Smart CloudBench—A framework for evaluating cloud infrastructure performance

Cloud migration allows organizations to benefit from reduced operational costs, improved flexibility, and greater scalability, and enables them to focus on core business goals. However, it also has the flip side of reduced visibility. Enterprises considering migration of their IT systems to the cloud only have a black box view of the offered infrastructure. While information about server pricing and specification is publicly available, there is limited information about cloud infrastructure performance. Comparison of alternative cloud infrastructure offerings based only on price and server specification is difficult because cloud vendors use heterogeneous hardware resources, offer different server configurations, apply different pricing models and use different virtualization techniques to provision them. Benchmarking the performance of software systems deployed on the top of the black box cloud infrastructure offers one way to evaluate the performance of available cloud server alternatives. However, this process can be complex, time-consuming and expensive, and cloud consumers can greatly benefit from tools that can automate it. Smart CloudBench is a generic framework and system that offers automated, on-demand, real-time and customized benchmarking of software systems deployed on cloud infrastructure. It provides greater visibility and insight into the run-time behavior of cloud infrastructure, helping consumers to compare and contrast available offerings during the initial cloud selection phase, and monitor performance for service quality assurance during the subsequent cloud consumption phase. In this paper, we first discuss the rationale behind our approach for benchmarking the black box cloud infrastructure. Then, we propose a generic architecture for benchmarking representative applications on the heterogeneous cloud infrastructure and describe the Smart CloudBench benchmarking workflow. We also present simple use case scenarios that highlight the need for tools such as Smart CloudBench.     

AGENT ENABLED ADAPTIVE MANAGEMENT OF QoS ASSURED PROVISION OF COMPOSITE SERVICES

The assurance of quality-of-service (QoS) is critical for the successful deployment of service-oriented applications, especially in open, dynamic, and distributed cross-organizational environments. Adaptive management of the QoS assured provision of composite services is required for more reliable, fault-tolerant, and flexible service delivery in such environments. It can be realized with software agents offering a unified framework and necessary capabilities for carrying out different adaptive management tasks across the whole lifecycle of composite service provision.     

Robust Surface Fitting from Two Views using Restricted Correspondence

The restricted correspondence problem is the task of solving the classical stereo correspondence problem when the surface being observed is known to belong to a family of surfaces that vary in a known way with one or more parameters. Under this constraint the surface can be extracted far more robustly than by classical stereo applied to an arbitrary surface, since the problem is solved semi-globally, rather than locally for each epipolar line. Here, the restricted correspondence problem is solved for two examples, the first being the extraction of the parameters of an ellipsoid from a calibrated stereo pair. The second example is the estimation of the osculating paraboloid at the frontier points of a convex object.

Estimation of constant thermal conductivity by use of Proper Orthogonal Decomposition

An inverse approach is developed to estimate the unknown heat conductivity and the convective heat transfer coefficient. The method relies on proper orthogonal decomposition (POD) in order to filter out the higher frequency error. The idea is to solve a sequence of direct problems within the body under consideration. The solution of each problem is sampled at a predefined set of points. Each sampled temperature field, known in POD parlance as a snapshot, is obtained for an assumed value of the retrieved parameters. POD analysis, as an efficient mean of detecting correlation between the snapshots, yields a small set of orthogonal vectors (POD basis), constituting an optimal set of approximation functions. The temperature field is then expressed as a linear combination of the POD vectors. In standard applications, the coefficients of this combination are assumed to be constant. In the proposed approach, the coefficients are allowed to be a nonlinear function of the retrieved parameters. The result is a trained POD base, which is then used in inverse analysis, resorting to a condition of minimization of the discrepancy between the measured temperatures and values calculated from the model. Several numerical examples show the robustness and numerical stability of the scheme.     

Planar Silicene: A New Silicon Allotrope Epitaxially Grown by Segregation

2D sheets of graphene‐like silicon, namely planar silicene, are synthesized. This new silicon allotrope is prepared on Au(111) thin films grown on a Si(111) substrate in the process of surface segregation. Owing to its almost perfectly flat geometry it shares the atomic structure with graphene rather than with low‐buckled silicene. Scanning tunneling microscopy measurements clearly display an atomically resolved planar silicene honeycomb lattice. Ab initio density functional theory calculations fully support the experimental findings and predict a pure sp² atomic configuration of Si atoms. The present work is the first experimental evidence of epitaxial planar silicene.     

Antioxidant activity of protein hydrolyzates from aquatic species

Antioxidant activity of protein hydrolyzates from capelin (Mallotus villosus) and harp seal (Phoca groenlandica) was examined in a β-carotene/linoleate model system. Capelin protein hydrolyzates exhibited a significant (P<0.05) antioxidant effect during the entire or a portion of the 120-min incubation period when added to model systems at 1 to 10-mg levels per 5 mL of lipid emulsion. However, systems containing 10 mg of seal protein hydrolyzate (SPH) displayed a singificant (P<0.05) prooxidative effect during the experimentation period, but the effect was less pronounced at 5 mg of SPH addition. This effect was reversed to a weak, but significant (P<0.05), antioxidant effect when 1 or 2 mg of SPH were present after 45, 105–120, and 30–120 min of incubation. Two-dimensional thinlayer chromatographic separation of both hydrolyzates gave spots with antioxidant and prooxidant activites.     

Influence of nitrogen on the degradation of toluene in a compost‐based biofilter

Two identical laboratory‐scale bioreactors were operated simultaneously, each treating an input air flow rate of 1 m³ h^?1. The biofilters consisted of multi‐stage columns, each stage packed with a compost‐based filtering material, which was not previously inoculated. The toluene inlet concentration was fixed at 1.5 g m^?3 of air. Apart from the necessary carbon, the elements nitrogen, phosphorus, sulfur, potassium and other micro‐elements are also essential for microbial metabolism. These were distributed throughout the filter bed material by periodic ‘irrigations’ with various test nutrient solutions. The performance of each biofilter was quantified by determining its toluene removal efficiency, and elimination capacity. Nutrient solution nitrogen levels were varied from 0 to 6.0 g dm^?3, which led to elimination capacities of up to 50 g m^?3 h^?1 being obtained for a toluene inlet load of 80 g m^?3 h^?1. A theoretical analysis also confirmed that the optimum nitrogen solution concentration lays in the range 4.0–6.0 g dm^?3. Validation of the irrigation mode was achieved by watering each biofilter stage individually. Vertical stage‐by‐stage stratification of the biofilter performance was not detected, ie each filter bed section removed the same amount of pollutant, the elimination capacity per stage being about 16 g m^?3 h^?1 per section of column. © 2001 Society of Chemical Industry     

Book Reviews

Books reviewed in this article:
Recent Developments in Spatial Analysis. Spatial Statistics, Behavioural Modelling, and Computational Intelligence. (Advances in Spatial Science) Manfred M. Fischer and Arthur Getis
Regional and Local Potential for Transformation in Poland. G. Gorzelak
The City and its Sciences. C.S. Bertuglia, G. Bianchi, A. Mela (Eds.)