2002
Book
Unknown
Marte: Appuntamento con il destino - Il pianeta rosso e l'uomo: esplorazione, progetti, immagini
Anselmo L.
Abstract non disponibile
Anselmo L.
Abstract non disponibile
See at: CNR ExploRA
2002
Book
Unknown
A first approach to the integration of low and high level processing modules for character recognition in ancient printed documents
Tonazzini A., Bedini L.
An abstract is not availableSource: Trivandrum: Transworld Research Network, 2002
Tonazzini A., Bedini L.
An abstract is not availableSource: Trivandrum: Transworld Research Network, 2002
See at: CNR ExploRA
2001
Book
Unknown
A learner-independent evaluation of the usefulness of statistical phrases for automated text categorization
Caropreso M. F., Matwin S., Sebastiani F.
In this work we investigate the usefulness of {em $n$-grams} for document indexing in text categorization (TC). We call $n$-gram a set $g_k$ of $n$ word stems, and we say that $g_k$ occurs in a document $d_j$ when a sequence of words appears in $d_j$ that, after stop word removal and stemming, consists exactly of the $n$ stems in $g_k$, in some order. Previous researches have investigated the use of $n$-grams (or some variant of them) in the context of specific learning algorithms, and thus have not obtained general answers on their usefulness for TC. In this work we investigate the usefulness of $n$-grams in TC independently of any specific learning algorithm. We do so by applying feature selection to the pool of all $k$-grams ($kleq n$), and checking how many $n$-grams score high enough to be selected in the top $sigma$ $k$-grams. We report the results of our experiments, using various feature selection measures and varying values of $sigma$, performed on the {sc Reuters-21578} standard TC benchmark. We also report results of making actual use of the selected $n$-grams in the context of a linear classifier induced by means of the Rocchio method.
Caropreso M. F., Matwin S., Sebastiani F.
In this work we investigate the usefulness of {em $n$-grams} for document indexing in text categorization (TC). We call $n$-gram a set $g_k$ of $n$ word stems, and we say that $g_k$ occurs in a document $d_j$ when a sequence of words appears in $d_j$ that, after stop word removal and stemming, consists exactly of the $n$ stems in $g_k$, in some order. Previous researches have investigated the use of $n$-grams (or some variant of them) in the context of specific learning algorithms, and thus have not obtained general answers on their usefulness for TC. In this work we investigate the usefulness of $n$-grams in TC independently of any specific learning algorithm. We do so by applying feature selection to the pool of all $k$-grams ($kleq n$), and checking how many $n$-grams score high enough to be selected in the top $sigma$ $k$-grams. We report the results of our experiments, using various feature selection measures and varying values of $sigma$, performed on the {sc Reuters-21578} standard TC benchmark. We also report results of making actual use of the selected $n$-grams in the context of a linear classifier induced by means of the Rocchio method.
See at: CNR ExploRA
2005
Book
Unknown
Gestione efficiente dei dati prodotti dai sistemi di scansione tridimensionale
Scopigno R.
La ricerca inerente i modelli tridimensionali per le applicazioni ai Beni Culturali (BC) si pone come obiettivo primario lo sviluppo e la sperimentazione di strumenti informatici che mettano a disposizione degli operatori del settore BC un nuovo mezzo di conoscenza: il modello digitale tridimensionale (3D) di un oggetto di interesse storico e/o artistico. Per modello 3D non si intendono, ovviamente, una o più immagini dell'oggetto o, tantomeno, un'animazione ottenuta 'montando' opportunamente immagini fotografiche dello stesso (come è possibile realizzare con strumenti quali QuickTimeVR). Un modello 3D è una rappresentazione digitale fedele e misurabile dell'oggetto in esame ottenuta mediante la rappresentazione esplicita delle sue caratteristiche di forma e colore.Source: Borgo San Lorenzo: All'Insegna del Giglio, 2005
Scopigno R.
La ricerca inerente i modelli tridimensionali per le applicazioni ai Beni Culturali (BC) si pone come obiettivo primario lo sviluppo e la sperimentazione di strumenti informatici che mettano a disposizione degli operatori del settore BC un nuovo mezzo di conoscenza: il modello digitale tridimensionale (3D) di un oggetto di interesse storico e/o artistico. Per modello 3D non si intendono, ovviamente, una o più immagini dell'oggetto o, tantomeno, un'animazione ottenuta 'montando' opportunamente immagini fotografiche dello stesso (come è possibile realizzare con strumenti quali QuickTimeVR). Un modello 3D è una rappresentazione digitale fedele e misurabile dell'oggetto in esame ottenuta mediante la rappresentazione esplicita delle sue caratteristiche di forma e colore.Source: Borgo San Lorenzo: All'Insegna del Giglio, 2005
See at: CNR ExploRA | vcg.isti.cnr.it
2005
Book
Unknown
Verso l' interoperabilità semantica
Signore O.
