HYBRID CLOUD EXPLOITING THE ASSETS OF BUSINESS VALUE

Cloud is kind of centralized database where numerous clients accumulate their data, recover data and possibly adjust data and it is a representation where user is made available services by Cloud Service Provider on the basis of pay per use.  Numerous organizations are now taking most important steps in the direction of cloud computing. A hybrid cloud is a grouping of both public and private clouds which are bound mutually by either harmonized or proprietary knowledge that facilitates data and application portability. Hybrid clouds present the benefits of outlay and scale of public clouds although also offering the security and organizing of private clouds. Hybrid clouds can be measured an intermediary stage as enterprises organize to progress for the most part of their workloads to public clouds. All along with the characteristic security concerns associated through private clouds, there are several additional factors one should regard in a hybrid environment. Hybrid environments entail both on-premise and public cloud providers, several additional infrastructure security considerations come into the view which is normally related with public clouds

Galactic fountains and their connection with high and intermediate velocity clouds

The aim of this paper is to calculate the expansion law and chemical enrichment of a supershell powered by the energetic feedback of a typical Galactic OB association at various galactocentric radii. We study then the orbits of the fragments created when the supershell breaks out and we compare their kinetic and chemical properties with the available observations of high - and intermediate - velocity clouds. We use the Kompaneets (1960) approximation for the evolution of the superbubble driven by sequential supernova explosions and we compute the abundances of oxygen and iron residing in the thin cold supershell. We assume that supershells are fragmented by means of Rayleigh-Taylor instabilities and we follow the orbit of the clouds either ballistically or by means of a hybrid model considering viscous interaction between the clouds and the extra-planar gas.Given the self-similarity of the Kompaneets solutions, clouds are always formed ~ 448 pc above the plane. If the initial metallicity is solar, the pollution from dying stars of the OB association has a negligible effect on the chemical composition of the clouds. The maximum height reached by the clouds above the plane seldom exceeds 2 kpc and when averaging over different throwing angles, the landing coordinate differs from the throwing coordinate ~ 1 kpc at most. The range of heights and [O/Fe] ratios spun by our clouds suggest us that the high velocity clouds cannot have a Galactic origin, whereas intermediate velocity clouds have kinematic properties similar to our modeled clouds but overabundance observed for the [O/Fe] ratios which can be reproduced only with initial metallicities which are too low compared for those of the Galaxy disk.Comment: Accepted 17/03/2008 by A&

Efficient production of an 87Rb F = 2, mF = 2 Bose-Einstein condensate in a hybrid trap

We have realized Bose-Einstein condensation (BEC) of 87Rb in the F=2, m_F=2 hyperfine substate in a hybrid trap, consisting of a quadrupole magnetic field and a single optical dipole beam. The symmetry axis of the quadrupole magnetic trap coincides with the optical beam axis, which gives stronger axial confinement than previous hybrid traps. After loading 2x10^6 atoms at 14 muK from a quadrupole magnetic trap into the hybrid trap, we perform efficient forced evaporation and reach the onset of BEC at a temperature of 0.5 muK and with 4x10^5 atoms. We also obtain thermal clouds of 1x10^6 atoms below 1 muK in a pure single beam optical dipole trap, by ramping down the magnetic field gradient after evaporative cooling in the hybrid trap.Comment: 8 pages, 8 figures, improved on basis of referee comment

Challenge Token Based Security for Hybrid Clouds

Cloud has now become the essential part of the web technology and fast growth of cloud computing technique making it worth for the companies to invest in cloud. Growth of number of clouds is requiring inter cloud communication as concept of multi cloud or hybrid cloud is also spreading quickly. With this fast growth, more and more challenges are arising in the field of cloud computing. Various researchers are focusing on cloud oriented challenges and lots of research works are going on in this field. With emergence of cloud computing, the term "Hybrid Topology" or "Hybrid Deployment" is becoming more and more common. A "Hybrid Cloud" is group of clouds you join different cloud deployments into one connected cluster. Another area of research is to focus on communication between a cloud and non cloud computing system. Hybrid Cloud computing mainly deals with working of data centers where different software are installed with huge of growing data to provide information to the users of the system. The techniques which can be used in hybrid cloud securities can be built around the encryption and decryption of data, key based security algorithms which are mainly oriented on authentication and authorization techniques as in wired and wireless networks. One such mechanism is to share the challenge text between the clouds before actual communication should start for authentication. The various works done in this area till date are oriented on other techniques of security between the two or more clouds in a hybrid cloud

