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Identification of abnormal tribological regimes using a microphone and semi-supervised machine-learning algorithm

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Friction 2022年第4期10卷 583-596页

作者： Vigneashwara PANDIYAN Josef PROST georg VORLAUFER Markus VARGA Kilian WASMER Laboratory for Advanced Materials Processing(LAMP) Swiss Federal Laboratories for Materials Science and Technology(Empa)Thun CH-3602Switzerland AC2T research GmbH Viktor-Kaplan-Straße 2/CWiener Neustadt 2700Austria

Functional surfaces in relative contact and motion are prone to wear and tear,resulting in loss of efficiency and performance of the workpieces/*** occurs in the form of adhesion,abrasion,scuffing,galling,and scoring between ***,the rate of the wear phenomenon depends primarily on the physical properties and the surrounding *** the integrity of surfaces by offline inspections leads to significant wasted machine time.A potential alternate option to offline inspection currently practiced in industries is the analysis of sensors signatures capable of capturing the wear state and correlating it with the wear phenomenon,followed by in situ classification using a state-of-the-art machine learning(ML)*** this technique is better than offline inspection,it possesses inherent disadvantages for training the ML ***,supervised training of ML models requires the datasets considered for the classification to be of equal weightage to avoid *** collection of such a dataset is very cumbersome and expensive in practice,as in real industrial applications,the malfunction period is minimal compared to normal ***,classification models would not classify new wear phenomena from the normal regime if they are *** a promising alternative,in this work,we propose a methodology able to differentiate the abnormal regimes,i.e.,wear phenomenon regimes,from the normal *** is carried out by familiarizing the ML algorithms only with the distribution of the acoustic emission(AE)signals captured using a microphone related to the normal *** a result,the ML algorithms would be able to detect whether some overlaps exist with the learnt distributions when a new,unseen signal *** achieve this goal,a generative convolutional neural network(CNN)architecture based on variational auto encoder(VAE)is built and *** the validation procedure of the proposed CNN architectures,we were

关键词： surface integrity acoustic emission auto encoders condition monitoring wear prediction

Comprehensive review of tribometer dynamics-Cycle-based data analysis and visualization

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Friction 2022年第5期10卷 772-786页

作者： Josef PROST Guido BOIDI Thomas LEBERSORGER Markus VARGA georg VORLAUFER AC2Tresearch GmbH Wiener Neustadt 2700Austria

Tribologists often rely on triboexperiments to investigate factors that affect a *** inherent dynamic behavior of the respective tribometer setups and its effect on data interpretation remain often *** this study,a comprehensive analysis of sensor data obtained from lubricated and dry triboexperiments is *** are generated on a pin-on-disc test rig with a silicon nitride ball on a steel disc contact with a rotation frequency of~3 ***-speed acquisition of sensor data up to 5 kHz is performed to resolve changes in the data within individual *** characteristic frequencies of the system and their temporal evolution are determined via time--frequency analysis,which reveals periodic patterns in the sensor ***-based data evaluation allows the detection of localized events and changes during an operation and considerably reduces the apparent measurement uncertainty,as compared with an unreduced *** data analysis and visualization routines presented herein may serve as a prototype for further application to tribometer setups.

关键词： high-speed data acquisition time-frequency analysis(TFA) cycle-resolved analysis pin-on-disc tribometer

Control Evaluation of Antagonistic Series Elastic Actuation for a Robotic Endoscope Joint

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Journal of Bionic Engineering 2022年第4期19卷 965-974页

作者： Lorin Fasel Nicolas Gerig Philippe C.Cattin georg Rauter BIROMED-Lab Department of Biomedical EngineeringUniversity of Basel4123AllschwilSwitzerland CIAN Department of Biomedical EngineeringUniversity of Basel4123AllschwilSwitzerland

