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Rationality of quotients by linear actions of affine groups

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Science China Mathematics 2011年第8期54卷 1521-1532页

作者： BOGOMOLOV Fedor BHNING Christian graf von BOTHMER Hans-Christian Department of Mathematics Courant Institute of Mathematical Sciences New York University Mathematisches Institut University of Gottingen

LetG = SLn(C)Cn be the (special) affine group. In this paper we study the representation theory of G and in particular the question of rationality for V/G, where V is a generically free G-representation. We show that the answer to this question is positive (Theorem 6.1) if the dimension of V is sufficiently large and V is indecomposable. We explicitly characterize two-step extensions 0 → S → V → Q → 0, with completely reducible S and Q, whose rationality cannot be obtained by the methods presented here (Theorem 5.3).

关键词： rationality linear group quotients affine groups

Achieving high union rates after first metatarsophalangeal joint arthrodesis:Radiographic outcomes and technical pitfalls

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World Journal of Orthopedics 2023年第6期14卷 436-442页

作者： Christian von Deimling Timo Tondelli Samuel Brunner Octavian Andronic Alexander David graf Department of Orthopedic Surgery and Traumatology Bürgerspital SolothurnSolothurn 4500Switzerland

BACKGROUND Fusion of the first metatarsophalangeal(MTP1)joint is a common surgery performed to correct hallux rigidus,hallux rigidus et valgus and other painful degenerative diseases of the *** To assess outcomes of our surgical technique including non-union rates,accuracy and aims of *** Between September 2011 and November 2020 a total 72 of MTP1 fusions were performed using a low profile,pre-contoured dorsal locking plate and a plantar compression *** and revision rates were analyzed with a minimum clinical and radiological follow up of at least 3 mo(range 3-18 mo).The following parameters were evaluated on pre-and postoperative conventional radiographs:Intermetatarsal angle,Hallux-valgus angle,dorsal extension of the proximal phalanx(P1)in relation to the floor and the angle between the Metatarsal 1 and the P1(MT1-P1 angle).Descriptive statistical analysis was *** analysis was used to assess for correlations between radiographic parameters and achievement of *** An overall union rate of 98.6%(71/72)was *** out of 72 patients did not primarily fuse with one patient suffering from a non-union,whilst the other demonstrating a radiological delayed union without clinical symptoms,with eventually complete fusion after 18 *** was no correlation between the measured radiographic parameters and the achievement of *** believe the reason for the non-union was mainly attributed to the patient’s incompliance without wearing the therapeutic shoe leading to a fracture of the ***,we didn`t find any correlation between fusion and the degree of *** With our surgical technique,high union rates(98%)can be achieved using a compression screw and a dorsal variable-angle locking plate to treat degenerative diseases of the MTP1.

关键词： Arthrodesis First metatarsophalangeal joint Dorsal plate Arthrodesis

Freeform path fitting for the minimisation of the number of transitions between headland path and interior lanes within agricultural fields

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Artificial Intelligence in Agriculture 2021年第1期5卷 233-239页

作者： Mogens graf Plessen MGP is an independent researcher

Within the context of in-field path planning this paper discusses freeformpath fitting for theminimisation of the number of transitions between headland path and interior laneswithin agricultural *** topic ismotivated by two *** to crossings of tyre traces such transitions in practice often cause an increase of compacted ***,for very tight angles between headland path and interior lanes undesired hairpin turnsmay becomenecessary due to the limited agility of in-field operating *** the number of interior lanes both detrimental effects can be *** potential of minimising the number of interior lanes by freeform path fitting is evaluated on 10 non-convex real-world fields including obstacle areas,and compared to the more common technique of fitting straight interior lanes.

