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Hermitian geometry on the resolvent set(Ⅱ)

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Science China Mathematics 2021年第2期64卷 385-398页

作者： Ronald G.douglas Rongwei Yang Department of Mathematics Texas A&M UniversityCollege StationTX 77843USA School of Mathematical Sciences Tianjin Normal UniversityTianjin 300387China Department of Mathematics and Statistics State University of New York at AlbanyAlbanyNY 12222USA

For an element A in a unital C^(*)-algebra B,the operator-valued 1-formωA(z)=(z-A)^(-1) dz is analytic on the resolvent setρ(A),which plays an important role in the functional calculus of *** paper defines a class of Hermitian metrics onρ(A)through the coupling of the operator-valued(1,1)-formΩA=-ωA^(*)∧ωA with tracial and vector *** main goal is to study the connection between A and the properties of the metric concerning curvature,arc length,completeness and singularity.A particular example is when A is quasi-nilpotent,in which case the metric lives on the punctured complex plane C\{0}.The notion of the power set is defined to gauge the"blow-up"rate of the metric at 0,and examples are given to indicate a likely link with A’s hyper-invariant subspaces.

关键词： C^(*)-algebra Hermitian metric curvature arc length Fuglede-Kadison determinant quasi-nilpotent operator power set

High surface area biocarbon monoliths for methane storage

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Green Energy & Environment 2023年第5期8卷 1308-1324页

作者： Elizabeth Michaelis Renfeng Nie douglas Austin Yanfeng Yue Department of Chemistry Delaware State UniversityDoverDE 19901United States College of Chemical Engineering Zhengzhou UniversityZhengzhouHenan450001China

New energy sources that reduce the volume of harmful gases such as SO_(x)and NO_(x)released into the atmosphere are in constant *** gas,primarily made up of methane,is being widely used as one reliable energy source for heating and electricity generation due to its high combustion ***,natural gas accounts for a large portion of electricity generation and chemical feedstock in manufacturing plastics and other commercially important organic *** the near future,natural gas will be widely used as a fuel for ***,a practical storage device for its storage and transportation is very beneficial to the deployment of natural gas as an energy source for new *** this tutorial review,biomaterials-based carbon monoliths(CMs),one kind of carbonaceous material,was reviewed as an adsorbent for natural gas(methane)adsorption and storage.

关键词： Activated carbon Carbon monolith Methane storage High surface area Activation agent

Comparison of Principal Components Analysis,Independent Components Analysis and Common Components Analysis

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Journal of Analysis and Testing 2018年第3期2卷 235-248页

作者： douglas N.Rutledge INRA UMR GENIALAgroParisTechUniversitéParis-SaclayMassyFrance

The aim of this work is to describe and compare three exploratory chemometrical tools,principal components analysis,independent components analysis and common components analysis,the last one being a modification of the multi-block statistical method known as common components and specific weights *** three methods were applied to a set of data to show the differences and similarities of the results obtained,highlighting their complementarity.

关键词： Exploratory data analysis Chemometrics Principal components analysis Independent components analysis Common components analysis Common components and specific weights analysis

ANALYSIS OF THE IMPACT OF SAMPLE SIZE, ATTRIBUTE VARIANCE AND WITHIN-SAMPLE CHOICE DISTRIBUTION ON THE ESTIMATION ACCURACY OF MULTINOMIAL LOGIT MODELS USING SIMULATED DATA

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Journal of Systems Science and Systems Engineering 2018年第6期27卷 771-789页

作者： Minhui Zeng Ming Zhong John douglas Hunt Engineering Research Center for Transportation safety ofMOE Wuhan University of Technology Wuhan China School of Traffic and Transportation Engineering Changsha University of Science & Technology China National Engineering Research Center for Water Transportation Safety China Department of Civil and Environmental Engineering University of Waterloo Ontario Canada Department of Civil Engineering University of Calgary Alberta Canada

