检索结果-南通市图书馆

Performance analysis of parallel gravitational N-body codes on large GPU clusters

Research in Astronomy and Astrophysics 2016年第1期16卷 89-100页

作者： Si-Yi Huang rainer Spurzem Peter Berczik National Astronomical Observatories and Key Laboratory of Computational Astrophysics Chinese Academy of Sciences Beijing 100012 China Kavli Institute for Astronomy and Astrophysics Peking University Beijing 100871 China Main Astronomical Observatory Ukrainian National Academy of Sciences 03680 Kiev Ukraine Astronomisches Rechen-Institut Zentrum fur Astronomie Universitat Heidelberg 69120 Heidelberg Germany

we compare the performance of two very different parallel gravitational N-body codes for astrophysical simulations on large Graphics Processing Unit（GPU） clusters, both of which are pioneers in their own fields as well as on certain mutual scales- NBODY6＋＋ and Bonsai. we carry out benchmarks of the two codes by analyzing their performance, accuracy and efficiency through the modeling of structure decomposition and timing measurements. we find that both codes are heavily optimized to leverage the computational potential of GPUs as their performance has approached half of the maximum single precision performance of the underlying GPU cards. with such performance we predict that a speed-up of200- 300 can be achieved when up to 1k processors and GPUs are employed simultaneously. we discuss the quantitative information about comparisons of the two codes, finding that in the same cases Bonsai adopts larger time steps as well as larger relative energy errors than NBODY6＋＋, typically ranging from10- 50 times larger, depending on the chosen parameters of the codes. Although the two codes are built for different astrophysical applications, in specified conditions they may overlap in performance at certain physical scales, thus allowing the user to choose either one by fine-tuning parameters accordingly.

关键词： methods: analytical -- methods: data analysis -- methods: numerical

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Climate Change, Risk and Grain Yields in China

引用

Journal of Integrative Agriculture 2013年第7期12卷 1279-1291页

作者： rainer Holst Xiaohua Yu Carola Grün Courant Research Center 'Poverty Equity and Growth' Georg-August-University of Goettingen world Bank

Adopting Just and Pope （1978, 1979） style yield functions, this paper proposes a method to analyze the impacts of regional climate change on grain production in China. we find that changes in climate will affect grain production in North and South China differently. Specifically, it emerges that a 1℃ increase in annual average temperature could reduce national grain output by 1.45% （1.74% reduction in North China and 1.19% reduction in South China）, while an increase in total annual precipitation of around 100 mm could increase national grain output by 1.31% （3.0% increase in North China and 0.59% reduction in South China）.

关键词： grain yield climate change yield risk China

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Low-loss optical waveguides made with a high-loss material

引用

Light(Science & Applications) 2021年第1期10卷 12-18页

作者： Darius Urbonas rainer F.Mahrt Thilo Stoferle IBM Research Europe—Zurich Saumerstrasse 48803 RuschlikonSwitzerland

For guiding light on a chip,it has been pivotal to use materials and process flows that allow low absorption and *** on subwavelength gratings,here,we show that it is possible to create broadband,multimode waveguides with very low propagation losses despite using a strongly absorbing *** perform rigorous coupled-wave analysis and finite-difference time-domain simulations of integrated waveguides that consist of pairs of integrated high-index-contrast *** showcase this concept,we demonstrate guiding of visible light in the wavelength range of 550-650 nm with losses down to 6dB/cm using silicon gratings that have a material absorption of 13,000 dB/cm at this wavelength and are fabricated with standard silicon photonics *** approach allows us to overcome traditional limits of the various established photonics technology platforms with respect to their suitable spectral range and,furthermore,to mitigate situations where absorbing materials,such as highly doped semiconductors,cannot be avoided because of the need for electrical driving,for example,for amplifiers,lasers and modulators.

