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Towards Cost-Effective Cloud Downloading with Tencent Big Data

Journal of Computer Science & Technology 2015年第6期30卷 1163-1174页

作者：李振华刘刚嵇智源 Roger zimmermann School of Software Tsinghua University Beijing 100084 China Tsinghua National Laboratory for Information Science and Technology Beijing 100084 China QQXuanfeng System Group Tencent Co. Ltd Shanghai 200233 China High Technology Research and Development Center Ministry of Science and Technology Beijing 10004 China Department of Computer Science National University of Singapore Singapore 117417 Singapore

The cloud downloading scheme, first proposed by us in 2011, has effectively optimized hundreds of millions of users＇ downloading experiences. Also, people start to build a variety of useful Internet services on top of cloud downloading. In brief, by using cloud facilities to download （and cache） the requested file from the ＂best-effort＂ Internet on behalf of the user, cloud downloading ensures the data availability and remarkably enhances the data delivery speed. Although this scheme seems simple and straightforward, designing a real-world cloud downloading system involves complicated and subtle trade-offs （between deployment cost and user experience） when serving a large number of users： 1） how to plan the cloud cache capacity to achieve a high and affordable cache hit ratio, 2） how to accelerate the data delivery from the cloud to numerous users, 3） how to handle the dense user requests for highly popular files, and 4） how to judge a potential downloading failure of the cloud. This paper addresses these design trade-offs from a practical perspective, based on big data from a nationwide commercial cloud downloading system, i.e., Tencent QQXuanfeng. Its running traces help us find reasonable design strategies and parameters, and its real performances confirm the efficacy of our design. Our study provides solid experiences and valuable heuristics for the developers of similar and relevant systems.

关键词： cloud downloading cost-effective design trade-off big data

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ACCELERATOR PHYSICS OF COLLIDERS

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Chinese Physics C 2016年第10期40卷 429-434页

作者： m.J. Syphers F. zimmermann NIU/FNAL CERN

30.1. Luminosity This article provides background for the High-Energy Collider Parameter Tables that follow. The number of events, Nexp, is the product of the cross section of interest, aexp, and the time integral ove...

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Turning of aluminum metal matrix composites： influence of the reinforcement and the cutting condition on the surface layer of the workpiece

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Advances in manufacturing 2016年第3期4卷 225-236页

作者： Jan C. Aurich marco zimmermann Stefan Schindler Paul Steinmann Institute for manufacturing Technology and ProductionSystems University of Kaiserslautern KaiserslauternGermany Chair of Applied mechanics University of Erlangen-Nuremberg Erlangen Germany

Aluminum metal matrix composites （Al-mmCs） are difficult to machine. The reinforcement of aluminum using ceramic particles accelerates tool wear. moreover, demanded machining accuracies or properties of the surface layer are difficult to achieve. In the present study, the effect of silicon carbide reinforcement particles on the surface layer of the workpiece was investigated using multiple cutting conditions for dry turning. Three differently reinforced Al-mmCs regarding the volume percent-age （17% and 30%） and the particle size （0.6 μm and 3 μm） and their non-reinforced matrix were considered as the workpiece materials. The reinforcement and the cutting condition affect the results of turning. A greater particle volume percent improves the surface roughness and decreases the tensile stress in the surface. The smaller particle size caused a lower tensile stress in the surface. A general effect of the particle size on the workpiece roughness can not be concluded. The most important cutting parameter for the surface layer of the workpiece is the feed. Greater feeds decrease the tensile stress in the surface, but deteriorate the surface quality.

