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In this paper we present a modeling approach suitable for practical evaluation of the delays that may affect security monitoring systems in (multitenant) cloud based architecture, and in general to support professionals in planning and evaluating relevant parameters in dealing with new designs or migration projects. The approach is based on modularity and multiformalism techniques to manage complexity and guide designers in an incremental process, to help transferring technical knowledge into modeling practice and to help easing the use of simulation. We present a case study based on a real experience, triggered by a new legal requirement that Italian Public Administration should comply about their datacenters.

Cloud based architectures present many challenges, ranging from poorly dimensioned hardware to lengthy wait times and resource balancing issues. Most of these problems can be mitigated by using proper performance evaluation techniques, depending on the accuracy of the model abstracting the real system. The adoption of a formalism over another to describe the considered infrastructure plays a crucial role in achieving this goal. In this sense, multiformalism proves itself to be a powerful modeling approach describing each system component according to the most suitable representation. This paper presents a novel modeling method oriented to the prediction of cloud architectures performance, suitable for joining the advantages of high level modeling abstractions and of the detail of a specialized simulator. Generalized Stochastic Petri Nets are used to describe the workload and the behavior of users and applications, while Cloudsim, a well known cloud infrastructure simulator, is adopted for the cloud part. A case study of a simplified Edge Computing application is presented to demonstrate the effectiveness of the proposed approach.

Wharton’s jelly (WJ), the main constituent of umbilical cord, is a reliable source of mesenchymal stem cells (MSC). WJ-MSC show unique ability in crossing lineage borders. As other extraembryonic mesenchymal populations (placenta and amnionderived cells), WJ-MSC express several immunomodulatory molecules, essential during the initial phases of human development. Indeed, our recent work pointed out the expression of non-classical HLA molecules as HLA-G in such cells, together with a favorable combination of B7 costimulators. Very few data in literature suggest that some of the immune features of the naïve cells are maintained after performing differentiation. The aim of this work was extending the knowledge on the expression of immunomodulatory molecules by naïve and differentiated WJ-MSC. To this purpose, WJMSC underwent differentiation to osteoblasts, adipocytes and hepatocyte-like cells. Differentiated cells were characterized, by both RT-PCR, ICC and histological stains for the acquisistion of the desired phenotypical features. RT-PCR and ICC were used to investigate the differential expression of immune-related molecules in control and differentiated cells. WJ-MSC resulted expressing diverse immunomodulatory molecules which spans from non-classical type I HLAs (i.e. HLA-E, -F, -G) , to further members of the B7 family, and of the CEA superfamily, for all of which in vivo immunomodulating functions are known. In addition, we demonstrated for the first time that the expression of these molecules is maintained after performing osteogenic, adipogenic or hepatogenic differentiation. Further experiments are undergoing to better evaluating the implications of these findings in the evolving field of liver regenerative medicine.