This study examined the effects of cognitive task complexity increase on the complexity, accuracy, and fluency (CAF) as well as the temporal distribution of the cognitive and metacognitive processes involved in computer-mediated L2 written production. To this end, the study employed a between-subjects experimental design with 85 EFL learners from a language learning institute in Iran. Participa...

Temporal databases introduce the concept of time into underlying data, and provide built-in facilities that allow users to store and retrieve time-varying data. The aggregation in temporal databases, that is, temporal aggregation is an extension of conventional aggregation on the domain and range of aggregates to include time concept. Temporal aggregation is important for various applications, ...

In this paper we address the edge-agreement problem with preserved connectivity for networks of first and second-order systems under proximity constraints interconnected over a class directed graphs. We provide strict Lyapunov function that leads to establishing uniform asymptotic stability consensus manifold guaranteed preservation. Furthermore, robustness protocol, in sense input-to-state res...

Navigating through hyperlinks within a Web site to look for information from one of its Web pages without the support of a site map can be inefficient and ineffective. Although the content of a Web site is usually organized with an inherent structure like a topic hierarchy, which is a directed tree rooted at a Web site’s homepage whose vertices and edges correspond to Web pages and hyperlinks, ...

Given a directed graph G and a list (s1, t1), . . . , (sk, tk) of terminal pairs, the Directed Steiner Network problem asks for a minimum-cost subgraph of G that contains a directed si → ti path for every 1 ≤ i ≤ k. The special case Directed Steiner Tree (when we ask for paths from a root r to terminals t1, . . . , tk) is known to be fixed-parameter tractable parameterized by the number of term...

The Markov Chain Tree Theorem is a classical result which expresses the stable distribution of an irreducible Markov matrix in terms of directed spanning trees of its associated graph. In this article, we present what we believe to be an original elementary proof of the theorem (Theorem 5.1). Our proof uses only linear algebra and graph theory, and in particular, it does not rely on probability...

Let T = (V,A) be a directed tree. Given a collection P of dipaths on T , we can look at the arc-intersection graph I(P, T ) whose vertex set is P and where two vertices are connected by an edge if the corresponding dipaths share a common arc. Monma and Wei, who started their study in a seminal paper on intersection graphs of paths on a tree, called them DE graphs (for directed edge path graphs)...

Over-constrained temporal problems are commonly encountered while operating autonomous and decision support systems. An intelligent system must learn a human’s preference over a problem in order to generate preferred resolutions that minimize perturbation. We present the Best-first Conflict-Directed Relaxation (BCDR) algorithm for enumerating the best continuous relaxation for an over-constrain...