Parallel distributed algorithms of the beta-model of the small world graphs

The research goal is to develop a large-scale agent-based simulation environment to support implementations of Internet simulation applications.The Small Worlds (SW) graphs are used to model Web sites and social networks of Internet users. Each vertex represents the identity of a simple agent. In order to cope with scalability issues, we have to consider distributed parallel processing. The focus of this paper is to present two parallel-distributed algorithms for the construction of a particular type of SW graph called Beta-model. The first algorithm serializes the graph construction, while the second constructs the graph in parallel

Fluorescent Markers in Water Treatment

Both phosphonate- and polymer-based scale inhibitors have a broad spectrum of applications in water treatment technologies. However, the “online” monitoring of antiscalant content in an aqueous phase is still a challenge for researchers. A possible solution is provided by the fluorescent markers added to the feeding water. These can be either an antiscalant tagged or may represent the independent species. The review summarizes both the advantages and the drawbacks of these approaches along with such markers’ classification, with a special emphasis on the novel fluorescent-tagged phosphonates. Besides, some unique opportunities provided by the fluorescent-tagged antiscalants for reverse osmosis membrane mapping, scale inhibition traceability, and a scale inhibitor localization in a circulation water facility are also considered and discussed

Achieving Robust Self-Management for Large-Scale Distributed Applications

Autonomic managers are the main architectural building blocks for constructing self-management capabilities of computing systems and applications. One of the major challenges in developing self-managing applications is robustness of management elements which form autonomic managers. We believe that transparent handling of the effects of resource churn (joins/leaves/failures) on management should be an essential feature of a platform for self-managing large-scale dynamic distributed applications, because it facilitates the development of robust autonomic managers and hence improves robustness of self-managing applications. This feature can be achieved by providing a robust management element abstraction that hides churn from the programmer. In this paper, we present a generic approach to achieve robust services that is based on finite state machine replication with dynamic reconfiguration of replica sets. We contribute a decentralized algorithm that maintains the set of nodes hosting service replicas in the presence of churn. We use this approach to implement robust management elements as robust services that can operate despite of churn. Our proposed decentralized algorithm uses peer-to-peer replica placement schemes to automate replicated state machine migration in order to tolerate churn. Our algorithm exploits lookup and failure detection facilities of a structured overlay network for managing the set of active replicas. Using the proposed approach, we can achieve a long running and highly available service, without human intervention, in the presence of resource churn. In order to validate and evaluate our approach, we have implemented a prototype that includes the proposed algorithm

Професор Стефана Димитрова – забележителен учен и човек

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Comment on ``Exact three-dimensional wave function and the on-shell t matrix for the sharply cut-off Coulomb potential: Failure of the standard renormalization factor''

The solutions analytically derived by Gloeckle et al. [Phys. Rev. C79, 044003 (2009)] for the three-dimensional wave function and on-shell t matrix in the case of scattering on a sharply cut-off Coulomb potential appear to be fallacious. And their renormalization factor lacks mathematical grounds.Comment: 5 page

Formation of Disperse Silver Deposits by the Electrodeposition Processes at High Overpotentials

In this study, electrodeposition of silver from nitrate solution at the high overpotentials was analyzed. Morphologies of silver deposits obtained at the different overpotentials and with the different electrodeposition times were examined using the technique of scanning electron microscopy (SEM). The different disperse morphological forms, such as granules, needle-like and spongy-dendritic ones were formed during silver electrodeposition from this solution. The size of granules decreased and their number increased with the increase of overpotential of electrodeposition. With the increasing overpotential, the induction time for the appearance of spongy-dendritic forms decreased with a tendency to increase their ramification. Mathematic model describing the mechanism of metal electrodeposition at the high overpotentials is proposed and discussed on the basis of the obtained silver surface morphology