articles by Marco Guazzone
Abstract We present the forensic analysis of the artifacts generated on Android smartphones by Ch... more Abstract We present the forensic analysis of the artifacts generated on Android smartphones by ChatSecure, a secure Instant Messaging application that provides strong encryption for transmitted and locally-stored data to ensure the privacy of its users. We show that ChatSecure stores local copies of both exchanged messages and files into two distinct, AES-256 encrypted databases, and we devise a technique able to decrypt them when the secret passphrase, chosen by the user as the initial step of the encryption process, is known. Furthermore, we show how this passphrase can be identified and extracted from the volatile memory of the device, where it persists for the entire execution of ChatSecure after having been entered by the user, thus allowing one to carry out decryption even if the passphrase is not revealed by the user. Finally, we discuss how to analyze and correlate the data stored in the databases used by ChatSecure to identify the \{IM\} accounts used by the user and his/her buddies to communicate, as well as to reconstruct the chronology and contents of the messages and files that have been exchanged among them. For our study we devise and use an experimental methodology, based on the use of emulated devices, that provides a very high degree of reproducibility of the results, and we validate the results it yields against those obtained from real smartphones.
Peer-to-Peer (P2P) Desktop Grids are computing infrastructures that aggregate a set of desktop-cl... more Peer-to-Peer (P2P) Desktop Grids are computing infrastructures that aggregate a set of desktop-class machines in which all the participating entities have the same roles, responsibilities, and rights. In this paper, we present ShareGrid, a P2P Desktop Grid infrastructure based on the OurGrid middleware, that federates the resources provided by a set of small research laboratories to easily share and use their computing resources. We discuss the techniques and tools we employed to ensure scalability, efficiency, and usability, and describe the various applications used on it. We also demonstrate the ability of ShareGrid of providing good performance and scalability by reporting the results of experimental evaluations carried out by running various applications with different resource requirements. Our experience with ShareGrid indicates that P2P Desktop Grids can represent an effective answer to the computing needs of small research laboratories, as long as they provide both ease of management and use, and good scalability and performance.
Modern cloud data centers rely on server consolidation (the allocation of several Virtual Machine... more Modern cloud data centers rely on server consolidation (the allocation of several Virtual Machines (VMs) on the same physical host) to minimize their costs. Choosing the right consolidation level (how many and which VMs are assigned to a physical server) is a challenging problem, since contemporary multi-tier cloud applications must meet Service Level Agreements (SLAs) in face of highly dynamic, non-stationary, and bursty workloads. In this paper, we deal with the problem of achieving the best consolidation level that can be attained without violating application SLAs. We tackle this problem by devising FC2Q, a resource management framework exploiting feedback fuzzy-logic control, that is able to dynamically adapt the physical CPU capacity allocated to the tiers of an application in order to precisely match the needs induced by the intensity of its current workload. We implement FC2Q on a real testbed, and use this implementation to demonstrate its ability of meeting the above goals by means of a thorough experimental evaluation, carried out with real-world cloud applications and workloads. Furthermore, we compare the performance achieved by FC2Q against those attained by existing state-of-the-art alternative solutions, and we show that FC2Q works better than them in all the considered experimental scenarios. . Prepared using cpeauth.cls [Version: 2010/05/13 v3.00] 2 C. ANGLANO ET AL.
Federations among sets of Cloud Providers (CPs), whereby a set of CPs agree to mutually use their... more Federations among sets of Cloud Providers (CPs), whereby a set of CPs agree to mutually use their own resources to run the VMs of other CPs, are considered a promising solution to the problem of reducing the energy cost. In this paper, we address the problem of federation formation for a set of CPs, whose solution is necessary to exploit the potential of cloud federations for the reduction of the energy bill. We devise an algorithm, based on cooperative game theory, that can be readily implemented in a distributed fashion, and that allows a set of CPs to cooperatively set up their federations in such a way that their individual profit is increased with respect to the case in which they work in isolation. We show that, by using our algorithm and the proposed CPs' utility function, they are able to self-organize into Nash-stable federations and, by means of iterated executions, to adapt themselves to environmental changes. Numerical results are presented to demonstrate the effectiveness of the proposed algorithm.
inproceedings by Marco Guazzone
ShareGrid is a peer-to-peer desktop grid aimed at satisfying the computing needs of the small res... more ShareGrid is a peer-to-peer desktop grid aimed at satisfying the computing needs of the small research laboratories located in the Piedmont area in Northern Italy. ShareGrid adopts a cooperative approach, in which each participant allows the other ones to use his/her own resources on a reciprocity basis. ShareGrid is based on the OurGrid middleware, that provides a set of mechanisms enabling participating entities to quickly, fairly, and securely share their resources. In this paper we report our experience in designing, deploying, and using ShareGrid, and we describe the applications using it, as well as the lessons we learned, the problems that still remain open, and some possible solutions to them.