Condividere la conoscenza sul web significa poter disporre di strumenti e tecnologie che consentano di esprimere i contenuti, strutturarli e presentarli in modo adeguato, rendendone esplicita la semantica e consentendo la fruizione dell' informazione a tutti, indipendentemente dal particolare retroterra culturale e dal contesto tecnologico. Nel contesto dei beni culturali, in cui coesistono tradizioni e impostazioni culturali ben radicate e difficilmente modificabili, è importante raggiungere l' interoperabilità semantica, abbattendo le differenze culturali, senza imporre a nessuno di rinunciare alle proprie. Questa problematica sembra trovare possibili soluzioni nel contesto dell' attività di ricerca nota come Semantic Web, che coagula competenze e interessi diversi, perseguendo l' obiettivo di realizzare un Web in cui assume grande rilevanza l' interazione tra macchine, e le informazioni, arricchite da metadati, possono essere utilizzate in maniera più efficace da agenti software intelligenti.
Signore O.
Condividere la conoscenza sul web significa poter disporre di strumenti e tecnologie che consentano di esprimere i contenuti, strutturarli e presentarli in modo adeguato, rendendone esplicita la semantica e consentendo la fruizione dell' informazione a tutti, indipendentemente dal particolare retroterra culturale e dal contesto tecnologico. Nel contesto dei beni culturali, in cui coesistono tradizioni e impostazioni culturali ben radicate e difficilmente modificabili, è importante raggiungere l' interoperabilità semantica, abbattendo le differenze culturali, senza imporre a nessuno di rinunciare alle proprie. Questa problematica sembra trovare possibili soluzioni nel contesto dell' attività di ricerca nota come Semantic Web, che coagula competenze e interessi diversi, perseguendo l' obiettivo di realizzare un Web in cui assume grande rilevanza l' interazione tra macchine, e le informazioni, arricchite da metadati, possono essere utilizzate in maniera più efficace da agenti software intelligenti.
See at: CNR ExploRA | www.minervaeurope.org
2006
Book
Unknown
Similarity Search: the metric space approach
Zezula P., Amato G., Dohnal V., Bako M.
In the Information Society, information holds the master key to economic inuence and success. But the usefulness of information depends critically upon its quality and the speed at which it can be transferred. In domains as diverse as multimedia, molecular biology, computer-aided design and marketing and purchasing assistance, the number of data resources is growing rapidly, both with regard to database size and the variety of forms in which data comes packaged. To cope with the resulting information overkill, it is vital to nd tools to search these resources efciently and effectively. Hence the intense interest in Computer Science in searching digital data repositories. But traditional retrieval techniques, typically based upon sorting routines and hash tables, are not appropriate for a growing number of newly-emerging data domains. More exible methods must be found instead which take into account the needs of particular users and particular application domains. This book is about nding efcient ways to locate user-relevant information in collections of objects which have been quantied using a pairwise distance measure between object instances. It is written in direct response to recent advances in computing, communication and storage which have led to the current ood of digital libraries, data warehouses and the limitless heterogeneity of Internet resources. The scale of the problem can be gauged by noting that almost everything we see, hear, read, write or measure will soon be available to computerized information systems. In such an environment, varied data modalities such as multimedia objects, scientic observations and measurements, statistical analyses and many others, are massively extending more traditional attribute-like data types.Source: New York: Springer, 2006
Zezula P., Amato G., Dohnal V., Bako M.