关键词： waveguides absorbing absorption

来源：

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Level of education and mortality after radical prostatectomy

引用

Asian Journal of Andrology 2017年第2期19卷 173-177页

作者： Michael Froehner rainer Koch Stefan Propping Dorothea Liebeheim Matthias Hfibler Gustavo B Baretton Oliver w Hakenberg Manfred P wirth Department of Urology University Hospital 'Carl Gustav Carus' Technische Universit~t Dresden Fetscherstrasse 74 D-01307 Dresden Germany Department of Medical Statistics and Biometry University Hospital 'Carl Gustav Carus' Technische Universitat Dresden Fetscherstrasse 74 D-01307 Dresden Germany Department of Anesthesiology University Hospital 'Carl Gustav Carus' Technische Universitat Dresden Fetscherstrasse 74 D-01307 Dresden Germany Department of Pathology University Hospital 'Carl Gustav Carus' Technische Universitat Dresden Fetscherstrasse 74 D-01307 Dresden Germany Department of Urology University of Rostock Ernst-Heydemann-Strasse 6 D-18055 Rostock Germany

Estimating the risk of competing mortality is of importance in men with early prostate cancer to choose the most appropriate way of management and to avoid over- or under-treatment. In this study, we investigated the impact of the level of education in this context. The study sample consisted of 2630 patients with complete data on level of education （college, university degree, master craftsmen, comparable profession, or others）, histopathological tumor stage （organ confined or extracapsular）, lymph node status （negative or positive）, and prostatectomy specimen Gleason score （〈7, 7, or 8-10） who underwent radical prostatectomy between 1992 and 2007. Overall, prostate cancer-specific, competing, and second cancer-related mortalities were study endpoints. Cox proportional hazard models for competing risks were used to study combined effects of the variables on these endpoints. A higher level of education was independently associated with decreased overall mortality after radical prostatectomy （hazard ratio [HR]： 0.75, 95% confidence interval [95% CI]： 0.62-0.91, P = 0.0037）. The mortality difference was attributable to decreased second cancer mortality （HR： 0.59, 95% Ch 0.40-0.85, P = 0.0052） and noncancer mortality （HR： 0.73, 95% Ch 0.55-0.98, P = 0.0345） but not to differences in prostate cancer-specific mortality （HR： 1.16, 95% Ch 0.79-1.69, P = 0.4536 in the full model）. In conclusion, the level of education might serve as an independent prognostic parameter supplementary to age, comorbidity, and smoking status to estimate the risk of competing mortality and to choose optimal treatment for men with early prostate cancer who are candidates for radical prostatectomy.

关键词： comorbidity competing risk analysis level of education life expectancy mortality proportional hazards model prostate cancer radical prostatectomy smoking socioeconomic status

来源：

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

3omorbidity and survival of patients selected for radica prostatectomy at an age of 75 years or older

引用

Asian Journal of Andrology 2013年第5期15卷 667-671页

作者： Michael Froehner rainer Koch Manfred P wirth Departments of Urology University Hospital 'Carl Gustav Carus' Dresden University of Technology Dresden D-01307 Germany Department of Medical Statistics and Biometry University Hospital 'Carl Gustav Carus' Dresden University of Technology Dresden D-01307 Germany

Radical prostatectomy in elderly patients is controversial. To identify very old candidates for radical prostatectomy with the highest probability of long-term survival, we studied 47 consecutive men who underwent radical prostatectomy between 1992 and 2005 at an age of 75 years or older. A heuristic approach was used to search for subgroups with particularly high long-term survival. Several two-sided comorbidity measures and combinations of these measures were investigated to find classifications best identifying healthy, long-living elderly candidates for radical prostatectomy. Four of the 25 two-sided comorbidity classifications or combinations reached the significance level with hazard ratios between 4.00 and 4.80. After 10 years, patients identified as healthy patients according to these comorbidity measurements had exhibited relative survival rates between 129% and 137% and overall survival rates between 86% and 95%, whereas those with comorbidities had exhibited relative survival rates of only 66%-84% and overall survival rates of 44%-58%. In conclusion, classifying comorbidity may identify a meaningful proportion of men selected for radical prostatectomy at an age of 75 years or older with an excellent long-term survival probability superseding that of the general population.

