2004
Conference article
Restricted
A unifying framework for flexible information access in taxonomy-based sources
Tzitzikas Y, Meghini C, Spyratos N
A taxonomy-based source consists of a taxonomy and a database storing objects that are indexed in terms of the taxonomy. For this kind of sources, we describe a flexible interaction scheme that allows users to retrieve the objects of interest without having to be familiar with the terms of the taxonomy or with the supported query language. Specifically we describe an interaction manager whose functionality unifies several well-known interaction schemes including query by example, answer enlargement/reduction, query relaxation/ restriction, index relaxation/contraction, feedback and adaptation mechanisms.
Tzitzikas Y, Meghini C, Spyratos N
A taxonomy-based source consists of a taxonomy and a database storing objects that are indexed in terms of the taxonomy. For this kind of sources, we describe a flexible interaction scheme that allows users to retrieve the objects of interest without having to be familiar with the terms of the taxonomy or with the supported query language. Specifically we describe an interaction manager whose functionality unifies several well-known interaction schemes including query by example, answer enlargement/reduction, query relaxation/ restriction, index relaxation/contraction, feedback and adaptation mechanisms.
2004
Conference article
Restricted
Querying articulated sources
Meghini C, Tzitzikas Y
In this study we address the problem of answering queries over information sources storing objects which are indexed by terms arranged in a taxonomy. We examine query languages of different expressivity and sources with different kinds of taxonomies. In the simplest kind, the taxonomy includes just term-to-term subsumption links. This case is used as a basis for further developments, in which we consider taxonomies consisting of term-to-queries links. An algorithm for query evaluation is presented for this kind of taxonomies, and it is shown that the addition of negation to the query language leads to intractability. Finally, query-to-query taxonomies are considered.
Meghini C, Tzitzikas Y
In this study we address the problem of answering queries over information sources storing objects which are indexed by terms arranged in a taxonomy. We examine query languages of different expressivity and sources with different kinds of taxonomies. In the simplest kind, the taxonomy includes just term-to-term subsumption links. This case is used as a basis for further developments, in which we consider taxonomies consisting of term-to-queries links. An algorithm for query evaluation is presented for this kind of taxonomies, and it is shown that the addition of negation to the query language leads to intractability. Finally, query-to-query taxonomies are considered.
2004
Conference article
Restricted
Towards a generalized interaction scheme for information access
Tzitzikas Y, Meghini C, Spyratos N
We introduce the formal framework of a generalized interaction scheme for information access between users and information sources. Within this framework we describe an interaction manager which supports more complex interaction schemes than those that are supported by existing systems, including: query by example, answer enlargement/reduction, query relaxation/restriction, index relaxation/contraction, 'relevance' feedback, and adaptation facilities. We give the foundations of this interaction manager from a mathematical point of view, in terms of an abstract view of an information source.
Tzitzikas Y, Meghini C, Spyratos N
We introduce the formal framework of a generalized interaction scheme for information access between users and information sources. Within this framework we describe an interaction manager which supports more complex interaction schemes than those that are supported by existing systems, including: query by example, answer enlargement/reduction, query relaxation/restriction, index relaxation/contraction, 'relevance' feedback, and adaptation facilities. We give the foundations of this interaction manager from a mathematical point of view, in terms of an abstract view of an information source.
