检索结果-南通市图书馆

URMG: Enhanced CBMG-Based Method for Automatically Testing Web Applications in the Cloud

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

Tsinghua science and technology 2014年第1期19卷 65-75页

作者： Xiaolin Xu Hai Jin Song Wu Lixiang Tang Yihong Wang Services Computing technology and System Lab and Cluster and Grid Computing Lab School of Computer science and technology Huazhong University of science and technology

To satisfy the rapid growth of cloud technologies, a large number of web applications have been developed and deployed, and these applications are being run in clouds. Due to the scalability provided by clouds, a single web application may be concurrently visited by several millions or billions of users. Thus, the testing and performance evaluations of these applications are increasingly important. User model based evaluations can significantly reduce the manual work required, and can enable us to determine the performance of applications under real runtime environments. Hence, it has become one of the most popular evaluation methods in both industry and academia. Significant efforts have focused on building different kinds of models using mining web access logs, such as Markov models and Customer Behavior Model Graph （CBMG）. This paper proposes a new kind of model, named the User Representation Model Graph （URMG）, which is built based on CBMG. It uses an algorithm to refine CBMG and optimizes the evaluations execution process. Based on this model, an automatic testing and evaluation system for web applications is designed, implemented, and deployed in our test cloud, which is able to execute all of the analysis and testing operations using only web access logs. In our system, the error rate caused by random access to applications in the execution phase is also reduced, and the results show that the error rate of the evaluation that depends on URMG is 50% less than that which depends on CBMG.

关键词： cloud web application performance evaluation customer behavior user representation

Experimental study on the interaction of fine water mist with solid pool fires

在线全文

学校读者我要写书评

暂无评论

science China(Technological sciences) 2003年第2期46卷 218-224页

作者：刘江虹廖光煊厉培德秦俊陆夕云 State Key Laboratory of Fire science University of Science and Technology of China Department of Mechanics & Mechanical Engineering University of Science and Technology of China

This paper describes experimental study of the interaction of fine water mists with solid pool fires. Fine water mist was generated by a single pressure nozzle and solid pool fires were produced from solid red pine or polymethyl methacrylate(PMMA). The LDV/APV system was em-ployed to determine the water mist characteristics. The water mist droplet sizes and velocities from the nozzle were measured under varying conditions and at different locations. The effects of solid type, water flow rate, and nozzle distance from the sample surface on extinguishments time were examined. At a given water flow rate, the extinguishment time is much longer for PMMA fires than for solid pine fires. The extinguishment time was found to decrease with increasing water flow rate. At very low water flow, the extinguishment time decreases when the nozzle is positioned further from the sample surface. On the contrary, at high water flow, the extinguishment time appears to be independent of the distance between the nozzle and the sample surface. The experimental re-sults show that flame extinguishments is due primarily to fuel surface cooling and wetting.

关键词： water mist, solid pool fire, mist characteristics, extinguishment time.

Fault Type Analysis along the San Andreas Fault Zone: A Numerical Approach

在线全文

学校读者我要写书评

暂无评论

Journal of Mountain science 2010年第1期7卷 36-44页

作者： Matrika Prasad KOIRALA Daigoro HAYASHI Simulation Tectonics Laboratory Faculty of Science University of the Ryukyus

Finite Element (FE) modeling under plane stress condition is used to analyze the fault type variation with depth along and around the San Andreas Fault (SAF) zone. In this simulation elastic rheology was used and was thought justifiable as the variation in depth from 0.5 km to 20 km was considered. Series of calculations were performed with the variation in domain properties. Three types of models were created based on simple geological map of California, namely, 1) single domain model considering whole California as one homogeneous domain, 2) three domains model including the North American plate, Pacific plate, and SAF zone as separate domains, and 3) Four domains model including the three above plus the Garlock Fault zone. Mohr-Coulomb failure criterion and Byerlee's law were used for the calculation of failure state. All the models were driven by displacement boundary condition imposing the fixed North American plate and Pacific plate motion along N34°W vector up to the northern terminus of SAF and N50°E vector motion for the subducting the Gorda and Juan de Fuca plates. Our simulated results revealed that as the depth increased, the fault types were generally normal, and at shallow depth greater strike slip and some thrust faults were formed. It is concluded that SAF may be terminated as normal fault at depth although the surface expression is clearly strike slip.