In the Information Society, information holds the master key to economic inuence and success. But the usefulness of information depends critically upon its quality and the speed at which it can be transferred. In domains as diverse as multimedia, molecular biology, computer-aided design and marketing and purchasing assistance, the number of data resources is growing rapidly, both with regard to database size and the variety of forms in which data comes packaged. To cope with the resulting information overkill, it is vital to nd tools to search these resources efciently and effectively. Hence the intense interest in Computer Science in searching digital data repositories. But traditional retrieval techniques, typically based upon sorting routines and hash tables, are not appropriate for a growing number of newly-emerging data domains. More exible methods must be found instead which take into account the needs of particular users and particular application domains. This book is about nding efcient ways to locate user-relevant information in collections of objects which have been quantied using a pairwise distance measure between object instances. It is written in direct response to recent advances in computing, communication and storage which have led to the current ood of digital libraries, data warehouses and the limitless heterogeneity of Internet resources. The scale of the problem can be gauged by noting that almost everything we see, hear, read, write or measure will soon be available to computerized information systems. In such an environment, varied data modalities such as multimedia objects, scientic observations and measurements, statistical analyses and many others, are massively extending more traditional attribute-like data types.Source: New York: Springer, 2006
See at: CNR ExploRA
2006
Book
Unknown
Position paper on space debris mitigation
Bonnal C., Flury W., Hussey J., Anselmo L.
For several decades, orbital debris have been identified as a serious concern! This orbital debris potentially threatens future space missions, mainly in Low Earth Orbits and in Geostationary Earth Orbit, due to the risk of high energy collisions with valuable spacecraft. Orbital debris comprise the non-functional hardware orbiting the Earth, decommissioned spacecraft, spent upper stages, operational debris or residues from collisions; 94% of catalogued orbital objects are nowadays orbital debris. A complete presentation of the topic has been published with the year 2000 revision of the IAA Position Paper on Orbital Debris1. There are only very limited ways to improve the risks or effects of collisions: . Removal of large potential colliders does not seem practically feasible today, due to operational and programmatic constraints, . Collision avoidance is possible only with large catalogued debris, but requires access to precise orbital data for the largest debris, thanks to propagation of orbital tracks based on large observation facilities . Shielding of critical spacecraft is possible up to a low energy limit only: debris larger than 1 or 2 cm impacting an active spacecraft may have very deadly effect . Mitigation is by far the most efficient strategy: limiting the number of orbital debris in the critical orbital zones is the most efficient strategy for long term stability of the orbital population The study led by an ad-hoc group of specialists from the International Academy of Astronautics (IAA) under the leadership of Commission V, has established a number of clear recommendations aiming at promoting long term orbital debris mitigation. The study covered both the spacecraft and the launchers topics, through two independent subworking groups, whose findings are presented separately in this document. Their major recommendations are very similar: . There shall be no generation of operational debris: a space mission shall be clean, generating no long-term orbital debris such as clamp bands, fairings, optics protections, . There shall be no risk of explosion following end of mission: any spacecraft or upper stage left in orbit shall be 'passivated', i.e. its internal energy shall be eliminated: residual propellants shall be dumped, pressurants shall be depleted, batteries safed, etc. As per beginning of 2005, more than 180 in-orbit explosions have occurred, generating about 40% of the orbital debris population: it can easily be avoided. . Two orbital regions shall be protected, due to their economical importance: Low Earth Region, ranging up to 2000 km altitude, and Geostationary Earth Orbit. A clear motto has been identified as a long term strategy: there shall be no orbital debris creation within these two protected regions. As this recommendation may not sound realistic currently, it may be replaced in the coming decade by there shall be no long lived orbital debris creation within the two protected regions.Source: Noordwijk: ESA Publication Division, 2006
Bonnal C., Flury W., Hussey J., Anselmo L.
