Publications

Authors: Andreas Tsagkaropoulos, Yiannis Verginadis , Maxime Compastié, Dimitris Apostolou and Gregoris Mentzas

Source: https://www.mdpi.com/2079-9292/10/6/737

Abstract: The emergence of fog and edge computing has complemented cloud computing in the design of pervasive, computing-intensive applications. The proximity of fog resources to data sources has contributed to minimizing network operating expenditure and has permitted latency-aware processing. Furthermore, novel approaches such as serverless computing change the structure of applications and challenge the monopoly of traditional Virtual Machine (VM)-based applications. However, the efforts directed to the modeling of cloud applications have not yet evolved to exploit these breakthroughs and handle the whole application lifecycle efficiently. In this work, we present a set of Topology and Orchestration Specification for Cloud Applications (TOSCA) extensions to model applications relying on any combination of the aforementioned technologies. Our approach features a design-time “type-level” flavor and a run time “instance-level” flavor. The introduction of semantic enhancements and the use of two TOSCA flavors enables the optimization of a candidate topology before its deployment. The optimization modeling is achieved using a set of constraints, requirements, and criteria independent from the underlying hosting infrastructure (i.e., clouds, multi-clouds, edge devices). Furthermore, we discuss the advantages of such an approach in comparison to other notable cloud application deployment approaches and provide directions for future research.

Authors: Elisabeth Roggenhofer, Sandrine Muller, Emiliano Santarnecchi, Lester Melie-Garcia, Roland Wiest, Ferath Kherif, Bogdan Draganski

Source: https://www.mdpi.com/2079-9292/10/6/737

Abstract: Mesial temporal lobe epilepsy (TLE) is one of the most widespread neurological network disorders. Computational anatomy MRI studies demonstrate a robust pattern of cortical volume loss. Most statistical analyses provide information about localization of significant focal differences in a segregationist way. Multivariate Bayesian modeling provides a framework allowing inferences about inter-regional dependencies. We adopt this approach to answer following questions: Which structures within a pattern of dynamic epilepsy-associated brain anatomy reorganization best predict TLE pathology. Do these structures differ between TLE subtypes?

Authors: Alberto Redolfi1, Silvia De Francesco, Fulvia Palesi, Samantha Galluzzi, Cristina Muscio, Gloria Castellazzi, Pietro Tiraboschi, Giovanni Savini, Anna Nigri, Gabriella Bottini, Maria Grazia Bruzzone, Matteo Cotta Ramusino, Stefania Ferraro, Claudia A. M. Gandini Wheeler-Kingshott, Fabrizio Tagliavini5, Giovanni B. Frisoni, Philippe Ryvlin, Jean-François Demonet, Ferath Kherif, Stefano F. Cappa and Egidio D’Angelo

Source: https://www.mdpi.com/2079-9292/10/6/737

Abstract: With the shift of research focus to personalized medicine in Alzheimer’s Dementia (AD), there is an urgent need for tools that are capable of quantifying a patient’s risk using diagnostic biomarkers. The Medical Informatics Platform (MIP) is a distributed e-infrastructure federating large amounts of data coupled with machine-learning (ML) algorithms and statistical models to define the biological signature of the disease. The present study assessed (i) the accuracy of two ML algorithms, i.e., supervised Gradient Boosting (GB) and semi-unsupervised 3C strategy (Categorize, Cluster, Classify—CCC) implemented in the MIP and (ii) their contribution over the standard diagnostic workup.

Authors: Gretel Sanabria-Diaz, Lester Melie-Garcia, Bogdan Draganski, Jean-Francois Demonet & Ferath Kherif

Source: https://www.mdpi.com/2079-9292/10/6/737

Abstract: The Apolipoprotein E isoform E4 (ApoE4) is consistently associated with an elevated risk of developing late-onset Alzheimer’s Disease (AD); however, less is known about the potential genetic modulation of the brain networks organization during prodromal stages like Mild Cognitive Impairment (MCI). To investigate this issue during this critical stage, we used a dataset with a cross-sectional sample of 253 MCI patients divided into ApoE4-positive (‛Carriers’) and ApoE4-negative (‘non-Carriers’). We estimated the cortical thickness (CT) from high-resolution T1-weighted structural magnetic images to calculate the correlation among anatomical regions across subjects and build the CT covariance networks (CT-Nets). The topological properties of CT-Nets were described through the graph theory approach. Specifically, our results showed a significant decrease in characteristic path length, clustering-index, local efficiency, global connectivity, modularity, and increased global efficiency for Carriers compared to non-Carriers. Overall, we found that ApoE4 in MCI shaped the topological organization of CT-Nets. Our results suggest that in the MCI stage, the ApoE4 disrupting the CT correlation between regions may be due to adaptive mechanisms to sustain the information transmission across distant brain regions to maintain the cognitive and behavioral abilities before the occurrence of the most severe symptoms.