Cloud computing is growing in popularity among computing paradigms for its appealing property of ... more Cloud computing is growing in popularity among computing paradigms for its appealing property of considering "Everything as a Service". The goal of a Cloud infrastructure provider is to maximize its profit by minimizing the amount of violations of Quality-of-Service (QoS) levels agreed with service providers, and, at the same time, by lowering infrastructure costs. Among these costs, the energy consumption induced by the Cloud infrastructure, for running Cloud services, plays a primary role. Unfortunately, the minimization of QoS violations and, at the same time, the reduction of energy consumption is a conflicting and challenging problem. In this paper, we propose a framework to automatically manage computing resources of Cloud infrastructures in order to simultaneously achieve suitable QoS levels and to reduce as much as possible the amount of energy used for providing services. We show, through simulation, that our approach is able to dynamically adapt to time-varying workloads (without any prior knowledge) and to significantly reduce QoS violations and energy consumption with respect to traditional static approaches.
Cloud computing is an emerging computing paradigm in which “Everything is as a Service”, includin... more Cloud computing is an emerging computing paradigm in which “Everything is as a Service”, including the provision of virtualized computing infrastructures (known as Infrastructure-as-a-Service modality) hosted on the physical infrastructure, owned by an infrastructure provider. The goal of this infrastructure provider is to maximize its profit by minimizing the amount of violations of Quality-of-Service (QoS) levels agreed with its customers and, at the same time, by lowering infrastructure costs among which energy consumption plays a major role. In this paper, we propose a framework able to automatically manage resources of cloud infrastructures in order to simultaneously achieve suitable QoS levels and to reduce as much as possible the amount of energy used for providing services. We show, through simulation, that our approach is able to dynamically adapt to time-varying workloads (without any prior knowledge) and to significantly reduce QoS violations and energy consumption with respect to traditional static approaches.
We address the problem of managing cloud applications, consisting of a set of virtual machines (V... more We address the problem of managing cloud applications, consisting of a set of virtual machines (VMs), characterized by bursty and dynamic workloads, in such a way to provide guarantees on their Quality-of-Services (QoS) and, at the same time, to minimize the energy consumption of the physical infrastructure running them. We propose a fuzzy controller, Fuzzy-Q& E, that is able to allocate to the VMs of each cloud application the minimum amount of physical capacity needed to meet its QoS requirements. In this way, the number of physical resources that must be switched-on at any given time is reduced with respect to the case in which physical machines are statically provisioned and, consequently, less energy is required to run a given cloud workload. We implement a prototype of our controller on a Xen-based testbed, and we perform a set of experiments using an E-Commerce benchmark in which we compare Fuzzy-Q&E against Dyna QoS, a state-of-the-art fuzzy controller for virtualized resources. Experimental results show that Fuzzy-Q&E out performs Dyna QoS both in terms of the ability of meeting the QoS level of the application, and of the amount of physical capacity allocated to each VM.
Federations among sets of Cloud Providers (CPs), whereby a set of CPs agree to mutually use their... more Federations among sets of Cloud Providers (CPs), whereby a set of CPs agree to mutually use their own resources to run the VMs of other CPs, are considered a promising solution to the problem of reducing the energy cost. In this paper, we address the problem of federation formation for a set of CPs, whose solution is necessary to exploit the potential of cloud federations for the reduction of the energy bill. We devise an algorithm, based on cooperative game theory, that can be readily implemented in a distributed fashion, and that allows a set of CPs to cooperatively set up their federations in such a way that their individual profit is increased with respect to the case in which they work in isolation. We show that, by using our algorithm and the proposed CPs' utility function, they are able to self-organize into Nash-stable federations and, by means of iterated executions, to adapt themselves to environmental changes. Numerical results are presented to demonstrate the effectiveness of the proposed algorithm.
phdtheses by Marco Guazzone
Cloud computing is an emerging computing paradigm which is gaining popularity in IT industry for ... more Cloud computing is an emerging computing paradigm which is gaining popularity in IT industry for its appealing property of considering "Everything as a Service". The goal of a cloud infrastructure provider is to maximize its profit by minimizing the amount of violations of Quality-of-Service (QoS) levels agreed with service providers, and, at the same time, by lowering infrastructure costs. Among these costs, the energy consumption induced by the cloud infrastructure, for running cloud services, plays a primary role. Unfortunately, the minimization of QoS violations and, at the same time, the reduction of energy consumption is a conflicting and challenging problem. In this thesis, we propose a framework to automatically manage computing resources of cloud infrastructures in order to simultaneously achieve suitable QoS levels and to reduce as much as possible the amount of energy used for providing services. We show, through simulation, that our approach is able to dynamically adapt to time-varying workloads (without any prior knowledge) and to significantly reduce QoS violations and energy consumption with respect to traditional static approaches.