For several decades, orbital debris have been identified as a serious concern! This orbital debris potentially threatens future space missions, mainly in Low Earth Orbits and in Geostationary Earth Orbit, due to the risk of high energy collisions with valuable spacecraft. Orbital debris comprise the non-functional hardware orbiting the Earth, decommissioned spacecraft, spent upper stages, operational debris or residues from collisions; 94% of catalogued orbital objects are nowadays orbital debris. A complete presentation of the topic has been published with the year 2000 revision of the IAA Position Paper on Orbital Debris1. There are only very limited ways to improve the risks or effects of collisions: . Removal of large potential colliders does not seem practically feasible today, due to operational and programmatic constraints, . Collision avoidance is possible only with large catalogued debris, but requires access to precise orbital data for the largest debris, thanks to propagation of orbital tracks based on large observation facilities . Shielding of critical spacecraft is possible up to a low energy limit only: debris larger than 1 or 2 cm impacting an active spacecraft may have very deadly effect . Mitigation is by far the most efficient strategy: limiting the number of orbital debris in the critical orbital zones is the most efficient strategy for long term stability of the orbital population The study led by an ad-hoc group of specialists from the International Academy of Astronautics (IAA) under the leadership of Commission V, has established a number of clear recommendations aiming at promoting long term orbital debris mitigation. The study covered both the spacecraft and the launchers topics, through two independent subworking groups, whose findings are presented separately in this document. Their major recommendations are very similar: . There shall be no generation of operational debris: a space mission shall be clean, generating no long-term orbital debris such as clamp bands, fairings, optics protections, . There shall be no risk of explosion following end of mission: any spacecraft or upper stage left in orbit shall be 'passivated', i.e. its internal energy shall be eliminated: residual propellants shall be dumped, pressurants shall be depleted, batteries safed, etc. As per beginning of 2005, more than 180 in-orbit explosions have occurred, generating about 40% of the orbital debris population: it can easily be avoided. . Two orbital regions shall be protected, due to their economical importance: Low Earth Region, ranging up to 2000 km altitude, and Geostationary Earth Orbit. A clear motto has been identified as a long term strategy: there shall be no orbital debris creation within these two protected regions. As this recommendation may not sound realistic currently, it may be replaced in the coming decade by there shall be no long lived orbital debris creation within the two protected regions.Source: Noordwijk: ESA Publication Division, 2006
See at: CNR ExploRA
2006
Book
Open Access
The digital library manifesto
Candela L., Castelli D., Ioannidis Y., Koutrika G., Pagano P., Ross S., Schek H., Schuldt H.
The term 'Digital Libraries' corresponds to a very complex notion with several diverse aspects and cannot be captured by a simple definition. A comprehensive representation of Digital Libraries encapsulating all potential perspectives is required. This has led to the drafting of 'The Digital Library Manifesto', whose aim is to set the foundations and identify the cornerstone concepts within the universe of Digital Libraries, facilitating the integration of research and proposing better ways of developing appropriate systems. The 'Digital Library Manifesto' exploits the collective understanding that has been acquired on Digital Libraries by several previous efforts by European research groups active in the Digital Library field for many years, both within the DELOS Network of Excellence and outside, as well as by other groups around the world. Its role is one of a springboard for future work.Source: Pisa: DELOS: a Network of Excellence on Digital Libraries, 2006
Candela L., Castelli D., Ioannidis Y., Koutrika G., Pagano P., Ross S., Schek H., Schuldt H.
The term 'Digital Libraries' corresponds to a very complex notion with several diverse aspects and cannot be captured by a simple definition. A comprehensive representation of Digital Libraries encapsulating all potential perspectives is required. This has led to the drafting of 'The Digital Library Manifesto', whose aim is to set the foundations and identify the cornerstone concepts within the universe of Digital Libraries, facilitating the integration of research and proposing better ways of developing appropriate systems. The 'Digital Library Manifesto' exploits the collective understanding that has been acquired on Digital Libraries by several previous efforts by European research groups active in the Digital Library field for many years, both within the DELOS Network of Excellence and outside, as well as by other groups around the world. Its role is one of a springboard for future work.Source: Pisa: DELOS: a Network of Excellence on Digital Libraries, 2006
See at:
146.48.87.21 
| CNR ExploRA
2002
Book
Restricted
GaliLEO. A simulation tool for traffic on LEO satellite constellations. Presentation of the architecture
Celandroni N., Ferro E., Potortì F., Franck L.
Complex communication systems where satellite links are involved are difficult to test and tune up without the help of simulation tools. First of all, using satellites is very expensive - the satellite time spent in testing and tuning-up the system must thus be as short as possible. Second, during the performance evaluation in a real environment it is not always possible to find the right amount of traffic, and the most appropriate traffic pattern and data aggregation that will put the system under the maximum amount of stress so that its limits can be validated. When satellite constellations are involved, rather than single satellites, these problems are enormously exacerbated, to the point that in all but very particular cases it is practically impossible for the researcher to do tests on satellite constellations. It is therefore necessary to use some kind of simulation tool. The array of required features for the tool is very broad. The basic feature is that of making it possible to describe the constellation topology, and the position of earth terminals. Satellite may have different capabilities, in term of number and characteristics of intersatellite links, spot topology and behaviour, and on-board processing abilities. Many types of routing algorithms are under study, some of which allow for dynamic rerouting based on nodes' perceived congestion or on quality of service requests. Also, it should be possible to analyse channel allocation algorithms for the up-down links, including frequency reuse algorithms. The traffic generation choice should be broad and easily extensible, allowing for both fine control on single connections and generation of background traffic for loading the satellite network. Finally, a rich set of statistic collection and analysis tools should be available.
