| Records |
| Author |
Chierichetti, Flavio; Lattanzi, Silvio; Mari, Federico; Panconesi, Alessandro |
| Title |
On Placing Skips Optimally in Expectation |
Type |
Conference Article |
| Year |
2008 |
Publication |
Web Search and Web Data Mining (WSDM 2008) |
Abbreviated Journal |
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| Volume |
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Issue |
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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. |
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| Publisher |
Acm |
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Najork, M.; Broder, A.Z.; Chakrabarti, S. |
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yes |
Call Number  |
Sapienza @ mari @ ChiLatMar08 |
Serial |
94 |
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| Author |
Coppo, Mario; Dezani-Ciancaglini, Mariangiola; Giovannetti, Elio; Salvo, Ivano |
| Title |
Mobility Types for Mobile Processes in Mobile Ambients |
Type |
Journal Article |
| Year |
2003 |
Publication |
Electr. Notes Theor. Comput. Sci. |
Abbreviated Journal |
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| Volume |
78 |
Issue |
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Pages |
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| Abstract |
We present an ambient-like calculus in which the open capability is dropped, and a new form of “lightweight  process mobility is introduced. The calculus comes equipped with a type system that allows the kind of values exchanged in communications and the access and mobility properties of processes to be controlled. A type inference procedure determines the “minimal  requirements to accept a system or a component as well typed. This gives a kind of principal typing. As an expressiveness test, we show that some well known calculi of concurrency and mobility can be encoded in our calculus in a natural way. |
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Approved |
yes |
| Call Number |
Sapienza @ mari @ Coppo-Dezani-Giovannetti-Salvo:03 |
Serial |
74 |
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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 |
| Title |
Risk analysis via heterogeneous models of SCADA interconnecting Power Grids and Telco networks |
Type |
Conference Article |
| Year |
2009 |
Publication |
Proceedings of Fourth International Conference on Risks and Security of Internet and Systems (CRiSIS) |
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Issue |
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Pages |
90-97 |
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| 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. |
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Fourth International Conference on Risks and Security of Internet and Systems (CRiSIS) |
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Approved |
yes |
| Call Number |
Sapienza @ mari @ crisis09 |
Serial |
17 |
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| Author |
Mazzini, Silvia; Puri, Stefano; Mari, Federico; Melatti, Igor; Tronci, Enrico |
| Title |
Formal Verification at System Level |
Type |
Conference Article |
| Year |
2009 |
Publication |
In: DAta Systems In Aerospace (DASIA), Org. EuroSpace, Canadian Space Agency, CNES, ESA, EUMETSAT. Instanbul, Turkey, EuroSpace |
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System Level Analysis calls for a language comprehensible to experts with different background and yet precise enough to support meaningful analyses. SysML is emerging as an effective balance between such conflicting goals. In this paper we outline some the results obtained as for SysML based system level functional formal verification by an ESA/ESTEC study, with a collaboration among INTECS and La Sapienza University of Roma. The study focuses on SysML based system level functional requirements techniques. |
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Approved |
yes |
| Call Number |
Sapienza @ mari @ Dasia09 |
Serial |
20 |
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| Author |
Cavaliere, Federico; Mari, Federico; Melatti, Igor; Minei, Giovanni; Salvo, Ivano; Tronci, Enrico; Verzino, Giovanni; Yushtein, Yuri |
| Title |
Model Checking Satellite Operational Procedures |
Type |
Conference Article |
| Year |
2011 |
Publication |
DAta Systems In Aerospace (DASIA), Org. EuroSpace, Canadian Space Agency, CNES, ESA, EUMETSAT. San Anton, Malta, EuroSpace. |
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We present a model checking approach for the automatic verification of satellite operational procedures (OPs). Building a model for a complex system as a satellite is a hard task. We overcome this obstruction by using a suitable simulator (SIMSAT) for the satellite. Our approach aims at improving OP quality assurance by automatic exhaustive exploration of all possible simulation scenarios. Moreover, our solution decreases OP verification costs by using a model checker (CMurphi) to automatically drive the simulator. We model OPs as user-executed programs observing the simulator telemetries and sending telecommands to the simulator. In order to assess feasibility of our approach we present experimental results on a simple meaningful scenario. Our results show that we can save up to 90% of verification time. |
