_2(1,4-bdc)]·H_2O}_n(2)(L = 2,4,6-tris(4-pyridyl)pyridine, 1,4-H_2bdc = benzene-1,4-dicarboxylic acid), have been synthesized under hydrothermal conditions. Compound 1 crystallizes in monoclinic, space group C2/c with a = 11.625(2), b = 13.871(3), c = 13.676(3) A, β = 108.11(3)°, V = 2096.0(7)A3, D_c = 2.144 g/cm^3, C_(20)H_(14)I_2N_4Cd, M_r = 676.55, F(000) = 1264, μ(MoKα) = 3.999 mm^(-1), Z = 4, Rint = 0.0308,(Δρ)_(max) = 0.354,(Δρ)_(min) = 0.289, R = 0.0332 and wR = 0.0721 for 2401 observed reflections(I 〉 2σ(I)). However, compound 2 crystallizes in triclinic, space group P1 with a = 10.315(2), b = 14.060(3), c = 15.090(3) A, β = 98.40(3)o, V = 1990.0(9) ?~3, D_c = 1.527 g/cm^3, C_(48)H_(34)N_8O_5Cd, M_r = 915.23, F(000) = 932, μ(MoKα)= 0.610 mm^(-1), Z = 2, Rint = 0.0776,(Δρ)_(max) = 0.869,(Δρ)_(min) = 0.843, R = 0.0815 and wR = 0.1930 for 6999 observed reflections(I 〉 2σ(I)). Compound 1 is a 1D chain structure, which adopts inorganic anion I- as the counterion, and 2 exists a 2D(4,4) network constructed by benzene-1,4-dicarboxylic acid. 展开更多
关键词 ancillary ligand crystal structure fluorescence
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Types of the National Markets of Ancillary Services and Balancing Energy
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作者 Ana Horvat Sedlie Niko Mandie Bosko Milesevie 《Journal of Energy and Power Engineering》 2013年第10期1884-1891,共8页
Modeling of ancillary services market can be described as institutional arrangements for establishing ancillary services management in deregulated electricity market. Models of the national ancillary services markets ... Modeling of ancillary services market can be described as institutional arrangements for establishing ancillary services management in deregulated electricity market. Models of the national ancillary services markets are market models which offer transmission system operator efficient procurement of ancillary services, reducing the system management risk, more competitive electricity market, better utilization of production facilities and complete deregulation of electricity markets. This paper deals with current mode of ancillary services market and potential market development in Croatia. Described models are used for establishing market of ancillary services which should occur in parallel with the electricity market. 展开更多
关键词 ENERGY ancillary services balancing market models.
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Advances in computed tomography and magnetic resonance imaging of hepatocellular carcinoma 被引量:16
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作者 Tiffany Hennedige Sudhakar K Venkatesh 《World Journal of Gastroenterology》 SCIE CAS 2016年第1期205-220,共16页
Hepatocellular carcinoma(HCC)is the most common primary liver cancer.Imaging is important for establishing a diagnosis of HCC and early diagnosis is imperative as several potentially curative treatments are available ... Hepatocellular carcinoma(HCC)is the most common primary liver cancer.Imaging is important for establishing a diagnosis of HCC and early diagnosis is imperative as several potentially curative treatments are available when HCC is small.Hepatocarcinogenesis occurs in a stepwise manner on a background of chronic liver disease or cirrhosis wherein multiple genes are altered resulting in a range of cirrhosisassociated nodules.This progression is related to increased cellularity,neovascularity and size of the nodule.An understanding of the stepwise progression may aid in early diagnosis.Dynamic and multiphase contrast-enhanced computed tomography and magnetic resonance imaging still form the cornerstone in the diagnosis of HCC.An overview of the current diagnostic standards of HCC in accordance to the more common practicing guidelines and their differences will be reviewed.Ancillary features contribute to diagnostic confidence and has been incorporated into the more recent Liver Imaging Reporting and Data System.The use of hepatocyte-specific contrast agents is increasing and gradually changing the standard of diagnosis of HCC;the most significant benefit being the lack of uptake in the hepatocyte phase in the earlier stages of HCC progression.An outline of supplementary techniques in the imaging of HCC will also be reviewed. 展开更多
关键词 HEPATOCELLULAR CARCINOMA COMPUTEDTOMOGRAPHY Magnetic resonance imaging Contrastagent CIRRHOSIS ancillary features
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Land Cover Classification with Multi-source Data Using Evidential Reasoning Approach 被引量:3
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作者 LI Huapeng ZHANG Shuqing +1 位作者 SUN Yan GAO Jing 《Chinese Geographical Science》 SCIE CSCD 2011年第3期312-321,共10页
Land cover classification is the core of converting satellite imagery to available geographic data.However,spectral signatures do not always provide enough information in classification decisions.Thus,the application ... Land cover classification is the core of converting satellite imagery to available geographic data.However,spectral signatures do not always provide enough information in classification decisions.Thus,the application of multi-source data becomes necessary.This paper presents an evidential reasoning (ER) approach to incorporate Landsat TM imagery,altitude and slope data.Results show that multi-source data contribute to the classification accuracy achieved by the ER method,whereas play a negative role to that derived by maximum likelihood classifier (MLC).In comparison to the results derived based on TM imagery alone,the overall accuracy rate of the ER method increases by 7.66% and that of the MLC method decreases by 8.35% when all data sources (TM plus altitude and slope) are accessible.The ER method is regarded as a better approach for multi-source image classification.In addition,the method produces not only an accurate classification result,but also the uncertainty which presents the inherent difficulty in classification decisions.The uncertainty associated to the ER classification image is evaluated and proved to be useful for improved classification accuracy. 展开更多
