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Author Brizzolari, Francesco; Melatti, Igor; Tronci, Enrico; Della Penna, Giuseppe pdf  doi
openurl 
  Title Disk Based Software Verification via Bounded Model Checking Type Conference Article
  Year (up) 2007 Publication APSEC '07: Proceedings of the 14th Asia-Pacific Software Engineering Conference Abbreviated Journal  
  Volume Issue Pages 358-365  
  Keywords  
  Abstract One of the most successful approach to automatic software verification is SAT based bounded model checking (BMC). One of the main factors limiting the size of programs that can be automatically verified via BMC is the huge number of clauses that the backend SAT solver has to process. In fact, because of this, the SAT solver may easily run out of RAM. We present two disk based algorithms that can considerably decrease the number of clauses that a BMC backend SAT solver has to process in RAM. Our experimental results show that using our disk based algorithms we can automatically verify programs that are out of reach for RAM based BMC.  
  Address  
  Corporate Author Thesis  
  Publisher IEEE Computer Society Place of Publication Washington, DC, USA Editor  
  Language Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 0-7695-3057-5 ISBN Medium  
  Area Expedition Conference  
  Notes Approved yes  
  Call Number Sapienza @ mari @ Bmtd07 Serial 76  
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Author Intrigila, Benedetto; Melatti, Igor; Tofani, Alberto; Macchiarelli, Guido pdf  doi
openurl 
  Title Computational models of myocardial endomysial collagen arrangement Type Journal Article
  Year (up) 2007 Publication Computer Methods and Programs in Biomedicine Abbreviated Journal  
  Volume 86 Issue 3 Pages 232-244  
  Keywords  
  Abstract Collagen extracellular matrix is one of the factors related to high passive stiffness of cardiac muscle. However, the architecture and the mechanical aspects of the cardiac collagen matrix are not completely known. In particular, endomysial collagen contribution to the passive mechanics of cardiac muscle as well as its micro anatomical arrangement is still a matter of debate. In order to investigate mechanical and structural properties of endomysial collagen, we consider two alternative computational models of some specific aspects of the cardiac muscle. These two models represent two different views of endomysial collagen distribution: (1) the traditional view and (2) a new view suggested by the data obtained from scanning electron microscopy (SEM) in NaOH macerated samples (a method for isolating collagen from the other tissue). We model the myocardial tissue as a net of spring elements representing the cardiomyocytes together with the endomysial collagen distribution. Each element is a viscous elastic spring, characterized by an elastic and a viscous constant. We connect these springs to imitate the interconnections between collagen fibers. Then we apply to the net of springs some external forces of suitable magnitude and direction, obtaining an extension of the net itself. In our setting, the ratio forces magnitude /net extension is intended to model the stress /strain ratio of a microscopical portion of the myocardial tissue. To solve the problem of the correct identification of the values of the different parameters involved, we use an artificial neural network approach. In particular, we use this technique to learn, given a distribution of external forces, the elastic constants of the springs needed to obtain a desired extension as an equilibrium position. Our experimental findings show that, in the model of collagen distribution structured according to the new view, a given stress /strain ratio (of the net of springs, in the sense specified above) is obtained with much smaller (w.r.t. the other model, corresponding to the traditional view) elasticity constants of the springs. This seems to indicate that by an appropriate structure, a given stiffness of the myocardial tissue can be obtained with endomysial collagen fibers of much smaller size.  
  Address  
  Corporate Author Thesis  
  Publisher Elsevier North-Holland, Inc. Place of Publication New York, NY, USA Editor  
  Language Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 0169-2607 ISBN Medium  
  Area Expedition Conference  
  Notes Approved yes  
  Call Number Sapienza @ mari @ Imtm07 Serial 82  
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Author Della Penna, Giuseppe; Magazzeni, Daniele; Tofani, Alberto; Intrigila, Benedetto; Melatti, Igor; Tronci, Enrico pdf  doi
openurl 
  Title Automatic Synthesis of Robust Numerical Controllers Type Conference Article
  Year (up) 2007 Publication Icas '07 Abbreviated Journal  
  Volume Issue Pages 4  
  Keywords  
  Abstract A major problem of numerical controllers is their robustness, i.e. the state read from the plant may not be in the controller table, although it may be close to some states in the table. For continuous systems, this problem is typically handled by interpolation techniques. Unfortunately, when the plant contains both continuous and discrete variables, the interpolation approach does not work well. To cope with this kind of systems, we propose a general methodology that exploits explicit model checking in an innovative way to automatically synthesize a (time-) optimal numerical controller from a plant specification and apply an optimized strengthening algorithm only on the most significant states, in order to reach an acceptable robustness degree. We implemented all the algorithms within our CGMurphi tool, an extension of the well-known CMurphi verifier, and tested the effectiveness of our approach by applying it to the well-known truck and trailer obstacles avoidance problem.  