Implementation and Provisioning of Federated Networks in Hybrid Clouds (pre-print)

Federated cloud networking is needed to allow the seamless and efficient interconnection of resources distributed among different clouds. This work introduces a new cloud network federation framework for the automatic provision of Layer 2 (L2) and layer 3 (L3) virtual networks to interconnect geographically distributed cloud infrastructures in a hybrid cloud scenario. After a revision of existing encapsulation technologies to implement L2 and L3 overlay networks, the paper analyzes the main topologies that can be used to construct federated network overlays within hybrid clouds. In order to demonstrate the proposed solution and compare the different topologies, the article shows a proof-of-concept of a real federated network deployment in a hybrid cloud, which spans a local private cloud, managed with OpenNebula, and two public clouds, two different regions of mazon EC2. Results show that L2 and L3 overlay connectivity can be achieved with a minimal bandwidth overhead, lower than 10%

Resource allocation and scheduling of multiple composite web services in cloud computing using cooperative coevolution genetic algorithm

In cloud computing, resource allocation and scheduling of multiple composite web services is an important and challenging problem. This is especially so in a hybrid cloud where there may be some low-cost resources available from private clouds and some high-cost resources from public clouds. Meeting this challenge involves two classical computational problems: one is assigning resources to each of the tasks in the composite web services; the other is scheduling the allocated resources when each resource may be used by multiple tasks at different points of time. In addition, Quality-of-Service (QoS) issues, such as execution time and running costs, must be considered in the resource allocation and scheduling problem. Here we present a Cooperative Coevolutionary Genetic Algorithm (CCGA) to solve the deadline-constrained resource allocation and scheduling problem for multiple composite web services. Experimental results show that our CCGA is both efficient and scalable

The ARCiS framework for Exoplanet Atmospheres: The Cloud Transport Model

Understanding of clouds is instrumental in interpreting current and future spectroscopic observations of exoplanets. Modelling clouds consistently is complex, since it involves many facets of chemistry, nucleation theory, condensation physics, coagulation, and particle transport. We develop a simple physical model for cloud formation and transport, efficient and versatile enough that it can be used in modular fashion for parameter optimization searches of exoplanet atmosphere spectra. The transport equations are formulated in 1D, accounting for sedimentation and diffusion. The grain size is obtained through a moment method. For simplicity, only one cloud species is considered and the nucleation rate is parametrized. From the resulting physical profiles we simulate transmission spectra covering the visual to mid-IR wavelength range. We apply our models towards KCl clouds in the atmosphere of GJ1214 b and towards MgSiO3 clouds of a canonical hot-Jupiter. We find that larger cloud diffusivity $K_{zz}$ increases the thickness of the cloud, pushing the $\tau=1$ surface to a lower pressure layer higher in the atmosphere. A larger nucleation rate also increases the cloud thickness while it suppresses the grain size. Coagulation is most important at high nuclei injection rates ($\dot\Sigma_n$) and low $K_{zz}$. We find that the investigated combinations of $K_{zz}$ and $\dot\Sigma_n$ greatly affect the transmission spectra in terms of the slope at near-IR wavelength (a proxy for grain size), the molecular features seen at ~1\micr (which disappear for thick clouds, high in the atmosphere), and the 10\micr silicate feature, which becomes prominent for small grains high in the atmosphere. The result of our hybrid approach -- aimed to provide a good balance between physical consistency and computational efficiency -- is ideal towards interpreting (future) spectroscopic observations of exoplanets.Comment: language and other tiny correction