检索结果-南通市图书馆

Combinations of Feature Descriptors for Texture Image Classification

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Data Analysis and Information Processing 2014年第3期2卷 67-76页

作者： alexander Barley christopher Town University of Cambridge Computer Laboratory Cambridge UK

Texture recognition and classification is a widely applicable task in computer vision. A key stage in performing this task is feature extraction, which identifies sets of features that describe the visual texture of an image. Many descriptors can be used to perform texture classification;among the more common of these are the grey level co-occurrence matrix, Gabor wavelets, steerable pyramids and SIFT. We analyse and compare the effectiveness of these methods on the Brodatz, UIUCTex and KTH-TIPS texture image datasets. The efficacy of the descriptors is evaluated both in isolation and by combining several of them by means of machine learning approaches such as Bayesian networks, support vector machines, and nearest-neighbour approaches. We demonstrate that using a combination of features improves reliability over using a single feature type when multiple datasets are to be classified. We determine optimal combinations for each dataset and achieve high classification rates, demonstrating that relatively simple descriptors can be made to perform close to the very best published results. We also demonstrate the importance of selecting the optimal descriptor set and analysis techniques for a given dataset.

关键词： Image Processing Texture Analysis Computer Vision Image Classification

Reactive and non-reactive transport modelling in partially water saturated argillaceous porous media around the ventilation experiment,Mont Terri

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Rock Mechanics and Geotechnical Engineering 2013年第1期5卷 44-57页

作者： alexander Bond Steven Benbow James Wilson Alain Millard Shigeo Nakama Myles English christopher McDermott Benoit Garitte Quintessa Ltd. Chadwick House Birchwood Park Warrington Cheshire WA3 6AE UK Commissariat à l'Energie Atomique Japan Atomic Energy Agency (JAEA) University of Edinburgh Universidad Politécnica de Catalunya

At Mont Terri Underground Research Laboratory （URL） Switzerland, a specific experiment has been per- formed in a tunnel, in order to investigate the hydro-mechano-chemical （HMC） perturbations induced in the argillaceous formation by forced ventilation. This experiment has been selected in the international project DECOVALEX to be used for process model development and validation. The numerical simula- tion of the geochemical response to the ventilation experiment （VE） is the object of the present paper, focusing on the transport of chloride as a conservative species and sulphate as a reactive species. Uti- lising the validated hydro-mechanical （HM） results from earlier steps of the DECOVALEX task, reactive and non-reactive transport models, incorporating the current understanding of the geochemistry at the site, were successfully constructed for the whole experimental period. The associated parametric and process uncertainty analyses clearly demonstrate that the basic HM understanding must be sound. How- ever, to demonstrate this degree of robustness, the explicit inclusion of process representations of water desaturation, liquid vaporisation, species exclusion porosity, and redox processes, is required.

关键词： Reactive transportHydro-mechanical (HM) couplingNumerical modellingMont Terri Underground ResearchLaboratory (URL)Ventilation experiment (VE)ArgilliteChlorideSulphate

Particle-Mediated Histotripsy for the Targeted Treatment of Intraluminal Biofilms in Catheter-Based Medical Devices

在线全文

学校读者我要写书评

暂无评论

Biomedical Engineering Frontiers 2022年第1期3卷 367-380页

作者： christopher Childers Connor Edsall Isabelle Mehochko Waleed Mustafa Yasemin Yuksel Durmaz alexander L.Klibanov Jayasimha Rao Eli Vlaisavljevich Virginia Tech Carilion School of Medicine USA Department of Biomedical Engineering and Mechanics Virginia TechUSA Department of Biomedical Engineering Istanbul Medipol UniversityTurkey Division of Cardiovascular Medicine(Department of Medicine)and Robert M.Berne Cardiovascular Research Center at University of Virginia School of Medicine University of VirginiaUSA Department of Medicine Division of Infectious DiseasesVirginia Tech Carilion School of MedicineUSA ICTAS Center for Engineered Health Virginia Polytechnic Institute and State UniversityUSA

*** paper is an initial work towards developing particle-mediated histotripsy(PMH)as a novel method of treating catheter-based medical device(CBMD)intraluminal *** *** commonly become infected with bacterial biofilms leading to medical device failure,infection,and adverse patient *** is a noninvasive focused ultrasound ablation method that was recently proposed as a novel method to remove intraluminal ***,we explore the potential of combining histotripsy with acoustically active particles to develop a PMH approach that can noninvasively remove biofilms without the need for high acoustic pressures or real-time image guidance for *** cavitation thresholds in catheters containing either gas-filled microbubbles(MBs)or fluid-filled nanocones(NCs)were *** ability of these particles to sustain cavitation over multiple ultrasound pulses was tested after a series of histotripsy ***,the ability of PMH to generate selective intraluminal cavitation without generating extraluminal cavitation was ***,the biofilm ablation and bactericidal capabilities of PMH were tested using both MBs and *** significantly reduced the histotripsy cavitation threshold,allowing for selective luminal cavitation for both MBs and *** further showed PMH successfully removed intraluminal biofilms in Tygon ***,results from bactericidal experiments showed minimal reduction in bacteria *** results of this study demonstrate the potential for PMH to provide a new modality for removing bacterial biofilms from CBMDs and suggest that additional work is warranted to develop histotripsy and PMH for treatment of CBMD intraluminal biofilms.