Celandroni N., Ferro E., Potortì F., Franck L.
Complex communication systems where satellite links are involved are difficult to test and tune up without the help of simulation tools. First of all, using satellites is very expensive - the satellite time spent in testing and tuning-up the system must thus be as short as possible. Second, during the performance evaluation in a real environment it is not always possible to find the right amount of traffic, and the most appropriate traffic pattern and data aggregation that will put the system under the maximum amount of stress so that its limits can be validated. When satellite constellations are involved, rather than single satellites, these problems are enormously exacerbated, to the point that in all but very particular cases it is practically impossible for the researcher to do tests on satellite constellations. It is therefore necessary to use some kind of simulation tool. The array of required features for the tool is very broad. The basic feature is that of making it possible to describe the constellation topology, and the position of earth terminals. Satellite may have different capabilities, in term of number and characteristics of intersatellite links, spot topology and behaviour, and on-board processing abilities. Many types of routing algorithms are under study, some of which allow for dynamic rerouting based on nodes' perceived congestion or on quality of service requests. Also, it should be possible to analyse channel allocation algorithms for the up-down links, including frequency reuse algorithms. The traffic generation choice should be broad and easily extensible, allowing for both fine control on single connections and generation of background traffic for loading the satellite network. Finally, a rich set of statistic collection and analysis tools should be available.
See at:
www.wiley.com 
| CNR ExploRA
2001
Book
Unknown
Colonizzare la Galassia - La fisica dei viaggi interstellari
Anselmo L.
An abstract is not available.
Anselmo L.
An abstract is not available.
See at: CNR ExploRA
2001
Book
Unknown
Cross-language information retrieval and evaluation
Peters C.
The objective of the Cross-Language Evaluation Forum (CLEF) is to develop and maintain an infrastructure for the testing and evaluation of information retrieval systems operating on European languages, in both monolingual and cross-language contexts,and to create test-suites of reusable data that can be employed by system developers for benchmarking purposes. The first CLEF evaluation campaign started in early 2000 and ended with a workshop in Lisbon, Portugal, 22-23 September 2000. This volume constitutes the proceedings of the workshop and also provides a record of the results of the campaign. It consists of two parts and an appendix. The first part reflects the presentations and discussions on the topic of evaluation for crosslanguage information retrieval systems during the first day of the workshop, whereas the second contains papers from the individual participating groups reporting their experiments and analysing their results. The appendix presents the evaluation techniques and measures used to derive the results and provides the run statistics. The aim of this Introduction is to present the main issues discussed at the workshop and also to provide the reader with the necessary background to the experiments through a description of the tasks set for CLEF 2000. In conclusion, our plans for future CLEF campaigns are outlined.
Peters C.
The objective of the Cross-Language Evaluation Forum (CLEF) is to develop and maintain an infrastructure for the testing and evaluation of information retrieval systems operating on European languages, in both monolingual and cross-language contexts,and to create test-suites of reusable data that can be employed by system developers for benchmarking purposes. The first CLEF evaluation campaign started in early 2000 and ended with a workshop in Lisbon, Portugal, 22-23 September 2000. This volume constitutes the proceedings of the workshop and also provides a record of the results of the campaign. It consists of two parts and an appendix. The first part reflects the presentations and discussions on the topic of evaluation for crosslanguage information retrieval systems during the first day of the workshop, whereas the second contains papers from the individual participating groups reporting their experiments and analysing their results. The appendix presents the evaluation techniques and measures used to derive the results and provides the run statistics. The aim of this Introduction is to present the main issues discussed at the workshop and also to provide the reader with the necessary background to the experiments through a description of the tasks set for CLEF 2000. In conclusion, our plans for future CLEF campaigns are outlined.
See at: CNR ExploRA
2001
Book
Unknown
Dependability evaluation
Arlat J., Bondavalli A., Di Giandomenico F., Jarboui M. T., Jenn E., Kanoun K., Mura I., Powell D.
This chapter summarises the dependability evaluation efforts carried out within the GUARDS project. The three-pronged modelling and evaluation study encompasses the three complementary viewpoints already identified in Chapter 1, Section 1.9.2, namely: focused, abstract, and detailed modelling. They are successively described in the following section.
Arlat J., Bondavalli A., Di Giandomenico F., Jarboui M. T., Jenn E., Kanoun K., Mura I., Powell D.
