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作者： Baque Dominique. (1945-)kiefer Anselm

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Wolfgang kiefer教授在第十九届全国光散射学术会议闭幕式上的致辞（英文）

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光散射学报 2018年第1期30卷 95-96页

作者： wolfgang kiefer 德国维尔茨堡大学

Ladies and gentlemen, dear Professor Chen：Bringing this 19th National Chinese Conference on Light Scattering to an end , it gives me great pleasure and honor to say a few words to you.

关键词：光散射学术会议

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Prediction of interfaces of geological formations using the multivariate adaptive regression spline method

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Underground Space 2021年第3期6卷 252-266页

作者： Xiaohui Qi Hao Wang Xiaohua Pan Jian Chu kiefer Chiam School of Civil and Environmental Engineering Nanyang Technological University639798Singapore Building and Construction Authority 200 Braddell Road579700Singapore

The design and construction of underground structures are significantly affected by the distribution of geological *** of the geological interfaces using limited data has been a difficult task.A multivariate adaptive regression spline(MARS)method capable of modeling nonlinearities automatically was used in this study to spatially predict the elevations of geological *** data from two sites in Singapore were used to evaluate the capability of the MARS method for predicting geological *** comparing the predicted values with the borehole data,it is shown that the MARS method has a mean of root mean square error of 4.4 m for the predicted elevations of the Kallang Formation–Old Alluvium *** addition,the MARS method is able to produce reasonable prediction intervals in the sense that the percentage of testing data covered by 95% prediction intervals was close to the associated confidence level,95%.More importantly,the prediction interval evaluated by the MARS method had a non-constant width that appropriately reflected the data density and geological complexity.

关键词： Geological interface Rockhead Multivariate adaptive regression spline Spatial prediction

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Prediction of rockhead using a hybrid N-XGBoost machine learning framework

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Journal of Rock Mechanics and Geotechnical Engineering 2021年第6期13卷 1231-1245页

作者： Xing Zhu Jian Chu Kangda Wang Shifan Wu Wei Yan kiefer Chiam School of Civil and Environment Engineering Nanyang Technological University618798Singapore State Key Laboratory of Geohazard Prevention and Geoenvironment Protection Chengdu University of TechnologyChengdu610059China Building and Construction Authority 200 Braddell Road579700Singapore

The spatial information of rockhead is crucial for the design and construction of tunneling or underground *** the conventional site investigation methods(*** drilling) could provide local engineering geological information,the accurate prediction of the rockhead position with limited borehole data is still challenging due to its spatial variation and great uncertainties *** the development of computer science,machine learning(ML) has been proved to be a promising way to avoid subjective judgments by human beings and to establish complex relationships with mega data ***,few studies have been reported on the adoption of ML models for the prediction of the rockhead *** this paper,we proposed a robust probabilistic ML model for predicting the rockhead distribution using the spatial geographic *** framework of the natural gradient boosting(NGBoost) algorithm combined with the extreme gradient boosting(XGBoost)is used as the basic *** XGBoost model was also compared with some other ML models such as the gradient boosting regression tree(GBRT),the light gradient boosting machine(LightGBM),the multivariate linear regression(MLR),the artificial neural network(ANN),and the support vector machine(SVM).The results demonstrate that the XGBoost algorithm,the core algorithm of the probabilistic NXGBoost model,outperformed the other conventional ML models with a coefficient of determination(R2)of 0.89 and a root mean squared error(RMSE) of 5.8 m for the prediction of rockhead position based on limited borehole *** probabilistic N-XGBoost model not only achieved a higher prediction accuracy,but also provided a predictive estimation of the ***,the proposed N-XGBoost probabilistic model has the potential to be used as a reliable and effective ML algorithm for the prediction of rockhead position in rock and geotechnical engineering.

关键词： Rockhead Machine learning(ML) Probabilistic model Gradient boosting

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Modelling Magnetization Transfer Considering Spin-Locking Effects

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Open Journal of Medical Imaging 2014年第4期4卷 199-204页

作者： Claus kiefer Support Center for Advanced Neuroimaging (SCAN) Institute for Diagnostic and Interventional Neuroradiology University Hospital Inselspital and University of Bern Bern Switzerland

Purpose: Recently it was demonstrated that spin-locking (SL) effects can manifest as pseudo magnetization transfer (MT). To our best knowledge the MT models proposed so far cannot distinguish between saturation effects caused by the MT preparation pulses and SL phenomena. Therefore a new MT model is proposed. Materials and Methods: A binary spin-bath model for magnetization transfer was extended in that sense that SL effects are considered. The new modified spin bath model was tested for a phantom with different agar concentrates (2%, 4%, 8%) and a MnCl2 (0.3 mM) solution. Results: The mean fitting error is 3.2 times lower for the modified model compared to the original model. Especially the parameter F for the fractional part of the bounded proton pool describes the situation for the MnCl2 (F = 0) better than the original model (F = 0.004). Conclusion: The proposed mathematical modifications of the binary spin-bath model considering SL seem to be a step in the right direction in that sense that the effects associated with SL are not interpreted as magnetization transfer.