关键词： cavitation remove filled

Development of a Remotely Controlled Testing Platform with Low-drag Air-ventilated Hull

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Marine Science and Application 2015年第1期14卷 25-29页

作者： Konstantin I. Matveev Nicholaus I. Perry alexander W. Mattson christopher S. Chaney School of Mechanical and Materials Engineering Washington State University Pullman WA 99164-2920 USA

这份报纸探讨发展并且有创新的通气空气的壳的一个遥远地控制的船平台严峻。轮船壳的下侧上的空气洞的申请是一答应为减少水动力学的工具拖和污染物质排出物和增加的海洋的交通效率。尽管有这个概念潜力，设计优化和新奇空气洞轮船的高... 详细信息

这份报纸探讨发展并且有创新的通气空气的壳的一个遥远地控制的船平台严峻。轮船壳的下侧上的空气洞的申请是一答应为减少水动力学的工具拖和污染物质排出物和增加的海洋的交通效率。尽管有这个概念潜力，设计优化和新奇空气洞轮船的高效的操作仍然是一个挑战性的问题。赫尔建设和模型规模空气洞船的传感器乐器学在纸被描述。壳的模块化的结构允许容易的修正，和一个电的推进单位启用自己推动的操作。船经由一个收音机传播系统遥远地被控制。起始的测试的结果被报导，包括在几的戳，速度，和气流率装载条件。构造平台能被用于优化空气洞系统并且测试另外的创新的壳图案。这个系统能也被开发进一只高效的无人的船。

关键词：测试平台远程控制低阻力通风空气开发船体结构传输系统

Mechanochemical Difluoromethylations of Alcohols

在线全文

学校读者我要写书评

暂无评论

CCS Chemistry 2023年第8期5卷 1737-1744页

作者： Pit van Bonn Jinbo Ke christopher Weike Jas SWard Kari Rissanen Carsten Bolm Institute of Organic Chemistry RWTH Aachen University52074 Aachen Department of Chemistry University of Jyvaskyla40014 Jyväskylä

Difluoromethyl ethers are formed through mechanochemical reactions of alcohols with difluorocarbene in a mixer *** protocol could be applied to primary,secondary,and tertiary alcohols,yielding the corresponding products in excellent yields(up to 99%)after 1 h reaction time at room *** transformations proceeded under solvent-free reaction conditions,followed by product purification by filtration,which drastically reduced the amount of waste generated during the process.

关键词： mechanochemistry ball milling solventfree reaction difluorocarbene difluoromethyl ether

Copper Delivery by the Copper Chaperone for Chloroplast and Cytosolic Copper/Zinc- Superoxide Dismutases： Regulation and Unexpected Phenotypes in an Arabidopsis Mutant

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Molecular Plant 2009年第6期2卷 1336-1350页

作者： christopher M. Cohu Salah E. Abdel-Ghany Kathryn A. Gogolin Reynolds alexander M. Onofrio Jared R. Bodecker Jeffrey A. Kimbrel Krishna K. Niyogi Marinus Pilon Biology Department Colorado State University Fort Collins CO 80523-1878 USA Department of Plant and Microbial Biology University of California Berkeley CA 94720-3102 USA

Copper （Cu） is an important mineral nutrient found in chloroplasts as a cofactor associated with plastocyanin and Cu/Zn superoxide dismutase （Cu/ZnSOD）. Superoxide dismutases are metallo-enzymes found in most oxygenic organisms with proposed roles in reducing oxidative stress. Several recent studies in Arabidopsis have shown that microRNAs and a SQUAMOSA promoter binding protein-like7 （SPL7） transcription factor function to down-regulate the expression of many Cu-proteins, including Cu/ZnSOD in both plastids and the cytosol, during growth on low Cu. Plants contain the Cu Chaperone for SOD （CCS） that delivers Cu to Cu/ZnSODs, and, in Arabidopsis, both cytosolic and plastidic CCS versions are encoded by one gene. In this study, we demonstrate that Arabiclopsis CCS transcript levels are regulated by Cu, mediated by microRNA 398 that was not previously predicted to target CCS. The microRNA target site is conserved in CCS of Oryza sativa. The data suggest that Cu-regulated microRNAs may have more mRNA targets than was previously predicted. A CCS null mutant has no measurable SOD activity in the chloroplast and cytosol, indicating an absolute requirement for CCS. When the CCS null mutant was grown on high Cu media, it lacked both Fe superoxide dismutase （FeSOD） and Cu/ZnSOD activity. However, this did not lead to a visual phenotype and no photosynthetic deficiencies were detected, even after high light stress. These results indicate that Cu/ZnSOD is not a pivotal component of the photosynthetic anti-oxidant system during growth in laboratory conditions.

关键词： Chloroplast photosynthesis copper homeostasis superoxide dismutase microRNA.