This chapter summarises the dependability evaluation efforts carried out within the GUARDS project. The three-pronged modelling and evaluation study encompasses the three complementary viewpoints already identified in Chapter 1, Section 1.9.2, namely: focused, abstract, and detailed modelling. They are successively described in the following section.
See at: CNR ExploRA
2001
Book
Unknown
Error processing and fault treatment
Bondavalli A., Chiaradonna S., Di Giandomenico F., Grandoni F., Powell D., Rabéjac C.
An abstract is not available.
Bondavalli A., Chiaradonna S., Di Giandomenico F., Grandoni F., Powell D., Rabéjac C.
An abstract is not available.
See at: CNR ExploRA
2001
Book
Unknown
See at: CNR ExploRA
2001
Book
Restricted
GaliLEO: a simulation tool for LEO satellite constellations
Franck L., Potortì F.
We present Galileo, a simulator for the transmission of both connection-oriented and connectionless traffic over a constellation of LEO/MEO (Low / Medium Earth Orbit) satellites. Its scope is limited to the satellites and the stations accessing them, without any modelling of the terrestrial network, but inside this scope the goal is to study the performance of satellite-based communication networks from as many as possible points of view. Typical applications include simulation of access techniques, routing policies, fault management. The simulator is written in Java, and it makes use of dynamic loading to easily integrate user-written modules. A draft manual is available, and a preliminary version of the program will be published by the end of 2000.
Franck L., Potortì F.
We present Galileo, a simulator for the transmission of both connection-oriented and connectionless traffic over a constellation of LEO/MEO (Low / Medium Earth Orbit) satellites. Its scope is limited to the satellites and the stations accessing them, without any modelling of the terrestrial network, but inside this scope the goal is to study the performance of satellite-based communication networks from as many as possible points of view. Typical applications include simulation of access techniques, routing policies, fault management. The simulator is written in Java, and it makes use of dynamic loading to easily integrate user-written modules. A draft manual is available, and a preliminary version of the program will be published by the end of 2000.
See at:
www.wkap.nl | CNR ExploRA
2001
Book
Unknown
Interactive query expansion with automatically generated category-specific thesauri
Sebastiani F.
The categorization of documents into subject-specific categories is a useful enhancement for large document collections addressed by information retrieval systems, as a user can first browse a category tree in search of the category that best matches her interests, and then issue a query for more specific documents ``from within the category''. This approach combines two modalities in information seeking that are most popular in Web-based search engines, i.e. category-based site browsing (as exemplified by e.g. {sc Yahoo}$^{smallsc TM}$) and keyword-based document querying (as exemplified by e.g. {sc AltaVista}$^{smallsc TM}$). Appropriate query expansion tools need to be provided, though, in order to allow the user to incrementally refine her query through further retrieval passes, thus allowing the system to produce a series of subsequent document rankings that hopefully converge to the user's expected ranking. In this work we propose that automatically generated, category-specific ``associative'' thesauri be used for such purpose. We discuss a method for their generation, and discuss how the thesaurus specific to a given category may usefully be endowed with "gateways" to the thesauri specific to its parent and children categories
Sebastiani F.
The categorization of documents into subject-specific categories is a useful enhancement for large document collections addressed by information retrieval systems, as a user can first browse a category tree in search of the category that best matches her interests, and then issue a query for more specific documents ``from within the category''. This approach combines two modalities in information seeking that are most popular in Web-based search engines, i.e. category-based site browsing (as exemplified by e.g. {sc Yahoo}$^{smallsc TM}$) and keyword-based document querying (as exemplified by e.g. {sc AltaVista}$^{smallsc TM}$). Appropriate query expansion tools need to be provided, though, in order to allow the user to incrementally refine her query through further retrieval passes, thus allowing the system to produce a series of subsequent document rankings that hopefully converge to the user's expected ranking. In this work we propose that automatically generated, category-specific ``associative'' thesauri be used for such purpose. We discuss a method for their generation, and discuss how the thesaurus specific to a given category may usefully be endowed with "gateways" to the thesauri specific to its parent and children categories
See at: CNR ExploRA
2001
Book
Unknown
See at: CNR ExploRA
2001
Book
Unknown
Luna: l'evoluzione di un Sogno - Passato, presente e futuro dell'esplorazione lunare
Anselmo L.
Esplorazione lunare: Analisi e prospettive future
Anselmo L.
Esplorazione lunare: Analisi e prospettive future
See at: CNR ExploRA