关键词 evidential reasoning Dempster-Shafer theory of evidence multi-source data geographic ancillary data land cover classification classification uncertainty
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MILP Optimization Model for Assessing the Participation of Distributed Residential PV-battery Systems in Ancillary Services Market 被引量:2
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作者 Pierluigi Siano Dolatabadi Mohammad 《CSEE Journal of Power and Energy Systems》 SCIE CSCD 2021年第2期348-357,共10页
A novel non-linear stochastic method based on a Mixed-Integer Linear Programming(MILP)optimization model is proposed to optimally manage a high number of photovoltaic(PV)-battery systems for the provision of up and do... A novel non-linear stochastic method based on a Mixed-Integer Linear Programming(MILP)optimization model is proposed to optimally manage a high number of photovoltaic(PV)-battery systems for the provision of up and down regulation in the ancillary services market.This method,considers both the technical constraints of the power system,and those of the equipment used by all the prosumers.This allows an aggregator of many residential prosumers endowed with photovoltaic(PV)-battery systems to evaluate the baseline of the aggregate by minimizing the costs related to the electrical energy absorbed from the grid and then to assess the up and down flexibility curves with relative offer prices.As confirmed by simulation results carried out considering different realistic case studies,the method can effectively be used by an aggregator to evaluate the economic impact of its participation in the ancillary services market,both for the aggregator and for its prosumers. 展开更多
关键词 Aggregator ancillary services market mixed-integer linear programming optimization PV-battery systems up and down regulation
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Optoelectronic properties of new functionalized heteroleptic iridium complex
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作者 梁波 王磊 +1 位作者 张勇 曹镛 《Journal of Central South University》 SCIE EI CAS 2011年第1期63-67,共5页
A new functionalized heteroleptic iridium complex coordinated with 1-phenylisoquinoline (1-piq) and a functionalized fl-diketone (G1), Ir(1-piq)2G1, was synthesized and characterized by 1H-NMR, mass spectrometry... A new functionalized heteroleptic iridium complex coordinated with 1-phenylisoquinoline (1-piq) and a functionalized fl-diketone (G1), Ir(1-piq)2G1, was synthesized and characterized by 1H-NMR, mass spectrometry and elemental analysis. The larger conjugation of the replacement of acetylacetone (acac) by a functionalizedβ-diketonate ligand led to a significant decrease in the HOMO level toward vacuum level, while Ir(1-piq)2G1 and Ir(1-piq)2(acac) showed red phosphorescent emissions of about 620 nm in dichloromethane solution. The phosphorescent polymer light-emitting devices were achieved, with the complexes incorporated with polyfluorene (PFO) as a host polymer doped with 30% of 5-(4-biphenylyl)-2-(4-tert-butylphenyl)-1,3,4-oxadiazole (PBD) as electron transport material. The energy transfer mechanism of the devices was also discussed. The lower EL performance of Ir(1-piq)2G1 is ascribed to the inter-ligand energy transfer, indicating that it is important to control the energy level of the cyclometalated and ancillary ligands. 展开更多
关键词 iridium complex PHOSPHORESCENCE energy transfer ancillary ligands
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A Geometric Morphometrics Study of Stigma-Anther Polymorphism in the Tropical Distylous <i>Palicourea padifolia</i>(Rubiaceae)
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作者 Angélica María Hernández-Ramírez José A. Aké-Castillo 《American Journal of Plant Sciences》 2014年第10期1449-1458,共10页
Distyly is a floral polymorphism with long-styled flowers and short-styled flowers. Traditionally, floral traits in distylous species have been studied as a variable composed of several linear measurements. We propose... Distyly is a floral polymorphism with long-styled flowers and short-styled flowers. Traditionally, floral traits in distylous species have been studied as a variable composed of several linear measurements. We proposed the use of a geometric morphometric approach to studying flower shape and entire flower design variation (including stigma-anther polymorphism) between morphs in Palicourea padifolia. The geometric morphometric approach allowed us to preserve the integrity of the floral form and to project the floral features on the same scale. Moreover, the visualization of a grid deformation allows us to describe shape differences between morphs as well as to estimate the variance-covariance matrix among floral traits. In this study, we demonstrated that flower shape and entire flower design differed between morphs. Intra- and inter-morph variations in the flower size were observed. The flower size has an effect on the anther position between morphs and among individuals. An association between flower shape and flower size was observed in both morphs. A pattern of floral features co-variation between the morphs was demonstrated in the species. In P. padifolia both morphs seemed to be internally coherent with respect to the developmental processes that produce flower shape variation. Changes in floral traits associated with flower size seemed to be more complex than those in the simple uniform expansion of the floral trait positions analogous between morphs. The observed pattern of co-variation of floral features between morphs suggested that flower base shape would be an additionally ancillary trait linked to the stigma-anther polymorphism in the species. 展开更多