Implementation of New OPAL Tables in Eggleton's Stellar Evolution Code

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Chinese Journal of Astronomy and Astrophysics 2007年第2期7卷 245-250页

作者： Xue-Fei Chen christopher A. Tout National Astronomical Observatories / Yunnan Observatory CAS Kunming 650011 Institute of Astronomy The Observatories Madingley Road Cambridge CB3 0HA England Centre for Stellar and-Planetary Astrophysics Schooi of Mathematics.~Mona-shUniversityClaytonVictoria 3800 Australia

Based on previous works of OPAL, we construct a series of opacity tables for various metaUicities Z = 0, 0.00001, 0,00003, 0.0001, 0.0003, 0.001, 0.004, 0.01, 0.02, 0.03, 0.04, 0.05, 0.06, 0.08 and 0.1. These tables can be easily used in Eggleton＇s stellar evolution code in place of the old tables without changing the code. The OPAL tables are used for log10 （T/K）〉 3.95 and alexander＇s for log10 （T/K）〈 3.95. At log10 （T/K） = 3.95, the two groups＇ data fit well for all hydrogen mass fractions. Conductive opacities are included by reciprocal addition according to the formulae of Yakovlev and Urpin. A comparison of 1 and 5 M⊙ models constructed with the older OPAL tables of Iglesias and Rogers shows that the new opacities have most effect in the late stages of evolution, the extension of the blue loop during helium burning for intermediate-mass and massive stars.

关键词： radiative transfer- stars evolution - stars general

Walking for health during pregnancy:A literature review and considerations for future research

在线全文

学校读者我要写书评

暂无评论

Journal of Sport and Health Science 2019年第5期8卷 401-411页

作者： christopher P.Connolly Scott A.Conger alexander H.K.Montoye Mallory R.Marshall Rebecca A.Schlaff Sylvia E.Badon James M.Pivarnik Kinesiology Program Washington State UniversityPullmanWA 99164-1410USA Department of Kinesiology Boise State UniversityBoiseID 83725USA Department of Integrative Physiology and Health Science Alma CollegeAlmaMI 48801USA Department of Kinesiology Samford UniversityBirminghamAL 35229USA Department of Kinesiology Saginaw Valley State UniversityUniversity CenterMI 48710USA Division of Research Kaiser Permanente Northern CaliforniaOaklandCA 94612USA Department of Kinesiology Michigan State UniversityEast LansingMI 48824-1034USA

Walking is the most commonly chosen type of physical activity(PA)during pregnancy and provides several health benefits to both mother and *** initiatives have promoted the importance of walking in general,but little emphasis is directed toward pregnant women,the majority of whom are insufficiently *** women face a variety of dynamic barriers to a physically active lifestyle,some of which are more commonly experienced during specific times throughout the pregnancy *** is unique in that it appears resistant to a number of these barriers that limit other types of PA participation,and it can be meaningfully integrated into some transportation and occupational activities when leisure-time options are *** intervention work suggests that walking programs can be effectively adopted into a typical pregnancy ***,a great deal of work remains to administer successful pregnancy walking interventions,including developing and using validated methods of PA and walking *** narrative review discusses the unique advantages of walking during pregnancy,provides recommendations for future intervention work,and outlines the need for pregnancy-focused community walking *** search procedures were followed to determine sources from the literature specific to walking during pregnancy for use in each section of this review.

关键词： Ambulatory activity Exercise behavior Maternal-fetal health Pregnant women

First demonstration of an all-solid-state optical cryocooler

在线全文

学校读者我要写书评

暂无评论

Light(Science & Applications) 2018年第1期7卷 922-931页

作者： Markus P.Hehlen Junwei Meng alexander R.Albrecht Eric R.Lee Aram Gragossian Steven P.Love christopher E.Hamilton Richard I.Epstein Mansoor Sheik-Bahae Los Alamos National Laboratory P.O.Box 1663Los AlamosNM 87545USA Department of Physics&Astronomy University of New MexicoAlbuquerqueNM 87131USA

Solid-state optical refrigeration uses anti-Stokes fluorescence to cool macroscopic objects to cryogenic temperatures without *** such as Yb3+-doped YLiF4(YLF:Yb)have previously been laser-cooled to 91 *** this study,we show for the first time laser cooling of a payload connected to a cooling crystal.A YLF:Yb crystal was placed inside a Herriott cell and pumped with a 1020-nm laser(47 W)to cool a HgCdTe sensor that is part of a working Fourier Transform Infrared(FTIR)spectrometer to 135 *** first demonstration of an all-solid-state optical cryocooler was enabled by careful control of the various desired and undesired heat *** heating of the payload was minimized by using a single-kink YLF thermal link between the YLF:Yb cooling crystal and the copper coldfinger that held the HgCdTe *** adhesive-free bond between YLF and YLF:Yb showed excellent thermal *** laser-cooled assembly was then supported by silica aerogel cylinders inside a vacuum clamshell to minimize undesired conductive and radiative heat loads from the warm *** structure can serve as a baseline for future optical cryocooler devices.

关键词： optical pumped desired