关键词： Finite Element modeling plane stress fault type analysis San Andreas Fault zone rockdomain properties failure analysis

Existence and asymptotic behavior for systems of nonlinear hyperbolic equations

在线全文

学校读者我要写书评

暂无评论

Applied Mathematics(A Journal of Chinese Universities) 2015年第4期30卷 453-465页

作者： YE Yao-jun Department of Mathematics and Information science Zhejiang University of Science and Technology

The initial-boundary value problem for a class of nonlinear hyperbolic equations system in bounded domain is studied. The existence of global solutions for this problem is proved by constructing a stable set, and obta... 详细信息

关键词： Nonlinear hyperbolic equations system global solutions asymptotic behavior difference inequal-ity damping and source terms.

Adsorption of acid fuchsin onto LTA-type zeolite derived from fly ash

在线全文

学校读者我要写书评

暂无评论

science China(Technological sciences) 2014年第6期57卷 1127-1134页

作者： XU HuanYan WU LiCheng SHI TianNuo LIU WeiChao QI ShuYan School of Materials science and Engineering Harbin University of Science and Technology

A facile strategy without organic template was developed for the conversion of fly ash to LTA-type zeolite(LTA-Z),which could be used as a good adsorbent for the removal of acid fuchsin(AF).XRD results indicated that the pure crystalline product was obtained with the structure of LTA-type *** investigations showed that the well-defined LTA-Z crystals exhibited uniform size with the same cubic *** maximum AF adsorption amount was observed at pH=5,slightly lower than pHPZC of *** temperature favored AF adsorption onto LTA-Z and it was an endothermic ***,AF adsorption amount increased with initial AF concentration increasing and LTA-Z dosage *** sorption governed this process at the initial 120 min period,followed by the internal diffusion of AF molecules between porous *** Langmuir model was determined as the adsorption isothermal,suggesting that the monolayer coverage of AF on LTA-Z surface was involved.

关键词： LTA-type zeolite fly ash acid fuchsin kinetics isotherms

Effects of nicotinamide and riboflavin on the biodesulfurization activity of dibenzothiophene by Rhodococcus erythropolis USTB-03

在线全文

学校读者我要写书评

暂无评论

Journal of Environmental sciences 2008年第5期20卷 613-618页

作者： YAN Hai SUN Xudong XU Qianqian MA Zhao XIAO Chengbin Ning Jun Department of Biological science and technology School of Applied Science University of Science and Technology Beijing Beijing 100083 China Research Center for Eco-environmental science Chinese Academy of Sciences Beijing 100085 China

Rhodococcus erythropolis USTB-03 is a promising bacterial strain for the biodesulfurization of dibenzothiophene （DBT） via a sulfurspecific pathway in which DBT is converted to 2-hydroxybiphenyl （2HBP） as an end product. The effects of nicotinamide and riboflavin on the sulfur specific activity （SA） of DBT biodesulfurization by R. erythropolis USTB-03 were investigated. Both nicotinamide and riboflavin were found to enhance the expression of SA, which was not previously reported. When R. erythropolis USTB-03 was grown on a medium containing nicotinamide of 10.0 mmol or riboflavin of 50.0 μmol, SA was raised from 68.0 or so to more than 130 mmol 2HBP/（kg dry cells.h）. When R. erythropolis USTB-03 was grown in the presence of both nicotinamide of 5.0 mmol and riboflavin of 25.0 μmol, SA was further increased to 159.0 mmol 2HBP/（kg dry cells.h）. It is suggested that the biological synthesis of reduced form of flavin mononucleotide （FMNH2）, an essential coenzyme for the activities of biodesulfurization enzyme Dsz C and A, might be enhanced by nicotinamide and riboflavin, which was responsible for the increased SA of R. erythropolis USTB-03.