Haptic feedback is typically missing during telemanipulation of surgical robots in minimally invasive surgeries,i.e.,surgeons cannot feel the interaction forces between the instruments and ***,surgeons have to solely rely on visual feedback,which increases complexity of guiding the instruments and poses the safety threat of unperceivable contacts outside the field of *** propose a novel series elastic actuation design for articulated robotic endoscopes to overcome these limitations and evaluate an according device with one *** to the actuation of human fingers,the joint is driven by antagonistic *** are integrated in the transmission between the tendons and the motors outside of the endoscope *** estimated the joint angle and thereby the endoscope shape,measured spring deflection,estimated tendon forces from that deflection,and implemented force control for the endoscope *** torque control and impedance control were evaluated under application of both a continuous force and an impact force to the endoscope *** springs reduced impact forces at the tip of the endoscope through their inherent *** the same time,feeding back the estimated force resulted in a stable tendon force control and a tunable endoscope joint control:Zero torque control effectively reduced the external forces,while the endoscope joint showed the expected stiffness in impedance *** results show that antagonistic series elastic actuation is a promising concept for endoscope joint actuation and that it can lead towards safer robot–tissue interactions in surgical robotics.

关键词： Minimally invasive surgery RAMIS Robot-assisted surgery Haptic feedback Force control Tendon-driven robotics

Using high-resolution aerial images to study gully development at the regional scale in southern China

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International Soil and Water Conservation Research 2020年第2期8卷 173-184页

作者： Honghu Liu georg Hormann Bingyu Qi Qiuxing Yue State Key Lab Soil Erosion and Dryland Farming on the Loess Plateau Institute of Soil and Water ConservationChinese Academy of Sciences and Ministry of Water ResourcesXinong Rd 26712100YanglingShaanxi ProvincePR China Changjiang River Scientific Research Institute Changjiang Water Resource CommissionNo 23 Huangpuda Street430010WuhanHubei provincePR China Department of Hydrology and Water Resources Management Institute of Natural Resource ConservationKiel UniversityOlshausenstr.75D-24098 KielGermany

There are 239,100 gullies in southern China,which cause the degradation of ecological ***,studies on gully development at the regional scale is relatively *** purpose of this study is to analyze the regional gully dynamics and explore how land use and topographic factors affect gully *** data consists of land use maps derived from high-resolution images from 2004 to 2014,and topography maps from a digital elevation model with a pixel size of 8 m×8 m in two 25-km2 study sites of Anxi(AX)and Xingning county(XN).The following results were obtained:(1)AX gullies decreased from 2006 to 2014 while XN first increased from 2004 to 2009,and then decreased from 2009 to *** AX and XN gully area in percentage of the total area ranged from 1%to 3%,which was higher than the average 0.25%of the whole southern China by the artificial survey in 2005.(2)Most of AX and XN gullies occurred along the ridgeline and had the close relationships with the upstream contributing area and slope gradient.(3)New gullies developed on the exposed land and *** lost gullies were converted into forestland and *** fact,most of these gullies were only covered by vegetation,not real *** results proved that gully decreased,but construction of roads and buildings intensified gully ***,these findings reveal that vegetation protection and ecological restoration should be adopted in southern China.

关键词： Digital elevation model Slope gradient Exposed lands Upstream contributing area

GEI—An idea whose time has come

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Global Energy Interconnection 2018年第1期1卷 1-3页

作者： georg Kell United Nations Global Compact GEIDCO

Global Energy Interconnection(GEI)is a bold venture for the generation,transmission,and use of clean energy,applying a smart grid as well as ultra-high voltage transmissions to transport renewable energy over long distances and with minimal *** its organizational arm,the Global Energy Interconnection Development Cooperation Organization(GEIDCO),GEI pursues

关键词： GEI An idea whose time has come

ADAPTIVITY IN SPACE AND TIME FOR MAGNETOQUASISTATICS

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Journal of Computational Mathematics 2009年第5期27卷 642-656页

作者： Markus Clemens Jens Lang Delia Teleaga georg Wimmer Helmut-Schmidt-Universitat Hamburg Holstenhofweg 8522043 HamburgGermany Technische Universitat Darmstadt Schlossgartenstraβe 764289 DarmstadtGermany