  Address  
  Corporate Author Thesis  
  Publisher IEEE Computer Society Place of Publication Editor  
  Language Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 0-7695-2859-5 ISBN Medium  
  Area Expedition Conference  
  Notes Approved yes  
  Call Number Sapienza @ mari @ Dmtimt07 Serial 89  
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Author Mari, Federico; Tronci, Enrico pdf  doi
openurl 
  Title CEGAR Based Bounded Model Checking of Discrete Time Hybrid Systems Type Conference Article
  Year (up) 2007 Publication Hybrid Systems: Computation and Control (HSCC 2007) Abbreviated Journal  
  Volume Issue Pages 399-412  
  Keywords Model Checking, Abstraction, CEGAR, SAT, Hybrid Systems, DTHS  
  Abstract Many hybrid systems can be conveniently modeled as Piecewise Affine Discrete Time Hybrid Systems PA-DTHS. As well known Bounded Model Checking (BMC) for such systems comes down to solve a Mixed Integer Linear Programming (MILP) feasibility problem. We present a SAT based BMC algorithm for automatic verification of PA-DTHSs. Using Counterexample Guided Abstraction Refinement (CEGAR) our algorithm gradually transforms a PA-DTHS verification problem into larger and larger SAT problems. Our experimental results show that our approach can handle PA-DTHSs that are more then 50 times larger than those that can be handled using a MILP solver.  
  Address  
  Corporate Author Thesis  
  Publisher Springer Place of Publication Editor Bemporad, A.; Bicchi, A.; Buttazzo, G.C.  
  Language Summary Language Original Title  
  Series Editor Series Title Lecture Notes in Computer Science Abbreviated Series Title  
  Series Volume 4416 Series Issue Edition  
  ISSN ISBN Medium  
  Area Expedition Conference  
  Notes Approved yes  
  Call Number Sapienza @ mari @ MarTro07 Serial 92  
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Author Della Penna, Giuseppe; Magazzeni, Daniele; Tofani, Alberto; Intrigila, Benedetto; Melatti, Igor; Tronci, Enrico pdf  doi
openurl 
  Title Automated Generation Of Optimal Controllers Through Model Checking Techniques Type Book Chapter
  Year (up) 2008 Publication Informatics in Control Automation and Robotics. Selected Papers from ICINCO 2006 Abbreviated Journal  
  Volume Issue Pages 107-119  
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  Abstract  
  Address  
  Corporate Author Thesis  
  Publisher Springer Place of Publication Editor  
  Language Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN ISBN Medium  
  Area Expedition Conference  
  Notes Approved yes  
  Call Number Sapienza @ mari @ Dmtmt08 Serial 26  
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Author Cesta, Amedeo; Finzi, Alberto; Fratini, Simone; Orlandini, Andrea; Tronci, Enrico pdf  openurl
  Title Merging Planning, Scheduling & Verification – A Preliminary Analysis Type Conference Article
  Year (up) 2008 Publication In Proc. of 10th ESA Workshop on Advanced Space Technologies for Robotics and Automation (ASTRA) Abbreviated Journal  
  Volume Issue Pages  
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  Abstract  
  Address  
  Corporate Author Thesis  
  Publisher Place of Publication Editor  
  Language Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN ISBN Medium  
  Area Expedition Conference  
  Notes Approved yes  
  Call Number Sapienza @ mari @ Astra08 Serial 24  
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Author Cesta, Amedeo; Finzi, Alberto; Fratini, Simone; Orlandini, Andrea; Tronci, Enrico pdf  openurl
  Title Validation and Verification Issues in a Timeline-based Planning System Type Conference Article
  Year (up) 2008 Publication In E-Proc. of ICAPS Workshop on Knowledge Engineering for Planning and Scheduling Abbreviated Journal  
  Volume Issue Pages  
  Keywords  
  Abstract One of the key points to take into account to foster effective introduction of AI planning and scheduling systems in real world is to develop end user trust in the related technologies. Automated planning and scheduling systems often brings solutions to the users which are neither “obvious†nor immediately acceptable for them. This is due to the ability of these tools to take into account quite an amount of temporal and causal constraints and to employ resolution processes often designed to optimize the solution with respect to non trivial evaluation functions. To increase technology trust, the study of tools for verifying and validating plans and schedules produced by AI systems might be instrumental. In general, validation and verification techniques represent a needed complementary technology in developing domain independent architectures for automated problem solving. This paper presents a preliminary report of the issues concerned with the use of two software tools for formal verification of finite state systems to the validation of the solutions produced by MrSPOCK, a recent effort for building a timeline based planning tool in an ESA project.  