2006
Journal article
Restricted
A unified interaction scheme for information sources
Tzitzikas Y, Meghini C, Spyratos N
Commonly, for retrieving the desired information from an information source (knowledge base or information base), the user has to use the query language that is provided by the system. This is a big barrier for many ordinary users and the resulting interaction style is rather inflexible. In this paper we give the theoretical foundations of an interaction scheme that allows users to retrieve the objects of interest without having to be familiar with the conceptual schema of the source or with the supported query language. Specifically, we describe an interaction manager that provides a quite flexible interaction scheme by unifying several well-known interaction schemes. Furthermore, we show how this scheme can be applied to taxonomy-based sources by providing all needed algorithms and reporting their computational complexity.Source: JOURNAL OF INTELLIGENT INFORMATION SYSTEMS, vol. 26 (issue 1), pp. 75-93
DOI: 10.1007/s10844-006-5452-0
Metrics:
Tzitzikas Y, Meghini C, Spyratos N
Commonly, for retrieving the desired information from an information source (knowledge base or information base), the user has to use the query language that is provided by the system. This is a big barrier for many ordinary users and the resulting interaction style is rather inflexible. In this paper we give the theoretical foundations of an interaction scheme that allows users to retrieve the objects of interest without having to be familiar with the conceptual schema of the source or with the supported query language. Specifically, we describe an interaction manager that provides a quite flexible interaction scheme by unifying several well-known interaction schemes. Furthermore, we show how this scheme can be applied to taxonomy-based sources by providing all needed algorithms and reporting their computational complexity.Source: JOURNAL OF INTELLIGENT INFORMATION SYSTEMS, vol. 26 (issue 1), pp. 75-93
DOI: 10.1007/s10844-006-5452-0
Metrics:
See at:
Journal of Intelligent Information Systems 
| CNR IRIS | CNR IRIS | www.springerlink.com
2006
Conference article
Restricted
Abduction for extending incomplete information sources
Meghini C, Tzitzikas Y, Spyratos N
The extraction of information from a source containing term-classified objects is plagued with uncertainty, due, among other things, to the possible incompleteness of the source index. To overcome this incompleteness, the study proposes to expand the index of the source, in a way that is as reasonable as possible with respect to the original classification of objects. By equating reasonableness with logical implication, the sought expansion turns out to be an explanation of the index, captured by abduction. We study the general problem of query evaluation on the extended information source, providing a polynomial time algorithm which tackles the general case, in which no hypothesis is made on the structure of the taxonomy. We then specialize the algorithm for two well-know structures: DAGs and trees, showing that each specialization results in a more efficient query evaluation.DOI: 10.1007/11752912_28
Metrics:
Meghini C, Tzitzikas Y, Spyratos N
The extraction of information from a source containing term-classified objects is plagued with uncertainty, due, among other things, to the possible incompleteness of the source index. To overcome this incompleteness, the study proposes to expand the index of the source, in a way that is as reasonable as possible with respect to the original classification of objects. By equating reasonableness with logical implication, the sought expansion turns out to be an explanation of the index, captured by abduction. We study the general problem of query evaluation on the extended information source, providing a polynomial time algorithm which tackles the general case, in which no hypothesis is made on the structure of the taxonomy. We then specialize the algorithm for two well-know structures: DAGs and trees, showing that each specialization results in a more efficient query evaluation.DOI: 10.1007/11752912_28
Metrics:
See at:
doi.org | CNR IRIS | CNR IRIS | link.springer.com
2006
Conference article
Open Access
Preference-based query tuning through refinement/enlargement in a formal context
Spyratos N, Meghini C
The user of an information system rarely knows exactly what he is looking for, but once shown a piece of information he can quickly tell whether it is what he needs. Query tuning is the process of searching for the query that best approximates the information need of the user. Typically, navigation and querying are two completely separate processes, and the user usually has to switch often from one to the other--a painstaking process producing a frustrating experience. In this paper, we propose an approach to query tuning that integrates navigation and querying into a single process, thus leading to a more flexible and more user friendly method of query tuning. The proposed approach is based on formal concept analysis, and models the directory of an information source as a formal context in which the underlying concept lattice serves for navigation and the attributes of the formal context serve for query formulation. In order to support the user in coping with a possibly overwhelming number of alternative query tunings, preferences are introduced.DOI: 10.1007/11663881_16
Project(s): Network of Excellence on Digital Libraries
Metrics:
Spyratos N, Meghini C
The user of an information system rarely knows exactly what he is looking for, but once shown a piece of information he can quickly tell whether it is what he needs. Query tuning is the process of searching for the query that best approximates the information need of the user. Typically, navigation and querying are two completely separate processes, and the user usually has to switch often from one to the other--a painstaking process producing a frustrating experience. In this paper, we propose an approach to query tuning that integrates navigation and querying into a single process, thus leading to a more flexible and more user friendly method of query tuning. The proposed approach is based on formal concept analysis, and models the directory of an information source as a formal context in which the underlying concept lattice serves for navigation and the attributes of the formal context serve for query formulation. In order to support the user in coping with a possibly overwhelming number of alternative query tunings, preferences are introduced.DOI: 10.1007/11663881_16