关键词： Aluminum metal matrix composite(Al-mmC) Forces . Workpiece roughness Surface Residual stress

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Optimizing the size of the area surveyed for monitoring a Eurasian lynx(Lynx lynx)population in the Swiss Alps by means of photographic capture–recapture

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Integrative Zoology 2013年第3期8卷 232-243页

作者： Fridolin zimmermann Christine BREITENmOSER-WÜRSTEN Anja mOLINARI-JOBIN Urs BREITENmOSER KORA MuriSwitzerland Institute of Veterinary Virology University of BernBernSwitzerland

We studied the influence of surveyed area size on density estimates by means of camera-trapping in a low-density felid population(1-2 individuals/100 km^(2)).We applied non-spatial capture-recapture(CR)and spatial CR(SCR)models for Eurasian lynx during winter 2005/2006 in the northwestern Swiss Alps by sampling an area divided into 5 nested plots ranging from 65 to 760 km^(2).CR model density estimates(95%CI)for models m_(0)and m_(h)decreased from 2.61(1.55-3.68)and 3.6(1.62-5.57)independent lynx/100 km^(2),respectively,in the smallest to 1.20(1.04-1.35)and 1.26(0.89-1.63)independent lynx/100 km^(2),respectively,in the largest area *** model density estimates also decreased with increasing sampling area but not *** individual range overlaps in relatively small areas(the edge effect)is the most plausible reason for this positive bias in the CR *** results confirm that SCR models are much more robust to changes in trap array size than CR models,thus avoiding overestimation of density in smaller ***,when a study is concerned with monitoring population changes,large spatial efforts(area surveyed≥760 km^(2))are required to obtain reliable and precise density estimates with these population densities and recapture rates.

关键词： area surveyed density estimation Lynx lynx photographic capture-recapture Swiss Alps

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Statistical analyses of Global U-Pb Database 2017

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Geoscience Frontiers 2018年第1期9卷 121-145页

作者： Stephen J.Puetz Carlos E.Ganade Udo zimmermann Glenn Borchardt Progressive Science Institute HonoluluHI 96815USA Geological Survey of Brazil Rio de JaneiroBrazil University of Stavanger Department of Petroleum EngineeringStavangerNorway Progressive Science Institute Box 5335BerkeleyCA 94705USA

The method of obtaining zircon samples affects estimation of the global U-Pb age *** typically collect zircons via convenience sampling and cluster *** using these techniques,weight adjustments proportional to the areas of the sampled regions improve upon unweighted ***,grid-area and modern sediment methods are used to weight the samples from a new database of 418,967 U-Pb *** tests involve two age ***-1 uses the most precise U-Pb ages as the best ***-2 uses the^(206)Pb/^(238)U age as the best age if it is less than a1000 ma cutoff,otherwise it uses the^(207)Pb/^(206)Pb age as the best age.A correlation analysis between the model-1 and model-2 ages indicates nearly identical distributions for both ***,after applying acceptance criteria to include only the most precise analyses with minimal discordance,a histogram of the rejected samples shows excessive rejection of the model-2 analyses around the1000 ma cutoff *** of the excessive rejection rate for model-2,we select model-1 as the preferred *** eliminating all rejected samples,the remaining analyses use only model-1 ages for five rock-type subsets of the database:igneous,meta-igneous,sedimentary,meta-sedimentary,and modern ***,time-series plots,cross-correlation analyses,and spectral analyses determine the degree of alignment among the time-series and their *** all rock types,the U-Pb age distributions are similar for ages older than 500 ma,but align poorly for ages younger than 500 *** similarities(>500 ma)and differences(ma)highlight how reductionism from a detailed database enhances understanding of time-dependent sequences,such as erosion,detrital transport mechanisms,lithification,and ***-series analyses and spectral analyses of the age distributions predominantly indicate a synchronous period-tripling sequence of^91-myr,~273-myr,and^819-myr among the various rock typ

关键词： Time series Spectral analysis Periodicity Sampling Reductionism Zircon

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Pyrimidine metabolism: Dynamic and Versatile Pathways in Pathogens and Cellular Development

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Journal of Genetics and Genomics 2015年第5期42卷 195-205页

作者： manuel F.Garavito Heidy Y.Narváez-Ortiz Barbara H.zimmermann Department of Biological Sciences Los Andes University