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  Publisher Place of Publication Editor  
  Language Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN ISBN Medium  
  Area Expedition Conference  
  Notes Approved yes  
  Call Number Sapienza @ mari @ Keps08 Serial 25  
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Author Mari, Federico; Melatti, Igor; Salvo, Ivano; Tronci, Enrico; Alvisi, Lorenzo; Clement, Allen; Li, Harry pdf  doi
openurl 
  Title Model Checking Nash Equilibria in MAD Distributed Systems Type Conference Article
  Year (up) 2008 Publication FMCAD '08: Proceedings of the 2008 International Conference on Formal Methods in Computer-Aided Design Abbreviated Journal  
  Volume Issue Pages 1-8  
  Keywords Model Checking, MAD Distributed System, Nash Equilibrium  
  Abstract We present a symbolic model checking algorithm for verification of Nash equilibria in finite state mechanisms modeling Multiple Administrative Domains (MAD) distributed systems. Given a finite state mechanism, a proposed protocol for each agent and an indifference threshold for rewards, our model checker returns PASS if the proposed protocol is a Nash equilibrium (up to the given indifference threshold) for the given mechanism, FAIL otherwise. We implemented our model checking algorithm inside the NuSMV model checker and present experimental results showing its effectiveness for moderate size mechanisms. For example, we can handle mechanisms which corresponding normal form games would have more than $10^20$ entries. To the best of our knowledge, no model checking algorithm for verification of mechanism Nash equilibria has been previously published.  
  Address  
  Corporate Author Thesis  
  Publisher IEEE Press Place of Publication Piscataway, NJ, USA Editor Cimatti, A.; Jones, R.  
  Language Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 978-1-4244-2735-2 ISBN Medium  
  Area Expedition Conference  
  Notes Approved yes  
  Call Number Sapienza @ mari @ MarMelSalTroAlvCle08 Serial 93  
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Author Chierichetti, Flavio; Lattanzi, Silvio; Mari, Federico; Panconesi, Alessandro pdf  doi
openurl 
  Title On Placing Skips Optimally in Expectation Type Conference Article
  Year (up) 2008 Publication Web Search and Web Data Mining (WSDM 2008) Abbreviated Journal  
  Volume Issue Pages 15-24  
  Keywords Information Retrieval  
  Abstract We study the problem of optimal skip placement in an inverted list. Assuming the query distribution to be known in advance, we formally prove that an optimal skip placement can be computed quite efficiently. Our best algorithm runs in time O(n log n), n being the length of the list. The placement is optimal in the sense that it minimizes the expected time to process a query. Our theoretical results are matched by experiments with a real corpus, showing that substantial savings can be obtained with respect to the tra- ditional skip placement strategy, that of placing consecutive skips, each spanning sqrt(n) many locations.  
  Address  
  Corporate Author Thesis  
  Publisher Acm Place of Publication Editor Najork, M.; Broder, A.Z.; Chakrabarti, S.  
  Language Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN ISBN Medium  
  Area Expedition Conference  
  Notes Approved yes  
  Call Number Sapienza @ mari @ ChiLatMar08 Serial 94  
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Author Bobbio, Andrea; Ciancamerla, Ester; Di Blasi, Saverio; Iacomini, Alessandro; Mari, Federico; Melatti, Igor; Minichino, Michele; Scarlatti, Alessandro; Tronci, Enrico; Terruggia, Roberta; Zendri, Emilio pdf  doi
openurl 
  Title Risk analysis via heterogeneous models of SCADA interconnecting Power Grids and Telco networks Type Conference Article
  Year (up) 2009 Publication Proceedings of Fourth International Conference on Risks and Security of Internet and Systems (CRiSIS) Abbreviated Journal  
  Volume Issue Pages 90-97  
  Keywords  
  Abstract The automation of power grids by means of supervisory control and data acquisition (SCADA) systems has led to an improvement of power grid operations and functionalities but also to pervasive cyber interdependencies between power grids and telecommunication networks. Many power grid services are increasingly depending upon the adequate functionality of SCADA system which in turn strictly depends on the adequate functionality of its communication infrastructure. We propose to tackle the SCADA risk analysis by means of different and heterogeneous modeling techniques and software tools. We demonstrate the applicability of our approach through a case study on an actual SCADA system for an electrical power distribution grid. The modeling techniques we discuss aim at providing a probabilistic dependability analysis, followed by a worst case analysis in presence of malicious attacks and a real-time performance evaluation.  
  Address  
  Corporate Author Thesis  
  Publisher Place of Publication Editor  
  Language Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN ISBN Medium  
  Area Expedition Conference Fourth International Conference on Risks and Security of Internet and Systems (CRiSIS)  
  Notes Approved yes  
  Call Number Sapienza @ mari @ crisis09 Serial 17  
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