Symbolic user-defined periodicity in temporal relational databases

Terenziani, Paolo

doi:10.1109/tkde.2003.1185847

Cited by 36 publications

(48 citation statements)

References 41 publications

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“…In our approach (as in BCDM) the semantics of data, manipulation and query operation is modeled in a formal way, to provide a rigorous and non-ambiguous specification to implementers, and to provide a solid theoretical environment in which fundamental properties such as reducibility and consistent extension [8] can be formally proved. Thus, our work belongs to the temporal-database research and, specifically, to the stream of approaches extending BCDM to cope with new phenomena, such as periodic data [14], telic events [15], and different forms of temporal indeterminacy [16].…”

Section: R ----------------mentioning

confidence: 99%

Extending BCDM to Cope with Proposals and Evaluations of Updates

Anselma

Bottrighi

Montani

et al. 2013

IEEE Trans. Knowl. Data Eng.

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Abstract-The cooperative construction of data/knowledge bases has recently had a significant impulse (see, e.g., Wikipedia [1]). In cases in which data/knowledge quality and reliability are crucial, proposals of update/insertion/deletion need to be evaluated by experts. To the best of our knowledge, no theoretical framework has been devised to model the semantics of update proposal/evaluation in the relational context. Since time is an intrinsic part of most domains (as well as of the proposal/evaluation process itself), semantic approaches to temporal relational databases (specifically, Bitemporal Conceptual Data Model (henceforth, BCDM) [2]) are the starting point of our approach. In this paper, we propose BCDM PV , a semantic temporal relational model that extends BCDM to deal with multiple update/insertion/deletion proposals and with acceptances/rejections of proposals themselves. We propose a theoretical framework, defining the new data structures, manipulation operations and temporal relational algebra and proving some basic properties, namely that BCDM PV is a consistent extension of BCDM and that it is reducible to BCDM. These properties ensure consistency with most relational temporal database frameworks, facilitating implementations.

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Section: R ----------------mentioning

confidence: 99%

Extending BCDM to Cope with Proposals and Evaluations of Updates

Anselma

Bottrighi

Montani

et al. 2013

IEEE Trans. Knowl. Data Eng.

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“…Multislices are based on various formalisms coming from the research community [4,6,7,2] and generalize some known representations used in industry [8,9].…”

Section: Related Workmentioning

confidence: 99%

“…Kasperovics et al [1] introduced multislices as a basic object for representing recurrences, defined the difference operation on time slices and multislices, and proposed a scalable representation of multislices in relational databases. There is a number of works improving the expressiveness of time slices (e.g., [10,11,12,2]), or incorporating them into more complex representation formalisms (e.g., [13,7,14]). In this paper we presented an operation that constructs multislice representation for a given recurrence, which was not addressed by the previous works.…”

Section: Related Workmentioning

confidence: 99%

On the Efficient Construction of Multislices from Recurrences

Kasperovičs

Böhlen

Gamper

2010

Lecture Notes in Computer Science

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Recurrences are defined as sets of time instants associated with events and they are present in many application domains, including public transport schedules and personal calendars. Because of their large size, recurrences are rarely stored explicitly, but some form of compact representation is used. Multislices are a compact representation that is well suited for storage in relational databases. A multislice is a set of time slices where each slice employs a hierarchy of time granularities to compactly represent multiple recurrences. In this paper we investigate the construction of multislices from recurrences. We define the compression ratio of a multislice, show that different construction strategies produce multislices with different compression ratios, and prove that the construction of minimal multislices, i.e., multislices with a maximal compression ratio, is an NP-hard problem. We propose a scalable algorithm, termed LMerge, for the construction of multislices from recurrences. Experiments with real-world recurrences from public transport schedules confirm the scalability and usefulness of LMerge: the generated multislices are very close to minimal multislices, achieving an average compression ratio of approx. 99%. A comparison with a baseline algorithm that iteratively merges pairs of mergeable slices shows significant improvements of LMerge over the baseline approach. Abstract. Recurrences are defined as sets of time instants associated with events and they are present in many application domains, including public transport schedules and personal calendars. Because of their large size, recurrences are rarely stored explicitly, but some form of compact representation is used. Multislices are a compact representation that is well suited for storage in relational databases. A multislice is a set of time slices where each slice employs a hierarchy of time granularities to compactly represent multiple recurrences. On the Efficient Construction of Multislices from RecurrencesIn this paper we investigate the construction of multislices from recurrences. We define the compression ratio of a multislice, show that different construction strategies produce multislices with different compression ratios, and prove that the construction of minimal multislices, i.e., multislices with a maximal compression ratio, is an NP-hard problem. We propose a scalable algorithm, termed LMerge, for the construction of multislices from recurrences. Experiments with real-world recurrences from public transport schedules confirm the scalability and usefulness of LMerge: the generated multislices are very close to minimal multislices, achieving an average compression ratio of approx. 99%. A comparison with a baseline algorithm that iteratively merges pairs of mergeable slices shows significant improvements of LMerge over the baseline approach.

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“…In our previous work, we defined a high-level language to deal with user-defined periodicity (Terenziani 2003a) and with period-dependent qualitative temporal constraints between repeated events (which are coped with as 'classes' of events) and constraint propagation algorithms operating on them (Terenziani 1997(Terenziani , 2003b. We also proposed an initial algorithm to check the consistency of a knowledge base of such constraints with a set of instances of events exactly located in time (Terenziani 2000).…”

Section: Related Workmentioning

confidence: 99%

Temporal reasoning about composite and/or periodic events

Terenziani

Anselma

2006

Journal of Experimental & Theoretical Artificial Intelligen

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In many application areas, including planning, workflow, guideline and protocol management, the description of the domain involves composite and/or periodic events, mutually related by temporal constraints on the execution order. Such events represent 'classes', since they can be instantiated to specific executions of the plan, guideline etc., and each execution must 'respect' the temporal constraints imposed on the corresponding classes. The main objective of our work is that of proposing an approach dealing with the above-mentioned temporal phenomena. To achieve such an objective, we propose a tractable domain-independent temporal reasoner. This enhances the generality of our approach, which provides a domain-independent module which can be integrated with other software tools to solve temporal problems in specific domains.From the methodological point of view, we first devise a representation formalism coping with the aforesaid phenomena, and then we describe temporal constraint propagation algorithms to deal with constraint inheritance and to perform temporal consistency checking. The representation formalism has been designed carefully, to obtain algorithms that are both complete and tractable. Finally, the paper also shows experimental results, including an application of our approach to clinical guidelines, evaluating their impact on future applications and research activities.

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Symbolic user-defined periodicity in temporal relational databases

Cited by 36 publications

References 41 publications

Extending BCDM to Cope with Proposals and Evaluations of Updates

Extending BCDM to Cope with Proposals and Evaluations of Updates

On the Efficient Construction of Multislices from Recurrences

Temporal reasoning about composite and/or periodic events

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