关键词： In-field path planning Freeform path fitting Agricultural logistics

Hydroprocessing and Blending of a Biomass-Based DTG-Gasoline

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Energy Engineering 2022年第6期119卷 2169-2192页

作者： David graf Philipp Neuner Reinhard Rauch Department Fuel Technology(EBI-ceb) Karlsruhe Institute of Technology(KIT)Engler-Bunte-InstituteKarlsruhe76131Germany

The number of annually registered internal-combustion vehicles still exceeds electric-driven ones in most regions,e.g.,*** goals are disclosed with the European Green Deal,which calls for new technical approaches and greenhouse gas neutral transition *** bridging technologies are synthetic fuels for®the transportation sector,e.g.,using the bioliq process for a CO_(2)-neutral gasoline *** must meet the applicable national standards to be used in existing *** parameters can be variably adapted to their requirements by *** this work,we considered the upgrading of aromatic-rich DTG®gasoline from the bioliq *** heavy gasoline was therefore separated from the light one by *** investigated how to selectively modify the petrochemical parameters of the heavy gasoline,especially the boiling characteristics,to make the product suitable as a high-quality blending *** commercially available Pt/zeolite catalysts were tested over a wide range of temperature and space *** achieved high gasoline yields,while the content of light end compounds up to a boiling temperature of 150°C could be increased *** contrast to the high naphthenic content of the gasoline,the obtained octane numbers were *** the Motor Octane Number turned out unexpectedly high and showed a dependency on the isomerization of the naphthenic *** blending the upgraded heavy gasoline with the previously separated light gasoline,we could finally show that hydroprocessing is suitable for adjusting petrochemical *** aromatic concentration was 37.5%lower than that in the original raw gasoline,while the boiling characteristics improved ***,the final boiling point was 82°C lower,which is beneficial for the emission behavior.

关键词： Synthetic fuels upgrading durene dimethyl ether to gasoline refinery

The Role of Stationary and Transient Planetary Waves in the Maintenance of Stratospheric Polar Vortex Regimes in Northern Hemisphere Winter

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Advances in Atmospheric Sciences 2011年第1期28卷 187-194页

作者：李倩 Hans-F.graf 崔雪锋 Key Laboratory of Middle Atmosphere and Global Environment Observation Institute of Atmospheric PhysicsChinese Academy of Sciences School of GeoSciences University of Edinburgh Center for Atmospheric Science University of Cambridge State Key Laboratory of Earth Surface Processes and Resource Ecology College of Global Change and Earth System ScienceBeijing Normal University

Using 1958-2002 NCEPNCAR reanalysis data, we investigate stationary and transient planetary wave propagation and its role in wave-mean flow interaction which influences the state of the polar vortex （PV） in the stratosphere in Northern Hemisphere （NH） winter. This is done by analyzing the Eliassen-Palm （E-P） flux and its divergence. We find that the stationary and transient waves propagate upward and equatorward in NH winter, with stronger upward propagation of stationary waves from the troposphere to the stratosphere, and stronger equatorward propagation of transient waves from mid-latitudes to the subtropics in the troposphere. Stationary waves exhibit more upward propagation in the polar stratosphere during the weak polar vortex regime （WVR） than during the strong polar vortex regime （SVR）. On the other hand, transient waves have more upward propagation during SVR than during WVR in the subpolar stratosphere, with a domain of low frequency waves. With different paths of upward propagation, both stationary and transient waves contribute to the maintenance of the observed stratospheric PV regimes in NH winter.

关键词： stratospheric polar vortex planetary waves stationary transient

The Interannual Variability of East Asian Winter Monsoon and Its Relation to the Summer Monsoon

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Advances in Atmospheric Sciences 2000年第1期17卷 48-60页

作者：陈文 Han-F.graf 黄荣辉 Institute of Atmospheric Physics Chinese Academy of Sciences China Max-Planck-Institute of Meteorology Hamburg Germany

Based on the NCEP/ NCAR reanalysis data the interannual variability of the East Asian winter mon-soon (EAWM) is studied with a newly defined EAWM intensity index. The marked features for a strong (weak) winter monsoon include strong (weak) northerly winds along coastal East Asia, cold (warm) East Asian continent and surrounding sea and warm (cold) ocean from the subtropical central Pacific to the trop-ical western Pacific, high (low) pressure in East Asian continent and low (high) pressure in the adjacent ocean and deep (weak) East Asian trough at 500 hPa. These interannual variations are shown to be closely connected to the SST anomaly in the tropical Pacific, both in the western and eastern Pacific. The results suggest that the strength of the EAWM is mainly influenced by the processes associated with the SST anom-aly over the tropical Pacific. The EAWM generally becomes weak when there is a positive SST anomaly in the tropical eastern Pacific (El Ni?o), and it becomes strong when there is a negative SST anomaly (La Ni?a). Moreover, the SST anomaly in the South China Sea is found to be closely related to the EAWM and may persist to the following summer. Both the circulation at 850 hPa and the rainfall in China confirm the connection between the EAWM and the following East Asian summer monsoon. The possible reason for the recent 1998 summer flood in China is briefly discussed too. Key words East Asian winter monsoon - Interannual variability - SST - Summer monsoon This study was supported by “ National Key Programme for Developing Basic Sciences” G1998040900 part 1, and by key project (KZ 952-S1-404) of Chinese Academy of Sciences.