关键词： biodesulfurization dibenzothiophene nicotinamide Rhodococcus erythropolis USTB-03 riboflavin

Influence of wet chemical cleaning on quantum efficiency of GaN photocathode

在线全文

学校读者我要写书评

暂无评论

Chinese Physics B 2013年第2期22卷 515-518页

作者：王晓晖高频王洪刚李飙常本康 Institute of Electronic Engineering and Optoelectronic technology Nanjing University of Science and Technology

GaN samples 1-3 are cleaned by a 2：2：1 solution of sulfuric acid（98%） to hydrogen peroxide（30%） to de-ionized water;hydrochloric acid（37%）;or a 4：1 solution of sulfuric acid（98%） to hydrogen peroxide（30%）.The samples are activated by Cs/O after the same annealing process.X-ray photoelectron spectroscopy after the different ways of wet chemical cleaning shows：sample 1 has the largest proportion of Ga,N,and O among the three samples,while its C content is the *** activation the quantum efficiency curves show sample 1 has the best photocathode *** think the wet chemical cleaning method is a process which will mainly remove C contamination.

关键词： GaN photocathode X-ray photoelectron spectroscopy wet chemical cleaning quantum efficiency

Effect of austenitization heat treatment on the magnetic properties of Fe-40wt%Ni-2wt%Mn alloy

在线全文

学校读者我要写书评

暂无评论

Journal of University of science and technology Beijing 2007年第4期14卷 327-330页

作者： S. Buyukakkas H. Aktas S. Akturk Department of Physics Science and Arts Faculty of Nigde University Nigde Turkey Department of Physics Science and Arts Faculty of Kirikkale University Yahsihan 71450 Kirikkale Turkey

The effect of austenitization heat treatment on magnetic properties was examined by means of M6ssbauer spectroscopy on an Fe-40wt%Ni-2wt%Mn alloy. The morphology of the alloy was obtained by using scanning electron microscopy （SEM） under different heat treatment conditions. The magnetic behavior of the non heat-treated alloy is ferromagnetic. A mixed magnetic structure including both paramagnetic and ferromagnetic states was obtained at 800℃ after 6 and 12 h heat treatments. In addition, the magnetic structure of the heat-treated alloy at 1150~C for 12 h was ferromagnetic. With the volume fraction changing, the effective hyperfine field of the ferromagnetic austenite phase and isomery shift values were also determined by Mtssbauer spectroscopy.

关键词： Mossbauer spectroscopy scanning electron microscopy dentrite ferromagnetic austenite

On Learning Adaptive Service Compositions

在线全文

学校读者我要写书评

暂无评论

Journal of Systems science and Systems Engineering 2021年第4期30卷 465-481页

作者： Ahmed Moustafa Department of Computer science Nagoya Institute of TechnologyGokiso-choShowa-kuNagoyaAichi466-8555Japan faculty of Informatics Zagazig UniversityZagazigEgypt

Service composition is an important and effective technique that enables atomic services to be combined together to forma more powerful service,i.e.,a composite *** the pervasiveness of the Internet and the proliferation of interconnected computing devices,it is essential that service composition embraces an adaptive service provisioning *** learning has emerged as a powerful tool to compose and adapt Web services in open and dynamic ***,the most common applications of reinforcement learning algorithms are relatively inefficient in their use of the interaction experience data,whichmay affect the stability of the learning process when deployed to cloud *** particular,they make just one learning update for each interaction *** paper introduces a novel approach that aims to achieve greater data efficiency by saving the experience data and using it in aggregate to make updates to the learned *** proposed approach devises an offline learning scheme for cloud service composition where the online learning task is transformed into a series of supervised learning tasks.A set of algorithms is proposed under this scheme in order to facilitate and empower efficient service composition in the cloud under various policies and different *** results of our experiments show the effectiveness of the proposed approach for composing and adapting cloud services,especially under dynamic environment settings,compared to their online learning counterparts.

关键词： Service composition reinforcement learning cloud services offline learning