关键词： comorbidity old age overall survival prostate cancer radical prostatectomy relative survival

来源：

维普期刊数据库评论

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 Dynamics Study of a Thermal Expansion Coefficient： Ti Bulk with an Elastic Minimum image Method

引用

Chinese Physics Letters 2006年第5期23卷 1068-1071页

作者： Yakup Hundur rainer Hippler Ziya B. Güven Department of Physics Istanbul Technical University Ayazaga Istanbul TR-34469 Turkey Institut für Physik Ernst-Moritz-Arndt-Universitat Greifswald DomstraBe 10a D-17487 Greifswald. Germany Electronic and Communication Engineering Cankaya University Balgat Ankara TR-06530 Turkey

Linear thermal expansion coefficient （TEC） of Ti bulk is investigated by means of molecular dynamics simulation. The elastic minimum image convention of periodic boundary conditions is introduced to allow the bulk to adjust its size according to the new fixed temperature. The TEC and the specific heat of Ti are compared to the available theoretical and experimental data.

关键词： TITANIUM

来源：

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Effects of substrate surface treatments on hybrid manufacturing of AlSi7Mg using die casting and selective laser melting

引用

Journal of Materials Science & Technology 2023年第25期156卷 142-156页

作者： Haiyang Fan Ann witvrouw Friedrich wolf-Monheim rainer Souschek Shoufeng Yang Department of Mechanical Engineering and Flanders Make KU LeuvenCelestijnenlaan 300Bbox 2420HeverleeB-3001 LeuvenBelgium Ford Research & Advanced Engineering Ford Research and Innovation Center AachenSüsterfeldstraße 20052072 AachenGermany Yantai Research Institute Harbin Engineering University264000 YantaiChina

To balance the manufacturing cost and customizability of automotive parts,a hybrid manufacturing process combining die-casting and selective laser melting(SLM)is proposed:starting with a conventional cast substrate,SLM is utilized to add additional geometric elements on top of *** this hybrid process,the first priority is to prepare a substrate surface suitable for the subsequent SLM addition of the top-on *** this study,the original cast surface of AlSi7Mg was processed by sandblasting,wire electro-discharge machining,and laser remelting,***,additional AlSi7Mg components were built on both the original cast and treated surfaces through *** hybrid builds,these surfaces and resultant interfaces were examined by optical and scanning electron *** indicate that the defect-free metallurgical joint between the cast and additively added parts can be formed on all surfaces except for the one processed by electro-discharge *** observed epitaxial grain growth crossing the interface implies a strong connection between the cast and the SLMed *** these benefits,also mismatches in microstructure,residual stress level and element distribution between the two parts are *** a comprehensive assessment,laser remelting with no additional machining is recommended as the optimal surface treatment preceding SLM fabrication,because of its user-friendly operation,low cost,and high industrial feasibility.

关键词： Hybrid manufacturing Aluminium alloy Surface treatment Laser remelting Interface Automotive

来源：

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

尼泊尔西部传统医学、药用植物及市场管理现状

引用

亚太传统医药 2020年第2期16卷 1-2页

作者： Ripu M Kunwar Laxmi Mahat Ram P Acharya rainer w.bussmann 佛罗里达亚特兰大大学美国佛罗里达特里布文大学尼泊尔加德满都南昆士兰大学澳大利亚昆士兰伊利亚州立大学格鲁吉亚第比利斯

现代医学是以本土疗法和民族药理学等传统医药学为基础逐渐发展而来的,而传统医药学也成为寻找新药和新的疾病治疗方法的重要来源。医疗全球化的进程使人们对传统医药的需求越来越多,加之不合理的开采和不规范的保护措施,尼泊尔的许多... 详细信息

现代医学是以本土疗法和民族药理学等传统医药学为基础逐渐发展而来的,而传统医药学也成为寻找新药和新的疾病治疗方法的重要来源。医疗全球化的进程使人们对传统医药的需求越来越多,加之不合理的开采和不规范的保护措施,尼泊尔的许多药用植物资源濒临灭绝,可持续化管理迫在眉睫。虽然现代医学对传统医学的冲击很大,但尼泊尔当地居民对传统医学的需求从未停止,除了使用其进行治病外,还通过种植、采集和销售等途径获取经济效益,因此传统医药的规范化管理也应提上日程。

关键词：尼泊尔药用植物可持续管理

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Could a phase model help to improve translational animal research?