Authors: Ladina Weitnauera, Stefan Frischbde, Lester Melie-Garciaa, Martin Preisigf, Matthias L.SchroeterbInes, Sajfutdinowc , Ferath Kherifa, Bogdan Draganskiab

Source: https://www.mdpi.com/2079-9292/10/6/737

Abstract: There is ongoing debate about the role of cortical and subcortical brain areas in force modulation. In a whole-brain approach, we sought to investigate the anatomical basis of grip force whilst acknowledging interindividual differences in connectivity patterns. We tested if brain lesion mapping in patients with unilateral motor deficits can inform whole-brain structural connectivity analysis in healthy controls to uncover the networks underlying grip force.

Authors: Andreas Tsagkaropoulos, Yiannis Verginadis, Nikos Papageorgiou, Fotis Paraskevopoulos, Dimitris Apostolou & Gregoris Mentzas

Source: https://www.mdpi.com/2079-9292/10/6/737

Abstract: While a multitude of cloud vendors exist today offering flexible application hosting services, the application adaptation capabilities provided in terms of autoscaling are rather limited. In most cases, a static adaptation action is used having a fixed scaling response. In the cases that a dynamic adaptation action is provided, this is based on a single scaling variable. We propose Severity, a novel algorithmic approach aiding the adaptation of cloud applications. Based on the input of the DevOps, our approach detects situations, calculates their Severity and proposes adaptations which can lead to better application performance. Severity can be calculated for any number of application QoS attributes and any type of such attributes, whether bounded or unbounded. Evaluation with four distinct workload types and a variety of monitoring attributes shows that QoS for particular application categories is improved. The feasibility of our approach is demonstrated with a prototype implementation of an application adaptation manager, for which the source code is provided.

Authors: Yiannis Verginadis, Kyriakos Kritikos, Ioannis Patiniotakis

Source: https://www.mdpi.com/2079-9292/10/6/737

Abstract: Multi-cloud management prevents vendor lock-in as well as improves the provisioning of cloud applications. However, the optimal deployment of such applications is still impossible, not only due to the dynamicity of the cloud and hybrid environments that host these applications but also due to the use of potentially unsuitable forms or configurations of application components. As such, the real cloud application optimisation can only be achieved by considering all possible component forms and selecting the best one, based on both application requirements and the current context. This gives rise to the era of polymorphic applications which can change form at runtime based on their context. A major pre-requisite for the management of such applications is their proper modelling. Therefore, this paper presents extensions on two well-integrated cloud modelling solutions to support the complete specification of polymorphic applications and it presents an illustrative example of their use.

Authors: Jean-Didier Totow Tom-Ata and Dimosthenis Kyriazis

Source: https://www.mdpi.com/2079-9292/10/6/737

Abstract: Applications performance is strongly linked with the total load, the application deployment architecture and the amount of resources allocated by the cloud or edge computing environments. Considering that the majority of the applications tends to be data intensive, the load becomes quite dynamic and depends on the data aspects, such as the data sources locations, their distribution and the data processing aspects within an application that consists of micro-services. In this paper we introduce an analysis and prediction model that takes into account the characteristics of an application in terms of data aspects and the edge computing resources attributes, such as utilization and concurrency, in order to propose optimized resources allocation during runtime.

Authors: Alessandra Bagnato, Etienne Brosse and Kaïs Chaabouni

Source: https://www.mdpi.com/2079-9292/10/6/737

Abstract: The Morphemic H2020 project covers several features from modelling cross-cloud applications, continuous and autonomous optimization and deployment and providing access to several cloud capabilities. This demo paper describes the MORPHEMIC CAMEL Designer tool responsible of the Cloud Application Modelling and Execution Language (CAMEL) design for the modelling Environment Modelio. CAMEL Designer is an open source module for graphically creating, editing and exporting CAMEL Models in XMI format.