Project(s): Network of Excellence on Digital Libraries
Metrics:
See at:
www.nmis.isti.cnr.it 
| doi.org | CNR IRIS | CNR IRIS | www.springerlink.com
2007
Conference article
Open Access
Computing intensions of digital library collections
Meghini C, Spyratos N
We model a Digital Library as a formal context in which objects are documents and attributes are terms describing documents contents. A formal concept is very close to the notion of a collection: the concept extent is the extension of the collection; the concept intent consists of a set of terms, the collection intension. The collection intension can be viewed as a simple conjunctive query which evaluates precisely to the extension. However, for certain collections no concept may exist, in which case the concept that best approximates the extension must be used. In so doing, we may end up with a too imprecise concept, in case too many documents denoted by the intension are outside the extension. We then look for a more precise intension by exploring 3 different query languages: conjunctive queries with negation; disjunctions of negationfree conjunctive queries; and disjunctions of conjunctive queries with negation. We show that a precise description can always be found in one of these languages for any set of documents. However, when disjunction is introduced, uniqueness of the solution is lost. In order to deal with this problem, we define a preferential criterion on queries, based on the conciseness of their expression. We then show that minimal queries are hard to find in the last 2 of the three languages above.DOI: 10.1007/978-3-540-70901-5_5
Metrics:
Meghini C, Spyratos N
We model a Digital Library as a formal context in which objects are documents and attributes are terms describing documents contents. A formal concept is very close to the notion of a collection: the concept extent is the extension of the collection; the concept intent consists of a set of terms, the collection intension. The collection intension can be viewed as a simple conjunctive query which evaluates precisely to the extension. However, for certain collections no concept may exist, in which case the concept that best approximates the extension must be used. In so doing, we may end up with a too imprecise concept, in case too many documents denoted by the intension are outside the extension. We then look for a more precise intension by exploring 3 different query languages: conjunctive queries with negation; disjunctions of negationfree conjunctive queries; and disjunctions of conjunctive queries with negation. We show that a precise description can always be found in one of these languages for any set of documents. However, when disjunction is introduced, uniqueness of the solution is lost. In order to deal with this problem, we define a preferential criterion on queries, based on the conciseness of their expression. We then show that minimal queries are hard to find in the last 2 of the three languages above.DOI: 10.1007/978-3-540-70901-5_5
Metrics:
See at:
www.nmis.isti.cnr.it | doi.org | CNR IRIS | CNR IRIS | www.springerlink.com
2003
Conference article
Restricted
An Abduction-based Method for Index Relaxation in Taxonomy-based Sources
Meghini C, Tzitzikas Y, Spiratos N
The extraction of information from a source containing termclassified objects is plagued with uncertainty. In the present paper we deal with this uncertainty in a qualitative way. We view an information source as an agent, operating according to an open world philosophy. The agent knows some facts, but is aware that there could be other facts, compatible with the known ones, that might hold as well, although they are not captured for lack of knowledge. These facts are, indeed, ossibilities. We view possibilities as explanations and resort to abduction in order to define precisely the ossibilities that we want our system to be able to handle. We introduce an operation that extends a taxonomy-based source with possibilities, and then study the property of this operation from a mathematical point of view.DOI: 10.1007/978-3-540-45138-9_53
Metrics:
Meghini C, Tzitzikas Y, Spiratos N
The extraction of information from a source containing termclassified objects is plagued with uncertainty. In the present paper we deal with this uncertainty in a qualitative way. We view an information source as an agent, operating according to an open world philosophy. The agent knows some facts, but is aware that there could be other facts, compatible with the known ones, that might hold as well, although they are not captured for lack of knowledge. These facts are, indeed, ossibilities. We view possibilities as explanations and resort to abduction in order to define precisely the ossibilities that we want our system to be able to handle. We introduce an operation that extends a taxonomy-based source with possibilities, and then study the property of this operation from a mathematical point of view.DOI: 10.1007/978-3-540-45138-9_53
Metrics:
See at:
doi.org | CNR IRIS | CNR IRIS | link.springer.com
2003
Conference article
Restricted
Ostensive Automatic Schema Mapping for Taxonomy-based Peer-to-Peer Systems
Tzitzikas Y, Meghini C
This paper considers Peer-to-Peer systems in which peers employ taxonomies for describing the contents of their objects and for formulating semantic-based queries to the other peers of the system. As each peer can use its own taxonomy, peers are equipped with intertaxonomy mappings in order to carry out the required translation tasks. As these systems are ad-hoc, the peers should be able to create or revise these mappings on demand and at run-time. For this reason, we introduce an ostensive data-driven method for automatic mapping and specialize it for the case of taxonomies.