引用

Animal Models and Experimental Medicine 2022年第6期5卷 550-556页

作者： Benjamin Mayer Jan Tuckermann rainer Muche Institute of Epidemiology and Medical Biometry Ulm UniversityUlmGermany Institute of Comparative Molecular Endocrinology Ulm UniversityUlmGermany

Background:Animal models are widely applied in medical research for different *** particular,results from translational experiments may be used for subsequent clinical ***,transferability of these findings to the human organism is *** other factors,this may be traced back to a lack of clear differentiation of the evidence(explorative ***)provided by such experimental *** general,inferential statistics(i.e.p values)should not be interpreted in as confirmatory unless crucial methodological requirements are ***:Therefore,we propose a phase model which reflects the well-established process of clinical research,and we discuss its potential to improve decision making in translational *** model aims to clarify the reliability of results derived from animal ***:The phase model proposes subdividing translational,pre-clinical research into pilot,exploration,and confirmation *** for which there is no valid estimation of the expected effect size are designated as pilot *** on these data,experiments in subsequent phases may be planned using both appropriate design and statistical ***:Separating the entire process of translational animal research into three phases could contribute to improved transparency of the evidence derived from such experiments.

关键词： confirmatory trials hypothesis testing results interpretation transferability

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

A spatially-explicit count data regression for modeling the density of forest cockchafer(Melolontha hippocastani) larvae in the Hessian Ried(Germany)

引用

Forest Ecosystems 2014年第4期1卷 185-200页

作者： Matthias Schmidt rainer Hurling The Northwest German Forest Research Station

Background： In this paper, a regression model for predicting the spatial distribution of forest cockchafer larvae in the Hessian Ried region （Germany） is presented. The forest cockchafer, a native biotic pest, is a major cause of damage in forests in this region particularly during the regeneration phase. The model developed in this study is based on a systematic sample inventory of forest cockchafer larvae by excavation across the Hessian Ried. These forest cockchafer larvae data were characterized by excess zeros and overdispersion. Methods： Using specific generalized additive regression models, different discrete distributions, including the Poisson, negative binomial and zero-inflated Poisson distributions, were compared. The methodology employed allowed the simultaneous estimation of non-linear model effects of causal covariates and, to account for spatial autocorrelation, of a 2-dimensional spatial trend function. In the validation of the models, both the Akaike information criterion （AIC） and more detailed graphical procedures based on randomized quantile residuals were used. Results： The negative binomial distribution was superior to the Poisson and the zero-inflated Poisson distributions, providing a near perfect fit to the data, which was proven in an extensive validation process. The causal predictors found to affect the density of larvae significantly were distance to water table and percentage of pure clay layer in the soil to a depth of I m. Model predictions showed that larva density increased with an increase in distance to the water table up to almost 4 m, after which it remained constant, and with a reduction in the percentage of pure clay layer. However this latter correlation was weak and requires further investigation. The 2-dimensional trend function indicated a strong spatial effect, and thus explained by far the highest proportion of variation in larva density. Conclusions： As such the model can be used to support forest practitioners in thei

关键词： Forest cockchafer Larvae Negative binomial distribution Poisson distribution Zerc〉-inflated poissondistribution Systematic sample inventory Generalized additive model Spatial autocorrelation Randomizedquantile residuals

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

欢迎您,

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案：

请选择收藏分类：

通借通还

欢迎您,

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：