The goal of this paper is the generalization of embedding and confluence results for graph transformation systems to transformation systems with negative application conditions (NACs). These conditions restrict the application of a rule by expressing that a specific structure must not be present before or after applying the rule to a certain context. Such a condition influences each rule applic...

We are interested in observing changes to a particular web graph community over time. A small subset of the entire web graph can provide sufficient information about our community of interest. Therefore we use a local approach where knowledge of the entire web graph is not needed. In this paper we will consider how we may track the evolution of a community from a local point of view and analyze...

This paper discusses a new approach to QoS routing, introducing the notion of algorithm resilience (i.e., its capability to adapt to network and load modifications) as performance index of the algorithm itself. The new approach can be summarized as Network Graph Reduction, i.e., a modification of the graph describing the network before the routing path is computed, in order to exclude from the ...

The data structure SPQR-tree represents the decomposition of a biconnected graph with respect to its triconnected components. SPQR-trees have been introduced by Di Battista and Tamassia [8] and, since then, became quite important in the field of graph algorithms. Theoretical papers using SPQR-trees claim that they can be implemented in linear time using a modification of the algorithm by Hopcro...

We investigate the following modification of a problem posed by Karoński, Luczak and Thomason [J. Combin. Theory, Ser. B 91 (2004) 151-157]. Let us assign positive integers to the edges and vertices of a simple graph G. As a result we obtain a vertex-colouring of G by sums of weights assigned to the vertex and its adjacent edges. Can we obtain a proper colouring using only weights 1 and 2 for a...

Graph databases are constantly growing, and, at the same time, some of their data is the same or similar. Our experience with the management of the existing databases, especially the bigger ones, shows that certain vertices are particularly replicated there numerous times. Eliminating repetitive or even very similar data speeds up the access to database resources. We present a modification of t...

We consider the following graph modification problem. Let the input consist of a graph G = (V,E), a weight function w : V ∪E → N, a cost function c : V ∪E → N and a degree function δ : V → N0, together with three integers kv, ke and C. The question is whether we can delete a set of vertices of total weight at most kv and a set of edges of total weight at most ke so that the total cost of the de...

Programmers tend to spend a lot of time debugging code. They check the erroneous phenomena, navigate the code, search the past bug fixes, and modify the code. If a sequence of these debug activities can be automated, programmers can use their time for more creative tasks. To address this problem, this paper proposes dcNavi (Debug Concern Navigator), a concern-oriented recommendation system for ...

Factor graphs, and message-passing over these graphs using the Sum-Product Algorithm (SPA), are an important method for unifying the tasks of channel estimation and decoding. In this paper, we use a variant of the Expectation-Maximization (EM) Algorithm that is formulated as a modification to the sum-product algorithm (SPA) over factor graphs. We firstly advance the theory of this factor graph ...

Given a fixed graph H, the H-Free Edge Deletion (resp., Completion, Editing) problems ask whether it is possible to delete from (resp., add to, delete from or add to) the input graph at most k edges so that the resulting graph is H-free, i.e., contains no induced subgraph isomorphic to H. These H-free edge modification problems are well known to be FPT for every fixed H. In this paper, we study...