Tzitzikas Y, Meghini C
This paper considers Peer-to-Peer systems in which peers employ taxonomies for describing the contents of their objects and for formulating semantic-based queries to the other peers of the system. As each peer can use its own taxonomy, peers are equipped with intertaxonomy mappings in order to carry out the required translation tasks. As these systems are ad-hoc, the peers should be able to create or revise these mappings on demand and at run-time. For this reason, we introduce an ostensive data-driven method for automatic mapping and specialize it for the case of taxonomies.
2003
Conference article
Restricted
Query Evaluation in Peer-to-Peer Networks of Taxonomy-based Sources
Meghini C, Tzitzikas Y
We consider the problem of query evaluation in Peer-to-Peer (P2P) systems that support semantic-based retrieval services.We confine ourselves to the case where the peers employ taxonomies for describing the contents of the objects, and articulations, i.e. inter-taxonomy mappings, for bridging the inevitable naming, granularity and contextual heterogeneities that may exist between the taxonomies of the sources. We identify two basic query evaluation approaches: one based on query rewriting, the other based on direct query evaluation. For each approach we present a centralized and a decentralized algorithm for carrying out the query evaluation task. Finally, we present a qualitative comparison of these algorithms and discuss further optimizations. Correctness of the algorithms presented is based on a mathematical analysis of the problem.
Meghini C, Tzitzikas Y
We consider the problem of query evaluation in Peer-to-Peer (P2P) systems that support semantic-based retrieval services.We confine ourselves to the case where the peers employ taxonomies for describing the contents of the objects, and articulations, i.e. inter-taxonomy mappings, for bridging the inevitable naming, granularity and contextual heterogeneities that may exist between the taxonomies of the sources. We identify two basic query evaluation approaches: one based on query rewriting, the other based on direct query evaluation. For each approach we present a centralized and a decentralized algorithm for carrying out the query evaluation task. Finally, we present a qualitative comparison of these algorithms and discuss further optimizations. Correctness of the algorithms presented is based on a mathematical analysis of the problem.
2003
Conference article
Restricted
Taxonomy-based Conceptual Modeling for Peer-to-Peer Networks
Tzitzikas Y, Meghini C, Spyratos N
We present a taxonomy-based conceptual modeling approach for building P2P systems that support semantic-based retrieval services. We adopt this simple conceptual modeling approach due to its advantages in terms of ease of use, uniformity, scalability and efficiency. As each peer uses its own taxonomy for describing the contents of its objects and for formulating queries to the other peers, peers are equipped with articulations, i.e. inter-taxonomy mappings, in order to carry out the required translation tasks. We describe various kinds of articulations and we give the semantics for each case. Then we discuss the differences between query evaluation in mediators and query evaluation in P2P systems, and finally we identify issues for further research.DOI: 10.1007/978-3-540-39648-2_35
Metrics:
Tzitzikas Y, Meghini C, Spyratos N
We present a taxonomy-based conceptual modeling approach for building P2P systems that support semantic-based retrieval services. We adopt this simple conceptual modeling approach due to its advantages in terms of ease of use, uniformity, scalability and efficiency. As each peer uses its own taxonomy for describing the contents of its objects and for formulating queries to the other peers, peers are equipped with articulations, i.e. inter-taxonomy mappings, in order to carry out the required translation tasks. We describe various kinds of articulations and we give the semantics for each case. Then we discuss the differences between query evaluation in mediators and query evaluation in P2P systems, and finally we identify issues for further research.DOI: 10.1007/978-3-540-39648-2_35
Metrics:
See at:
doi.org | CNR IRIS | CNR IRIS | link.springer.com
2008
Journal article
Restricted
Synthesizing monadic predicates
Meghini C, Spyratos N
We study the problem of determining a concise, quantifier-free monadic predicate for a given set of objects in a given interpretation. We ad- dress both DNF and CNF predicates, as well as important sub-languages thereof. The problem is formalized as the search of a minimal element in a set of predicates equipped with a binary relation. We show that the problem has always a solution, that finding a minimal solution is always hard, but much harder when neither the given set of objects nor its com- plement are the extent of a formal concept (in the sense of Formal Concept Analysis).Source: JOURNAL OF LOGIC AND COMPUTATION, vol. 18 (issue 6), pp. 831-847