关键词： MRI Magnetization Transfer Spin-Locking

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Simultaneous Echo Refocused Magnetization Transfer Imaging

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Open Journal of Medical Imaging 2014年第3期4卷 154-158页

Purpose: To increase the efficiency of densely encoded magnetization transfer imaging of the brain, we time-multiplex multiple slices within the same readout using simultaneous echo refocusing FLASH imaging with magnetization transfer (MT) preparation (MT-SER-FLASH). Materials and Methods: Inefficiency in total scan time results from the number of frequency samples needed for sufficient quality of quantitative parameter maps for a binary spin bath model. We present a highly efficient multiplexing method, simultaneous echo refocused magnetization transfer imaging (MT-SER-FLASH) for reducing the total scan time of MT imaging by one-third. The specific absorption rate (SAR) was also reduced by reducing the number of MT-pulses per volume. Results: 2D-MT-SER-FLASH is performed in 19 minutes rather than 1 hour, acceptable for routine clinical application. The SAR could be reduced to 69% instead of more than 100% with a standard 2D or 3D-FLASH with MT-preparation. Conclusion: The net reduction of scan time and SAR enables the use of quantitative model based magnetization transfer imaging within a clinical environment.

关键词： MRI Magnetization Transfer Imaging Fast Imaging Pulse Sequences Simultaneous Echo Refocusing

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Linear Raman and Femtosecond Four-wave Mixing Spectroscopies on Ⅱ-Ⅵ Semiconductor Quantum Dots

Linear Raman and Femtosecond Four-wave Mixing Spectroscopies...

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第十三届全国光散射学术会议

作者： W.kiefer Institut fuer Physikalische Chemie Universitaet Wuerzburg Am HublandD-97074 WuerzburgGermany

＜正＞The optical properties of low dimensional systems like quantum dots are of great interest in semiconductor *** dots are quasi zero-dimensional systems in which free carriers and lattice vibrations（phonons）show special quantization *** energy of the phonons and their dependence on the size of the microstructures in a nanometer range can be determined by linear Raman *** the low wavenumber Raman scattering from the spheroidal and quadrupolar

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Femto Raman at University and Colour Raman at Homelab

Femto Raman at University and Colour Raman at Homelab

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第十九届全国光散射学术会议

作者： W. kiefer Institute of Physical and Theoretical Chemistry University of Würzburg D-97074 Würzburg Germany Eisingen Laboratory for Applied Raman Spectroscopy（ELARS）

＜正＞In this lecture the author will first report on selected work using Femtosecond Coherent Anti-Stokes Raman Spectroscopy（Fs-CARS）,which had been performed around 2000 and 2003 in the Institute of Physical and

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Raman Spectroscopy of Laser-Trapped Microparticles——A Review

Raman Spectroscopy of Laser-Trapped Microparticles——A Revi...

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第二十届全国光散射学术会议（CNCLS20）

作者： W.kiefer Institute for Physical and Theoretical Chemistry University of Würzburg Eisingen Laboratory for Applied Raman Spectroscopy

＜正＞Arthur Ashkin received in 2018 the Nobel Prize in Physics [1] for the optical tweezers and their application to biological *** pioneering work started already in 1970 when he first demonstrated optical trapping and optical levitation of single microparticles [2].The application of these techniques to Raman spectroscopy had been first introduced by Thurn and kiefer in

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海洋初级生产力的一维物理生态耦合模型

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浙江大学学报（工学版） 2018年第5期52卷 1002-1013页

作者：胡晨孙志林 Dale A.kiefer 李明佳浙江大学海洋学院浙江杭州310058 University of Southern California Biological Sciences Department Los AngelesCA 90089USA

为了更有效研究海洋初级生产力量值,构建物理-生态耦合模型,探讨影响海洋初级生产力的动力及生态因素.通过增加对流和扩散模块、分离营养盐循环体系、改变浮游植物生长速率公式及加入叶绿素计算模块,分别优化Gill-Turner(简称GT)混合层... 详细信息

为了更有效研究海洋初级生产力量值,构建物理-生态耦合模型,探讨影响海洋初级生产力的动力及生态因素.通过增加对流和扩散模块、分离营养盐循环体系、改变浮游植物生长速率公式及加入叶绿素计算模块,分别优化Gill-Turner(简称GT)混合层模型与Schmittner(简称S)生态系统模型,进而建立新型物理-生态耦合模型.基于Mathematica二次开发平台对模型进行编程实现,用以模拟大西洋百慕大站和太平洋夏威夷站的海洋初级生产力,优化后耦合模型的模拟结果精度明显提高.模拟结果显示,两大海域初级生产力均具有冬季高夏季低的分布特征,混合层深度与浮游植物浓度是影响初级生产力分布的重要因素.

关键词：初级生产力物理-生态耦合模型大洋站

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