@proceedings {250, title = {Workload-Based Software Rejuvenation in Cloud Systems}, journal = {IEEE TRANSACTIONS ON COMPUTERS}, volume = {62}, year = {2013}, pages = {1072{\textendash}1085}, abstract = {

Cloud Computing is a promising paradigm able to rationalize the use of hardware resources by means of virtualization. Virtualization allows to instantiate one or more virtual machines (VMs) on top of a single physical machine managed by a virtual machine monitor (VMM). Similarly to any other software, a VMM experiences aging and failures. Software rejuvenation is a proactive fault management technique that involves terminating an application, cleaning up the system internal state, and restarting it in order to prevent the occurrence of future failures. In this work, we propose a technique to model and evaluate the VMM aging process and to investigate the optimal rejuvenation policy that maximizes the VMM availability under variable workload conditions. Starting from dynamic reliability theory and adopting symbolic algebraic techniques, we investigate and compare existing time-based VMM rejuvenation policies. We also propose a time-based policy that adapts the rejuvenation timer to the VMM workload condition improving the system availability. The effectiveness of the proposed modeling technique is demonstrated through a numerical example based on a case study taken from the literature.

}, keywords = {cloud computing, Dynamic Availability, Kronecker algebra, phase type distributions, Time-based Rejuvenation}, doi = {10.1109/TC.2013.30}, author = {Bruneo D. and Distefano S. and Longo F. and Puliafito A and Scarpa M} } @booklet {253, title = {Energy Management in Industrial Plants}, journal = {COMPUTERS}, volume = {1}, year = {2012}, pages = {24{\textendash}40}, abstract = {The Smart Grid vision imposes a new approach towards energy supply that is more affordable, reliable and sustainable. The core of this new vision is the use of advanced technology to monitor power system dynamics in real time and identify system in stability. In order to implement strategic vision for energy management, it is possible to identify three main areas of investigation such as smart generation, smart grid and smart customer. Focusing on the latter topic, in this paper we present an application specifically designed to monitor an industrial site with particular attention to power consumption. This solution is a real time analysis tool, able to produce useful results to have a strategic approach in the energy market and to provide statistic analysis useful for the future choices of the industrial company. The application is based on a three layers architecture. The technological layer uses a Wireless Sensor Network (WSN) to acquire data from the electrical substations. The middleware layer faces the integration problems by processing the raw data. The application layer manages the data acquired from the sensors. This WSN based architecture represents an interesting example of a low cost and non-invasive monitoring application to keep the energy consumption of an industrial site under control. Some of the added value features of the proposed solution are the routing network protocol, selected in order to have an high availability of the WSN, and the use of the WhereX middleware, able to easily implement integration among the different architectural parts.}, keywords = {middleware, monitoring tool, routing protocols, sensor networks}, doi = {10.3390/computers1010024}, author = {Bruneo D and Cucinotta A and Longo A and Puliafito A and Scarpa M} } @booklet {303, title = {Modeling Distributed Computing System Reliability with DRBD}, journal = {Reliable Distributed Systems, 2006. SRDS {\textquoteright}06. 25th IEEE Symposium on}, year = {2006}, month = {4, 2006}, pages = {106{\textendash}118}, publisher = {IEEE}, address = {Piscataway, NJ}, author = {Distefano S and Scarpa M and Puliafito A} } @booklet {302, title = {A modeling technique for the performance analysis of Web searching applications}, journal = {IEEE TRANSACTIONS ON KNOWLEDGE AND DATA ENGINEERING}, volume = {16}, year = {2004}, pages = {1339{\textendash}1356}, abstract = {This paper proposes a methodological approach for the performance analysis of Web-based searching applications on the Internet. It specifically investigates the behavior of the Client/Server (C/S), Remote-Evaluation (REV) and Mobile-Agent (MA) communication paradigms and describes how Petri-net models can be developed to derive performance indices which can help the designer to improve the efficiency of his distributed applications. Our purpose is that of identifying a set of models that can help to understand the environmental situations in which such paradigms should be preferred or combined in order to optimize the performances of a distributed system. In particular, we propose a modeling technique applied to an Information Retrieval application on the World Wide Web. An analytical evaluation through the solution of non-Markovian Petri-net models is provided, which allows us to identify the main parameters, as well as the way they interact, to be taken into consideration when distributed applications are to be designed. An experimental environment is also studied in order to obtain real measurements used to validate the analytical models.}, keywords = {Communication paradigms, Distributed data bases, Mobile agents, Petri-nets modeling}, author = {Scarpa M and Puliafito A and Villari M. and ZAIA A} } @booklet {301, title = {UML Design and Software Performance Modeling}, journal = {Computer and Information Sciences - ISCIS 2004}, volume = {3280}, year = {2004}, month = {29 OTTOBRE 2004}, pages = {564{\textendash}573}, publisher = {Springer}, address = {Heidelberg}, doi = {10.1007/b101749}, author = {Distefano S. and PACI D and Puliafito A and Scarpa M} } @booklet {311, title = {Which paradigm should I use? An analytical comparison of the client-server, remote evaluation and mobile agent paradigms}, journal = {CONCURRENCY AND COMPUTATION}, volume = {13}, year = {2001}, pages = {71{\textendash}94}, author = {Puliafito A. and RICCOBENE S and Scarpa M} }