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Approved |
yes |
| Call Number |
Sapienza @ mari @ Dasia11 |
Serial |
13 |
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| Author |
Della Penna, Giuseppe; Di Marco, Antinisca; Intrigila, Benedetto; Melatti, Igor; Pierantonio, Alfonso |
| Title |
Xere: Towards a Natural Interoperability between XML and ER Diagrams |
Type |
Conference Article |
| Year |
2003 |
Publication |
Fundamental Approaches to Software Engineering, 6th International Conference, FASE 2003, Held as Part of the Joint European Conferences on Theory and Practice of Software, ETAPS 2003, Warsaw, Poland, April 7-11, 2003, Proceedings |
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Issue |
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Pages |
356-371 |
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| Abstract |
XML (eXtensible Markup Language) is becoming the standard format for documents on Internet and is widely used to exchange data. Often, the relevant information contained in XML documents needs to be also stored in legacy databases (DB) in order to integrate the new data with the pre-existing ones. In this paper, we introduce a technique for the automatic XML-DB integration, which we call Xere. In particular we present, as the first step of Xere, the mapping algorithm which allows the translation of XML Schemas into Entity-Relationship diagrams. |
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Springer |
Place of Publication |
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Editor |
Pezzè, M. |
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Series Title |
Lecture Notes in Computer Science |
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| Series Volume |
2621 |
Series Issue |
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Edition |
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| ISSN |
3-540-00899-3 |
ISBN |
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Approved |
yes |
| Call Number |
Sapienza @ mari @ Ddimp03 |
Serial |
86 |
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| Author |
Della Penna, Giuseppe; Di Marco, Antinisca; Intrigila, Benedetto; Melatti, Igor; Pierantonio, Alfonso |
| Title |
Interoperability mapping from XML schemas to ER diagrams |
Type |
Journal Article |
| Year |
2006 |
Publication |
Data Knowl. Eng. |
Abbreviated Journal |
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| Volume |
59 |
Issue |
1 |
Pages |
166-188 |
| Keywords |
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| Abstract |
The eXtensible Markup Language (XML) is a de facto standard on the Internet and is now being used to exchange a variety of data structures. This leads to the problem of efficiently storing, querying and retrieving a great amount of data contained in XML documents. Unfortunately, XML data often need to coexist with historical data. At present, the best solution for storing XML into pre-existing data structures is to extract the information from the XML documents and adapt it to the data structures’ logical model (e.g., the relational model of a DBMS). In this paper, we introduce a technique called Xere (XML entity–relationship exchange) to assist the integration of XML data with other data sources. To this aim, we present an algorithm that maps XML schemas into entity–relationship diagrams, discuss its soundness and completeness and show its implementation in XSLT. |
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Elsevier Science Publishers B. V. |
Place of Publication |
Amsterdam, The Netherlands, The Netherlands |
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Edition |
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| ISSN |
0169-023x |
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Approved |
yes |
| Call Number |
Sapienza @ mari @ Ddimp06 |
Serial |
77 |
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| Author |
Della Penna, Giuseppe; Intrigila, Benedetto; Melatti, Igor; Minichino, Michele; Ciancamerla, Ester; Parisse, Andrea; Tronci, Enrico; Venturini Zilli, Marisa |
| Title |
Automatic Verification of a Turbogas Control System with the Mur$\varphi$ Verifier |
Type |
Conference Article |
| Year |
2003 |
Publication |
Hybrid Systems: Computation and Control, 6th International Workshop, HSCC 2003 Prague, Czech Republic, April 3-5, 2003, Proceedings |
Abbreviated Journal |
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Issue |
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Pages |
141-155 |
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| Abstract |
Automatic analysis of Hybrid Systems poses formidable challenges both from a modeling as well as from a verification point of view. We present a case study on automatic verification of a Turbogas Control System (TCS) using an extended version of the Mur$\varphi$ verifier. TCS is the heart of ICARO, a 2MW Co-generative Electric Power Plant. For large hybrid systems, as TCS is, the modeling effort accounts for a significant part of the whole verification activity. In order to ease our modeling effort we extended the Mur$\varphi$ verifier by importing the C language long double type (finite precision real numbers) into it. We give experimental results on running our extended Mur$\varphi$ on our TCS model. For example using Mur$\varphi$ we were able to compute an admissible range of values for the variation speed of the user demand of electric power to the turbogas. |