masterstheses by Marco Guazzone
Questo materiale è reso pubblico per permettere la libera diffusione di lavori accademici e scien... more Questo materiale è reso pubblico per permettere la libera diffusione di lavori accademici e scientifici. Tutti i diritti e i copyright sono da ritenersi associati a MARCO GUAZZONE (l'autore). Tutte le persone che faranno uso di questo documento s'intende che aderiscano ai vincoli e ai termini sul copyright citati in questa pagina. La pubblicazione o l'utilizzo di questo documento a scopo di lucro non può essere effettuata senza esplicito consenso da parte dell'autore.
Papers by Marco Guazzone
Process model discovery covers different methodologies to mine a process model from traces of pro... more Process model discovery covers different methodologies to mine a process model from traces of process executions, and is gaining an important role in Artificial Intelligence research. Current approaches in the area, with few exceptions, focus on determining a model of the flow of actions only. However, in several contexts, (i) restricting the attention to actions is quite limitative, since the effects of such actions have to be analysed, too, and (ii) traces provide additional pieces of information, in the form of states (i.e., values of parameters possibly affected by the actions): for instance, in several medical domains traces include both actions and measurements of patients’ parameters. In this paper, we propose AS-SIM (Action-State SIM), the first approach able to mine a process model which comprehends two distinct classes of nodes, to capture both actions and states.
Future Internet, Nov 28, 2022
This article is an open access article distributed under the terms and conditions of the Creative... more This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY
WQR-Ud
Proceedings of the 12th EAI International Conference on Performance Evaluation Methodologies and Tools, 2019
FemtoClouds are computing platforms, implementing the Fog Computing paradigm, consisting in an en... more FemtoClouds are computing platforms, implementing the Fog Computing paradigm, consisting in an ensemble of heterogeneous mobile devices whose users agree to run the tasks offloaded by other users. FemtoClouds are well suited for the execution of Bag-of-Tasks (BoTs) applications, but, being characterized by high resource heterogeneity and volatility, require the availability of scheduling techniques able to effectively deal with ensembles of independently-owned, heterogeneous devices that can suddenly leave the system. In this paper we propose WQR-UD, an online scheduling algorithm that, thanks to the combination of simple task and device selection policies (that do not require any information concerning the applications and the devices) with effective heterogeneity and volatility tolerance mechanisms, is able to effectively schedule a stream of BoT applications on FemtoCloud systems. We assess the ability of WQR-UD to meet its design goals by running an extensive simulation study for a large set of realistic operational scenarios. Our results clearly indicate that WQR-UD is able to effectively schedule a stream of BoT applications on FemtoCloud systems.
Since its introduction, the Grid computing paradigm has been widely adopted both in scientific an... more Since its introduction, the Grid computing paradigm has been widely adopted both in scientific and also in industrial areas. The main advantage of the Grid computing paradigm is the ability to enable, in a transparent way, the sharing and the coordination of several heterogeneous and large-scale distributed resources belonging to different institutional domains. One of its limitation is the lack of facilities for executing services. In fact, Grid computing has been traditionally used and improved for running computational-intensive or data-intensive applications. A service differs from this kind of applications in that it usually waits for requests from clients and replies with useful information; moreover, a service is typically subjected to some predefined constraints, called Service Level Agreement (SLA), including both temporal and performance restrictions. In this paper we present the TAAROA middleware, a software system that tries to extend the traditional target of the Grid c...
Temporal reasoning and query answering with preferences and probabilities for medical decision support
Expert Systems with Applications, 2022
Online User-driven Task Scheduling for FemtoClouds
2019 Fourth International Conference on Fog and Mobile Edge Computing (FMEC), 2019
In Fog Computing, FemtoClouds are emerging computing systems consisting of a set of heterogeneous... more In Fog Computing, FemtoClouds are emerging computing systems consisting of a set of heterogeneous mobile devices whose users allow to run tasks offloaded by other users. FemtoClouds are well suited to run Bag-of-Tasks (BoTs) applications, but they need effective scheduling algorithms that are able to deal with collections of independently-owned, heterogeneous devices that can suddenly leave the system. In this paper, we present UDFS, an online scheduling algorithm that, by combining knowledge-free task and device selection policies with suitable heterogeneity and volatility tolerance mechanisms, can effectively schedule a stream of BoT applications on FemtoClouds. We evaluate the ability of UDFS to achieve its design goals and to perform better than existing scheduling alternatives, by carrying out a thorough simulation study for a large set of realistic scenarios. Our results indeed show that UDFS can effectively schedule a stream of BoT applications on FemtoClouds, and it can do so more effectively than existing scheduling alternatives.