DOI: 10.1093/logcom/exn006
Metrics:
Meghini C, Spyratos N
We study the problem of determining a concise, quantifier-free monadic predicate for a given set of objects in a given interpretation. We ad- dress both DNF and CNF predicates, as well as important sub-languages thereof. The problem is formalized as the search of a minimal element in a set of predicates equipped with a binary relation. We show that the problem has always a solution, that finding a minimal solution is always hard, but much harder when neither the given set of objects nor its com- plement are the extent of a formal concept (in the sense of Formal Concept Analysis).Source: JOURNAL OF LOGIC AND COMPUTATION, vol. 18 (issue 6), pp. 831-847
DOI: 10.1093/logcom/exn006
Metrics:
See at:
Journal of Logic and Computation | CNR IRIS | CNR IRIS | www.ucm.es
2010
Conference article
Restricted
A functionality perspective on digital library interoperability
Meghini C, Athanasopoulos G, Fox E, Ioannidis Y, Kakaletris G, Manola N, Rauber A, Soergel D
Digital Library (DL) interoperability requires addressing a variety of issues associated with functionality. We report on the analysis and solutions identified by the Functionality Working Group of the DL.org project during its deliberations on DL interoperability. Ultimately, we hope that work based on our perspective will lead to improved architectures and software, as well as to greater interoperability, for next-generation DL systems.DOI: 10.1007/978-3-642-15464-5_43
Metrics:
Meghini C, Athanasopoulos G, Fox E, Ioannidis Y, Kakaletris G, Manola N, Rauber A, Soergel D
Digital Library (DL) interoperability requires addressing a variety of issues associated with functionality. We report on the analysis and solutions identified by the Functionality Working Group of the DL.org project during its deliberations on DL interoperability. Ultimately, we hope that work based on our perspective will lead to improved architectures and software, as well as to greater interoperability, for next-generation DL systems.DOI: 10.1007/978-3-642-15464-5_43
Metrics:
See at:
doi.org | CNR IRIS | CNR IRIS | www.springerlink.com
2010
Conference article
Restricted
Modelling digital libraries based on logic
Meghini C, Spyratos N, Sugibuchi T
We present a data model for digital libraries supporting identification, description and discovery of digital objects. The model is formalized as a first-order theory, certain models of which correspond to the intuitive notion of digital library. Our main objective is to lay the foundations for the design of an API offering the above functionality. Additionally, we use our formal framework to discuss the adequacy of the Resource Description Framework with respect to the requirements of digital libraries.DOI: 10.1007/978-3-642-15464-5_2
Project(s): Advanced Search Services and Enhanced Technological Solutions for the European Digital Library
Metrics:
Meghini C, Spyratos N, Sugibuchi T
We present a data model for digital libraries supporting identification, description and discovery of digital objects. The model is formalized as a first-order theory, certain models of which correspond to the intuitive notion of digital library. Our main objective is to lay the foundations for the design of an API offering the above functionality. Additionally, we use our formal framework to discuss the adequacy of the Resource Description Framework with respect to the requirements of digital libraries.DOI: 10.1007/978-3-642-15464-5_2
Project(s): Advanced Search Services and Enhanced Technological Solutions for the European Digital Library
Metrics:
See at:
doi.org | CNR IRIS | CNR IRIS | www.springerlink.com
2007
Conference article
Open Access
Leveraging on associations -- a new challenge for digital libraries
Meghini C, Spyratos N, Doerr M
Decades of research have been devoted to the goal of creating systems which integrate information into a global knowledge network. On the other side, Digital libraries have not overcome the traditional paradigm of delivering a document as ultimate objective. This paper argues that next-generation DL services must be built on accessing associations implicit or explicit in document collections and their metadata. It suggests a new approach to leverage associations based on (i) generic core ontologies of relationship and co-reference links (ii) semi-automatic maintenance of co-reference links by a new kind of service, and (iii) public engagement in the creation and development of the emerging association network.