关键词： East Asian winter monsoon Interannual variability SST Summer monsoon

The Open Data Challenge:An Analysis of 124,000 Data Availability Statements and an Ironic Lesson about Data Management Plans

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Data Intelligence 2020年第4期2卷 554-568页

作者： Chris graf Dave Flanagan Lisa Wylie Deirdre Silver Wiley 9600 Garsington RoadOxford OX42DQUK

Data availability statements can provide useful information about how researchers actually share research *** used unsupervised machine learning to analyze 124,000 data availability statements submitted by research authors to 176 Wiley journals between 2013 and *** categorized the data availability statements,and looked at trends over *** found expected increases in the number of data availability statements submitted over time,and marked increases that correlate with policy changes made by *** open data challenge becomes to use what we have learned to present researchers with relevant and easy options that help them to share and make an impact with new research data.

关键词： Data availability statement(DAS) FAIR data Machine learning Trends Journal Policy

Paving the Way to Open Data

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Data Intelligence 2019年第4期1卷 368-380页

作者： Yan Wu Elizabeth Moylan Hope Inman Chris graf Wiley 805-808 Sun PalaceNo.12A Taiyanggong Middle RoadBeijing 100028China Wiley 9600 Garsington RoadOxfordOX42DQUK Wiley 111 River StreetHobokenNJ 07030USA

It is easy to argue that open data are critical to enabling faster and more effective research *** this article,we describe the approach we have taken at Wiley to support open data and to start enabling more data to be FAIR data(Findable,Accessible,Interoperable and Reusable)with the implementation of four data policies:“Encourages”,“Expects”,“Mandates”and“Mandates and Peer Reviews Data”.We describe the rationale for these policies and levels of adoption so *** the coming months we plan to measure and monitor the implementation of these policies via the publication of data availability statements and data *** this information,we’ll be able to celebrate adoption of data-sharing practices by the research communities we work with and serve,and we hope to showcase researchers from those communities leading in open research.

关键词： Open data Data sharing Data citation Open research

Data-driven smart charging for heterogeneous electric vehicle fleets

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Energy and AI 2020年第1期1卷 74-86页

作者： Oliver Frendo Jerome graf Nadine Gaertner Heiner Stuckenschmidt SAP SE Dietmar-Hopp-Allee 16Walldorf 69190Germany University of Mannheim Schloss68131 Mannheim

The ongoing electrification of mobility comes with the challenge of charging electric vehicles(EVs)sufficiently while charging infrastructure capacities are *** charging algorithms produce charge plans for indi-vidual EVs and aim to assign charging capacities fairly and efficiently between vehicles in a *** practice,EV charging processes follow nonlinear charge profiles such as constant-current,constant-voltage(CCCV).Smart charging must consider charge profiles in order to avoid gaps between charge plans and actual EV power *** valid models of charge profiles and their parameters for a diverse set of EVs are not publicly *** this work we propose a data-driven approach for integrating a machine learning model to pre-dict arbitrary charge profiles into a smart charging *** train machine learning models with a dataset consisting of charging processes from the workplace gathered in 2016–2018 from a heterogeneous EV fleet of 1001 EVs with 18 unique *** charging process includes the time series of charging *** pre-processing,the dataset contains 10.595 charging processes leading to 1.2 million data points in *** then compare different machine learning models for charge profile predictions finding that XGBoost yields the most accurate predictions with a mean absolute error(MAE)of 126W and a relative MAE of *** show that smart charging with the integrated XGBoost model leads to a more effective infrastructure usage with up to 21%more energy charged compared to smart charging without considering charge ***,an ablation study on regression model features shows the EV’s model is not a necessary attribute for accurate charge profile ***,charging features are required including the number of phases used for charging.

关键词： Smart charging Electric vehicles Data-driven approach Machine learning