In this paper, we propose a formal de nition of temporal validity which we believe is the rst and the most comprehensive quanti cation of that notion. The temporal validity is developed into the notion of sort of validity with which the confusion among various time concepts introduced for temporal databases can be dispelled. Further, we discuss the problem of preserving multiple past states of ...

Adding a temporal dimension to multimedia data is an interesting research topic, in particular with reference to the fruition of the cultural heritage. Time may be viewed either as valid-time or as transaction-time. In the rst sense, planning a virtual visit in time means working out a path that leads through the centuries taking into account the di erent historical contexts when the works of a...

Much research work has recently focused on the problem of representing historical information in XML. In this paper, we describe an ongoing work to represent XML changes. Our model is a three-dimensional XML-based model (3D_XML in short) for representing and querying histories of XML documents. The proposed model incorporates three time dimensions, valid time, transaction time, and efficacy tim...

A standard relation is two-dimensional with attributes and tuples as dimensions. A temporal relation contains two additional, orthogonal time dimensions, namely valid time and transaction time. Valid time records when facts are true in the modeled reality, and transaction time records when facts are stored in the temporal relation. While, in general, there are no restrictions between the valid ...

Knowledge graph (KG) completion adds new facts to a KG by making inferences from existing facts. Most existing methods ignore the time information and only learn from time-unknown fact triples. In dynamic environments that evolve over time, it is important and challenging for knowledge graph completion models to take into account the temporal aspects of facts. In this paper, we present a novel ...

We propose a method for integrity checking in the context of temporal deductive databases. A temporal deductive database is a deductive database that supports some aspect of time, in our case valid time, in which valid time is the time when the fact is true in the modelled reality. Our method augments a database with a set of transition and event rules, which explicitly define the insertions an...

DEFINITION A bi-temporal index is a data structure that supports both temporal time dimensions, namely, transactiontime (the time when a fact is stored in the database) and valid-time (the time when a fact becomes valid in reality). The characteristics of the time dimensions supported imply various properties that the bi-temporal index should have to be efficient. As traditional indices, the pe...

Access control is one of the most important technologies to guarantee computer security. A new model with support for valid time and usage constraint is described based on full analysis of flaws in existing models. In the new model, authorization rules can express access control policies completely and access constraints are necessary conditions to prevent authorization abuse. To solve the prob...

Induction of transplantation tolerance remains the ideal long-term clinical and logistic solution to the current challenges facing the management of renal allograft recipients. In this review, we describe the recent studies and advances made in identifying biomarkers of renal transplant tolerance, from study inceptions, to the lessons learned and their implications for current and future studie...