Meghini C, Spyratos N, Doerr M
Decades of research have been devoted to the goal of creating systems which integrate information into a global knowledge network. On the other side, Digital libraries have not overcome the traditional paradigm of delivering a document as ultimate objective. This paper argues that next-generation DL services must be built on accessing associations implicit or explicit in document collections and their metadata. It suggests a new approach to leverage associations based on (i) generic core ontologies of relationship and co-reference links (ii) semi-automatic maintenance of co-reference links by a new kind of service, and (iii) public engagement in the creation and development of the emerging association network.
2007
Conference article
Open Access
Sharing co-reference knowledge for data integration
Meghini C, Nicolas S, Martin D
Data integration requires solving the basic problem of determining whether two identifiers from different terminologies co-refer, that is refer to the same object. The problem arises in many different contexts and provokes intense philosophical debate, yet it has never been addressed in a systematic way from an information system point of view. This paper presents a formal model of co-reference, as a relation which is part of the reality created by language structures. A complete mathematical characterization of co-reference is derived. A service handling co-reference knowledge is then introduced, and the basic functionality of such a service is formally defined in terms of a certain mathematical structure. Finally, the implementation of the service is studied from the computational point of view, and effcient algorithms for carrying out the basic operations of the service are provided.
Meghini C, Nicolas S, Martin D
Data integration requires solving the basic problem of determining whether two identifiers from different terminologies co-refer, that is refer to the same object. The problem arises in many different contexts and provokes intense philosophical debate, yet it has never been addressed in a systematic way from an information system point of view. This paper presents a formal model of co-reference, as a relation which is part of the reality created by language structures. A complete mathematical characterization of co-reference is derived. A service handling co-reference knowledge is then introduced, and the basic functionality of such a service is formally defined in terms of a certain mathematical structure. Finally, the implementation of the service is studied from the computational point of view, and effcient algorithms for carrying out the basic operations of the service are provided.
See at:
CNR IRIS | www.delos.info | CNR IRIS
2007
Conference article
Open Access
Some preliminary ideas towards a theory of digital preservation
Meghini C, Giorgios F
The problem of digital preservation is one of the most challenging research problems faced by the community of digital libraries today, receiving growing interest by researchers and practitioners alike. One of the major gaps in the related research is the lack of a general agreement on a formal model to describe the problem or on a formal description of the required properties of a good solution to the problem. This work aims to fill this gap by presenting a number of ideas towards a formal, mathematical, logic-based description of preservation as a scientific discipline, to the end of deriving a methodology resting on solid theoretical grounds. We will present and justify a number of desired properties of such a formalism and introduce a model that handles the static aspects of the problem; some ideas related to the dynamics of preservation will be presented as well.
Meghini C, Giorgios F
The problem of digital preservation is one of the most challenging research problems faced by the community of digital libraries today, receiving growing interest by researchers and practitioners alike. One of the major gaps in the related research is the lack of a general agreement on a formal model to describe the problem or on a formal description of the required properties of a good solution to the problem. This work aims to fill this gap by presenting a number of ideas towards a formal, mathematical, logic-based description of preservation as a scientific discipline, to the end of deriving a methodology resting on solid theoretical grounds. We will present and justify a number of desired properties of such a formalism and introduce a model that handles the static aspects of the problem; some ideas related to the dynamics of preservation will be presented as well.