The importance of pyrimidines lies in the fact that they are structural components of a broad spectrum of key molecules that participate in diverse cellular functions, such as synthesis of DNA, RNA, lipids, and carbohydrates. Pyrimidine metabolism encompasses all enzymes involved in the synthesis, degradation, salvage, interconversion and transport of these molecules. In this review, we summarize recent publications that document how pyrimidine metabolism changes under a variety of conditions, including, when possible, those studies based on techniques of genomics, transcriptomics, proteomics, and metabolomics. First, we briefly look at the dynamics of pyrimidine metabolism during nonpathogenic cellular events. We then focus on changes that pathogen infections cause in the pyrimidine metabolism of their host. Next, we discuss the effects of antimetabolites and inhibitors, and finally we consider the consequences of genetic ma- nipulations, such as knock-downs, knock-outs, and knock-ins, of pyrimidine enzymes on pyrimidine metabolism in the cell.

关键词： Pyrimidine metabolism Pathogens CAD Dihydroorotase Dihydroorotate dehydrogenase UmP synthase

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Dual-polarization multiplexing amorphous Si:H grating couplers for silicon photonic transmitters in the photonic BiCmOS backend of line

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Frontiers of Optoelectronics 2022年第1期15卷 143-155页

作者： Galina Georgieva Christian mai Pascal m.Seiler Anna Peczek Lars zimmermann Hochfrequenztechnik-Photonik/Siliziumphotonik Technische Universität BerlinStraße des 17.Juni 13510623 BerlinGermany IHP-Leibnitz Institut für innovative mikroelektronik Im Technologiepark 2515236 Frankfurt(Oder)Germany IHP Solutions GmbH Im Technologiepark 715236 Frankfurt(Oder)Germany

In this paper,we report on polarization combining two-dimensional grating couplers(2D GCs)on amorphous Si:H,fabricated in the backend of line of a photonic BiCmOS *** 2D GCs can be used as an interface of a hybrid silicon photonic coherent transmitter,which can be implemented on bulk Si *** fabricated 2D GCs operate in the telecom C-band and show an experimental coupling efficiency of−5 dB with a wafer variation of±1.2 *** for efficiency enhancement and improved performance stability in future design generations are outlined and extension toward O-band devices is also investigated.

关键词： Hybrid integration Photonic BiCmOS Amorphous silicon Two-dimensional grating coupler(2D GC) Dual-polarization coherent communication Silicon photonics

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modelling the long-term geomorphic response to check dam failures in an alpine channel with CAESAR-Lisflood

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International Journal of Sediment Research 2022年第5期37卷 687-700页

作者： Jorge Alberto Ramirez mirjam mertin Nadav Peleg Pascal Horton Chris Skinner m.rkus zimmermann margreth Keiler Institute of Geography University of Bern Oeschger Centre for Climate Change Research University of Bern Institute of Environmental Engineering ETH Zurich Institute of Earth Surface Dynamics University of Lausanne Energy and Environment Institute University of Hull Department of Geography University of Innsbruck Institute for Interdisciplinary mountain Research Austrian Academy of Sciences

Globally, between 1950 and 2011 nearly 80,000 debris flow fatalities occurred in densely populated regions in mountainous terrain. mitigation of these hazards includes the construction of check dams,which limit coarse sediment transport and in the European Alps number in the 100,000s. Check dam functionality depends on periodic, costly maintenance, but maintenance is not always possible and check dams often fail. As such, there is a need to quantify the long-term(10-100 years) geomorphic response of rivers to check dam failures. Here, for the first time, a landscape evolution model(CAESARLisflood) driven by a weather generator is used to replicate check dam failures due to the lack of maintenance, check dam age, and flood occurrence. The model is applied to the Guerbe River,Switzerland, a pre-Alpine catchment containing 73 check dams that undergo simulated failure. Also presented is a novel method to calibrate CAESAR-Lisflood?s hydrological component on this ungauged catchment. Using 100-year scenarios of check dam failure, the model indicates that check dam failures can produce 8 m of channel erosion and a 322% increase in sediment yield. The model suggests that after check dam failure, channel erosion is the remobilization of deposits accumulated behind check dams, and, after a single check dam failure channel equilibrium occurs in five years, but after many check dam failures channel equilibrium may not occur until 15 years. Overall, these findings support the continued maintenance of check dams.

