We introduce linear expressions for unrestricted dags (directed acyclic graphs) and finite deterministic and nondeterministic automata operating on them. Those dag automata are a conservative extension of the Tu,u-automata of Courcelle on unranked, unordered trees and forests. Several examples of dag languages acceptable and not acceptable by dag automata and some closure properties are given.

Consider a directed graph (digraph) in which vertices are assigned color sets, and two connected if only they share at least one the tail vertex has strictly smaller set than head. We seek to determine smallest possible size of union sets that allows for such digraph representation. To address this problem, we introduce new notion intersection representation digraph, show it is well-defined all...

I declare that I have developed and written the enclosed thesis completely by myself, and have not used sources or means without declaration in the text. A reachability query on a directed graph G asks if there exists a path from a node s to a node t. Answering such queries on large graph like datasets has become an issue in various fields of research and real world applications over the past 2...

With the arrival of 5G era, Internet Things (IoT) has entered a new stage, and amount IoT data is growing rapidly. The traditional blockchain cannot handle massive amounts data, which presents scalability challenges for technology. Existing improvement technologies such as off-chain payments, protocol improvements, sharding techniques have performance bottlenecks limitations in rapidly growing....

Distributed systems such as Grid- and Cloud Computing provision web services to their users in all of the world. One of the most important concerns which service providers encounter is to handle total cost of ownership (TCO). The large part of TCO is related to power consumption due to inefficient resource management. Task scheduling module as a key component can has drastic impact on both user...

Causal relationships among a set of variables is commonly represented by directed acyclic graph. The orientations some edges in the causal DAG can be discovered from observational/interventional data. Further oriented iteratively applying so-called Meek rules. Inferring edges' previously edges, which we call Orientation Learning (COL), common problem various discovery tasks. In these tasks, it ...

In a previous paper [Pearl and Verma, 1991] we presented an algorithm for extracting causal influences from independence informa­ tion, where a causal influence was defined as the existence of a directed arc in all mini­ mal causal models consistent with the data. In this paper we address the question of de­ ciding whether there exists a causal model that explains ALL the observed dependencies ...

Su¢ cient-component causes are incorporated into the directed acyclic graph (DAG) causal framework in order to make apparent several properties of conditioning on a common e¤ect. By incorporating su¢ cient causes on a graph, it is possible to detect conditional independencies within strata of the conditioning variable which are not evident on DAGs without the representation of su¢ cient causes....

A digraph that represents reasonably a scheduling problem should have no cycles i.e. it should be DAG i.e. a directed acyclic graph. Here down we shall deal with special kind of graded DAGs named KoDAGs. For their definition and first primary properties see [1], where natural join of di-bigraphs (directed bi-parted graphs) and their corresponding adjacency matrices is defined and then applied t...

Existing work for query processing over graph data models often relies on pre-computing the transitive closure or path indexes. In this paper, we propose a family of stack-based algorithms to handle path, twig, and dag pattern queries for directed acyclic graphs (DAGs) in particular. Our algorithms do not precompute the transitive closure nor path indexes for a given graph, however they achieve...