See at:
CNR IRIS | www.delos.info | CNR IRIS
2007
Conference article
Open Access
Terminology and Wish List for a Formal Theory of Preservation
Meghini C, Flouris G
The ability to access and understand digital information in the long term has been the subject of study of the digital preservation field, which is one of the most challenging research problems faced by the community of digital libraries today. The related research has produced a number of ad-hoc solutions which deal mainly with the static aspects of the problem. In this paper we take a different path in an attempt to formally describe the dynamic aspects of the problem. We describe and justify a number of desired properties of a good solution to the problem, as well as the basic steps required in order to get an adequate such formalism. This paper is part of a larger ongoing work towards developing a formal, mathematical, logic-based description of preservation as a scientific discipline, to the end of deriving a methodology resting on solid theoretical grounds.
Meghini C, Flouris G
The ability to access and understand digital information in the long term has been the subject of study of the digital preservation field, which is one of the most challenging research problems faced by the community of digital libraries today. The related research has produced a number of ad-hoc solutions which deal mainly with the static aspects of the problem. In this paper we take a different path in an attempt to formally describe the dynamic aspects of the problem. We describe and justify a number of desired properties of a good solution to the problem, as well as the basic steps required in order to get an adequate such formalism. This paper is part of a larger ongoing work towards developing a formal, mathematical, logic-based description of preservation as a scientific discipline, to the end of deriving a methodology resting on solid theoretical grounds.
See at:
CNR IRIS | www.pv2007.dlr.de | CNR IRIS
2007
Conference article
Restricted
Viewing Collections as Abstractions
Meghini C, Spyratos N
Digital Libraries collections are an abstraction mechanism, endowed with an extension and an intension, similarly to predicates in logic. The extension of a collection is the set of objects that are members of the collection at a given point in time, while the intension is a description of the meaning of the collection, that is the peculiar property that the members of the collection possess and that distinguishes the collection from other collections. This view reconciles the many types of collections found in Digital Library systems, but raises several problems, among which how to automatically derive the intension from a given extension. This problem must be solved e.g. for the creation of a collection from a set of documents. We outline basic results on the problem and then show how intensions can be exploited for carrying out basic tasks on collections, establishing a connection between Digital Library management and data integration.
Meghini C, Spyratos N
Digital Libraries collections are an abstraction mechanism, endowed with an extension and an intension, similarly to predicates in logic. The extension of a collection is the set of objects that are members of the collection at a given point in time, while the intension is a description of the meaning of the collection, that is the peculiar property that the members of the collection possess and that distinguishes the collection from other collections. This view reconciles the many types of collections found in Digital Library systems, but raises several problems, among which how to automatically derive the intension from a given extension. This problem must be solved e.g. for the creation of a collection from a set of documents. We outline basic results on the problem and then show how intensions can be exploited for carrying out basic tasks on collections, establishing a connection between Digital Library management and data integration.
2007
Conference article
Restricted
CASPAR project and the validation of digital preservation techniques
Meghini C, Et A
The CASPAR project is an Integrated Project part funded by the European Union. It seeks to develop tools and techniques to support the preservation of digitally encoded information. Underpinning the project are the themes of the OAIS Reference Model, and also of validation of that model and of the tools which CASPAR develops. The immediate challenges are from the domains of science, performing arts and cultural heritage. In each of these areas we look at a variety of preservation scenarios in which there are changes to hardware, software, environment and the knowledgebase of the Designated Community. It is believed that CASPAR will be relevant to the preservation not only of these domains but also for many other, perhaps all, types of digital information. CASPAR started in April 2006 and has developed a validation strategy which should be broadly applicable to projects which claim to be able to support digital preservation efforts. The presentation will report on this validation approach.
Meghini C, Et A
The CASPAR project is an Integrated Project part funded by the European Union. It seeks to develop tools and techniques to support the preservation of digitally encoded information. Underpinning the project are the themes of the OAIS Reference Model, and also of validation of that model and of the tools which CASPAR develops. The immediate challenges are from the domains of science, performing arts and cultural heritage. In each of these areas we look at a variety of preservation scenarios in which there are changes to hardware, software, environment and the knowledgebase of the Designated Community. It is believed that CASPAR will be relevant to the preservation not only of these domains but also for many other, perhaps all, types of digital information. CASPAR started in April 2006 and has developed a validation strategy which should be broadly applicable to projects which claim to be able to support digital preservation efforts. The presentation will report on this validation approach.