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1.
Load testing of applications is an important and costly activity for software provider companies. Classical solutions are very difficult to set up statically, and their cost is prohibitive in terms of both human and hardware resources. Virtualized cloud computing platforms provide new opportunities for stressing an application's scalability, by providing a large range of flexible and less expensive (pay‐per‐use model) computation units. On the basis of these advantages, load testing solutions could be provided on demand in the cloud. This paper describes a Benchmark‐as‐a‐Service solution that automatically scales the load injection platform and facilitates its setup according to load profiles. Our approach is based on: (i) virtualization of the benchmarking platform to create self‐scaling injectors; (ii) online calibration to characterize the injector's capacity and impact on the benched application; and (iii) a provisioning solution to appropriately scale the load injection platform ahead of time. We also report experiments on a benchmark illustrating the benefits of this system in terms of cost and resource reductions. Copyright © 2013 John Wiley & Sons, Ltd. 相似文献
2.
Minh Lequan Rose Marie Lequan Kathleen Chane-ching Anne-claude Callier Marguerite Barzoukas Alain Fort 《Advanced functional materials》1992,1(5):243-247
Samples of {4-(dimethylamino) stilben Z & E 4'-yl} dimesityl borane (BNS) were synthesised and investigated for their non-linear optical properties. The results show that the quadratic hyperpolarisability of the Z-isomer is smaller than that of the E-isomer, the beta value found for the latter being as high as 60 × 10?30 esu. 相似文献
3.
Non-contact handling in microassembly: Acoustical levitation 总被引:1,自引:0,他引:1
Microassembly is currently of the utmost importance in industry. Nevertheless, the classical assembly processes are no longer usable for very small components, typically ranging from 10 m to 10 mm, since usually neglected surface forces disturb the handling task by inducing adhesion between the component and the gripper. A promising alternative to tackle surface forces consists in levitating the handled component. The various advantages of this contactless handling method are reviewed here and justify the choice of this approach. Consequently, the numerous physical principles suitable for contactless handling are briefly described together with their limitations. The evaluation shows that acoustic levitation is best fitted in the case of microassembly. A classification of literature applications is presented hereafter with special focus on acoustic levitation. Finally, the most common models of acoustical levitation are inspected in a general way. The described models come within the scope of non-linear acoustics. 相似文献
4.
Accurate quantitative determinations are often difficult to obtain from fluorescence analysis of complex samples due to sample matrix effects and intermolecular interactions between solutes. Organized media can be used to minimize these unwanted processes without physical separation or extraction of the analytes from the sample matrix by isolating the analyte molecules in a uniform microenvironment within the sample. The advantages of bile salt micellar media over conventional detergent micelles are demonstrated for analysis of coal liquids. The bile salt media is shown to increase the sensitivity and dynamic range of fluorescence measurements relative to simple ethanolic solutions, without promoting gound-state and excited-state interactions that occur in the detergent micellar media. 相似文献
5.
Discusses problems involved in collecting data based on observation of small groups. The example of a study of manifestations of cooperation in groups of preschoolers (aged 21–57 mo) is used for illustration. Statistical treatment of observation data and global analysis of data are considered. (English abstract) (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
6.
Simple bounds on the extreme eigenvalues of Toeplitz matrices 总被引:1,自引:0,他引:1
Hertz D. 《IEEE transactions on information theory / Professional Technical Group on Information Theory》1992,38(1):175-176
Simple bounds are presented on the extreme eigenvalues of n ×n -dimensional Hermitian Toeplitz matrices. Such a matrix, say T n, is determined by its first row. The proposed bounds have low complexity O (n ); furthermore, examples are presented for which the proposed bounds are tighter than the Slepian-Landau bounds at their best, i.e. when the extreme eigenvalues of the submatrix obtained by deleting the first row and first column of T n are known exactly. The bounds are first presented on the extreme eigenvalues of Hermitian Toeplitz matrices: the corresponding bounds for real symmetric Toeplitz matrices follow as a special case. Then, these bounds are extended to Hermitian Toeplitz interval matrices 相似文献
7.
Frdric Ampe Alain Brauman Serge Treche Aurelien Agossou 《Journal of the science of food and agriculture》1994,65(3):355-361
Retting, a spontaneous and traditional fermentation of cassava roots in Central Africa, was optimised in terms of time and the quality of the end-product. Optimal conditions were achieved by using an experimental research methodology. Temperature is the most influential factor, with an optimum of 34°C for quicker retting. The roots should be peeled and soaked in water immediately after harvesting to increase the quality of cassava foods. Inoculation of water with juice from a prior retting helps in cassava detoxification but has no influence on the time or the quality of foo-foo. Foo-foo samples had the most favourable organoleptic quality when an incubation temperature of between 28 and 37°C was used. Using optimal conditions, retting time was reduced 3-fold, and foo-foo of high and constant quality could be processed. 相似文献
8.
9.
The ring-opening polymerization of hexamethylcyclodisilazane (D2NMe), initiated by methyl triflate in 1,2-dichloroethane, forms in the first, fast kinetic step both linear polymer and cyclic dimer (D4NMe). Subsequently a slow depolymerization process occurs leading to exclusively cyclotrisilazane (D3NMe). On the basis of kinetic measurements carried out using an adiabatic calorimetric technique and complementary experiments, mechanisms of both propagation, cyclization and back-biting reactions are proposed. The influence of the reaction temperature was also studied; it is demonstrated that, at low temperature, polymerization does not lead to cyclic oligomer formation. In such conditions, the polymerization presents a ‘living’ character. 相似文献
10.
Thermoforming (free blowing) of poly(ethylene terephthalate) preforms was successfully and quickly performed in a rotating system designed for dielectric hysteresis heating. Temperature profile modeling was carried out with the amorphous poly(ethylene terephthalate) permittivity at different temperatures. The Maxwell and heat equations were used to determine the best profile and power tuning. The determination of the theoretical boundary conditions was accomplished by the adjustment of the numerical transient external surface wall temperature with experimental infrared pyrometry results. In comparison with infrared, microwaves allowed high power density absorption inside the perform wall without a dramatic temperature gradient. Consequently, the heat blowing stage could be accelerated, and the process took at least 5 times less energy than infrared heating. Industrial applications involve the integration of the molding step and the design of the overall process. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008 相似文献