An educational toolkit for teaching cloud computing
ACM SIGCOMM Computer Communication Review, 2021
In an educational context, experimenting with a real cloud computing platform is very important t... more In an educational context, experimenting with a real cloud computing platform is very important to let students understand the core concepts, methodologies and technologies of cloud computing. However, API heterogeneity of cloud providers complicates the experimentation by forcing students to focus on the use of different APIs, and by hindering the jointly use of different platforms. In this paper, we present EasyCloud, a toolkit enabling the easy and effective use of different cloud platforms. In particular, we describe its features, architecture, scalability, and use in our cloud computing courses, as well as the pedagogical insights we learnt over the years.
Cloud computing is an emerging computing paradigm which is gaining popularity in IT industry for ... more Cloud computing is an emerging computing paradigm which is gaining popularity in IT industry for its appealing property of considering “Everything as a Service”. The goal of a cloud infrastructure provider is to maximize its profit by minimizing the amount of violations of Quality-of-Service (QoS) levels agreed with service providers, and, at the same time, by lowering infrastructure costs. Among these costs, the energy consumption induced by the cloud infrastructure, for running cloud services, plays a primary role. Unfortunately, the minimization of QoS violations and, at the same time, the reduction of energy consumption is a conflicting and challenging problem. In this thesis, we propose a framework to automatically manage computing resources of cloud infrastructures in order to simultaneously achieve suitable QoS levels and to reduce as much as possible the amount of energy used for providing services. We show, through simulation, that our approach is able to dynamically adapt ...
Copyright e Licenza Questo materiale è reso pubblico per permettere la libera diffusione di lavor... more Copyright e Licenza Questo materiale è reso pubblico per permettere la libera diffusione di lavori accademici e scientifici. Tutti i diritti e i copyright sono da ritenersi associati a MARCO GUAZZONE (l'autore). Tutte le persone che faranno uso di questo documento s'intende che aderiscano ai vincoli e ai termini sul copyright citati in questa pagina. La pubblicazione o l'utilizzo di questo documento a scopo di lucro non può essere effettuata senza esplicito consenso da parte dell'autore. Licenza Caratterizzazione del Carico per Sistemi GRID di MARCO GUAZZONE è sotto licenza Creative Commons Attribution-Noncommercial-Share Alike 2.5 Italy License Tu sei libero: • di riprodurre, distribuire, comunicare al pubblico, esporre in pubblico, rappresentare, eseguire e recitare quest'opera; • di modificare quest'opera. Alle seguenti condizioni: • Attribuzione. Devi attribuire la paternità dell'opera nei modi indicati dall'autore o da chi ti ha dato l'opera in licenza e in modo tale da non suggerire che essi avallino te o il modo in cui tu usi l'opera. • Non commerciale. Non puoi usare quest'opera per fini commerciali. i • Condividi allo stesso modo. Se alteri o trasformi quest'opera, o se la usi per crearne un'altra, puoi distribuire l'opera risultante solo con una licenza identica o equivalente a questa. Ogni volta che usi o distribuisci quest'opera, devi farlo secondo i termini di questa licenza, che va comunicata con chiarezza. In ogni caso, puoi concordare col titolare dei diritti utilizzi di quest'opera non consentiti da questa licenza. Questa licenza lascia impregiudicati i diritti morali. Limitazione di responsabilità Le utilizzazioni consentite dalla legge sul diritto d'autore e gli altri diritti non sono in alcun modo limitati da quanto sopra. ii A Lorenza, per la sua infinita pazienza e per la felicità che mi dona ogni giorno. Al Prof. C. Anglano e al Dr. M. Canonico, per tutto l'aiuto che mi hanno dato, l'entusiasmo che mi hanno trasmesso, e l'umanità che mi hanno dimostrato. Al Prof. A. Bobbio, per i suoi utilissimi consigli sulla Statistica. Ai miei genitori.
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articles by Marco Guazzone
inproceedings by Marco Guazzone
phdtheses by Marco Guazzone
masterstheses by Marco Guazzone
Papers by Marco Guazzone