In early 2000’s, Rivest [Riv00,MR02] and Micali [MR02] introduced the notion of transitive signature, which allows a third party to generate a valid signature for a composed edge (vi, vk), from the signatures for two edges (vi, vj) and (vj , vk), and using the public key only. Since then, a number of works, including [MR02,BN02,Hoh03,SFSM05,BN05], have been devoted on transitive signatures. Mos...

Temporality-driven covariate classification had limited impact on: the specification of directed acyclic graphs (DAGs) by 85 novice analysts (medical undergraduates); or risk bias in DAG-informed multivariable models designed to generate causal inference from observational data. Only 71 students (83.5%) managed complete “Temporality-driven Covariate Classification” task, and fewer still complet...

A characterization is given for acyclic digraphs that are the acyclic intersection digraphs of subpaths of a directed tree.

qYaditionally, constraint satisfaction problems (CSPs) are characterized using a finite set of constraints expressed within a common, shared constraint language. When reasoning across time, however, it is possible to express both temporal and state-based constraints represented within multiple constraint languages. Qualitative simulation provides an instance of this class of CSP in which, tradi...

Considering the theory of attribute grammars, we use logical formulas instead of traditional functional semantic rules. Following the decoration of a derivation tree, a suitable algorithm should maintain the consistency of the formulas together with the evaluation of the attributes. This may be a Prolog-like resolution, but this paper examines a somewhat different strategy, based on production ...

Traditionally, constraint satisfaction problems (CSPs) are characterized using a nite set of constraints expressed within a common, shared constraint language. When reasoning across time, however, it is possible to express both temporal and state{based constraints represented within multiple constraint languages. Qualitative simulation provides an instance of this class of CSP in which, traditi...

We revisit the complexity of the model checking problem for formulas of linear-time temporal logic (LTL). We show that the classic PSPACE-hardness result is actually limited to a subclass of the Kripke frames, which is characterized by a simple structural condition: the model checking problem is only PSPACE-hard if there exists a strongly connected component with two distinct cycles. If no such...

The paper explores the relationship between tree languages definable in LTL, CTL, and ACTL, the fragment of CTL where only universal path quantification is allowed. The common fragment of LTL and ACTL is shown to be strictly smaller than the common fragment of LTL and CTL. Furthermore, an algorithm is presented for deciding if an LTL formula can be expressed in ACTL. This algorithm uses an effe...

A query optimizer requires cost models to calculate the costs of various access plans for a query. An effective method to estimate the number of disk (or page) accesses for spatio-temporal queries has not yet been proposed. The TPR-tree is an efficient index that supports spatio-temporal queries for moving objects. Existing cost models for the spatial index such as the R-tree do not accurately ...