Literature review indicates that sample size, attribute variance and within-sample choice distribution of alternatives are important considerations in the estimation of multinomial logit （MNL） models, but their impacts on the estimation accuracy have not been systematically studied. Therefore, the objective of this paper is to provide an empirical examination to the above issues through a set of simulated discrete choice preference and rank ordered preference datasets. In this paper, the utility coefficients, alternative specific constants （ASCs）, and the mean and standard deviation of the four attributes for a set of seven hypothetical alternatives are specified as a priori. Then, synthetic datasets, with varying sample size, attribute variance and within-sample choice distribution are simulated. Based on these datasets, the utility coefficients and ASCs of the specified MNLs are re-estimated and compared with the original values specified as the priori. It is found that （1） the estimation accuracy of utility parameters increases as the sample size increases; （2） the utility coefficients can be re-estimated with reasonable accuracy, but the estimates of the ASCs are confronted with much larger errors; （3） as the variances of the alternative attributes increase, the estimation accuracy improves significantly; and （4） as the distribution of chosen choices becomes more balanced across alternatives within sample datasets, the hit-ratio decreases. The results indicate that （a） under a similar setting presented in this paper, a large sample consisting of a few thousand observations （3000 - 4000） may be needed in order to provide reasonable estimates for utility coefficients, particularly for ASCs; （b） a larger, but realistic attribute space is preferred in the stated preference survey design; and （c） choice datasets with unbalanced ＂chosen＂ choice frequency distribution is preferred, in order to better capture the elasticity between the ＂perceived utility＂ associated wit

关键词： Sample size attribute variance within-sample choice distribution simulated data

Patient interest in video recording of colonoscopy:A survey

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World Journal of Gastroenterology 2010年第4期16卷 458-461页

作者： Meghana Raghavendra douglas K Rex Division of Gastroenterology/Hepatology Indiana University Medical CenterIndianapolisIN 46202United States

AIM:To find if patients are interested in obtaining a video recording of their colonoscopy ***:We conducted a survey of outpatients presenting for colonoscopy regarding their interest in obtaining a video recording of their ***:Two hundred and forty-eight patients(mean age 57.9 years;57% male) were *** hundred and one patients(81%) were interested in obtaining a video *** significant predictors of patients' interest in the video recording were *** reading a brief educational paragraph explaining missed lesions during colonoscopy,135 patients(54%) were more interested in having a video recording,and none were less *** hundred and fifty-six patients(63%) were willing to pay for a video *** multivariable analyses,younger age was predictive of willingness to pay for a video *** history of colorectal cancer and a family history of colorectal cancer were predictive of willingness to pay a greater ***:Patients undergoing colonoscopy expressed substantial interest in obtaining a videorecording of their *** of missing lesions during colonoscopy increased interest in having a videorecording.

关键词： Colonoscopy Video recording Survey

Redefining the possibility of digital Earth and geosciences with spatial cloud computing

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International Journal of Digital Earth 2013年第4期6卷 297-312页

作者： Chaowei Yang Yan Xu douglas Nebert Center of Intelligent Spatial Computing for Water/Energy Sciences George Mason UniversityFairfaxVAUSA Microsoft Research RedmondWAUSA Federal Geographic Data Committee RestonVAUSA

Global challenges(such as economy and natural hazards)and technology advancements have triggered international leaders and organizations to rethink geosciences and Digital Earth in the new *** next generation visions pose grand challenges for infrastructure,especially computing *** gradual establishment of cloud computing as a primary infrastructure provides new capabilities to meet the *** paper reviews research conducted using cloud computing to address geoscience and Digital Earth needs within the context of an integrated Earth *** also introduce the five papers selected through a rigorous review process as exemplar research in using cloud capabilities to address the *** literature and research demonstrate that spatial cloud computing provides unprecedented new capabilities to enable Digital Earth and geosciences in the twenty-first century in several aspects:(1)virtually unlimited computing power for addressing big data storage,sharing,processing,and knowledge discovering challenges,(2)elastic,flexible,and easy-to-use computing infrastructure to facilitate the building of the next generation geospatial cyberin-frastructure,CyberGIS,CloudGIS,and Digital Earth,(3)seamless integration environment that enables mashing up observation,data,models,problems,and citizens,(4)research opportunities triggered by global challenges that may lead to breakthroughs in relevant fields including infrastructure building,GIScience,computer science,and geosciences,and(5)collaboration supported by cloud computing and across science domains,agencies,countries to collectively address global challenges from policy,management,system engineering,acquisition,and operation aspects.