关键词 ancillary Traits FLOWER Shape and Entire FLOWER Design HETEROSTYLY Landmark PROCRUSTES
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Confounding of Three Binary-Variable Counterfactual Model with DAG
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作者 Jingwei Liu Shuang Hu 《Applied Mathematics》 2013年第10期1397-1404,共8页
Confounding of three binary-variable counterfactual model with directed acyclic graph (DAG) is discussed in this paper. According to the effect between the control variable and the covariate variable, we investigate t... Confounding of three binary-variable counterfactual model with directed acyclic graph (DAG) is discussed in this paper. According to the effect between the control variable and the covariate variable, we investigate three causal counterfactual models: the control variable is independent of the covariate variable, the control variable has the effect on the covariate variable and the covariate variable affects the control variable. Using the ancillary information based on conditional independence hypotheses and ignorability, the sufficient conditions to determine whether the covariate variable is an irrelevant factor or whether there is no confounding in each counterfactual model are obtained. 展开更多
关键词 CAUSAL Effect INDEPENDENCE Hypothesis COUNTERFACTUAL Model CONFOUNDING Bias Irrelevant ancillary Information Directed ACYCLIC Graph
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New Analytical Model for Optimal Placement of Wind Turbines in Power Network under Pool and Reserve Markets Conditions
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作者 Babak Safari Chabok Ahmad Ashouri +2 位作者 Majid Yekta Khalilsaraei Hossein Shahidi Moghadam Fariborz Ghasemi 《Energy and Power Engineering》 2016年第10期313-325,共13页
In this paper a new market based analytical model is proposed for optimal placement of Wind Turbines (WTs) in power systems. In addition to wind turbines, thermal units (THUs) and Pumped Storage Hydro Power Plants (PS... In this paper a new market based analytical model is proposed for optimal placement of Wind Turbines (WTs) in power systems. In addition to wind turbines, thermal units (THUs) and Pumped Storage Hydro Power Plants (PSHPPs) owners participate in power market. Objective function is defined as participants’ social welfare achieved from power pool and ancillary markets in yearly horizon. Wind turbines have been modeled by probability-generation tree scenarios based on statistical information. We concentrate on investment profits of WTs numbers and its generation capacity beside to PSHPPs and THUs power plants in power systems due to increase in high flexible tools for Independent system operator into the planning and operation planning time interval. For effectiveness evaluation of proposed model, simulation studies are applied on 14-Bus IEEE test power system. 展开更多
关键词 Wind Turbine Pumped Storage Hydro Power Plants (PSHPPs) Power Pool and ancillary Market Independent system Operator
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Mechanism Design for Ancillary Service Market Considering Social Welfare and Fairness
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作者 Zhi Wu Yuanxi Wu +3 位作者 Wei Gu Zheng Xu Shu Zheng Jingtao Zhao 《CSEE Journal of Power and Energy Systems》 SCIE EI CSCD 2024年第3期1000-1010,共11页
Increasing penetration of distributed energy resources in the distribution network(DN)is threatening safe operation of the DN,which necessitates setup of the ancillary service market in the DN.In the ancillary service... Increasing penetration of distributed energy resources in the distribution network(DN)is threatening safe operation of the DN,which necessitates setup of the ancillary service market in the DN.In the ancillary service market,distribution system operator(DSO)is responsible for safety of the DN by procuring available capacities of aggregators.Unlike existing studies,this paper proposes a novel market mechanism composed of two parts:choice rule and payment rule.The proposed choice rule simultaneously considers social welfare and fairness,encouraging risk-averse aggregators to participate in the ancillary service market.It is then formulated as a linear programming problem,and a distributed solution using the multi-cut Benders decomposition is presented.Moreover,successful implementation of the choice rule depends on each aggregator’s truthful adoption of private parameters.Therefore,a payment rule is also designed,which is proved to possess two properties:incentive compatibility and individual rationality.Simulation results demonstrate effectiveness of the proposed choice rule on improving fairness and verify properties of the payment rule. 展开更多
关键词 Aggregator ancillary service market distributed mechanism FAIRNESS mechanism design