关键词： Landscape evolution model Check dam failure Weather generator Natural hazards

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Pre-operative total parenteral nutrition improves post-operative outcomes in a subset of Crohn’s disease patients undergoing major abdominal surgery

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Gastroenterology Report 2019年第2期7卷 107-114,I0002页

作者： Fares Ayoub Amir Y.Kamel Ahmed Ouni Naueen Chaudhry Yan Ader Sanda Tan Atif Iqbal Ellen m.zimmermann Sarah C.Glover Department of medicine University of FloridaGainesvilleFLUSA Department of Pharmacy University of FloridaGainesvilleFLUSA Division of Gastroenterology Hepatology&NutritionDepartment of MedicineUniversity of FloridaGainesvilleFLUSA Department of Surgery University of FloridaGainesvilleFLUSA

Background:Despitemajor advances in themedicalmanagement of Crohn’s disease(CD),a significant proportion of patients will require surgery within 5 years of *** is an independent risk factor for adverse post-operative outcomes following gastrointestinal *** on the value of pre-operative total parenteral nutrition(TPN)in CD patients aremixed and there is a paucity of data in the biologic *** aimed to define the role of pre-operative TPN in this ***:This was a retrospective cohort study conducted at a tertiary referral *** patients who underwent major abdominal surgery were *** receiving pre-operative TPN were compared to *** compared the incidence of 30-day infectious and non-infectious post-operative complications between the two ***:A total of 144 CD patients who underwent major abdominal surgery between march 2007 and march 2017 were ***-five patients who received pre-operative TPN were compared to 89 ***-one(14.6%)patients developed infectious complications(18.2%in TPN group vs 12.3%in non-TPN group,P=0.34)and 23(15.9%)developed noninfectious complications(14.5%in TPN group vs 16.9%in non-TPN group,P=0.71).In a multivariate analysis,controlling for differences in baseline disease severity and malnutrition between groups,patients receiving pre-operative TPN for60 days had significantly lower odds of developing non-infectious complications(odds ratio 0.07,95%confidence interval:0.01–0.80,P=0.03).Weight loss of>10%in the past 6 months was a significant predictor of post-operative ***:In a subset of malnourished CD patients,TPN is safe and allows comparable operative outcomes to ***-operative TPN for60 days reduced post-operative non-infectious complications without associated increase in infectious complications.

关键词： Crohn’s disease total parenteral nutrition pre-operative malnutrition post-operative complications

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Fractional Flow Reserve-guided Percutaneous Coronary Intervention:Standing the Test of Time

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Cardiovascular Innovations and Applications 2016年第B5期1卷 225-232页

作者： Frederik m.zimmermann Lokien X.van Nunen Department of Cardiology Catharina Hospital EindhovenEindhovenThe Netherlands

Percutaneous coronary intervention(PCI)improves symptoms and prognosis in ischemia-inducing,functionally signifi cant,coronary *** of fractional flow reserve allows physicians to investigate the ischemia-inducing potential of a specifi c lesion and can be used to guide coronary revascularization,especially in multivessel coronary artery *** flow reserve-guided PCI has been extensively *** show that deferral of stenting in non-signifi cant lesions is safe,whereas deferral of stenting in functionally signifi cant lesions worsens ***-guided PCI improves outcome in multivessel disease over angiography-guided *** recently,there was little known about the long-term outcome of FFR-guided revascularization and its validity in acute coronary *** review aims to address the new evidence regarding long-term appropriateness of FFR-guided PCI,the need for hyperemia to evaluate functional severity,and the use of FFR in acute coronary syndromes.

关键词： coronary artery disease percutaneous coronary intervention fractional flow reserve

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