关键词： EarthCube CloudGIS eScience Earthscience interoperability

Comment on “A numerical investigation of the acoustic mode waves in a deviated borehole penetrating a transversely isotropic formation”

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Science China(Physics,Mechanics & Astronomy) 2016年第8期59卷 89-90页

作者： Steve A.Horne douglas Miller CanYun Wang Chevron Energy Technology Corporation London El4 4HA UK Massachusetts Institute of Technology Boston 02139 USA CNPC Logging Company Ltd Beijing 102206 China

In the paper"A numerical investigation of the acoustic mode waves in a deviated borehole penetrating a transversely isotropic formation"by Liu et al.[1]numerical experiments are reported for a dipole sonic logging scenario with a deviated borehole penetrating a VTI anisotropic *** such a situation it is important to clearly define the meaning of group and phase velocities as this has led to much confusion in the literature as discussed by Miller,Horne and Walsh[2].

关键词： penetrating Comment on isotropic borehole logging sonic confusion dipole deviation clearly

Unconformity structures controlling stratigraphic reservoirs in the north-west margin of Junggar basin, North-west China

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Frontiers of Earth Science 2013年第1期7卷 55-64页

作者： Kongyou WU douglas PATON Ming ZHA School of Geoscience China University of Petroleum Qingdao 266555 China School of Earth and Environment University of Leeds Leeds LS2 9JT UK

Tectonic movements formed several unconfor- mities in the north-west margin of the Junggar basin. Based on data of outcrop, core, and samples, the unconformity is a structural body whose formation associates with weath- ering, leaching, and onlap. At the same time, the structural body may be divided into three layers, including upper layer, mid layer, and lower layer. The upper layer with good primary porosity serves as the hydrocarbon migration system, and also accumulates the hydrocarbon. The mid layer with compactness and ductility can play a role as cap rock, the strength of which increases with depth. The lower layer with good secondary porosity due to weathering and leaching can form the stratigraphic truncation traps. A typical stratigraphie reservoir lying in the unconformity between the Jurassic and Triassic in the north-west margin of the Junggar basin was meticulously analyzed in order to reveal the key controlling factors. The results showed that the hydrocarbon distribution in the stratigraphic onlap reservoirs was controlled by the onlap line, the hydro- carbon distribution in the stratigraphic truncation reser- voirs was confined by the truncation line, and the mid layer acted as the key sealing rock. So a conclusion was drawn that ＂two lines （onlap line and truncation line） and a body （unconformity structural body）＂ control the formation and distribution of stratigraphic reservoirs.

关键词： unconformity structural body stratigraphicreservoir key controlling factors Jurassic bottom north-west margin of the Junggar basin

Texture-based latent space disentanglement for enhancement of a training dataset for ANN-based classification of fruit and vegetables

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Information Processing in Agriculture 2023年第1期10卷 85-105页

作者： Khurram Hameed douglas Chai Alexander Rassau School of Engineering Edith Cowan University270 Joondalup DriveJoondalup WA 6027PerthAustralia

The capability of Convolutional Neural Networks(CNNs)for sparse representation has significant application to complex tasks like Representation Learning(RL).However,labelled datasets of sufficient size for learning this representation are not easily *** unsupervised learning capability of Variational Autoencoders(VAEs)and Generative Adversarial Networks(GANs)provide a promising solution to this issue through their capacity to learn representations for novel data samples and classification *** this research,a texture-based latent space disentanglement technique is proposed to enhance learning of representations for novel data samples.A comparison is performed among different VAEs and GANs with the proposed approach for synthesis of new data *** different VAE architectures are considered,a single layer dense VAE and a convolution based VAE,to compare the effectiveness of different architectures for learning of the *** GANs are selected based on the distance metric for disjoint distribution divergence estimation of complex representation learning *** proposed texture-based disentanglement has been shown to provide a significant improvement for disentangling the process of representation learning by conditioning the random noise and synthesising texture rich images of fruit and vegetables。

关键词： Information Maximisation(IM) Fruit and vegetables classification Representation Learning(RL) Variational Autoencoder(VAE) Generative Adversarial Network (GAN) Latent space disentanglement