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Design of Robust Var Reserve Contract for Enhancing Reactive Power Ancillary Service Market Efficiency
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作者 Yunyang Zou Yan Xu 《CSEE Journal of Power and Energy Systems》 SCIE EI CSCD 2024年第2期767-771,共5页
In a deregulated Var market, market power issue is more serious than in an energy market since reactive power cannot be transmitted over long distances. This letter designs a multi-timescale Var market framework, wher... In a deregulated Var market, market power issue is more serious than in an energy market since reactive power cannot be transmitted over long distances. This letter designs a multi-timescale Var market framework, where market power that may arise in the hourly-ahead Var support service market due to system configuration deficiency and market structure flaws can be eliminated by day-ahead contract-based Var reserve service market. Settlement of day-ahead Var reserve contract is formulated as a two-stage robust optimization (TSRO) model considering worst case of uncertainty realization and potential market power that may arise in hourly-ahead market. TSRO with integer recourses is then solved by a new column and constraint generation algorithm. Results show a robust Var reserve contract can fully eliminate market power, and prevent suppliers from manipulating market prices. 展开更多
关键词 Market efficiency market power reactive power ancillary service two-stage robust optimization Var reserve
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Power system flexibility: an overview of emergence to evolution 被引量:20
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作者 Alireza AKRAMI Meysam DOOSTIZADEH Farrokh AMINIFAR 《Journal of Modern Power Systems and Clean Energy》 SCIE EI CSCD 2019年第5期987-1007,共21页
Power systems are evolving to the networks with proliferated penetration of renewable energy resources to leverage their environmental and economic advantages However,due to the stochastic nature of renewables,the man... Power systems are evolving to the networks with proliferated penetration of renewable energy resources to leverage their environmental and economic advantages However,due to the stochastic nature of renewables,the management of the rapidly increasing uncertainty and variability in power system planning and operation is of crucial significance.This paper represents a comprehensive overview of power system flexibility as an effective way to maintain the power balance at every moment.Definitions of power system flexibility from various aspects are explained to reach the reliable and economic planning and operation of the power system.The effects of the high penetration of variable energy resources on power systems and the evolution of flexibility in response to renewables are studied.A variety of resources during the flexibility evolutionary transition are introduced and discussed.As an influential flexibility solution in current power systems integrated with renewable resources,market design improvement is widely reviewed in this paper,and required modifications in market design mechanisms are investigated pertaining to various time horizons. 展开更多
关键词 Power system FLEXIBILITY RENEWABLE energy RESOURCES ancillary services ELECTRICITY market design
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Energy Management and Operational Control Methods for Grid Battery Energy Storage Systems 被引量:28
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作者 Xiangjun Li Shangxing Wang 《CSEE Journal of Power and Energy Systems》 SCIE CSCD 2021年第5期1026-1040,共15页
Energy storage is one of the key means for improving the flexibility,economy and security of power system.It is also important in promoting new energy consumption and the energy Internet.Therefore,energy storage is ex... Energy storage is one of the key means for improving the flexibility,economy and security of power system.It is also important in promoting new energy consumption and the energy Internet.Therefore,energy storage is expected to support distributed power and the micro-grid,promote open sharing and flexible trading of energy production and consumption,and realize multi-functional coordination.In recent years,with the rapid development of the battery energy storage industry,its technology has shown the characteristics and trends for large-scale integration and distributed applications with multi-objective collaboration.As a grid-level application,energy management systems(EMS)of a battery energy storage system(BESS)were deployed in real time at utility control centers as an important component of power grid management.Based on the analysis of the development status of a BESS,this paper introduced application scenarios,such as reduction of power output fluctuations,agreement to the output plan at the renewable energy generation side,power grid frequency adjustment,power flow optimization at the power transmission side,and a distributed and niohile energy storage system at the power distribution side.The studies and application status of a BESS in recent years were reviewed.The energy management,operation control methods,and application scenes of large-scale BESSs were also examined in the study. 展开更多
关键词 Battery energy storage system(BESS) energy management systems(EMS) multi-objective collaborative control new energy integration power grid ancillary service.
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