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Thesis |
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Springer |
Place of Publication |
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Editor |
Maler, O.; Pnueli, A. |
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Summary Language |
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Original Title |
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Series Title |
Lecture Notes in Computer Science |
Abbreviated Series Title |
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| Series Volume |
2623 |
Series Issue |
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Edition |
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| ISSN |
3-540-00913-2 |
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Approved |
yes |
| Call Number |
Sapienza @ mari @ Dimmcptz03 |
Serial |
88 |
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| Author |
Della Penna, Giuseppe; Magazzeni, Daniele; Tofani, Alberto; Intrigila, Benedetto; Melatti, Igor; Tronci, Enrico |
| Title |
Automated Generation of Optimal Controllers through Model Checking Techniques |
Type |
Conference Article |
| Year |
2006 |
Publication |
Icinco-Icso |
Abbreviated Journal |
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| Volume |
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Issue |
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Pages |
26-33 |
| Keywords |
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| Abstract |
We present a methodology for the synthesis of controllers, which exploits (explicit) model checking techniques. That is, we can cope with the systematic exploration of a very large state space. This methodology can be applied to systems where other approaches fail. In particular, we can consider systems with an highly non-linear dynamics and lacking a uniform mathematical description (model). We can also consider situations where the required control action cannot be specified as a local action, and rather a kind of planning is required. Our methodology individuates first a raw optimal controller, then extends it to obtain a more robust one. A case study is presented which considers the well known truck-trailer obstacle avoidance parking problem, in a parking lot with obstacles on it. The complex non-linear dynamics of the truck-trailer system, within the presence of obstacles, makes the parking problem extremely hard. We show how, by our methodology, we can obtain optimal controllers with different degrees of robustness. |
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INSTICC Press |
Place of Publication |
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Editor |
Andrade-Cetto, J.; Ferrier, J.-L.; Pereira, J. M. C. D.; Filipe, J. |
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972-8865-59-7 |
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Approved |
yes |
| Call Number |
Sapienza @ mari @ Dimmtt06 |
Serial |
79 |
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| Author |
Della Penna, Giuseppe; Intrigila, Benedetto; Melatti, Igor; Tronci, Enrico |
| Title |
Exploiting Hub States in Automatic Verification |
Type |
Conference Article |
| Year |
2005 |
Publication |
Automated Technology for Verification and Analysis: Third International Symposium, ATVA 2005, Taipei, Taiwan, October 4-7, 2005, Proceedings |
Abbreviated Journal |
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Issue |
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Pages |
54-68 |
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| Abstract |
In this paper we present a new algorithm to counteract state explosion when using Explicit State Space Exploration to verify protocol-like systems. We sketch the implementation of our algorithm within the Caching Mur$\varphi$ verifier and give experimental results showing its effectiveness. We show experimentally that, when memory is a scarce resource, our algorithm improves on the time performances of Caching Mur$\varphi$ verification algorithm, saving between 16% and 68% (45% on average) in computation time. |
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Thesis |
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Springer |
Place of Publication |
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Editor |
D.A. Peled; Y.-K. Tsay |
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Series Title |
Lecture Notes in Computer Science |
Abbreviated Series Title |
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| Series Volume |
3707 |
Series Issue |
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Edition |
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| ISSN |
3-540-29209-8 |
ISBN |
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Approved |
yes |
| Call Number |
Sapienza @ mari @ Dimt04 |
Serial |
83 |
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