This paper addresses fully space-time adaptive magnetic field computations. We describe an adaptive Whitney finite element method for solving the magnetoquasistatic formulation of Maxwell＇s equations on unstructured 3D tetrahedral grids. Spatial mesh re- finement and coarsening are based on hierarchical error estimators especially designed for combining tetrahedral H（curl）-conforming edge elements in space with linearly implicit Rosenbrock methods in time. An embedding technique is applied to get efficiency in time through variable time steps. Finally, we present numerical results for the magnetic recording write head benchmark problem proposed by the Storage Research Consortium in Japan.

关键词： Magnetoquasistatics Space-time adaptivity Edge elements Rosenbrock meth-ods Hierarchical error estimator SRC benchmark problem.

Seed production,seed dispersal and seedling establishment of two afromontane tree species in and around a church forest：implications for forest restoration

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Forest Ecosystems 2016年第4期3卷 287-296页

作者： Abrham Abiyu Demel Teketay Gerhard Glatzel georg Gratzer Amhara Agricultural Research Institute P. O. Box 527 Bahir Dar Ethiopia Department of Crop Science and Production Botswana University of Agriculture and Natural Resources Private Bag 0027 Gaborone Botswana Institute of Forest Ecology University of Natural Resources and Life Sciences Peter Jordan Strage 82 A-1190 Vienna Austria

Background：Seed production,seed dispersal and seedling establishment are relevant life phases of *** these processes and their patterns is essential to recognize vegetation dynamics and to apply it to forest ***：For Olea europaea and Schefflera abyssinica,fecundity was estimated using randomized branch *** dispersal and seedling establishment were monitored using spatially explicit seed traps and *** functions were calibrated applying inverse ***：*** produced more seeds and had longer dispersal distances compared to *** between observed and predicted number of recruits were statistically *** of the two species showed different niche ***：The studied species were recruitment-limited due to low dispersal activity or lack of suitable *** relying on natural regeneration should overcome these limitations by increasing disperser visitation and reducing biotic and abiotic stresses.

关键词： Fecundity Olea europaea Schefflera abyssinica Recruitment limitation Restoration

Applications of membrane systems in distributed systems

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Progress in Natural Science:Materials International 2007年第4期17卷 401-410页

作者： Aneta Binder Rudolf Freund georg Lojka Marion Oswald Institute of Computer Languages Vienna University of TechnologyFavoritenstr. 9WienAustria

Based on the biological model of cell-to-cell communication proposed by A. Rustom et al. (Science, 2004, 303: 1007-1010), we investigate the possibilities to apply P systems with dynamic channels transporting membrane... 详细信息

关键词： membrane system P system communication process.

Necessity and Memory in Hegel's Phenomenology of Spurut A Reconstruction

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Frontiers of Philosophy in China 2018年第4期13卷 505-517页

作者： Hans-georg Moeller Philosophy and Religious Studies Program University of MacaoMacaoChina

This paper discusses two core concepts in Hegel’s Phenomenology of Spirit: necessity (Notwendigkeit) and memory (Erinnerung). The analysis is based on an investigation of the connotations and linguistic components of the two terms as they are used in the German language. Occurrences of the terms in decisive passages in the Phenomenology of Spirit are investigated and seen as a key to an understanding of Hegel’s overall project of constructing a “scientific” (wissenschaftlich) philosophy in the form of a conceptual system. The paper aims at showing that this project can in part be understood as an attempt to transform the contingency of all moments of the path of the self-cultivation, maturation, and growth (Bildung) of spirit (Geist)—understood both in terms of its personal dimension and as “world spirit”—into necessity. It is argued that memory plays a decisive role in this endeavor, not only in the sense of a recalling of the past, but also as a prerequisite for a future that opens up room for further cultivation, maturation, and growth.

关键词： Hegel Phenomenology of Spirit necessity memory system